InVivoMAb anti-mouse PD-1 (CD279)
Product Description
Specifications
| Isotype | Rat IgG2a, κ |
|---|---|
| Recommended Isotype Control(s) | InVivoMAb rat IgG2a isotype control, anti-trinitrophenol |
| Recommended Dilution Buffer | InVivoPure pH 7.0 Dilution Buffer |
| Conjugation | This product is unconjugated. Conjugation is available via our Antibody Conjugation Services. |
| Immunogen | Syrian Hamster BKH cells transfected with mouse PD-1 cDNA |
| Reported Applications |
in vivo blocking of PD-1/PD-L signaling in vitro Organoids/Organ-on-Chip |
| Formulation |
PBS, pH 7.0 Contains no stabilizers or preservatives |
| Endotoxin |
≤1EU/mg (≤0.001EU/μg) Determined by LAL assay |
| Purity |
≥95% Determined by SDS-PAGE |
| Sterility | 0.2 µm filtration |
| Production | Purified from cell culture supernatant in an animal-free facility |
| Purification | Protein G |
| RRID | AB_10949053 |
| Molecular Weight | 150 kDa |
| Storage | The antibody solution should be stored at the stock concentration at 4°C. Do not freeze. |
| Need a Custom Formulation? | See All Antibody Customization Options |
Application References
in vivo blocking of PD-1/PD-L signaling
Nakazawa Y, Miyano M, Tsukamoto S, Kogai H, Yamamoto A, Iso K, Inoue S, Yamane Y, Yabe Y, Umihara H, Taguchi J, Akagi T, Yamaguchi A, Koga M, Toshimitsu K, Hirayama T, Mukai Y, Machinaga A (2024). "Delivery of a BET protein degrader via a CEACAM6-tar
PubMed
Pancreatic ductal adenocarcinoma (PDAC) has the worst prognosis of all cancers. To improve PDAC therapy, we establish screening systems based on organoid and co-culture technologies and find a payload of antibody-drug conjugate (ADC), a bromodomain and extra-terminal (BET) protein degrader named EBET. We select CEACAM6/CD66c as an ADC target and developed an antibody, #84.7, with minimal reactivity to CEACAM6-expressing normal cells. EBET-conjugated #84.7 (84-EBET) has lethal effects on various PDAC organoids and bystander efficacy on CEACAM6-negative PDAC cells and cancer-associated fibroblasts. In mouse studies, a single injection of 84-EBET induces marked tumor regression in various PDAC-patient-derived xenografts, with a decrease in the inflammatory phenotype of stromal cells and without significant body weight loss. Combination with standard chemotherapy or PD-1 antibody induces more profound and sustained regression without toxicity enhancement. Our preclinical evidence demonstrates potential efficacy by delivering BET protein degrader to PDAC and its microenvironment via CEACAM6-targeted ADC.
in vitro Organoids/Organ-on-Chip
in vivo blocking of PD-1/PD-L signaling
Holokai L, Chakrabarti J, Lundy J, Croagh D, Adhikary P, Richards SS, Woodson C, Steele N, Kuester R, Scott A, Khreiss M, Frankel T, Merchant J, Jenkins BJ, Wang J, Shroff RT, Ahmad SA, Zavros Y (2020). "Murine- and Human-Derived Autologous Organoid/
PubMed
Purpose: Pancreatic ductal adenocarcinoma (PDAC) has the lowest five-year survival rate of all cancers in the United States. Programmed death 1 receptor (PD-1)-programmed death ligand 1 (PD-L1) immune checkpoint inhibition has been unsuccessful in clinical trials. Myeloid-derived suppressor cells (MDSCs) are known to block anti-tumor CD8+ T cell immune responses in various cancers including pancreas. This has led us to our objective that was to develop a clinically relevant in vitro organoid model to specifically target mechanisms that deplete MDSCs as a therapeutic strategy for PDAC. Method: Murine and human pancreatic ductal adenocarcinoma (PDAC) autologous organoid/immune cell co-cultures were used to test whether PDAC can be effectively treated with combinatorial therapy involving PD-1 inhibition and MDSC depletion. Results: Murine in vivo orthotopic and in vitro organoid/immune cell co-culture models demonstrated that polymorphonuclear (PMN)-MDSCs promoted tumor growth and suppressed cytotoxic T lymphocyte (CTL) proliferation, leading to diminished efficacy of checkpoint inhibition. Mouse- and human-derived organoid/immune cell co-cultures revealed that PD-L1-expressing organoids were unresponsive to nivolumab in vitro in the presence of PMN-MDSCs. Depletion of arginase 1-expressing PMN-MDSCs within these co-cultures rendered the organoids susceptible to anti-PD-1/PD-L1-induced cancer cell death. Conclusions: Here we use mouse- and human-derived autologous pancreatic cancer organoid/immune cell co-cultures to demonstrate that elevated infiltration of polymorphonuclear (PMN)-MDSCs within the PDAC tumor microenvironment inhibit T cell effector function, regardless of PD-1/PD-L1 inhibition. We present a pre-clinical model that may predict the efficacy of targeted therapies to improve the outcome of patients with this aggressive and otherwise unpredictable malignancy.
in vivo blocking of PD-1/PD-L signaling
Triplett, T. A., et al (2018). "Reversal of indoleamine 2,3-dioxygenase-mediated cancer immune suppression by systemic kynurenine depletion with a therapeutic enzyme" Nat Biotechnol 36(8): 758-764.
PubMed
Increased tryptophan (Trp) catabolism in the tumor microenvironment (TME) can mediate immune suppression by upregulation of interferon (IFN)-gamma-inducible indoleamine 2,3-dioxygenase (IDO1) and/or ectopic expression of the predominantly liver-restricted enzyme tryptophan 2,3-dioxygenase (TDO). Whether these effects are due to Trp depletion in the TME or mediated by the accumulation of the IDO1 and/or TDO (hereafter referred to as IDO1/TDO) product kynurenine (Kyn) remains controversial. Here we show that administration of a pharmacologically optimized enzyme (PEGylated kynureninase; hereafter referred to as PEG-KYNase) that degrades Kyn into immunologically inert, nontoxic and readily cleared metabolites inhibits tumor growth. Enzyme treatment was associated with a marked increase in the tumor infiltration and proliferation of polyfunctional CD8(+) lymphocytes. We show that PEG-KYNase administration had substantial therapeutic effects when combined with approved checkpoint inhibitors or with a cancer vaccine for the treatment of large B16-F10 melanoma, 4T1 breast carcinoma or CT26 colon carcinoma tumors. PEG-KYNase mediated prolonged depletion of Kyn in the TME and reversed the modulatory effects of IDO1/TDO upregulation in the TME.
in vivo blocking of PD-1/PD-L signaling
Grasselly, C., et al (2018). "The Antitumor Activity of Combinations of Cytotoxic Chemotherapy and Immune Checkpoint Inhibitors Is Model-Dependent" Front Immunol 9: 2100.
