Epigenetically upregulated oncoprotein PLCE1 drives esophageal carcinoma angiogenesis and proliferation via activating the PI-PLC?-NF-?B signaling pathway and VEGF-C/ Bcl-2 expression.
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ABSTRACT: BACKGROUND:Esophageal squamous cell carcinoma (ESCC) is one of the most lethal malignancies. Neovascularization during tumorigenesis supplies oxygen and nutrients to proliferative tumor cells, and serves as a conduit for migration. Targeting oncogenes involved in angiogenesis is needed to treat organ-confined and locally advanced ESCC. Although the phospholipase C epsilon-1 (PLCE1) gene was originally identified as a susceptibility gene for ESCC, how PLCE1 is involved in ESCC is unclear. METHODS:Matrix-assisted laser desorption ionization time-of-flight mass spectrometry were used to measure the methylation status of the PLCE1 promoter region. To validate the underlying mechanism for PLCE1 in constitutive activation of the NF-?B signaling pathway, we performed studies using in vitro and in vivo assays and samples from 368 formalin-fixed esophageal cancer tissues and 215 normal tissues with IHC using tissue microarrays and the Cancer Genome Atlas dataset. RESULTS:We report that hypomethylation-associated up-regulation of PLCE1 expression was correlated with tumor angiogenesis and poor prognosis in ESCC cohorts. PLCE1 can activate NF-?B through phosphoinositide-phospholipase C-? (PI-PLC?) signaling pathway. Furthermore, PLCE1 can bind p65 and I?B? proteins, promoting I?B?-S32 and p65-S536 phosphorylation. Consequently, phosphorylated I?B? promotes nuclear translocation of p50/p65 and p65, as a transcription factor, can bind vascular endothelial growth factor-C and bcl-2 promoters, enhancing angiogenesis and inhibiting apoptosis in vitro. Moreover, xenograft tumors in nude mice proved that PLCE1 can induce angiogenesis, inhibit apoptosis, and increase tumor aggressiveness via the NF-?B signaling pathway in vivo. CONCLUSIONS:Our findings not only provide evidence that hypomethylation-induced PLCE1 confers angiogenesis and proliferation in ESCC by activating PI-PLC?-NF-?B signaling pathway and VEGF-C/Bcl-2 expression, but also suggest that modulation of PLCE1 by epigenetic modification or a selective inhibitor may be a promising therapeutic approach for the treatment of ESCC.
SUBMITTER: Chen Y
PROVIDER: S-EPMC6320601 | biostudies-literature | 2019 Jan
REPOSITORIES: biostudies-literature
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