Aromatase overexpression enhances the stimulatory effects of adrenal androgens on MCF7 breast cancer cells

Review on Natural Agents as Aromatase Inhibitors: Management of Breast Cancer

Breast cancer is a prevalent type of cancer that is typically hormone-dependent, caused by estrogen. Aromatase inhibitors are frequently utilised in the treatment of hormonereceptor- positive breast cancer because they prevent the enzyme aromatase from converting androgens to estrogens. Natural medicines with aromatase inhibitory characteristics have attracted interest as potential alternatives or complementary therapy to manufactured medications. This review discusses the function of natural agents as aromatase inhibitors in treating breast cancer. A variety of natural compounds have been investigated for their capacity to inhibit aromatase activity and lower estrogen levels. These agents include resveratrol from red wine and grapes, curcumin from turmeric extract and green teahigh in catechins, and other flavonoids such as genistein, luteolin and quercetin. It has been demonstrated that by decreasing estrogen synthesis, they can slow the growth of breast cancer cells that are dependent on estrogen. However, the clinical evidence supporting their efficacy and safety in breast cancer treatment is inadequate. More research is required to investigate the therapeutic potential of natural medicines, such as aromatase inhibitors, in treating breast cancer. The clinical trials are required to assess their efficacy, appropriate doses, and potential interactions with other therapies. In conclusion, natural aromatase inhibitory drugs are promising adjuncts in the treatment of hormone receptor-positive breast cancer. Their clinical value and safety profile, however, require additional investigation.

New insights of CYP1A in endogenous metabolism: a focus on single nucleotide polymorphisms and diseases

Cytochrome P450 1A (CYP1A), one of the major CYP subfamily in humans, not only metabolizes xenobiotics including clinical drugs and pollutants in the environment, but also mediates the biotransformation of important endogenous substances. In particular, some single nucleotide polymorphisms (SNPs) for CYP1A genes may affect the metabolic ability of endogenous substances, leading to some physiological or pathological changes in humans. This review first summarizes the metabolism of endogenous substances by CYP1A, and then introduces the research progress of CYP1A SNPs, especially the research related to human diseases. Finally, the relationship between SNPs and diseases is discussed. In addition, potential animal models for CYP1A gene editing are summarized. In conclusion, CYP1A plays an important role in maintaining the health in the body.

Estrone-3-Sulfate Stimulates the Proliferation of T47D Breast Cancer Cells Stably Transfected With the Sodium-Dependent Organic Anion Transporter SOAT (SLC10A6)

Estrogens play a pivotal role in the development and proliferation of hormone-dependent breast cancer. Apart from free estrogens, which can directly activate the estrogen receptor (ER) of tumor cells, sulfo-conjugated steroids, which maintain high plasma concentrations even after menopause, first have to be imported into tumor cells by carrier-mediated uptake and then can be cleaved by the steroid sulfatase to finally activate ERs and cell proliferation. In the present study, expression of the sodium-dependent organic anion transporter SOAT was analyzed in breast cancer and its role for hormone-dependent proliferation of T47D breast cancer cells was elucidated. The SOAT protein was localized to the ductal epithelium of the mammary gland by immunohistochemistry. SOAT showed high expression in different pathologies of the breast with a clear ductal localization, including ductal hyperplasia, intraductal papilloma, and intraductal carcinoma. In a larger breast cancer cDNA array, SOAT mRNA expression was high in almost all adenocarcinoma specimen, but expression did not correlate with either the ER, progesterone receptor, or human epidermal growth factor receptor 2 status. Furthermore, SOAT expression did not correlate with tumor stage or grade, indicating widespread SOAT expression in breast cancer. To analyze the role of SOAT for breast cancer cell proliferation, T47D cells were stably transfected with SOAT and incubated under increasing concentrations of estrone-3-sulfate (E₁S) and estradiol at physiologically relevant concentrations. Cell proliferation was significantly increased by 10^-9 M estradiol as well as by E₁S with EC₅₀ of 2.2 nM. In contrast, T47D control cells showed 10-fold lower sensitivity to E₁S stimulation with EC₅₀ of 21.7 nM. The E₁S-stimulated proliferation of SOAT-T47D cells was blocked by the SOAT inhibitor 4-sulfooxymethylpyrene. In conclusion: The present study clearly demonstrates expression of SOAT in breast cancer tissue with ductal localization. SOAT inhibition can block the E₁S-stimulated proliferation of T47D breast cancer cells, demonstrating that SOAT is an interesting novel drug target from the group of E₁S uptake carriers for anti-proliferative breast cancer therapy.