PubMed
In spite of impressive response rates in multiple cancer types, immune checkpoint inhibitors (ICIs) are active in only a minority of patients. Alternative strategies currently aim to combine immunotherapies with conventional agents such as cytotoxic chemotherapies. Here, we performed a study of PD-1 or PDL-1 blockade in combination with reference chemotherapies in four fully immunocompetent mouse models of cancer. We analyzed both the in vivo antitumor response, and the tumor immune infiltrate 4 days after the first treatment. in vivo tumor growth experiments revealed variable responsiveness to ICIs between models. We observed enhanced antitumor effects of the combination of immunotherapy with chemotherapy in the MC38 colon and MB49 bladder models, a lack of response in the 4T1 breast model, and an inhibition of ICIs activity in the MBT-2 bladder model. Flow cytometry analysis of tumor samples showed significant differences in all models between untreated and treated mice. At baseline, all the tumor models studied were predominantly infiltrated with cells harboring an immunosuppressive phenotype. Early alterations of the tumor immune infiltrate after treatment were found to be highly variable. We found that the balance between effector cells and immunosuppressive cells in the tumor microenvironment could be altered with some treatment combinations, but this effect was not always correlated with an impact on in vivo tumor growth. These results show that the combination of cytotoxic chemotherapy with ICIs may result in enhanced, similar or reduced antitumor activity, in a model- and regimen-dependent fashion. The present investigations should help to select appropriate combination regimens for ICIs.
in vivo blocking of PD-1/PD-L signaling
Moynihan, K. D., et al (2016). "Eradication of large established tumors in mice by combination immunotherapy that engages innate and adaptive immune responses" Nat Med. doi : 10.1038/nm.4200.
PubMed
Checkpoint blockade with antibodies specific for cytotoxic T lymphocyte-associated protein (CTLA)-4 or programmed cell death 1 (PDCD1; also known as PD-1) elicits durable tumor regression in metastatic cancer, but these dramatic responses are confined to a minority of patients. This suboptimal outcome is probably due in part to the complex network of immunosuppressive pathways present in advanced tumors, which are unlikely to be overcome by intervention at a single signaling checkpoint. Here we describe a combination immunotherapy that recruits a variety of innate and adaptive immune cells to eliminate large tumor burdens in syngeneic tumor models and a genetically engineered mouse model of melanoma; to our knowledge tumors of this size have not previously been curable by treatments relying on endogenous immunity. Maximal antitumor efficacy required four components: a tumor-antigen-targeting antibody, a recombinant interleukin-2 with an extended half-life, anti-PD-1 and a powerful T cell vaccine. Depletion experiments revealed that CD8+ T cells, cross-presenting dendritic cells and several other innate immune cell subsets were required for tumor regression. Effective treatment induced infiltration of immune cells and production of inflammatory cytokines in the tumor, enhanced antibody-mediated tumor antigen uptake and promoted antigen spreading. These results demonstrate the capacity of an elicited endogenous immune response to destroy large, established tumors and elucidate essential characteristics of combination immunotherapies that are capable of curing a majority of tumors in experimental settings typically viewed as intractable.
in vivo blocking of PD-1/PD-L signaling
Twyman-Saint Victor, C., et al (2015). "Radiation and dual checkpoint blockade activate non-redundant immune mechanisms in cancer" Nature 520(7547): 373-377.
PubMed
Immune checkpoint inhibitors result in impressive clinical responses, but optimal results will require combination with each other and other therapies. This raises fundamental questions about mechanisms of non-redundancy and resistance. Here we report major tumour regressions in a subset of patients with metastatic melanoma treated with an anti-CTLA4 antibody (anti-CTLA4) and radiation, and reproduced this effect in mouse models. Although combined treatment improved responses in irradiated and unirradiated tumours, resistance was common. Unbiased analyses of mice revealed that resistance was due to upregulation of PD-L1 on melanoma cells and associated with T-cell exhaustion. Accordingly, optimal response in melanoma and other cancer types requires radiation, anti-CTLA4 and anti-PD-L1/PD-1. Anti-CTLA4 predominantly inhibits T-regulatory cells (Treg cells), thereby increasing the CD8 T-cell to Treg (CD8/Treg) ratio. Radiation enhances the diversity of the T-cell receptor (TCR) repertoire of intratumoral T cells. Together, anti-CTLA4 promotes expansion of T cells, while radiation shapes the TCR repertoire of the expanded peripheral clones. Addition of PD-L1 blockade reverses T-cell exhaustion to mitigate depression in the CD8/Treg ratio and further encourages oligoclonal T-cell expansion. Similarly to results from mice, patients on our clinical trial with melanoma showing high PD-L1 did not respond to radiation plus anti-CTLA4, demonstrated persistent T-cell exhaustion, and rapidly progressed. Thus, PD-L1 on melanoma cells allows tumours to escape anti-CTLA4-based therapy, and the combination of radiation, anti-CTLA4 and anti-PD-L1 promotes response and immunity through distinct mechanisms.
in vivo blocking of PD-1/PD-L signaling
Zelenay, S., et al (2015). "Cyclooxygenase-Dependent Tumor Growth through Evasion of Immunity" Cell 162(6): 1257-1270.
PubMed
The mechanisms by which melanoma and other cancer cells evade anti-tumor immunity remain incompletely understood. Here, we show that the growth of tumors formed by mutant Braf(V600E) mouse melanoma cells in an immunocompetent host requires their production of prostaglandin E2, which suppresses immunity and fuels tumor-promoting inflammation. Genetic ablation of cyclooxygenases (COX) or prostaglandin E synthases in Braf(V600E) mouse melanoma cells, as well as in Nras(G12D) melanoma or in breast or colorectal cancer cells, renders them susceptible to immune control and provokes a shift in the tumor inflammatory profile toward classic anti-cancer immune pathways. This mouse COX-dependent inflammatory signature is remarkably conserved in human cutaneous melanoma biopsies, arguing for COX activity as a driver of immune suppression across species. Pre-clinical data demonstrate that inhibition of COX synergizes with anti-PD-1 blockade in inducing eradication of tumors, implying that COX inhibitors could be useful adjuvants for immune-based therapies in cancer patients.
in vivo blocking of PD-1/PD-L signaling
Vanpouille-Box, C., et al (2015). "TGFbeta Is a Master Regulator of Radiation Therapy-Induced Antitumor Immunity" Cancer Res 75(11): 2232-2242.
PubMed
T cells directed to endogenous tumor antigens are powerful mediators of tumor regression. Recent immunotherapy advances have identified effective interventions to unleash tumor-specific T-cell activity in patients who naturally develop them. Eliciting T-cell responses to a patient’s individual tumor remains a major challenge. Radiation therapy can induce immune responses to model antigens expressed by tumors, but it remains unclear whether it can effectively prime T cells specific for endogenous antigens expressed by poorly immunogenic tumors. We hypothesized that TGFbeta activity is a major obstacle hindering the ability of radiation to generate an in situ tumor vaccine. Here, we show that antibody-mediated TGFbeta neutralization during radiation therapy effectively generates CD8(+) T-cell responses to multiple endogenous tumor antigens in poorly immunogenic mouse carcinomas. Generated T cells were effective at causing regression of irradiated tumors and nonirradiated lung metastases or synchronous tumors (abscopal effect). Gene signatures associated with IFNgamma and immune-mediated rejection were detected in tumors treated with radiation therapy and TGFbeta blockade in combination but not as single agents. Upregulation of programmed death (PD) ligand-1 and -2 in neoplastic and myeloid cells and PD-1 on intratumoral T cells limited tumor rejection, resulting in rapid recurrence. Addition of anti-PD-1 antibodies extended survival achieved with radiation and TGFbeta blockade. Thus, TGFbeta is a fundamental regulator of radiation therapy’s ability to generate an in situ tumor vaccine. The combination of local radiation therapy with TGFbeta neutralization offers a novel individualized strategy for vaccinating patients against their tumors.
in vivo blocking of PD-1/PD-L signaling
Evans, E. E., et al (2015). "Antibody Blockade of Semaphorin 4D Promotes Immune Infiltration into Tumor and Enhances Response to Other Immunomodulatory Therapies" Cancer Immunol Res 3(6): 689-701.
