Construction of Wild-type p53 Gene Recombinant Expression Vector and Its Antitumorigenic Effects on Human Colon Adenocarcinoma Cells / 中国肿瘤生物治疗杂志

ABSTRACT

p53 gene is a 16-20 kb of cellular DNA located on the short arm of human chromosome 17 at position 17pl3.1. This gene encodes a 393-amino acid nuclear phosphoprotein which involves in the regulation of cell proliferation. Loss of normal p53 function is associated with the cell transformation in vitro and the development of neoplasms in vivo. More than one-half of human malignancies were shown to contain an altered p53 gene. Most p53 gene alterations are the missense mutations, giving rise to an altered protein. The inactivation of wild-type p53 is currently regarded as an important genetic pathway for haman carcinogenesis generated by endogenous factors and exogenous carcinogens, as well as several tumor viruses. To gain more insight into the functional role of wild-type p53 in human colo-rectal carcinoma, a 2. 1 kilobase human wild-type p53 cDNA with 5' and 3' untranslated sequences was cloned into the BamHI site of pREP9 (episomal mammalian expression vector) in sense orientation. We performed experiments to transfer wild-type p53 into human colon adenocarcinoma cell line (SW1116) harboring mutant p53 genes with electroporation method. We assessed G4I8-resistant clonal growth, cell growth properties and cell cycle pattern by flow cytometry. The results demonstrated that human wild type p53 gene can suppress the phenotype of SW1116 cell line. So gene therapy based on restoration of the defective or mutant p53 function plays an important role in colo-rectal cancer treatment.