5 304

Cited 9 times in

Hrk Mediates 2-Methoxyestradiol–Induced Mitochondrial Apoptotic Signaling in Prostate Cancer Cells

 Inik Chang  ;  Shahana Majid  ;  Sharanjot Saini  ;  Mohd S. Zaman  ;  Soichiro Yamamura  ;  Takeshi Chiyomaru  ;  Varahram Shahryari  ;  Shinichiro Fukuhara  ;  Guoren Deng  ;  Rajvir Dahiya  ;  Yuichiro Tanaka 
 MOLECULAR CANCER THERAPEUTICS, Vol.12(6) : 1049-1059, 2013 
Journal Title
Issue Date
Prostate cancer is one of the most prevalent cancers in males and ranks as the second most common cause of cancer-related deaths. 2-methoxyestradiol (2-ME), an endogenous estrogen metabolite, is a promising anticancer agent for various types of cancers. Although 2-ME has been shown to activate c-Jun-NH2-kinase (JNK) and mitochondrial-dependent apoptotic signaling pathways, the underlying mechanisms, including downstream effectors, remain unclear. Here, we report that the human Bcl-2 homology 3 (BH3)-only protein harakiri (Hrk) is a critical effector of 2-ME-induced JNK/mitochondria-dependent apoptosis in prostate cancer cells. Hrk mRNA and protein are preferentially upregulated by 2-ME, and Hrk induction is dependent on the JNK activation of c-Jun. Hrk knockdown prevents 2-ME-mediated apoptosis by attenuating the decrease in mitochondrial membrane potential, subsequent cytochrome c (cyt c) release, and caspase activation. Involvement of the proapoptotic protein Bak in this process suggested the possible interaction between Hrk and Bak. Thus, Hrk activation by 2-ME or its overexpression displaced Bak from the complex with antiapoptotic protein Bcl-xL, whereas deletion of the Hrk BH3 domain abolished its interaction with Bcl-xL, reducing the proapoptotic function of Hrk. Finally, Hrk is also involved in the 2-ME-mediated reduction of X-linked inhibitor of apoptosis through Bak activation in prostate cancer cells. Together, our findings suggest that induction of the BH3-only protein Hrk is a critical step in 2-ME activation of the JNK-induced apoptotic pathway, targeting mitochondria by liberating proapoptotic protein Bak.
Full Text
Appears in Collections:
2. College of Dentistry (치과대학) > Dept. of Oral Biology (구강생물학교실) > 1. Journal Papers
Yonsei Authors
Chang, In Ik(장인익)
사서에게 알리기


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.