Inhibition of Multidrug Resistance Proteins by MK 571 Enhances Bladder, Prostate, and Urethra Relaxation through cAMP or cGMP Accumulation

Author(s)

Bertollotto, Gabriela Maria ^[1] ; de Oliveira, Mariana Goncalves ^[1] ; Alexandre, Eduardo Costa ^[1] ; Calmasini, Fabiano Beraldi ^[1] ; Passos, Gabriela Reolon ^[1] ; Antunes, Edson ^[1] ; Monica, Fabiola Zakia ^[1]

Affiliation

^[1] Univ Estadual Campinas, Dept Pharmacol, Fac Med Sci, Rua Alexander Fleming, BR-13083881 Campinas, SP - Brazil

• Document type: Journal article
• Source: Journal of Pharmacology and Experimental Therapeutics; v. 367, n. 1, p. 138-146, OCT 1 2018.
• Web of Science Citations: 2

Abstract

The biologic effect of cAMP and cGMP is terminated by phosphodiesterases and multidrug resistance proteins MRP4 and MRP5, which pump cyclic nucleotides out of the cell. Therefore, this study aimed to characterize the role of MRP inhibitor, MK 571 (3-{[}{[}{[}3-{[}(1E)-2-(7-chloro-2-qu inolinyl)ethenyl]phenyl]{[}{[}3-(dinnethylannino)-3-oxopropyl]thio]nneth yl]thio]propanoic acid), in the bladder, prostate, and urethra of male mice by means of functional assays, protein expression, and cyclic nucleotide quantification. The cumulative addition of MK 571 (1-30 mu M) produced only small relaxation responses (approximately 25%) in all studied tissues. In the bladder, isoprenaline/fenoterol and forskolin concentration-dependently relaxed and MK 571 (20 mu M) increased the maximal response values by 37% and 24%, respectively. When MK 571 was coincubated with fenoterol or forskolin, intracellular levels of cAMP and protein expression of phospho-vasodilator-stimulated phosphoprotein (p-VASP) Ser157 were significantly greater compared with bladders stimulated with fenoterol or forskolin alone. In the prostate and urethra, sodium nitroprusside concentration-dependently relaxed and MK 571 (20 mu M) significantly increased relaxation responses by 70% and 56%, respectively, accompanied by greater intracellular levels of cGMP and protein expression of p-VASP Ser239 in the prostate. Tadalafil and BAY 41-2272 (5-cyclopropyl-2-{[}1-{[}(2-fluorophenyl)methyl]1H-pyrazolo{[}3,4-b]pyri din-3-yl]-4-pyrinnidinannine) also relaxed the prostate and urethra, respectively, and MK 571 markedly enhanced this response. The stable analog of cGMP (8-Br-cGMP) induced concentration-dependent relaxation responses in the prostate and urethra, and MK 571 significantly increased the relaxation response. In conclusion, to our knowledge, this is the first study to show that efflux transporters are physiologically active in the bladder, prostate, and urethra to control intracellular levels of cAMP or cGMP. (AU)

• FAPESP's process: 17/15175-1 - Modulation of soluble guanylate cyclase and the intracellular levels of cyclic nucleotides in the lower urinary tract and prostate
• Grantee: Edson Antunes
• Support Opportunities: Research Projects - Thematic Grants