"鈣網蛋白經由多腺嘌呤-尿嘧啶序列調控膀胱癌細胞J82之alpha(1,2)-岩藻醣轉移酶表達"

Abstract

Calreticulin (CRT) localizes to intracellular, cell surface and extracellular compartments and regulates a variety of diverse and important biological processes. CRT ensures proper folding of proteins and glycoproteins regulating homeostatic control of cytosolic and ER calcium levels. CRT is necessary for cell adhesion, migration and phagocytosis of apoptotic cells. CRT can be detected in urine of bladder cancer patients as a cancer marker. Higher concentration of urinary CRT tends to increase pathologic stages of tumor. Down-regulation of CRT suppresses tumor growth and metastatic capacities in human bladder cancer. Glycosylation of integrin modulates the binding strength of integrin and extracellular matrix (ECM) binding. Fucosyltransferase 1 (FUT1) expression and fucosylation of β1 integrin, catalyzed by FUT1, were down-regulated when CRT in human bladder cancer cells was knocked down (data unpublished). Suppression of FUT1 expression and fucosylation of β1 integrin may lead to modulation of tumor cell attachment and tumor malignances. Real-time PCR and mRNA degradation assays have indicated that half-life of FUT1 mRNA is much shorter in bladder cancer cells transfected with CRT-RNAi than in the control cells. These data implicated that the suppression of FUT1 expression might due to instability of FUT1 mRNA. In this IV study, we built EGFP-FUT1 3’UTR constructions with wild type adenylate-uridin rich element (ARE), mutated ARE and deleted ARE respectively. By transfecting each of these three constructions in J82 bladder cancer cells, we found that CRT plays a crucial role in modulating FUT1 mRNA stability through interacting with ARE in 3’UTR of FUT1 mRNA.