Anti-tumor effect of Shu-Gan-Liang-Xue decoction in breast cancer is related to the inhibition of aromatase and steroid sulfatase expression

ETHNOPHARMACOLOGICAL RELEVANCE

Shu-Gan-Liang-Xue Decoction (SGLXD), a traditional Chinese herbal formula used to ameliorate the hot flushes in breast cancer patients, was reported to have anti-tumor effect on breast cancer. Estrogen plays a critical role in the genesis and evolution of breast cancer. Aromatase and steroid sulfatase (STS) are key estrogen synthesis enzymes that predominantly contribute to the high local hormone concentrations. The present study was to evaluate the anti-tumor effect of SGLXD on estrogen receptor (ER) positive breast cancer cell line ZR-75-1, and to investigate its underlying mechanisms both in vitro and in vivo.

MATERIALS AND METHODS

The anti-tumor activity of SGLXD in vitro was investigated using the MTT assay. The in vivo anti-tumor effect of SGLXD was evaluated in non-ovariectomized and ovariectomized athymic nude mice. The effect of SGLXD on enzymatic activity of aromatase and STS was examined using the dual-luciferase reporter (DLR) based on bioluminescent measurements. Aromatase and STS protein level were assessed using Western blot assay.

RESULTS

SGLXD showed dose-dependent inhibitory effect on the proliferation of ZR-75-1 cells with IC50 value of 3.40 mg/mL. It also suppressed the stimulating effect on cell proliferation of testosterone and estrogen sulfates (E1S). Oral administration of 6 g/kg of SGLXD for 25 days resulted in a reduction in tumor volume in non-ovariectomized and ovariectomized nude mice. The bioluminescent measurements confirmed that SGLXD has a dual-inhibitory effect on the activity of aromatase and STS. Western blot assay demonstrated that the treatment of SGLXD resulted in a decrease in aromatase and STS protein levels both in vitro and in vivo.

CONCLUSION

Our results suggested that SGLXD showed anti-tumor effect on breast cancer cells both in vitro and in vivo. The anti-tumor activity of SGLXD is related to inhibition of aromatase and STS via decreasing their expression. SGLXD may be considered as a novel treatment for ER positive breast cancer.

17β-Estradiol and estradiol fatty acyl esters and estrogen-converting enzyme expression in adipose tissue in obese men and women

CONTEXT

Obesity is associated with increased circulating 17β-estradiol (E₂), but less is known about E₂ concentrations in adipose tissue. In addition to E₂, adipose tissue synthesizes E₂ fatty acyl esters (E₂-FAE).

OBJECTIVE

The aim was to compare estrogen concentrations and expression of estrogen-converting enzymes in adipose tissue between severely obese men and women.

DESIGN AND SETTING

Tissue samples were obtained during elective surgery in University Central Hospital in the years 2008 through 2011.

PATIENTS

We studied 14 men and 22 premenopausal women undergoing bariatric surgery and 10 control women operated for nonmalignant reasons.

INTERVENTIONS

Paired samples were taken from abdominal sc and visceral adipose tissue and serum and analyzed for E₂ and E₂-FAE by fluoroimmunoassay and liquid chromatography-tandem mass spectrometry. mRNA expression of genes was analyzed by quantitative PCR.

RESULTS

Compared with men, E₂ levels in sc adipose tissue in obese women were higher, along with higher relative mRNA expression of steroid sulfatase and 17β-hydroxysteroid dehydrogenases 1, 7, and 12. In men, E₂-FAE concentrations in adipose tissue were similar to E₂ but in women significantly lower compared with E₂. Adipose tissue E₂-FAE and serum E₂-FAE levels correlated positively in obese subjects. Serum E₂ did not significantly correlate with E₂ concentration or mRNA expression of genes in adipose tissue in obese men or women.

CONCLUSIONS

The production of E₂ by the large adipose mass was not reflected by increased circulating E₂ concentrations in severely obese men or women. However, adipose tissue may contribute to concentrations of serum E₂-FAE.

The expression of the human steroid sulfatase-encoding gene is driven by alternative first exons

We have analyzed steroid sulfatase (STS) gene transcription in 10 human tissues: ovary, adrenal cortex, uterus, thyroid, liver, pancreas, colon, mammary gland, dermal papilla of the hair follicle, and peripheral mononuclear leukocytes. Overall, six different promoters were found to drive STS expression, giving rise to transcripts with unique first exons that were labeled 0a, 0b, 0c, 1a, 1c, and 1d, of which the last two and 0c are newly reported. All of them, except exon 1d, vary in length owing to the occurrence of multiple transcriptional start sites. While placental exon 1a is partially coding, the other five first exons are all untranslated. Three of these (0a, 0b, and 0c) are spliced to the common partially coding exon 1b, whereas the other two (1c and 1d) are spliced to the coding exon 2, which occurs in all transcripts. Whatever the ATG actually used, the differences are restricted to the signal peptide which is post-transcriptionally cleaved. Transcripts with exons 0a and 0b have the broadest tissue distribution, occurring, in 6 out of the 12 tissues so far investigated, while the other first exons are restricted to one or two tissues. The proximal promoter of each first exon was devoid of TATA box or initiator element and lacked consensus elements for transcription factors related to steroidogenesis, suggesting that regulatory sequences are probably placed at greater distance. In conclusion, the regulation of STS transcription appears to be more complex than previously thought, suggesting that this enzyme plays a substantial role in intercellular integration.

