Cancer cell intrinsic SSBP4 enables tumor immune evasion by promoting cholesterol biosynthesis [RNA-Seq]
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE328719 | GEO | 2026/04/30
REPOSITORIES: GEO
Similar Datasets
Project description:The immunosuppressive tumor microenvironment (TME) contributes to resistance against checkpoint inhibitors. However, the precise factors that shape the immune contexture of the TME remain elusive. Here, we report that Single-Stranded DNA Binding Protein 4 (SSBP4), a previously uncharacterized protein, suppresses intratumoral T-cell activation by promoting excessive cholesteryl ester production in tumor cells. Overexpression of SSBP4 in tumor cells decreased T-cell infiltration and accelerated tumor growth in murine syngeneic tumor models. Conversely, genetic ablation of SSBP4 in tumor cells enhanced T-cell infiltration and inhibited tumor growth in a CD8+ T cell–-dependent manner. Mechanistically, SSBP4 upregulated cholesterol synthesis genes, leading to increased production of cholesterol and cholesteryl esters in tumor cells, which directly suppressed CD8+ T-cell activation and function. Furthermore, SSBP4 abrogation significantly improved the efficacy of anti-PD-1 treatment. Thus, in this study, we have identified SSBP4 as a cancer cell–intrinsic regulator of cholesterol metabolism that contributes to tumor immune evasion.
2026-04-30 | GSE328971 | GEO
Project description:The immunosuppressive tumor microenvironment (TME) contributes to resistance against checkpoint inhibitors. However, the precise factors that shape the immune contexture of the TME remain elusive. Here, we report that Single-Stranded DNA Binding Protein 4 (SSBP4), a previously uncharacterized protein, suppresses intratumoral T-cell activation by promoting excessive cholesteryl ester production in tumor cells. Overexpression of SSBP4 in tumor cells decreased T-cell infiltration and accelerated tumor growth in murine syngeneic tumor models. Conversely, genetic ablation of SSBP4 in tumor cells enhanced T-cell infiltration and inhibited tumor growth in a CD8+ T cell–-dependent manner. Mechanistically, SSBP4 upregulated cholesterol synthesis genes, leading to increased production of cholesterol and cholesteryl esters in tumor cells, which directly suppressed CD8+ T-cell activation and function. Furthermore, SSBP4 abrogation significantly improved the efficacy of anti-PD-1 treatment. Thus, in this study, we have identified SSBP4 as a cancer cell–intrinsic regulator of cholesterol metabolism that contributes to tumor immune evasion.
2026-04-30 | GSE328718 | GEO
Project description:The immunosuppressive tumor microenvironment (TME) contributes to resistance against checkpoint inhibitors. However, the precise factors that shape the immune contexture of the TME remain elusive. Here, we report that Single-Stranded DNA Binding Protein 4 (SSBP4), a previously uncharacterized protein, suppresses intratumoral T-cell activation by promoting excessive cholesteryl ester production in tumor cells. Overexpression of SSBP4 in tumor cells decreased T-cell infiltration and accelerated tumor growth in murine syngeneic tumor models. Conversely, genetic ablation of SSBP4 in tumor cells enhanced T-cell infiltration and inhibited tumor growth in a CD8+ T cell–-dependent manner. Mechanistically, SSBP4 upregulated cholesterol synthesis genes, leading to increased production of cholesterol and cholesteryl esters in tumor cells, which directly suppressed CD8+ T-cell activation and function. Furthermore, SSBP4 abrogation significantly improved the efficacy of anti-PD-1 treatment. Thus, in this study, we have identified SSBP4 as a cancer cell–intrinsic regulator of cholesterol metabolism that contributes to tumor immune evasion. Immune-related gene expression was quantified using the Nanostring Mouse PanCancer Immune Profiling panel. Total RNA was isolated from the C57BL/6 SSBP4-wildtype or knockout B16F10 tumors on Day 15 post tumor inoculation. RNA was hybridized, scanned on a Nanostring Digital Analyzer, and raw RCC files were generated. Raw count data were processed and normalized in nSolver or ROSALIND software for downstream immune transcriptome profiling.
