基于代谢产物分析的壮药国虾薄抗NSCLC活性成分及作用机制研究

Total saponins from Gocaekmbaw (Gynostemma pentaphyllum), the common herbal medicine of Zhuang ethnic group, did not show significant inhibition on A549 cell proliferation, whereas it inhibited the tumor growth in mice with Lewis lung carcinoma after oral administration of total saponins of G. pentaphyllum. However, it is not yet clear that what the anti-tumor constituents were and that how they inhibited non-small cell lung cancer (NSCLC). In this study, the absorbed components will be collected by reverted gut sac method and Caco-2 cell monolayer model. The SD rat serum, organ, urine and faeces after administration of total saponins of G. pentaphyllum will be collected and their ADMET will be analyzed by LCMS-IT-TOF and ACQUITY TQD UPLC-MS methods. The metabolites will be isolated and identified by chromatography and spectrometry. The differential gene expressions of A549 cell xenografts in BALB/c nude mice treated with and without total saponins of G. pentaphyllum will be compared by microarray analysis. The signaling pathway related to cell cycle and apoptosis will be identified and screened. The effects of the metabolites of total saponins on relevant signaling pathway will be verified and their mechanism will be analyzed by RT-PCR and immunohistochemistry methods. It will be verified that the anti-NSCLC mechanism of the active constituents of the metabolites using A549 cells. These results will provide a reliable scientific data for the development of new anti-tumor drugs.

壮族常用药国虾薄（绞股蓝）总皂苷在体外无明显的抑制A549细胞增殖作用，用其灌胃Lewis肺癌荷瘤小鼠后具有明显的抑制肿瘤生长作用。那么，抑制肿瘤的成分是什么及其如何起作用，尚不清楚。本研究拟对国虾薄总皂苷通过人源Caco-2细胞单层模型、小肠外翻法收集其可吸收的成分；通过灌胃国虾薄总皂苷，收集SD大鼠的血清、尿液、粪便及脏器；通过LCMS-IT-TOF及三重四级杆液质分析国虾薄总皂苷在SD大鼠中的体内过程，并利用色谱及波谱学方法分离、鉴定其代谢产物；通过全基因表达谱芯片分析方法，比较A549细胞BALB/c裸小鼠移植瘤模型组与国虾薄总皂苷处理组的基因表达差异谱，进而确认并筛选细胞周期与细胞凋亡涉及的信号转导路径；通过RT-PCR、免疫组化等方法，验证国虾薄总皂苷的代谢产物对相应信号通路的影响；并通过A549细胞，验证代谢产物中有效成分抗NSCLC的作用机制，为开发新型抗肿瘤药物奠定基础。

国虾薄总皂苷提取物对Lewis肺癌荷瘤小鼠具有抑制肿瘤生长能力，尤其是与顺铂联合用药是显示出明显的抑制肿瘤生长作用。从给药第3天开始，联合给药低剂量组增长幅度显著减小。给药9天后， 阳性药和联合给药组与模型组相比，肿瘤体积均具有显著减小（p < 0.01）；联合给药组与阳性药组相比，肿瘤体积显著减小（p < 0.01）。联合给药低剂量组的抑瘤率达90.55%，说明联合给药低剂量组效果最佳。给药组的脾指数有所升高，肺指数有所回调。顺铂组的肾指数降低，而联合给药低剂量组的肾指数有所回调。从国虾薄中共分离33个皂苷类化合物，其中14个化合物为新皂苷类化合物。前期筛查国虾薄皂苷对A549细胞抑制效果较强的化合物有damulin B、gypenosideL及gypenoside LI，其中前期研究发现damulin B诱导A549细胞凋亡，阻滞A549细胞于G0/G1期，抑制细胞侵袭转移；本次研究利用20位差向同分异构体gypenoside L与gypenoside LI进行研究，发现它们均诱导A549细胞凋亡并抑制其侵袭转移，但对A549细胞周期的抑制方面有所不同，gypenoside L阻滞A549细胞于G0/G1期，而gypenoside LI阻滞于G2/M期。表明绞股蓝皂苷因化学结构的不同而发挥的抗肿瘤作用不同，C-20位对其抗肿瘤活性具有较大的影响，仅因S/R构型的差异便能导致抗肿瘤作用的差异。这为多靶点抗肿瘤药物的发现提供了基础。