[Effects of Zengmian Yiliu Recipe combined cisplatin on the tumor inhibition rate in platinum-resistant ovarian cancer].

Objective: To observe the effects of Zengmian Yiliu Recipe (ZYR) combined cisplatin on the growth of subcutaneous tumor in nude mice with platinum-resistant ovarian cancer, and to explore its possible mechanisms.

Methods: The model of ovarian cancer subcutaneous tumor was established in nude mice using platinum-resistant ovarian cancer line COC1/DDP. The mice were randomly divided into six groups, i. e., the high Chinese materia medica (CMM) group, the medium CMM group, the low CMM group, the cisplatin group (DDP), the combined treatment group (with DDP combined CMM), and the control group (with normal saline). The medication lasted for 3 successive weeks. The tumor weight and the tumor inhibition rate were calculated. The expressions of Bcl-associated x protein (Bax) and B-cell lymphoma/leukemia-2 (Bcl-2) were detected using quantitative RT-PCR and immunohistochemical assay. The ultra-structure of tumor cells was observed by electron microscopy.

Results: The tumor inhibition rate was the highest in the combined treatment group, being (59. 26 +/- 6.86) %, showing statistical difference when compared with the rest groups (P < 0.01). Results of RT-PCR showed the Bax mRNA expression was the highest in the combined treatment group and the lowest in the control group (P < 0.01). Anti-apoptotic gene Bcl-2 mRNA expression was the highest in the control group and the lowest in the high CMM group (P < 0.01). The Bcl-2 mRNA expression was lower in the combined treatment group than in the cisplatin group (P < 0.01). Immunohistochemical results showed the Bax protein expression was the highest and the expression of Bcl-2 was the lowest in the combined treatment group, showing statistical difference when compared with the rest groups (P < 0.01). The middle- and late-stage manifestations of apoptosis could be seen in each CMM group and the combined treatment group under electron microscope.

Conclusions: ZYR combined with chemotherapy could reverse the cisplatin-resistance of resistant ovarian cancer nude mice, and enhance its tumor inhibitory effect. Its mechanisms were correlated with up-regulating the expression of Bax, down-regulating the expression of Bcl-2, and promoting cisplatin resistant ovarian cancer cell apoptosis.