ABSTRACT
Infection with Helicobacter pylori is important in the development and progression of gastric cancer. However, the mechanisms that regulate this activation in gastric tumors remain elusive. CACUL1 has been cloned and identified as a novel gene that is expressed in many types of cancer and is involved in cell cycle regulation and tumor growth. The current study aimed to examine the expression of CACUL1 in gastric cancer samples and analyze its correlation with H. pylori infection. We found that CACUL1 was highly expressed in gastric cancer tissues and negatively correlated with gastric cancer differentiation and TNM stage. In addition, CACUL1 expression was high in H. pylori-infected tissues compared with H. pylori non-infected tissue. We found that H. pylori could up-regulate CACUL1 expression through activating protein 1. The up-regulation of CACUL1 expression could promote matrix metalloproteinase 9 and Slug expression to increase invasion and metastasis of tumor cells. These results suggested that H. pylori-triggered CACUL1 production occurred in an activating protein 1-dependent manner and regulated matrix metalloproteinase 9 and Slug expression to affect the invasion and metastasis of tumor cells. Therefore, CACUL1 is a potential therapeutic target for the treatment of aggressive gastric cancer.
Subject(s)
Cullin Proteins/genetics , Helicobacter pylori/physiology , Stomach Neoplasms/microbiology , Stomach Neoplasms/pathology , Transcription Factor AP-1/metabolism , Up-Regulation , Adult , Aged , Aged, 80 and over , Animals , Anthracenes/pharmacology , Cell Line, Tumor , Cullin Proteins/metabolism , Curcumin/pharmacology , Female , Gastric Mucosa/metabolism , Gene Expression Regulation, Neoplastic , Humans , Male , Matrix Metalloproteinase 9/metabolism , Mice , Middle Aged , Neoplasm Invasiveness , Neoplasm Metastasis , Phosphorylation , Promoter Regions, Genetic/genetics , Proto-Oncogene Proteins c-fos/metabolism , Stomach/pathology , Stomach Neoplasms/enzymology , Stomach Neoplasms/genetics , Transcriptional Activation/genetics , Young AdultABSTRACT
There is evidence indicating that bile acid is a promoter of colorectal cancer. Deoxycholic acid modifies apoptosis and proliferation by affecting intracellular signaling and gene expression. We are interested in revealing the relationship between deregulated miRNAs and deoxycholic acid in colorectal cancer development. We found that miR-199a-5p was expressed at a low level in human primary colonic epithelial cells treated with deoxycholic acid compared with control, and miR-199a-5p was significantly down-regulated in colorectal cancer tissues. The miR-199a-5p expression in colorectal cancer cells led to the suppression of tumor cell growth, migration and invasion. We further identified CAC1, a cell cycle-related protein expressed in colorectal cancer, as a miR-199a-5p target. We demonstrated that CAC1 is over-expressed in malignant tumors, and cellular CAC1 depletion resulted in cancer growth suppression. HCT-8 cells transfected with a miR-199a-5p mimic or inhibitor had a decrease or increase in CAC1 protein levels, respectively. The results of the luciferase reporter gene analysis demonstrated that CAC1 was a direct miR-199a-5p target. The high miR-199a-5p expression and low CAC1 protein expression reverse the tumor cell drug resistance. We conclude that miR-199a-5p can regulate CAC1 and function as a tumor suppressor in colorectal cancer. Therefore, the potential roles of deoxycholic acid in carcinogenesis are to decrease miR-199a-5p expression and/or increase the expression of CAC1, which contributes to tumorigenesis in patients with CRC. These findings suggest that miR-199a-5p is a useful therapeutic target for colorectal cancer.
Subject(s)
Adenocarcinoma/metabolism , Colorectal Neoplasms/metabolism , Cullin Proteins/genetics , Deoxycholic Acid/physiology , MicroRNAs/metabolism , RNA Interference , 3' Untranslated Regions , Adenocarcinoma/drug therapy , Adenocarcinoma/mortality , Adenocarcinoma/pathology , Adult , Aged , Aged, 80 and over , Animals , Antibiotics, Antineoplastic/pharmacology , Apoptosis , Base Sequence , Cell Line, Tumor , Cell Movement , Cell Proliferation , Cell Survival , Colorectal Neoplasms/drug therapy , Colorectal Neoplasms/mortality , Colorectal Neoplasms/pathology , Cullin Proteins/metabolism , Deoxycholic Acid/pharmacology , Doxorubicin/pharmacology , Drug Resistance, Multiple , Drug Resistance, Neoplasm , Female , Gene Expression Regulation, Neoplastic , Gene Knockdown Techniques , Humans , Kaplan-Meier Estimate , Male , Mice , Mice, Inbred BALB C , Mice, Nude , MicroRNAs/genetics , Middle Aged , Transcriptome , Tumor Burden , Xenograft Model Antitumor AssaysABSTRACT
PURPOSE: Pleiotrophin (PTN) is an important developmental secretory cytokine expressed in many types of cancer and involved in angiogenesis and tumor growth; however, the significance of PTN expression in colorectal cancer (CRC) has not been established. METHODS: Immunohistochemistry, western blot, and enzyme-linked immunosorbent assay were used to detect PTN expression in CRC patients. The relationship between PTN expression and clinicopathological characteristics and survival time was statistically analyzed, and the relationship between PTN and vascular endothelial growth factor (VEGF) in tumor angiogenesis was further analyzed. RESULTS: Of CRC tissues, 74.70% (62/83) stained positive, with a strong positive ratio of 60.24% (50/83). The expression of PTN in CRC tissues was much higher than in normal colorectal tissues. PTN serum levels in CRC patients (mean = 254.59 ± 261.76 pg/ml) were significantly higher than those of normal volunteers (mean = 115.23 ± 79.53 pg/ml; p < 0.001). PTN expression was related to CRC differentiation and TNM staging. High level of PTN is a predictor of a poor prognosis and high expression of PTN is accompanied by high expression of VEGF in CRC patients. Investigation of the relationship between PTN and VEGF revealed that PTN, through the PTN/RPTPß/ζ signaling pathway, increased tyrosine phosphorylation of ß-catenin, leading to an increase in VEGF. CONCLUSIONS: Our study identifies PTN as an essential growth factor for CRC. PTN promotes VEGF expression and cooperates with VEGF in promoting CRC angiogenesis. PTN could serve as a prognostic factor for this cancer. Considering that PTN shows very limited expression in normal tissue, it may represent an attractive new target for CRC therapy.
