Project description:Activation of the cGAS/STING innate immunity pathway is essential and effective for anti-tumor immunotherapy. However, it remains largely elusive how tumor-intrinsic cGAS signaling is suppressed to facilitate tumorigenesis by escaping immune surveillance. Here, we report that the protein arginine methyltransferase, PRMT1, methylates cGAS at the conserved Arg133 residue, which prevents cGAS dimerization and suppresses the cGAS/STING signaling in cancer cells. Notably, genetic or pharmaceutical ablation of PRMT1 leads to activation of cGAS/STING-dependent DNA sensing signaling, and robustly elevates the transcription of type I and II interferon response genes. As such, PRMT1 inhibition elevates tumor-infiltrating lymphocytes in a cGAS-dependent manner, and promotes tumoral PD-L1 expression. Thus, combination therapy of PRMT1 inhibitor with anti-PD-1 antibody augments the anti-tumor therapeutic efficacy in vivo. Our study therefore defines the PRMT1/cGAS/PD-L1 regulatory axis as a critical factor in determining immune surveillance efficacy, which serves as a promising therapeutic target for boosting tumor immunity.
Project description:Microsatellite-stable colorectal cancer (MSS-CRC) is highly refractory to immunotherapy. Understanding tumor-intrinsic determinants of immunotherapy resistance is critical to improve MSS-CRC patient outcomes. Here, we demonstrate that high tumor expression of the core autophagy gene ATG16L1 is associated with poor clinical response to anti-PD-L1 therapy in KRAS-mutant tumors from IMblaze370 (NCT02788279), a large phase III clinical trial of atezolizumab (anti-PD-L1) in advanced metastatic MSS-CRC. Deletion of Atg16l1 in engineered murine colon cancer organoids inhibits tumor growth in primary (colon) and metastatic (liver and lung) niches in syngeneic female hosts, primarily due to increased sensitivity to IFN-γ-mediated immune pressure. ATG16L1 deficiency enhances programmed cell death of colon cancer organoids induced by IFN-γ and TNF, thus increasing their sensitivity to host immunity. In parallel, ATG16L1 deficiency reduces tumor stem-like populations in vivo independently of adaptive immune pressure. This work reveals autophagy as a clinically relevant mechanism of immune evasion and tumor fitness in MSS-CRC and provides a rationale for autophagy inhibition to boost immunotherapy responses in the clinic.
Project description:CD8+ T cell-mediated immune response plays an important role in inhibiting progression of hepatocellular carcinoma (HCC). For strategic immunotherapy, it is critical to understand why some of the tumor cells escape from this immune attack. In this study, we investigated how HCC cells alter endogenous anti-tumor immunity and their related signaling pathways. We found that HCC cells, both in vitro and in vivo, substantially secret and express amphiregulin (AR). AR in turn activates immunosuppressive function of intratumoral CD4+Foxp3+ regulatory T cells (Tregs), a major inhibitor of CD8+ T cells. Using either lentiviral siRNA, or AR neutralizing antibody, we blocked the expression and function of AR to test the specificity of AR mediated activation of Tregs, Biochemical and cell biology studies were followed and confirmed that blocking of AR inhibited Tregs activation. In addition, we found that AR can trigger the activation of rapamycin complex 1(mTORC1) signaling in Tregs. The mTORC1 inhibitor rapamycin treatment led to compromise Treg function and resulted in enhancing anti-tumor function of CD8+ T cells. Blocking AR/EGFR signaling in Tregs with Gefitinib also enhanced anti-tumor immunity and decreased tumor size in a mouse xenograft tumor model. Taken together, our study suggested a novel mechanism of functional interaction between HCC and Tregs for regulating anti-tumor function of CD8+ T cells.
Project description:Here we demonstrate that inactivation of the essential autophagy genes, Atg5, Atg14, or Atg16L1 results in tumour rejection. Despite a significant reduction in the total number of CD8+ tumour infiltrating lymphocytes (TILs), loss of Atg5 causes a profound shift toward IFNg and TNF producing effector memory cells. Consistent with this, adoptive transfer with Atg5-/- T cells promotes tumour control. Mechanistically, CD8+ T cells lacking autophagy exhibit enhanced glucose metabolism resulting in global changes in histone trimethylation and increased transcriptional activation of effector target genes. Restricting glucose is sufficient to suppress autophagy-dependent increases in effector function and reverse alterations in histone trimethylation. These findings identify autophagy as a cell-autonomous negative regulator of CD8+ T cell anti-tumour immunity with implications on T cell-based immunotherapy.
