USP9X integrates TGF-β and hypoxia signalings to promote ovarian cancer chemoresistance via HIF-2α-maintained stemness
Ontology highlight
ABSTRACT: Widespread intraperitoneal metastases and chemoresistance render ovarian cancer the leading cause of gynecological malignancy–related deaths, wherein TGF-β signaling plays the pivotal role by promoting cancer stem cells (CSCs) activity. The activation mechanism and key protumorigeneic events downstream of TGF-β signaling remain incompletely understood. Here, we identify hypoxic tumor microenvironment as an initiator of TGF-β signaling to promote HIF-2α positive CSC-mediated chemoresistance in high-grade serous ovarian cancer (HGSOC). Mechanistically, deubiquitinase USP9X, as a TGF-β downstream effector, stabilizes HIF-2ɑ in a hydroxylation- and ubiquitylation-dependent manner, thus promoting stemness reprogramming. Hypoxia and TGF-β signals converge on USP9X-HIF-2ɑ axis via multi-level regulations, which in turn facilitates Smad/HIF responses. Clinically, USP9X expression correlates with TGF-β signatures, CSCs characteristics, EMT behaviors, and chemotherapy responsiveness, along with HIF-2ɑ. Antagonizing USP9X efficiently represses tumor formation, metastasis, CSCs occurrence, while increasing chemosensitivity in orthotopic tumors, patient derived xenograft (PDX), organoid, and chemoresistant cell models, in part via restricting TGF-β and hypoxia activities. This study deciphers the critical role of hypoxic niche in stimulating TGF-β signaling, and a downstream USP9X-HIF-2ɑ proteostatic regulatory axis in priming the HGSOC stemness, thereby provides novel targeting venues to counteract TGF-β signaling in CSCs and meliorate clinical chemoresistance.
Project description:Myocardial infarctions cause hypoxic injury to downstream tissue and a consequent fibrotic remodeling process to replace injured tissue with a scar. Scar formation occurs through phases of wound healing in which stimuli such as transforming growth factor-beta (TGF-β) drive cardiac fibroblasts to activate into a myofibroblast phenotype and deposit matrix molecules that form a scar. While this is necessary to repair injured tissue, excessive fibrosis commonly occurs which is correlated with heart failure. Therefore, defining cardiac fibroblast phenotypes under hypoxic stimuli and TGF-β is essential for understanding and treating pathological fibrosis. We robustly characterized fibroblast phenotype through immunofluorescence, quantitative RT-PCR, and proteomic analysis, after either TGF-β treatment or hypoxia durations that mimic acute hypoxic injury post-infarction. We find that hypoxic fibroblasts respond to low oxygen with increased hypoxia inducible factor 1 (HIF-1) but not HIF-2 activity by 4h. This is accompanied by increased gene and protein levels of VEGFA and LOX, respectively, which are both targets of HIF-1. Both TGF-β1 and hypoxia inhibit proliferation by 24h. While TGF-β1 treatment upregulated various fibrotic pathways, hypoxia causes a global reduction in protein synthesis, including collagen biosynthesis. This study discerns overlapping from distinctive outcomes of TGF-β1 and hypoxia treatment, which is important for elucidating their roles in fibrotic remodeling post-MI.
Project description:Microenvironment has been suggested as an important factor contributing to how the colorectal cancer cells escape therapy, but the exact mechanism leading to chemoresistance remains elusive. Here, through modeling in vitro by cocultivation of patient-derived cancer associated fibroblasts (CAFs) with cancer stem cells (CSCs), we show that CAFs-secreted TGF-β2 is a key stromal factor that coordinates with hypoxia to promote CSC stemness and resistance to chemotherapy. GLI2, a key transcription factor of Hedgehog pathway, was identified as both necessary and sufficient in this process in which TGF-β and hypoxia-inducible factor (HIF-1α) synergize to directly induce GLI2 expression. Conversely, CSC-secreted TGF-β is also important to support the growth of CAFs but instead induce death of normal fibroblasts, suggesting a reciprocal mechanism to selectively support the CAF-CSC interaction. Small molecule inhibition of both TGF-β and GLI2 effectively reversed the chemoresistance. Finally, expression of TGFB2/HIF1A/GLI2 gene signature as a functional readout of this resistance pathway defines worse clinical outcomes and predicts patients relapse. Our observations uncover a key role of TGF-β/HIF-1α/GLI2 in microenvironment-mediated chemoresistance and reveal novel biomarker and targeting strategies to identify and treat the high risk CRC patients.
Project description:Radioresistance is regarded as the main barrier to effective radiotherapy in lung cancer. However, the underlying mechanisms of radioresistance remain elusive. Here, we show that lysine-specific demethylase 4C (KDM4C) is overexpressed and correlated with poor prognosis in lung cancer patients. We provide evidence that genetical or pharmacological inhibition of KDM4C impairs tumorigenesis and radioresistance in lung cancer in vitro and in vivo. Moreover, we uncover that KDM4C upregulates TGFβ2 expression by directly reducing H3K9me3 level at the TGFβ2 promoter and then activates TGF-β/Smad/ATM signaling to confer radioresistance in lung cancer. Using tandem affinity purification technology, we further identify deubiquitinase USP9X as a critical binding partner which deubiquitinates and stabilizes KDM4C. More importantly, depletion of USP9X impairs TGF-β/Smad signaling and radioresistance by destabilizing KDM4C in lung cancer cells. Thus, our findings demonstrate that USP9X-mediated KDM4C deubiquitination activates TGF-β/Smad signaling to promote radioresistance, suggesting that targeting KDM4C may be a promising radiosensitization strategy in the treatment of lung cancer.
