Influence of CYP19A1 gene expression levels in women with breast cancer: a systematic review of the literature

Breast cancer is the most frequently diagnosed malignant neoplasm in women and is considered a multifactorial disease of unknown etiology. One of the major risk factors is genetic alteration. Changes in CYP19A1 gene expression levels have been associated with increased risk and increased aggressiveness of breast cancer. Increased CYP19A1 gene expression and/or aromatase activity are among the major regulatory events for intratumoral production of estrogens in breast malignant tissues. This systematic review aimed to investigate the influence of CYP19A1 gene expression levels in women with breast cancer. The research was carried out using the PubMed, Scopus, and Web of Science databases. Searches were conducted between February 2 and May 15, 2019. Inclusion criteria were studies published between 2009 and 2019, English language publications, and human studies addressing the gene expression of CYP19A1 in breast cancer. A total of 6.068 studies were identified through PubMed (n=773), Scopus (n=2,927), and the Web of Science (n=2,368). After selecting and applying the inclusion and exclusion criteria, six articles were included in this systematic review. This systematic review provides evidence that increased or decreased levels of CYP19A1 gene expression may be related to pathological clinical factors of disease, MFS, OS, DFS, WATi, markers of metabolic function, concentrations of E1, FSH, and in the use of multiple exons 1 of the CYP19A1 gene in breast cancer.

Pretentious genomic selection signatures in CYP19A1 gene associated with silent estrous behavior in water buffalo in Pakistan

Background: Poor reproductive efficiency of river buffalos hampers the production capabilities of animals. Buffalos are mainly considered poor breeders owing to the constrained expression of estrus behavior. Failure to display heat signs is an indication of improper functionality of signaling peptides to trigger on a series of behavioral changes, which can be detectable by breeders for timely insemination of females. This might cause an animal to be a repeat breeder. Genomic variations underlying synthesis of signaling peptides can be a useful marker to select superior animals with better reproductive efficiency. In this context, the current study was designed to analyze the CYP19A1 gene in Nili-Ravi buffalo. Results: A total of 97 animals were selected and were divided into two groups on the basis of their heat score. PCR amplification and sequencing of the amplicons were performed using the specific sets of primer, and then, sequences were analyzed for novel variants. A total of 11 polymorphic sites were identified illustrating phenotypic variation in the heat score. Most of the loci were found homologous. Single Nucleotide Polymorphisms (SNPs) were analyzed for association with silent estrus. A three-dimensional protein model was also generated to locate the position of exonic SNPs. Conclusion: This study illustrated that polymorphic sites in the CYP19A1 gene provided potential markers for selection of buffalos with better estrus behavior.

Combined Effect of the PGR + 331C > T, CYP17A1 -34A > G and CYP19A1 1531G > A Polymorphisms on the Risk of Developing Endometriosis / Efeito combinado dos polimorfismos PGR + 331C > T, CYP17A1 -34A > G e CYP19A1 1531G > A no risco de desenvolvimento da endometriose

Abstract Purpose To evaluate the magnitude of the association of the polymorphisms of the genes PGR, CYP17A1 and CYP19A1 in the development of endometriosis. Methods This is a retrospective case-control study involving 161 women with endometriosis (cases) and 179 controls. The polymorphisms were genotyped by real-time polymerase chain reaction using the TaqMan system. The association of the polymorphisms with endometriosis was evaluated using the multivariate logistic regression. Results The endometriosis patients were significantly younger than the controls (36.0±7.3 versus 38.0±8.5 respectively, p = 0.023), and they had a lower body mass index (26.3±4.8 versus 27.9±5.7 respectively, p = 0.006), higher average duration of the menstrual flow (7.4±4.9 versus 6.1±4.4 days respectively, p = 0.03), and lower average time intervals between menstrual periods (25.2±9.6 versus 27.5±11.1 days respectively, p = 0.05). A higher prevalence of symptoms of dysmenorrhea, dyspareunia, chronic pelvic pain, infertility and intestinal or urinary changes was observed in the case group when compared with the control group. The interval between the onset of symptoms and the definitive diagnosis of endometriosis was 5.2±6.9 years. When comparing both groups, significant differences were not observed in the allelic and genotypic frequencies of the polymorphisms PGR + 331C > T, CYP17A1 -34A > G and CYP19A1 1531G > A, even when considering the symptoms, classification and stage of the endometriosis. The combined genotype PGR + 331TT/CYP17A1 -34AA/CYP19A11531AA is positively associated with endometriosis (odds ratio [OR] = 1.72; 95% confidence interval [95%CI] = 1.09-2.72). Conclusions The combined analysis of the polymorphisms PGR-CYP17A1-CYP19A1 suggests a gene-gene interaction in the susceptibility to endometriosis. These results may contribute to the identification of biomarkers for the diagnosis and/or prognosis of the disease and of possible molecular targets for individualized treatments.

