Molecular characterization and potential therapeutic roles of miR125a in HER-2 positive gastric cancer.

Introduction: miR-125a-3p could have a role in gastric cancer by targeting HER2. This study aimed to investigate the expression pattern of miR-125a-3p, identify the expression level of its target gene in gastric carcinoma, and test its effect in HER-2 positive gastric carcinoma cells. Materials and Methods: The levels of miR-125a-3p in both cancer and noncancer tissues were measured by using Quantitative real-time polymerase chain in 70 gastric carcinomas. Immunohistochemical study was used to measure the expression of HER2 protein in these carcinomas. In addition, the level of expression of this miRNA is correlated to different pathological and clinical parameters. The effects of miR-125a-3p alone and in combination with 5-FU (fluorouracil) on the growth of HER2 positive (NUGC4) and HER2 negative (ECC10) gastric carcinoma cells were also analyzed by in vitro studies. Results: Most gastric cancer tissues samples showed downregulation of miR-125a-3p (84%) when compared to their noncancer tissues. Significant correlations of downregulation of miR-125a-3p with cancer recurrence and pathological staging of gastric carcinoma (P = 0. 02 and 0.02, respectively) were noted. HER2 protein expression correlated significantly and inversely with miR-125a-3p expression (P < 0.05). A reduction in cell growth rate was noted significantly in miR-125a-3p transfected gastric carcinoma cells when 5-FU was added to them in comparison to other control cells (P < 0.01). When both gastric carcinoma cell lines were transfected with miR-125a-3p, a significantly higher growth inhibition percentage in HER2 positive (NUGC4) cell line was seen in comparison to the HER2 negative (ECC10) cells (P < 0.01). Conclusion: miR-125a-3p plays a significant role in the pathogenesis of gastric carcinoma. Therapeutic transfection of miR-125a-3p in HER2 positive gastric cancer cells resulted in reduced cell proliferation and potentiate the effect of 5-FU.

The tumour suppressor effects and regulation of cancer stem cells by macrophage migration inhibitory factor targeted miR-451 in colon cancer.

BACKGROUND: This study aimed to investigate the impact of miR-451 on the biological behaviours of colon cancer cells along with its targets interactions. METHOD: The levels of miR-451 were tested in colon cancer cell lines (SW480 and SW48). Multiple functional and immunological assays were performed to analyse miR-451 induced growth changes in-vitro and downstream effects on target proteins. RESULTS: Overexpression of miR-451 in colon cancer cells led to reduced cell proliferation, increased apoptosis and decrease accumulation of the cells at the G0/G1 phase of the cell cycle. In addition, a significant increase in the number of the cells was noted in the G2-M phase of cell cycle. Moreover, miR-451 reduced the expression of Oct-4, Sox-2 and Snail indicating its role in stem cell and epithelial-mesenchymal transition (EMT) regulation. An inverse correlation between miR-451 and macrophage migration inhibitory protein (MIF) protein expression occurred in colon cancer cells. Furthermore, restoration the level of miR-451 in colon cancer cells inhibits tumour spheres formation. CONCLUSION: miR-451 has tumour suppressor effects in vitro, which can inhibit the cancer-related signalling pathways in colon cancer.

GAEC1 mutations and copy number aberration is associated with biological aggressiveness of colorectal cancer.

GAEC1 (gene amplified in oesophageal cancer 1) is a transforming oncogene with tumorigenic potential observed in both oesophageal squamous cell carcinoma and colorectal cancer. Nonetheless, there has been a lack of study done on this gene to understand how this gene exert its oncogenic properties in cancer. This study aims to identify novel mutation sites in GAEC1. To do so, seventy-nine matched colorectal cancers were tested for GAEC1 mutation via Sanger sequencing. The mutations noted were investigated for the correlations with the clinicopathological parameters of the patients with the cancer. Additionally, GAEC1 copy number aberration (CNA), mRNA and protein expression were determined with the use of droplet digital (dd) polymerase chain reaction (PCR), real-time PCR and Western blot (confirmed with immunofluorescence analysis). GAEC1 mutation was noted in 8.8% (n = 7/79) of the cancer tissues including one missense mutation, four loss of heterozygosity (LOH) and two substitutions. These mutations were significantly associated with cancer perforation (p = 0.021). GAEC1 mutation is frequently associated with increased GAEC1 protein expression. Nevertheless, GAEC1 mRNA and protein are only weakly associated. Taken together, GAEC1 mutation affects GAEC1 expression and is associated with poorer clinical outcomes. This further strengthens the role of GAEC1 as an oncogene.

