InVivoMAb human IgG1 isotype control

Cuproptosis is a recently identified form of copper-dependent cell death that depends on ferredoxin 1 (FDX1)-mediated protein lipoylation. Here, we reveal that CD8+ T cell-mediated antitumor immunity enhances tumor cell susceptibility to cuproptosis, leading to a more potent tumor-suppressive effect of cuproptosis inducers in immunocompetent hosts compared with immunodeficient ones. Mechanistically, cuproptotic tumor cells act as a form of immunogenic cell death, releasing damage-associated molecular patterns that activate dendritic cells and enhance antitumor immunity. Reciprocally, CD8+ T cell-derived interferon (IFN)-γ enhances FDX1 transcription in tumor cells by activating the signal transducer and activator of transcription 1 (STAT1)-IFN regulatory factor-1 (IRF1) signaling axis, resulting in heightened tumor cell sensitivity to cuproptosis. Consequently, combining a cuproptosis inducer with anti-programmed cell death ligand 1 (PD-L1) therapy amplifies tumoral cuproptosis and demonstrates efficacy in overcoming PD-L1 therapy resistance across multiple preclinical models. Our findings unveil a previously unrecognized connection between antitumor immunity and cuproptosis and highlight a potential therapeutic approach to counteract tumor immunotherapy resistance by targeting this unique cell death pathway.

Mucinous colorectal carcinoma (MUC CRC) metastasis to multiple organs, and to the peritoneum, is associated with poor prognosis. Disseminating MUC CRCs exhibit either conventional (apical-in) or inverted (apical-out) polarity that influence patient outcomes. Therefore, it is critical to identify how MUC CRC polarity is regulated. Here, we analyze patient-derived MUC CRC xenografts with either apical-in or apical-out polarity. Single-cell analyses reveal α2β1-integrin as a key collagen-binding receptor in these models. Collagen-α2β1-integrin interaction activates Src and upregulates SorLA, an endosomal sorting receptor. SorLA supports apical-in polarity by promoting integrin recycling and HER2/HER3 expression. We observe positive correlation between HER2, HER3 and SorLA in patient samples and higher HER2 expression in apical-in-presenting tissues. Clinically relevant HER2/HER3-targeting antibodies revert tumor sphere polarity, and impede collagen remodeling and adhesion to mouse peritoneum. This SorLA-integrin-HER2/HER3 axis could represent a MUC CRC-patient stratification approach and be relevant for other carcinomas with apical-out phenotypes.

LKB1 mutations in lung cancer promote an immunosuppressive tumor microenvironment, but the underlying mechanisms remain unknown. Using genetically engineered mouse models and human tumor samples, we demonstrate that LKB1 loss leads to high expression of the cytokine leukemia-inhibitory factor (LIF), which through a cancer cell-autonomous autocrine loop, orchestrates the infiltration of immunosuppressive SiglecFHi neutrophils and Arg1+ interstitial macrophages. Genetic deletion of Lifr, the receptor for LIF, on Lkb1-mutant lung tumors revealed that autocrine LIF signaling induces tumor plasticity and the emergence of a Sox17+ dedifferentiated inflammatory cell state. Antibody-mediated LIF neutralization selectively eliminates the Sox17+ tumor cell state, reduces immunosuppressive myeloid cells, and enhances antitumor T-cell responses. Our study uncovers a novel LKB1-LIF axis driving immune evasion and identifies LIF as a potential therapeutic target in LKB1-mutant lung cancer. This work highlights the interplay between tumor genetics, cellular plasticity, and immune regulation in lung cancer progression.

Despite the advancement in therapies, ovarian cancer treatment is challenging because of poor prognosis and high relapse associated with acquired resistance. Emerging targeted alpha particles, particularly actinium-225 (225Ac), for treating refractory cancers have opened avenues for improved therapeutic options. Here, we describe a successful example of folate receptor 1 (FOLR1)-targeted 225Ac alpha-particle therapy for treatment of ovarian cancer. Longitudinal positron emission tomography imaging demonstrated high tumor-specific uptake of αFOLR1 (anti-FOLR1 antibody) in SKOV3 xenografts. FOLR1-targeted 225Ac demonstrated high therapeutic efficacy, achieving marked tumor regression, 80% survival, and 40% complete tumor elimination. The therapy resulted in tumor-specific double-stranded DNA damage, and no obvious toxicity was observed in normal tissues. Estimated human dosimetry showed high absorbed dose for tumor and minimal absorbed dose for healthy tissues, establishing its safety. In totality, FOLR1-targeted 225Ac alpha-particle therapy is an efficacious and safe treatment with high feasibility for clinical translation to fight against ovarian cancer.