Signaling pathways involved in the regulation of the GPRC5A gene in T84 cells

MORI, CONSUELO;; ANGEL GABRIEL VALDIVIESO; CLAUZURE, MARIÁNGELES; MASSIP-COPIZ, M.; SANTA COLOMA TA,

Mar del Plata

Congreso; LXIII Reunión de la Sociedad Argentina de Investigación Clínica (SAIC); 2018

(732) SIGNALING PATHWAYS INVOLVED IN THE REGULATIONOF THE GPRC5A GENE IN T84 CELLSConsuelo Mori, Angel Gabriel Valdivieso, Mariangeles Clauzure,María Macarena Massip Copiz, Tomás Santa Coloma1BIOMED-CONICET-UCAThe G protein-coupled receptor 5A (GPRC5A), also known as Retinoicacid-induced gene 3 (RAI3) or Retinoic acid-induced gene 1(RAIG1). GPRC5A was first cloned in our laboratory with the namePEG-1 (phorbol ester induced gene-1), because it was found to be a12-O-tetradecanoyl phorbol 13-acetate (TPA)-inducible gene. TPA,also called phorbol 12-myristate 13-acetate (PMA), is a small moleculedrug that activates the signal transduction enzyme protein kinaseC (PKC) by directly binding to its C1 domains. Commonly, TPAis employed as a tumor-promoting agent. GPRC5A dysregulation isassociated to diverse types of cancer in humans and it was originallyreported as a tumor suppressor in non-small cell lung carcinomaand in oral squamous cell carcinoma. In contrast, it has also beenreported that GPRC5A could act as an oncogene in breast cancer,colorectal cancer and pancreatic cancer. This dual behavior makesGPRC5A an interesting gene to study. However, little is known aboutthe function of this protein and its regulation. The aim of this workwas studying the regulation of GPRC5A in human colon cancer. Todetermine the signaling pathways involved in this regulation, T84cells (human colon adenocarcinoma cells) were stimulated with TPAfor 4 h, in presence or absence of different pathway inhibitors, andthe gene expression was analyzed by real-time PCR. PKC, PKA,MEK inhibitors and BAPTA treatment (intracellular calcium chelator)decreased significantly the GPRC5A mRNA expression. On thecontrary, the SGK1, NF-kB, JNK and P38 inhibitors increased significantlyGPRC5A mRNA levels. Interestingly, the AKT inhibitor inabsence of TPA stimulation increased significantly the GPRC5A ex-pression but did not show effect in presence of TPA. In conclusion,GPRC5A is regulated by multiple common pathways. Supported byPIP 2015-2017, PUE 22920160100129CO, and PICT-2015-1031 toAGV.