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Title page for ETD etd-03172016-154256


Type of Document Dissertation
Author Austin, David C.
Author's Email Address davidmcaustin@gmail.com
URN etd-03172016-154256
Title The Role of Nuclear Factor Kappa B in Benign Prostatic Hyperplasia
Degree PhD
Department Cancer Biology
Advisory Committee
Advisor Name Title
Fiona Yull Committee Chair
Ann Richmond Committee Member
Deborah Lannigan Committee Member
Dineo Khabele Committee Member
Simon Hayward Committee Member
Keywords
  • Androgen Receptor Variant 7
  • Inflammation
  • Androgen Receptor
Date of Defense 2015-12-11
Availability restricted
Abstract
Benign prostatic hyperplasia (BPH) is a common, progressive chronic disease. Inflammation is associated with prostatic enlargement and resistance to 5?-reductase inhibitor (5ARI) therapy. Activation of the nuclear factor-kappa B (NF-?B) pathway is linked to both inflammation and ligand-independent prostate cancer progression. Most patients initially respond to 5ARI therapy; however, failure is common. To address why patients fail therapy we used transition zone tissue samples from patients with a wide range of American Urological Association symptom score (AUASS) from incidental BPH in patients treated for low grade, localized peripheral zone prostate cancer to advanced disease requiring surgical intervention. NF-?B activation and androgen receptor variant (AR-V) expression were quantified. To further investigate these pathways, human prostatic stromal and epithelial cell lines were transduced with constitutively active or kinase dead forms of IKK2 to regulate canonical NF-?B activity, AR-FL, and AR-variant 7 (AR-V7). We determined that canonical NF-?B signaling was found to be upregulated in late versus early stage BPH. Elevated expression of AR-V7 was found in advanced BPH samples. Expression of AR-V7 significantly correlated with the patient AUASS. Forced activation of canonical NF-?B in human prostatic epithelial and stromal cells resulted in elevated expression of both AR-FL and AR-V7, with concomitant ligand-independent activation of AR reporters. Activation of NF-?B and over expression of AR-V7 in human prostatic epithelial cells maintained cell viability in the face of 5ARI treatment. To understand why NF-?B and AR-V7 maintained viability within 5ARI treatment we examined the levels of 5?-reductase enzymes (SRD5A1, SRD5A2, SRD5A3). We determined that SRD5A2 is upregulated in more advanced BPH. SRD5A2 was significantly associated with AUASS and patients on a 5ARI. AR-FL and AR-V7 expression increased SRD5A2 expression whereas forced NF-?B activation increased all SRD5A isoforms. In summary, activation of NF-?B and AR-V7 in the prostate is associated with increased disease severity. Increased BPH severity in patients correlates with SRD5A2 expression. De novo synthesis of androgens and AR-V7 expression is inducible in human prostate cells by forced activation of NF-?B. NF-?B and AR-V7 upregulate SRD5A2 resulting in resistance to 5ARI treatment, suggesting a potential mechanism by which patients may become resistant to 5ARI therapy.

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