Ilma Simoni Brum

Association between androgen receptor gene cag repeat polymorphism and plasma testosterone levels in postmenopausal women

Objectives: The biologic action of androgens in target cells depends on plasma androgen levels and receptor transcriptional activity. We investigated the relationship between androgen receptor (AR) CAG repeat polymorphism, serum androgen levels, and anthropometric, metabolic, and hormonal variables in 39 postmenopausal women, taking into consideration the patterns of X-chromosome inactivation. Methods: Genomic DNA was extracted from peripheral leukocytes. Polymerase chain reactions (PCRs) were performed to amplify the polymorphic (CAG)n repeat of the human AR gene, which were analyzed with GeneScan software (Applied Biosystems, Foster City, CA). The X-chromosome inactivation analysis was based on the AR gene methylation patterns. Results: The mean age of participants was 54.7 years; mean age at menopause was 48 years. The number of CAG repeats ranged from 15 to 30, with a median length of 23. Analysis of X-chromosome inactivation patterns showed 19 cases with a degree of skewing (DS) ≥70% and seven with a DS ≥90%. The X-weighted CAG repeat biallelic mean was significantly lower in individuals with total testosterone (TT)greater than 0.56 ng/mL (group mean) than in thegroup with TT≤0.56 (P=.018). No dfference was observed between the groups regarding dehydroepiandrosterone suffate (DHEA-S). Plasma TT was signfitcantly higher in the group with the smaller X-weighted CAG repeat biallelic mean (P=.01). Free androgen index (FAI) was also signficantly higher in this group (P=.033). Testosterone levels and FAI were inversely correlated to X-weighted CAG repeat biallelic mean. Conclusion: Our data indicate an association between testosterone plasma levels and AR CAG repeats in postmenopausal women, and suggest that plasma levels of androgens in postmenopausal women may be related to variants of the AR gene.

Polymorphic CAG and GGC Repeat Lengths in the Androgen Receptor Gene and Prostate Cancer Risk : Analysis of a Brazilian Population

Variations in transcriptional activity of the androgen receptor (AR) are related to polymorphic CAG and GGC repeats in exon 1 of the AR gene. We investigated the association between CAG and GGC repeat length and the risk of prostate cancer in a case-control study from a Brazilian population. We evaluated 49 patients and 51 healthy controls. DNA was extracted from peripheral leukocytes and the AR gene was analyzed by fragment analysis (GeneMapper software, Applied Biosystems, Foster City, California, USA). CAG and GGC mean lengths were not different between cases and controls. The risk for prostate cancer was higher for CAG repeats ≤ 21 (OR = 2.44 [95% CI 1.03–5.81]) as well as for total repeat lengths (CAG + GGC) ≤37 (OR = 2.46 [95% CI 0.98–6.18]). GGC repeats (≤17 and > 17) were not associated with risk for prostate cancer (OR = 1.13 [95% CI 0.47–2.75]). In conclusion, fewer number of CAG repeats and total repeats (CAG + GGC) in the AR gene may be associated with increased risk for prostate cancer.

Reactive oxygen and nitrogen species balance in the determination of thyroid hormones-induced cardiac hypertrophy mediated by renin–angiotensin system

Role of reactive oxygen species (ROS)/nitric oxide (NO) balance and renin-angiotensin system in mediating cardiac hypertrophy in hyperthyroidism was evaluated in an in vivo and in vitro experimental model. Male Wistar rats were divided into four groups: control, thyroid hormone, vitamin E (or Trolox, its hydrosoluble analogue), thyroid hormone+vitamin E. Angiotensin II receptor (AT1/AT2) gene expression, immunocontent of AT1/AT2 receptors, angiotensinogen, NADPH oxidase (Nox2), and nitric oxide synthase isoforms, as well as ROS concentration (hydrogen peroxide and superoxide anion) were quantified in myocardium. Thyroid hormone increased ROS and NO metabolites, iNOS, nNOS and eNOS isoforms and it was accompanied by cardiac hypertrophy. AT1/AT2 expression and the immunocontent of angiotensinogen and Nox2 were enhanced by thyroid hormone. Antioxidants reduced ROS levels, Nox2, AT1/AT2, NOS isoforms and cardiac hypertrophy. In conclusion, ROS/NO balance may play a role in the control of thyroid hormone-induced cardiac hypertrophy mediated by renin-angiotensin system.

