Expression analysis in A431_wt vs A431_GR cells

A431 wild-type (wt) cancer cell line is sensitive to treatment with EGFR tyrosine kinase inhibitors (TKIs). By culturing it chronically under gefitinib, it eventually becomes resistant (A431_GR cell). We know of a few proteins involved in this mechanism of drug resistance, but a cDNA exprssion array would add information to other genes that might be involved in this resistance mechanism. We used microarrays to identify the differences in the global gene expression between A431_wt (wild-type) cells and A431_GR cells. Keywords: comparison of two cell lines Total RNA was isolated from parental (wild-type) and GR (gefitinib-resistant) A431 cells using TRIzol reagent (Invitrogen, Carlsbad, CA), followed by RNeasy Mini Kit column purification (Qiagen, Valencia, CA) including an in column DNAse clean-up using RNAse-free DNAse Set (Qiagen). Synthesis of cRNA target, its hybridization to Human Genome U133 Plus 2.0 microarrays and scanning of those arrays was performed using Affymetrix GeneChip products and reagents in accordance with the manufacturer’s recommendations at the Vanderbilt Microarray Shared Resource.