Researchers have known for decades that signaling events in the cytoplasm can have profound effects on signaling events in the nucleus; however details regarding how this cytoplasm to nuclear (outside-inside) cross talk is regulated are stil not known. We have recently discovered that paxillin, a molecule best known for regulating cytoskeletal remodeling, is a critical liaison between extranuclear and intranuclear signaling in prostate cancer cells. Specifically, we find that paxillin is necessary for extranuclear Erk activation in response to multiple inputs, including nongenomic androgen signaling via membrane-localized androgen receptors (ARs) as well as growth factors via Receptor Tyrosine Kinases (RTKs). Once activated, Erk then regulates phosphorylation of paxillin on serine residues, at which point phosphoserine-paxillin travels to the nucleus and mediates AR- and Erk-dependent transcription. In fact, if we prevent this Erk-mediated phosphorylation of paxillin, then paxillin will not enter the nucleus, androgen and growth factor-dependent transcription is abrogated, and prostate cancer cells do not proliferate in response to any of these agonists. Importantly, we find that cytoplasmic paxillin and nuclear phosphoserine-paxillin expression are upregulated in human prostate cancer relative to normal prostate tissue, implying that paxillin is over-active in tumors. Together, our data suggest that paxillin might be a key mediator of prostate cancer growth and therefore a viable diagnostic and therapeutic target. Furthermore, since paxillin actually regulates Erk activation and downstream effects in every tumor cell line tested, regardless of origin, we postulate that paxillin might be a general regulator of Erk action well beyond the prostate. In this proposal, we will continue to focus on prostate cancer models to further elucidate how paxillin regulates outside-inside signaling in response to growth factors, androgens, and other steroids. In addition, we will examine paxillin effects on prostate cancer growth in-vivo, and will more closely examine paxillin expression and activation in human prostate cancer. Finally, we will test novel means of specifically regulating paxillin's actions in the nucleus while sparing it's actions in the cytoplasm, thereby using nuclear paxillin as a target for the treatment of both castration-sensitive and castration-resistant prostate cancer growth.

Public Health Relevance

Prostate cancer growth is regulated by androgens and growth factors. All of these factors stimulate kinase signaling that originates at the plasma membrane. These kinase signals then transmit information to the nucleus, where changes in gene expression drive cancer cells to proliferate. We propose to study how these signals outside the nucleus are able to mediate events inside the nucleus, focusing on a novel protein called paxillin.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM101709-03
Application #
8786088
Study Section
Molecular and Cellular Endocrinology Study Section (MCE)
Program Officer
Gaillard, Shawn R
Project Start
2013-01-01
Project End
2016-12-31
Budget Start
2015-01-01
Budget End
2015-12-31
Support Year
3
Fiscal Year
2015
Total Cost
$262,485
Indirect Cost
$91,485
Name
University of Rochester
Department
Internal Medicine/Medicine
Type
Schools of Dentistry
DUNS #
041294109
City
Rochester
State
NY
Country
United States
Zip Code
14627
Ma, Xiaoting; Hammes, Stephen R (2018) Paxillin actions in the nucleus. Steroids 133:87-92
Lerman, Irina; Hammes, Stephen R (2018) Neutrophil elastase in the tumor microenvironment. Steroids 133:96-101
Ma, Xiaoting; Hayes, Emily; Biswas, Anindita et al. (2017) Androgens Regulate Ovarian Gene Expression Through Modulation of Ezh2 Expression and Activity. Endocrinology 158:2944-2954
Lerman, Irina; Garcia-Hernandez, Maria de la Luz; Rangel-Moreno, Javier et al. (2017) Infiltrating Myeloid Cells Exert Protumorigenic Actions via Neutrophil Elastase. Mol Cancer Res 15:1138-1152
Miedlich, Susanne U; Taya, Manisha; Young, Melissa Rasar et al. (2017) Paxillin and embryonic PolyAdenylation Binding Protein (ePABP) engage to regulate androgen-dependent Xenopus laevis oocyte maturation - A model of kinase-dependent regulation of protein expression. Mol Cell Endocrinol 448:87-97
Levin, Ellis R; Hammes, Stephen R (2016) Nuclear receptors outside the nucleus: extranuclear signalling by steroid receptors. Nat Rev Mol Cell Biol 17:783-797
Ma, Xiaoting; Hayes, Emily; Prizant, Hen et al. (2016) Leptin-Induced CART (Cocaine- and Amphetamine-Regulated Transcript) Is a Novel Intraovarian Mediator of Obesity-Related Infertility in Females. Endocrinology 157:1248-57
Light, Allison; Hammes, Stephen R (2015) LH-Induced Steroidogenesis in the Mouse Ovary, but Not Testis, Requires Matrix Metalloproteinase 2- and 9-Mediated Cleavage of Upregulated EGF Receptor Ligands. Biol Reprod 93:65
Hammes, Stephen R; Davis, Paul J (2015) Overlapping nongenomic and genomic actions of thyroid hormone and steroids. Best Pract Res Clin Endocrinol Metab 29:581-93
Kamal, Fadia A; Mickelsen, Deanne M; Wegman, Katherine M et al. (2014) Simultaneous adrenal and cardiac g-protein-coupled receptor-g?? inhibition halts heart failure progression. J Am Coll Cardiol 63:2549-2557

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