OBJECTIVETo investigate the in vitro effects of fludarabine on apoptosis and gene expression profile in human multiple myeloma (MM) cells.

METHODSCell growth was measured by a MTT assay. Cells apoptosis was evaluated by flow cytometry. The activation of caspase cascade was determined by Western blot analysis. The expression profile of apoptosis-related genes in human MM cells was detected by cDNA expression array system.

RESULTSThe growth of RPMI8226 and KM3 cells was suppressed by fludarabine treatment in a dose and time-dependent manner. After treatment with fludarabine for 24 h, the IC(50) for RPMI8226 cells was 2.13 µg/ml, and 0.36 µg/ml for KM3 cells. Apoptotic cells of RPMI8226 and KM3 increased in a dose- dependent manner after exposure to fludarabine for 24 h. Western blot analysis showed the activation of caspase-3 and PARP in the MM cells treated with fludarabine. The cDNA expression array showed that multiple pathways were involved in the apoptosis induced by fludarabine. Among 97 apoptosis-related genes, 25 genes were differently expressed and 13 expressions were up-regulated in fludarabine treated group, involving in Bcl-2 pro-apoptotic gene, tumor necrosis factor (TNF) and its receptor superfamily gene, and caspase recruitment domain family, 12 genes expression down-regulated, including Bcl-2 antiapoptotic gene, TNF superfamily and its receptor related factor gene and apoptosis inhibitor protein family.

CONCLUSIONFludarabine can significantly inhibit MM cell growth and induce apoptosis in vitro. The multiple pathways may be involved for the apoptosis in MM cells.