PTPN3 Acts as a Tumor Suppressor and Boosts TGF-? Signaling Independent of its Phosphatase Activity
Ontology highlight
ABSTRACT:
SUBMITTER: Ms. Bo Yuan
PROVIDER: S-SCDT-EMBOJ-2018-99945 | biostudies-other |
REPOSITORIES: biostudies-other
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Project description:TGF-β controls a variety of cellular functions during development. Abnormal TGF-β responses are commonly found in human diseases such as cancer, suggesting that TGF-β signaling must be tightly regulated. Here, we report that protein tyrosine phosphatase non-receptor 3 (PTPN3) profoundly potentiates TGF-β signaling independent of its phosphatase activity. PTPN3 stabilizes TGF-β type I receptor (TβRI) through attenuating the interaction between Smurf2 and TβRI. Consequently, PTPN3 facilitates TGF-β-induced R-Smad phosphorylation, transcriptional responses, and subsequent physiological responses. Importantly, the leucine-to-arginine substitution at amino acid residue 232 (L232R) of PTPN3, a frequent mutation found in intrahepatic cholangiocarcinoma (ICC), disables its role in enhancing TGF-β signaling and abolishes its tumor-suppressive function. Our findings have revealed a vital role of PTPN3 in regulating TGF-β signaling during normal physiology and pathogenesis.
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Project description:Transforming Growth Factor b (TGF-b) controls a variety of cellular functions during development. Abnormal TGF-b responses are commonly found in human diseases such as cancer, suggesting that TGF-b signaling must be tightly regulated. Here we report that Protein Tyrosine Phosphatase Non-receptor 3 (PTPN3) profoundly potentiates TGF-b signaling independent of its phosphatase activity. PTPN3 stabilizes TGF-b type I receptor (TbRI) through attenuating the interaction between Smurf2 and TbRI. Consequently, PTPN3 facilitates TGF-b-induced R-Smad phosphorylation, transcriptional responses and subsequent physiological responses. Importantly, the leucine-to-arginine substitution at amino acid residue 232 (L232R) of PTPN3, a frequent mutation found in intrahepatic cholangiocarcinoma (ICC), disable the role to enhance TGF-b signaling and abolishes its tumor suppressive function. Our findings have revealed a vital role of PTPN3 in regulating TGF-b signaling during normal physiology and pathogenesis.
2019-03-27 | GSE127903 | GEO
Project description:Protein Tyrosine Phosphatase Non-receptor 3 Acts as a Tumor Suppressor and Boosts TGF-b Signaling Independent of its Phosphatase Activity
| PRJNA525769 | ENA
Project description:BACKGROUND:Long noncoding RNAs (lncRNAs) are emerging as critical regulatory elements and play fundamental roles in the biology of various cancers. However, we are still lack of knowledge about their expression patterns and functions in human colorectal cancer (CRC). METHODS:Differentially expressed lncRNAs in CRC were identified by bioinformatics screen and the level of MIR22HG in CRC and control tissues were determined by qRT-PCR. Cell viability and migration capacities were examined by MTT and transwell assay. Mouse model was used to examine the function and rational immunotherapy of MIR22HG in vivo. RESULTS:We systematically investigated the expression pattern of lncRNAs and revealed MIR22HG acts as a tumor suppressor in CRC. The expression of MIR22HG was significantly decreased in CRC, which was mainly driven by copy number deletion. Reduced expression of MIR22HG was significantly associated with poor overall survival. Silencing of MIR22HG promoted cell survival, proliferation and tumor metastasis in vitro and in vivo. Mechanistically, MIR22HG exerts its tumor suppressive activity by competitively interacting with SMAD2 and modulating the activity of TGF? pathway. Decreased MIR22HG promoted the epithelial-mesenchymal transition in CRC. Importantly, we found that MIR22HG expression is significantly correlated with CD8A and overexpression of MIR22HG triggers T cell infiltration, enhancing the clinical benefits of immunotherapy. CONCLUSION:MIR22HG acts as a tumor suppressor in CRC. Our data provide mechanistic insights into the regulation of MIR22HG in TGF? pathway and facilitates immunotherapy in cancer.
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Project description:Nuclear factor-κB (NF-κB) signaling contributes to human disease processes, notably inflammatory diseases and cancer. NF-κB has a role in tumorigenesis and tumor growth, as well as promotion of metastases. Mechanisms responsible for abnormal NF-κB activation are not fully elucidated; however, RelA phosphorylation, particularly at serine residues S536 and S276, is critical for RelA function. Kinases that phosphorylate RelA promote oncogenic behaviors, suggesting that phosphatases targeting RelA could have tumor-inhibiting activities; however, few RelA phosphatases have been identified. Here, we identified tumor inhibitory and RelA phosphatase activities of the protein phosphatase 2C (PP2C) phosphatase family member, PPM1A. We show that PPM1A directly dephosphorylated RelA at residues S536 and S276 and selectively inhibited NF-κB transcriptional activity, resulting in decreased expression of monocyte chemotactic protein-1/chemokine (C-C motif) ligand 2 and interleukin-6, cytokines implicated in cancer metastasis. PPM1A depletion enhanced NF-κB-dependent cell invasion, whereas PPM1A expression inhibited invasion. Analyses of human expression data revealed that metastatic prostate cancer deposits had lower PPM1A expression compared with primary tumors without distant metastases. A hematogenous metastasis mouse model revealed that PPM1A expression inhibited bony metastases of prostate cancer cells after vascular injection. In summary, our findings suggest that PPM1A is a RelA phosphatase that regulates NF-κB activity and that PPM1A has tumor suppressor-like activity. Our analyses also suggest that PPM1A inhibits prostate cancer metastases and as neither gene deletions nor inactivating mutations of PPM1A have been described, increasing PPM1A activity in tumors represents a potential therapeutic strategy to inhibit NF-κB signaling or bony metastases in human cancer.
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Project description:BackgroundFOXP3 has been discovered to be expressed in tumor cells and participate in the regulation of tumor behavior. Herein, we investigated the clinical relevance and biological significance of FOXP3 expression in human hepatocellular carcinoma (HCC).MethodsExpression profile of FOXP3 was analyzed using real-time RT-PCR, western blotting and immunofluorescence on HCC cell lines, and immunostaing of a tissue microarray containing of 240 primary HCC samples. The potential regulatory roles of FOXP3 were dissected by an integrated approach, combining biochemical assays, analysis of patient survival, genetic manipulation of HCC cell lines, mouse xenograft tumor models and chromatin immunoprecipitation (ChIP) sequencing.ResultsFOXP3 was constitutively expressed in HCC cells with the existence of splice variants (especially exon 3 and 4 deleted, ?3,4-FOXP3). High expression of FOXP3 significantly correlated with low serum ?-fetoprotein (AFP) level, absence of vascular invasion and early TNM stage. Survival analyses revealed that increased FOXP3 expression was significantly associated with better survival and reduced recurrence, and served as an independent prognosticator for HCC patients. Furthermore, FOXP3 could potently suppress the proliferation and invasion of HCC cells in vitro and reduce tumor growth in vivo. However, ?3,4-FOXP3 showed a significant reduction in the tumor-inhibiting effect. The inhibition of FOXP3 on HCC aggressiveness was acted probably by enhancing the TGF-?/Smad2/3 signaling pathway.ConclusionOur findings suggest that FOXP3 suppresses tumor progression in HCC via TGF-?/Smad2/3 signaling pathway, highlighting the role of FOXP3 as a prognostic factor and novel target for an optimal therapy against this fatal malignancy.
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