Differential gene expression profile between PC-14 cells treated with free cisplatin and cisplatin-incorporated polymeric micelles.

Cisplatin (CDDP)-incorporated polymeric micelles (CDDP/m) are a macromolecular carrier system possessing a time-modulated decaying property accompanied by sustained release of free drug. The gene expression profiles in nonsmall cell lung cancer PC-14 cells treated with free CDDP and CDDP/m were evaluated by a cDNA expression array for 807 genes. Although the total gene expression profile of the cells treated with CDDP/m approximated that of free CDDP in the hierarchical clustering analysis, a number of genes showed differential expression according to whether the cells had been treated with CDDP or CDDP/m. Ultimately, 50 genes with significant differential expression between cells treated with CDDP and CDDP/m were selected by principal component (PC) analysis and the unpaired t-test. The genes selected, including genes related to cell cycle regulation, apoptosis-related proteins, detoxification, and DNA repair enzymes, were considered to be related to CDDP-induced cytotoxicity. Interestingly, CDDP/m down-regulated the genes encoding integrins and matrix metalloproteinases (MMPs), which play an integral role in tumor invasion, metastasis, and angiogenesis, whereas free CDDP up-regulated them. The results suggest that use of the macromolecular carriers may yield additional therapeutic effects over free drug.