Expression data from human cell lines before and after treated with drugs.

Analysis of HER2-amplified NCI-N87 gastric cancer cell line exposed to 0.1 µg/mL T-DM1 and subsequently cultured in the presence of gradually increasing doses, up to a maximum of 4 µg/mL. The resultant cell lines that grew exponentially in the presence of T-DM1 were designated as drug resistant gastric cancer cell lines, and named N87-TDMR. We used microarrays to detail the gene expression in N87-TDMR and N87-parent cells to screen for transcripts correlated with T-DM1 resistance. Total RNA was purified using RNeasy Mini Kit (Qiagen), including a DNase digestion treatment. RNA concentrations were determined by NanoDrop 2000 (Thermo Scientific). RNA was labeled using the GeneChip® WT Terminal Labeling and Controls Kit combined with the Ambion® WT Expression Kit. Labeled cRNA was hybridized to GeneChip® Human Transcriptome Array 2.0 arrays (Affymetrix).