Elucidating the role of 17β hydroxysteroid dehydrogenase type 14 in normal physiology and in breast cancer

Oestrogens play key roles in the development of the majority of breast tumours, a fact that has been exploited successfully in treating breast cancer with tamoxifen, which is a selective oestrogen receptor modulator. In post-menopausal women, oestrogens are synthesised in peripheral hormone-target tissues from adrenally derived precursors. Important in the peripheral fine-tuning of sex hormone levels are the 17β hydroxysteroid dehydrogenases (17βHSDs). These enzymes catalyse the oxidation/reduction of carbon 17β of androgens and oestrogens. Upon receptor binding, the 17β-hydroxy conformation of androgens and oestrogens (testosterone and oestradiol) triggers a greater biological response than the corresponding keto-conformation of the steroids (androstenedione and oestrone), and the 17βHSD enzymes are therefore important mediators in pre-receptor regulation of sex hormone action. Breast tumours differ substantially with regards to molecular and/or biochemical signatures and thus clinical courses and response to treatment. Predictive factors, which aim to foretell the response of a patient to a specific therapeutic intervention, are therefore important tools for individualisation of breast cancer therapy. This thesis focuses on 17βHSD14, which is one such proposed marker, aiming to learn more of properties of the enzyme in breast cancer as well as in normal physiology. We found that high 17βHSD14 levels were correlated with clinical outcome in two separate subsets of breast tumour materials from trials evaluating adjuvant tamoxifen therapy. Striving to understand the underlying mechanisms, immunohistochemical 17βHSD14 expression patterns were analysed in a large number of human tissues using an in-house generated and validated antibody. The 17βHSD14 protein was expressed in several classical steroidogenic tissues such as breast, ovary and testis which supports idea of 17βHSD14 being an actor in sex steroid interconversion. Furthermore, using a radio-high pressure liquid chromatography method, cultured cells transiently expressing HSD17B14 were found to oxidise both oestradiol and testosterone to their less potent metabolites oestrone and androstenedione respectively. The evaluation of a mouse model lacking Hsd17b14 revealed a phenotype with impaired mammary gland branching and hepatic vacuolisation which could further suggest a role for 17βHSD14 in oestrogen regulation. Although other mechanisms of the enzyme cannot be ruled out, we suggest that 17βHSD14 relevance in tamoxifen-treated breast cancer is related to oestradiol-lowering properties of the enzyme which potentiate the anti-proliferative effects of tamoxifen. Translating into the clinical setting, patients with oestrogen receptor positive tumours expressing low levels of oestradiol-oxidising enzymes such as 17βHSD14 would likely receive more clinical benefit from alternative treatments to tamoxifen such as aromatase inhibitors or in the future possibly inhibitors of reductive 17βHSD-enzymes

Elucidating

Linköping University Medical Dissertation No. 133

Progesterone and levonorgestrel regulate expression of 17 beta HSD-enzymes in progesterone receptor positive breast cancer cell line T47D

