Functional Identification of Compound Heterozygous Mutations in the CYP17A1 Gene Resulting in Combined 17α-Hydroxylase/17,20-Lyase Deficiency

BACKGROUND: We previously reported a patient with congenital adrenal hyperplasia (CAH) with compound heterozygous mutations in the cytochrome P450 17A1 (CYP17A1) gene. One allele had a p.His373Leu and the other a new p.Glu383fsX36 mutation. The aim of this study was to investigate the functional properties of a new allele present in a compound heterozygote of CYP17A1. METHODS: To understand how p.His373Leu and p.Glu383fsX36 affect P450c17 enzymatic activity, wild type and mutant CYP17A1 cDNAs were cloned into flag-tagged pcDNA3 vector and introduced into human embryonic kidney cells 293T (HEK293T) cells. Protein expression levels of CYP17A1 were then analyzed. And the activities of 17α-hydroxylase and 17,20-lyase of CYP17A1 were evaluated by measuring the conversion of progesterone to 17α-hydroxyprogesterone and of 17α-hydroxypregnenolone to dehydroepiandrosterone, respectively. In addition a computer model was used to create the three-dimensional structure of the mutant CYP17A1 enzymes. RESULTS: Production of the p.His373Leu mutant protein was significantly lower than that of the wild type protein, and the p.Glu383fsX36 protein was hardly produced. Similarly the enzymatic activity derived from the p.His373Leu mutant vector was significantly lower than that obtained from the wild type vector, and little activity was obtained from the p.Glu383fsX36 vector. Three-dimensional modeling of the enzyme showed that p.His373 was located in region important for heme-binding and proper folding. Neither the p.His373Leu nor the p.Glu383fsX36 mutant protein formed a heme-binding structure. CONCLUSION: Enzyme activity measured in both mutants disappeared completely in both 17α-hydroxylase and 17,20-lyase. This result accounts for the clinical manifestations of the patient with the compound heterozygous CYP17A1 mutations.

Mechanism of Bushen huoxue huatan recipe improving hyperandrogenism in androgen-induced sterile rats / 第二军医大学学报

Objective To observe the therapeutic effect of Bushen huoxue huatan recipe (BHHR) on androgen-induced sterilized rats (ASR) and the expression of androgen synthase and metabolic enzymes in the ovary of ASR before and after treatment with BHHR, and to discuss the possible mechanism. Methods Female SD rats of 9-day old were injected subcutaneously with testosterone propionate (1. 25 mg) to create model. The model ratswere randomly divided into 3 groups: model group (treated with distilled water by gastrogavage, 10 mL/kg)' metformin therapy group (gastrogavage, 0. 1 g/kg) and BHHR therapy group (gastrogavage, 10 mL/kg)' with 13 animals in each group. Ten rats with normal estrous cycle served as normal controls. The body mass' sexual cycle recovery and ovary mass/body mass ratio were observed after 28-day treatment. Serum testosterone level was measured by radioimmunoassay; the expressions of 3(-hydroxylsteroid dehyrogenase (3β-HSD) cytochrome P450 17α-crhydroxylase/17, 20-lyase (CYP17) and P450 aromatase (P450arom) in ovary were detected by quantitative immunohistochemistry method. Results (1) Significantly more rats in the metformin and BHHR groups had sexual cycle recovery compared with that in themodtl group (P 0. 05). Conclusion BHHR can reduce serum testosterone levels in ASR rat, which might be through up-regulating the expression of the androgen metabolism enzyme P450arom.

Clinical study on 48 cases with complete 17α-hydroxylase deficiency / 中华妇产科杂志

Objective To investigate efficient diagnosis and treatment of 17α-hydroxylase (17OHD) deficiency by summarizing clinical characteristics of those patients.Methods From January 1983 to January 2010,48 cases with 17OHD in Peking Union Medical College Hospital were studied retrospectively.Results Among 48 patients with 17OHD,karyotype analysis showed,12 cases with 46,XX and 36 cases with 46,XY.The 46,XX karyotype and 46,XY karyotype with complete 17OHD had typical clinical presentation of amenorrhea [ 12/12,100％ ( 36/36 ) ],no typical spontaneous puberty [ 12/12,13.9％ (5/36) ],Hypertension [ 11/12,100％ ( 36/36 ) ],hypokalemia [ K +:( 2.6 ± 0.7 ),( 2.8 ± 0.7 )mmol/L],hypergonadotropin [ follicle-stimulatinghormone ( FSH ):( 51 ± 35 ),( 79 ± 46 ) U/L,luteinizing hormone( LH ):( 27 ± 14 ),(49 ± 37 ) U/L ],impaired production of sex hormones [ testosterone(T):0.003,0.005 nmol/L; estradiol ( E2 ):26.86,10.64 pmol/L ],hyper-progesterone [ (P):( 32 ± 15 ),( 29 ± 23) nmol/L],impaired production of 17α-hydroxyprogesterone ( 17α-OHP ) [ ( 2.5 ± 1.1 ),( 2.4 ±1.7) nmol/L],ACTH hypersecreation (91.8,114.0 pmol/L).ACTH stimulating test did not elevated in 17α-OHP and cortisol.Conclusion When patients with elevated basal serum levels of progesterone higher than that of ovulation period in addition to clinical symptoms,examination about 17OHD should be warranted.

