建立吉非替尼耐药的人结肠癌细胞系HT29/ZD，并初步探讨其耐药机制。方法：采用逐步增加剂量法诱导人结肠癌细胞HT29形成耐药细胞HT29/ZD；MTT法检测吉非替尼对细胞的半数抑制浓度IC50，计算耐药指数（RI）；计数法描绘生长曲线，计算倍增时间TD；FCM检测细胞周期；MTT法检测HT29/ZD对氟尿嘧啶（fluorouracil，5Fu）、顺铂（cisplatin，DDP）、奥沙利铂（oxaliplatin，LOHP）、伊立替康（irinotecan，CPT11）的交叉耐药谱；免疫细胞化学方法检测细胞Pgp、IGF1Ra、PIGF1R的表达。结果： 建立了吉非替尼耐药的人结肠癌细胞系HT29/ZD，其耐药指数RI为26.67，HT29/ZD和HT29的TD分别为33.25 h和37.7 h。FCM显示HT29/ZD的S期、G2/M期比例增加，G0/G1期减少。交叉耐药实验显示，HT29/ZD对5Fu、DDP、LOHP敏感性增加，以LOHP敏感性增加最显著；对CPT11呈现一定程度的耐药。HT29和HT29/ZD均有Pgp表达，但无差异，（P>0.05）；HT29/ZD IGF1Ra表达明显低于HT29（P<0.01），而PIGF1R表达则明显增强(P<0.01)。结论：吉非替尼耐药细胞HT29/ZD不存在与传统化疗药物相似的多药耐药性；磷酸化IGF1R（PIGF1R）活性增强可能是HT29/ZD的耐药机制之一，Pgp与其耐药性无关。

To establish a gefitinibresistant human colon carcinoma HT29/ZD cell line and to preliminarily study its drug resistance mechanisms. Methods: Gefitinibresistant HT29/ZD was induced by stepwise selection after exposure to increasing doses of gefitinib. IC50were determined by MTT assay and the resistance index (RI) was calculated. Cell growth curves were plotted and the double times were calculated by cell counting assay. Distribution of cell cycles were detected by flow cytometry. Crossresistance profiles of HT29/ZD to 5Fu, DDP, LOHP, and CPT11 were tested by MTT assay. Expression levels of IGFRa, PIGFR and Pgp were determined by immunocytochemistry method. Results: A genfibinibresistant human colon carcinoma cell line HT29/ZD has been established successfully, with the RI being 2667. The doubling times of HT29/ZD and HT29 cells were 33.25 and 37.7 h, respectively. Flow cytometry demonstrated that HT29/ZD cells of phase S and G2M were increased, but those of G0/G1 phase were reduced. We also found that, compared to HT29 cells, HT29/ZD cells had an increased sensitivity to 5Fu, DDP （P>005）, and showed certain resistance to CPT11（P>0.05）, but had a significantly increased sensitivity to LOHP. Immunocytochemical analysis demonstrated that HT29 and HT29/ZD cells had a similar expression of Pgp （P>0.05）. HT29/ZD cells had a lower expression of IGF1Ra (P<0.01) than HI29 cells but a higher expression of phosphoIGF1R (P<001). Conclusion:HT29/ZD has no multidrug resistance like traditional anticancer drugs. PhosphoIGF1R of HT29/ZD has an increased activity, which might be one of the mechanisms for the acquired resistance of HT29/ZD. Pgp has no relationship with acquired resistance to gefitinib.

辽宁省自然科学基金项目(No.20022123)