Arsenic Trioxide Inhibits Human T Cell-Lymphotropic Virus-1-Induced Syncytiums by Down-Regulating gp46

Abstract

Adult T-cell leukemia (ATL) is a severe chemotherapy-resistant malignancy associated with prolonged infection by the human T cell-lymphotropic virus 1 (HTLV-1). One approach to prevent the onset of ATL is to inhibit the growth/transmission of HTLV-1 infected cells using arsenic trioxide (As₂O₃). However, there are no reports on the transmission inhibitory effect of As₂O₃. In this study, we reveal that As₂O₃ exerts an inhibitory effect on syncytium formation between HTLV-1 infected MT-2 and HeLa cells. In addition, Western blot analysis revealed that the HTLV-1 derived envelope protein gp46 was down regulated by As₂O₃ treatment, suggesting that As₂O₃ may inhibit HTLV-1 virus transmission via down-regulation of gp46. These results suggest that As₂O₃ may be a promising drug to treat refractory HTLV-1-related diseases.