Resumo Objetivo Avaliar a magnitude de associação de polimorfismos nos genes PGR, CYP17A1 e CYP19A1 no desenvolvimento da endometriose. Métodos Este é um estudo retrospectivo do tipo caso-controle, envolvendo 161 mulheres com endometriose (casos) e 179 controles. Os polimorfismos foram genotipados pela reação em cadeia da polimerase em tempo real utilizando o sistema TaqMan. A associação dos polimorfismos estudados com a endometriose foi avaliada pela regressão logística multivariada. Resultados As pacientes com endometriose eram significativamente mais jovens do que os controles (36,0±7,3 versus 38,0±8,5, respectivamente, p = 0,023), apresentaram um índice de massa corporal menor (26,3±4,8 versus 27,9±5,7, respectivamente, p = 0,006), maior tempo médio de duração do fluxo menstrual (7,4±4,9 versus 6,1±4,4 dias, respectivamente, p = 0,03) e menor tempo médio do intervalo entre as menstruações (25,2±9,6 versus 27,5±11,1 dias, respectivamente, p = 0,05). Uma maior prevalência dos sintomas de dismenorreia, dispareunia, dor pélvica crônica, infertilidade, alterações intestinais e urinárias foi observada no grupo casos comparado ao grupo controle. O tempo médio entre o início dos sintomas e o diagnóstico definitivo de endometriose foi de 5,2±6,9 anos. Comparando os dois grupos, não foram observadas diferenças significativas nas frequências alélicas e genotípicas dos polimorfismos PGR + 331C > T, CYP17A1 -34A > G e CYP19A1 1531G > A, e nem considerando os sintomas, a classificação e o estadiamento da endometriose. O genótipo combinado PGR + 331TT/CYP17A1 -34AA/CYP19A11531AA está associado positivamente com a endometriose (razão de possibilidades [RP] = 1,72; intervalo de confiança de 95% [IC95%] = 1,09-2,72). Conclusões A análise combinada dos polimorfismos PGR-CYP17A1-CYP19A1 sugere uma interação gene-gene na susceptibilidade à endometriose. Estes resultados podem contribuir para a identificação de biomarcadores para o diagnóstico e/ou prognóstico da doença, assim como de possíveis alvos moleculares para um tratamento individualizado.

Polymorphism C242T in the Cyp19 gene in meat sheep / Polimorfismo no gene cyp19 em ovinos de corte

Abstract The objective of this study was to evaluate the frequency of C242T polymorphism on the aromatase gene and the allelic and genotypic frequency of these variants in sheep belonging to four breed groups. Blood samples were collected from 187 animals of four breed groups: Dorper, Santa Inês, Texel and White Dorper, originated from herds in the region of Maringá/PR, Brazil. The genomic DNA was extracted using alkaline extraction, with subsequent amplification of the fragments via PCR with specific primer. The samples resulting from amplification were subjected to digestion process using the Dpn II restriction enzyme and to polyacrylamide gel electrophoresis 10.0% and stained with silver nitrate. Three distinct genotypes were observed: homozygous (CC), heterozygous (CT) and homozygous for no cut (TT). The resulting data were analyzed using the POPGENE software with 5% significance. Genotypic frequencies among the breed groups were: Texel (CC - 0.426; CT - 0.511; TT - 0.064), Dorper (CC - 0.073; CT - 0.732; TT - 0.439), White Dorper (CC - 0.021; CT - 0.255; TT - 0.723) and Santa Inês (CC - 0.115; CT - 0.462; TT - 0.423).

Resumo O objetivo deste trabalho foi avaliar as frequências alélicas e genotípicas do polimorfismo do C242T no gene da aromatase em ovinos pertencentes a quatro grupos raciais. Foram coletadas amostras de sangue de 187 animais de quatro grupos raciais: Dorper, Santa Inês, Texel e White Dorper, provenientes de rebanhos da região de Maringá, PR - BR. O DNA genômico foi extraído utilizando o método de extração alcalina, com posterior amplificação dos fragmentos via PCR com primer específico. As amostras resultantes da amplificação foram submetidas ao processo de digestão com auxilio da enzima restrição Dpn II e submetido à eletroforese em gel de poliacrilamida de 10,0% e corado nitrato de prata. Foram observados três genótipos distintos: Homozigoto (CC), heterozigoto (CT) e homozigoto para não corte (TT). Os dados resultantes foram analisados utilizando o software POPGENE com significância de 5%. As frequências genotípicas entre os grupos raciais foram: Texel (CC - 0,426; CT - 0,511; TT - 0,064), Dorper (CC - 0,073; CT - 0,732; TT - 0,439), White Dorper (CC - 0,021; CT - 0,255; TT - 0,723) e Santa Inês (CC - 0,115; CT - 0,462; TT - 0,423).

