Drug resistance-related changes in gene expression profile in multiple myeloma

1) We identified the genes whose expression was up- and down-regulated by the adhesion to bone marrow stromal cells in human multiple myeloma cell line RPMI8226. 2) We identified the genes whose expression was up- and down-regulated by the PI3K inhibitor PF-04691502 in human multiple myeloma cell line RPMI8226. We isolated mRNA from the multiple myeloma cell line RPMI8226 under drug-resistant conditions, and subjected them to gene expression profiling using an Agilent GeneChip Array.