PURPOSE: MicroRNAs are expressed abnormally in colorectal cancer (CRC) and could participate in its development. In this study we aimed to explore the molecular mechanisms of miR-503 in the genesis of CRC. METHODS: The relative expression of miR-503 and programmed cell death 4 (PDCD4) tumor suppressor in CRC tissues and cell lines were detected by qRT-PCR and Western blot. Cell migration and cell invasion were assessed by transwell assay. Moreover, the confirmation of the direct target of miR-503 in CRC was performed by luciferase reporter assay. RESULTS: The expression of miR-503 was increased remarkably in CRC, while PDCD4 decreased. Moreover, PDCD4 was verified as a specific target of miR-503 in CRC and it could reverse the effect of miR-503 on CRC cells. Furthermore, the abnormal expression of miR-503 played an important role in regulating of the development of CRC cells. In addition, PDCD4 protein expression and miR-503 mRNA expression were negatively correlated in CRC tissues. CONCLUSION: The inhibitory effect of miR-503 in CRC was realized by the upregulation of PDCD4, suggesting that miR-503/PDCD4 axis might play a critical role in CRC and could possibly be a therapeutic target.
PURPOSE: MicroRNAs are expressed abnormally in colorectal cancer (CRC) and could participate in its development. In this study we aimed to explore the molecular mechanisms of miR-503 in the genesis of CRC. METHODS: The relative expression of miR-503 and programmed cell death 4 (PDCD4) tumor suppressor in CRC tissues and cell lines were detected by qRT-PCR and Western blot. Cell migration and cell invasion were assessed by transwell assay. Moreover, the confirmation of the direct target of miR-503 in CRC was performed by luciferase reporter assay. RESULTS: The expression of miR-503 was increased remarkably in CRC, while PDCD4 decreased. Moreover, PDCD4 was verified as a specific target of miR-503 in CRC and it could reverse the effect of miR-503 on CRC cells. Furthermore, the abnormal expression of miR-503 played an important role in regulating of the development of CRC cells. In addition, PDCD4 protein expression and miR-503 mRNA expression were negatively correlated in CRC tissues. CONCLUSION: The inhibitory effect of miR-503 in CRC was realized by the upregulation of PDCD4, suggesting that miR-503/PDCD4 axis might play a critical role in CRC and could possibly be a therapeutic target.