A spatial model showing differences between juxtacrine and paracrine mutual oocyte-granulosa cells interactions.

The bidirectional communication between oocytes and granulosa cells are mediated by several factors via a local feedback loop(s). The current model was carried out to study the spatial mutual interaction of porcine denuded oocytes and granulosa cells either in direct contact (juxtacrine) or paracrine co-culture using transwell system. Transwell 0.4 µm polyester membrane inserts were used to permit oocytes-granulosa cells paracrine communication with a distance of 2 mm between them in co-culture. Oocytes were cultured with granulosa cells in a defined basic maturation medium for 44 h. In results, oocyte secreted factors (OSFs; GDF9 and BMP15) temporal expression showed progressive decrement by the end of culture in case of direct contact with granulosa cells while it was increased progressively in the paracrine co-culture groups. However, oocytes that were cultured in direct contact showed a significant increase in blastocyst development after parthenogenetic activation than the paracrine co-cultured ones (20% vs. 11.5%, respectively). By the end of culture, granulosa cell count in direct contact showed a significant decrease than the indirect co-culture group (1.2 × 105 cell/mL vs. 2.1 × 105 cell/mL, respectively). Steroids (P4 and E2) and steriodogenesis enzymes mRNA levels showed significant temporal alterations either after 22 h and 44 h of IVM in both juxtacrine and paracrine co-culture systems (P ≤ 0.05). CX43 was much more highly expressed in the granulosa of the direct contact group than the indirect co-culture group. These results indicate the difference in mutual communication between oocytes and granulosa cells that were cocultured either in direct contact (juxtacrine) or with a short distance (paracrine) and propose a new paradigm to study different ovarian follicular cells interaction.

Aromatase activity in brain and ovary: Seasonal variations correlated with circannual gonadal cycle in the catfish, Heteropneustes fossilis.

Seasonal variations in the aromatase activity in H. fossilis estimated by a microassay were correlated with the sex steroids, vitellogenin in and ovarian weight during circannual reproductive cycle. In the female catfish, aromatase activity was detectable in the hypothalamus throughout the year whereas in ovary only during active vitellogenesis. In the catfish, hypothalamic aromatase levels increased two times during annual gonadal cycle, once in a fully gravid fish and then in a reproductively quiescent fish. On the other hand, increase in the ovarian aromatase activity was observed only during vitellogenesis, which showed a direct correlation with plasma levels of sex steroids. Further, plasma levels of testosterone and estradiol suggested a precursor-product relationship. At the completion of vitellogenesis, ovarian aromatase activity declined sharply resulting in elevation of plasma testosterone levels, which in turn could be utilized as substrate by the hypothalamic aromatase whose activity was the highest in the postvitellogenic catfish. At least two isoforms of gene, cyp19a and cyp19b, coding for aromatase in ovary and brain respectively were expressed in the catfish. Aromatase activity was more concentrated in those areas of catfish brain, which have been implicated in the control of reproduction.

CYP19 gene variant confers susceptibility to endometriosis-associated infertility in Chinese women

An aromatase encoded by the CYP19 gene catalyzes the final step in the biosynthesis of estrogens, which is related to endometriosis development. To assess the association of CYP19 gene polymorphisms with the risks of endometriosis, chocolate cysts and endometriosis-related infertility, a case-control study was conducted in Chinese Han women by recruiting 225 healthy control females, 146 patients with endometriosis, 94 endometriosis women with chocolate cyst and 65 women with infertility resulting from endometriosis, as diagnosed by both pathological and laparoscopic findings. Individual genotypes at rs2236722:T>C, rs700518:A>G, rs10046:T>C and [TTTA]n polymorphisms were identified. Allelic and genotypic frequencies were compared between the control group and case groups by chi-square analysis. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were determined by logistic regression analysis to predict the association of CYP19 gene polymorphisms with the risk of endometriosis, the related chocolate cysts and infertility. The genotype distributions of the tested CYP19 gene polymorphisms were not significantly different between the healthy control group and the endometriosis/endometriosis with the chocolate cyst group. However, the CYP19 rs700518AA genotype was significantly associated with an increased risk of endometriosis-related infertility (55.4% in the infertility group vs 25.3% in the control group, P<0.001; OR (95% CI): 3.66 (2.06-6.50)) under the recessive form of the A allele. Therefore, we concluded that in Chinese Han females CYP19 gene polymorphisms are not associated with susceptibility to endometriosis or chocolate cysts, whereas CYP19 rs700518AA genotype confers genetic susceptibility to endometriosis-related infertility.