PubMed
Semaphorin 4D (SEMA4D, CD100) and its receptor plexin-B1 (PLXNB1) are broadly expressed in murine and human tumors, and their expression has been shown to correlate with invasive disease in several human tumors. SEMA4D normally functions to regulate the motility and differentiation of multiple cell types, including those of the immune, vascular, and nervous systems. In the setting of cancer, SEMA4D-PLXNB1 interactions have been reported to affect vascular stabilization and transactivation of ERBB2, but effects on immune-cell trafficking in the tumor microenvironment (TME) have not been investigated. We describe a novel immunomodulatory function of SEMA4D, whereby strong expression of SEMA4D at the invasive margins of actively growing tumors influences the infiltration and distribution of leukocytes in the TME. Antibody neutralization of SEMA4D disrupts this gradient of expression, enhances recruitment of activated monocytes and lymphocytes into the tumor, and shifts the balance of cells and cytokines toward a proinflammatory and antitumor milieu within the TME. This orchestrated change in the tumor architecture was associated with durable tumor rejection in murine Colon26 and ERBB2(+) mammary carcinoma models. The immunomodulatory activity of anti-SEMA4D antibody can be enhanced by combination with other immunotherapies, including immune checkpoint inhibition and chemotherapy. Strikingly, the combination of anti-SEMA4D antibody with antibody to CTLA-4 acts synergistically to promote complete tumor rejection and survival. Inhibition of SEMA4D represents a novel mechanism and therapeutic strategy to promote functional immune infiltration into the TME and inhibit tumor progression.
in vivo blocking of PD-1/PD-L signaling
Ngiow, S. F., et al (2015). "A Threshold Level of Intratumor CD8+ T-cell PD1 Expression Dictates Therapeutic Response to Anti-PD1" Cancer Res 75(18): 3800-3811.
PubMed
Despite successes, thus far, a significant proportion of the patients treated with anti-PD1 antibodies have failed to respond. We use mouse tumor models of anti-PD1 sensitivity and resistance and flow cytometry to assess tumor-infiltrating immune cells immediately after therapy. We demonstrate that the expression levels of T-cell PD1 (PD1(lo)), myeloid, and T-cell PDL1 (PDL1(hi)) in the tumor microenvironment inversely correlate and dictate the efficacy of anti-PD1 mAb and function of intratumor CD8(+) T cells. In sensitive tumors, we reveal a threshold for PD1 downregulation on tumor-infiltrating CD8(+) T cells below which the release of adaptive immune resistance is achieved. In contrast, PD1(hi) T cells in resistant tumors fail to be rescued by anti-PD1 therapy and remain dysfunctional unless intratumor PDL1(lo) immune cells are targeted. Intratumor Tregs are partly responsible for the development of anti-PD1-resistant tumors and PD1(hi) CD8(+) T cells. Our analyses provide a framework to interrogate intratumor CD8(+) T-cell PD1 and immune PDL1 levels and response in human cancer. Cancer Res; 75(18); 3800-11. (c)2015 AACR.
in vivo blocking of PD-1/PD-L signaling
Zander, R. A., et al (2015). "PD-1 Co-inhibitory and OX40 Co-stimulatory Crosstalk Regulates Helper T Cell Differentiation and Anti-Plasmodium Humoral Immunity" Cell Host Microbe 17(5): 628-641.
PubMed
The differentiation and protective capacity of Plasmodium-specific T cells are regulated by both positive and negative signals during malaria, but the molecular and cellular details remain poorly defined. Here we show that malaria patients and Plasmodium-infected rodents exhibit atypical expression of the co-stimulatory receptor OX40 on CD4 T cells and that therapeutic enhancement of OX40 signaling enhances helper CD4 T cell activity, humoral immunity, and parasite clearance in rodents. However, these beneficial effects of OX40 signaling are abrogated following coordinate blockade of PD-1 co-inhibitory pathways, which are also upregulated during malaria and associated with elevated parasitemia. Co-administration of biologics blocking PD-1 and promoting OX40 signaling induces excessive interferon-gamma that directly limits helper T cell-mediated support of humoral immunity and decreases parasite control. Our results show that targeting OX40 can enhance Plasmodium control and that crosstalk between co-inhibitory and co-stimulatory pathways in pathogen-specific CD4 T cells can impact pathogen clearance.
in vivo blocking of PD-1/PD-L signaling
McGray, A. J., et al (2014). "Immunotherapy-induced CD8+ T cells instigate immune suppression in the tumor" Mol Ther 22(1): 206-218.
PubMed
Despite clear evidence of immunogenicity, cancer vaccines only provide a modest clinical benefit. To evaluate the mechanisms that limit tumor regression following vaccination, we have investigated the weak efficacy of a highly immunogenic experimental vaccine using a murine melanoma model. We discovered that the tumor adapts rapidly to the immune attack instigated by tumor-specific CD8+ T cells in the first few days following vaccination, resulting in the upregulation of a complex set of biological networks, including multiple immunosuppressive processes. This rapid adaptation acts to prevent sustained local immune attack, despite continued infiltration by increasing numbers of tumor-specific T cells. Combining vaccination with adoptive transfer of tumor-specific T cells produced complete regression of the treated tumors but did not prevent the adaptive immunosuppression. In fact, the adaptive immunosuppressive pathways were more highly induced in regressing tumors, commensurate with the enhanced level of immune attack. Examination of tumor infiltrating T-cell functionality revealed that the adaptive immunosuppression leads to a progressive loss in T-cell function, even in tumors that are regressing. These novel observations that T cells produced by therapeutic intervention can instigate a rapid adaptive immunosuppressive response within the tumor have important implications for clinical implementation of immunotherapies.
in vivo blocking of PD-1/PD-L signaling
Mittal, D., et al (2014). "Antimetastatic effects of blocking PD-1 and the adenosine A2A receptor" Cancer Res 74(14): 3652-3658.
PubMed
Adenosine targeting is an attractive new approach to cancer treatment, but no clinical study has yet examined adenosine inhibition in oncology despite the safe clinical profile of adenosine A2A receptor inhibitors (A2ARi) in Parkinson disease. Metastasis is the main cause of cancer-related deaths worldwide, and therefore we have studied experimental and spontaneous mouse models of melanoma and breast cancer metastasis to demonstrate the efficacy and mechanism of a combination of A2ARi in combination with anti-PD-1 monoclonal antibody (mAb). This combination significantly reduces metastatic burden and prolongs the life of mice compared with either monotherapy alone. Importantly, the combination was only effective when the tumor expressed high levels of CD73, suggesting a tumor biomarker that at a minimum could be used to stratify patients that might receive this combination. The mechanism of the combination therapy was critically dependent on NK cells and IFNgamma, and to a lesser extent, CD8(+) T cells and the effector molecule, perforin. Overall, these results provide a strong rationale to use A2ARi with anti-PD-1 mAb for the treatment of minimal residual and metastatic disease.
in vivo blocking of PD-1/PD-L signaling
John, L. B., et al (2013). "Anti-PD-1 antibody therapy potently enhances the eradication of established tumors by gene-modified T cells" Clin Cancer Res 19(20): 5636-5646.
