Effects of lanthanum chloride on growth and apoptosis of K562 leukemia cell lines

Objective To investigate the effects of rare earth compound (lanthanum chloride, LaCl3) on the growth and apoptosis of K562 cells. Methods To investigate the effects of LaCl3 on the growth of K562 cells by MTT assay, the apoptosis detected by flow cytometry and TUNEL method, the cell cycle of K562 cells treated with LaCl3, and analyzed by flow cytometry, to evaluate the hematopoietic ability of normal bone marrow cells treated by LaCl3 by counting the granulocyte-macrophage colonies. Results MTT assay showed that treatment with 0.1, 0.5, 1.0, 1.5 and 2.0 mmol/L LaCl3 for 24 h, 48 h and 72 h could inhibit the growth of K562 cells. Apoptosis could be detected on treatment with 0.1, 0.5, 1.0, 1.5 and 2.0 mmol/L LaCl3 for 48 h in K562 cells by light microscopy morphology examination, and flow cytometry analysis. 1.0mmol/L for 24 h, 48 h, 72 h and 96 h treatment with 1mmol/L LaCl3 could significantly induce K562 apoptosis by flow cytometry and TUNEL method. Treatment of 1 mmol/L LaCl3 could arrest the transitions of K562 cells from G0/G1 to S phase. The granulocyte-macrophage colony formation (CFU-GM) of normal bone marrow cells was not significantly inhibited in treatment with 0.05 and 1.0 mmol/L LaCl3, but slightly increased in 0.1 and 0.5 mmol/L. Treatment with higher concentrations (1.5 to 2.0 mmol/L LaCl3), the colony formation was significantly inhibited. Conclusion Our data demonstrate that LaCl3 (0.1 to 1.0 mmol/L) may inhibit K562 cell growth and induce them to apoptosis.