Aromatase excess syndrome presenting with prepubertal gynecomastia in an Egyptian child with type 1 neurofibromatosis.

A romatase excess syndrome (AEXS) is a rare autosomal dominant disorder characterized by prepubertal gynecomastia, it responds well to medical treatment. In the absence of prompt suspicion, it can expose the patient to the risk of unnecessary surgical intervention. Up to our best knowledge, the association between AEXS and neurofibromatosis type 1 (NF1) was not reported before. Here, we describe a AEXS presenting with prepubertal gynecomastia in an Egyptian child with NF1 that improved with aromatase inhibitors.

Culture of bovine ovarian follicle wall sections maintained the highly estrogenic profile under basal and chemically defined conditions

Follicle cultures reproduce in vitro the functional features observed in vivo. In a search for an ideal model, we cultured bovine antral follicle wall sections (FWS) in a serum-free defined medium (DM) known to induce 17β-estradiol (E2) production, and in a nondefined medium (NDM) containing serum. Follicles were sectioned and cultured in NDM or DM for 24 or 48 h. Morphological features were determined by light microscopy. Gene expression of steroidogenic enzymes and follicle-stimulating hormone (FSH) receptor were determined by RT-PCR; progesterone (P4) and E2 concentrations in the media were measured by radioimmunoassay. DM, but not NDM, maintained an FWS morphology in vitro that was similar to fresh tissue. DM also induced an increase in the expression of all steroidogenic enzymes, except FSH receptor, but NDM did not. In both DM and NDM, there was a gradual increase in P4 throughout the culture period; however, P4 concentration was significantly higher in NDM. In both media, E2 concentration was increased at 24 h, followed by a decrease at 48 h. The E2:P4 ratio was higher in DM than in NDM. These results suggest that DM maintains morphological structure, upregulates the expression of steroidogenic enzyme genes, and maintains steroid production with a high E2:P4 ratio in FWS cultures.

Association study of the oestrogen signalling pathway genes in relation to age at natural menopause.

Genetic factors play a significant role in influencing the variation of age at natural menopause (AANM). Estrogen receptor beta (ESR2), is an important factor in the mechanism of action of estrogen, while the aromatase gene (CYP19) and the 17-alpha-hydroxylase gene (CYP17) are involved in the biosynthesis of estrogen. We tested whether polymorphisms of ESR2, CYP19 and CYP17 genes are associated with AANM in Caucasian females. A total of 52 SNPs (17 for ESR2, 28 for CYP19, and 7 for CYP17) were successfully genotyped for 229 Caucasian women having experienced natural menopause. Comprehensive statistical analyses focusing on the association of these genes with AANM were conducted. The effects of age, height and age at menarche on AANM were adjusted when conducting association analyses. We found that six SNPs (2, 6-7, 9, 13 and 16) within ESR2 were not significantly associated with AANM after Bonferroni correction. However, two blocks of ESR2 were associated with AANM. For CYP19, two SNPs (24 and 27) were nominally associated with AANM. No significant association was observed between CYP17 and AANM. Our results suggest that genetic variation in the ESR2 and CYP19 genes may influence the variation in AANM in Caucasian women.

El splicing alternativo del exón 5 de la citocromo p450 aromatasa podría ser un mecanismo de regulación de la producción de estrógenos en humanos / Exon 5 alternative splicing of the cytochrome P450 aromatase could be a regulatory mechanism for estrogen production in humans

