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Synthetic lethal CRISPR screen identifies a cancer cell-intrinsic role of PD-L1 in regulation of vulnerability to ferroptosis [CRISPR screening]

ABSTRACT: Despite the remarkable success of programmed death 1/PD-L1 inhibition in tumor therapy, only a minority of patients benefits from it. Previous studies suggest the anti-PD-1 treatment failure may attribute to the intrinsic functions of PD-L1 in cancer cells. Here, we established a genome-wide CRISPR synthetic lethality screen to systematic explore the PD-L1 intrinsic function in head and neck squamous cell carcinoma (HNSCC) cells. Ferroptosis related genes were identified to be essential for PD-L1 deficient cell viability. Genetic and pharmacological induction of ferroptosis accelerated cell death in PD-L1 knockout cells. PD-L1 knockout cells were also highly susceptible to immunogenic ferroptosis in vitro and in vivo. Mechanistically, nuclear PD-L1 transcriptionally activated SOD2 expression to maintain redox homeostasis. Importantly, the lower ROS and ferroptosis were observed in HNSCC patients with the higher expression of PD-L1. In summary, our study illustrates that PD-L1 confers ferroptosis resistance by activating SOD2-meidated redox homeostasis in HNSCC cells, indicating an enhanced therapeutic effect can be achieved by targeting the intrinsic PD-L1 function during immunotherapy.

ORGANISM(S): Homo sapiens

PROVIDER: GSE268533 | GEO | 2024/07/08

REPOSITORIES: GEO

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Synthetic lethal CRISPR screen identifies a cancer cell-intrinsic role of PD-L1 in regulation of vulnerability to ferroptosis [CUT&Tag]

Project description:Despite the remarkable success of programmed death 1/PD-L1 inhibition in tumor therapy, only a minority of patients benefits from it. Previous studies suggest the anti-PD-1 treatment failure may attribute to the intrinsic functions of PD-L1 in cancer cells. Here, we established a genome-wide CRISPR synthetic lethality screen to systematic explore the PD-L1 intrinsic function in head and neck squamous cell carcinoma (HNSCC) cells. Ferroptosis related genes were identified to be essential for PD-L1 deficient cell viability. Genetic and pharmacological induction of ferroptosis accelerated cell death in PD-L1 knockout cells. PD-L1 knockout cells were also highly susceptible to immunogenic ferroptosis in vitro and in vivo. Mechanistically, nuclear PD-L1 transcriptionally activated SOD2 expression to maintain redox homeostasis. Importantly, the lower ROS and ferroptosis were observed in HNSCC patients with the higher expression of PD-L1. In summary, our study illustrates that PD-L1 confers ferroptosis resistance by activating SOD2-meidated redox homeostasis in HNSCC cells, indicating an enhanced therapeutic effect can be achieved by targeting the intrinsic PD-L1 function during immunotherapy.

2024-07-08 | GSE268534 | GEO

Immune checkpoint inhibitor monotherapy is sufficient to promote microenvironmental normalization via Type I interferon pathway in PD-L1+ expressing head and neck cancer

Project description:Immune checkpoint blockers (ICBs) targeting programmed death 1(PD-1) are considered effective first-line therapy against PD-1 ligand (PD-L1)-expressing head and neck squamous cell carcinoma (HNSCC). However, associated changes in tumor microenvironment (TME) and mechanisms remain elusive. Oral tumors in C57/BL6 mice were induced by administering 7,12-dimethylbenzanthracene into the buccal mucosa. Single-cell suspension was isolated from tumor tissue; proliferating cells were injected subcutaneously into the left flank of mice to establish Ajou Oral Cancer (AOC) cell lines. Subsequently, a syngeneic PD-L1-expressing HNSCC xenograft model was developed by injecting AOC cells into the buccal or tongue area. The model recapitulated human HNSCC molecular features and showed reliable in vivo tumorigenicity with significant PD-L1 expression. ICB monotherapy induced global changes in TME, including vascular normalization. Furthermore, the anti-tumor effect of ICB monotherapy was superior to those of other therapeutic agents, including cisplatin and anti-vascular endothelial growth factor receptor 2 inhibitors. The ICB-induced anti-tumorigenicity and TME normalization were alleviated by blocking the Type I interferon pathway.In summary, ICB monotherapy is sufficient to induce TME normalization in the syngeneic model; the Type-I interferon pathway is indispensable in realizing ICB effects. Furthermore, these results explain the underlying mechanism of the efficacy of ICB monotherapy against HNSCC expressing PD-L1 in the KEYNOTE-048 trial. This model can assist future research on HNSCC immunotherapy.

