Interphase cell death as related to the cell cycle of melphalan-treated human myeloma cells

The effect of melphalan on cell loss, cell growth and cell-cycle traverse was studied on the human myeloma cell line RPMI 8226. Melphalan treatment resulted in arrest of cells in late S- and G2-phases in a population of unsynchronized cells. At high concentrations of melphalan (e.g. 40 microM), cell loss was noticed during the first cell cycle after melphalan treatment in addition to the aforementioned arrest of cells in late S and G2. The cell loss after melphalan treatment was further analysed in cells enriched for G1-phase. Cell death in this population of cells occurred between 24 and 48 hr after treatment as the cells were in S and moving over to G2.