Role of miR-193a in Cancer: Complexity and Factors Control the Pattern of its Expression.

BACKGROUND: There is emerging data suggesting that the non-coding RNA (microRNA 193a or miR-193a) plays key roles in different types of cancers. OBJECTIVE: This review aims to investigate the functional significance of miR-193a in different cancers according to the information of literature. METHOD: All the literature concerning miR-193a in cancer in PubMed are analysed. RESULTS: Several studies proved the association of miR-193a expression patterns with cancer's stages, grades, response to the chemotherapy and even patient survival. Also, miR-193a can be used to differentiate some types of cancer. In cancer, miR-193a can act as a tumour suppressor gene or as an oncogene. Till now, several genetic factors (MAX, RXR α, XB130, P63, P73, AEG-1, HIFs, EGFR, Drosha, DGCR8, Dicer) and epigenetic factors (DNA methylation and long non-coding RNAs) were predicted to control miR-193a expression. They have fundamental effects on its biological behaviour in different types of cancers. CONCLUSION: miR-193a has significant roles in cancer and can be targeted in the future for cancer therapy by better understanding of the factors that control its biological behaviour.

Expression of GAEC1 mRNA and protein and its association with clinical and pathological parameters of patients with colorectal adenocarcinoma.

AIM: GAEC1 (Gene amplified in esophageal cancer 1) is an oncogene with key regulatory roles in the pathogenesis of oesophageal and colorectal carcinomas. The aim of this study was to investigate expression profiles and clinicopathological significance of GAEC1 mRNA and protein in patients with colorectal carcinomas. METHOD: Matched cancer and non-cancer fresh frozen tissues were prospectively collected from 80 patients diagnosed with colorectal adenocarcinoma (39 men and 41 women). The tissues were sectioned for RNA extraction and cDNA conversion and quantified by a real-time polymerase chain reaction. GAEC1 protein expression was analysed by immunohistochemistry using a custom made GAEC1 antibody. RESULT: GAEC1 mRNA was upregulated in majority (52%, n=42/80) of the colorectal carcinomas when compared to the matched non-neoplastic tissues. High expression of GAEC1 mRNA as correlated with patients of younger age (p=0.008), with lower grade carcinoma (p=0.028), presence of synchronous adenocarcinomas (p=0.034) and without any associated adenomas (p=0.047). In addition, patients with high GAEC1 mRNA overexpression had a shorter survival time. Furthermore, high GAEC1 protein expression was noted among patients having perforated colorectal carcinoma (p=0.04). CONCLUSION: The high expression of GAEC1 mRNA/protein as well as its correlation with multiple clinicopathological characteristics in patients with colorectal carcinoma strongly suggests that GAEC1 is a key regulator in the initiation of colorectal carcinogenesis.

Clinical and biological significance of miR-193a-3p targeted KRAS in colorectal cancer pathogenesis.

This study was to investigate the expression pattern, mechanisms and clinicopathological implications of miR-193a-3p in colorectal cancer. Fresh-frozen tissues from 70 matched colorectal adenocarciomas and the adjacent non-neoplastic mucosae were prospectively collected. Two colorectal cancer cell lines (SW480 and SW48) and a non-neoplastic colon cell line (FHC) were also used. The expression levels of miR193a-3p in the cells and tissues were measured by quantitative real-time polymerase chain reaction. The expression of KRAS protein as a predicted downstream target for miR-193a was studied by immunohistochemistry. Restoration of the miR-193a level in the cell lines by permanent transfection was achieved and multiple functional and immunological assays were performed to analyze the functions of miR-193a in vitro. Down-regulation of miR-193a-3p was noted in 70% of the colorectal cancer tissues when compared to non-neoplastic colorectal tissues. In addition, down-regulation of miR-193a was significantly correlated with carcinoma of early stages (P<.05). Significant inverse correlation between miR-193a-3p and its target KRAS protein was determined (P<.05). Overexpression of miR-193a in colon cancer cells resulted in reduced cell proliferation, increased apoptosis, induced significant changes in cell cycle events and decreased the expression of epithelial-mesenchymal transition marker TWIST. This study confirms the tumor suppressor roles of miR-193a-3p, its downstream target affinity to KRAS and clinical significance in patients with colorectal adenocarcinoma.

