The Molecular Genetics of Steroid 5α-Reductases

Russell, David W.; Berman, David M.; Bryant, James T.; Cala, Kristine M.; Davis, Dana; Landrum, Charles P.; Prihoda, James S.; Silver, Richard I.; Thigpen, Anice E.; Wigley, W. Christian

doi:10.1016/b978-0-12-571149-4.50018-0

Cited by 40 publications

(32 citation statements)

References 19 publications

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“…There are two known isoforms of the human 5α-reductase, namely type 1 (5αR1) and type 2 (5αR2) [24-26]. 5αR1, which is encoded by the SRD5A1 gene and is composed of 259 amino acids, has an optimum pH of 6–9, whereas 5αR2, encoded by the SRD5A2 gene, and composed of 254 amino acids, has an optimum pH of 5.5 [27]. 5αR1 has been detected in various androgen-independent organs, such as the liver and brain [28].…”

Section: Discussionmentioning

confidence: 99%

Activity and expression of progesterone metabolizing 5α-reductase, 20α-hydroxysteroid oxidoreductase and 3α(β)-hydroxysteroid oxidoreductases in tumorigenic (MCF-7, MDA-MB-231, T-47D) and nontumorigenic (MCF-10A) human breast cancer cells

Wiebe

Lewis

2003

BMC Cancer

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BackgroundRecent observations indicate that human tumorous breast tissue metabolizes progesterone differently than nontumorous breast tissue. Specifically, 5α-reduced metabolites (5α-pregnanes, shown to stimulate cell proliferation and detachment) are produced at a significantly higher rate in tumorous tissue, indicating increased 5α-reductase (5αR) activity. Conversely, the activities of 3α-hydroxysteroid oxidoreductase (3α-HSO) and 20α-HSO enzymes appeared to be higher in normal tissues. The elevated conversion to 5α-pregnanes occurred regardless of estrogen (ER) or progesterone (PR) receptor levels. To gain insight into these differences, the activities and expression of these progesterone converting enzymes were investigated in a nontumorigenic cell line, MCF-10A (ER- and PR-negative), and the three tumorigenic cell lines, MDA-MB-231 (ER- and PR-negative), MCF-7 and T-47D (ER- and PR-positive).MethodsFor the enzyme activity studies, either whole cells were incubated with [14C]progesterone for 2, 4, 8, and 24 hours, or the microsomal/cytosolic fraction was incubated for 15–60 minutes with [3H]progesterone, and the metabolites were identified and quantified. Semi-quantitative RT-PCR was employed to determine the relative levels of expression of 5αR type1 (SRD5A1), 5αR type 2 (SRD5A2), 20α-HSO (AKR1C1), 3α-HSO type 2 (AKR1C3), 3α-HSO type 3 (AKR1C2) and 3β-HSO (HSD3B1/HSD3B2) in the four cell lines using 18S rRNA as an internal control.ResultsThe relative 5α-reductase activity, when considered as a ratio of 5α-pregnanes/4-pregnenes, was 4.21 (± 0.49) for MCF-7 cells, 6.24 (± 1.14) for MDA-MB-231 cells, 4.62 (± 0.43) for T-47D cells and 0.65 (± 0.07) for MCF-10A cells, constituting approximately 6.5-fold, 9.6-fold and 7.1 fold higher conversion to 5α-pregnanes in the tumorigenic cells, respectively, than in the nontumorigenic MCF-10A cells. Conversely, the 20α-HSO and 3α-HSO activities were significantly higher (p < 0.001) in MCF-10A cells than in the other three cell types. In the MCF-10A cells, 20α-HSO activity was 8-14-fold higher and the 3α-HSO activity was 2.5-5.4-fold higher than in the other three cell types. The values of 5αR:20α-HSO ratios were 16.9 – 32.6-fold greater and the 5αR:3α-HSO ratios were 5.2 – 10.5-fold greater in MCF-7, MDA-MB-231 and T-47D cells than in MCF-10A cells. RT-PCR showed significantly higher expression of 5αR1 (p < 0.001), and lower expression of 20α-HSO (p < 0.001), 3α-HSO2 (p < 0.001), 3α-HSO3 (p < 0.001) in MCF-7, MDA-MB-231 and T-47D cells than in MCF-10A cells.ConclusionThe findings provide the first evidence that the 5αR activity (leading to the conversion of progesterone to the cancer promoting 5α-pregnanes) is significantly higher in the tumorigenic MCF-7, MDA-MB-231 and T-47D breast cell lines than in the nontumorigenic MCF-10A cell line. The higher 5αR activity coincides with significantly greater expression of 5αR1. On the other hand, the activities of 20α-HSO and 3α-HSO are higher in the MCF-10A cells than in MCF-7, MDA-MB-231 and T-47D cells; these differences in act...

