👤 Véronique Bellemare

The relationship between polymorphisms in the hydroxysteroid (17-beta) dehydrogenase (HSD17B) family of genes, which are involved in steroid hormone biotransformation, and the risk of prostate cancer (PCa) progression remains unexplored. Determine whether inherited variations in HSD17B genes are associated with PCa progression. We studied two independent Caucasian cohorts composed of 526 men with organ-confined PCa and 213 men with advanced disease who had a median follow-up of 7.4 yr and 7.8 yr after surgery, respectively. Patients with localised PCa were genotyped for 88 haplotype-tagging single nucleotide polymorphisms in HSD17B type 1 (HSD17B1), type 2 (HSD17B2), type 3 (HSD17B3), type 4 (HSD17B4), type 5 (HSD17B5), and type 12 (HSD17B12), and their prognostic significance on disease progression was assessed using Kaplan-Meier survival curves and Cox regression models. Positive findings were then investigated in advanced disease. After adjusting for known risk factors, 12 SNPs distributed across HSD17B2, HSD17B3, and HSD17B12 were significantly associated with risk of biochemical recurrence (BCR) in localised PCa (for variants in HSD17B2: hazard ratio [HR]: 1.92-2.93; p=0.025-0.004). In addition, four variants of HSD17B2 (rs1364287, rs2955162, rs1119933, rs9934209) were significantly associated with progression-free survival (HR: 2.96-4.69; p=0.004-0.00005) and overall survival in advanced disease (HR: 3.98-8.14; p=0.003-0.00002). Four variants of HSD17B3 and HSD17B12 were associated with a reduced risk of BCR (HR: 0.51-0.65; p=0.020-0.036) but not with progression in advanced disease. These results were generated mainly in Caucasians and should be studied in other ethnic groups. This study suggests a prominent role for common genetic variants in the HSD17B2 pathway in PCa progression. Show less

17β-Hydroxysteroid dehydrogenases (17β-HSDs) are enzymes issued from convergent evolution of activity from various ancestral genes having different functions. Type 12 17β-HSD (17β-HSD12) was described as a bifunctional enzyme, involved in the biosynthesis of estradiol (E2) and the elongation of very long chain fatty acid (VLCFA). It catalyzes selectively the transformation of estrone (E1) into estradiol (E2) in human and primates, whereas in the mouse and Caenorhabditis elegans the enzyme catalyzes the 17β-reduction of both androgens and estrogens. It is also able to catalyze the reduction of 3-keto-acylCoA into 3-hydroxy-acylCoA in the elongation cycle of VLCFA biosynthesis. To further understand the physiological role of 17β-HSD12, we performed targeted disruption of the Hsd17b12 gene by substituting exons 8 and 9 that contain the active site with a neomycin cassette. The data indicate that heterozygous (HSD17B12+/-) mice are viable with reduced levels of sex steroids, whereas homozygous (HSD17B12-/-) mice show embryonic lethality. The present data are in agreement with the bifunctional activities of 17β-HSD12 suggesting that the VLCFA elongation activity, having its origin in the yeast, is most probably responsible for embryonic lethality in HSD17B12-/-, whereas the more recently acquired 17β-HSD12 activity is responsible for reduced sex steroid levels in HSD17B12+/-. Show less

Estradiol (E2) is produced locally in adipose tissue and could play an important role in fat distribution and accumulation, especially in women. It is well recognized that aromatase is expressed in adipose tissue; however the identity of its estrogenic 17beta-hydroxysteroid dehydrogenase (17beta-HSD) partner is not identified. To gain a better knowledge about the enzyme responsible for the conversion of estrone into estradiol, we determined the activity and expression levels of known estrogenic 17beta-HSDs, namely types 1, 7 and 12 17beta-HSD in preadipocytes before and after differentiation into mature adipocytes using an adipogenic media. Estrogenic 17beta-HSD activity was assessed using [(14)C]-labelled estrone, while mRNA expression levels of types 1, 7 and 12 17beta-HSD were quantified using real-time PCR and protein expression levels of type 12 17beta-HSD was determined using immunoblot analysis. The data indicate that there is a low conversion of E1 into E2 in preadipocytes; however this activity is increased approximately 5-fold (p<0.0001) in differentiated adipocytes. The increased estrogenic 17beta-HSD activity is consistent with the increase in protein expression levels of 17beta-HSD12. Show less