巴豆生物碱对Lewis小鼠肺腺癌细胞生长和凋亡的影响及机制研究

Effect and mechanism of croton alkaloids on growth and apoptosis of lewis mice lung adenocarcinoma cells

摘要:

目的 通过研究巴豆生物碱（CA）对Lewis小鼠肺腺癌细胞生长及对凋亡相关蛋白（Survivin、Caspase-3、Bax）、YAP蛋白的调控作用，探讨CA对肺腺癌细胞生长和凋亡的影响及其具体的作用机制。方法 培养Lewis鼠源性肺腺癌细胞（LLC），复制小鼠皮下成瘤模型，分为5组，每组10只，分别为对照组、低剂量CA组、中剂量CA组、高剂量CA组及顺铂组。皮下成瘤1周后给予药物干预，第22天对5组小鼠取瘤称重，计算抑瘤率并通过光学显微镜观察各组病理形态学的变化，判断CA对瘤体生长的抑制作用；Western blotting检测Survivin、Caspase-3、Bax及YAP蛋白相对表达量；qRT-PCR法检测Survivin、Caspase-3、Bax及YAP mRNA相对表达量。结果 中剂量CA组和高剂量CA组小鼠的一般生存状态较对照组、低剂量CA组及顺铂组好。低剂量CA组、中剂量CA组、高剂量CA组及顺铂组肿瘤细胞出现不同程度细胞凋亡现象，对照组肿瘤细胞多为坏死细胞。低剂量CA组、中剂量CA组、高剂量CA组及顺铂组的抑瘤率分别是13.91％、14.83％、27.84％和68.45％，4组抑瘤率比较，差异有统计学意义（P <0.05），各组抑瘤率依次升高，顺铂组肿瘤生长最慢。不同剂量CA组中Survivin mRNA相对表达量低于对照组（P <0.05），CA剂量越高，Survivin mRNA相对表达量越低；而不同剂量CA组中Caspase-3和Bax mRNA相对表达量高于对照组（P <0.05），CA剂量越高，Caspase-3和Bax mRNA的相对表达量越高；各组YAP mRNA的相对表达量比较，差异无统计学意义（P >0.05）。结论 CA对Lewis肺腺癌小鼠瘤体生长有抑制作用，并引起细胞凋亡。CA通过促进Bax和Caspase-3表达及抑制Survivin表达来调控Lewis小鼠肺腺癌细胞凋亡；其调控机制可能是通过下调Survivin的表达，从而使得Survivin对Caspase-3的抑制作用减弱，而Bax上调可进一步激活Caspase-3，从而诱导Caspase级联效应促进细胞凋亡，为肺腺癌治疗提供了新思路。

Abstract:

Objective To explore the effects of croton alkaloids (CA) on the growth and pathomorphology of Lewis mice lung adenocarcinoma cells, and to research the regulation of apoptosis-related proteins (Bax, Survivin, Caspase-3) and YAP in Lewis mice lung adenocarcinoma cells. To discuss the effects of CA on growth and apoptosis of lung adenocarcinoma and its specific mechanism.Methods Lewis mouse-derived lung adenocarcinoma cells (LLC) were cultured，and subcutaneous tumorigenesis model of 50 mice were divided into control group, low dose group of CA, medium dose group of CA, high dose group of CA, and cisplatin group. After one week, given the drug intervention to the subcutaneous neoplasia. On the 22nd day, the effect of CA on LLC with calculating the tumor volume, tumor weight, tumor inhibition rate, and observing the changes of pathomorphology in each group was analyzed. Western blots and RT-PCR were used to detect the expression of apoptosis related proteins and genes Yap, Bax, Caspase-3, and Survivin to explore the mechanism of CA in promoting the apoptosis of lung adenocarcinoma cells.Results (1) The general survival status of mice in medium dose CA Group and high dose CA Group was better than that in control group, low dose group and cisplatin group. (2) HE staining: the tumor cells in low-dose CA Group, medium dose CA Group, high-dose CA Group and cisplatin group showed different degrees of apoptosis, while the tumor cells in the control group were mostly necrotic cells. (3) The tumor inhibition rates of low-dose CA Group, medium dose CA Group, high-dose CA Group and cisplatin group were 13.91%, 14.83%, 27.84%, and 68.45% respectively. The difference was statistically significant by analysis of variance (P < 0.05). The tumor inhibition rates of each group increased in turn, and the tumor growth of cisplatin group was the slowest. (4) The expression of Yap, Bax, Caspase-3, and Survivin was detected by RT-PCR and Western blot in each group. It found that the expression of Survivin in different doses of CA Group was lower than that control group (P < 0.05). The higher the dose of CA, the lower the expression of Survivin; The higher the CA dose, the higher the expression of Bax and Caspase-3 proteins (P < 0.05). YAP did not change significantly in each group and has not statistically significant. (5) Western blotting was used to detect the effect of group A and the groups with different doses of CA on the expression of apoptosis-related proteins. However, Bax and Caspase-3 were both higher than the group A at different doses of CA. The higher the CA dose, the higher the expression of Bax and Caspase-3 proteins. YAP did not change significantly in each group and was not statistically significant (P > 0.05).Conclusions CA can inhibit the growth of Lewis lung adenocarcinoma mice tumors and cause the apoptosis of cells. CA can induce the apoptosis of Lewis lung adenocarcinoma mice tumor cells by up-regulating the expression of protein and gene protein and gene expression, and the down-regulating the expression of survivin. The regulatory mechanism may be through down-regulation of Survivin expression, so that Survivin's inhibitory effect on Caspase-3 protein is weakened, and Bax up-regulation can further activate Caspase-3 protein, thereby inducing Caspase cascade effect to promote cell apoptosis, which provides new targets for lung adenocarcinoma treatment.