Up-regulation of steroid sulphatase activity in HL60 promyelocytic cells by retinoids and 1alpha,25-dihydroxyvitamin D3.
(9/136)
HL60 promyeloid cells express both classes of oestrogen receptor (ERalpha and ERbeta). We show that hydrolysis of oestrone sulphate by steroid sulphatase is a major source of oestrone in HL60 cells, and that most of the released oestrone is not metabolized further to 17beta-oestradiol. Treatment of HL60 cells with retinoids or 1alpha,25-dihydroxyvitamin D3 increased steroid sulphatase mRNA and activity in parallel with the induction of CD11b, an early marker of myeloid differentiation that is expressed before the differentiating cells stop proliferating. Use of agonists and antagonists against retinoid receptor-alpha and retinoid receptor-X revealed that both classes of retinoid receptor can drive steroid sulphatase up-regulation. Steroid sulphatase activity fluctuates during the cell cycle, being highest around the transition from G1 to S phase. During the differentiation of HL60 cells induced by all-trans-retinoic acid or 1alpha,25-dihydroxyvitamin D3, there is increased conversion of 17beta-oestradiol into oestrone by an oxidative 17beta-hydroxysteroid dehydrogenase. Treatment of Caco-2 colon adenocarcinoma cells with all-trans-retinoic acid or 1alpha,25-dihydroxyvitamin D3 also increases 17beta-oestradiol oxidation to oestrone. An increase in local oestrone production therefore occurs in multiple cell types following treatment with retinoids and 1alpha,25-dihydroxyvitamin D3. The possible involvement of locally produced oestrogenic steroids in regulating the proliferation and differentiation of myeloid cells is discussed. (+info)
M31 and macroH2A1.2 colocalise at the pseudoautosomal region during mouse meiosis.
(10/136)
Progression through meiotic prophase is associated with dramatic changes in chromosome condensation. Two proteins that have been implicated in effecting these changes are the mammalian HP1-like protein M31 (HP1beta or MOD1) and the unusual core histone macroH2A1.2. Previous analyses of M31 and macroH2A1.2 localisation in mouse testis sections have indicated that both proteins are components of meiotic centromeric heterochromatin and of the sex body, the transcriptionally inactive domain of the X and Y chromosomes. This second observation has raised the possibility that these proteins co-operate in meiotic sex chromosome inactivation. In order to investigate the roles of M31 and macroH2A1.2 in meiosis in greater detail, we have examined their localisation patterns in surface-spread meiocytes from male and female mice. Using this approach, we report that, in addition to their previous described staining patterns, both proteins localise to a focus within the portion of the pseudoautosomal region (PAR) that contains the steroid sulphatase (Sts) gene. In light of the timing of its appearance and of its behaviour in sex-chromosomally variant mice, we suggest a role for this heterochromatin focus in preventing complete desynapsis of the terminally associated X and Y chromosomes prior to anaphase I. (+info)
Deletion pattern of the STS gene in X-linked ichthyosis in a Mexican population.
(11/136)
BACKGROUND: X-linked ichthyosis (XLI) is an inherited disorder due to steroid sulfatase deficiency (STS). Most XLI patients (>90%) have complete deletion of the STS gene and flanking sequences. The presence of low copy number repeats (G1.3 and CRI-S232) on either side of the STS gene seems to play a role in the high frequency of these interstitial deletions. In the present study, we analyzed 80 Mexican patients with XLI and complete deletion of the STS gene. MATERIALS AND METHODS: STS activity was measured in the leukocytes using 7-[(3)H]-dehydroepiandrosterone sulfate as a substrate. Amplification of the regions telomeric-DXS89, DXS996, DXS1139, DXS1130, 5' STS, 3' STS, DXS1131, DXS1133, DXS237, DXS1132, DXF22S1, DXS278, DXS1134-centromeric was performed through PCR. RESULTS: No STS activity was detected in the XLI patients (0.00 pmoles/mg protein/h). We observed 3 different patterns of deletion. The first two groups included 25 and 32 patients, respectively, in which homologous sequences were involved. These subjects showed the 5' STS deletion at the sequence DXS1139, corresponding to the probe CRI-S232A2. The group of 32 patients presented the 3' STS rupture site at the sequence DXF22S1 (probe G1.3) and the remaining 25 patients had the 3' STS breakpoint at the sequence DXS278 (probe CRI-S232B2). The third group included 23 patients with the breakpoints at several regions on either side of the STS gene. No implication of the homologous sequences were observed in this group. CONCLUSION: These data indicate that more complex mechanisms, apart from homologous recombination, are occurring in the genesis of the breakpoints of the STS gene of XLI Mexican patients. (+info)
Steroid sulfatase in the human hair follicle concentrates in the dermal papilla.
