Jessie Qiaoyi Liang
The Chinese University of Hong Kong, China
Title: psiTPTE22-HERV functions as a tumor suppressor and is epigenetically down-regulated in gastric cancer
Biography
Biography: Jessie Qiaoyi Liang
Abstract
The novel gene psiTPTE22-HERV identified by us previously is a human-specifi c gene containing a human endogenous retrovirus (HERV) element and located adjacent to the gene psiTPTE22. psiTPTE22-HERV is ubiquitously expressed in normal adult tissues including stomach, but is frequently silenced/down-reguated in gastric cancer samples and cell lines.
Ectopic expression of psiTPTE22-HERV signifi cantly suppressed cell viability, clonogenicity and cell cycle progression, induced apoptosis, and inhibited migration and invasion of SGC7901 and MKN45 gastric cancer cells. psiTPTE22-HERV also signifi cantly suppressed subcutaneous tumorigenicity of SGC7901 cells in nude mice and metastasis in tail vein injection models. In contrast, knock-down of psiTPTE22-HERV in the gastric cancer MKN1 cells signifi cantly increased cell growth and migration ability, promoted cell cycle progress and inhibited cell apoptosis. Bisulfi te genomic sequencing results indicated that psiTPTE22-HERV was silenced in gastric cancers by promoter DNA methylation, and its expression could be restored by DNA methylation and histone deacetylase inhibitors. Quantifi cation results demonstrated that the promoter methylation level of psiTPTE22-HERV in primary gastric tumors are signifi cantly associated with shortened survival in gastric cancer patients from
two independent Chinese cohorts (both P<0.05) as shown by Cox regression and Kaplan-Meier survival analyses. psiTPTE22-HERV is a novel tumor suppressor that is commonly down-regulated by promoter methylation in gastric cancer, which may serve as a prognostic biomarker for gastirc cancer patients.