Basic Research of the Adenovirus-mediated hCTR1 Transfection on the Treatment of Cisplatin Resistant Cervical Cancer

Objective To induce cisplatin-resistant cervical squamous carcinoma cell line and investigate the drug resistant mechanisms and adenovirus trans-gene therapeutical treatment. Methods The cisplatin-resistant subline, designated C-33A/cis, was originated by growing parental C-33A cells with gradually increasing doses of cisplatin. The cytotoxicity of cisplatin was determined by CCK-8 assay, and the CTR1 expression was measured by Western blot. Subcutaneous xenograft cervical tumor model was established by cisplatin-resistant C-33A/cis cell line. Recombinant adenovirus ad-hCTR1 was transfected into tumor by intratumoral injection and combined with cisplatin chemotherapy. The changes in the volume of tumor were observed and the mice were executed at 10^th day after the last injection, and the expression of CTR1 in tumor tissues was detected by immunohistochemistry. Results Cisplatin-resistant cervical carcinoma C-33A/cis cells were successfully induced by gradually increased concentration of cisplatin. The cytotoxic IC₅₀ value of cisplatin on C-33A/cis had been upgraded from (1.86±0.08) to (8.11±0.21) μmol/L, while the CTR1 was found decreased by Western blot assay. Immunohistochemical analysis indicated that CTR1 expression was increased by intratumoral injection of adenovirus ad-hCTR1, and the tumor growth of C-33A/cis drug-resistant cervical carcinoma xenograft was inhibited by ad-hCTR1 transfection combined with cisplatin. Conclusion The combination therapy of ad-hCTR1 transfection and cisplatin was effective to inhibit the growth of drug-resistant C-33A/cis tumor.