Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), a member of the tumor necrosis factor gene family, is considered as one of the most promising cancer therapeutic agents due to its ability to selectively induce tumor cell apoptosis. In this study, we investigated whether the Na +/H+ exchanger inhibitor, amiloride, promotes TRAIL-induced apoptotic death both in sensitive and resistant tumor cells, HeLa and LNCaP cells, respectively, and its underlying molecular mechanism. Amiloride enhanced TRAIL-induced apoptosis and activation of caspase-3 and -8 in both cells. This compound increased TRAIL-induced mitochondrial cytochrome c release and poly(ADP-ribose) polymerase cleavage. Moreover, amiloride-induced intracellular acidification, and inhibited the phosphorylated activation of the serine/threonine kinase Akt, which is known to promote cell survival, in both tumor cells. These data suggest that amiloride sensitizes both tumor cells to TRAIL-induced apoptosis by promoting Akt dephosphorylation and caspase-8 activation via the intracellular acidification and that Na+/H + exchanger inhibitors may play an important role in the anti-cancer activity of TRAIL, especially, in TRAIL-resistant tumors with highly active and expressed Akt.
|Number of pages||7|
|Journal||Biochemical and Biophysical Research Communications|
|Publication status||Published - 2005 Jan 28|
Bibliographical noteFunding Information:
This work was supported by Vascular System Research Center grant from Korea Science and Engineering Foundation. We thank Mrs. Elaine Por for helpful comments and critical reading of the manuscript.
All Science Journal Classification (ASJC) codes
- Molecular Biology
- Cell Biology