The use of combined hormone replacement therapy (HAT) with oestrogens and progestins in postmenopausal women has been associated with an increased risk for developing breast cancer. The reasons are not fully understood, but influence of HRT on endogenous conversion of female sex hormones may be involved. The expression of 17 beta hydroxysteroid dehydrogenases (17 beta HSD), which are enzymes catalysing the conversion between more or less potent oestrogens, may partly be regulated by progestins. The breast cancer cell lines T47D, MCF7 and ZR75-1 were treated with progesterone, medroxyprogesterone acetate (MPA) or levonorgestrel for 48 and 72 h at 10(-7) and 10(-9) M to investigate influence on 17 beta HSD1, 17 beta HSD2 and 17 beta HSD5 mRNA expression measured by real time PCR. The expression of 17 beta HSD1 increased in progesterone and levonorgestrel treated T47D cells (48 h 10(-7) M P = 0.002; P andlt; 0.001) and 17 beta HSD5 increased after progesterone treatment (48 h 10(-7) M P = 0.003), whereas the expression of 17 beta HSD2 decreased after the (48 h 10(-7) M P = 0.003; P andlt; 0.001). Similar, but less prominent effects were seen in MCF7 and ZR75-1. The progestin effects on 17 beta HSD-expression were lost when T47D cells were co-treated with progestins and the progesterone receptor (PgR) inhibitor mifprestone. We show that both reductive (17 beta HSD1 and 17 beta HSD5) and oxidative (17 beta HSD2) members of the 17 beta HSD-family are under control of progesterone and progestins in breast cancer cell lines. This is most clear in T47D cells which have high PgR expression. 17 beta HSD-enzymes are important players in the regulation of sex steroids locally in breast tumours and tumoural expression of various 17 beta HSD-enzymes have prognostic and treatment predictive relevance. We propose a mechanism for increased breast cancer risk after HRT in which hormone replacement affects the expression of 17 beta HSD-enzymes, favouring the expression of reductive enzymes, which in turn could increase levels of bioactive and mitogenic estrogens in local tissue, e.g. breast tissue.Funding Agencies|Cancer and allergy foundation||Hedlunds foundation||Gosta Miltons foundation||Olle Engkvist Byggmastare foundation||Percy Falks Foundation||Cancer Foundation of Ostergotland||</p

Content management system

Manis izveidotā satura pārvaldības sistēma ir paredzēta informācijas apkopošanai, noformēšanai un ievietošanai internetā. Sistēma veidota tā, lai šīs sistēmas administratoriem, informāciju būtu gan ērti ievietot, gan arī pārvaldīt, kā arī, lai ievietotā informācija, pēc tam būtu viegli un ērti pārskatāma šīs sistēmas tīmekļa vietnes lietotājiem. Lai spētu nodemonstrēt manis veidotās satura pārvaldības sistēmas pielietojumu, pēc pasūtījuma izveidoju tīmekļa vietni „vitalikristali.lv”, kura balstās uz šo satura pārvaldības sistēmu. Tīmekļa vietne ir veidota, lai sistēmas lietotājiem tā būtu ērta un vizuāli draudzīga. Šīs tīmekļa vietnes galvenais uzdevums ir informēt tās lietotājus par veikala „Valērija Vitāli Kristāli” esošajiem piedāvājumiem, kuru skaits katru dienu mainās, kas padara šo satura pārvaldības sistēmu par labu risinājumu šīs tīmekļa vietnes pārvaldīšanai.Content management system is made with the purpose of fast and easy information compilation, formating and posting online. System is made, so that the system administrators could easily post and edit the given information and also so that the information posted would always be easily accessible by the content management systems website users. To demonstrate the system, which I have created. I also made a website “vitalikristali.lv”, which functions, are mostly based on this content management system. The website is made, so that it would be convenient to use, and also easy to look at visually. The purpose of the website is to inform its users about the offers of the store “Valērija Vitāli Kristāli”. The offers can change daily, which makes this content management system a good fit for this websites management

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Expression patterns of 17β hydroxysteroid dehydrogenase 14 in human tissue

Expression Patterns of 17β-Hydroxysteroid Dehydrogenase 14 in Human Tissues

17βHSD enzymes catalyze the stereospecific oxidation/reduction at carbon 17β of androgens and estrogens, and are important players in intracrine sex hormone synthesis. The biological relevance of 17βHSD14, first named retSDR3, is largely unknown. We generated and validated an antibody targeting the 17βHSD14 antigen and used this for immunohistochemical evaluation of expression patterns in 33 healthy human tissues. Furthermore, sex steroid conversional activity in HSD17B14 overexpressing HEK293 and MCF10A cells was investigated by assessing interconversion products of estrone, estradiol, androstenedione, testosterone, and dehydroepiandrosterone. Immunohistochemical staining patterns of 17βHSD14 with the enzyme being primarily expressed in glandular epithelial tissue reveal an enzyme with possible implications in the secretion or conversion of externally derived compounds. A role for 17βHSD14 in sex steroid metabolism is supported by the finding that 17HSD14 oxidizes both estradiol and testosterone into less bioactive steroid metabolites estrone and androstenedione, respectively

