EVALUATION OF MULTIDRUG RESISTANCE PROTEINS TYPE 4 AND 5 IN CONTROLLING INTRACELLULAR LEVELS OF cAMP AND cGMP AND CELL PROLIFERATION IN PROSTATIC CELLS.

• Grant number: 24/00216-8
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• Start date: July 01, 2024
• End date: June 30, 2025
• Field of knowledge: Biological Sciences - Pharmacology - Autonomic Pharmacology
• Principal Investigator: Fabíola Taufic Monica Iglesias
• Grantee: Gabriela Reolon Passos
• Supervisor: Davide Calebiro
• Host Institution: Faculdade de Ciências Médicas (FCM). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Institution abroad: University of Birmingham, England
• Associated to the scholarship: 22/11621-5 - Evaluation of reactive oxygen species on the epithelial and stromal prostate cell lines viability and prostate fragments of undergoing prostate resection patient reactivity., BP.PD

Abstract

The enlargement in volume, size, and tone of the prostate gives rise to benign prostatic hyperplasia (BPH), a condition characterized by the compression of the prostatic urethra, leading to lower urinary tract symptoms (LUTS). In the healthy prostate, the regulation of intracellular levels of cAMP and cGMP primarily involves the activation of the beta-adrenoceptor and the nitric oxide (NO)-soluble guanylyl cyclase (sGC) pathway, respectively. Additionally, adenosine, via its receptors A2A and A2B, along with other mediators such as prostanoids, plays a secondary role in modulating cAMP levels. Although phosphodiesterases (PDEs) have been extensively investigated as the primary enzymes responsible for second messenger s degradation, several studies have highlighted a relevant role for the multidrug resistance proteins type 4 (MRP4) and 5 (MRP5). These proteins play an active role in pumping cAMP and/or cGMP out of the cytosol, introducing an additional layer to these complex regulatory mechanisms. MRPs belong to the ATP-binding cassette superfamily of transporters. The expression and physiological activity of MRP4 have been explored across various human tissues and cells. Notably, MRP5 has been identified for its high affinity to cGMP. Immunohistochemistry studies have unveiled the localization of MRP5 in vascular smooth muscle cells, cardiomyocytes, and vascular endothelial cells. MK-571, initially acknowledged as a cysteinyl leukotriene receptor antagonist, is a pharmacological tool commonly used to assess the role of MRP4 and MRP5, acting as an inhibitor. Other tools are also used to assess this pathway such as Ceefourin-1 and Probenecid. The physiological role of MRPs in the lower urinary tract has received less attention compared to platelets, cancer cells, and the cardiovascular system. However, previous work indicates that MRP5 is present in the smooth muscle cells of the ureter, urethra, bladder, and corpus cavernosum. Our research groups have been demonstrated that cAMP and cGMP levels are lower in bladder, prostate, urethra and corpus cavernosum of obese mice and middle-aged rat and that MRP4/5 inhibition with MK571 increases cAMP/cGMP levels in those tissues. These findings suggest a potential role for MRP4/5 in urogenital tract disorders and LUTS secondary to BPH and ED. To our knowledge, there is no research in the literature evaluating the role of MRP4 and MRP5 in non-cancerous human prostate and prostate cell lines. Based on our primary findings, we hypothesize that the inhibition of MRP4 and MRP5 plays a direct role in in regulating cAMP and cGMP levels in healthy and diseased prostate; Specifically: 1) MRP4 and MRP5 expression levels could generate an imbalance between the ratio of extracellular and intracellular levels of cAMP and cGMP; 2) The imbalance between extra and intracellular cAMP/cGMP levels could be a trigger for cell proliferation; 3) the overexpression of MRP in prostate could enhance BPH. Thus, in this proposal we aim to evaluate the function of cyclic nucleotides transporters (specifically MRP4 and MPR5) in human prostate cell lines. Cell lines with MRP4/5 silencing/overexpression (PNT1A, RPWE-1 and BPH-1) will be used to evaluate the intra and extracellular levels of cAMP and cGMP, as well as whether MK571 could improve the intracellular levels of theses second messengers in these cell lines. These studies could provide new insights into the function of MRPs in prostate and their involvement in in BPH. This, in turn, could contribute to the development of more effective pharmacological therapies for this condition.