PubMed
PURPOSE: To determine the antitumor efficacy and toxicity of a novel combination approach involving adoptive T-cell immunotherapy using chimeric antigen receptor (CAR) T cells with an immunomodulatory reagent for blocking immunosuppression. EXPERIMENTAL DESIGN: We examined whether administration of a PD-1 blocking antibody could increase the therapeutic activity of CAR T cells against two different Her-2(+) tumors. The use of a self-antigen mouse model enabled investigation into the efficacy, mechanism, and toxicity of this combination approach. RESULTS: In this study, we first showed a significant increase in the level of PD-1 expressed on transduced anti-Her-2 CD8(+) T cells following antigen-specific stimulation with PD-L1(+) tumor cells and that markers of activation and proliferation were increased in anti-Her-2 T cells in the presence of anti-PD-1 antibody. In adoptive transfer studies in Her-2 transgenic recipient mice, we showed a significant improvement in growth inhibition of two different Her-2(+) tumors treated with anti-Her-2 T cells in combination with anti-PD-1 antibody. The therapeutic effects observed correlated with increased function of anti-Her-2 T cells following PD-1 blockade. Strikingly, a significant decrease in the percentage of Gr1(+) CD11b(+) myeloid-derived suppressor cells (MDSC) was observed in the tumor microenvironment of mice treated with the combination therapy. Importantly, increased antitumor effects were not associated with any autoimmune pathology in normal tissue expressing Her-2 antigen. CONCLUSION: This study shows that specifically blocking PD-1 immunosuppression can potently enhance CAR T-cell therapy that has significant implications for potentially improving therapeutic outcomes of this approach in patients with cancer.
in vivo blocking of PD-1/PD-L signaling
van der Werf, N., et al (2013). "Th2 cell-intrinsic hypo-responsiveness determines susceptibility to helminth infection" PLoS Pathog 9(3): e1003215.
PubMed
The suppression of protective Type 2 immunity is a principal factor driving the chronicity of helminth infections, and has been attributed to a range of Th2 cell-extrinsic immune-regulators. However, the intrinsic fate of parasite-specific Th2 cells within a chronic immune down-regulatory environment, and the resultant impact such fate changes may have on host resistance is unknown. We used IL-4gfp reporter mice to demonstrate that during chronic helminth infection with the filarial nematode Litomosoides sigmodontis, CD4(+) Th2 cells are conditioned towards an intrinsically hypo-responsive phenotype, characterised by a loss of functional ability to proliferate and produce the cytokines IL-4, IL-5 and IL-2. Th2 cell hypo-responsiveness was a key element determining susceptibility to L. sigmodontis infection, and could be reversed in vivo by blockade of PD-1 resulting in long-term recovery of Th2 cell functional quality and enhanced resistance. Contrasting with T cell dysfunction in Type 1 settings, the control of Th2 cell hypo-responsiveness by PD-1 was mediated through PD-L2, and not PD-L1. Thus, intrinsic changes in Th2 cell quality leading to a functionally hypo-responsive phenotype play a key role in determining susceptibility to filarial infection, and the therapeutic manipulation of Th2 cell-intrinsic quality provides a potential avenue for promoting resistance to helminths.
in vivo blocking of PD-1/PD-L signaling
Holmgaard, R. B., et al (2013). "Indoleamine 2,3-dioxygenase is a critical resistance mechanism in antitumor T cell immunotherapy targeting CTLA-4" J Exp Med 210(7): 1389-1402.
PubMed
The cytotoxic T lymphocyte antigen-4 (CTLA-4)-blocking antibody ipilimumab results in durable responses in metastatic melanoma, though therapeutic benefit has been limited to a fraction of patients. This calls for identification of resistance mechanisms and development of combinatorial strategies. Here, we examine the inhibitory role of indoleamine 2,3-dioxygenase (IDO) on the antitumor efficacy of CTLA-4 blockade. In IDO knockout mice treated with anti-CTLA-4 antibody, we demonstrate a striking delay in B16 melanoma tumor growth and increased overall survival when compared with wild-type mice. This was also observed with antibodies targeting PD-1-PD-L1 and GITR. To highlight the therapeutic relevance of these findings, we show that CTLA-4 blockade strongly synergizes with IDO inhibitors to mediate rejection of both IDO-expressing and nonexpressing poorly immunogenic tumors, emphasizing the importance of the inhibitory role of both tumor- and host-derived IDO. This effect was T cell dependent, leading to enhanced infiltration of tumor-specific effector T cells and a marked increase in the effector-to-regulatory T cell ratios in the tumors. Overall, these data demonstrate the immunosuppressive role of IDO in the context of immunotherapies targeting immune checkpoints and provide a strong incentive to clinically explore combination therapies using IDO inhibitors irrespective of IDO expression by the tumor cells.
in vivo blocking of PD-1/PD-L signaling
Curran, M. A., et al (2010). "PD-1 and CTLA-4 combination blockade expands infiltrating T cells and reduces regulatory T and myeloid cells within B16 melanoma tumors" Proc Natl Acad Sci U S A 107(9): 4275-4280.
PubMed
Vaccination with irradiated B16 melanoma cells expressing either GM-CSF (Gvax) or Flt3-ligand (Fvax) combined with antibody blockade of the negative T-cell costimulatory receptor cytotoxic T-lymphocyte antigen-4 (CTLA-4) promotes rejection of preimplanted tumors. Despite CTLA-4 blockade, T-cell proliferation and cytokine production can be inhibited by the interaction of programmed death-1 (PD-1) with its ligands PD-L1 and PD-L2 or by the interaction of PD-L1 with B7-1. Here, we show that the combination of CTLA-4 and PD-1 blockade is more than twice as effective as either alone in promoting the rejection of B16 melanomas in conjunction with Fvax. Adding alphaPD-L1 to this regimen results in rejection of 65% of preimplanted tumors vs. 10% with CTLA-4 blockade alone. Combination PD-1 and CTLA-4 blockade increases effector T-cell (Teff) infiltration, resulting in highly advantageous Teff-to-regulatory T-cell ratios with the tumor. The fraction of tumor-infiltrating Teffs expressing CTLA-4 and PD-1 increases, reflecting the proliferation and accumulation of cells that would otherwise be anergized. Combination blockade also synergistically increases Teff-to-myeloid-derived suppressor cell ratios within B16 melanomas. IFN-gamma production increases in both the tumor and vaccine draining lymph nodes, as does the frequency of IFN-gamma/TNF-alpha double-producing CD8(+) T cells within the tumor. These results suggest that combination blockade of the PD-1/PD-L1- and CTLA-4-negative costimulatory pathways allows tumor-specific T cells that would otherwise be inactivated to continue to expand and carry out effector functions, thereby shifting the tumor microenvironment from suppressive to inflammatory.
Product Citations
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Immunology and Microbiology
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Cancer Research
Potential treatment benefits of a GLP-1R antagonist in combination with immune checkpoint inhibitors in colorectal cancer.
In Oncol Lett on 1 April 2026 by Zhan, Z., Zhan, C., et al.
PubMed
The clinical efficacy of immune checkpoint inhibitors (ICIs) in colorectal cancer (CRC) remains limited. Modulation of the glucagon-like peptide-1 receptor (GLP-1R) may enhance T-cell-mediated antitumor responses. The present study aimed to evaluate the antitumor effects of the GLP-1R antagonist Exendin 9-39 (Exe-9) combined with anti-programmed cell death protein-1 (PD-1) treatment in preclinical CRC models. Using in vitro co-culture assays, ELISA and in vivo murine models, alongside immunohistochemical and molecular analyses of clinical samples, HT-29 and MC38-OVA colon cancer cell lines were co-cultured in vitro with activated T cells in the presence of Exe-9. In vivo, male BALB/c mice were injected with MC38 to establish a CRC model and nude mice were used to assess T-cell dependency. To evaluate this synergistic effect, BALB/c mice with CRC were treated with Exe-9, anti-PD-1 or a combination. Additionally, clinical CRC samples were analyzed to assess the association of GLP-1R expression with the immunotherapy response. Exe-9 significantly enhanced T-cell-mediated cytotoxicity in CRC cell lines and reduced tumor growth in immunocompetent CRC mice; however, this effect was not observed in nude mice. Furthermore, combination therapy with the GLP-1R antagonist and anti-PD-1 yielded an improved antitumor effect compared with either treatment alone, and high GLP-1R ex2pression in clinical samples correlated with poor ICI response. These findings suggest that GLP-1R antagonism potentiates T-cell-mediated antitumor immunity and may provide a promising adjunctive therapeutic strategy for patients with CRC when combined with ICIs in the future.
