葫芦素B抗肝癌血管新生新机制：miR-214—VEGFR2/Bcl-2通路

Tumor growth is dependent on angiogenesis. Inhibiting angiogenesis is a new anti-tumor therapeutic strategy. Chinese herbal medicine is an important resource of our country, which has great potential and meaning to discover new antiangiogenic agents and study their molecular mechanisms. The applicant has discovered Cucurbitacine B (CuB),the index ingredient of the Cucurbitacin tablet,inhibited proliferation and induce apoptosis of endothelial cell, also suppressed the protein expression of VEGFR2 and Bcl-2 in HUVEC, inhibited angiogenesis of Chicken chorioallantoic membranes in vivo. MiR-214 has been reported to inhibit angiogenesis, down-regulation of miR-214 indicated high recurrent and poor prognosis of hepatocellular carcinoma. Bioinformatics predict that VEGFR2 and Bcl2 are both potential targets for miR-214 by Targetscan software and our previous experiments have demonstrated that miR-214 was increased after CuB treatment. So we hypothesized that CuB might up-regulate miR-214 to inhibit the expression of VEGFR2 and Bcl-2, which will suppress the proliferation and migration of endothelial cell, also will induce endothelial cell apoptosis. This present study was to investigate the new antiangiogenesis mechanisms of CuB in hepatocellular carcinoma by targeting miR-214, which has great significance to elucidate the molecular mechanism of herbal angiogenesis inhibitors and anti-tumor drug development.

肿瘤的生长依赖于血管新生，通过抑制血管新生抗肿瘤是新的肿瘤治疗策略。中草药是我国的重要资源，从中发现新的血管新生抑制剂，并研究其分子机制意义重大。申请者前期发现葫芦素片中指标成分葫芦素B（CuB）体外抑制内皮细胞增殖、促进凋亡、抑制VEGFR2和Bcl-2表达，体内抑制鸡胚绒毛尿囊膜血管生成。文献报道miR-214为血管新生抑制因子，其下调表征肝癌的高复发性和预后不良。我们通过targetscan预测VEGFR2、Bcl-2 是miR-214共同潜在靶点，并且验证CuB上调miR-214。提出假设：CuB通过上调miR-214，抑制VEGFR2和Bcl-2表达，从而抑制内皮细胞增殖，迁移，诱导内皮细胞凋亡，抗血管新生。本课题通过转染,慢病毒载体构建等方法探讨CuB靶向miR-214抑制肝癌血管新生，对阐明中药血管新生抑制剂抗肿瘤的分子机理以及新药研发意义重大。

葫芦素B是中药甜瓜蒂的主要有效成分，以其为质标成分的葫芦素片临床上已经用于肝癌的治疗，取得了较好的疗效，但是葫芦素片的抗癌机制仍不明确， 这就限制了它的临床应用和进一步开发。本课题经过调整，主要内容如下：（1）葫芦素B具有抗血管新生作用；（2）葫芦素B通过抑制VEGF/VEGFR2/JAK/STAT3通路抗血管新生；（3）长期暴露于双酚A中，大鼠肝细胞ROS水平升高，过氧化氢酶活力由最初的升高转为下降，肝细胞损伤。这有可能成为肿瘤血管新生的致病因素。抑制新生血管药物不仅仅用于肿瘤的治疗，还可以用于其它如感染、糖尿病、多发性硬化症等血管生成相关的疾病，本研究也为增加葫芦素类药品临床适应症提供有益的方向。