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目的探讨整合素β1及其下游信号转导通路在非小细胞肺癌表皮生长因子受体酪氨酸激酶抑制剂(EGFR-TKI)吉非替尼获得性耐药中的作用。方法以人肺腺癌细胞株PC-9和吉非替尼耐药株PC-9/G作为研究对象,免疫印迹分析检测整合素β1、Akt、磷酸化Akt蛋白的表达;用MTT法检测吉非替尼和(或)磷脂酰肌醇3激酶(PI3K)抑制剂LY294002、细胞外调节蛋白激酶(ERK)抑制剂PD98059对细胞增殖的影响;用AnnexinⅤ/PI试剂盒和TUNEL试剂盒检测细胞凋亡。结果吉非替尼耐药株PC-9/G高表达整合素β1,RNA干扰抑制整合素β1表达能够抑制PC-9/G细胞的生长和促进凋亡。PC-9/G细胞中吉非替尼对Akt磷酸化的抑制作用弱于PC-9细胞,RNA干扰抑制整合素β1表达后Akt的磷酸化水平降低。ERK抑制剂PD98059不能恢复PC-9/G细胞对吉非替尼的敏感性,PI3K抑制剂LY294002能恢复PC-9/G细胞对吉非替尼的敏感性。结论整合素β1过表达可以通过PI3K途径激活下游信号分子,这可能是一种重要的EGFR-TKI耐药机制。
Objective To investigate the role of integrin β1 and its downstream signal transduction pathways in acquired resistance to gefitinib in patients with non-small cell lung cancer (EGFR-TKI) epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI). Methods The human lung adenocarcinoma cell line PC-9 and the gefitinib-resistant PC-9 / G cell line were used as research objects. The expression of integrin β1, Akt and phospho-Akt protein were detected by Western blotting. The effect of phenylephrine and phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 and ERK inhibitor PD98059 on cell proliferation were detected by flow cytometry. Cell apoptosis was detected by AnnexinⅤ / PI kit and TUNEL kit Death. Results The high expression of integrin β1 in the gefitinib-resistant PC-9 / G cells inhibited the growth of PC-9 / G cells and inhibited the apoptosis of PC-9 / G cells. The inhibitory effect of gefitinib on Akt phosphorylation in PC-9 / G cells was weaker than that in PC-9 cells. RNAi inhibited the phosphorylation of Akt after the inhibition of integrinβ1 expression. ERK inhibitor PD98059 can not restore the sensitivity of PC-9 / G cells to gefitinib, and PI3K inhibitor LY294002 can restore the sensitivity of PC-9 / G cells to gefitinib. Conclusion Integrin β1 overexpression can activate downstream signaling molecules through the PI3K pathway, which may be an important mechanism of EGFR-TKI resistance.