Targeting CYP17: established and novel approaches in prostate cancer.
ABSTRACT There is a growing body of evidence that although medical or surgical castration blocks the generation of gonadal testosterone in prostate cancer, androgens originating from other sources may continue to drive androgen receptor (AR) signaling. Recent studies have demonstrated high intratumoral levels of androgens and continued AR signaling in castration-resistant prostate cancer (CRPC), suggesting that androgens may also be synthesized de novo. Inhibiting the systemic biosynthesis of androgens in CRPC by targeting CYP17 may thus represent a rational therapeutic approach since this enzyme catalyses two key steroid reactions involving 17alpha-hydroxylase and C(17,20)-lyase in the androgen biosynthesis pathway. This review will discuss the rationale for and implications of targeting CYP17 in CRPC and focus on established and novel CYP17 inhibitors, including ketoconazole, abiraterone acetate, and VN/124-1, which are agents currently at different stages of development.
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ABSTRACT: Androgen-deprivation therapy is the mainstay of treatment for the management of advanced prostate carcinoma till transition to castration-resistant prostate carcinoma (CRPC). Recently, adrenal and intratumoral synthesis of androgens has been found to be the major cause for CRPC. Abiraterone acetate is an orally active, potent and selective inhibitor of 17 a hydroxylase and c 17, 20 lyase, which acts by decreasing the de novo production of androgens with no rise in steroids downstream. Multiple randomized trials have shown significant improvement of >50% decline in prostate-specific antigen (PSA) and time to PSA progression (TTPP) with abiraterone acetate 1000 mg per day in chemotherapy/ketoconazole treated and naive CRPC patients producing reversible and manageable adverse effects due to mineralocorticoid excess. This article reviews the available evidence on efficacy and safety of this drug in CRPC. Searches of Pubmed, Cochrane database, Medscape, Google and clinicaltrial.org were made for terms like CRPC and abiraterone.Journal of Postgraduate Medicine 07/2012; 58(3):203-6. DOI:10.4103/0022-3859.101400 · 0.97 Impact Factor
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ABSTRACT: The relationship between CYP17A1 genetic polymorphisms and coronary artery disease (CAD) remains unclear. The aim of the present study was to assess the association between CYP17A1 gene polymorphism and CAD in a Chinese Uygur population. A total of 493 people including 266 patients and 227 controls were selected for the present study. All CAD patients and controls were genotyped for the same five single nucleotide polymorphisms (SNPs) (rs4919686, rs1004467, rs4919687, rs10786712, and rs2486758) by a real-time PCR method. The rs4919686, rs1004467, and rs4919687 polymorphisms were found to be associated with CAD in genotypes, dominant model, recessive model, and allele frequency (rs4919686: all p<0.05, rs1004467: all p≤0.001, rs4919687: all p<0.001); the significant difference was retained (all p<0.05) after adjustment for the major confounding factors. The overall distribution of haplotypes established by SNP1-SNP4 (in total subjects and men) and SNP1-SNP4-SNP5 (in total subjects) were significantly different between the CAD patients and the control subjects (p=0.006, men: p=0.026, and p=0.030, respectively). Polymorphisms rs4919686, rs4919687 and rs1004467 were found to be associated with CAD in this Uygur population. © The Author(s) 2015.Journal of Renin-Angiotensin-Aldosterone System 01/2015; DOI:10.1177/1470320314565840 · 2.27 Impact Factor
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ABSTRACT: Treatment of castration-resistant prostate cancer remains an area of unmet medical need. Evidence suggests that this entity continues to be driven by androgens and androgen receptor (AR) signaling. Abiraterone acetate, a pregnenolone derivative, is an oral selective and irreversible inhibitor of the key steroidogenic enzyme CYP17. It possesses dual 17-α hydroxylase and C17,20-lyase blocking activity, the result of which is decreased gonadal and extra-gonadal androgen synthesis. Abiraterone was first approved by the US Food and Drug Administration (FDA) in 2011 following the demonstration of superior survival compared with placebo in the post-docetaxel population. Since that time, more evidence has been generated from preclinical studies and clinical trials which have considerably enhanced our understanding of this complex disease. In this paper, we review the development of abiraterone acetate, its pharmacological characteristics, and its effects on the androgen-AR signaling axis, along with the combined experience from clinical trials. We also discuss some of the ongoing trials using this agent, as well as potential mechanisms of abiraterone resistance, novel bio-marker development, and future directions using AR-directed therapies.07/2013; 2013(7):1-14. DOI:10.4137/CMU.S8337