Nuclear Targeting of Cyclin-Dependent Kinase 2 Reveals Essential Roles of Cyclin-Dependent Kinase 2 Localization and Cyclin E in Vitamin D-Mediated Growth Inhibition
Year: 2010
Type: article
Abstract: 1,25-Dihydroxyvitamin D(3) (1,25-(OH)(2)D(3)), inhibits proliferation of a variety of cell types including adenocarcinoma of the prostate. We have previously shown that 1,25-(OH)(2)D(3) increases the stability of the cyclin-dependent kinase inhibitor p27(KIP1), decreases cyclin-dependent kinase 2 (CDK2) activity, and promotes G(1) phase accumulation in human prostate cancer cells. These effects correlate with cytoplasmic relocalization of CDK2. In this study, we investigated the role of CDK2 cytoplasmic relocalization in the antiproliferative effects of 1,25-(OH)(2)D(3). CDK2 was found to be necessary for prostate cancer cell proliferation. Although induced by 1,25-(OH)(2)D(3), the cyclin-dependent kinase inhibitor p27(KIP1) was dispensable for 1,25-(OH)(2)D(3)-mediated growth inhibition. Reduction in CDK2 activity by 1,25-(OH)(2)D(3) was associated with decreased T160 phosphorylation, a residue whose phosphorylation in the nucleus is essential for CDK2 activity. Ectopic expression of cyclin E was sufficient to overcome 1,25-(OH)(2)D(3)-mediated cytoplasmic mislocalization of CDK2 and all antiproliferative effects of 1,25-(OH)(2)D(3), yet endogenous levels of cyclin E or binding to CDK2 were not affected by 1,25-(OH)(2)D(3). Similarly, knockdown of the CDK2 substrate retinoblastoma, which causes cyclin E up-regulation, resulted in resistance to 1,25-(OH)(2)D(3)-mediated growth inhibition. Human prostate cancer cells resistant to growth inhibition by 1,25-(OH)(2)D(3) but retaining fully functional vitamin D receptors were developed. These cells did not exhibit 1,25-(OH)(2)D(3)-mediated cytoplasmic relocalization of CDK2. Targeting CDK2 to the nucleus of 1,25-(OH)(2)D(3)-sensitive cancer cells blocked G(1) accumulation and growth inhibition by 1,25-(OH)(2)D(3). These data establish central roles for CDK2 nuclear-cytoplasmic trafficking and cyclin E in the mechanism of 1,25-(OH)(2)D(3)-mediated growth inhibition in prostate cancer cells.
Source: Endocrinology
DOI: 10.1210/en.2009-1116
Authors: Omar Flores, Zhengying Wang, Karen E. Knudsen, Kerry L. Burnstein
Language: English
Topic: Vitamin D Research Studies
Subfield: Pathology and Forensic Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
Funders: U.S. Department of Veterans Affairs, University of Miami, Syracuse University, National Institutes of Health, Leonard M. Miller School of Medicine, Geriatric Research Education and Clinical Center, National Heart, Lung, and Blood Institute, National Cancer Institute, National Institute of Environmental Health Sciences
Awards: Training Program in Cardiovascular Signaling, Endocrine disruptors: AR regulation and prostate cancer, Targeting BRM as novel model of prostate hyperplasia, Cyclin D1: repercussions of AR control and alternative splicing in prostate cance, G6564429107, Vitamin D Promotes G1 Arrest via Cdk2 Mislocalization
OpenAlex ID: W2011528548