Nonsteroidal anti-inflammatory drugs (NSAIDs) strongly inhibit tumorigenesis in experimental animal models, but toxicity from cyclooxygenase (COX) inhibition limits their use in humans for cancer chemoprevention. Previous studies have concluded that a COX-independent mechanism is responsible their antineoplastic activities, which suggests that it may be feasible to develop safer and more efficacious drugs by targeting such mechanisms. We have found that the tumor cell growth inhibitory and apoptosis inducing properties of certain NSAIDs such as sulindac sulfide (SS) are closely associated with inhibition of the cGMP-specific phosphodiesterase, PDE5. SS can selectively inhibit PDE5 to increase intracellular cGMP levels and activate protein kinase G to phosphorylate 2-catenin, thereby inducing its degradation to suppress the transcription of key apoptosis regulatory proteins such as survivin. Recently, we have shown that siRNA knockdown of PDE5 can selectively induce apoptosis of tumor cells as does SS. The proposed studies will focus on breast cancer chemoprevention since PDE5 appears to be the predominant cGMP degrading isozyme in breast tumor cells that is also expressed in adenocarcinomas from breast cancer patients. We hypothesize that PDE5 plays an important role in breast tumorigenesis that can be targeted to develop safe and efficacious drugs for breast cancer chemoprevention. In support of this hypothesis, we have synthesized a series of novel tadalafil derivatives that potently and selectively inhibit the growth and induce apoptosis of breast tumor cells. To further test this hypothesis, Aim 1 will determine the importance of PDE5 and cGMP signaling for the anticancer activity of novel tadalafil derivatives and will evaluate PDE5 expression in human breast tumors;
Aim 2 will synthesize and evaluate novel tadalafil derivatives for in vitro anticancer activity and will identify candidates with optimal pharmacological properties for in vivo efficacy testing;
and Aim 3 will evaluate chemopreventive efficacy and safety of an optimal tadalafil derivative and will confirm mechanism of action in vivo. The goals of these studies are to validate PDE5 as an anticancer target, determine its potential role in cancer, and identify a safe and effective tadalafil derivative for preclinical drug development.

Public Health Relevance

impact of breast cancer is substantial with nearly one-fourth of the 180,000 cases diagnosed each year in the US resulting in death and greater than a 40% death rate worldwide. Besides the human toll of the disease, the economic strain to manage the diagnosis and treatment of this most common form of cancer in women is enormous. An important classification of breast tumors is based on the presence or absence of the estrogen receptor (ER). While the majority of breast cancers are ER+, approximately 30% are ERnegative. Patients with ER- disease are not sensitive to estrogen receptor antagonists or aromatase inhibitors that are commonly used for the management of ER+ disease and have a poorer clinical outcome compared to women with ER+ disease. As such, there is an urgent medical need for chemopreventive drugs to manage ER- breast cancer. We propose studies to develop a novel molecular target and class of compounds for chemoprevention of ER- breast cancer and which may also have potential for therapy.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA155638-02
Application #
8531883
Study Section
Chemo/Dietary Prevention Study Section (CDP)
Program Officer
Perloff, Marjorie
Project Start
2012-08-16
Project End
2017-05-31
Budget Start
2013-08-01
Budget End
2014-05-31
Support Year
2
Fiscal Year
2013
Total Cost
$336,653
Indirect Cost
$83,412
Name
University of South Alabama
Department
Type
Schools of Medicine
DUNS #
172750234
City
Mobile
State
AL
Country
United States
Zip Code
36688
Keeton, Adam B; Salter, E Alan; Piazza, Gary A (2017) The RAS-Effector Interaction as a Drug Target. Cancer Res 77:221-226
Zhu, Bing; Lindsey, Ashley; Li, Nan et al. (2017) Phosphodiesterase 10A is overexpressed in lung tumor cells and inhibitors selectively suppress growth by blocking ?-catenin and MAPK signaling. Oncotarget 8:69264-69280
Piazza, Gary A (2017) Validation of PDE5 as a Chemoprevention Target. Cancer Prev Res (Phila) 10:373-376
Yi, Bin; Chang, Hong; Ma, Ruixia et al. (2016) Inhibition of breast cancer cell motility with a non-cyclooxygenase inhibitory derivative of sulindac by suppressing TGF?/miR-21 signaling. Oncotarget 7:7979-92
Lee, Kevin; Lindsey, Ashley S; Li, Nan et al. (2016) ?-catenin nuclear translocation in colorectal cancer cells is suppressed by PDE10A inhibition, cGMP elevation, and activation of PKG. Oncotarget 7:5353-65
Prasain, Jeevan K; Rajbhandari, Rajani; Keeton, Adam B et al. (2016) Metabolism and growth inhibitory activity of cranberry derived flavonoids in bladder cancer cells. Food Funct 7:4012-4019
Li, N; Lee, K; Xi, Y et al. (2015) Phosphodiesterase 10A: a novel target for selective inhibition of colon tumor cell growth and ?-catenin-dependent TCF transcriptional activity. Oncogene 34:1499-509
Li, Nan; Chen, Xi; Zhu, Bing et al. (2015) Suppression of ?-catenin/TCF transcriptional activity and colon tumor cell growth by dual inhibition of PDE5 and 10. Oncotarget 6:27403-15
Koneczny, Inga; Schulenburg, Axel; Hudec, Xenia et al. (2015) Autocrine fibroblast growth factor 18 signaling mediates Wnt-dependent stimulation of CD44-positive human colorectal adenoma cells. Mol Carcinog 54:789-799
Aboul-Fadl, Tarek; Al-Hamad, Suliman S; Lee, Kevin et al. (2014) Novel non-cyclooxygenase inhibitory derivatives of naproxen for colorectal cancer chemoprevention. Med Chem Res 23:4177-4188

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