Estrogen receptor-, bcl-2 and c-myc gene expression in fibroadenomas and adjacent normal breast: Association with nodule size, hormonal and reproductive features

Fibroadenomas are the most common benign lump in females. The study of gene alterations and/or deregulation in reproductive years may help explain hormonal physiological processes involved in nodule development and evolution. The objective was to compare ER-alpha, c-myc, and bcl-2 gene expression in breast fibroadenomas and in normal tissue and evaluate menstrual cycle, parity, and oral contraceptive influences. Fifty-seven premenopausal women (14-49 years) undergoing surgical removal of fibroadenomas were selected. Samples from fibroadenomas and circumjacent normal tissue were obtained for RT-PCR paired analysis. Patients were divided in groups according to menstrual cycle, use of contraceptives and parity. Tissue from 32 patients was adequate for RT-PCR. Paired analysis showed higher expression of ER-alpha (P=0.012) and bcl-2 (P=0.001) in fibroadenomas than in normal breast, while c-myc presented a similar expression (P=0.655). ER-alpha was higher in fibroadenomas of patients in follicular phase versus contraceptive users and normal tissue (P=0.003); bcl-2 was higher in fibroadenomas of patients in luteal phase than in the normal samples from all groups (P=0.007). c-myc did not differ according to menstrual cycle, but was higher in fibroadenomas>3 cm versus<3 cm (P=0.015) and in nulliparous women (P=0.04). A positive correlation between c-myc levels and fibroadenoma diameter was demonstrated (r=0.536; P=0.007). Nulliparous mean nodule diameter was superior than parous women (P=0.008). In conclusion, the expression of ER-alpha, bcl-2 and c-myc depends on hormonal and reproductive factors, with a possible contribution to lump formation and evolution.

The 5alpha-reductase type 1, but not type 2, gene is expressed in anagen hairs plucked from the vertex area of the scalp of hirsute women and normal individuals

The aim of the present study was to determine the expression of the genes for type 1 (SDR5A1) and type 2 (SDR5A2) 5alpha-reductase isoenzymes in scalp hairs plucked from 33 hirsute patients (20 with polycystic ovary syndrome and 13 with idiopathic hirsutism) and compare it with that of 10 men and 15 normal women. SDR5A1 and SDR5A2 expression was estimated by RT-PCR using the gene of the ubiquitously expressed protein 2-microglobulin as an internal control. The results are expressed as arbitrary units in relation to beta2-microglobulin absorbance (mean SEM). SDR5A2 expression was not detected in any hair samples analyzed in this study. No differences were found in SDR5A1 mRNA levels between men and normal women (0.78+/-0.05 vs 0.74+/-0.06, respectively). SDR5A1 gene expression in the cells of hair plucked from the scalp of normal women (0.85+/-0.04) and of women with polycystic ovary syndrome (0.78+/-0.05) and idiopathic hirsutism (0.80+/-0.06) was also similar. These results indicate that SDR5A1 gene expression in the follicular keratinocytes from the vertex area of the scalp seems not to be related to the differences in hair growth observed between normal men and women and hirsute patients. Further studies are needed to investigate the expression of the 5alpha-reductase genes in other scalp follicular compartments such as dermal papillae, and also in hair follicles from other body sites, in order to elucidate the mechanism of androgen action on the hair growth process and related diseases.

Protein Expression of Estrogen Receptors α and β and Aromatase in Myometrium and Uterine Leiomyoma

Background: Leiomyomas are the most common tumors of the female reproductive tract and a major public health problem. The mechanism of tumorigenesis is unknown, but evidence suggests that estrogens regulate cell proliferation and myoma growth. This effect might be due to different amounts of estrogen receptors (ERα and ERβ) in normal and myoma tissues and overexpression of aromatase P450 in myomas. Purpose: To assess protein expression of ERs and aromatase in leiomyomas and normal adjacent myometrium of premenopausal women. Methods: Samples were collected from 12 premenopausal women admitted for abdominal hysterectomy due to fibroids. Results: The protein expression of ERα, ERβ and aromatase was similar in leiomyoma and normal myometrium (p = 0.239, p = 0.695 and p = 0.203, respectively). Conclusions: In this analysis of 12 matched leiomyoma and myometrial samples, the data do not support the theory that overexpression ERα, ERβ and aromatase in uterine leiomyomas compared to adjacent myometrium are the cause of tumor growth. The estrogens may exert their growth-stimulatory effects on leiomyomas intermediated by other elements, such as cytokines and growth or apoptosis factors. The effect of estrogen on the growth and development of fibroids is complex and far from being completely understood.

