OBJECTIVESTo examine the effects of suramin on the growth, cell cycle and apoptosis of a hormone refractory prostate cancer cell line PC-3M, and to explore the possible mechanisms.

METHODSThe roles of diverse concentrations (10, 50, 100 and 200 mumol/L) of suramin on PC-3M cell proliferation at different ratios of fetal calf serum (FCS) (2%, 5%, 10%) were assayed respectively by trypan blue exclusion and tetrazolium (MTT) assay. The effect of suramin on cell cycle distribution and apoptosis induction of PC-3M cells was evaluated with flow cytometry (FCM).

RESULTSA higher dosage of suramin (200 mumol/L) had a cytotoxic effect on PC-3M cells, while lower dosages from 10 to 100 mumol/L produced a predominant inhibiting effect. Suramin could also play a growth suppressive role in the culture media containing 10% FCS, but to a much less extent than in the media containing lower concentrations(5%, 2%) of FCS. FCM analysis exhibited that suramin at a high dosage of 200 mumol/L could induce apoptosis, and at the other concentrations, G0/G1 cell cycle arrest.

CONCLUSIONSuramin's proliferative suppression on PC-3M cells might result from several mechanisms including antagonistic action on growth stimulation via growth factor, arrest of cell cycle and induction of apoptosis.