Novel FAM134B mutations and their clinicopathological significance in colorectal cancer.

FAM134B is a putative tumour suppressor gene and no mutations in FAM134B have been reported in colorectal cancer (CRC) to date. This study aims to identify FAM134B mutation sites and the clinicopathological significance of the gene in patients with CRC. Eighty-eight colorectal cancers were studied for FAM134B mutations by Sanger sequencing. The mutations in these cancers were then tested for correlations with the clinical and pathological parameters of the studied cancers. In addition, mRNA and protein expression of FAM134B in colorectal cancers was examined by polymerase chain reaction, Western blots, and immunofluorescence analysis. FAM134B mutation was noted in 46.5% (41/88) of patients with CRC. Thirty-one novel potentially pathogenic mutations were noted in coding and intronic regions of FAM134B in CRC, the majority of which were single-nucleotide substitutions. Of the 31 mutations, eight novel frameshift mutations showed potential to cause non-sense-mediated mRNA decay (NMD) in computational analysis. In addition, FAM134B mutations were associated with various clinical and pathological variables, including sex of the patients, presence of metachronous cancer, size, T staging, presence of distant metastases, and positivity of microsatellite instability (MSI) in the cancer (p < 0.05). FAM134B mRNA and protein expression was decreased in FAM134B mutated cancers. To conclude, FAM134B mutation is common in colorectal cancer. The association of the mutation of this gene with adverse clinical and pathological parameters is congruent with the tumour suppressive properties of the gene.

Expression pattern of miR-451 and its target MIF (macrophage migration inhibitory factor) in colorectal cancer.

AIMS: To investigate the expression pattern of microRNA-451 (miR-451) in patients with colorectal carcinoma and correlate with the expression of its target gene MIF (macrophage migration inhibitory factor). METHODS: Matched cancer and non-cancer fresh frozen tissues were prospectively collected from 70 patients (35 men and 35 women) who underwent resection of colorectal adenocarcinoma. These tissues collected were extracted for miR and complementary DNA conversion. Then, miR-451 expressions in these tissues were measured by quantitative real-time PCR. The expression was correlated with clinical and pathological parameters of these patients. In addition, paraffin blocks of 10 colorectal carcinomas with lowest expression of miR-451 were used for the study of MIF protein expression by immunohistochemistry. RESULTS: miR-451 was downregulated in majority of the colorectal cancer tissues when compared with their matched normal tissues (84.3%, n=59/70). Downregulation of miR-451 correlates significantly with presence of coexisting adenoma (91.4%, p=0.025). In addition, persistence of cancer or cancer recurrence after surgery showed significant correlation with downregulation of miR-451 (80% vs 0%; p=0.028). There is no significant correlation between miR-451 expression and age, gender of the patients as well as size, grades, pathological stages, presence of lymphovascular permeation, perineural invasion and microsatellite instability status of the colorectal carcinoma (p>0.05). Majority of the cases (80%) with low expression of miR-451 showed high levels of MIF protein expression confirming the inverse relationship between miR-451 and MIF expressions. CONCLUSIONS: The results showed that miR-451 could play a role in development and progression of colorectal cancer and likely by targeting MIF.

Modulatory roles of microRNAs in the regulation of different signalling pathways in large bowel cancer stem cells.

There are emerging data to suggest that microRNAs (miRNAs) have significant roles in regulating the function of normal cells and cancer stem cells (CSCs). This review aims to analyse the roles of miRNAs in the regulation of colon CSCs through their interaction with various signalling pathways. Studies showed a large number of miRNAs that are reported to be deregulated in colon CSCs. However, few of the studies available were able to outline the function of miRNAs in colon CSCs and uncover their signalling pathways. From those miRNAs, which are better described, miR-21 followed by miR-34, miR-200 and miR-215 are the most reported miRNAs to have roles in colon CSC regulation. In particular, miRNAs have been reported to regulate the stemness features of colon CSCs mainly via Wnt/B-catenin and Notch signalling pathways. Additionally, miRNAs have been reported to act on processes involving CSCs through cell cycle regulation genes and epithelial-mesenchymal transition. The relative paucity of data available on the significance of miRNAs in CSCs means that new studies will be of great importance to determine their roles and to identify the signalling pathways through which they operate. Such studies may in future guide further research to target these genes for more effective cancer treatment. miRNAs were shown to regulate the function of cancer stem cells in large bowel cancer by targeting a few key signalling pathways in cells.