CCR2 and CCR5 genes polymorphisms in benign prostatic hyperplasia and prostate cancer

Benign prostatic hyperplasia (BPH) and prostate cancer (PCa) are two chronic conditions, very common in aged men, that have been associated to inflammatory process. Chemokines and their receptors are recognized as critical mediators of inflammatory responses, they regulate immune cell migration and are implicated in tumor pathogenesis. The impact of two chemokine receptor gene polymorphisms, CCR2-64I (rs1799864) and CCR5-Δ32 (rs333), was evaluated in BPH and PCa. 385 DNA samples (130 BPH, 136 PCa, 119 healthy control) were genotyped. The allele frequencies were similar among control, BPH and PCa groups. Median of serum PSA levels was different between groups: 0.79, 1.45 and 6.91 ng/mL in control, BPH and PCa groups, respectively (all p<0.001). The prostate volume median was 20.00 cm(3) in the control group, thus, lower than BPH (35.35 cm(3)) and PCa (35.80 cm(3)) (both p<0.001), nevertheless no statistical significant difference was observed between BPH and PCa patients (p=0.172). Remarkably, CCR2-64I was a protective factor to PCa when compared with BPH (OR=0.550; 95%CI=0.311-0.975), although the statistically significant difference was lost after correction for multiple comparisons. No significant associations of CCR5-Δ32 variant were observed with BPH, PCa or PCa clinicopathologic status. Our data suggest the influence of CCR2-64I variant in the development of prostate cancer.

Biologia molecular do câncer cervical

Carcinogenesis involves several steps. Disorders of the cytogenetic balance occur during the evolution from normal epithelium to cervical cancer. Several studies support the hypothesis that the Human Papiloma Virus (HPV) infection is associated to development of premalignant and malignant lesions of cervical cancer. In this review we show the basis to understand cervical oncogenesis. The cell cycle is controlled by protooncogenes and supressive genes. This orchestrated cell cycle can be affected by virus such as HPV. Of special interest in the cervical carcinogenesis are the HPV subtypes 16 and 18. How HPV immortalizes cervical cells is not fully understood. Advances have been made in the application of molecular biology techniques in the understanding of this mechanism. Once established, these techniques will lead to a better assessment of cervical neoplasias and help the development of new therapies, hopefully less invasive and more effective.

Metformin modulates PI3K and GLUT4 expression and Akt/PKB phosphorylation in human endometrial stromal cells after stimulation with androgen and insulin

OBJECTIVE To assess the effect of metformin on expression of Akt, ERK, PI3K and GLUT4, proteins associated with the growth factor signaling cascade, in human endometrial stromal cells after stimulation with androgen and insulin. STUDY DESIGN Primary culture of endometrial stromal cells were stimulated in different groups with estrogen, progesterone, androgen and insulin and treated with metformin for 10min, 24h and 48h. After 14 days, proteins were extracted for Western blot analysis. RESULTS PI3K and GLUT4 expression were increased in the insulin-treated group and further attenuated when metformin was added. The ERK protein was not affected, whereas the Akt phosphorylation was significantly decreased by the action of metformin. CONCLUSION Metformin affects human endometrial stromal cells by acting on proteins related to growth factors, usually increasing their expression when combined with insulin. Akt phosphorylation was inhibited by metformin, possibly due to its anti-proliferative action.

Androgen-Dependent Expression of c-jun and c-fos in Human Non-Transformed Epithelial Prostatic Cells: Association with Cell Proliferation

Objective: To assess the effect of dihydrotestosterone (DHT) on the gene expression of c-fos and c-jun and on the proliferation of human non-transformed epithelial prostatic (HNTEP) cells. Methods: Cell proliferation (MTT) and c-fos and c-jun mRNA expression (RT-PCR) were determined in cells treated with DHT (10–8, 10–10, and 10–13M) or with control medium. Results: DHT 10–13 M had a significant stimulatory effect on cell proliferation (p < 0.05) and c-fos and c-jun gene expression when compared to cells treated with higher concentrations of this hormone (10–10 and 10–8M) or with the control group. Conclusions: Our data demonstrate that the increase in c-fos and c-jun expression and cell growth in HNTEP cells is maximal with the lowest DHT concentration (10–13M). These proto-oncogenes may play a role in the control of hormone responsiveness and cell proliferation in HNTEP cells.