Endometriosis and breast cancer are sex hormone dependent diseases characterised by the local production of high levels of 17β-oestradiol. The relationship between prostaglandins and sex steroid hormones is one of the focal questions in endometriosis, breast cancer and other sex steroid hormone related disorders. Therefore, the main hypothesis was that the aldo-keto reductase (AKR) 1C isoenzymes are responsible for controlling the availability of 17β-oestradiol, progesterone and prostaglandins in the microenvironment of the endometrium, and surrounding adipose tissues of endometriotic lesions and breast tumours. This was investigated using quantitative real-time polymerase chain reaction (PCR) for measuring the gene expression of AKR1C1-3 enzymes, and prostaglandin E (1-4) and F receptors in the endometrium, and surrounding adipose tissues of endometriotic lesions and breast tumours. This was then followed by investigating the role of one of the AKR1C enzymes - AKR1C3 - by inhibiting its catalysis using bimatoprost, followed by using PGE2 as one of the main candidates acting as a transcription factor for upregulating the expression of AKR1C3 which in turn upregulates the production of the local 17β-oestradiol. The gene expression of AKR1C1 was significantly higher in endometriotic lesions compared to eutopic endometrium of endometriosis patients. However, there was no significant difference in the gene expression of AKR1C (1-3) enzymes in the surrounding adipose tissues of endometriotic lesions between patients with or without endometriosis. Also, there was no significant difference in the gene expression of AKR1C (1-3) enzymes in the breast adipose tissues of patients with breast tumours, regardless of the oestrogen or progesterone receptor status. The gene expression of prostaglandin E (EP) receptor subtype 3 was significantly higher in the endometriotic lesions compared to eutopic endometrium of endometriosis patients. In the omental adipose tissue, there was no significant difference in the gene expression of EP1-4 and FP receptors between endometriosis and non-endometriosis patients. In the breast adipose tissue, there was also no significant difference in the gene expression of EP1-4 and FP receptors in patients with breast cancer regardless of the oestrogen or progesterone receptor status. The inhibitory constant (Ki) of bimatoprost was determined using oestrone as a substrate: Ki = 2.9µM and αKi = 0.7µM. Bimatoprost also significantly inhibited the production of 17β-oestradiol and inhibited the production of 9α,11β PGF2 in a dose dependent manner in the human endometrial cells. The effect of PGE2 on the expression of AKR1C1 and AKR1C3 was assessed in the human endometrial cells. The EP4 receptor agonist, L-902688, increased the gene expression of AKR1C1 and AKR1C3. Despite gene expression elevation, L-902688 did not increase the production of 17β-oestradiol. In conclusion, the results were contradictory and highlighted the need for further investigation into the relationship between prostaglandins and sex steroid hormones in the microenvironment of the endometrium, and surrounding adipose tissues of endometriotic lesions and breast tumours.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:706276 |
| Date | January 2017 |
| Creators | Zarroug, Osman Hamza |
| Contributors | Marshall, Kay ; Nicolaou, Anna |
| Publisher | University of Manchester |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | https://www.research.manchester.ac.uk/portal/en/theses/the-roles-of-prostaglandin-e2-prostaglandin-f2alpha-and-aldoketo-reductase-1c-isoenzymes-in-endometriosis-and-breast-cancer(08db7cb3-7222-4513-b13b-cc3474c1ca2b).html |
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