Objective: Radiotherapy is the mainstay of treatment for advanced cervical cancer and most cervical cancers have evidence of HPV (human papilloma virus) infection, which inactivates the p53 gene. The goal of this study was to determine the effect of combining radiotherapy and Adp53 infection on the growth of cervical carcinoma cells.
Methods: The silta cervical carcinoma cell line contains wild-type p53 and HPV 16 infection. The C33A cell line has a p53 mutation. The Adp53 recombinant adenovirus contains the cytomegalovirus promoter, wild-type p53 cDNA, and a polyadenylation signal in a minigene cassette inserted into the El-deleted region of a modified adenovirus 5. Transduction efficiency was assessed by using an adenovirus containing the Escherichia coli beta-galactosidase gene and expression of wild-type p53 in infected cells was evaluated by Western blot analysis. One group of cells was irradiated prior to infection, the other group received no irradiation, but were either infected with virus or mock-infected. Cells were analyzed for viability 1 to 7 days after infection by using the sulforhodamine B assay. The percentage of cells undergoing apoptosis was determined by using a TUNEL assay.
Results: Fifty percent of C33A cells were transduced with 5 muthplicities of infection of virus whereas SiHa cells required 25 multiplicities of infection. Adp53 expression was found 48 h after infection. In the cells treated with both radiation and Adp53 infection growth inhibition was increased compared with inhibition resulting with either treatment alone. The combination treatment also increased the percentage of cells undergoing apoptosis.
Conclusion: Combining radiotherapy with Adp53 infection increases the inhibition of growth of cervical cancer cells in vitro. This combination treatment has the potential of increasing efficacy and of therapy.