The inductive effect of boric acid on growth inhibition and differentiating changes of human chronic myeloid leukemia K562 cell line

Recently, reports have been made of the effects of boric acid (BA) on cancer prevention and inhibition of cancer cell proliferation. This study was designed to investigate the effects of this compound on K562 cell line as a model of chronic myeloid leukemia (CML). In this experimental trial, K562 cell line was cultured in the presence of 0.75 to 12 mmol concentrations of boric acid for 24, 48, 72, and 96 hour intervals. Anti-proliferative and cytotoxic effects of BA were measured by trypan blue exclusion test and MTT assay, respectively. Flow-cytometery was utilized for evaluating the effects of BA on cell cycle. Wright-giemsa staining was used for determining the effects of BA, and latex phagocytic assay was used for evaluating the phagocytic potential of the differentiated cells. BA induced growth inhibition of K562 cells in a dose and time dependent manner; after 96 hours of treatment with 12 mmol BA, cell proliferation of K562 cells was inhibited to about 83% (p<0.001). In addition, BA induced G1 cell cycle arrest in a way that for instance, after 6 days of treatment with 9 mmol BA, 98% of cell populations were at G1 level. Wright-giemsa staining and latex phagocytic assay results confirmed that K562 cells differentiated toward monocyte-macrophage lineage. Noticing the anti-proliferative and differentiating effects of BA, and no evidence of its adverse effects, this compound can be used as alone or in combination with other drugs in CML differentiation therapy.