Regulation of β-Catenin signaling by Gq class of G-proteins in colon cancer cells

Introduction and Aim: Colon cancer is one of the most common malignancies in the world. The Wnt/β-catenin signaling pathway plays a crucial role in the regulation of colon tissue regeneration and therefore, deregulation of this signaling pathway can lead to development of colon cancer. We have previously shown that heterotrimeric G proteins (especially the Gq family of these proteins) positively regulate the Wnt/β-catenin signal transduction by using two cell systems including Xenopus oocytes and human embryonic kidney 293T cells. Here, we have investigated the interaction between these two signaling pathways in colon cancer cells. Methods: The colon cancer cell lines (SW-480 and HT-29) were cultured in RPMI medium containing 10% FBS. In this research we used GP-Antagonist 2A (a specific Gq blocking peptide) and a minigene encoding a specific peptide which specifically blocks Gq signaling. Transfection of colon cancer cells with the above blockers was performed using Lipofectamine 2000. MTT, Flowcytometery and immunofluorescence microscopy experiments were performed to measure cellular physiology, β-catenin protein levels, and β-catenin cellular localization in SW-480 and HT-29 colon cancer cells. Results: The result of MTT experiments showed that treatment or expression of the cells with the Gq blockers did not significantly affect the cell viability. Flow cytometery analysis showed that the above Gq blockers can induce apaptosis in both cell lines. In addition, immunofluorescence microscopy results suggested that Gq blocking peptides can change the expression and cellular localization of the β-catenin protein. Conclution:Our preliminary results indicate that the Gq signaling could have a significant role in the regulation of the Wnt/β-catenin signaling pathway. We are currently investigating the details of the interaction between these two signaling pathways.

کلیدواژه ها:

β-catenin ، Gq ، colon cancer