ABSTRACT
Fibroblast growth factor receptor-like-1 (FGFRL1) is important to cell motility and links with tumorigenic potential in various types of cancers. To investigate the biological function and underlying mechanism of FGFRL1 in rectal adenocarcinoma, we conducted this study. TCGA and Oncomine databases were used to analyze FGFRL1 expression and its association with clinical characteristics or overall survival (OS) in rectal adenocarcinoma patients. siRNA strategy was implemented to knockdown FGFRL1 expression in rectal adenocarcinoma cells. CCK8, colony formation, wound healing, and transwell assays were implemented to measure cell behaviors. qRT-PCR and western blot were utilized to identify mRNA and protein expression levels. FGFRL1 was significantly increased in rectal adenocarcinoma tissue samples, either colon or rectum. High-regulation of FGFRL1 expression induced poorer outcome of rectal adenocarcinoma patients. Downregulation of FGFRL1 inhibited the proliferation, colony formation, migration, and invasion of SW837 cells. The MAPK pathway-related proteins, phosphorylation of MEK and ERK, were also decreased after si-FGFRL1 transfection. These findings demonstrated that FGFRL1, acting as a potential inducator, may promote the progression of rectal adenocarcinoma via activating the MAPK signaling pathway.
Subject(s)
Adenocarcinoma/drug therapy , Molecular Targeted Therapy , Receptor, Fibroblast Growth Factor, Type 5/metabolism , Rectal Neoplasms/drug therapy , Adenocarcinoma/pathology , Cell Line, Tumor , Cell Movement/genetics , Cell Proliferation , Down-Regulation/genetics , Female , Gene Expression Regulation, Neoplastic , Gene Knockdown Techniques , Humans , MAP Kinase Signaling System , Male , Middle Aged , Neoplasm Invasiveness , Prognosis , Receptor, Fibroblast Growth Factor, Type 5/genetics , Rectal Neoplasms/pathology , Tumor Stem Cell AssayABSTRACT
The progression of distant metastasis cascade is a multistep and complicated process, frequently leading to a poor prognosis in cancer patients. Recently, growing evidence has indicated that deregulation of microRNAs (miRNAs) contributes to tumorigenesis and tumor progression in colorectal cancer (CRC). In the present study, by comparing the miRNA expression profiles of CRC tissues and corresponding hepatic metastasis tissues, we established the downregulation of miR-199b in CRC metastasis tissues. The decrease in miR-199b expression was significantly correlated to late TNM stage and distant metastasis. Moreover, Kaplan-Meier curves showed that CRC patients with high expression level of miR-199b had a longer median survival. Functional assays results indicated that the restoration of miR-199b considerably reduced cell invasion and migration in vitro and in vivo, and increased the sensitivity to 5-FU and oxaliplatin. Further dual-luciferase reporter gene assays revealed that SIRT1 was the direct target of miR-199b in CRC. The expression of miR-199b was inversely correlated with SIRT1 in CRC specimens. SIRT1 knockdown produced effects on biological behavior that were similar to those of miR-199b overexpression. Furthermore, through Human Tumor Metastasis PCR Array we discovered KISS1 was one of the downstream targets of SIRT1. Silencing of SIRT1 upregulated KISS1 expression by enhancing the acetylation of the transcription factor CREB. The latter was further activated via binding to the promoter of KISS1 to induce transcription. Thus, we concluded that miR-199b regulates SIRT1/CREB/KISS1 signaling pathway and might serve as a prognosis marker or a novel therapeutic target for patients with CRC.
