姜黄素体内代谢产物-四氢姜黄素靶向cFLIP抗乳腺癌作用及机制研究

Promoting blood circulation by removing blood stasis is one of the basic principles of traditional Chinese medicine for treating malignant tumors. Turmeric in Chinese herbal medicine for activating blood circulation to dissipate blood stasis has been used for tumor treatment in the clinic. National Cancer Institute (NCI) have approved curcumin, the main active ingredient of turmeric, as the third generation of cancer chemoprevention. However, it has been demonstrated that curcumin has poor oral bioavailability and low plasma concentration. Therefore, it is difficult to explain how curcumin displays the pharmacological effects in human body and the mechanisms underlying curcumin’s activity. In the previous work, we confirmed that tetrahydrocurcumin (THC) which is a in vivo metabolite of curcumin had the inhibitory effect on the growth of human breast cancer in vitro and in vivo, and THC could induce death receptor-mediated apoptosis pathway by activating caspase-8. Based on these results, we firstly suggested that THC may be the genuine bioactive form of curcumin in vivo. Considering that cFLIP is a negative regulator of caspase-8, we proposed hypothesis that "THC shows the anti-tumor effect by targeting cFLIP activation death receptor pathway”. We will design an experiment to prove the hypothesis and further elucidate the underlying molecular mechanism both in vitro and in vivo. The result will explore the new approach of the anticancer effect of curcumin against the breast cancer and provides a reference for the study on the active ingredients from traditional Chinese medicine with poor bioavailability, which has important theoretical and realistic significance for modern Chinese medicine research.

活血化瘀法是恶性肿瘤中医治疗的基本法则之一，活血化瘀类中药姜黄在临床上可治疗肿瘤，姜黄素是其主要药效成分，美国国立肿瘤研究所（NCI）已将其列为癌症的第三代化学预防药物。然而研究表明，姜黄素口服给药后，血药浓度低，生物利用度差，体内发挥药效作用的物质形式及机制迄今尚未阐明。前期工作中我们通过体内外实验首次证实姜黄素体内代谢产物四氢姜黄素（THC）对人乳腺癌的生长具有明显抑制作用，并可通过激活caspase-8启动死亡受体凋亡途径。鉴于cFLIP是caspase-8活化的负性调节子，我们提出假设“THC在体内通过靶向作用于cFLIP激活死亡受体途径发挥抗肿瘤作用”，本项目拟设计实验予以验证，并从体内外水平深入探讨调控这一过程的分子机制，研究结果有望揭示姜黄素体内抗乳腺癌的药效形式及其作用靶标，为口服生物利用度低的中药药效成分研究提供借鉴，在中医药研究急需现代化的今天具有重大的理论和现实意义。

活血化瘀法是恶性肿瘤中医治疗的基本法则之一，活血化瘀类中药姜黄在临床上可治疗肿瘤，姜黄素是其主要药效成分，美国国立肿瘤研究所（NCI）已将其列为癌症的第三代化学预防药物，是一种潜在的新型抗乳腺癌药物。然而，姜黄素口服给药后，血药浓度低，生物利用度差，体内发挥药效作用的物质形式及机制迄今尚未阐明。因此，本课题提出CUR的主要还原型代谢产物——THC同样发挥抗乳腺癌作用的观点，并围绕“THC在体内通过靶向作用于cFLIP激活死亡受体途径发挥抗肿瘤作用”这一假说，深入探讨了THC的抗乳腺癌作用及其相关机制。研究发现，THC通过下调cFLIP蛋白表达而诱导人乳腺癌MCF-7、MDA-MB-231及MDA-MB-468细胞发生Fas介导的外源性凋亡。同时，THC通过激活AMPK及抑制NF-κB而下调cFLIP诱导MCF-7细胞发生外源性凋亡。此外，THC在体内和体外通过抑制cFLIP诱导三阴性乳腺癌MDA-MB-231及MDA-MB-468细胞发生外源性细胞凋亡。并且，cFLIP在人乳腺癌组织中表达较高，是THC抗乳腺癌的潜在作用靶点。此外，THC在体内和体外能够增强CUR诱导人乳腺癌细胞发生凋亡、自噬及内质网应激而发挥抗乳腺癌作用。本课题为THC抗乳腺癌的临床应用奠定了理论基础和科学意义。