ShCTRL and shOrai1, IFN-γ 6 hr
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo Sapiens (human)
SUBMITTER: Masanari Umemura
PROVIDER: PXD066968 | JPOST Repository | Wed Aug 05 00:00:00 BST 2026
REPOSITORIES: jPOST
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Project description:Tumor cells frequently develop immune resistance through interferon-γ (IFN-γ)–induced PD-L1 expression, acquisition of cancer stem cell (CSC)–like features, and adaptation to hypoxia within the tumor microenvironment (TME). Although IFN-γ activates both STAT1 and STAT3, how these pathways interact to regulate immune evasion under hypoxia remains unclear. Using the MC38 murine colorectal cancer model and T cell–tumor spheroid co-culture assays, we examined how IFN-γ signaling through STAT1 and STAT3 regulates PD-L1 expression, CSC plasticity, and cytotoxic T cell function under normoxic and hypoxic conditions. Pharmacologic inhibitors and siRNA-mediated knockdown were used to dissect pathway function, and Niclosamide, an FDA-approved anthelmintic, was evaluated as a dual STAT1/STAT3 inhibitor. We found that IFN-γ primarily induced PD-L1 expression through STAT1 activation, whereas CSC plasticity was associated with STAT3 signaling. STAT1 and STAT3 displayed reciprocal regulation—blocking one enhanced activation of the other. Niclosamide effectively inhibited phosphorylation of both STAT1 and STAT3, resulting in suppressed PD-L1 upregulation and reduced CSC enrichment. In addition, it also partially inhibited hypoxia-induced HIF-1α expression. In co-culture assays, Niclosamide enhanced T cell infiltration and reduced exhaustion under hypoxic conditions, resulting in improved T cell killing. Our findings identified Niclosamide as a potent dual STAT1/3 inhibitor capable of reversing IFN-γ and hypoxia-driven immune evasion. Repurposing Niclosamide may represent a promising strategy to enhance the efficacy of immune checkpoint blockade in solid tumors.
2026-04-08 | GSE320497 | GEO
Project description:PD-L1 functions as a co-inhibitory checkpoint ligand constraining anti-tumor immunity by binding to PD-1 on immune cells. Although antibody blockade therapy displays clear therapeutic responses, it is not effective in all cancer patients, indicating modulation by other factors. We applied cell surface proximity biotinylation combined with mass spectrometry in melanoma cells to identify novel proteins regulating PD-L1 function. Our findings reveal that membrane organizing protein Tetraspanin-4 (TSPAN4) interacts with PD-L1, where both proteins colocalize on migrasomes and retraction fibers. We demonstrate that TSPAN4 negatively affects PD-L1 protein levels and inhibits PD-L1 lateral mobility on the plasma membrane. TSPAN4 knockdown results in a reduced PD-L1 degradation rate, and enhanced PD-L1 interaction with CMTM6 as the molecular mechanism. Consequently, increased PD-L1 levels in TSPAN4 knockdown melanoma cells leads to enhanced PD-1 binding, and more efficient immune checkpoint blockade through inhibition of T cell responses. This study identifies TSPAN4 as a negative regulator of PD-L1 at the cell surface of melanoma cells, suggesting that TSPAN4 may represent a novel target for improving immune checkpoint therapy in cancer patients.