2026-04-30 | GSE329266 | GEO
Project description:The immunosuppressive tumor microenvironment (TME) contributes to resistance against checkpoint inhibitors. However, the precise factors that shape the immune contexture of the TME remain elusive. Here, we report that Single-Stranded DNA Binding Protein 4 (SSBP4), a previously uncharacterized protein, suppresses intratumoral T-cell activation by promoting excessive cholesteryl ester production in tumor cells. Overexpression of SSBP4 in tumor cells decreased T-cell infiltration and accelerated tumor growth in murine syngeneic tumor models. Conversely, genetic ablation of SSBP4 in tumor cells enhanced T-cell infiltration and inhibited tumor growth in a CD8+ T cell–-dependent manner. Mechanistically, SSBP4 upregulated cholesterol synthesis genes, leading to increased production of cholesterol and cholesteryl esters in tumor cells, which directly suppressed CD8+ T-cell activation and function. Furthermore, SSBP4 abrogation significantly improved the efficacy of anti-PD-1 treatment. Thus, in this study, we have identified SSBP4 as a cancer cell–intrinsic regulator of cholesterol metabolism that contributes to tumor immune evasion. Immune-related gene expression was quantified using the Nanostring nCounter Myeloid Innate Immunity Panel. Total RNA was isolated from splenic CD8 T cells of C57BL/6 mice, where were cultured with conditioned media from SSBP4-wildtype or knockout B16F10 tumor cells. RNA was extracted from CD8 T cells, hybridized, scanned on a Nanostring Digital Analyzer, and raw RCC files were generated. Raw count data were processed and normalized in nSolver software for downstream immune transcriptome profiling.
2026-04-30 | GSE329267 | GEO
Project description:PD-1 blockade therapy exerts antitumor effects by restoring the infiltration of tumor antigen-specific CD8+ T cells. While neoantigens arising from gene alterations in cancer cells comprise critical tumor antigens in antitumor immunity, a subset of non-small-cell lung cancers (NSCLCs) harboring substantial tumor mutation burden (TMB) lack CD8+ T cells in the tumor microenvironment (TME), resulting in resistance to PD-1 blockade therapy. This resistance is an urgent issue, so the mechanism(s) mediating impaired antitumor immunity in highly mutated NSCLCs need to be explored. Here, we show that activation of the WNT/b-catenin signaling pathway contributes to the development of a noninflamed TME in tumors with high TMB. NSCLCs that lack immune cell infiltration into the TME despite high TMB preferentially upregulate the WNT/b-catenin pathway. Immunological assays revealed that those patients harbored neoantigen-specific CD8+ T cells in the peripheral blood but not in the TME, suggesting impaired T cell infiltration into the TME due to the activation of WNT/b-catenin signaling. In our animal model, the accumulation of gene mutations in cancer cells increased CD8+ T cell infiltration into the TME, slowing tumor growth. However, further accumulation of gene mutations blunted antitumor immunity by excluding CD8+ T cells from tumors in a WNT/b-catenin signaling-dependent manner. Combined treatment with PD-1 blockade and WNT/b-catenin signaling inhibitors induced far stronger antitumor immunity than either treatment alone. We propose a mechanism-oriented combination therapy concept in the cancer immunotherapy field, i.e., the combination of immune checkpoint inhibitors with drugs that target specific molecules in cancer cell-intrinsic oncogenic signaling pathways involved in immune escape.
