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World J Gastroenterol. Feb 14, 2007; 13(6): 934-938
Published online Feb 14, 2007. doi: 10.3748/wjg.v13.i6.934
Growth inhibitory effect of wild-type Kras2 gene on a colonic adenocarcinoma cell line
Hong Li, Hou-Fa Cao, Jun Wan, Yuan Li, Mei-Ling Zhu, Po Zhao
Hong Li, Hou-Fa Cao, Inpatient Department of Medical Health Center, Chinese PLA General Hospital, Beijing 100853, China
Jun Wan, Yuan Li, Mei-Ling Zhu, Department of Nanlou Digestion, Chinese PLA General Hospital , Beijing 100853, China
Po Zhao, Department of Pathology, Chinese PLA General Hospital, Beijing 100853, China
Author contributions: All authors contributed equally to the work.
Supported by a grant from National Natural Science Foundation of China for Young Scholars, No. 30200326
Correspondence to: Dr. Po Zhao, Department of Pathology, Chinese PLA General Hospital, Beijing 100853, China. zhaopo@301hospital.com.cn
Telephone: +86-10-66937736
Received: December 1, 2006
Revised: December 10, 2006
Accepted: January 13, 2007
Published online: February 14, 2007
Abstract

AIM: To observe the growth inhibitory effect of wild-type Kras2 gene on a colonic adenocarcinoma cell line Caco-2.

METHODS: Recombinant plasmid pCI-neo-Kras2 with wild type Kras2 open reading frame was constructed. The Caco-2 cells were transfected with either pCI-neo or pCI-neo-Kras2 using Lipofectamine 2000. The expression of wild type Kras2 was examined by Northern blot analysis. And the expression of wild type Kras2 protein was examined by Western blot analysis. The effects of wild-type Kras2 on cell proliferation were analyzed by monotetrazolium (MTT) assay, meanwhile analyses of cell cycle and spontaneous apoptosis rate were carried out by flow cytometry (FCM).

RESULTS: The plasmid of pCI-neo-Kras2 was successfully established. The growth rate of cells transfected with pCI-neo-Kras2 was significantly lower than the control cells transfected with the empty pCI-neo vector (P < 0.05). Cell cycle analysis revealed arrest of the pCI-neo-Kras2 transfected cells in G0/G1 phases, decreased DNA synthesis and decreased fractions of cells in S phase. The proliferative index of cells transfected with pCI-neo-Kras2 was decreased compared with the control cells (49.78% vs 64.21%)，while the apoptotic rate of Caco-2 cells with stable Kras2 expression increased (0.30% vs 0.02%).

CONCLUSION: The wild-type Kras2 gene effectively inhibits the growth of the colonic adenocarcinoma cell line Caco-2.

Keywords: Colonic adenocarcinoma; Wild-type Kras2; Cell cycle; Apoptosis