Effect of Sprouty2 Downregulation on MicroRNA Expression Profile in HCT116 Colon Cancer Cells

Sprouty proteins are evolutionarily conserved modulators of mitogen-activated protein kinase pathway. Sprouty2 appears to function as a tumor suppressor in cancers, whereas we reported earlier that Sprouty2 functions as an oncogene in colorectal cancer. To further understand the oncogenic potential of Sprouty2 in the colon, microRNA expression profile of colon cancer cells was investigated. Sprouty2 suppression in HCT116 colon cancer cells significantly increased MicroRNA 194-5p. Sprouty2 dependent regulation of microRNA194-5p and its biological targets were studied further for their tumor suppressive actions in reducing epithelial-mesenchymal transition in colorectal cancer. Sprouty2 knockdown was performed by infecting HCT116 cells with three different lentivirus expressing shRNAs against human Sprouty2 mRNA and a control non targeted non-silencing shRNA (Sprouty2 MISSION shRNA Lentiviral Transduction Particles; TRCN 0000007522, TRCN 0000231589, TRCN 0000231588 and a non-targeted shRNA control from Sigma) following lentiviral transduction protocols provided by Sigma. Due to the random integration of the lentivirus into the host genome, varying levels of Sprouty2 gene knockdown was expected in puromycin resistant colonies. Three colonies in triplicate that demonstrated highest to lowest level of Sprouty2 suppression, as assessed by western blotting, were selected. RNA samples from these colonies and one from non-targeted shRNA expressing colony were prepared for microRNA expression profile analysis. Pooled RNA samples from each group were shipped to Exiqon for microRNA profiling based on miRCURY LNATM array technology.