2023-12-01 | GSE248271 | GEO

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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.

2023-06-28 | GSE210884 | GEO

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2022-05-31 | GSE199733 | GEO

Activation and acetylation of tumor-intrinsic PD-L1 via HBXIP accelerates breast cancer growth

Project description:Programmed death ligand-1 (PD-L1) is a well-known transmembrane protein, which antibodies present effective clinical therapy in multiple human cancers. However, the function of tumor cell-intrinsic PD-L1 and its related mechanism in breast cancer remains incompletely studied. Programmed death ligand 1 (PD-L1) on the membrane of tumor cells strengthens tumor immune escape. Tumor cell-intrinsic PD-L1 is also involved in tumorigenesis and development, but the mechanism in regulating PD-L1 expression remains incompletely studied. Here, we report a novel mechanism for PD-L1 that can be induced by hepatitis B X-interacting protein (HBXIP), an oncogenic transcriptional coactivator, promoting breast cancer growth. Overexpression of PD-L1 increases breast cancer proliferation in vitro and in vivo. Transcriptomic analysis also reveals that PD-L1 plays a critical role in cancer development. Furthermore, we find that the expression of PD-L1 is positively associated with HBXIP in breast cancer clinical tissues as well as in cell lines, PD-L1 and HBXIP expression have higher levels in tumor. Mechanistically, HBXIP predominantly stimulates the promoter activity of PD-L1 through coactivating transcription factor ETS2. Especially, HBXIP induced PD-L1 acetylation with the acetyltransferase p300 at lysine 270 (K270), enhancing PD-L1 protein stability. Functionally, depletion of HBXIP markedly attenuates PD-L1-induced breast tumor growth in vitro and in vivo. Moreover, aspirin decreased breast cancer growth via targeting PD-L1 and HBXIP. Taken together, our results extend a new mechanism of PD-L1 functions, expound non-immune effects of PD-L1 and imply broader uses for PD-L1 as a target in breast cancer therapy.

2022-02-02 | GSE158696 | GEO

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Project description:Anti-programmed cell death 1 (PD-1) therapy shows definite but modest activity in patients with advanced/metastatic HNSCC. Preliminary evidence suggests that SN-38, an activated form of irinotecan that activates the transcription factor FoxO3a, may suppress the expression of PD-L1 in breast and ovarian tumor models. Here, we explore the efficacy of SN-38 in combination with anti-PD1 for HNSCC treatment. In vitro, SN-38 enhances FoxO3a expression and reduces the expression of PD-L1 dose-dependently in HNSCC cells. Low dose SN-38 increases interferon- excretion by natural killer (NK) cells and promotes NK cell-mediated cytotoxicity of tumor cells. In vivo studies reveal that, at non-cytotoxic drug concentrations, SN-38 significantly enhances anti-PD-1 activity in suppressing murine tumor growth. An increased infiltration of CD8+ T cells and NK cells was found in the post-treatment tumors. RNA-seq analysis confirms that SN-38 promotes the enrichment of immune cells and biological function genes related to the immune response became abundant in SN-38 and anti-PD1 treated tumors. Thus, SN-38 is a potentially beneficial adjunct to checkpoint inhibitor therapy in HNSCC. Further studies to explore its mechanism of action and possible application are mandatory.

2023-01-11 | GSE222450 | GEO

A novel IFNα-induced long noncoding RNA, lncMX1-215, negatively regulates immunosuppression by interrupting H3K27 acetylation in head and neck squamous cell carcinoma

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2021-04-08 | GSE171650 | GEO

SOD2 promotes gastric tumorigenesis mediated by Helicobacter pylori and enhances resistance to 5-fluorouracil in gastric cancer

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