Genome-wide expression analysis of evolution of multi-drug resistance in Ramos cells

Examine gene expression in several variants of a human Burkitt's lymphoma cell line that had been selected to grow in media containing increaseing concentrations of doxorubicin. The six cell lines were Ramos cells; Dox100, a derivative of the Ramos cells that grows in media plus 100nM doxorubicin; Dox250, a derivative of Dox100 that grows in 250nM doxorubicin; Dox500, a derivative of Dox250 cells that grows in 500nM doxorubicin; Dox750, a derivative of Dox500 cells that grows in 750nM doxorubicin; and Dox1000, a derivative of Dox750 cells that grows in 1000nM doxorubicin. The six cell lines were grown in RPMI media plus 10% fetal bovine serum. Doxorubin was added to the media of the drug resistant lines to a final concentration equal to the line's stated resistance, i.e., Dox100 grown in media containing 100nM doxorubicin, etc. Four technical replicates of each cell line were made by splitting a single 25mL culture into four new 25mL cultures and allowing that to grow to a cell density of 10^6 cells/mL. Cells were centrifuged and total RNA was generated from all cultures in parallel.