Expression Patterns of 17β-Hydroxysteroid Dehydrogenase 14 in Human Tissues

17βHSD enzymes catalyze the stereospecific oxidation/reduction at carbon 17β of androgens and estrogens, and are important players in intracrine sex hormone synthesis. The biological relevance of 17βHSD14, first named retSDR3, is largely unknown. We generated and validated an antibody targeting the 17βHSD14 antigen and used this for immunohistochemical evaluation of expression patterns in 33 healthy human tissues. Furthermore, sex steroid conversional activity in HSD17B14 overexpressing HEK293 and MCF10A cells was investigated by assessing interconversion products of estrone, estradiol, androstenedione, testosterone, and dehydroepiandrosterone. Immunohistochemical staining patterns of 17βHSD14 with the enzyme being primarily expressed in glandular epithelial tissue reveal an enzyme with possible implications in the secretion or conversion of externally derived compounds. A role for 17βHSD14 in sex steroid metabolism is supported by the finding that 17HSD14 oxidizes both estradiol and testosterone into less bioactive steroid metabolites estrone and androstenedione, respectively

C-X-C ligand 10 and C-X-C receptor 3 status can predict tamoxifen treatment response in breast cancer patients

To investigate the expression levels of CXCL10 and CXCR3 in tumors from breast cancer patients randomized to adjuvant tamoxifen treatment or no endocrine treatment, in order to further study the connection to prognosis and prediction of tamoxifen treatment outcome. Immunohistochemistry on tissue microarrays from 912 breast cancer patients randomized to tamoxifen or no endocrine treatment. CXCR3 status was found to be a prognostic tool in predicting distant recurrence, as well as reduced breast cancer-specific survival. In patients with estrogen receptor (ER)-positive tumors, tumors with strong CXCL10 levels had improved effect of tamoxifen treatment in terms of local recurrence-free survival [risk ratio (RR) 0.46 (95 % CI 0.25-0.85, P = 0.01)] compared with patients with tumors expressing weak CXCL10 expression. Further, patients with ER-positive tumors with strong CXCR3 expression had an improved effect of tamoxifen in terms of breast cancer-specific survival [RR 0.34 (95 % CI 0.19-0.62, P less than 0.001)] compared with the group with weak CXCR3 levels [RR 1.33 (95 % CI 0.38-4.79, P = 0.65)]. We show here for the first time that CXCL10 and CXCR3 expression are both predictors of favorable outcome in patients treated with tamoxifen

C-X-C ligand 10 and C-X-C receptor 3 status can predict tamoxifen treatment response in breast cancer patients

To investigate the expression levels of CXCL10 and CXCR3 in tumors from breast cancer patients randomized to adjuvant tamoxifen treatment or no endocrine treatment, in order to further study the connection to prognosis and prediction of tamoxifen treatment outcome. Immunohistochemistry on tissue microarrays from 912 breast cancer patients randomized to tamoxifen or no endocrine treatment. CXCR3 status was found to be a prognostic tool in predicting distant recurrence, as well as reduced breast cancer-specific survival. In patients with estrogen receptor (ER)-positive tumors, tumors with strong CXCL10 levels had improved effect of tamoxifen treatment in terms of local recurrence-free survival [risk ratio (RR) 0.46 (95 % CI 0.25-0.85, P = 0.01)] compared with patients with tumors expressing weak CXCL10 expression. Further, patients with ER-positive tumors with strong CXCR3 expression had an improved effect of tamoxifen in terms of breast cancer-specific survival [RR 0.34 (95 % CI 0.19-0.62, P less than 0.001)] compared with the group with weak CXCR3 levels [RR 1.33 (95 % CI 0.38-4.79, P = 0.65)]. We show here for the first time that CXCL10 and CXCR3 expression are both predictors of favorable outcome in patients treated with tamoxifen