Project description:Deubiquitinating enzymes play crucial roles in various cellular activities, yet their involvement in central nervous system (CNS) vascularization and barrier function remains elusive. Canonical Wnt signaling is essential for proper CNS vascularization and barrier maintenance. Using a loss-of-function screening for Wnt signaling activity, we identified ubiquitin-specific peptidase 9 X-linked (USP9X) as a key regulator in brain endothelial cells (BECs). Endothelium-specific Usp9x knockout reduces Wnt-signaling activity, compromising CNS vascularization and barrier function during development. Activation of Wnt signaling rescues these defects. Mechanistically, we uncovered β-catenin as a direct substrate of USP9X, with USP9X catalyzing K48 polyubiquitin chains to stabilize β-catenin. In pathological models of impaired CNS vascular barrier function, including an intracerebral hemorrhage model and an oxygen-induced retinopathy model, loss of Usp9x intensifies barrier disruption, accentuating defects. This finding implicates USP9X as a critical regulator of CNS vascularization and barrier function through Wnt signaling, offering insights into CNS disease implications.
Project description:Deubiquitinating enzymes play crucial roles in various cellular activities, yet their involvement in central nervous system (CNS) vascularization and barrier function remains elusive. Canonical Wnt signaling is essential for proper CNS vascularization and barrier maintenance. Using a loss-of-function screening for Wnt signaling activity, we identified ubiquitin-specific peptidase 9 X-linked (USP9X) as a key regulator in brain endothelial cells (BECs). Endothelium-specific Usp9x knockout reduces Wnt-signaling activity, compromising CNS vascularization and barrier function during development. Activation of Wnt signaling rescues these defects. Mechanistically, we uncovered β-catenin as a direct substrate of USP9X, with USP9X catalyzing K48 polyubiquitin chains to stabilize β-catenin. In pathological models of impaired CNS vascular barrier function, including an intracerebral hemorrhage model and an oxygen-induced retinopathy model, loss of Usp9x intensifies barrier disruption, accentuating defects. This finding implicates USP9X as a critical regulator of CNS vascularization and barrier function through Wnt signaling, offering insights into CNS disease implications.
Project description:The global up-regulation of histone acetylation modification after the activation of the TGF-β signaling pathway raised the possibility that the differential expression of specific histone acetyltransferases or histone deacetylases may involve in the modulation of TGF-β-associated chemoresistance in CRC. To test this hypothesis, high-throughput mRNA sequencing (RNA-Seq) was performed to compare the expression profile between SW480 cells treated with or without TGF-β1.
Project description:The aim of the study was to elucidate which TGFB signaling pathway molecules are involved in the colon cancer chemoresistance. The PCR array used for this experiments was 84 Human TGF-β Signaling Targets (Cat. N. PAHS-235ZA, Qiagen)
Project description:Cancer stem cells (CSCs) drive tumor growth, metastasis, relapse, and chemoresistance. However, it’s unclear how lipid metabolism, especially sphingolipids metabolism, regulates CSCs and chemoresistance. In this study, we developed spontaneous tumor models expressing a Sox9-GFP transgenic reporter and demonstrated that cancer cells expressing high levels of SOX9 functioned as CSCs in both primary tumors and metastases. Transcriptomics analyses uncovered that SOX9high CSCs upregulate ABCA12 lipid transporter. Functionally, downregulation of ABCA12 impaired cancer stemness and chemoresistance of SOX9high cells. Through lipidomic analysis, we demonstrated that ABCA12 regulates SOX9 expression and cancer stemness by controlling ceramide abundance. Blocking ceramide hydrolysis using acid ceramidase inhibitor D-NMAPPD sensitized tumors to chemotherapy and prevented enrichment of SOX9high CSCs. These data suggest a potential strategy for targeting CSCs and overcoming chemoresistance. We further demonstrated that ceramide inhibits the YAP/TAZ signaling that is required for SOX9 expression in breast CSCs.
Project description:Pedro Vizán, Daniel S. J. Miller, Ilaria Gori, Debipriya Das, Bernhard Schmierer & Caroline S. Hill. Controlling long-term signaling: receptor dynamics determine attenuation and refractory behavior of the TGF-β pathway. Science Signaling 6, 305 (2013).
Understanding the complex dynamics of growth factor signaling requires both mechanistic and kinetic information. Although signaling dynamics have been studied for pathways downstream of receptor tyrosine kinases and G protein (heterotrimeric guanine nucleotide-binding protein)-coupled receptors, they have not been investigated for the transforming growth factor-β (TGF-β) superfamily pathways. Using an integrative experimental and mathematical modeling approach, we dissected the dynamic behavior of the TGF-β to Smad pathway, which is mediated by type I and type II receptor serine/threonine kinases, in response to acute, chronic, and repeated ligand stimulations. TGF-β exposure produced a transient response that attenuated over time, resulting in desensitized cells that were refractory to further acute stimulation. This loss of signaling competence depended on ligand binding, but not on receptor activity, and was restored only after the ligand had been depleted. Furthermore, TGF-β binding triggered the rapid depletion of signaling-competent receptors from the cell surface, with the type I and type II receptors exhibiting different degradation and trafficking kinetics. A computational model of TGF-β signal transduction from the membrane to the nucleus that incorporates our experimental findings predicts that autocrine signaling, such as that associated with tumorigenesis, severely compromises the TGF-β response, which we confirmed experimentally. Thus, we have shown that the long-term signaling behavior of the TGF-β pathway is determined by receptor dynamics, does not require TGF-β-induced gene expression, and influences context-dependent responses in vivo.