ADENOVIRUS-BASED P53 GENE-THERAPY IN OVARIAN-CANCER

Mutations of the p53 tumor suppressor gene are the most common molecul ar genetic abnormality to be described in ovarian cancer. To determine the feasibility of mutant p53 as a molecular target for gene therapy in ovarian cancer, we constructed an adenovirus vector containing the wild-type p53 gene. The ability of this adenovirus construct (Ad-CMV-p 53) to express p53 protein was examined by Western blot analysis in th e H358 lung cancer cell line, which has a homozygous deletion of the p 53 gene. The ability of the adenovirus vector system to infect ovarian cancer cells was tested using an adenovirus containing the beta-galac tosidase reporter gene under the control of the CMV promoter (Ad-CMV-b eta gal). The ovarian cancer cell line 2774, which contains an Arg273H is p53 mutation, was infected with Ad-CMV-beta gal, and the infected c ells were assayed for beta-galactosidase activity after 24 hr. To test the ability of wild-type p53 to inhibit cell growth, the 2774 cell li ne was infected with Ad-CMV-p53 or Ad-CMV-beta gal, and the effect of these agents on the growth of 2774 cells was determined using an in vi tro growth inhibition assay, Western blot analysis of lysates from H35 8 cells infected with Ad-CMV-p53 showed expression of wild-type p53 pr otein. When 2774 cells were infected with Ad-CMV-beta gal at a multipl icity of infection (m.o.i,) of 10 PFU/cell, >90% of cells showed beta- galactosidase activity, demonstrating that these cells are capable of efficient infection by the adenovirus vector. Growth of 2774 cells inf ected with Ad-CMV-p53 was inhibited by >90% compared to noninfected ce lls. The ability of the adenovirus vector to mediate high-level expres sion of infected genes and the inhibitory effect of Ad-CMV-p53 on the 2774 cell line suggests that the Ad-CMV-p53 could be further developed into a therapeutic agent for ovarian cancer. (C) 1995 Academic Press, Inc.