The Antitumor Effect of TPD52L2 Silencing on Oxaliplatin-Resistant Gastric Carcinoma Is Related to Endoplasmic Reticulum Stress In Vitro.

Yu Zhang,Xin Zhang,Jiapeng Xu,Hongbing Fu,Ziran Wei,Zunqi Hu,Weijun Wang,Dejun Yang,Hua Li

doi:10.1155/2022/4451178

Abstract

Tumor protein D52-like 2 or simply TPD52L2 belongs to the TPD52 family which has been implicated in a variety of human carcinomas. However, the TPD52L2 function in the gastric carcinoma oxaliplatin (OXA) resistance remains elusive. The main objective of this study is to evaluate the TPD52L2 effect in OXA-resistant gastric carcinoma cells in vitro. Oxaliplatin-resistant gastric carcinoma cells were generated in MGC-803 and SGC-7901 cells. siRNA-mediated knockdown of TPD52L2 was investigated in OXA-resistant MGC-803-OXA and SGC-7901-OXA cells. qRT-PCR was performed to assess the expression level of TPD52L2 mRNA. TPD52L2 protein expression level, apoptosis, and endoplasmic reticulum (ER) stress-associated proteins were identified via immunoblotting analysis. MTT assay was conducted for the evaluation of cell viability, while colony-forming activity was carried out via crystal violet staining. SGC-7901-OXA and MGC-803-OXA cells were found to be more resistant to OXA, as compared to the parental cell lines. The expression of TPD52L2 was found to be upregulated in OXA-resistant cells. Knockdown of TPD52L2 suppressed cell colony-forming potency, cell growth, and development in OXA-resistant cells. TPD52L2 knockdown also enhanced the PARP and caspase-3 cleavage. ER-associated proteins such as PERK, GRP78, CHOP, and IRE1α were found to be elevated in TPD52L2 knockdown cells. ER stress might be involved in TPD52L2 knockdown-induced apoptosis in OXA-resistant gastric carcinoma cells.

Highlights

Gastric carcinoma is considered to be one of the most commonly occurring malignancies in the digestive system
Expression of Tumor protein D52-like 2 (TPD52L2) was determined via qRT-PCR, normalized to GAPDH expression, and depicted as fold-change relative to the control siRNA group. (b) e protein expression level of TPD52L2 was determined through immunoblotting with GAPDH as the loading control. (c) Quantification of TPD52L2 protein level normalized to GAPDH
It is well known that the increasing level of glucose receptor protein 78 (GRP78), protein kinase RNA-like endoplasmic reticulum kinase (PERK), and inositol-requiring kinase 1α (IRE1α) revealed the occurrence of endoplasmic reticulum (ER) stress and CHOP induction which lead to apoptosis. These findings suggest that TPD52L2 knockdown in SGC-7901-OXA and MGC-803OXA cells cause cell death that might be correlated with the inhibition of gastric carcinoma cell proliferation (OXA resistant)

Summary

Introduction

Gastric carcinoma is considered to be one of the most commonly occurring malignancies in the digestive system. The incidence of gastric carcinoma has been observed to be decreasing, but its mortality rate remains higher than that of other cancer-associated deaths. A high mortality rate of this carcinoma is correlated with the increasing incidence of drug resistance and its bad prognosis [1]. An elevated TPD52 expression was found to be increasing colony formation, cell proliferation, and tumor migration/invasion [6, 7]. A decreased level of TPD52L2 expression elevates cell invasive ability, while suppressing cell proliferation and drug sensitivity against glioblastoma cancerous cells [9]. The TPD52L2 high expression and its correlation with the increasing resistance of chemotherapeutic drugs against gastric carcinoma remain elusive

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