Experimental Research About The Effect Of Recombinant Human Endostatin Combined With Curcumin On Treating Subcutaneous Xenograft H22 Liver Cancer Cell Model In Mice

Background and Purpose: Hepatocellular carcinoma(HCC) is a common malignant tumor nowadays, so it is still a hot topic to investigate and explore novel and effective anti-tumor drugs or therapeutic regimens. Endostar, the recombinant human endostatin, exerted effective anti-tumor activity in the treatment of hepatocellular carcinoma(HCC). Curcumin can exert a wide range of pharmacological activities, such as inhibiting tumor cell proliferation, inducing tumor cells apoptosis, and anti-angiogenesis. The anti-tumor activity of curcumin was also reported in the treatment of HCC. However, clinical therapeutic schedule commonly carry out the combination scheme instead of sole drug to improve the curative effect. Up to now, there are no reports about the combination of Endostar and curcumin for the treatment of HCC. Therefore, this study intends to investigate the effect of the combination of Endostar and curcumin on the growth of subcutaneous xenograft H22 liver cancer cell model in mice and its underlying mechanism, and to evaluate the anti-tumor effect of the combination scheme.Methods: Firstly, we investigated the effect of curcumin on the growth and proliferation of mouse liver caner cell line H22 by MTT assay and flow cytometry(FCM). Then the subcutaneous xenograft H22 liver cancer cell model in mice were established and divided into 4 groups(1.control group; 2.Endostar group; 3.curcumin group; 4. the combination group). After treatments, we measured the growth of xenograft, detected the tumor microvessel density and the expression levels of VEGF by immunohistochemistry method, and analyzed the expression of VEGFR2(KDR/Flk-1)and death receptor DR5 and anti-apoptotic protein Bcl-2 by Western blotting.Results: Experimental results demonstrated that curcumin can inhibit the growth and proliferation of mouse liver caner H22 cells in a time- and concentration-dependent manner. Besides, curcumin can induce apoptosis of mouse liver caner H22 cells. Compared with Endostar or curcumin alone, the combination of Endostar and curcumin can further inhibit the growth of subcutaneous xenograft H22 liver cancer cell model in mice, and significantly reduce the level of VEGF expression and the density of tumor microvessel. Furthermore, in the molecular level, the combination of Endostar and curcumin can effectively inhibit the expression levels of VEGFR2(KDR/Flk-l) and anti-apoptotic protein Bcl-2, and significantly increase the expression level of death receptor DR5.Conclusion: The combination of Endostar and curcumin can synergistically inhibit the growth of subcutaneous xenograft H22 liver cancer cell model in mice possibly by inhibiting angiogenesis and inducing tumor cell apoptosis. Based on the preliminary experimental results in this study, we believe that if the effect can be supported by data from more animal experiments and clinical trials, the combination of Endostar and curcumin will be a novel and effective scheme for the targeted therapy of HCC.