Steroid sulfatase in breast carcinoma and change of serum estrogens levels after operation

Fifty-four breast carcinomas were studied for the expression of steroid sulfatase (STS) by immunohistochemistry. Correlations between the expression of STS and clinical parameters were determined. Concentrations of serum estrone (E1), estrone sulfate (E1S), estradiol (E2) and estradiol sulfate (E2S) in 12 postmenopausal patients with STS positive tumor were measured by radioimmunoassay. Positive expression of STS was obtained in 72% of tumors. The incidence of STS positive tumor was significantly more frequent in postmenopausal patients (p = 0.01). In our postmenopausal patients, serum E1, E1S, E2, E2S and E2S levels in STS high score group were decreased postoperatively, and those in both STS high and low score group were stabilized after operation. Results from this study suggest STS in breast carcinoma may play an important enzyme of the intratumoral estrogen synthesis in postmenopausal women, and it would be interesting that locally produced STS might be closely related to the control of estrogens environment in breast carcinoma.

The role of STS and OATP-B mRNA expression in predicting the clinical outcome in human breast cancer

BACKGROUND

Steroid sulfatase (STS) is the enzyme responsible for hydrolysing biologically inactive estrogen sulfates to active estrogens. Therefore it plays a significant role in supporting the growth of hormone-dependent tumours of the breast, endometrium and prostate. OATP-B is a member of a family of membrane transporter proteins that regulates the uptake of steroid sulfates through cell membranes. Our objective was to determine, using quantitative PCRA whether the mRNA expression levels from these genes were positively correlated with clinical outcome in human breast cancer. This is the first study in the literature to examine the relationship between STS and OATP-B in human breast cancer and to investigate the potential prognostic value of OATP-B.

MATERIALS AND METHODS

A total of 153 samples (120 tumour tissues and 33 normal breast tissues) were analysed. The levels of transcription of STS and OATP-B were determined using real-time quantitative PCR and normalized against cytokeratin 19. The levels of expression were analysed against tumour's stage, grade, nodal status, local relapse, distant metastasis, ERalpha, ERbeta and HER1-4 receptor status and survival over a 10 year follow up period.

RESULTS

The levels of STS mRNA were significantly higher in malignant samples (p=0.031) and in node positive disease (p=0.0222). STS mRNA expression increased with increasing tumour grade but this did not reach statistical significance. A significant increase was also noted in levels correlating with tumour stage when stages TNM1 and TNM2, TNM2 and TNM3, and TNM3 and TNM4 (p=0.00001, 0.0017 and 0.02, respectively) were compared. Furthermore, STS expression levels positively correlated with progression of disease, as levels were significantly higher in samples from patients who developed metastasis, local recurrence, or died of breast cancer when compared to those who were disease free for >10 years (p=0.0036). No significant correlation was found between the levels of STS expression and ERalpha/ERbeta/ status. The levels positively correlated with HER1 and HER3 receptors. The levels of mRNA expression of OATP-B were higher in malignant tissue compared to normal tissue; this, however, did not reach statistical significance (p=0.4045). Levels were also higher in node positive disease (p=0.0672). Expression levels increased with increasing tumour grade and this became statistically significant when comparing grade 1 to 2, and grade 2 to 3 (p=0.0271 and 0.0289, respectively). An increase in levels correlating with TNM tumour staging was also observed; this, however, did not reach statistical significance. There was no significant correlation between OATP-B expression levels and clinical progression of breast cancer. No correlation was found between STS and OATP-B expression levels.

CONCLUSION

This study demonstrates a compelling trend for STS transcription levels to be higher in cancer tissues and in patients who developed progressive disease. OATP-B expression levels correlated with the grade and stage of the disease, but not with the clinical outcome. These results suggest that STS mRNA has a significant potential as an important predictor of clinical outcome in patients with breast cancer.

Strong expression of steroid sulfatase in human cumulus cells in patients with endometriosis

OBJECTIVE

To investigate the localization and expression of steroid sulfatase (STS) in cumulus cells obtained from subjects with and without endometriosis.

DESIGN

Case-control study.

SETTING

In vitro fertilization program at the Showa University School of Medicine.

PATIENT(S)

Cumulus cells (142 samples) were obtained from 49 patients for whom IVF was indicated. Some of these samples were taken from cases complicated by endometriosis (35 samples), polycystic ovary syndrome (PCOS; 16 samples), or latent hyperprolactinemia (16 samples).

INTERVENTION(S)

Immunohistochemical staining for STS. Measurement of STS mRNA expression by real-time polymerase chain reaction (PCR).

MAIN OUTCOME MEASURE(S)

Expression of STS mRNA and localization of STS.

RESULT(S)

Steroid sulfatase was localized in the cytoplasm of the cumulus cells, and expression of STS mRNA was observed. The expression level of STS mRNA from patients with endometriosis was significantly higher (11.8-fold) than that of patients without endometriosis.

CONCLUSION(S)

These results suggest a local steroidal regulation mechanism in cumulus cells. Although the physiological role of STS in cumulus cells remains unclear, STS may be involved in the quality of eggs in patients with endometriosis.