Voltage-dependent Kv1.3 potassium channels in the plasma membrane of acute lymphoblastic leukemic B-cells are non-conductive.

Kv1.3 is unique functional voltage-dependent K+ channel in normal and leukemic human lymphocytes. Here, we show that cell lines and primary cells of acute lymphoblastic leukemia (B-ALL) express Kv1.3 protein at high levels and that it is located at the plasma membrane. Surprisingly, and in contrast to healthy B cells, B-ALL cells lack Kv1.3 plasma membrane currents. However, B-ALL cell lines and primary B-ALL patient samples displayed a robust Ca2+-dependent KCa3.1 current, comparable to that in activated B cells. The importance of the present finding for further development of antileukemic chemotherapeutic strategies is that the lack of one of the two principal lymphocyte K+ currents, which are partly redundant in their function, could render B-ALL cells more vulnerable to treatments targeting the remaining KCa3.1 current.