Oncogene最新文献

The USP37 gene encodes a deubiquitylase (DUB), which catalyzes the proteolytic removal of ubiquitin moieties from proteins to modulate their stability, cellular localization or activity. Its expression is downregulated in a subgroup of medulloblastomas driven by constitutive activation of sonic hedgehog (SHH) signaling. Patients with SHH-driven medulloblastomas with elevated expression of the RE1 silencing transcription factor (REST) and reduced expression of USP37 have poor outcomes. In previous studies, we showed sustained proliferation of SHH-medulloblastoma cells due to blockade of terminal cell cycle exit and neuronal differentiation stemming from a failure in USP37-dependent stabilization of its target, the cyclin-dependent kinase inhibitor (CDKI)-p27. This finding suggested a tumor suppressive function for USP37. Interestingly, the current study also uncovered Raptor, a component of the mTORC1 complex, as a novel target of USP37. Under conditions of low-USP37 expression, reduced Raptor stability and mTORC1 activity caused a decline in phosphorylation of 4E-binding protein 1 (4EBP1) and increased its interaction with eukaryotic elongation factor 4E (eIF4E), which is known to inhibit CAP-dependent translation initiation. Surprisingly, a subset of patients with SHH-driven medulloblastomas with elevated expression of USP37 and the Glioma-associated Oncogene 1 (GLI1), also exhibited poor outcomes. Using genetic and biochemical analyses, we showed that USP37-mediated stabilization of GLI1, a terminal effector of SHH signaling, increases pathway activity and upregulates expression of its target oncogene product, CCND1, to drive cell proliferation. These data indicate that USP37 elevation in SHH-driven medulloblastomas has the potential to promote non-canonical activation of SHH signaling. Overall, our findings suggest that USP37 may have context-specific oncogenic and tumor suppressive roles in medulloblastoma cells.

Numerous ubiquitination-related proteases (URPs) have been identified as facilitators of disease progression through the disruption of ubiquitination homeostasis in substrate proteins. Notably, some URPs have exhibited non-classical biological functions. In this study, we experimentally elucidate the role of the E3 ubiquitin ligase IRF2BPL as transcriptional activator that promotes malignant phenotypes in esophageal squamous cell carcinoma (ESCC) and inhibits the infiltration of various immune cells within the tumor microenvironment. Specifically, we found that IRF2BPL is highly expressed in ESCC cells and promotes IGFBP2 transcription, thereby facilitating ESCC development both in vivo and in vitro. Moreover, the chemical drug ONC201 was shown to effectively impede ESCC progression induced by the hyperactive IRF2BPL-IGFBP2 axis in tumor cells. Collectively, our findings verified that the IRF2BPL-IGFBP2 axis plays a critical role in enhancing ESCC progression by increasing the malignancy of ESCC cells and fostering an immune-deficient tumor microenvironment. Targeting the IRF2BPL-IGFBP2 axis may represent a promising therapeutic strategy for ESCC.

Ovarian cancer (OC) remains a lethal malignancy with limited treatment options owing to antigen heterogeneity and an immunosuppressive tumor microenvironment (TME). Here, we designed a unique chimeric Antigen Receptor T-Cell (CAR-T) construct (B4M3) that integrates an anti-MSLN scFv linked to the CD3ζ activation domain and an anti-B7H3 scFv linked to the 4-1BB co-stimulatory domain. In vitro, B4M3 CAR-T cells exhibited robust cytotoxicity against OC cell lines with enhanced degranulation (CD107a) and efficient tumor cell killing, even at low effector-to-target ratios. In vivo, B4M3 CAR-T cells significantly inhibited tumor growth and prolonged survival and demonstrated superior tumor infiltration and persistence in OC xenograft models. Imaging mass cytometry (IMC) revealed that B4M3 treatment reshaped the TME, increased cytotoxic T lymphocyte (CTL) infiltration, and reduced regulatory T cells (Tregs). Mechanistically, B4M3 therapy upregulated TGF-β, promoting Th17 differentiation and CTL recruitment, thereby enhancing anti-tumor immunity. Our findings demonstrate that B4M3 CAR-T cells effectively address antigen heterogeneity and enhance therapeutic efficacy in OC, thereby offering a promising strategy for solid tumor immunotherapy.

The renin-angiotensin system is a key regulator of blood pressure homeostasis, with its primary effector, the angiotensin II type 1 receptor (AT1R), mediating vasoconstriction and processes fundamental to cancer progression, including proliferation, angiogenesis, and metastasis. Elevated AT1R expression is consistently linked to poor prognosis and therapeutic resistance across various malignancies. Preclinical studies provide compelling evidence that AT1R activation drives key cancer related processes, while its inhibition by angiotensin receptor blockers (ARBs) suppresses tumour growth, induces apoptosis, reduces angiogenesis, and inhibits metastasis across a wide range of cancer models. Critically, ARBs effectively modulate the tumour microenvironment (TME), alleviating fibrosis, promoting anti-tumour immune cell phenotypes, and enhancing the efficacy of targeted therapies, chemotherapies, and immunotherapies. Despite this strong preclinical evidence and supporting retrospective population studies, clinical translation of ARBs in oncology remains inconsistent, with trials often limited by design, patient heterogeneity, and supra-therapeutic ARB dosages required for acute anti-cancer effects. This review seeks to summarise the current understanding of AT1R's role in cancer, highlight preclinical and clinical investigations of targeting RAS, and suggest further strategies to unlock its therapeutic potential. Realising the full therapeutic promise of AT1R targeting in oncology requires a multifaceted approach, including the development of innovative delivery systems, such as TME-activated ARBs, and the exploration of advanced therapeutic modalities, such as antibody based AT1R inhibitors. Rigorously designed clinical trials that include biomarker-driven patient stratification to identify responsive cohorts are crucial to define the context-dependent role of AT1R and conclusively establish its clinical utility as a combinatorial strategy to enhance patient outcomes.