La enzima P450 aromatasa (P450Aro) participa en la síntesis de estrógenos a partir de andrógenos. La mutación c655G>A, descripta en forma heterocigota en una niña y en forma homocigota en un hombre adulto, ambos con déficit de aromatasa, genera la disrupción del sitio dador de splicing exón5-intrón5. Se ha postulado que la retención del intrón5 y la generación de una proteína truncada inactiva serían las consecuencias de esta mutación. Sorpresivamente, la paciente presentó desarrollo espontáneo de mamas y niveles puberales de estradiol, sugiriendo una actividad aromatasa (AA) residual. En principio postulamos que la mutación c655G>A generaría la pérdida del exón5 con conservación del marco de lectura, generándose una proteína con menor actividad que podría explicar el déficit parcial. La expresión del ARNm sin exón5 (ARNm- E5) en linfocitos de la paciente sugiere una asociación entre la pérdida del exón y la presencia de la mutación; posteriormente confirmada realizando ensayos de splicing en células Y1. Sin embargo, la expresión del cDNAE5 en células Y1 presentó una AA nula que no explicaría un déficit parcial. La expresión del ARNm-E5 fue detectada en placenta, testículo y adrenal humanos como una variante de splicing normal. Estos resultados indicarían la ocurrencia de splicing alternativo (SA) en la zona codificante de P450Aro como un posible mecanismo regulador de la producción de estrógenos en tejidos esteroidogénicos humanos. La mutación c655G>A podría alterar los mecanismos fisiológicos reguladores del SA del exón5 favoreciendo su exclusión. De esta forma, bajos niveles de ARNm+E5 podrían expresarse aun en presencia de la mutación explicando el fenotipo de déficit parcial observado en la paciente.

P450 aromatase (P450Aro), involved in androgen to estrogen conversion, is encoded by the CYP19 gene. P450Aro c655G>A mutation described in heterozygous form in a girl and in homozygous form in an adult male with P450Aro deficiency results in an aberrant splicing due to disruption of a donor splice site. A truncated inactive protein would be expected if intron5 is retained. Surprisingly, the girl described with this mutation showed spontaneous breast development and pubertal estradiol (E2) levels suggesting residual P450Aro activity (AA). Formerly, we postulate the in frame E5 skipping as a consequence of this mutation generating a protein with some degree of activity. When P450Aro mRNA expression was analysed from patient's lymphocytes, an aberrant spliced mRNA lacking E5 (-E5mRNA) was detected, suggesting an association between E5 skipping and the presence of the mutation. Splicing assays in Y1 cells confirmed this association. -Ex5 cDNA expression in Y1 cells resulted in an inactive protein that could not explain patient's phenotype. Exon 5 might be predicted as a poorly defined exon suggesting a susceptibility to splicing mutations and physiological alternative splicing (AS) events. Therefore, -Ex5mRNA was assessed as a natural occurring alternative transcript in normal human steroidogenic tissues. As P450Aro -E5mRNA expression was detected in human term placenta, prepubertal testis and prepubertal adrenal, we might speculate that AS of P450Aro coding region would occur in humans and would be involved in the complex AA regulation. Furthermore, tissue specific regulation of AS might suggest low expression of +E5mRNA from the c655G>A allele explaining residual AA evidenced in the affected girl.

Estrogens and male reproduction: a new concept

The mammalian testis serves two main functions: production of spermatozoa and synthesis of steroids; among them estrogens are the end products obtained from the irreversible transformation of androgens by a microsomal enzymatic complex named aromatase. The aromatase is encoded by a single gene (cyp19) in humans which contains 18 exons, 9 of them being translated. In rats, the aromatase activity is mainly located in Sertoli cells of immature rats and then in Leydig cells of adult rats. We have demonstrated that germ cells represent an important source of estrogens: the amount of P450arom transcript is 3-fold higher in pachytene spermatocytes compared to gonocytes or round spermatids; conversely, aromatase activity is more intense in haploid cells. Male germ cells of mice, bank voles, bears, and monkeys express aromatase. In humans, we have shown the presence of a biologically active aromatase and of estrogen receptors (alpha and ß) in ejaculated spermatozoa and in immature germ cells in addition to Leydig cells. Moreover, we have demonstrated that the amount of P450arom transcripts is 30 percent lower in immotile than in motile spermatozoa. Alterations of spermatogenesis in terms of number and motility of spermatozoa have been described in men genetically deficient in aromatase. These last observations, together with our data showing a significant decrease of aromatase in immotile spermatozoa, suggest that aromatase could be involved in the acquisition of sperm motility. Thus, taking into account the widespread localization of aromatase and estrogen receptors in testicular cells, it is obvious that, besides gonadotrophins and androgens, estrogens produced locally should be considered to be physiologically relevant hormones involved in the regulation of spermatogenesis and spermiogenesis.

DNA isolation from goat blood using different brands of household detergents and its downstream application.

Rapid isolation of DNA from goat blood using different brands of detergents available in Indian market, is reported. The integrity and efficiency of these DNA preparations were compared with genomic DNA isolated by a standard kit (Flexi gene DNA kit), using amplification of exon 2 of CYP19 (aromatase) gene. The similar and significant amplification of this gene was obtained using genomic DNA isolated by kit and various detergents. However, among the detergents used, the Rin and Ezee were found to be the best to get DNA of high purity comparable to that obtained by kit.