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Cancer Research
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Immunology and Microbiology
GITR activation potentiates anti-tumor immunity of tumor-infiltrating lymphocytes expanded from glioblastoma by rescuing exhaustion.
In Oncogene on 1 April 2026 by Zhou, J., Yang, Y., et al.
PubMed
Autologous tumor-infiltrating lymphocyte (TIL) therapy holds transformative potential for solid tumors, yet its efficacy in glioblastoma remains limited by T cell exhaustion and immunosuppression. In the current study, we optimized an effective and reliable method for in vitro expansion of TILs from glioblastoma lesions and assessed their tumor-killing capacity both in vitro and in vivo. Single-cell RNA sequencing (scRNA-seq) of expanded TILs uncovered their heterogeneity and identified a cytotoxic tissue-resident memory (TRM) CD8+ TIL subset with a unique exhaustion signature. Notably, the co-stimulatory factor GITR (encoded by TNFRSF18) is highly expressed not only on immunosuppressive regulatory T (Treg) cells but also on exhausted CD8+ TILs. GITR agonism via αGITR antibody achieved dual effects: it directly enhanced CD8+ TIL activation while simultaneously abrogating Treg-mediated immunosuppression. This dual-action mechanism synergized with αPD-1 therapy to amplify TIL reactivation, significantly enhancing tumor control in vivo. Mechanistically, GITR activation potentiated anti-tumor responses by promoting immunological synapse (IS) formation and function in TILs via the NF-κB/KALRN signaling axis. Our findings established GITR as a crucial regulator of CD8+ TIL anti-tumor immunity, positioning GITR targeting as a novel strategy to improve TIL therapy for glioblastoma, with promising implications for clinical application.
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Cancer Research
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Immunology and Microbiology
NEK8 kinase-mediated lactate increase impairs antitumor immunity decreasing radiotherapy sensitivity in colorectal cancer.
In Nat Commun on 28 March 2026 by Li, M., Ni, Y., et al.
PubMed
Radiotherapy effectively treats colorectal cancer (CRC), but local recurrence remains common and abscopal effects-regression of tumors distant from irradiated sites-are rarely observed even with immune checkpoint inhibitors. Here we show that the protein kinase NEK8, highly expressed in CRC, promotes radioresistance by suppressing anti-tumor immunity. In radiation-resistant tumors, NEK8 phosphorylates lactate dehydrogenase A (LDHA), driving lactate overproduction. This metabolite promotes histone modifications that silence antigen presentation machinery, while extracellular lactate directly impairs CD8+ T cell function, collectively excluding CD8+ T cell from the tumor microenvironment. Pharmacological inhibition of NEK8 using CX6258 restores CD8+ T cell infiltration and enhances both local and systemic tumor control following radiotherapy. These findings establish NEK8 as a promising therapeutic target for overcoming radioresistance and inducing abscopal responses in CRC.
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Cancer Research
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Immunology and Microbiology
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Western Blotting
Inhibition of RAB7 promotes CD8+ T cell activation via the STING/IRF1/CCL5/CXCL10 signaling axis to promote PD-1-mediated anti-lung cancer efficacy.
In Am J Cancer Res on 23 March 2026 by Liu, X., Jiang, Z., et al.
PubMed
Programmed cell death protein 1 (PD-1) antibody is facing the challenge of drug resistance in cancer therapy. RAB7 plays a key role in autophagic lysosomal fusion, but its function in tumor immune regulation, especially whether it can enhance the efficacy of PD-1 inhibitors, is not clear. RAS-associated binding protein 7 (RAB7) and stimulator of interferon gene (STING) were knocked down by siRNA in lung squamous cell carcinoma (LUSC) cells. The effects of RAB7 and STING on the malignant phenotype of cells were evaluated. The autophagy flux and cytoplasmic double-stranded DNA (dsDNA) accumulation were observed by Western blot, RFP-GFP-LC3B tandem fluorescent probe, transmission electron microscopy and immunofluorescence. The expression of STING/interferon regulatory factor 1 (IRF1) pathway was analyzed by Western blot. CD8+ T cells were co-cultured with lung cancer cells to investigate RAB7 knockdown effects on CD8+ T cell activation. Finally, mouse subcutaneous xenograft models were established to explore RAB7 knockdown combined with anti-PD-1 treatment. RAB7 was highly expressed in lung cancer, and its knockdown blocked autophagy flux, leading to cytoplasmic dsDNA accumulation, which in turn activated the STING/IRF1 signaling axis and up-regulated C-C motif chemokine ligand 5 (CCL5) and C-X-C motif chemokine ligand (CXCL) 10. In the co-culture system, knockdown of RAB7 promoted CD8+ T cell proliferation and cytotoxicity, up-regulated Perforin expressions, and decreased the levels of PD-1 and CD39. The combined application inhibited tumor growth, which was accompanied by activation of STING/IRF1 pathway, increased tumor infiltration and CD8+ T cell function. STING knockdown reversed all anti-tumor and immune activation effects mediated by RAB7 knockdown. In summary, knockdown of RAB7 activated the STING/IRF1/CCL5/CXCL10 signaling pathway by blocking autophagy flux, enhanced the activation and infiltration of CD8+ T cells, and significantly enhanced PD-1 antibody efficacy against lung cancer.
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Cancer Research
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Immunology and Microbiology
Characterization of HER2-Positive Murine Breast Cancer Models for Investigating HER2-Targeted Therapy and Immunotherapy.
In Cancers (Basel) on 19 March 2026 by Lu, Y., Lee, B. P., et al.
PubMed
Background/Objectives: Human epidermal growth factor receptor 2 (HER2)-positive breast cancer is linked to poorer overall survival and a higher risk of brain metastases compared to HER2-negative breast cancer. Current preclinical studies lack robust HER2+ metastatic syngeneic mouse models for investigating targeted and immunomodulatory therapies. This study aims to develop effective HER2+ mouse models to investigate response dynamics to HER2-targeted therapy and immunotherapy. Methods: The human HER2 gene (WT or mutant p.A775_G776insYVMA, GFP-tagged at the C-terminus) was introduced into triple-negative breast cancer (TNBC) mouse mammary carcinoma cells with known metastatic potential (4T1 and EO771) via lentiviral transduction. HER2 expression and phosphorylation were analyzed using Western blotting and immunohistochemistry. Tumors were treated with HER2-targeted therapy (trastuzumab and tucatinib), immune checkpoint blockade (anti-PD-1 and anti-CTLA-4), and anti-HER2 antibody-drug conjugate (ADC) to evaluate treatment efficacy. Metastatic potential was assessed with brain fluorescence imaging. Statistical analysis included ANOVA and Kaplan-Meier tests. Results: Newly established lines demonstrated expression of HER2+, with HER2YVMA lines showing higher phosphorylation than HER2WT lines. Cells were tumorigenic, demonstrating in vivo tumor take rates at 100% for 4T1-HER2 and 15-30% for EO771-HER2. HER2 overexpression led to a 30% increase in spontaneous brain metastasis in the 4T1-HER2 models. Trastuzumab alone did not reduce primary tumor size but significantly reduced brain GFP signal by 17% ± 8% and 26% ± 7% in the 4T1-HER2WT and 4T1-HER2YVMA models, respectively. Combinational therapies with anti-HER2 therapy and immune checkpoint blockade effectively suppressed primary tumor growth and prolonged survival in EO771-HER2YVMA model. T-Dxd, but not T-DM1, demonstrated partial treatment response in the EO771-HER2WT model. Conclusions: HER2+ syngeneic tumor models were developed that spontaneously metastasize to the brain and demonstrate variable responses to immunotherapies and ADCs. These models are valuable for advancing molecular imaging modalities for HER2+ brain metastasis, studying blood-brain barrier penetration of HER2-targeted drugs, and exploring the combination of therapies, including immunotherapy.