Subject(s)
Colorectal Neoplasms/pathology , Gene Expression Regulation, Neoplastic/genetics , MicroRNAs/genetics , Neoplasm Invasiveness/genetics , Sirtuin 1/metabolism , Adult , Aged , Animals , Colorectal Neoplasms/genetics , Colorectal Neoplasms/metabolism , Cyclic AMP Response Element-Binding Protein/genetics , Cyclic AMP Response Element-Binding Protein/metabolism , Down-Regulation , Female , Heterografts , Humans , Kaplan-Meier Estimate , Kisspeptins/genetics , Kisspeptins/metabolism , Male , Mice , Mice, Inbred BALB C , Mice, Nude , MicroRNAs/metabolism , Middle Aged , Neoplasm Invasiveness/pathology , Prognosis , Sirtuin 1/geneticsABSTRACT
BACKGROUND: Recent studies have indicated the possible function of miR-217 in tumorigenesis. However, the roles of miR-217 in colorectal cancer (CRC) are still largely unknown. METHODS: We examined the expression of miR-217 and AEG-1 in 50 CRC tissues and the corresponding noncancerous tissues by qRT-PCR. The clinical significance of miR-217 was analyzed. CRC cell lines with miR-217 upregulation and AEG-1 silencing were established and the effects on tumor growth in vitro and in vivo were assessed. Dual-luciferase reporter gene assays were also performed to investigate the interaction between miR-217 and AEG-1. RESULTS: Our data demonstrated that miR-217 was significantly downregulated in 50 pairs of colorectal cancer tissues. MiR-217 expression levels were closely correlated with tumor differentiation. Moreover, decreased miR-217 expression was also associated with shorter overall survival of CRC patients. MiR-217 overexpression significantly inhibited proliferation, colony formation and invasiveness of CRC cells by promoting apoptosis and G0/G1 phase arrest. Interestingly, ectopic miR-217 expression decreased AEG-1 expression and repressed luciferase reporter activity associated with the AEG-1 3'-untranslated region (UTR). AEG-1 silencing resulted in similar biological behavior changes to those associated with miR-217 overexpression. Finally, in a nude mouse xenografted tumor model, miR-217 overexpression significantly suppressed CRC cell growth. CONCLUSIONS: Our findings suggest that miR-217 has considerable value as a prognostic marker and potential therapeutic target in CRC.
Subject(s)
Biomarkers, Tumor/biosynthesis , Cell Adhesion Molecules/biosynthesis , Colorectal Neoplasms/genetics , MicroRNAs/biosynthesis , Aged , Animals , Apoptosis/genetics , Biomarkers, Tumor/genetics , Cell Adhesion Molecules/genetics , Cell Cycle Checkpoints/genetics , Cell Line, Tumor , Cell Proliferation/genetics , Cell Transformation, Neoplastic/genetics , Colorectal Neoplasms/pathology , Female , Gene Expression Regulation, Neoplastic , Humans , Male , Membrane Proteins , Mice , MicroRNAs/genetics , Middle Aged , Neoplasm Invasiveness/genetics , Prognosis , RNA-Binding Proteins , Xenograft Model Antitumor AssaysABSTRACT
Tumor growth cascade is a complicated and multistep process with numerous obstacles. Until recently, evidences have shown the involvement of microRNAs (miRNAs) in tumorigenesis and tumor progression of various cancers, including colorectal cancer (CRC). In this study, we explored the role of miR-194 and its downstream pathway in CRC. We acquired data through miRNA microarray profiles, showing that the expression of miR-194 was significantly suppressed in CRC tissues compared with corresponding noncancerous tissues. Decreased miR-194 expression was obviously associated with tumor size and tumor differentiation, as well as TNM stage. Both Kaplan-Meier and multivariate survival analysis showed that downregulated miR-194 was associated with overall survival. Moreover, functional assays indicated that overexpression of miR-194 in CRC cell lines inhibited cell proliferation both in vitro and in vivo. In addition, using dual-luciferase reporter gene assay, we found MAP4K4 was the direct target of miR-194. Silencing of MAP4K4 resulted in similar biological behavior changes to that of overexpression of miR-194. We also observed through Human Gene Expression Array that MDM2 was one of the downstream targets of MAP4K4. Knockdown of MAP4K4 downregulated MDM2 expression through transcription factor c-Jun binding to the -1063 to -1057 bp of the promoter. These results suggest that miR-194, regulating the MAP4K4/c-Jun/MDM2 signaling pathway, might act as a tumor suppressor and serve as a novel target for CRC prevention and therapy.