(12/136)
5 alpha-dihydrotestosterone is known to play a crucial part in the regulation of hair growth and in the development of androgenetic alopecia. 5 alpha-dihydrotestosterone is formed locally within the hair follicle from the systemic precursor testosterone by cutaneous steroid 5 alpha-reductase. Moreover, adrenal steroids such as dehydroepiandrosterone are converted to 5 alpha-dihydrotestosterone by isolated hair follicles, which may provide an additional source of intrafollicular 5 alpha-dihydrotestosterone levels. Elevated urinary dehydroepiandrosterone and serum dehydroepiandrosterone sulfate have been reported to be present in balding young men. These reports suggest that dehydroepiandrosterone sulfate may act as an important endocrine factor in the development of androgenetic alopecia. Hence the question arises whether the dehydroepiandrosterone sulfate can be metabolized within the hair follicles to yield dehydroepiandrosterone by the microsomal enzyme steroid sulfatase, and where steroid sulfatase might be localized. We therefore performed immunostaining for steroid sulfatase on human scalp biopsies as well as analysis of steroid sulfatase enzyme activity in defined compartments of human beard and occipital hair follicles ex vivo. Using both methods steroid sulfatase was primarily detected in the dermal papilla. Steroid sulfatase activity was inhibited by estrone-3-O-sulfamate, a specific inhibitor of steroid sulfatase, in a concentration-dependent way. Furthermore, we show that dermal papillae are able to utilize dehydroepiandrosterone sulfate to produce 5 alpha-dihydrotestosterone, which lends further support to the hypothesis that dehydroepiandrosterone sulfate contributes to androgenetic alopecia and that steroid sulfatase inhibitors could be novel drugs to treat androgen-dependent disorders of the hair follicle such as androgenetic alopecia or hirsutism. (+info)
The influence of inflammatory cytokines on estrogen production and cell proliferation in human breast cancer cells.
(13/136)
Estrogens play important roles in the development of breast cancer. Inflammatory cytokines such as interleukin-6 (IL-6) and interleukin-1 beta (IL-1 beta) exist at high concentrations in breast cancer tissue. Although these cytokines are thought to exert some effect on cancer growth, their precise mechanism is still unclear. In the present study, we investigated the effects of inflammatory cytokines on aromatase (Arom) and steroid sulfatase (STS), which are estrogen-producing enzymes, and cell proliferation using human breast cancer cell lines (SK-BR-3, MCF-7). IL-6 and IL-1 beta stimulated the activity of Arom and STS. Estrone sulfate (E1-S) had a stimulus effect on cell proliferation of MCF-7. Although IL-6 did not show significant effect on cell proliferation, cell proliferation was significantly increased when IL-6 and E1-S were simultaneously added to the incubation medium. This cell proliferative effect was apparently stronger than the addition of E1-S alone. Addition of IL-1 beta in the presence of E1-S also significantly enhanced cell proliferation though IL-1 beta alone did not show any effect. These results led us to the hypothesis that inflammatory cytokines such as IL-6 and IL-1 beta regulate proliferation of breast cancer cells through estrogen production by steroid-catalyzing enzymes in the tissue. (+info)
Somatic and germinal mosaicism for the steroid sulfatase gene deletion in a steroid sulfatase deficiency carrier.
(14/136)
Steroid sulfatase deficiency results in X-linked ichthyosis, an inborn error of metabolism in which the principal molecular defect is the complete deletion of the steroid sulfatase gene and flanking markers. Mosaicism for the steroid sulfatase gene has not yet been reported in X-linked ichthyosis. In this study we describe an X-linked ichthyosis patient with complete deletion of the steroid sulfatase gene and his mother with somatic and germinal mosaicism for this molecular defect. The family (X-linked ichthyosis patient, grandmother, mother, and sister) was analyzed through steroid sulfatase enzyme assay, polymerase chain reaction, DNA markers, and fluorescence in situ hybridization of the steroid sulfatase gene. Steroid sulfatase activity was undetectable in the X-linked ichthyosis patient, very low in the mother, and normal in the grandmother and sister. The X-linked ichthyosis patient showed a 2 Mb deletion of the steroid sulfatase gene and flanking regions from 5'DXS1139 to 3'DXF22S1. The mother showed one copy of the steroid sulfatase gene in 98.5% of oral cells and in 80% of leukocytes. The grandmother and sister showed two copies of the steroid sulfatase gene. The origin of the X chromosome with the deletion of the steroid sulfatase gene corresponded to the grandfather of the proband. We report the first case of somatic and germinal mosaicism of the steroid sulfatase gene in an X-linked ichthyosis carrier and propose DNA slippage as the most plausible mechanism in the genesis of this mosaicism. (+info)
CYP3A4 and CYP3A7-mediated carbamazepine 10,11-epoxidation are activated by differential endogenous steroids.