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Immunology and Microbiology
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Cancer Research
Mismatch repair deficiency drives malignant progression and alters the tumor immune microenvironment in glioblastoma models.
In J Clin Invest on 16 March 2026 by Puigdelloses Vallcorba, M., Soni, N., et al.
PubMed
Mutations in DNA mismatch repair (MMR) pathway genes (MSH2, MSH6, MLH1, and PMS2) are linked to acquired resistance to temozolomide (TMZ) and high tumor mutation burden (TMB) in high-grade gliomas (HGGs), including glioblastomas (GBMs). However, the specific roles of individual MMR genes in the initiation, progression, TMB, microsatellite instability (MSI), and resistance to TMZ in gliomas remain unclear. Here, we developed de novo mouse models of germline and somatic MMR-deficient (MMRd) HGGs. Surprisingly, loss of Msh2 or Msh6 did not lead to high TMB, MSI, nor did it confer a response to anti-programmed cell death 1 (anti-PD-1) in GBM. Similarly, human GBM showed discordance between MMR gene mutations and the TMB and MSI. Germline MMRd promoted the progression from low-grade to HGG and reduced survival compared with MMR-proficient (MMRp) tumor-bearing mice. This effect was not tumor cell intrinsic but was associated with MMRd in the tumor immune microenvironment, driving immunosuppressive myeloid programs, reduced lymphoid infiltration, and CD8+ T cell exhaustion. Both MMR-reduced (MMRr) and MMRd GBM were resistant to TMZ, unlike MMRp tumors. Our study shows that N3-(2-fluoroethyl) imidazotetrazine (KL-50), an imidazotetrazine-based DNA targeting agent that induces MMR-independent cross-link-mediated cytotoxicity, was effective against germline and somatic MMRr and MMRd GBMs, offering a potential therapy for TMZ-resistant HGG with MMR alterations.
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Cancer Research
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Immunology and Microbiology
A CD138+ tumor-associated macrophage-Siglec-F+ neutrophil feedforward loop promotes immune evasion in pancreatic cancer.
In J Clin Invest on 12 March 2026 by Wang, C., Zhang, Q., et al.
PubMed
Immune evasion is a major obstacle ahead of pancreatic cancer therapy. Recent data implicate pro-inflammatory macrophages in the progression of pancreatic ductal adenocarcinoma (PDAC) and its therapeutic response. However, whether or which of the pro-inflammatory macrophage subtypes play a crucial role in the immune escape of PDAC remains unclear. Here we identify a population of CD138+ tumor-associated macrophages (TAMs), characterized by their pro-inflammatory and neutrophil-chemotactic activity, which undergo significant expansion in both PDAC patients and mouse models. These cells are elicited by a local synergy between IL-34-syndecan-1 and PGE2-EP2 signaling and are associated with immune evasion and poor clinical outcomes in patients, while also promoting immune escape and disease progression in mouse models. Mechanistically, CD138+ TAMs establish a feedforward loop with immunosuppressive Siglec-F+ neutrophils, which exhibit elevated PGE2 expression, via the secretion of Saa3 and Cxcl1. Targeting CD138+ TAMs by disrupting IL-34-syndecan-1 signaling with anti-IL-34 neutralizing antibodies significantly suppresses PDAC progression, especially when combined with anti-PD-1 antibodies. Together, our study elucidates a CD138+ TAM-Siglec-F+ neutrophil axis that drives immune escape in PDAC and proposes a therapeutic strategy that integrates IL-34-syndecan-1 signaling blockade with anti-PD-1 immunotherapy for the treatment of PDAC.
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Cell Biology
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Immunocytochemistry-immunofluorescence
Peritumoural adipose tissue promotes ferroptosis resistance by 3-hydroxykynurenine-mediated suppression of ferritinophagy.
In Nat Cell Biol on 11 March 2026 by Zhang, Y. Y., Han, Y., et al.
PubMed
The peritumoural adipose tissue (PAT) is a key contributor to cancer therapy resistance, yet its role in regulating ferroptosis remains unclear. Here we demonstrate that PAT confers ferroptosis resistance to cancer cells by upregulating ferritin (FTH1/FTL) and sequestering intracellular iron. PAT-derived kynurenine (KYN) was identified as the principal mediator. KYN is taken up by cancer cells and metabolized to 3-hydroxykynurenine, which directly binds to nuclear receptor coactivator 4 (NCOA4). This interaction inhibits NCOA4-mediated ferritinophagy, preventing ferritin degradation and limiting the free iron pool required for ferroptosis. In murine models, pharmacological inhibition of the KYN pathway synergized with PD-1 blockade to overcome ferroptosis resistance and suppress tumour progression. These findings reveal a PAT-KYN-ferritinophagy axis that promotes ferroptosis resistance, highlighting the potential of targeting adipose-tumour cross-talk to enhance immunotherapy in PAT-associated tumours.
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Cell Biology
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Immunohistochemistry
Peritumoural adipose tissue promotes ferroptosis resistance by 3-hydroxykynurenine-mediated suppression of ferritinophagy.
In Nat Cell Biol on 11 March 2026 by Zhang, Y. Y., Han, Y., et al.
PubMed
The peritumoural adipose tissue (PAT) is a key contributor to cancer therapy resistance, yet its role in regulating ferroptosis remains unclear. Here we demonstrate that PAT confers ferroptosis resistance to cancer cells by upregulating ferritin (FTH1/FTL) and sequestering intracellular iron. PAT-derived kynurenine (KYN) was identified as the principal mediator. KYN is taken up by cancer cells and metabolized to 3-hydroxykynurenine, which directly binds to nuclear receptor coactivator 4 (NCOA4). This interaction inhibits NCOA4-mediated ferritinophagy, preventing ferritin degradation and limiting the free iron pool required for ferroptosis. In murine models, pharmacological inhibition of the KYN pathway synergized with PD-1 blockade to overcome ferroptosis resistance and suppress tumour progression. These findings reveal a PAT-KYN-ferritinophagy axis that promotes ferroptosis resistance, highlighting the potential of targeting adipose-tumour cross-talk to enhance immunotherapy in PAT-associated tumours.
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Immunology and Microbiology
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Cancer Research
HKDC1-Mediated Polyamine Rewiring Drives Lenvatinib Resistance and Immune Escape in Hepatocellular Carcinoma.
In Clin Mol Hepatol on 11 March 2026 by Chen, S., Wang, B., et al.
PubMed
Lenvatinib resistance and immune exclusion limit outcomes in HCC. We hypothesized that metabolic rewiring orchestrates resistance to lenvatinib and PD-1 blockade.
