InVivoSIM anti-human PD-1 (Pembrolizumab Biosimilar)

Hepatocellular carcinoma (HCC) is one of the most fatal tumours worldwide and has a high recurrence rate. Nevertheless, the mechanism of HCC genesis remains partly unexplored, while the efficiency of HCC treatments remains limited. The present study analysed the expression of nuclear receptor subfamily 4 group A member 1 (NR4A1) in tumour-infiltrating natural killer (NK) cells derived from both human patients with HCC and tumour-bearing mouse models, as well as the features of NR4A1high and NR4A1low NK cells. In addition, knockout of NR4A1 by CRISPR/Cas9 and adoptive transfer experiments were applied to verify the function of NR4A1 in both tumour-infiltrating NK cells and anti-PD-1 therapy. The present study found that NR4A1 was significantly highly expressed in tumour-infiltrating NK cells, which mediated the dysfunction of tumour-infiltrating NK cells by regulating the IFN-γ/p-STAT1/IRF1 signalling pathway. Knockout of NR4A1 in NK cells not only restored the antitumour function of NK cells but also enhanced the efficacy of anti-PD-1 therapy. The present findings suggest a regulatory role of NR4A1 in the immune progress of NK cells against HCC, which may provide a new direction for immunotherapies of HCC.

The efficacy of an immune checkpoint blockade has been demonstrated against various types of cancer, but its suitability has not been fully proven for therapies specifically targeting sarcoma. We conducted a pan-cancer tumor data analysis to identify key immune-related variables strongly associated with sarcoma prognosis, and we explored whether these expected factors are functionally correlated with anti-PD-1 therapy in humanized (Hu) NOD.Cg-Prkdc^scidIl2rg^tm1Wjl/SzJ (NSG) mice xenografted with dedifferentiated liposarcoma (DDLPS). We found that an abundance of hCD8⁺ T cells and hNK cells was functionally associated with anti-PD-1 effects in the Hu-NSG DDLPS mice. Phenotypically, these cells were shown to be hCD8⁺IFNγ⁺, hCD8⁺PD-1⁺, hCD8⁺Ki-67⁺, hCD56⁺IFNγ⁺, hCD56⁺PD-1⁺, and hCD56⁺Ki-67⁺ cells and were enriched in splenocytes and tumor-infiltrating lymphocytes (TILs) of Hu-NSG DDLPS mice treated with anti-PD-1 antibody. Moreover, a considerable increase in activated hCD56⁺NKp46⁺NKG2D⁺ NK cells was also detected. Our findings suggest that hCD8⁺ T and hNK subsets play a pivotal role in anti-DDLPS tumor effects of anti-PD-1 therapy. The results provide clinical reference for advanced anti-PD-1 therapy targeting sarcoma tumors including DDLPS.

Background: Immunotherapy has significantly advanced cancer treatments, but many patients do not respond to it, partly due to immunosuppressive mechanisms used by tumor cells. These cells employ immunosuppressive ligands to evade detection and elimination by the immune system. Therefore, the discovery and characterization of novel immunosuppressive ligands that facilitate immune evasion are crucial for developing more potent anti-cancer therapies. Methods: We conducted gain-of-function screens using a CRISPRa (CRISPR activation) library that covered the entire human transmembrane sub-genome to identify surface molecules capable of hindering NK-mediated cytotoxicity. The immunosuppressive role and mechanism of MUC21 were validated using NK and T cell mediated cytotoxicity assays. Bioinformatics tools were employed to assess the clinical implications of mucin-21 (MUC21) in cancer cell immunity. Results: Our genetic screens revealed that MUC21 expression on cancer cell surfaces inhibits both the cytotoxic activity of NK cells and antibody-dependent cellular cytotoxicity, but not affecting complement-dependent cytotoxicity. Additionally, MUC21 expression hinders T cell activation by impeding antigen recognition, thereby diminishing the effectiveness of the immune checkpoint inhibitor, anti-PD-L1. Moreover, MUC21 expression suppress the antitumor function of both CAR-T cells and CAR-NK cells. Mechanistically, MUC21 facilitates immune evasion by creating steric hindrance, preventing interactions between cancer and immune cells. Bioinformatics analysis revealed elevated MUC21 expression in lung cancer, which correlated with reduced infiltration and activation of cytotoxic immune cells. Intriguingly, MUC21 expression was higher in non-small cell lung cancer (NSCLC) tumors that were non-responsive to anti-PD-(L)1 treatment compared to responsive tumors. Conclusions: These findings indicate that surface MUC21 serves as a potent immunosuppressive ligand, shielding cancer cells from NK and CD8⁺T cell attacks. This suggests that inhibiting MUC21 could be a promising strategy to improve cancer immunotherapy.

Introduction: Solid cancers Myeloid cells are prevalent in solid cancers, but they frequently exhibit an anti-inflammatory pro-tumor phenotype that contribute to the immunosuppressive tumor microenvironment (TME), which hinders the effectiveness of cancer immunotherapies. Myeloid cells' natural ability of tumor trafficking makes engineered myeloid cell therapy an intriguing approach to tackle the challenges posed by solid cancers, including tumor infiltration, tumor cell heterogenicity and the immunosuppressive TME. One such engineering approach is to target the checkpoint molecule PD-L1, which is often upregulated by solid cancers to evade immune responses. Method: Here we devised an adoptive cell therapy strategy based on myeloid cells expressing a Chimeric Antigen Receptor (CAR)-like immune receptor (CARIR). The extracellular domain of CARIR is derived from the natural inhibitory receptor PD-1, while the intracellular domain(s) are derived from CD40 and/or CD3ζ. To assess the efficacy of CARIR-engineered myeloid cells, we conducted proof-of-principle experiments using co-culture and flow cytometry-based phagocytosis assays in vitro. Additionally, we employed a fully immune-competent syngeneic tumor mouse model to evaluate the strategy's effectiveness in vivo. Result: Co-culturing CARIR-expressing human monocytic THP-1 cells with PD-L1 expressing target cells lead to upregulation of the costimulatory molecule CD86 along with expression of proinflammatory cytokines TNF-1α and IL-1β. Moreover, CARIR expression significantly enhanced phagocytosis of multiple PD-L1 expressing cancer cell lines in vitro. Similar outcomes were observed with CARIR-expressing human primary macrophages. In experiments conducted in syngeneic BALB/c mice bearing 4T1 mammary tumors, infusing murine myeloid cells that express a murine version of CARIR significantly slowed tumor growth and prolonged survival. Conclusion: Taken together, these results demonstrate that adoptive transfer of PD-1 CARIR-engineered myeloid cells represents a promising strategy for treating PD-L1 positive solid cancers.