Fig. 2
Metformin induces G0/G1 cell cycle arrest, but not apoptosis in myeloma cell lines. a, b Representative results showing the distribution of cells in G0/G1, S, or G2 phase in RPMI8226 and U266 cells following treatment or with metformin (5 mM or 20 mM) or without for 24 and 48 h. Histograms showing the percentage of myeloma cells in G0/G1, S, and G2 phases. c Western blot showing repression of the G1 phase-related cell cycle regulatory proteins cyclin D1 and activation of p21CIP1 and p27KIP1 . d Histograms showing the percentage of apoptotic RPMI8226 and U266 cells following treatment with metformin (0, 5, 20 mM) for 24 and 48 h, as detected by flow cytometry. All the experiments were performed in triplicated and repeated on at least three occasions. **P < 0.01 and ***P < 0.001 compared with the control group