Prostate cancer (PCa) cells are dependent on androgen receptor (AR) function for growth and survival;this dependence is exploited in treatment of disseminated cancers, wherein ablation of AR activity is the first line of therapeutic intervention. While initially effective, recurrent tumors ultimately arise as a result of inappropriately restored AR function. AR is a master regulator of G1-S phase transitions in PCa, and interrogation of this mechanism led to the discovery of significant cross-talk mechanisms between the AR and cell cycle pathways. Cyclin D1 is a major effector of androgen action, and serves specialized functions in PCa that were delineated during the first funding period. Active AR induces cyclin D1 accumulation, thereby stimulating cyclin dependent kinase 4 (CDK4) activity and G1 progression. However, we and others showed that accumulated cyclin D1 binds and inhibits AR activity, thereby engaging a negative feedback loop to attenuate subsequent mitogenic response in AR-positive PCa cells. These actions of cyclin D1 contribute to the observed cell cycle dependence of AR activity in PCa, wherein AR activity is inversely correlated with cyclin D1 expression. Thus, cyclin D1 serves as a """"""""rheostat"""""""" that controls the strength and duration of the androgen response. The achieved goals of the first funding period were to dissect the mechanism and regulation of this cross-talk pathway in PCa. Our published and unpublished data demonstrate that cyclin D1 is a major effector of AR activity, and acts through defined mechanisms to alter both AR activity and androgen-dependent proliferation in PCa. Moreover, we demonstrated that aberrations in this process facilitate unleashed AR activity. Thus, this renewal application is based on the hypothesis that abrogation of cyclin D1 transcriptional regulatory function promotes unchecked AR activity in PCa cells, and provides a mechanism to promote tumor development and/or progression. The present renewal application will directly challenge this concept by dissecting the molecular impact of cyclin D1 action (and aberrations thereof) under conditions associated with tumor progression (aim 1), defining the consequence of cyclin D1b, a splice variant of cyclin D1 that is deficient in AR control and is induced in PCa, on androgen mediated gene regulation (aim 2), and determining the oncogenic capacity of cyclin D1b in the prostate (aim 3).

Public Health Relevance

Fatal prostate cancer arises as a result of inappropriate androgen receptor (AR) activity, a protein that controls the action of testosterone. We discovered that aberrations in a second gene product (cyclin D1) serve to promote unchecked AR activity and tumor growth. Here, we will determine molecular mechanisms through which cyclin D1 controls AR and determine the importance of this protein in prostate cancer, with the long term goal of devising new therapies to treat this deadly disease.

National Institute of Health (NIH)
National Cancer Institute (NCI)
Research Project (R01)
Project #
Application #
Study Section
Molecular and Cellular Endocrinology Study Section (MCE)
Program Officer
Woodhouse, Elizabeth
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Thomas Jefferson University
Schools of Medicine
United States
Zip Code
Thangavel, Chellappagounder; Boopathi, Ettickan; Liu, Yi et al. (2018) Therapeutic Challenge with a CDK 4/6 Inhibitor Induces an RB-Dependent SMAC-Mediated Apoptotic Response in Non-Small Cell Lung Cancer. Clin Cancer Res 24:1402-1414
Centenera, Margaret M; Hickey, Theresa E; Jindal, Shalini et al. (2018) A patient-derived explant (PDE) model of hormone-dependent cancer. Mol Oncol 12:1608-1622
Thangavel, Chellappagounder; Boopathi, Ettickan; Liu, Yi et al. (2017) RB Loss Promotes Prostate Cancer Metastasis. Cancer Res 77:982-995
Thomas, Jeffrey D; Longen, Charles G; Oyer, Halley M et al. (2017) Sigma1 Targeting to Suppress Aberrant Androgen Receptor Signaling in Prostate Cancer. Cancer Res 77:2439-2452
Londin, Eric; Loher, Phillipe; Telonis, Aristeidis G et al. (2015) Analysis of 13 cell types reveals evidence for the expression of numerous novel primate- and tissue-specific microRNAs. Proc Natl Acad Sci U S A 112:E1106-15
de Leeuw, Renée; Berman-Booty, Lisa D; Schiewer, Matthew J et al. (2015) Novel actions of next-generation taxanes benefit advanced stages of prostate cancer. Clin Cancer Res 21:795-807
Feng, Felix Y; de Bono, Johann S; Rubin, Mark A et al. (2015) Chromatin to Clinic: The Molecular Rationale for PARP1 Inhibitor Function. Mol Cell 58:925-34
Augello, Michael A; Berman-Booty, Lisa D; Carr 3rd, Richard et al. (2015) Consequence of the tumor-associated conversion to cyclin D1b. EMBO Mol Med 7:628-47
Dressing, Gwen E; Knutson, Todd P; Schiewer, Matthew J et al. (2014) Progesterone receptor-cyclin D1 complexes induce cell cycle-dependent transcriptional programs in breast cancer cells. Mol Endocrinol 28:442-57
Schrecengost, Randy S; Dean, Jeffry L; Goodwin, Jonathan F et al. (2014) USP22 regulates oncogenic signaling pathways to drive lethal cancer progression. Cancer Res 74:272-86

Showing the most recent 10 out of 59 publications