BXL-628, a vitamin D receptor agonist effective in benign prostatic hyperplasia treatment, prevents RhoA activation and inhibits RhoA/Rho kinase signaling in rat and human bladder.
BACKGROUND
BXL-628 is a calcitriol analog shown to decrease prostate growth in preclinical and clinical studies. BPH symptoms are generated not only by prostate overgrowth but also by bladder overactivity, resulting from an increased RhoA/Rho-kinase signaling. Because bladder smooth muscle cells express VDR, we studied effects of BXL-628 on this pathway.


METHODS
RhoA and Rho-kinase gene expression and functional activity were studied in rat and human bladder smooth muscle by real-time RT-PCR, immuno-kinase assays, western blot analysis, confocal microscopy, in vitro contractility, and cell migration.


RESULTS
In bladder smooth muscle, carbachol responsiveness was delayed and Rho-kinase activity reduced by BXL-628 treatment because of impaired RhoA membrane translocation and activation. Accordingly, RhoA-mediated biological functions, such as cell migration and cytoskeleton remodeling were also inhibited by BXL-628.


CONCLUSIONS
BXL-628 inhibits RhoA/Rho-kinase signaling, a calcium sensitizing pathway, suggesting its possible clinical use in the treatment of altered bladder contractility often associated with BPH-induced lower urinary tract symptoms.
Morelli
Annamaria
A
Andrology Unit, Department of Clinical Physiopathology, Center for Research, Transfer and High Education DENOTHE, Univesity of Florence, Florence, Italy.
Vignozzi
Linda
L
Filippi
Sandra
S
Vannelli
Gabriella Barbara
GB
Ambrosini
Stefano
S
Mancina
Rosa
R
Crescioli
Clara
C
Donati
Silvia
S
Fibbi
Benedetta
B
Colli
Enrico
E
Adorini
Luciano
L
Maggi
Mario
M
D000818:Animals; D002117:Calcitriol / Q000031:analogs & derivatives* / Q000494:pharmacology; D002118:Calcium / Q000097:blood; D002217:Carbachol / Q000037:antagonists & inhibitors / Q000494:pharmacology; D002465:Cell Movement / Q000187:drug effects; D018679:Cholinergic Agonists / Q000494:pharmacology; D004347:Drug Interactions; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D066298:In Vitro Techniques; D047908:Intracellular Signaling Peptides and Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D032389:Myocytes, Smooth Muscle / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000737:chemistry / Q000235:genetics; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D017207:Rats, Sprague-Dawley; D018167:Receptors, Calcitriol / Q000819:agonists*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D001743:Urinary Bladder / Q000187:drug effects* / Q000201:enzymology*; D054460:rho-Associated Kinases; D020742:rhoA GTP-Binding Protein / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*
C487049:BXL628; D018679:Cholinergic Agonists; D047908:Intracellular Signaling Peptides and Proteins; D012333:RNA, Messenger; D018167:Receptors, Calcitriol; D002217:Carbachol; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases; D020742:rhoA GTP-Binding Protein; D002117:Calcitriol; D002118:Calcium