Establishment and characterization of a paclitaxel-resistant human non-small cell lung cancer cell line

We have established a paclitaxel-resistant mutant cell line called H460/TAX which was derived from human non-small cell lung cancer (NSCLC) H460. A 64-fold greater resistant was shown in our assay as compared with the parental cells. High specificity of drug resistance was also observed since this mutant was not cross-resistant to several other anticancer drugs. Drug accumulation in H460/TAX was significantly less than that in H460. Many endogenous protein profiles were intact, including the expression level of P-glycoprotein, multidrug resistance-associated protein, the 70 kDa heat shock proteins as well as the phosphorylation of Bcl-2 in H460/TAX cells, except that the total amount of alpha- and beta- tubulins was higher in H460/TAX than in H460 cells. Higher drug concentration and longer treatment for paclitaxel were required in H460/TAX to exert the phosphorylation of keratin 19 which was then accompanied by reorganization of the intermediate filament and the microtubule networks. Since all of the aforementioned factors involved in paclitaxel-resistance in other systems were not found to be significantly altered in H460/TAX, there must be other paclitaxel-resistance mechanisms(s) which remains to be identified in human lung cancers.