牡荆属药用植物中基于雄激素轴和细胞凋亡通路的多靶点抗前列腺癌活性成分及其作用机制研究

Prostate cancer is the most commonly diagnosed malignancy in the male genitourinary system. Patients with advanced prostate cancer invariably relapse with the most aggressive form of this disease, known as castration-resistant prostate cancer (CRPC) with high death rate. Clinical efficacious agents for CRPC remain urgently needed. Reactivation of the androgen axis due to changes in androgen receptor (AR) signaling and adaptive intratumoral androgen biosynthesis plays a vital role in the initiation and progression of CRPC, which makes AR and AKR1C3 (aldo-keto reductase 1C3, also known as type 5 17β-hydroxysteroid dehydrogenase) to be the promising therapeutic targets for CRPC. In our previous investigations, we found that phenylnaphthalene-type lignans were the characteristic bioactive constituents from Vitex species, which can significantly induced apoptosis of androgen-independent prostate cancer cells and inhibited the expression and function of AR and AKR1C3, with low toxicity against human normal prostate epithelial cells, proposing that this type of compounds can exert antitumor activity by multi-targeting the androgen axis and apoptosis pathway in CRPC. Our research project is therefore conducted to perform the bioassay-guided rapid isolation and detection of the phenylnaphthalene-type lignans from Vitex medicinal species with combined use of TLC and NMR. Then we evaluate the comprehensive anti-CRPC efficacy of these constituents using both in vitro and in vivo CRPC models, reveal the structure-activity relationship (SAR) and demonstrate their mechanisms focused on the androgen axis signal pathway and apoptosis pathway, providing scientific basis for the anti-CRPC new drug development and the fully utilization of Vitex medicinal resource.

前列腺癌是男性常见恶性肿瘤，多数患者最终转变为去势抵抗性前列腺癌（CRPC），死亡率高，临床缺乏有效治疗药物。雄激素受体（AR）信号通路改变和肿瘤内雄激素合成导致雄激素轴再激活是CRPC发生发展的关键因素，因此AR和雄激素合成酶AKR1C3成为治疗CRPC的重要靶标。我们在对牡荆属植物活性成分的研究中，首次发现其中特有的苯代萘型木脂素具有诱导激素非依赖性前列腺癌细胞凋亡、抑制细胞AR与AKR1C3表达和功能的多重作用，且对前列腺上皮细胞毒性小，提示该类成分可能通过干预雄激素轴和细胞凋亡通路的多个靶点发挥抗癌作用。本项目拟应用TLC和NMR快速识别检测方法，对牡荆属药用植物苯代萘型木脂素进行活性导向追踪分离；采用CRPC细胞和动物模型，评价该类成分药效、探讨构效关系；结合雄激素轴和凋亡信号通路阐明其抗癌作用机制及靶点。本项目的实施完成将为抗CRPC药物发现和牡荆属药用资源的开发利用奠定基础。

前列腺癌是男性常见恶性肿瘤，多数患者最终转变为去势抵抗性前列腺癌（CRPC），死亡率高，临床缺乏有效治疗药物。我们在对牡荆属植物活性成分的研究中，首次发现其中特有的苯代萘型木脂素可显著抑制多种人前列腺癌细胞（激素依赖和非依赖）增殖、诱导前列腺癌细胞凋亡，且对前列腺上皮细胞毒性小，提示该类成分选择性好，具有开发成理想抗前列腺癌药物的潜能。本项目从5种牡荆属药用植物（黄荆、牡荆、单叶蔓荆、三叶蔓荆和莺哥木）中共分离鉴定化合物118个，主要包含木脂素和二萜两类特征性成分。应用TLC和NMR快速识别检测方法，对牡荆属药用植物苯代萘型木脂素进行追踪分离，鉴定了包括黄荆子素VNL等17个代表性成分；采用CRPC细胞和动物模型，评价了该类成分的体内外药效、并探讨构效关系，发现黄荆子素VNL效果最佳，体内可显著抑制3种人前列腺癌（C4-2、22RV1和Lncap去势抵抗）小鼠移植瘤的生长，抑瘤率分别为47.2%、46.7%和70.3%，与阳性药MDV3100效果相当，且与MDV3100联用效果更优，提高肿瘤抑制率的同时、降低给药剂量；进一步采用化学生物学研究方法阐明黄荆子素VNL的作用靶点为甲基巴豆酰辅酶A羧化酶2（methycrotonyl CoA carboxylase 2，MCCC2），VNL为目前报道的第一个MCCC2天然拮抗剂，Kd值为11.02nM。结合初步的转录组学研究表明，VNL通过直接结合MCCC2干预肿瘤细胞的细胞周期信号通路而发挥抗前列腺癌药效。此外，还从牡荆属植物的另一类特征性成分二萜类化合物中筛选得到一个具有显著抗前列腺癌活性成分negundoin G，可同时作用于p53和MAPK信号通路诱导细胞G2期阻滞和凋亡，显著抑制前列腺癌细胞生长。本项目的实施完成为具有自主知识产权抗前列腺癌药物的新药研发提供了药效确切且作用机制新颖的活性先导化合物，并为牡荆属药用资源的进一步开发利用奠定了良好的物质基础。.