Natural Products for the Management and Prevention of Breast Cancer

Among all types of cancer, breast cancer is one of the most challenging diseases, which is responsible for a large number of cancer related deaths. Hormonal therapy, surgery, chemotherapy, and radiotherapy have been used as treatment of breast cancer, for a very long time. Due to severe side effects and multidrug resistance, these treatment approaches become increasingly ineffective. However, adoption of complementary treatment approach can be a big solution for this situation, as it is evident that compounds derived from natural source have a great deal of anticancer activity. Natural compounds can fight against aggressiveness of breast cancer, inhibit cancerous cell proliferation, and modulate cancer related pathways. A large number of research works are now focusing on the natural and dietary compounds and trying to find out new and more effective treatment strategies for the breast cancer patients. In this review, we discussed some significant natural chemical compounds with their mechanisms of actions, which can be very effective against the breast cancer and can be more potent by their proper modifications and further clinical research. Future research focusing on the natural anti-breast-cancer agents can open a new horizon in breast cancer treatment, which will play a great role in enhancing the survival rate of breast cancer patients.

DHEA metabolites activate estrogen receptors alpha and beta

Dehydroepiandrosterone (DHEA) levels were reported to associate with increased breast cancer risk in postmenopausal women, but some carcinogen-induced rat mammary tumor studies question this claim. The purpose of this study was to determine how DHEA and its metabolites affect estrogen receptors α or β (ERα or ERβ)-regulated gene transcription and cell proliferation. In transiently transfected HEK-293 cells, androstenediol, DHEA, and DHEA-S activated ERα. In ERβ transfected HepG2 cells, androstenedione, DHEA, androstenediol, and 7-oxo DHEA stimulated reporter activity. ER antagonists ICI 182,780 (fulvestrant) and 4-hydroxytamoxifen, general P450 inhibitor miconazole, and aromatase inhibitor exemestane inhibited activation by DHEA or metabolites in transfected cells. ERβ-selective antagonist R,R-THC (R,R-cis-diethyl tetrahydrochrysene) inhibited DHEA and DHEA metabolite transcriptional activity in ERβ-transfected cells. Expression of endogenous estrogen-regulated genes: pS2, progesterone receptor, cathepsin D1, and nuclear respiratory factor-1 was increased by DHEA and its metabolites in an ER-subtype, gene, and cell-specific manner. DHEA metabolites, but not DHEA, competed with 17β-estradiol for ERα and ERβ binding and stimulated MCF-7 cell proliferation, demonstrating that DHEA metabolites interact directly with ERα and ERβin vitro, modulating estrogen target genes in vivo.

Relative imbalances in the expression of catechol-O-methyltransferase and cytochrome P450 in breast cancer tissue and their association with breast carcinoma

OBJECTIVE

To investigate the expression levels of genes encoding phase I and phase II estradiol-metabolizing enzymes, and their association with breast cancer risk in Chinese women.

METHODS

The mRNA expression levels of cytochrome P450 (CYP) 1A1, 1B1 and 3A4 and catechol-O-methyltransferase (COMT) were examined in the breast tumor tissues, matched adjacent non-tumor tissues and the tissues with benign breast disease (BBD) by fluorescent quantitative real-time PCR.

