Effects of propranolol and timolol on proliferation and apoptosis of hemangioma stem cells

Objective To investigate the effects of beta-blocker, propranolol and timolol on the proliferation and apoptosis of hemangioma stem cells (HemSCs). Methods Different concentrations(3, 30, 90, 150 μmol/L)of propranolol and timolol were added in HemSCs culture respectively for 24, 48 and 72 h, and cell proliferation and apoptosis were detected by flow cytometry. Experimental data were analyzed using SPSS 19.0 software. Statistically significance was determined using Student′s t test. Values of P<0.05 were considered statistically significant. Results Proliferation assay indicated that different concentrations of propranolol and timolol could inhibit HemSCs proliferation, and inhibition degree increased with increasing concentration. However, the effects of propranolol was slightly stronger than that of timolol at high concentrations (30, 90 and 150 μmol/L), but the opposite was observed at low concentration(3 μmol/L)(P<0.05). The results of apoptosis experiment showed that timolol had stronger effect than propranolol in promoting apoptosis at low concentrations (3 and 30 μmol/L), which was 13.7% and 1.1% higher, respectively. Conclusions Inhibiting HemSCs proliferation and promoting apoptosis may be one of the mechanisms of propranolol and timolol in treating infantile hemangioma.The specific effects of both varies with the concentration and time. Key words: Hemangioma stem cells; Proliferation; Apoptosis; Propranolol; Timolol