生长抑素对人肝癌HepG2细胞增殖及cyclinD1、cyclinE蛋白表达的影响

目的探讨生长抑素治疗肝癌的作用机制。方法取对数生长期HepG2细胞以不含血清的培养液使其周期同步化，以含血清培养液继续培养24h后随机分为观察Ⅰ、Ⅱ、Ⅲ组及对照组，前三组分别加入质量浓度为100、200、400μg／（kg·d）的生长抑素，对照组加入等体积RPMll640培养液24—72h。MTT比色法观察各组细胞增殖抑制率，流式细胞仪检测细胞周期分布，免疫组化法检测周期素D1（cyclinD1）、周期素E（cyclinE）蛋白表达。结果观察Ⅰ、Ⅱ、Ⅲ组不同时间点细胞增殖抑制率均显著高于对照组，且同一时间点观察Ⅲ组〉观察Ⅱ组〉观察I组，同组中72h〉48h〉24h（P〈0．05、0．01）；观察Ⅰ、Ⅱ、Ⅲ组G，期细胞比例均显著高于对照组，观察Ⅱ、Ⅲ组S期细胞比例均显著低于对照组（P〈0．05、0．01）；观察Ⅰ、Ⅱ、Ⅲ组cyclinD1、cyclinE蛋白水平均显著低于对照组，且观察Ⅲ组〈观察Ⅱ组〈观察Ⅰ组（P〈0．05、0．01）。结论生长抑素可通过下调cyclinD1、cyclinE表达抑制HepG2细胞增殖，此可能为其治疗肝癌的作用机制之一。

Effects of somatostatin on proliferation and expression of cyclinD1 and cyclinE in hepatoma cell line HepG2

Objective To investigate the mechanism of somatostatin for treating hepatoma. Methods HepG2 cells in logarithmic growth phase were obtained and cultured to be celt cycle synchronization with serum-free medium, then cultured with medium for 24 hs and divided randomly to observed groups Ⅰ , Ⅱ, Ⅲ and control group, the former three groups were treated with somatostatin at concentrations of 100,200 and 400 μg/（ kg·d） respectively,and the control group treated with RPMI1640 culture medium for 24-72hs. The cell proliferation inhibition rate（CPIR） in all groups was detected by MTT assay ,cell cycle distribution was observed by flow eytometr,eyclin D1 and eyclin E protein expression were detected by immunohistochemistry assay. Results CPIR in observed groups Ⅰ , Ⅱ, Ⅲ at different times were significantly higher than those in the control group, and CPIR in observed group Ⅲ 〉 group Ⅱ 〉 group Ⅰ at the same time, CPIR at 72 h 〉 48 h 〉 24 h in the same group（P 〈 0.05,0.01 ）. The percentage of G1 phase cells in observed groups Ⅰ , Ⅱ, Ⅲ were significantly higher than that in the control group, the percentage of S phase cells in observed groups Ⅱ and Ⅲ were significantly lower than that in the control group（ P 〈 0.05,0.01 ）. cyclin D1 and cyclin E protein level in observed groups Ⅰ , Ⅱ , Ⅲ were significantly lower than that in the control group, and which in observed group Ⅲ〉 group Ⅱ 〉 group Ⅰ at the same time （ P 〈 0.05, 0.01 ）. Conduslons Somatostatin can inhibit the proliferation of hepatoma cell line HepG2 by down-regulating the expression of cyclin D1 and cyclin E,which maybe its mechanism for treating hepatoma.