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Reversal of Multidrug Resistance in Gastric Cancer Cells by E2F‐1 Downregulation In Vitro and In Vivo
Author(s) -
Yan LinHai,
Wang XiaoTong,
Yang Jie,
Kong FanBiao,
Lian Chao,
Wei WeiYuan,
Luo Wen,
Xie YuBo,
Xiao Qiang
Publication year - 2014
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.24652
Subject(s) - in vivo , downregulation and upregulation , multiple drug resistance , in vitro , e2f , cancer , cancer cell , cancer research , chemistry , pharmacology , biology , medicine , drug resistance , microbiology and biotechnology , cell cycle , biochemistry , gene
ABSTRACT Transcription Factor E2F‐1 plays a critical role in cell cycle regulation and other biological processes in cells. However whether or not it is involved in the multi‐drug resistance (MDR) process of gastric cancer has not been fully elucidated yet. To explore the role of E2F‐1 in the MDR process of gastric cancer in vitro and in vivo, a cisplatin‐resistant gastric cancer cell line with stable downregulation of E2F‐1 was established. E2F‐1 shRNA led to downregulation of endogenous E2F‐1 mRNA and protein. It significantly promoted the sensitivity of SGC7901/DDP cells to cisplatin, doxorubicin, and fluorouracil. Flow cytometry confirmed that the percentage of apoptotic cells increased after E2F‐1 downregulation. This notion was further supported by the observation that downregulation of E2F‐1 blocked entry into the S‐phase of the cell cycle. Furthermore, downregulation of E2F‐1 significantly increased intracellular accumulation of doxorubicin. In addition, we determined the in vivo effects of E2F‐1 small interfering RNA (shRNA) on tumor size, and apoptotic cells in tumor tissues were detected by deoxynucleotidyl transferase‐mediated dUTP‐biotin nick end labeling and hematoxylin and eosin staining. In molecular studies, semiquantitative RT‐PCR and western blotting revealed that E2F‐1 downregulation could inhibit expression of MDR1, MRP, Bcl‐2/Bax, c‐Myc, Skp2, Survivin, and Cyclin D1. In conclusion: E2F‐1 may be involved in regulating multiple signaling pathways in reversing MDR, suggesting that E2F‐1 may represent a novel target for gastric cancer therapy. J. Cell. Biochem. 115: 34–41, 2014. © 2013 Wiley Periodicals, Inc.