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Cancer Research
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Immunology and Microbiology
B cells disrupt tertiary lymphoid structure formation and suppress anti-tumor immunity.
In Cancer Cell on 9 March 2026 by Chen, C., An, M., et al.
PubMed
Tertiary lymphoid structures (TLSs) promote antigen-specific anti-tumor immunity, but the regulators of TLSs homeostasis in cancer remain unclear. Using single-cell RNA-sequencing and spatial transcriptomics, we identify an IGLL5+ B cell subset in bladder cancer (BCa). In genetically engineered and humanized mouse models, these IGLL5+ B cells disrupt TLS's integrity and impair immunotherapy responses. Mechanistically, IGLL5+ B cells bind high endothelial venules (HEVs) via IGLL5-LTβR ligand-receptor interactions, with IGLL5 inducing a conformational change in LTβR that inhibits non-canonical NF-κB signaling, leading to TLSs disassembly. Clinically, blocking IGLL5 preserves TLSs and enhances immunotherapy efficacy in patient-derived xenograft (PDX) and pan-cancer models. Our findings suggest that targeting IGLL5+ B cells offers a promising strategy to boost TLS-dependent cancer immunotherapy.
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Cancer Research
Nintedanib enhances the antitumor efficacy of pd-1 blockade, potentially through inhibition of myeloid-derived suppressor cells and cancer-associated fibroblasts.
In Cancer Immunol Immunother on 5 March 2026 by Suzuki, R., Watanabe, S., et al.
PubMed
Although programmed cell death-1 (PD-1) inhibitors have shown promising and durable responses in patients with several types of cancer, many patients show resistance to PD-1 inhibitors. Recent evidence has demonstrated that immunosuppressive cells are induced in tumor microenvironment and inhibit the anti-tumor effects of anti-PD-1 monoclonal antibody (αPD-1 mAb). To investigate whether nintedanib-a multi-tyrosine kinase inhibitor targeting vascular endothelial growth factor receptor, fibroblast growth factor receptor, and platelet-derived growth factor receptor-suppresses immunosuppressive cells and enhances the anti-tumor effects of αPD-1 mAb in preclinical models, flowcytometry, immunohistochemistry, and RNA sequencing of tumor-tissue, tumor-draining lymph nodes, spleens were conducted. RNA sequencing of murine tumor tissues revealed that nintedanib decreased the gene signatures related to myeloid-derived suppressor cells (MDSCs) and cancer-associated fibroblasts (CAFs). Flow cytometry showed that nintedanib significantly decreased the MDSC and CAF percentage in tumor-bearing hosts and increased IFN-ϒ+CD4+ and CD8+ T cells infiltrating into tumors. Immunohistochemical analysis demonstrated that nintedanib treatment significantly increased the number of CD8+ T cells in the internal area of the tumor. Adding nintedanib to anti-PD-1 mAb therapy significantly inhibited in vivo tumor progression. These results indicate that nintedanib suppresses MDSCs and CAFs by inhibiting VEGFR-, PDGFR-, and FGFR-mediated signaling, thereby increasing effector T-cell infiltration into tumors and enhancing the anti-tumor effects of αPD-1 mAb therapy.
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Immunology and Microbiology
T-cell Priming by High-Avidity Neoantigens in Lymph Nodes Augments Adoptive Immunotherapy.
In Cancer Immunol Res on 4 March 2026 by Wittling, M. C., Rivera Reyes, A. M., et al.
PubMed
Adoptive transfer of T lymphocytes specific for neoantigens can elicit immunity against solid tumors in patients. However, how these antigens affect T-cell function, effector differentiation, and persistence remains unclear. We examined how an identical CD8+ T-cell product was shaped by melanoma expressing either a low-avidity self/tumor-associated antigen or high-avidity neoantigen and kinetically profiled T-cell differentiation in these two contexts across host tissues. High-avidity neoantigen expression was sufficient to activate naïve CD8+ T cells-leading to robust tumor regression and long-term protective immunity upon tumor rechallenge. Mechanistically, transferred naïve CD8+ T cells reacting to high-avidity neoantigen exhibited enhanced cytokine production, heightened effector function, and sustained persistence compared with the low-avidity wild-type tumors. Antitumor activity to these high-avidity tumors was preserved even in the absence of functional host T and B lymphocytes, and early lymph node (LN) trafficking was found to be essential for adoptive T-cell therapy efficacy. Expanded effector or stem memory T cells were compared with the naïve pmel-1 T-cell product. Stem memory (but not effector memory) cells exhibited similar antitumor efficacy and LN trafficking patterns to the naïve cells in mice with high-avidity neoantigen-expressing tumors. These findings highlight how differential tumor antigens shape divergent cellular fate and uncover a critical role of T-cell trafficking in LNs in shaping high-avidity neoantigen-specific responses.
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Immunology and Microbiology
A glucocorticoid-FAS axis controls immune evasion during metastatic seeding.
In Nature on 4 March 2026 by Cassandras, M., Sánchez, X., et al.
PubMed
Metastasis is the major cause of death for patients with triple-negative breast cancer and other solid malignancies. Metastases arise from cancer cells that disseminate from the original tumour, survive systemic immune surveillance and colonize new organs1. Little is known about how initial disseminated tumour cells (DTCs) overcome anti-tumour immunity after seeding a new organ. Here we use a visible antigen in a model of triple-negative breast cancer with cognate CD8+ T cells to study the mechanisms of immune evasion in early metastatic seeding. Analysis of surviving DTCs revealed glucocorticoid receptor (GR) activation as a key driver of resistance to both CD8+ T cells and natural killer cells. Niche profiling using an optimized labelling tool identified FAS-FASL as a key pan-cytotoxic pathway against DTCs, which is repressed by GR activation. Pharmacological inhibition of GR in combination with immunotherapy reduced metastatic burden and expanded lifespan in mice. Thus, we identified a mechanism of immune evasion that operates specifically in DTCs, illustrating the unique immune-cancer interactions at this stage in the metastatic cascade. Our findings suggest that there are therapeutic opportunities to eliminate DTCs, separately from treatments aimed at primary tumours, and GR inhibition is one promising target.
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Biochemistry and Molecular biology
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Genetics
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Immunology and Microbiology
Uridine depletion impairs CD8⁺ T cell antitumor activity through N-glycosylation.
In Cell Metab on 3 March 2026 by Xiao, J., Li, Z., et al.
PubMed
Immune checkpoint blockade (ICB) faces limitations owing to high cost and restricted efficacy. This study identifies SNX17 as a key mediator of ICB resistance. Elevated SNX17 correlates with poor anti-PD-1 response in humans and mice. SNX17 deletion in tumor cells inhibits tumor growth via CD8+ T cell-dependent mechanisms. SNX17 reduces uridine in the tumor microenvironment (TME), suppressing IFN-γ and upregulating PD1 in CD8+ T cells. Exogenous uridine shows antitumor efficacy comparable to anti-PD-1/PD-L1 in low-SNX17 tumors and overcomes resistance in high-SNX17 models. Uridine enhances CD8+ T cell function by promoting CD45 N-glycosylation and LCK phosphorylation. Mechanistically, SNX17 stabilizes RUNX2, promoting UPP1 transcription and uridine degradation in the TME. These findings position SNX17 as an ICB response biomarker and nominate uridine as a cost-effective immunotherapeutic strategy.
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Pharmacology
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Immunology and Microbiology
ACT001 synergizes with temozolomide-based chemoradiotherapy to cure refractory glioblastoma by targeting TNF-CXCL10-CD8+ T-cell immunity.
