Expression and roles of Cl- channel ClC-5 in cell cycles of myeloid cells.

ClC-5 is a chloride channel known to be expressed in the kidney. We previously reported that ClC-5 mRNA was also strongly expressed in immature human myeloid cell line (HL-60), but weakly expressed in mature neutrophils. To clarify the underlying mechanisms, we examined the relationship between ClC-5 expression and cell cycle. Dimethyl sulfoxide treatment of HL-60 that causes differentiation with G0/G1 cell cycle arrest decreased the expression of ClC-5 mRNA. Cell sorting and synchronization experiments revealed that ClC-5 mRNA expression was high in S and G2/M phases and low in G0/G1 phase. ClC-5 antisense oligonucleotide suppressed proliferation of HL-60 cells with a decrease in ClC-5 protein expression, probably due to G2 arrest. These results suggest that cell cycle-dependent expression of ClC-5 has a role in cell cycle progression in myeloid cells.