Activation of sterile20-like kinase 1 in proteasome inhibitor bortezomib-induced apoptosis in oncogenic K-ras-transformed cells. Export

@article{citeulike:835023, abstract = {Bortezomib (PS-341), a specific proteasome inhibitor, exhibits antitumor activity against a wide range of malignancies. However, the molecular mechanisms by which bortezomib causes apoptosis selectively in cancer cells still remain unclear. Ras signaling is involved in multiple cellular processes, including cell cycle progression, differentiation, and apoptosis, and can either promote or inhibit apoptosis depending on the type of apoptotic stimuli and the cell model. Here, we investigated the role of K-ras signaling in bortezomib-induced apoptosis. We found that K-ras-transformed cells were more susceptible to bortezomib-induced apoptosis than were nontransformed cells and that bortezomib-induced apoptosis was mainly caspase dependent in K-ras-transformed cells. We also found that mammalian sterile20-like kinase 1 (MST1) was activated by bortezomib in K-ras-transformed cells and K-ras-mutated cancer cells. Treatment of K-ras-transformed cells with bortezomib resulted in translocation of MST1 from cytoplasm into the nucleus and an increase of phosphorylated histone H2B and histone H2AX. Moreover, pretreatment with leptomycin B, an inhibitor of the nuclear export signal receptor, dramatically enhanced bortezomib-mediated MST1 activation, phosphorylation of histones H2B and H2AX, and apoptosis induction in K-ras-transformed cells. Knockdown of MST1 expression by small interfering RNA diminished bortezomib-induced apoptosis or caspase-3 activation. Our data suggested that bortezomib may be useful for treatment of K-ras-mutated cancer cells, and MST1 is one of the mediators for bortezomib-induced apoptosis in K-ras-transformed cells.}, address = {Department of Thoracic, The University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, USA.}, author = {Teraishi, F. and Guo, W. and Zhang, L. and Dong, F. and Davis, J. J. and Sasazuki, T. and Shirasawa, S. and Liu, J. and Fang, B.}, citeulike-article-id = {835023}, citeulike-linkout-0 = {http://dx.doi.org/10.1158/0008-5472.CAN-06-0125}, citeulike-linkout-1 = {http://view.ncbi.nlm.nih.gov/pubmed/16778179}, citeulike-linkout-2 = {http://www.hubmed.org/display.cgi?uids=16778179}, day = {15}, doi = {10.1158/0008-5472.CAN-06-0125}, issn = {0008-5472}, journal = {Cancer Res}, keywords = {apoptosis, inhibitor, k-ras, proteasome}, month = {June}, number = {12}, pages = {6072--6079}, posted-at = {2006-09-08 07:53:08}, priority = {2}, title = {Activation of sterile20-like kinase 1 in proteasome inhibitor bortezomib-induced apoptosis in oncogenic K-ras-transformed cells.}, url = {http://dx.doi.org/10.1158/0008-5472.CAN-06-0125}, volume = {66}, year = {2006} }

TY - JOUR ID - citeulike:835023 L3 - citeulike-article-id:835023 N2 - Bortezomib (PS-341), a specific proteasome inhibitor, exhibits antitumor activity against a wide range of malignancies. However, the molecular mechanisms by which bortezomib causes apoptosis selectively in cancer cells still remain unclear. Ras signaling is involved in multiple cellular processes, including cell cycle progression, differentiation, and apoptosis, and can either promote or inhibit apoptosis depending on the type of apoptotic stimuli and the cell model. Here, we investigated the role of K-ras signaling in bortezomib-induced apoptosis. We found that K-ras-transformed cells were more susceptible to bortezomib-induced apoptosis than were nontransformed cells and that bortezomib-induced apoptosis was mainly caspase dependent in K-ras-transformed cells. We also found that mammalian sterile20-like kinase 1 (MST1) was activated by bortezomib in K-ras-transformed cells and K-ras-mutated cancer cells. Treatment of K-ras-transformed cells with bortezomib resulted in translocation of MST1 from cytoplasm into the nucleus and an increase of phosphorylated histone H2B and histone H2AX. Moreover, pretreatment with leptomycin B, an inhibitor of the nuclear export signal receptor, dramatically enhanced bortezomib-mediated MST1 activation, phosphorylation of histones H2B and H2AX, and apoptosis induction in K-ras-transformed cells. Knockdown of MST1 expression by small interfering RNA diminished bortezomib-induced apoptosis or caspase-3 activation. Our data suggested that bortezomib may be useful for treatment of K-ras-mutated cancer cells, and MST1 is one of the mediators for bortezomib-induced apoptosis in K-ras-transformed cells. IS - 12 JF - Cancer Res SN - 0008-5472 AD - Department of Thoracic, The University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, USA. EP - 6079 TI - Activation of sterile20-like kinase 1 in proteasome inhibitor bortezomib-induced apoptosis in oncogenic K-ras-transformed cells. VL - 66 SP - 6072 KW - apoptosis KW - inhibitor KW - k-ras KW - proteasome AU - Teraishi, F AU - Guo, W AU - Zhang, L AU - Dong, F AU - Davis, JJ AU - Sasazuki, T AU - Shirasawa, S AU - Liu, J AU - Fang, B PY - 2006/06/15/ UR - http://dx.doi.org/10.1158/0008-5472.CAN-06-0125 ER -