Limited Expression of Cytochrome P450 17alpha-Hydroxylase/17,20-Lyase in Prostate Cancer Cell Lines

PURPOSE: Cytochrome P450 17alpha-hydroxylase/17,20-lyase (CYP17A1) is a key enzyme in the androgen biosynthesis pathway. CYP17A1 has been focused on because of the promising results of a potent CYP17A1 inhibitor in the treatment of castration-resistant prostate cancer (CRPC). A hypothesis that intratumoral androgenesis may play a role in the progression of CRPC has recently been postulated. Thus, we evaluated whether commonly used prostate cancer cell lines express CYP17A1. MATERIALS AND METHODS: Androgen-sensitive LNCaP and androgen-insensitive PC-3 and DU145 cells were used. To evaluate the expression of CYP17A1 protein and RNA, we performed Western blotting and RT-PCR, respectively. RESULTS: We were unable to detect either CYP17A1 protein or RNA in any of the cell lines tested. We failed to detect any expression of CYP17A1, despite several repetitions of these techniques under different conditions. CONCLUSIONS: The expression of CYP17A1 protein and RNA in LNCaP, PC-3, and DU145 cells appears to be either absent or too low for detection. The mechanism of action of abiraterone acetate, a CYP17A1 inhibitor, may be related more to adrenal androgen blockade than to intratumoral androgenesis.

Establishment of an assay for detection of gene mutation in congenital adrenal hyperplasia / 中华检验医学杂志

Objective To establish a method of gene mutation detection for congenital adrenal hyperplasia (CAH) by using sequencing, single nucleotide polymorphisms (SNP) analysis and T-A cloning. Methods The blood samples of 33 patients with 21-hydroxylase deficiency (21-OHD) , 2 patients with 17α-hydroxylase deficiency (17-OHD) , the parents of all the patients and 105 healthy children were collected. Genomic DNA were extracted form the blood samples. To detect the gene mutation of CYP21A2,highly specific primers for CYP21A2 gene were designed according to the sequence differences between CYP21A2 gene and its pseudogene. The whole CYP21A2 gene was amplified and sequenced. SNP analysis and TA cloning of PCR products were also carried out. The molecular diagnosis of 17-OHD was based on the amplification and sequencing of CYP17A1 gene. Results The corresponding gene mutations was determined in all the patients based on the method established in this study. Thirteen mutations of CYP21A2 gene were identified in 33 patients with 21-OHD. The 3 most frequent mutation of CYP21A2 gene were IVS2-13A/C >G, p. I172N and chimeric mutation, which accounted for 32% (21/66) ,27% (18/66) and 15% (10/66) respectively. Ninety-one persent mutations of CYP21A2 gene resulted from pseudogene conversion. In 2 patients with 17-OHD, homozygous mutations of CYP17A1 gene, IVS4-6A > G and p. 487_489del were identified separately. All the gene mutations detected in the patients were inherited from their parents. No mutation of CYP21A2 gene or CYP17A1 gene was found in the healthy children. Conclusion A method of gene mutation detection for CAH has been established. It will be beneficial to clinical diagnosis of CAH.

Incomplete P450 17 alpha enzyme deficiency:report of six cases / 中华妇产科杂志

Objectives To summarize the characteristics,differential diagnosis and management of incomplete 17 alpha-hydroxylase/17,20-1yase deficiency(17 OHD)of Chinese patients.Methods Six cases of incomplete 17 OHD from Peking Union Medical College Hospital were studied retrospectively through analyzing their clinical data,and the molecular pathogenic mechanism was discussed after literature review.Results Four cases of 46,XX incomplete 17 OHD were reported.The clinical characteristics included female phenotype,various degrees of breast development and absent or sparse axillary/pubic hair, oligomenorrhea or secondary amenorrhea,recurrent luteinized ovarian cysts,hypogonadism with persistent hyperprogesteronemia or high serum 17 alpha-hydroxyprogesterone level,with or without hypokalemic hypertension.There were also 2 cases of 46,XY incomplete 17 OHD,in which ambiguous genitalia were present besides hypokalemic hypertension.Conclusions Incomplete 17 OHD is a very rare form of congenital enzymatic deficiencies of steroid synthesis,which should be included in the differential diagnosis when there are menstrual disorders,sexual infantilism,recurrent ovarian cysts or ambiguous genitalia.Under such circumstances,hyperprogesteronemia offers a valuable clue for further investigation.

Changes in the gene expression of steroidogenic enzymes in the brain of morphine dependence rats / 中华麻醉学杂志

Objective To investigate the expression of mRNAs for cholesterol side chain cleavage enzyme (p450 scc), 17?-hydroxylase / C17-20 lyase (P450 C17) and 3?-hydroxysteroid dehydrogenase (3?-HSD) in frontal cortex, amygdala, hippocampus, striatum and midbrain of morphine dependence rats.Methods Twenty-one male SD rats were randomly divided into 3 groups with 7 animals in each group: (1) control group (group C) ; (2) morphine dependence group (group D) and (3) morphine withdrawal group (group W). In group D and W the animals were given intraperitoneally increasing doses of morphine starting from 5 mg?kg-1 to 10, 15, 20, 30, 40 and 50 mg?kg-1 twice a day for 7 days. In group C the animals were given normal saline instead of morphine. In group C and D the animals were decapitated 1 h after last injection. In group W naloxone 2 mg?kg-1 was given 1h after last morphine injection, then the animals were decapitated 30 min after withdrawal symptoms were observed. The brains were immediately removed and the frontal cortex, amygdala, hippocampus, striatum and midbrain were separated. The expression of mRNAs for the three steroidogenic enzymes in the different brain regions of rats were determined by RT-PCR.Results The expression of P450scc mRNA in striatum and 3?-HSD mRNA in amygdala, striatum and frontal cortex decreased in group D compared with group C. The expression of 3?-HSD mRNA increased in morphine withdrawal group compared with group D.Conclusion The gene expression of steroidogenic enzymes decreases in some brain regions of morphine dependence rats, suggesting that endogenous neurosteroids might be involved in morphine dependence.