Regulation of PSCA expression by m-Numb in the stomach (904.2)

Prostate stem cell antigen (PSCA) is a GPI-anchored cell surface protein expressed in the normal epithelium of several tissues including the isthmus region of the gastric mucosa. Recently, a genome-wide association study revealed several SNPs in the PSCA-gene to be associated with gastric cancer and duodenal ulcer risk. However, the underlying regulatory mechanisms of PSCA are still unclear. Methods: Msi1-KO mice with lowered expression of m-Numb in the stomach and wild-type ICR mice were used for in vivo studies. In vitro studies were carried out with the mouse gastric epithelial cell line MGE507. Overexpression and suppression of m-Numb in MGE507 cells was achieved by transfection with lentiviral particles carrying an m-Numb expression vector and shRNA expression vector, respectively. Gene expression was analysed with qRT-PCR, and western blotting was used to measure protein levels. Results: In Msi1-KO mice, a significantly reduced expression- and protein level of PSCA was found when comparing the gastr...