Colorectal Cancer
Copyright ©2005 Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. May 28, 2005; 11(20): 3051-3055
Published online May 28, 2005. doi: 10.3748/wjg.v11.i20.3051
Antitumor effects and radiosensitization of cytosine deaminase and thymidine kinase fusion suicide gene on colorectal carcinoma cells
De-Hua Wu, Li Liu, Long-Hua Chen
De-Hua Wu, Long-Hua Chen, Department of Radiation Oncology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong Province, China
Li Liu, Institute of Cancer Research, Southern Medical University, Guangzhou 510515, Guangdong Province, China
Author contributions: All authors contributed equally to the work.
Correspondence to: De-Hua Wu, Department of Radiation Oncology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong Province, China. wudh@fimmu.com
Telephone: +86-20-61642135 Fax: +86-20-61642131
Received: July 23, 2004
Revised: July 24, 2004
Accepted: August 23, 2004
Published online: May 28, 2005
Abstract

AIM: To investigate the killing effect and radiosensitization of double suicide gene mediated by adenovirus on colorectal carcinoma cells.

METHODS: Colorectal carcinoma cell line SW480 was transfected with adenovirus expression vector containing cytosine deaminase (CD) and thymidine kinase (TK) fusion gene. The expression of CD-TK fusion gene was detected by reverse transcriptase-polymerase chain reaction. The toxic effect of ganciclovir (GCV) and 5-fluorocytosine (5-FC) on infected cells was determined by MTT assay. The radiosensitization of double suicide gene was evaluated by clonogenic assay.

RESULTS: After prodrugs were used, the survival rate of colorectal carcinoma cells was markedly decreased. When GCV and 5-FC were used in combination, the cytotoxicity and bystander effect were markedly superior to a single prodrug (χ2 = 30.371, P<0.01). Both GCV and 5-FC could sensitize colorectal carcinoma cells to the toxic effect of radiation, and greater radiosensitization was achieved when both prodrug were used in combination.

CONCLUSION: CD-TK double suicide gene can kill and radiosensitize colorectal carcinoma cells.

Keywords: CD-TK, Suicide gene, Radiosensitization, Colorectal carcinoma