%0 Journal Article %A JIARUI WANG %A HUILING WANG %A LONG ZHAO %A SUFANG FAN %A ZHONGHAI YANG %A FEI GAO %A LIXIA CHEN %A GARY GUISHAN XIAO %A JOSEPH MOLNÁR %A QI WANG %T Down-regulation of P-Glycoprotein Is Associated with Resistance to Cisplatin and VP-16 in Human Lung Cancer Cell Lines %D 2010 %J Anticancer Research %P 3593-3598 %V 30 %N 9 %X Aim: To investigate whether down-regulation of P-glycoprotein (P-gp) is correlated to resistance to cisplatin and VP-16 in four histopathological subtype cell lines of lung cancer (SK-MES-1, SPCA-1, NCI-H-460 and NCI-H-446). Materials and Methods: After pretreatment with or without verapamil, the P-gp expression was examined by means of RT-PCR and immunofluorescence. Cell survival on treatment with cisplatin and VP-16 was determined by MTT assay. Results: The expression of P-gp was clearly inhibited by verapamil in all four cell lines. Following pretreatment with verapamil, NCI-H-446 was more sensitive to cisplatin, while SPCA-1, NCI-H-460 and NCI-H-446 were more sensitive to VP-16 compared to the control. Conclusion: Down-regulation of P-gp is associated with intrinsic resistance to cisplatin in the NCI-H-446 and to VP-16 in SPCA-1, NCI-H-460 and NCI-H-446 cell lines. These findings indicate that down-regulation of P-gp may be helpful for the reversion of drug resistance in some lung cancer cell line subtypes. %U https://ar.iiarjournals.org/content/anticanres/30/9/3593.full.pdf