Expression data from human colonic cancer cell line SW480 and its acquired 17-AAG resistance cell line SW480-R

Heat shock protein 90 (HSP90) is a molecular chaperone required for the stability and function of many proteins. The chaperoning of oncoproteins by HSP90 enhances survival, growth and invasive potential of cancer cells. HSP90 inhibitors are promising new anticancer agents, in which the benzoquinone ansamycin 17-allylamino-17-demethoxygeldanamycin (17-AAG) is currently in clinical evaluation. However, the implications of acquired resistance to this class of drug remain largely unexplored. In the present study, we have generated isogenic human colonic cancer cell line SW480 that is resistant to 17-AAG by continued culturing in the compound. We used microarrays to detail the global programme of gene expression underlying the acquired resistance to 17-AAG in SW480 and SW480-R cell lines. SW480 cells were incubated and treated with 17-AAG at an initial concentration of 1×IC50. The medium with the compound was replaced every 48 h to discard dead cells. When surviving cells grow to 80% confluence, cells were passaged and the 17-AAG concentration was then added as follows: 2×, 4×, 6× ……IC50 till undulated. The generated resistant cell line(SW480-R) was cultured without 17-AAG at least of 2 weeks for RNA extraction and hybridization on Affymetrix microarrays, and for other analysis. Paired parental cells in another flask were serially passaged without 17-AAG as an untreated control.