乳源酪蛋白糖巨肽对结肠癌HT-29细胞中COX-2、iNOS、GST-π表达的影响

Effect of Casein Glycomacropeptide(CGMP) on COX-2,iNOS and GST-π Expression in HT-29 Cells

目的:研究乳源酪蛋白糖巨肽(casein glycomacropeptide,CGMP)对人结肠癌HT-29细胞增殖及细胞中环氧合酶-2(cyclooxyenase-2,COX-2)、诱导性一氧化氮合酶(induc ible nitric oxide synthase,iNOS)及谷胱甘肽-S-转移酶π(glutathione-S-transferaseπ,GST-π)表达的影响,为探讨CGMP作为功能性食品提供可靠的依据。方法:采用噻唑蓝(methyl thiazolyl tetrazolium,MTT)实验测定不同剂量CGMP作用12、24、48 h对结肠癌HT-29细胞增殖的抑制情况;在不同剂量CGMP作用HT-29细胞24 h后,通过逆转录聚合酶链反应扩增细胞中提取的COX-2 mRNA、iNOS mRNA、GST-πmRNA,用凝胶成像自动分析系统检测各扩增带COX-2 mRNA、iNOS mRNA、GST-πmRNA水平。结果:1)CGMP组对细胞的增殖均有抑制作用,其中10-4 mg/mL抑制效果最强,且呈现时间依赖性。2)低剂量的CGMP(10-5、10-4、10-3 mg/mL)可显著降低3种基因的表达。结论:CGMP可在一定程度上抑制HT-29细胞的增殖,并呈时间依赖性,同时CGMP能在mRNA水平上抑制COX-2、iNOS、GST-π的表达,进而降低3种基因蛋白的表达,从而进一步改善结直肠癌。

Objective: The effect of casein glycomacropeptide(CGMP) on cell proli feration and on the expression of cyclooxyenase-2(COX-2), inducib le nitrite oxide synthase(iNOS), and glutathione-S-transferase π(GST-π) in HT-29 cells was explored to provide a reliable basis for the use of CGMP as an ingredient in functional foods. Methods: HT-29 Cells were cultured with CGMP for 12, 24 and 48 h. The inhibition of HT-29 cells proliferation was measured by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay. The expression of COX-2, iNOS, and GST-π was detected by reverse transcriptionpolymerase chain reaction(RT-PCR) after the HT-29 cells were treated for 24 h. Results: 1) CGMP inhibited the proliferation of HT-29 ce lls in a time-dependent fashion, and the optimal concentration was 10-4 mg/mL. 2) Low doses of CGMP(10-5, 10-4 and 10-3 mg/mL) significantly reduced the expression of three genes. Conclusion: To some extent, CGMP can inhibit the proliferation of HT-29 cells in a time-dependent manner. The mechanism is associated with decreasing the expression of COX-2, iNOS and GST-π by CGMP and further improving human colorectal cancer.