生长抑素抑制人结肠癌细胞增殖的实验研究

目的：研究外源性生长激素（GH）和生长抑素（SS）对人结肠癌细胞株HT-29的影响，并探讨其作用机制。方法：人结肠癌细胞株HT-29分成正常对照组、生长抑素组（SS组）、生长激素组（GH组）和生长抑素＋生长激素组（GH＋SS组）。MTT法测定细胞抑制率，流式细胞仪测定细胞周期分布、增殖指数、凋亡率，RT—PCR方法测定bcl．2及baxmRNA水平。结果：生长抑素能够明显抑制人结肠癌细胞株HT-29增殖（P〈0．01）、降低S期和G2／M期细胞比例（P〈0．05）、降低增殖指数（PI）（P〈0．05）、促进细胞凋亡（P〈0．01）、降低bcl-2mRNA表达（P〈0．05）、提高baxmRNA表达（P〈0．01），生长激素则无明显作用。GH＋SS组表现与SS组相似。结论：生长抑素可能通过抑制GdG．期细胞进入S期和G2／M期以及促进细胞凋亡两种途径抑制体外培养的人结肠癌细胞株HT-29增殖。生长抑素可能是通过改变bax基因和bcl-2基因的表达影响肿瘤细胞的凋亡。生长激素对体外培养的人结肠癌细胞株HT-29无显著影响。

Inhibitory effects of somatostatin on the growth of human colonic carcinoma cell line HT-29

Objective To study the effects of somatostatin(SS) and growth hormone(GH) on the growth of human colonic carcinoma cell line HT-29, and its mechanism. Methods HT-29 cancer cell line was divided into 4 groups: control group, somatostatin group (SS group), growth hormone group (GH group), and somatostatin+growth hormone group (SS+GH group). The inhibition rates (IR) were determined by MTT assay. The cell cycle, proliferation index (PI) and apoptosis rate were determined by flow-cytometry. The mRNA expression of bax and bcl-2 was determined by RT-PCR. Results SS treatment restrained the proliferation of the cell line HT-29(P<0.01), depressed the cell ratio of S and G2/M phases(P<0.05), depressed the PI(P<0.05), promoted apoptosis(P<0.01), depressed the bcl-2 mRNA level(P<0.05)and elevated the bax mRNA level(P<0.01). There was no influence of GH on the growth of the human colonic carcinoma cell line HT-29. The results in SS+GH group were similar to those of the SS group. Conclusions Somatostatin could restrain the human colonic carcinoma cell line HT-29 growth by depressing cell proliferation and promoting apoptosis. The mechanism of somatostatin to promote apoptosis is probably to influnce the bax and bcl-2 mRNA expression. GH can not influence the human colonic carcinoma cell line HT-29 directly.