| Summary: | 碩士 === 國立臺灣大學 === 生命科學系 === 104 === Calreticulin (CRT) is a multifunctional chaperone protein, which mainly locates on the membrane of endoplasmic reticulum (ER). Previous studies suggested that expression of CRT is up-regulated in various types of cancers and promotes tumorigenesis and metastasis through stabilizing fucosyltransferase 1 (FUT-1) mRNA in bladder cancer cell line J82. Besides, overexpressed CRT up-regulates the expression of Vascular Endothelial Growth Factor A (VEGF-A), which is widely considered as a major regulator for angiogenesis in different cancer models. In this study, we therefore attempt to clarify whether CRT regulates VEGF-A mRNA stability. We observed that depletion of CRT results in a significant decrease of mRNA stability of VEGF-A following by suppression of both VEGF-A RNA and protein levels in bladder cancer, gastric cancer, and prostate cancer. Further, dual luciferase assay was performed to demonstrate that CRT recognized AU-Rich Element (ARE) of VEGF-A in the 3’UTR to regulate stability of VEGF-A mRNA. Indeed, the results of biotin pull-down assay showed that CRT combines to ARE region of VEGF-A to form RNA-protein complex which was confirmed by additional liquid chromatography–mass spectrometry (LC-MS/MS). In conclusion, this study provides a novel machanism that CRT forms mRNA-protein complex with ARE at the 3’UTR of VEGF-A to increase VEGF-A mRNA stability in distinct cancer cell lines, which CRT enhances cancer progression and endothelial cells angiogenesis for metastasis.
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