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Section: Discussionmentioning

confidence: 99%

Activity and expression of progesterone metabolizing 5α-reductase, 20α-hydroxysteroid oxidoreductase and 3α(β)-hydroxysteroid oxidoreductases in tumorigenic (MCF-7, MDA-MB-231, T-47D) and nontumorigenic (MCF-10A) human breast cancer cells

Wiebe

Lewis

2003

BMC Cancer

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“…Polymorphisms in the SRD5A2 gene are not only potentially useful in inheritance studies, but may be also functionally relevant by increasing the susceptibility to undermasculinization [Russell et al, 1994].…”

Section: Discussionmentioning

confidence: 99%

Detection of the G34R Mutation in the 5 Alpha Reductase 2 Gene by Allele Specific PCR and Its Linkage to the 89L Allele among Egyptian Cases

Gad

Khairt²,

Mazen³

et al. 2007

Sex Dev

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The 5 alpha-reductase type 2 deficiency is an autosomal recessive disorder of sexual development among 46,XY individuals. In Egypt, there is a prevalence of a G34R disease underlying mutation. This study aimed to devise a rapid diagnostic method based on allele specific PCR (AS-PCR) and a linked polymorphism (V89L). The results showed that one set of primers was capable to differentiate between normal, heterozygous, and affected individuals efficiently. All 34R mutation carrying sequences had 100% linkage to the 89L allele, contrasting normal ones with low 89L frequencies. This linkage infers a founder effect among Egyptians having G34R mutation.

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“…In contrast, androgen therapy has minimal effects on muscle strength and bone mass in older men with minimal androgen deficiency (16,17). A key issue in androgen action is the tissue-specific effects of the two bioactive metabolites of testosterone, namely dihydrotestosterone (DHT), produced via 5␣ reductase especially in the prostate (18), and estradiol, via aromatase activity particularly in bone (19). How these metabolites influence androgen action on muscle and other tissues is not clear (20).…”

mentioning

confidence: 91%

Randomized Placebo-Controlled Trial of Androgen Effects on Muscle and Bone in Men Requiring Long-Term Systemic Glucocorticoid Treatment

Crawford¹,

Liu²,

Kean³

et al. 2003

The Journal of Clinical Endocrinology & Metabolism

207

128

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Long-term glucocorticoid therapy in men is associated with loss of bone and muscle mass as well as a decrease in serum testosterone. We tested the effect of two androgens, testosterone and its minimally aromatizable analog nandrolone, on muscle mass (dual x-ray absorptiometry), muscle strength (knee flexion and extension by isokinetic dynamometry), bone mineral density (BMD), and quality of life (Qualeffo-41 questionnaire) in 51 men on a mean daily prednisone dose of 12.6 +/- 2.2 mg. Men were randomized, double blind, to testosterone (200 mg mixed esters), nandrolone decanoate (200 mg), or placebo given every fortnight by im injection for 12 months. At 12 months, both androgens increased muscle mass (mean change from baseline +3.5%, +5.8%, and -0.9% in testosterone, nandrolone, and placebo groups, respectively, P < 0.0001) and muscle strength (P < 0.05). Lumbar spine BMD increased significantly only in men treated with testosterone (4.7 +/- 1.1%, P < 0.01). There was no significant change in hip or total body BMD. Testosterone, but not nandrolone or placebo, improved overall quality of life (P < 0.001). These results suggest that androgen therapy may have a role in ameliorating adverse effects of glucocorticoid therapy such as muscle and bone loss and aromatization is necessary for androgen action on bone but not on muscle.

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The Molecular Genetics of Steroid 5α-Reductases

Cited by 40 publications

References 19 publications

Activity and expression of progesterone metabolizing 5α-reductase, 20α-hydroxysteroid oxidoreductase and 3α(β)-hydroxysteroid oxidoreductases in tumorigenic (MCF-7, MDA-MB-231, T-47D) and nontumorigenic (MCF-10A) human breast cancer cells

Activity and expression of progesterone metabolizing 5α-reductase, 20α-hydroxysteroid oxidoreductase and 3α(β)-hydroxysteroid oxidoreductases in tumorigenic (MCF-7, MDA-MB-231, T-47D) and nontumorigenic (MCF-10A) human breast cancer cells

Detection of the G34R Mutation in the 5 Alpha Reductase 2 Gene by Allele Specific PCR and Its Linkage to the 89L Allele among Egyptian Cases

Randomized Placebo-Controlled Trial of Androgen Effects on Muscle and Bone in Men Requiring Long-Term Systemic Glucocorticoid Treatment

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