Ultrasound Research Today is a free monthly online journal that collates and summarizes the latest research about Ultrasound, including details on screening, diagnosis, pregnancy, detection.

Activation of Bak in ultrasound-induced, JNK- and p38-independent apoptosis and its inhibition by Bcl-2.

Kinoshita M, Eguchi Y, Hynynen K

Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA. mkinosit@bwh.harvard.edu

The molecular mechanisms underlying ultrasound-induced apoptosis remain poorly understood. We have demonstrated that in Jurkat cells, the over-expression of the anti-apoptotic protein Bcl-2 inhibited ultrasound-induced apoptosis, but not necrosis. Inhibition of caspase activity also protected the cells from apoptosis, but not from necrosis, showing the involvement of different mechanisms in ultrasound-induced apoptosis and necrosis. Bak, a pro-apoptotic member of the Bcl-2 family proteins, was activated by ultrasound and its activation was completely inhibited by Bcl-2 over-expression, but not by caspase inhibition. Antioxidant N-acetyl cysteine did not protect the cells from ultrasound-induced apoptosis or necrosis, nor did the inhibition of either c-Jun N-terminal kinase or p38, key factors in the radical oxygen species (ROS)-mediated cell stress response, suggesting that ROS do not play a crucial role in ultrasound-induced apoptosis. Our results confirm that ultrasound induces apoptosis via a pathway that involves Bak, Bcl-2, and caspases, but not ROS.

Published 3 January 2007 in Biochem Biophys Res Commun, 353(2): 515-21.
Full-text of this article is available online (may require subscription).

© 2004-2008 Ultrasound Research Today. All Rights Reserved.