ABSTRACT
BACKGROUND: RBP-J is involved in number of cellular processes. However, the potential mechanisms of RBP-J on colorectal cancer (CRC) development have not been clearly defined. In this study, we aimed to investigate the role and molecular mechanism of RBP-J in CRC. METHODS: The expression levels of RBP-J and Tiam1 in CRC tissues and cells were evaluated by RT-qPCR or western blot. RBP-J was knocked down with sh-RBP-J or overexpressed by pcDNA3.1-RBP-J in CRC cells. Cell proliferation, migration and invasion abilities were analyzed by MTT, wound healing, and transwell assay, respectively. CHIP-qPCR, RIP and dual luciferase reporter assays were performed to confirm the interaction between miR-182-5p and RBP-J or Tiam1. Expression levels of p-p38 MAPK, p38 MAPK, Slug-1, Twist1 and MMP-9 were analyzed by western blot. G-LISA test was used to detect Rac1 activity. RESULTS: Our results showed that the expression of RBP-J and Tiam1 was significantly up-regulated in CRC tissues and cells. RBP-J overexpression promoted proliferation, migration and invasion of CRC cells. Moreover, RBP-J was found to directly target miR-182-5p promoter and positively regulate the Tiam1/Rac1/p38 MAPK signaling pathway in CRC cells. It was also proved that miR-182-5p can bind Tiam1 directly. Furthermore, experiments revealed that RBP-J could promote CRC cell proliferation, migration and invasion via miR-182-5p-mediated Tiam1/Rac1/p38 MAPK axis. In addition, knockdown of RBP-J reduced tumor growth and metastasis in CRC mice. CONCLUSION: RBP-J regulates CRC cell growth and metastasis through miR-182-5p mediated Tiam1/Rac1/p38 MAPK signaling pathway, implying potential novel therapeutic targets for CRC patients.
Subject(s)
Colorectal Neoplasms , Immunoglobulin J Recombination Signal Sequence-Binding Protein/metabolism , MicroRNAs , Animals , Cell Cycle , Cell Proliferation/genetics , Colorectal Neoplasms/pathology , Humans , Mice , MicroRNAs/genetics , MicroRNAs/metabolism , T-Lymphoma Invasion and Metastasis-inducing Protein 1/metabolism , p38 Mitogen-Activated Protein Kinases/metabolism , rac1 GTP-Binding Protein/metabolismABSTRACT
Colorectal cancer (CRC) is one of the most lethal human cancers all over the world. Moreover, it ranks fourth for cancer-related deaths among males. Although many efforts have been made to cure CRC, the effect remains limited. It has been reported that lncRNA five prime to Xist (FTX) was upregulated in CRC. However, the mechanism by which lncRNA FTX regulates the progression of CRC remains largely unknown. In this study, qRT-PCR was performed to detect the expression of FTX, miR-590-5p and Recombination signal binding protein for immunoglobulin kappa J region (RBPJ) in CRC tissues or cells. Protein expression in cells was measured by western blot. MTT assay was used to test the cell viability. Moreover, transwell was performed to examine the cell migration and invasion. Luciferase report assay was performed to verify the relation between miR-590-5p and FTX or RBPJ. It was found that FTX was upregulated in CRC tissues and cells. Knockdown of FTX or overexpression of miR-590-5p can inhibit the proliferation, migration, and invasion of CRC cells. Besides, silencing of FTX could inhibit the expression of migration and invasion-related proteins in CRC cells. Meanwhile, miR-590-5p was the target of FTX, and RBPJ was the direct target of miR-590-5p. Inhibition of miR-590-5p could reverse the inhibitory effect of FTX on the progression of CRC. These findings suggested that knockdown of FTX could inhibit the tumorigenesis of CRC in vitro, which may serve as a potential novel strategy for treatment of CRC.
