Broad antiproliferative effects of benidipine on cultured human mesangial cells in cell cycle phases

Background and purpose: Recently, in vitro studies have shown that some Calcium Channel blockers inhibit the proliferation of mesangial cells. In the present study, we evaluated the antiproliferative effects of benidipine, a Calcium Channel blocker, in comparison with other Calcium Channel blockers, and attempted to further clarify its mechanism of action on cultured human mesangial cells in relation to cell cycle.

Methods: Human mesangial cells were cultured in medium containing 5% fetal calf serum (FCS), with or without benidipine, or other Calcium Channel blockers for 20 h, and [(3)H]thymidine incorporation were measured. Analysis of cell cycle dependency was carried out, using platelet-derived growth factor as a competence factor, which transfers cells from the G0 to the G1 (G0/G1) phase, and Insulin as a progression factor, which transfers cells from the G1 to the S (G1/S) phase. Cells were also analyzed by flow cytometry.

Results: Benidipine and nifedipine showed significant inhibitory effects on FCS-induced proliferation (p < 0.001 and p < 0.01, respectively, by ANOVA), with 3.8 and 41.9% of the control level of [(3)H]thymidine incorporation at the concentration of 10 microM of the blockers, respectively. Diltiazem had no inhibitory effect at this concentration. Benidipine was found to inhibit cells in both the boundaries of G0/G1 and G1/S phases (p < 0.001 and p < 0.0001, respectively), whereas nifedipine inhibited only cells in G1/S phase (p < 0.05). The effects of benidipine (10 microM) on cells in G1/S were stronger than those on cells in the G0/G1 phase (p < 0.0001). Furthermore, flow cytometry showed that 10 mM benidipine significantly inhibited the G1 to S phase transition of FCS-stimulated mesangial cells (p < 0.03).

Conclusions: Benidipine markedly inhibited the proliferation of mesangial cells, at both the G0/G1 and G1/S phases, and it might be effective to suppress the progression of mesangioproliferative glomerular diseases.