RESULTS

Compared to BBD tissue, the mRNA expression of CYP1A1, CYP1B1 and CYP3A4 significantly reduced by 81.8%, 77.5%, and 85.6%, respectively, in the breast tumor tissue and by 27.2%, 38.8%, and 51.3%, respectively, in the adjacent non-tumor tissue in average (p<0.0001). COMT mRNA was 6.9 and 6.4 fold higher in the breast tumor and match non-tumor tissue (p<0.0001) than in the BBD, respectively. The level of COMT detected in pre-menopausal group and lymph nodal stage N1-N2 group was lower than that in post-menopausal group (p=0.0292) and N0 group (p=0.0389), respectively.

CONCLUSION

Significantly deceased expression of estradiol-metabolizing enzymes might result in the excess exposure of intratumoural E2, which could be one of the important risk factors for breast cancer. Significantly elevated COMT expression suggested that COMT could play a key role in breast tumor formation.

Shu-Gan-Liang-Xue Decoction Simultaneously Down-regulates Expressions of Aromatase and Steroid Sulfatase in Estrogen Receptor Positive Breast Cancer Cells

OBJECTIVE

Estradiol (E2) plays an important role in the development of breast cancer. In postmenopausal women, the estrogen can be synthesized via aromatase (CYP19) pathway and steroid-sulfatase (STS) pathway in peripheral tissues, when the production in ovary has ceased. The objective of our study was to explore the effects of Shu-Gan-Liang-Xue Decoction (SGLXD) on the expressions of CYP19 and STS in estrogen receptor positive breast cancer MCF-7 and T47D cells.

METHODS

The effects of SGLXD on the cell viability of MCF-7 and T47D were analyzed by MTT assay. By quantitative real-time RT-PCR and Western blot, we evaluated the mRNA and protein expressions of CYP19 and STS in MCF-7 and T47D cells after SGLXD treatment.

RESULTS

By MTT assay, the cell viability rates of MCF-7 and T47D were significantly inhibited by SGLXD in a dose-dependent manner, the IC50 values were 40.07 mg/ml for MCF-7 cells and 25.62 mg/ml for T47D cells, respectively. As evidenced by real-time PCR and Western blot, the high concentrations of SGLXD significantly down-regulated the expressions of CYP19 and STS both in the transcript level and the protein level.

CONCLUSION

The results suggest that SGLXD is a potential dual aromatase-sulfatase inhibitor by simultaneously down-regulating the expressions of CYP19 and STS in MCF-7 and T47D cells.

The effect of physiological concentrations of sex hormones, insulin, and glucagon on growth of breast and prostate cells supplemented with unmodified human serum

The majority of cell culture studies have assessed the effect of hormones on cancer cell growth using media supplemented with charcoal-treated fetal bovine serum (CTS). We aimed to determine whether using a system more reflective of the human condition by changing the charcoal-treated serum to an untreated pooled human serum (PHS) resulted in the same hormone responses in breast and prostate cell lines. MCF-7 breast cancer, MCF-10A non-transformed breast, and LNCaP prostate cancer cell lines supplemented with PHS were treated with high and low physiological concentrations of six hormones (17β-estradiol, dehydroepiandosterone (DHEA), dihydrotestosterone (DHT), testosterone, insulin, and glucagon). Cell growth was measured after 72 h of incubation. All hormones stimulated growth of MCF-7 cells (p < 0.05). MCF-10A cell growth was inhibited by DHEA, DHT, and testosterone (p < 0.05), unaffected by 17β-estradiol and glucagon, and stimulated by insulin (p < 0.05). LNCaP cell growth was stimulated by the highest concentration of DHEA and DHT (p < 0.05) and inhibited by the highest concentration of 17β-estradiol (p < 0.05), while insulin and testosterone, had no effect. Overall, PHS lowered the magnitude of the effect of hormones on cell growth in comparison to CTS. Due to the presence of all serum constituents, our model represents a more appropriate physiological environment for determining the effect of hormones on cancer cell growth. Further studies are required to determine the mechanisms by which added hormones interact with the constituents of untreated human serum.

