Garcinone C通过调控Stat3和4E-BP1抑制卵巢癌恶性生物学行为的分子机制

Ovarian cancer is the leading cause of death among malignancies of the female reproductive system, with a high rate of mortality worldwide. There is an urgent need to develop novel chemotherapeutic agents against ovarian cancer. In our previous studies, 36 xanthone derivatives were isolated from Garcinia oblongifolia Champ. and Garcinia mangostana L.. MTT assay showed that among all these 36 xanthone derivatives, garcinone C was the best candidate for inhibiting the proliferation of ovarian cancer cells. Little is known about the anti-cancer effects of garcinone C so far. We found that garcinone C significantly inhibited the cell viability and colony-formation ability of ovarian cancer and nasopharyngeal carcinoma cells in a time- and dose-dependent manner. Flow cytometry demonstrated that garcinone C arrested the cell cycle at the S phase. And a decrease in the expression levels of cell-cycle-related proteins (Cyclin B1, Cyclin D1, Cyclin E2, cdc2, and CDK7) was observed. Moreover, garcinone C inhibited the protein expression of oncogene Stat3, while stimulating the protein expression of tumor suppressor 4E-BP1. Bioinformatics analyses suggested that Stat3 and 4E-BP1 might be associated with malignant behaviors of ovarian cancer such as drug resistance and metastasis. Therefore, in this application, a scientific hypothesis is proposed that garcinone C inhibits malignant biological behaviors of ovarian cancer by modulating the expression of Stat3 and 4E-BP1. By means of in vitro and in vivo assays, we aim to illustrate the role and molecular mechanism of garcinone C in the inhibition of proliferation, metastasis and drug resistance in ovarian cancer. The impact of this application is to provide a natural lead compound and lay a solid foundation for developing new anti-cancer agents.

卵巢癌是致死率最高的女性生殖系统恶性肿瘤，急需寻求新型有效的临床候选化疗药物。Garcinone C是本课题组从36种xanthone类化合物中筛选出的对卵巢癌细胞增殖抑制最显著的单体化合物，其与肿瘤相关研究鲜有报道。我们研究发现garcinone C能显著抑制肿瘤细胞增殖，阻滞细胞周期并下调细胞周期相关蛋白表达。同时，该化合物显著下调癌基因Stat3的蛋白表达和上调抑癌基因4E-BP1的蛋白表达，而生物信息学分析表明Stat3和4E-BP1与卵巢癌耐药及转移等多种恶性生物学行为的调控显著相关。由此我们提出科学假设：garcinone C通过调控Stat3和4E-BP1而抑制卵巢癌的恶行生物学行为。本项目将通过细胞模型和动物模型阐明garcinone C对卵巢癌增殖、转移及耐药等方面的影响，并揭示其肿瘤抑制的分子机制。该研究成果将为卵巢癌治疗药物的研发提供候选先导化合物并奠定坚实研究基础。

卵巢癌是致死率最高的女性生殖系统恶性肿瘤，急需寻求新型有效的临床候选化疗药物。Garcinone C是本课题组从36种xanthone类单体化合物中筛选出的对卵巢癌细胞增殖抑制最显著的单体化合物，其与肿瘤相关研究鲜有报道。本项目研究发现garcinone C（文中缩写为SZ-NCI-C）可显著抑制人卵巢癌细胞系裸鼠皮下移植瘤的生长。MTS实验显示SZ-NCI-C显著抑制卵巢癌细胞的增殖活力，且这种抑制作用具有时间和浓度依赖性。克隆形成实验发现SZ-NCI-C可呈浓度依赖性地抑制卵巢癌细胞的平板克隆形成能力和软琼脂克隆形成能力。细胞周期实验结果提示SZ-NCI-C可以阻滞卵巢癌细胞HeyA8的细胞周期于G2/M期，阻滞SKOV3的细胞周期于S期。SZ-NCI-C还可诱导卵巢癌细胞HeyA8发生细胞衰老。Western blot实验发现SZ-NCI-C影响卵巢癌细胞中细胞周期相关蛋白、细胞自噬相关蛋白和其它作用通路相关蛋白的表达水平，并可能通过逆转NCALD、KCNN3、SLC7A11、CKAP2、GALNT4及HLA-DMA等卵巢癌恶性因子的表达而发挥其抗肿瘤功效；特别是前四个蛋白，能彼此互作并与癌基因蛋白STAT3和抑癌基因蛋白4E-BP1互作，形成SZ-NCI-C的潜在靶标作用网络，协同发挥抗肿瘤作用。上述研究结果为卵巢癌治疗药物的研发提供了候选先导化合物，为临床治疗卵巢癌提供了新的候选分子靶点，具有重要的理论和应用价值。