The influence of several anticancer agents on cell proliferation, differentiation and the cell cycle of murine erythroleukemia cells.

The influence of homoharringtonine, hydroxycamptothecin and lycobetaine on the cell cycle progression of murine erythroleukemia cells was studied by using flow microfluorometry (FMF) technique and centrifugal elutriation to obtain specific fractions of the cell cycle. FMF histogram analysis showed that homoharringtonine could strongly arrest cells in the G1 phase of the immediate cell cycle. This effect was more pronounced and persisted longer with G1 cells than with S or G2 cells. Hydroxycamptothecin mainly delayed the progression of S cells of the subsequent cell cycle (daughter cells). Lycobetaine caused a marked accumulation of G2 cells. These 3 compounds possess a relatively specific action on cell progression through the cell cycle. Homoharringtonine and hydroxycamptothecin can inhibit the cell proliferation of murine erythroleukemia cells (MELC) at low concentrations (ng/ml) whereas lycobetaine, cantharidin and oxalysine are less potent. Among them only hydroxycamptothecin had a weak activity to induce MELC differentiation. These results may provide some basic knowledge for designing new protocols of the combination treatment of neoplastic diseases.