2021-09-17 | GSE181820 | GEO
Project description:Non-alcoholic fatty liver disease (NAFLD) is an emerging risk factor of hepatocellular carcinoma (HCC). However, the mechanism and target therapy on NAFLD-HCC are still unclear. Here, we identify that the N6-methyladenosine (m6A) methyltransferase METTL3 promotes NAFLD-HCC. Hepatocyte-specific Mettl3 knockin exacerbated NAFLD-HCC formation while Mettl3 knockout exerted an opposite effect in mice. Single-cell RNA-seq revealed that METTL3 suppressed antitumor immune response by reducing infiltration of Gzmb+ and IFN-γ+ CD8+ T-cell, thereby facilitating immune escape. Mechanistically, METTL3 mediates SCAP mRNA m6A to promote its translation, leading to the activation of cholesterol biosynthesis. This enhanced secretion of cholesterol and cholesteryl esters, lipotoxins that impaired CD8+ T cell function in tumor microenvironment. Targeting of METTL3 by sgRNA, nanoparticle-siRNA, or pharmacological inhibitor (STM2457) in combination with anti-PD1 synergized to reinvigorate cytotoxic CD8+ T cells and mediate tumor regression. Together, METTL3 is a therapeutic target in NAFLD-HCC, especially in conjunction with immune checkpoint blockade (ICB) therapy.
2023-08-23 | GSE233807 | GEO
Project description:Non-alcoholic fatty liver disease (NAFLD) is an emerging risk factor of hepatocellular carcinoma (HCC). However, the mechanism and target therapy on NAFLD-HCC are still unclear. Here, we identify that the N6-methyladenosine (m6A) methyltransferase METTL3 promotes NAFLD-HCC. Hepatocyte-specific Mettl3 knockin exacerbated NAFLD-HCC formation while Mettl3 knockout exerted an opposite effect in mice. Single-cell RNA-seq revealed that METTL3 suppressed antitumor immune response by reducing infiltration of Gzmb+ and IFN-γ+ CD8+ T-cell, thereby facilitating immune escape. Mechanistically, METTL3 mediates SCAP mRNA m6A to promote its translation, leading to the activation of cholesterol biosynthesis. This enhanced secretion of cholesterol and cholesteryl esters, lipotoxins that impaired CD8+ T cell function in tumor microenvironment. Targeting of METTL3 by sgRNA, nanoparticle-siRNA, or pharmacological inhibitor (STM2457) in combination with anti-PD1 synergized to reinvigorate cytotoxic CD8+ T cells and mediate tumor regression. Together, METTL3 is a therapeutic target in NAFLD-HCC, especially in conjunction with immune checkpoint blockade (ICB) therapy.
2023-08-23 | GSE233806 | GEO
Project description:Cervical cancer (CC) is one of the most common malignancy in women worldwide. It is characterized by a natural continuous phenomenon, that is, it is in the initial stage of HPV infection, progresses to intraepithelial neoplasia, and then develops into invasion and metastasis. Determining the complexity of tumor microenvironment (TME) can deepen our understanding of lesion progression and provide novel therapeutic strategies for CC. We performed the single-cell RNA sequencing on the normal cervix, intraepithelial neoplasia, primary tumor and metastatic lymph node tissues to describe the composition, lineage, and functional status of immune cells and mesenchymal cells at different stages of CC progression. A total of 59913 single cells were obtained and divided into 9 cellular clusters, including immune cells (T/NK cells, macrophages, B cells, plasma cells, mast cells and neutrophils) and mesenchymal cells (endothelial cells, smooth muscle cells and fibroblasts). Our results showed that there were distinct cell subpopulations in different stages of CC. High-stage intraepithelial neoplasia (HSIL) tissue exhibited a low, recently activated TME, and it was characterized by high infiltration of tissue-resident CD8 T cell, effector NK cells, Treg, DC1, pDC, and M1-like macrophages. Tumor tissue displayed high enrichment of exhausted CD8 T cells, resident NK cells and M2-like macrophages, suggesting immunosuppressive TME. Metastatic lymph node consisted of naive T cell, central memory T cell, circling NK cells, cytotoxic CD8+ T cells and effector memory CD8 T cells, suggesting an early activated phase of immune response. This study is the first to delineate the transcriptome profile of immune cells during CC progression using single-cell RNA sequencing. Our results indicated that HSIL exhibited a low, recently activated TME, tumor displayed immunosuppressive statue, and metastatic lymph node showed early activated phase of immune response. Our study enhanced the understanding of dynamic change of TME during CC progression and has implications for the development of novel treatments to inhibit the initiation and progression of CC.