Project description:The vast majority of colorectal cancer (CRC) patients fail to respond to immune checkpoint inhibitors (ICI). Understanding tumor-intrinsic determinants of immunotherapy resistance is critical to improve CRC patient outcomes. Here, we demonstrate that transcript levels of the core autophagy gene ATG16L1 are prognostic of poor outcome and predictive of ICI resistance in late-stage CRC. Deletion of Atg16l1 in murine CRC organoids markedly inhibited tumor growth in primary and metastatic niches in syngeneic hosts. ATG16L1 deficiency rendered CRC organoids more responsive to interferon (IFN) signaling and enhanced programmed cell death while decreasing tumor stem-like populations. IFN hypersensitivity consequently promoted cytotoxic anti-tumor immunity in vivo. In IMblaze370, a large phase III clinical trial of anti-PD-L1 in advanced metastatic CRC, low ATG16L1 levels identified patients with increased lymphocyte infiltration and improved outcome in a KRAS mutant setting. This work reveals autophagy as a clinically relevant immunosuppressive mechanism in CRC and provides a rationale for autophagy inhibition to boost immunotherapy responses in the clinic.
Project description:PRMT1 is known as a regulator of immune function by directly interacting with interferon receptors, methylating STAT1, and promoting B cell and macrophage differentiation by methylating CDK4 or B cell antigen receptor However, the function of PRMT1 as a therapeutic target of cancer remains largely elusive, particularly for its role in cancer immunosurveillance. Here, we performed bulk RNA-seq for CT26, a mouse tumor cell line, after either knocking down of endogeneous Prmt1 or blocking PRMT1 by two specific inhibitors, namely MS023 and GSK3368715.
Project description:BackgroundWomen have a lower risk of hepatocellular carcinoma (HCC) than men, and the decreased possibility of HCC in women is thought to depend on estrogen levels. As a soybean-isoflavone product, genistein has estrogenic activity in various reproductive tissues, because it mimics 17β-estradiol and binds the estrogen receptor. Though genistein is a known liver cancer suppressor, its effects have not been studies in long-term experiment, where genistein is fed to a female animal model of HCC.MethodsMice were treated with diethylnitrosamine (DEN) to induce HCC at 2 weeks of age and fed with supplemental genistein for 5 months, from 40 to 62 weeks of age.ResultsThe dietary intake of genistein decreased the incidence of HCC and suppressed HCC development. Genistein induced phospho-AMPK in total liver extracts, Hep3B cells, and Raw 264.7 cells, and phospho-AMPK promoted apoptosis in liver and Hep3B cells. Moreover, phospho-AMPK down-regulated pro-inflammatory responses and ameliorated liver damage. A suppressed pro-inflammatory response with increased mitochondrial respiration was concomitantly observed after genistein treatment.ConclusionsGenistein-mediated AMPK activation increases hepatocyte apoptosis through energy-dependent caspase pathways, suppresses the inflammatory response in resident liver macrophages by increased cellular respiration, and consequently inhibits the initiation and progression of HCC.
Project description:Hepatocellular carcinoma (HCC) is a leading cause of cancer mortality, necessitating innovative therapeutic approaches. This study demonstrates that the compound CC-885 exerts potent anti-tumor effects in HCC both in vitro and in vivo. CC-885 significantly inhibited proliferation, migration, and invasion of HCC cells. In vivo, CC-885 markedly reduced tumor growth and angiogenesis in chick embryo and mouse xenograft models. Mechanistically, CC-885 selectively reduced GOLM1 protein levels via ubiquitin-mediated proteasomal degradation, without affecting its mRNA levels. GOLM1 knockdown mimicked the anti-proliferative effects of CC-885, while overexpression of GOLM1 conferred resistance to CC-885-induced apoptosis and growth inhibition. CC-885 facilitated the interaction between GOLM1 and the E3 ubiquitin ligase CRBN, promoting GOLM1 ubiquitination and degradation. Transcriptomic analyses revealed that CC-885 and GOLM1 knockdown modulated key pathways involved in apoptosis, NF-κB signaling, and cell proliferation. These findings highlight CC-885 as a promising therapeutic agent for HCC, primarily by facilitating the CRBN-dependent degradation of GOLM1, underscoring its potential for clinical application.