Genetic Polymorphisms of the CYP19A1 Gene and Breast Cancer Survival

The CYP19A1 protein (aromatase) plays a critical role in estrogen biosynthesis and thus may be related to the progression of breast cancer. We examined the association between CYP19A1 genetic polymorphisms and breast cancer survival in a cohort of 1,136 patients who were recruited as part of a population-based case-control study in Shanghai, China from 1996 to 1998 and who has donated a DNA sample to the study. Patients were followed for cancer recurrence and mortality through July 2005. Nineteen haplotype tagging single-nucleotide polymorphisms (SNP) in the CYP19A1 gene were evaluated. For each of the five SNPs located in haplotype block 2, patients homozygous for the minor alleles had a reduced 5-year disease-free survival rate compared with those carrying the major allele. The age-adjusted hazard ratios (HR) and 95% confidence intervals (95% CI) were 1.5 (1.1-2.1), 2.1 (1.2-3.6), 1.5 (1.1-2.0), 1.4 (1.0-2.0), and 1.4 (1.0-2.0) for hCV1664178, rs12900137, rs730154, rs936306, and rs1902586, respectively. Haplotype analyses showed that the haplotype CCCTA (all minor alleles of the five SNPs in block 2) was associated with decreased disease-free survival (HR, 1.9; 95% CI, 1.1-3.3). The nonsynonymous SNP, rs700519 (Arg264Cys), located in haplotype block 4, was also associated with breast cancer survival. The age-adjusted HR for the Cys/Cys (T/T) genotype was 2.2 (95% CI, 1.2-4.1) for overall survival and 2.1 (95% CI, 1.1-3.9) for disease-free survival, compared with those carrying the Arg (C) allele. These results suggest that polymorphisms in the CYP19A1 gene may have effects on breast cancer prognosis.

Effects of 5 alpha reductase inhibitors on androgen-dependent human prostatic carcinoma cells

PURPOSE

To investigate the effects of MK906, a selective 5 alpha reductase (5alphaR) type 2 (5alphaR2) inhibitor, and of MK386, a specific 5alphaR1 inhibitor, on the cellular proliferation of androgen-dependent human prostatic cancer (PCa) cells in cultures of cells derived from bioptic and surgical tissues.

METHODS

In this study we tested the effects of MK906 and MK386 in 30 cultures derived from PCa, 6 from PIN and 10 from benign prostatic hyperplasia specimens.

RESULTS

Prostate primary cultures under short-term conditions (with <4 subcultures) represent a mixture of epithelial and stromal cells. Epithelial cells require testosterone (T) for optimal growth, but were not able to grow in the presence of T under long-term conditions even if DHT was able to induce cellular proliferation to a similar extent in both conditions, suggesting that 5alphaR can be lost in long-term cultures. Therefore, our studies were performed under short-term conditions. Both 5alphaR inhibitors decreased cell proliferation significantly and dose-dependently in all the samples tested. MK906 was more efficient than MK386 in 7 out of 10 cultures derived from BPH tissues, in 4 out of 6 cultures derived from PIN and in 18 out of 30 cultures derived from PCa. In 3 out of 10 BPH, in 2 out of 6 PIN and in 5 out of 30 PCa-derived cultures, both inhibitors presented similar efficacy, whereas in 1 out of 10 BPH and 7 out of 30 PCa-derived cultures MK386 was more efficient than MK906. In addition, MK386 was more efficient than MK906 in 4 out of 15 non-metastatic PCa and 2 out of 7 metastatic PCa-derived cultures.

CONCLUSIONS

Considering that 5alphaR1 (responsible primarily for androgenic catabolism) is mostly expressed in epithelial cells and that 5alphaR2 (responsible for local DHT synthesis and release) is expressed in the stromal cells (which provides several paracrine growth factors and DHT itself to the epithelial cells), our experiments suggest that the inhibition of both 5alphaR1 and 5alphaR2 by MK386 and MK906, respectively, may have therapeutic potential in order to reduce the growth and progression of human prostatic cancers, through the inhibition of autocrine or paracrine mechanisms involving the stromal cell compartment. In addition, some effects of 5alphaR inhibitors could be mediated by estrogens, which are synthesized by the aromatase enzyme present in the epithelial cells. These aspects could be considered in order to improve the therapeutical management of PCa and for future clinical trials.