Ion channels in K562 cells. Relation with the CFTR and MDR proteins.

ASSEF Y.; DAMIANO AE.; ZOTTA, E.; IBARRA, C.; KOTSIAS BA.

Buenos Aires, Argentina

Congreso; XIV International Biophysics Congress; 2002

IUPAB - Sociedad Argentina de Biofisica

We used the cell line K562 obteined from a chronic myeloid leukemia for the study of ion channels with patch clamp and RT-PCR techniques. Our objetives were the assessment of the expression of integral proteins such as the CFTR (cystic fibrosis transmembrane regulator) and MDR (multidrug resistance), thier pattern of expression and to establish their function as ion channels. The amplified products showed two bands of 300 bp and 170 bp corresponding to CFTR and MDR1. In the inside out configuration, forskoline (20 μM), an activator of adenylate cyclase turns o ion channel actity with a linear current-voltage relationship and a conductance of 12 pS wich is not affected by replacement Na+ by NMDG. These channels present a lower permeability (P) for gluconate and fluorure (F-) than Cl-, with relative permeabilities Pgluconate/PCl and PF/PCl of 0.24 and 0.20 respectively. Glibenclamide (100 μM) added to the bath diminished the open probability. The presence of an anion channel with conductance similar to CFTR, with no rectification and blocked with glibenclamide suggest that one of the products obtained through RT-PCR may have a functional expression in K562 cells, with a pattern not complementary with MDR. (supported by Ministerio de Salud de Argentina).