摘要
目的探讨磷脂酰肌醇3激酶(phosphatidylinositol 3-kinase,PI3K)抑制剂LY294002提高胃癌耐药细胞SGC7901/VCR和亲代细胞SGC7901对化疗药物敏感性的作用及其机制。方法MTT法分别检测胃癌细胞SGC7901和SGC7901/VCR对化疗药长春新碱(VCR)的敏感性;RT-PCR法和免疫细胞化学法检测LY294002处理前后多药耐药蛋白1(multidrug resistance protein-1,MDR1)和X染色体连锁的凋亡抑制蛋白(X-linked inhibitor of apoptosis,XIAP)基因和蛋白水平;Westernblot法检测LY294002处理前后细胞PKB总蛋白水平和磷酸化水平;并用流式细胞仪检测细胞的凋亡率。结果2×10-5mol·L-1 LY294002能明显增加SGC7901和SGC7901/VCR细胞对VCR的敏感性(P<0.01),其IC50分别由(0.20±0.03)和(8.09±0.60)mg·L-1降至(0.05±0.006)和(1.70±0.20)mg·L-1;降低细胞MDR1和XIAP的基因和蛋白水平;降低磷酸化PKB水平,而对其总蛋白水平无影响;LY294002联合VCR用药后细胞凋亡率明显高于单独VCR处理(P<0.01)。结论LY294002通过降低耐药基因MDR1和抗凋亡基因XIAP的表达,提高耐药和非耐药胃癌细胞对化疗药物的敏感性,此过程与抑制PI3K/PKB通路密切相关。
Aim To observe whether the inhibition of PI3K/PKB signal pathway by LY294002 [ PI3K path, way inhibitor] could improve the sensitivities of human gastric carcinoma cell line SGC7901 and SGC7901/ VCR to anti-cancer drugs. Methods The sensitivities of SGC7901 and SGC7901/VCR to chemotherapeutic drug VCR were detected by MTT. The MDR1 and XIAP mRNA expression levels were evaluated by semiquantitative RT-PCR, and their protein levels were detected by immunocytochemistry. The PKB and phospho- PKB protein levels were detected by Western blot and the apoptosis ratio was detected by flow cytometry. Resuits 2 × 10^-5mol·L^-1 LY294002 enhanced the sensitivities of SGC7901 and SGC7901/VCR cells to VCR（ P 〈 0. 01 ） significantly, their corresponding IC50 decreased from （0.20 ± 0. 03 ） and （ 8.09 ± 0. 6） mg·L^-1 to （0.05 ±0. 006 ） and （ 1.70± 0. 2） mg·L^-1 respectively; the mRNA and protein levels of MDR1 and XIAP were reduced by LY294002 obviously. There was obvious reduction in phospho-PKB levels following exposure to LY294002, but it had no effect on PKB levels in either cell line. When treated by LY294002 combined with VCR,the apoptosis ratios of both SGC7901 and SGC7901/VCR cells were much higher than those of VCR alone （ P 〈 0. 01 ）. Conclusion LY294002 could improve the chemotherapeutic sensitivities of human gastric carcinoma cell lines by reducing MDR1 and XIAP expression levels, which might be related to the inhibition of PI3K/PKB signal pathway.
出处
《中国药理学通报》
CAS
CSCD
北大核心
2008年第12期1666-1670,共5页
Chinese Pharmacological Bulletin