MDC1 is a key protein in DNA damage signaling. When DNA double-strand breaks (DSBs) occur, MDC1 localizes to the sites of DNA damage to promote the recruitment of other factors, including the 53BP1-mediated DSB repair pathway. By studying mechanisms of poly (ADP-ribose) polymerase inhibitor (PARPi) resistance in BRCA2; p53-deficient mouse mammary tumors, we identified a thus far unknown role of MDC1 in replication fork biology. Our results show that MDC1 localizes at active replication forks during normal DNA replication and regulates replication fork progression. It suppresses spontaneous fork reversal and regulates fork nucleolytic processing thereby promoting sensitivity to PARPi and cisplatin. In this way, MDC1 loss improves DNA damage tolerance and causes chemoresistance in BRCA1/2-deficient cells. We demonstrate that limiting MRE11 activity abolishes the reduced fork speed while MRE11 inhibition/depletion overcomes PARPi resistance in these cells. Overall, our data provides new insights into the role of MDC1 in replication fork progression that mediates PARPi- and cisplatin-induced DNA damage, in addition to its role in DSB repair.

Metastasis to distant organs represents the most fatal prognostic factor for colorectal cancer (CRC). The distant metastasis of tumor cells results from the collaborative effort of multiple subcellular structures, with dynamic cytoskeletal remodeling underlying this entire process. Here, we found that knockdown of KRT81 expression (shKRT81) inhibited the proliferation, invasion, and migration, while ectopic overexpression of KRT81 enhanced the CRC cells migration. Furthermore, we identified a potential downstream effector of KRT81, ezrin, a member of the ezrin/radixin/moesin (ERM) protein family that regulates cell morphology and motility. Phenotypically, the shKRT81 attenuated ezrin protein expression and reduced the number and length of filopodia in CRC cells, which were restored when KRT81 was re-overexpressed. Mechanistically, KRT81 formed a complex with ezrin, and recruitment of ezrin to the membrane and phosphorylation at the Thr567 residue were significantly abolished in shKRT81 cells. Interestingly, we found that Myosin 1B (MYO1B) might provide the driving force for the recruitment of ezrin. Notably, combinatorial inhibition (shKRT81 + ezrin-specific inhibitor) exerted significantly greater suppression of CRC cell migration and invasion than either intervention alone. Consistently, KRT81 expression was increased in CRC, and relatively high expression of KRT81 was associated with a poor prognosis. In summary, we identified a novel regulatory axis that involves KRT81, MYO1B, and ezrin, which regulates filopodia formation and migration behavior in CRC. Therefore, KRT81 may serve as a therapeutic target for CRC.

While third-generation EGFR tyrosine kinase inhibitors (EGFR-TKIs), such as osimertinib, have significantly improved patient survival in non-small cell lung cancer (NSCLC), acquired resistance remains a major clinical challenge, and its underlying mechanisms are incompletely understood. In this study, we demonstrate that YTHDC2 expression is significantly downregulated in osimertinib-resistant patient-derived xenograft (PDX) tissues and lung cancer cell lines compared to their osimertinib-sensitive counterparts. Further investigation revealed that YTHDC2 overcomes osimertinib resistance in lung cancer cells by promoting cuproptosis. Mechanistically, YTHDC2 binds to m⁶A-modified sites (specifically at nucleotides A1223 and A2824) within the mRNA of the copper transporter SLC31A1 in an m⁶A-dependent manner. This interaction enhances SLC31A1 mRNA stability and protein expression, thereby increasing intracellular copper transport and inducing cuproptosis in tumor cells. Additionally, we found that the copper ionophore disulfiram (DSF) overcame osimertinib resistance by augmenting YTHDC2 expression. Collectively, our findings elucidate a novel YTHDC2-SLC31A1-cuproptosis axis as a key mechanism underlying EGFR-TKI resistance and propose new therapeutic strategies for its reversal.

The Polycomb group (PcG) protein chromobox 8 (CBX8) is the subunit of Polycomb repressive complex 1 (PRC1) and recognizes the trimethylation of histone H3 on Lysine 27 (H3K27me3), and coordinates with PRC2 complex to function as an epigenetic gene silencer. CBX8 plays a key role in cell proliferation, stem cell biology, cell senescence, and cancer development. However, the post-translational modifications of CBX8 remain poorly understood. Here, we report that protein kinase D1 (PKD1) interacts and phosphorylates CBX8 at Thr234 and Ser256 /311 residues. PKD1-mediated CBX8 phosphorylation at Thr234 reduced its expression level by promoting its ubiquitination-mediated degradation, whereas Ser256/311 phosphorylation decreased CBX8 binding to other PRC1 components BMI1 and RING1A. Overall, CBX8 phosphorylation by PKD1 impaired PRC1 complex integrity and activity, mitigated H2AK119ub1 level, caused the upregulation of multiple target genes repressed by CBX8, and decreased CBX8, H2AK119ub1, and H3K27me3 enrichment at INK4A/ARF locus, thereby derepressing p16^INK4A and facilitating cellular senescence. Collectively, these results suggest that PKD1-mediated CBX8 phosphorylation at T234 and S256/311 is a key mechanism governing CBX8 function, including cell senescence.