2022-10-08 | E-MTAB-12305 | biostudies-arrayexpress
Project description:Axicabtagene ciloleucel (axi-cel), an anti-CD19 chimeric antigen receptor (CAR) T-cell therapy approved for treatment of relapsed/refractory large B-cell lymphoma (LBCL), has comparable efficacy across conventional LBCL markers. We analysed whether pre- and posttreatment tumour immune contexture determines clinical outcomes for axi cel–treated patients in the ZUMA-1 pivotal study. Longitudinal evaluation of the tumour microenvironment (TME) uncovered dynamic patterns that occurred rapidly after axi-cel (within 2 weeks) in responders—pronounced enhancement of T- and myeloid cell signatures and diminution of B cell signature. Clinical response and overall survival associated with high CD8+ T-cell density (Immunoscore) and immune gene expression (Immunosign21) in TME pretreatment, which was paralleled by blood CAR T-cell levels posttreatment. High density of regulatory T cells in TME pretreatment associated with reduced axi-cel–related neurologic toxicity. At relapse, the TME evolved toward an immune-detrimental contexture with decreased T-cell–related and increased counterregulatory immune signatures and B cell lineage antigens. A TME rich in T-cell attractive chemokines (CCL5, CCL22), gamma-chain receptor cytokines (IL-15, IL-7, IL-21), and interferon regulated molecules associated with T-cell infiltration and markers of activity, a result validated in 2 independent datasets totalling ≈300 LBCL samples. These findings advance mechanistic understanding of CAR T-cell therapy and foster biomarker development and treatment optimizations.
2022-09-23 | GSE197977 | GEO
Project description:Regulatory T cells (Tregs) are a key mediator of resistance to cancer immunotherapy, including anti-PD-(L)1 immune checkpoint blockade (ICB). Tregs perpetually infiltrate tumors and hamper effective anti-tumor immunity. The mechanisms driving Treg infiltration into the tumor microenvironment (TME) and the consequence on CD8+ T cell exhaustion remains elusive. Herein, we report that heat shock protein gp96 (GRP94) is indispensable for Treg infiltration into the tumor, primarily through gp96’s roles in chaperoning integrins. Among various gp96-dependent integrins, we found that only LFA-1 (αL integrin) but not integrin αV, CD103 (αE) or β7 was required for Treg homing into the tumors. Loss of Treg infiltration into the TME by genetically deleting gp96/LFA-1 potently induces rejection of multiple ICB-resistant murine cancer models in a CD8+ T cell dependent manner without loss of self-tolerance. Moreover, gp96 deletion impeded Treg activation primarily by suppressing IL-2/phosphorylated STAT5 (pSTAT5) signaling pathway, which also contributes to tumor regression. Notably, by a mechanism in part through competing for IL-2 in the TME, intra-tumoral Tregs prevent activation of CD8+ tumor-infiltrating lymphocytes (TILs), drive TOX induction and induce bona fide CD8+ T cell exhaustion. By contrast, Treg ablation leads to a striking CD8+ T cell activation without TOX induction, demonstrating clear uncoupling of the two processes. Our study reveals that the gp96/LFA-1 axis plays a fundamental role in Treg biology and intratumoral CD8+ T cell exhaustion. We suggest that, Treg-specific targeting of gp96/LFA-1 represents a novel strategy for cancer immunotherapy without inflicting autoinflammatory conditions.
2024-05-05 | GSE266362 | GEO