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Project description:PD-L1 suppresses host immunity and promotes tumor growth. We investigated how IFN-? regulates PD-L1 in the ovarian cancer microenvironment. In clinical samples, the number of stromal CTLs in peritoneally disseminated tumors was correlated with PD-L1 expression on the tumor cells, and the lymphocyte number was significantly related to the IFN-? signature score. In mouse models, PD-L1 was induced in peritoneal disseminated tumors, where lymphocytes were prominent, but not in subcutaneous tumors. Depleting IFNGR1 resulted in lower PD-L1 expression and longer survival in peritoneal dissemination model. Injection of IFN-? into subcutaneous tumors increased PD-L1 expression and tumor size, and PD-L1 depletion abrogated tumor growth. These data suggest that IFN-? works as a tumor progressor through PD-L1 induction. The source of IFN-? in ovarian cancer microenvironment and its biological effect to the tumor cells is unclear. The immortalized human ovarian surface epithelial cell line, HOSE-E7/hTERT (HOSE) was treated with IFN-? and expression microarray analysis was performed, and probes showing significantly higher values in IFN-?-added group were termed “IFN-? signature genes (295 probes)”. We then applied this signature to our ovarian cancer microarray data, which included 75 ovarian cancer clinical samples, by means of ss-GSEA. IFN-? signature score was strongly correlated to the number of infiltrating CD4-positive or CD8-positive lymphocytes in the tumors. These data suggest that the IFN-? in the ovarian cancer microenvironment is derived from lymphocytes, and an IFN-?-rich microenvironment is strongly correlated to a lymphocyte-rich microenvironment. Genome-wide transcriptional changes in human ovarian cancer tissue were observed in different tumor immunological microenvironment.
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Project description:MAPK inhibitor (MAPKi) therapy in melanoma leads to accumulation of tumor-surface PD-L1/2, which may evade antitumor immunity and accelerate acquired resistance. Here, we discover that the E3 ligase ITCH binds, ubiquitinates, and down-regulates tumor-surface PD-L1/L2 in MAPKi-treated human melanoma cells, thereby modulating activation of co-cultured T cells. During MAPKi therapy in vivo, tumor cell-intrinsic ITCH knockdown in murine melanoma induced tumor-surface PD-L1, reduced intratumoral cytolytic CD8+ T cells, and accelerated acquired resistance only in immune-proficient mice. Conversely, tumor cell-intrinsic ITCH over-expression reduced MAPKi-elicited PD-L1 accumulation, augmented cytolytic CD8+ T-cell infiltration, and suppressed acquired resistance in BrafMUT, NrasMUT, and Nf1MUT murine melanoma and KrasMUT pancreatic cancer models. CD8+ T-cell depletion and tumor cell-intrinsic PD-L1 over-expression nullified the ability of ITCH over-expression to suppress MAPKi-resistance, supporting in vivo the ITCH–PD-L1–T-cell regulatory axis demonstrated in human cancer cell lines. Moreover, we identified a small-molecular ITCH activator which suppressed acquired MAPKi-resistance in vivo. Thus, MAPKi-elicited tumor-surface PD-L1 accelerates acquired-resistance, and degrading PD-L1 by activating ITCH may be a combinatorial approach to promote antitumor T-cell immunity and durable responses.
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Project description:Primary outcome(s): 1. Overall Survival
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Timepoint: 1. Overall Survival
2. Evaluation of objective response through Immune related Response Criteria (irRC): measure of PD; PR and SD.
3. Immune response as assessed through Treg population and serum IFN-γ levels
4. Monitor treatment emergent adverse events.
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Project description:Targeting the PD-1/PD-L1 axis has transformed the field of immune-oncology. While conventional wisdom initially postulated that PD-L1 serves as the inert ligand for PD-1, an emerging body of literature suggests that PD-L1 has cell‑intrinsic functions in immune and cancer cells. In line with these studies, here we show that PD-L1 potently inhibits the type I interferon pathway in cancer cells. Hampered type I interferon responses in PD-L1-expressing cells resulted in enhanced infection with oncolytic viruses in cancer cells in vitro and in vivo. PD-L1 expression marks tumor explants from cancer patients that are best infected by oncolytic viruses. Agonistic antibodies targeting PD-L1 further reduced type I IFN responses and enhanced oncolytic virus infection. Mechanistically, PD-L1 suppressed type I interferon by promoting Warburg metabolism, characterized by enhanced glucose uptake and glycolysis rate. Lactate generated from glycolysis was the key metabolite responsible for inhibiting type I interferon responses and enhancing oncolytic virus infection in PD‑L1‑expressing cells. In addition to adding mechanistic insight into PD-L1 intrinsic function and showing that PD-L1 has a broader impact on immunity and cancer biology besides acting as a ligand for PD-1, our results will also help guide the numerous efforts currently ongoing to combine PD-L1 antibodies with oncolytic virotherapy in clinical trials.
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