The possible separation of 12-O-tetradecanoylphorbol-13-acetate-induced skin inflammation and hyperplasia by compound A.

Abstract

Activated glucocorticoid receptor (GR) acts via two different mechanisms: transcriptional regulation that requires DNA-binding, and protein-protein interaction between GR and other transcription factors, such as nuclear factor kappa B (NF-κB) or activator protein 1 (AP-1). It has been postulated that many important effects of glucocorticoids, including their anti-inflammatory properties, depend on GR's transrepressive effects on NF-κB and AP-1. In the present study, we have employed a TPA-induced model of skin inflammation and epidermal hyperplasia to determine whether partial activation of the glucocorticoid receptor by compound A (CpdA) is sufficient to reverse the effect of TPA treatment. CpdA is a nonsteroidal GR modulator with high binding affinity, is capable of partial activation of GR. Topical application of TPA twice per week for 2 wk results in inflammation and epidermal hyperplasia. TPA treatment also elevates levels of c-jun (AP-1 component), cyclooxygenase-2 (COX-2), p50 (NF-κB component), interleukin-6 (IL-6), and tumor necrosis factor (TNF) in the skin. Fluocinolone acetonide (FA) (a full GR agonist) was able to completely reverse the above effects of TPA. When applied alone, CpdA increased the epidermal thickness and keratinocyte proliferation as well as levels of c-jun, COX-2, IL-6, and IFN-γ. However, CpdA treatment resulted in a decrease in the number of p50 positive cells induced by TPA, suggesting its role in inhibition of NF-κB. The level of metallothionein-1 mRNA, regulated by GR was also significantly decreased in skin samples treated with CpdA. Our results suggest that CpdA is able to inhibit GR transactivation and activate only some transrepression properties of GR.

• Authors: Piotr Kowalczyk, Magdalena C Kowalczyk, Jacob J Junco, Olga Tolstykh, Tatsuya Kinjo, Ha Truong, Zbigniew Walaszek, Margaret Hanausek, Thomas J Slaga
• Journal: Molecular carcinogenesis (Mol Carcinog) Vol. 52 Issue 6 Pg. 488-96 (Jun 2013) ISSN: 1098-2744 [Electronic] United States
• PMID: 22351517 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)
• Copyright: Copyright © 2012 Wiley Periodicals, Inc.

Chemical References

• 2-(4-acetoxyphenyl)-2-chloro-N-methylethylamine
• Acetates
• Cytokines
• NF-kappa B
• Proto-Oncogene Proteins c-jun
• RNA, Messenger
• Receptors, Glucocorticoid
• Ptgs2 protein, mouse
• Cyclooxygenase 2
• Tetradecanoylphorbol Acetate
• Tyramine

Topics

• Acetates (pharmacology, therapeutic use)
• Animals
• Cyclooxygenase 2 (analysis, genetics)
• Cytokines (analysis, immunology)
• Drug Eruptions (drug therapy, genetics, immunology, pathology)
• Epidermis (drug effects, immunology, metabolism, pathology)
• Female
• Hyperplasia (chemically induced, drug therapy, genetics, pathology)
• Mice
• Mice, Inbred SENCAR
• NF-kappa B (analysis, genetics)
• Proto-Oncogene Proteins c-jun (analysis, genetics)
• RNA, Messenger (genetics)
• Receptors, Glucocorticoid (agonists, genetics, immunology)
• Skin (drug effects, immunology, metabolism, pathology)
• Tetradecanoylphorbol Acetate
• Transcriptional Activation (drug effects)
• Tyramine (analogs & derivatives, pharmacology, therapeutic use)