(15/136)
Recently, we reported that several endogenous steroids affect CYP3A4-mediated drug metabolism, using human adult liver microsomes as an enzyme source. Especially, carbamazepine (CBZ) 10,11-epoxidation is activated by androstenedione (AND). In the present studies, we investigated the effects of endogenous steroids on the activity of CBZ 10,11-epoxidation by expressed CYP3A4 and CYP3A7. When expressed CYP3A4 was used as an enzyme source, the addition of AND to the reaction mixture also caused a drastic increase in the activity of CBZ 10,11-epoxidase, and resulted in a change in the kinetics from sigmoid to Michaelis-Menten type. On the other hand, expressed CYP3A7-mediated CBZ 10,11-epoxidation was activated by sulfate conjugate steroids, such as pregnenolone 3-sulfate, 17alpha-hydroxypregnenolone 3-sulfate, and dehydroepiandrosterone 3-sulfate (DHEA-S), whereas the unconjugated form corresponding to these three steroids did not activate the reaction. Especially, DHEA-S was found to be a potent activator of CBZ 10,11-epoxidation by expressed CYP3A7. The kinetic character of CBZ 10,11-epoxidation by CYP3A7 is Michaelis-Menten type regardless of the presence of DHEA-S. The presence of DHEA-S caused a decrease in K(m) and increase in V(max) for CYP3A7-mediated CBZ 10,11-epoxidation, whereas DHEA-S 16alpha-hydroxylation was not affected by the coexistence of CBZ. In conclusion, CYP3A4 and CYP3A7-mediated CBZ 10,11-epoxidations are activated by different types of endogenous steroids. This is the first report regarding CYP3A7 cooperativity. (+info)
Estrogen sulfotransferase and steroid sulfatase in human breast carcinoma.
(16/136)
Estrogen sulfotransferase (EST; SULT 1E1 or STE gene) sulfonates estrogens to inactive estrogen sulfates, whereas steroid sulfatase (STS) hydrolyzes estrone sulfate to estrone. Both EST and STS have been suggested to play important roles in regulating the in situ production of estrogens in human breast carcinoma tissues. However, the expression of EST has not been examined in breast carcinoma tissues, and the biological significance of EST and STS remains unknown. Therefore, in this study, we examined the expression of EST and STS in 35 specimens of human breast carcinoma tissues using immunohistochemistry, reverse transcription-PCR (RT-PCR), and enzymatic assay. EST and STS immunoreactivity was also correlated with various clinicopathological parameters, including prognosis to examine the biological significance of these enzymes in 113 breast carcinomas. EST and STS immunoreactivity was detected in carcinoma cells and significantly associated with their mRNA levels (P = 0.0027 and 0.0158, respectively), as measured by RT/real-time PCR, and enzymatic activities (P = 0.0005 and 0.0089, respectively) in 35 breast carcinomas. In breast cancer tissues examined by laser capture microdissection/RT-PCR analyses, the mRNA for EST was localized in both carcinoma and intratumoral stromal cells, whereas that of STS was detected only in carcinoma cells. Of the 113 invasive ductal carcinomas examined in this study, EST and STS immunoreactivity was detected in 50 and 84 cases (44.2 and 74.3%), respectively. In these cases, EST immunoreactivity was inversely correlated with tumor size (P = 0.003) or lymph node status (P = 0.0027). In contrast, STS immunoreactivity was significantly correlated with tumor size (P = 0.0047). Moreover, EST immunoreactivity was significantly associated with a decreased risk of recurrence or improved prognosis by both uni (P = 0.0044, and 0.0026, respectively) and multivariate (P = 0.0429 and 0.0149, respectively) analyses. STS immunoreactivity, however, was significantly associated with an increased risk of recurrence (P = 0.0118) and worsened prognosis (P = 0.0325) by univariate analysis. Results from our present study suggest that immunoreactivities for both EST and STS are associated with their mRNA level and enzymatic activity and that EST immunoreactivity is considered to be a potent prognostic factor in human breast carcinoma. (+info)