Effect Of Curcumin Ⅲ On Xenografted Tumor Growth And Angiogenesis Of Human Lung Adenocarcinoma Cell Line A549 In Nude Mice

Lung cancer is an important cause of morbidity and mortality worldwide. Studies have shown that angiogenesis is closely correlated with the growth and metastasis of malignant tumors. Angiogenesis is a crucial event in the growth and invasion. Therefore, the targeting angiogenesis of cancer has been considered as an anti-cancer strategy to inhibit tumor growth and metastasis. In the recent years, oncologists have been focusing their studies on angiogenesis inhibitors. As a result, more than 35 types of angiogenesis inhibitors have been applied clinically. However, effect of curcumin III on the angiogenesis have not been performed thoroughly.Turmeric, belonging to the turmeric genus, is traditional Chinese herb. Curcumin is the active components of Curcuma longa L. Evidence has been showed that Curcumin can suppress tumor initiation, promotion and metastasis. The role of Curcumin has therefore engendered considerable interests in the prevention and therapy of cancer. The potential of curcumin arised from its anticancer ability to suppress proliferation of a wide variety of tumor cells, induce tumor cell apoptosis, down-regulate expression of transcription factors NF-κB and AP-1, and suppress angiogenesis. Curcumin contains three major components: curcumin Ⅰ(77%), curcumin Ⅱ(demethoxycurcumin,17%) and curcumin Ⅲ(bisdemethoxycurcumin, 3%), together referred to as curcuminoids. Recent studies showed that Curcumin Ⅲ(bisdemethoxycurcumin) was the most effective component to inhibit the tumor initiation and development among the natural curcuminoids. The effect of curcumin Ⅲ on angiogenesis in vivo has not been showed in literature.In this study, we investigated the effect of curcumin Ⅲ on xenografted tumor growth and angiogenesis of human lung adenocarcinoma cell line A549 in nude mice and elucidated the possible mechanisms of anti-angiogenesis. Moreover, we explored the synergistic effect of curcumin Ⅲ and the conventional chemotherapy drug-cisplatin on the nude mice model with human lung adenocarcinoma cell line A549.Methods:1. Extract,separate and purify curcuminⅢ from turmeric by ethanol precipitation,Petroleum ether defattedness,column chromatography,acetone purification,etc. 2. The cultured A549 human lung adenocarcinoma cells (2.5×107 cells in 1.00 ml of serum free media) were injected in the upper back of each nude mice subcutaneously. 15 days after implantation, the tumor bearing mice were randomly divided into 5 groups, 5 mice in each group. They are control group,TNP-470 group, curcumin Ⅲ group, cisplatin group and curcumin Ⅲ+ cisplatin combining group.3. For histological examination, the tumor tissues were separated, fixed in 4% paraformaldehyde and embedded in paraffin. The 5-μm thick sections stained by H.E. were analyzed. The expressions of CD34,VEGF,VEGFR-1 and VEGFR-2 in tumor tissues of each group were detected by immunohistochemistry. Quantitative ELISA for serum VEGF was performed according to manufacturer's recommendations.Results: 1. Curcumin Ⅲ was obtained successfully,and the purification was 95.2% by HPLC.2. The mean volume and weight of xenografted tumor in Curcumin Ⅲ group was remarkablely lower than those in control group. Moreover, MVD in Curcumin Ⅲ group was also lower than that in control group, but did not differ from that of TNP-470 group.3. Curcumin Ⅲ markedly suppressed the expression of VEGF and its receptors, VEGFR-1 and VEGFR-2, in xenografted tumor tissues. Meanwhile, there was significantly decrease of serum VEGF level in Curcumin Ⅲ group compared with the control group.4. Cisplatin had no effect on the expression of VEGF,VEGFR-1 and VEGFR-2 of tumor cells and endothelial cells. However, the volume and weight of xenografted tumor in Curcumin Ⅲ+Cisplatin group were lower than Curcumin Ⅲ group and Cisplatin group, respectively.Conculsion:The approach of extraction, separation and purification of curcumin Ⅲ was of satisfactory result and convenient. Curcumin Ⅲ can significantly inhibit tumor growth and angiogenesis of tumor tissu...