- Title
- The renin-angiotensin system in endometrial cancer
- Creator
- Riazuddin, Mohammed
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2019
- Description
- Research Doctorate - Doctor of Philosophy (PhD)
- Description
- Endometrial cancer is one of the fourth most common cancer in the developed world and its incidence is increasing rapidly. Several studies have shown that there is an upregulation of the pro-angiogenic arm of the renin angiotensin system in endometrial cancer. Endometrial cancers express both prorenin and (pro)renin receptor ((P)RR) mRNA and have significantly greater levels of these proteins than normal adjacent endometrial tissue. Prorenin acting via the (P)RR can activate both RAS dependent and independent signaling pathways. To determine the functional role of (P)RR in endometrial cancer growth, we used siRNA transfection to knock down (P)RR expression in three endometrial cancer cell lines (Ishikawa, HEC-1A and AN3CA). All three of the endometrial cancer cell lines examined (Ishikawa, HEC-1A and AN3CA) expressed (P)RR and prorenin (REN) mRNA, however levels of (P)RR and AGTR1 were much higher in Ishikawa cells. Transfection with a (P)RR siRNA resulted in knockdown of (P)RR at both gene and protein level in three cell lines. Furthermore, there was a significant reduction in endometrial cancer cell growth (proliferation and cell viability) in Ishikawa and AN3CA cells. Several studies show that (P)RR is released in a soluble form (s(P)RR) into blood and urine. We therefore hypothesized that s(P)RR could be released from endometrial cancer cells and that levels of s(P)RR in blood and uterine fluid would be elevated in women with endometrial cancer. The levels of s(P)RR were measured with a specific s(P)RR ELISA it was found that all three cell lines secrete s(P)RR into the cell culture supernatant. Also, we found that there was significant amount of s(P)RR levels in plasma samples. Therefore, we postulated that endometrial cancer growth can be inhibited by drugs that block Angiotensin (Ang) II/Ang II type 1 receptor interactions and prorenin/(P)RR mediated signaling pathways. Further we looked at the individual effects and combined effects of RAS blockers with ATP6AP2 siRNA on cell viability and cell proliferation in three endometrial cancer cell lines. There was no effect of aliskiren (a renin inhibitor) on cell viability in HEC-1A and AN3CA cell lines. Perindoprilat (an ACE inhibitor) and losartan (an AT1R receptor antagonist) had no effect on the cell viability of any cell line. Another AT1R antagonist, telmisartan, which also acts as a selective agonist of peroxisome proliferator-activated receptor gamma (PPAR-γ), did however significantly reduce the viability of the three cell lines (Ishikawa 75%, HEC-1A 50% and AN3CA 60%). The combination of telmisartan + troglitazone had a similar effect to that of telmisartan on its own. Aliskiren + perindoprilat reduced the viability of HEC-1A cells, there was no effect in Ishikawa and AN3CA cells. Conversely, the combination of (P)RR siRNA + telmisartan significantly reduced cell viability and cell proliferation in Ishikawa cells. We also looked at the effect of ovarian steroids (estrogen and progesterone) on RAS expression in two other cancer cell lines (an endometrial cancer cell line (RL-952) and a breast cancer cell line (MCF-7). Treatment with estrogen had no effect on RAS expression in RL-952 or MCF-7 cells. This study is the first to characterize the functional role of prorenin and (P)RR in endometrial cancer, and to demonstrate that drugs that inhibit the (P)RR and/the RAS pathway could reduce endometrial cancer growth. Finally, measurement of s(P)RR could be used as a biomarker for endometrial cancer detection.
- Subject
- renin-angiotensin system; endometrial cancer; prorenin receptor; (pro)renin receptor; siRNA transfection
- Identifier
- http://hdl.handle.net/1959.13/1403486
- Identifier
- uon:35178
- Rights
- Copyright 2019 Mohammed Riazuddin
- Language
- eng
- Full Text
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