Enhancement
by Hypoxia of Antisense VEGF165 Gene Expression in Esophageal
Cancer Cells
GUO
Wen-Zhong, RAN Yu-Liang, LIU Jun, YU Long, SUN Li-Xin, YANG Zhi-Hua*
( Cancer Institute, Chinese Academy Medical Science & Peking Union Medical
College, Beijing 100021, China )
Abstract To
demonstrate effects of antisense VEGF165 to suppress
esophageal cancer cells and to improve efficacy of the gene therapy of tumor by
using hypoxic environment, hypoxia response element (HRE) was cloned from
promoter of VEGF by PCR and employed to construct an eukaryotic
expression vector containing luciferase and antisense VEGF165
by using recombinant DNA techniques. The recombinant vectors were transfered
into esophageal cancer cells by lipofectin methods, and hypoxia inducible
reporter gene expression was determined by luminometer and the expression of
antisense VEGF was evaluated indirectly by ELISA that detected of VEGF.
The esophageal cells tansfected by antisense VEGF165 gene
were transplanted into nude mice, in order to evaluate the suppressive effect
of antisense VEGF165. Our results showed that, in vitro,
hypoxia increased expression of reporter gene to 3 780 % and enhanced greatly
expression of antisense VEGF. In vivo, the growth of esophageal
cancer cells transfected by antisense VEGF in the vector containing HRE
was suppressed more significantly, with suppression rate being 71.1%, than that
by the vector without HRE, whose inhibiting rate 56.1%. It was concluded that
antisense VEGF165 suppressed significantly growth of
esophageal cancer, and by using a gene expression vector containing HRE, the
expression of target genes could be regulated autonomously by hypoxic
environment of tumor and the efficiency of gene therapy could be greatly
improved.
Key words esophageal cancer; angiogenesis; hypoxia; VEGF
*Corresponding author: Tel,
86-10-87771740; Fax, 86-10-87771740; e-mail: [email protected]