Abstract:

Objective To investigate the effects of curcumin on the proliferation and differentiation of HL-60 early immature leukemia cells as well as on their expression of silk protein（cofilin）. Methods HL-60 cells were treated for 24 h with curcumin （6.25，12.5，and 25 μmol/L） or not （control）. Then cultures were examined using the MTT assay to detect effects of curcumin on proliferation，inverted microscopy to detect changes in cell morphology，flow cytometry to detect alterations in the cell cycle，and two-dimensional electrophoresis and mass spectrometry to detect cofilin protein expression. Results The apoptotic rate of HL-60 cells increased with increasing curcumin concentration at 24 h，the rate in each concentration group were as follows：（6.46±0.73）%，6.25 μmol/L；（9.79±1.36）%，12.5 μmol/L；and（79.48±7.99）%，25 μmol/L，（P<0.05）；they were higher with higher curcumin concentration（P<0.05）.Inverted microscopy showed morphological changes typical for cell growth arrest. Flow cytometry showed that curcumin at 12.5 μmol/L arrested cells at the G2/M transition of the cell cycle. Two-dimensional electrophoresis and mass spectrometry analysis showed that curcumin down-regulated cofilin expression in HL-60 cells. Conclusion These in vitro studies suggest that curcumin can inhibit the proliferation of HL-60 promyelocytic leukemia cells in a concentration-dependent manner. Sufficiently high concentrations can arrest the cell cycle and block differentiation. At least some of these curcumin effects may occur via down-regulation of intracellular cofilin expression.

Key words: Leukemia, Curcumin, Acute promyelocytic leukemia cells, Cofilin