In Front Pharmacol on 2 March 2026 by Shu, Y., Ding, Z. H., et al.
PubMed
Glioblastoma multiforme (GBM), a highly invasive brain tumor, is severely restricted in T-cell infiltration and anti-tumor activity due to its immunosuppressive microenvironment. However, commonly used preclinical GBM mouse models cannot fully recapitulate the refractoriness of human GBM or effectively distinguish therapeutic efficacy. In this study, we evaluated the efficacy and mechanisms of therapies based on the novel sesquiterpene lactone small-molecule compound, ACT001, using the refractory G422TN-GBM mouse model. ACT001 alone exerted evident anti-G422TN-GBM effects in vivo and in vitro, but it only slightly prolonged animal survival. ACT001 combined with concurrent radiotherapy and temozolomide (RT/TMZ) exerted synergistic effects by suppressing tumor progression and extending animal survival. Importantly, the RT/TMZ/ACT001 regimen could achieve cure (long-term survival, >100 d, 26.7%) and immune cure (passing the tumor-rechallenge assay, >100 d, 12.5%) in G422TN mice. However, combining the anti-PD-1 antibody (αPD-1) with RT/TMZ/ACT001 did not further improve survival. Mechanistically, RT/TMZ/ACT001 substantially activated the tumor necrosis factor (TNF) pathway, inducing tumor cells and stromal cells in the microenvironment to express the chemokine C-X-C motif chemokine 10 (CXCL10), thereby promoting T-cell infiltration, especially CD8+ T cell, into the tumor site. Pharmacological inhibition of the TNF signaling pathway with R-7050 completely abolished the synergistic efficacy of RT/TMZ/ACT001. Taken together, our results demonstrate that ACT001 combined with RT/TMZ can overcome the immunosuppressive barrier of GBM to achieve immune cure in GBM via TNF-CXCL10-CD8+ signaling, strongly suggesting the priority of combining ACT001 with RT/TMZ rather than with αPD-1 in clinical trials.
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Cancer Research
Activated ATF6α is a hepatic tumour driver restricting immunosurveillance.
In Nature on 1 March 2026 by Li, X., Lebeaupin, C., et al.
PubMed
Hepatocellular carcinoma (HCC) is the fastest growing cause of cancer-related mortality and there are limited therapies1. Although endoplasmic reticulum (ER) stress and the unfolded protein response (UPR) are implicated in HCC, the involvement of the UPR transducer ATF6α remains unclear2. Here we demonstrate the function of ATF6α as an ER-stress-inducing tumour driver and metabolic master regulator restricting cancer immunosurveillance for HCC, in contrast to its well-characterized role as an adaptive response to ER stress3. ATF6α activation in human HCC is significantly correlated with an aggressive tumour phenotype, characterized by reduced patient survival, enhanced tumour progression and local immunosuppression. Hepatocyte-specific ATF6α activation in mice induced progressive hepatitis with ER stress, immunosuppression and hepatocyte proliferation. Concomitantly, activated ATF6α increased glycolysis and directly repressed the gluconeogenic enzyme FBP1 by binding to gene regulatory elements. Restoring FBP1 expression limited ATF6α-activation-related pathologies. Prolonged ATF6α activation in hepatocytes triggered hepatocarcinogenesis, intratumoural T cell infiltration and nutrient-deprived immune exhaustion. Immune checkpoint blockade (ICB)4 restored immunosurveillance and reduced HCC. Consistently, patients with HCC who achieved a complete response to immunotherapy displayed significantly increased ATF6α activation compared with those with a weaker response. Targeting Atf6 through germline ablation, hepatocyte-specific ablation or therapeutic hepatocyte delivery of antisense oligonucleotides dampened HCC in preclinical liver cancer models. Thus, prolonged ATF6α activation drives ER stress, leading to glycolysis-dependent immunosuppression in liver cancer and sensitizing to ICB. Our findings suggest that persistently activated ATF6α is a tumour driver, a potential stratification marker for ICB response and a therapeutic target for HCC.
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Cell Biology
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Immunology and Microbiology
Dynamic magneto-mechanical force in lysosomes induces durable macrophage repolarization for antitumor immunity.
In Cell Res on 1 March 2026 by Li, Y., Zheng, M., et al.
PubMed
Mechanical forces are emerging physical cues that regulate biochemical signals of immune cells for antitumor immunity. Owing to the lack of precise tools to impose intracellular forces, little is known about whether and how organelle-level forces trigger mechanotransduction for antitumor immunity. Here, we developed a magneto-mechanical force-triggered lysosomal membrane permeabilization (MagLMP) strategy to induce durable macrophage repolarization for in vivo applications. Self-assembled magnetic nanomotors are driven by rotational magnetic fields, facilitating dynamic damage to the lysosomal membrane by a finely tuned torque-induced vortex. Intriguingly, galectin 9 (Gal9) was found to be critical for sensing cyclic MagLMP, which dynamically activated AMP-activated protein kinase (AMPK), enhanced activation of nuclear factor kappa B (NF-κB), and induced metabolic alterations for sustained M1-like macrophage repolarization, followed by mounting of antitumor immunity. Through single-cell RNA sequencing of tumor tissues, as well as macrophage depletion-reconstitution models involving intratumoral transfer of Gal9-KO bone marrow-derived macrophages (BMDMs) and AMPK shRNA-transduced Gal9-KO BMDMs, we confirmed the Gal9-AMPK-NF-κB axis as the essential pathway by which MagLMP functions in antitumor therapy. In a mouse model of lung adenocarcinoma in situ, overall survival was extended after intravenous administration of nanomotors followed by cyclic MagLMP, and one third of mice survived for more than 300 days. Together, these results demonstrate an intracellular mechanical strategy that can dynamically manipulate innate immune responses in vivo, providing a tool for durable immunotherapy through organelle mechanotransduction.
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Cancer Research
PD-1 inhibitor improves radiosensitivity by tumor vessel normalization.
In Br J Cancer on 1 March 2026 by Hao, S., Ai, D., et al.
PubMed
Host immunity status and hypoxia are the hallmarks of radiosensitivity. Induction of anti-PD-1 immunotherapy demonstrates promise in locally advanced tumor radiotherapy, but whether anti-PD-1 immunotherapy improves radiosensitivity is unclear.
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Cancer Research
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Cell Biology
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Immunology and Microbiology
Peritumoural adipose tissue drives immune evasion in colorectal cancer via adipose-mesenchymal transformation.
In Nat Cell Biol on 1 March 2026 by Wang, J. H., Zheng, Y., et al.
PubMed
Although peritumoural visceral adipose tissue (tVAT) is anatomically close to tumours such as colorectal cancer, the immune landscape of this tissue and its functional contribution to tumour immunity remain poorly defined. Here, we performed single-cell RNA analysis on the tVAT from patients with colorectal cancer to map its immune landscape and observed that tVAT exhibited a highly immune-infiltrated microenvironment enriched with lymphocytes, especially tumour-specific CD8⁺ T cells. Mechanistically, tVAT competes with the tumour for these immunocytes by activating the CXCL12-CXCR4 axis to promote tumour immune escape. Moreover, tumour-derived factors induce an adipose-mesenchymal transformation process where the adipose stromal cells trans-differentiated into adipose-derived cancer-associated fibroblasts, which secrete large amounts of CXCL12 in tVAT. Clinically, targeting adipose-tumour interaction substantially enhances diagnostic and therapeutic efficacy of anti-PD-1 therapy. These findings offer an understanding of the dynamic crosstalk between tVAT and tumour immune escape, highlighting the tVAT as a potential target for cancer immunotherapy.
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