A variety of ion channels has been discovered in lymphocytes. RT-PCR and real-time PCR analysis revealed that ALL (acute lymphocytic leukemia) cell lines and human peripheral blood mononuclear cells mainly expressed TTX (tetrodotoxin)-sensitive voltage-gated sodium channels (VGSCs). Expression of VGSC protein was confirmed by western blots and Immunofluorescence. Whole-cell patch-clamp recordings showed that a sub-population (20%) of MOLT-4 cells expressed functional VGSCs, which were TTX-sensitive. Importantly, 2 mu M TTX decreased the invasion of Jurkat and MOLT-4 cells similar to 90%. These results indicate that the activity of VGSCs could represent a novel mechanism potentiating the invasive capacity of these cells. (C) 2015 Elsevier Inc. All rights reserved.