miRNA as markers for the diagnostic screening of colon cancer

Differential Digestive Stability of Food-Derived microRNAs: The Case of miR-30c-5p and miR-92a-3p in Polyfloral Honey

Dietary microRNAs (miRs) represent a new area in food science. Although they have been found in many foods, including honey, more research is needed about their stability and fate during digestion. Hence, this study aimed to analyze the digestive stability of two selected miRs in honey. We extracted miR-92a-3p and miR-30c-5p from pasteurized and unpasteurized forms of polyfloral honey using two different methods and kits: a column-based manual method and a phenol-free semi-automated magnetic-bead-based method. The latter option was used for the subsequent analysis of samples according to the INFOGEST static in vitro digestion protocol. Also, the honey samples were examined for exosome-like particles using dynamic light scattering. Although the expression levels of both miRs were significantly lower following intestinal digestion, we found a difference in the resilience of the miRs to gastrointestinal conditions, with miR-30c-5p being relatively stable compared to miR-92a-3p following digestion, regardless of the honey's pasteurization treatment. Moreover, there was marked heterogeneity in the extracellular vesicle profile of the pasteurized sample. We identified the presence of two broadly conserved miRs in honey: miR-92a-3p and miR-30c-5p. Despite honey exhibiting high digestibility, miR-92a-3p was less resilient than miR-30c-5p, demonstrating considerable resistance under gastrointestinal conditions. Although further research is needed, the results obtained from this study may represent a starting point for utilizing honey as a source of exogenous miRNAs for preventive strategies and more "natural" treatments.

Exploring miRNA Profiles in Colon Cancer: A Focus on miR101-3p, miR106a-5p, and miR326

Early diagnosis and prognosis of cancer progression through biomarker profiling are crucial in managing colon cancer patients. Our research aimed to investigate the expression of miR-101-3p, miR-106a-5p, and miR-326 in tumor and adjacent healthy tissues of colon cancer patients and determine their potential diagnostic utility. This study included 40 patients divided into four groups according to the TNM staging classification. MiRNA expression was analyzed using qRT-PCR. The results showed that miR-101-3p, miR-106a-5p, and miR-326 are overexpressed in adjacent healthy tissues but decrease in advanced cancer stages. MiR-106a-5p and miR-326 are strongly correlated with colon cancer severity. These findings suggest that miRNA profiling could be useful for early diagnosis and prognosis in colon cancer management.

Targeting miR-31 represses tumourigenesis and dedifferentiation of BRAFV600E-associated thyroid carcinoma

BACKGROUND

BRAFV600E is the most common genetic mutation in differentiated thyroid cancer (DTC) occurring in 60% of patients and drives malignant tumour cell phenotypes including proliferation, metastasis and immune-escape. BRAFV600E-mutated papillary thyroid cancer (PTC) also displays greatly reduced expression of thyroid differentiation markers, thus tendency to radioactive iodine (RAI) refractory and poor prognosis. Therefore, understanding the molecular mechanisms and main oncogenic events underlying BRAFV600E will guide future therapy development.

METHODS

Bioinformatics and clinical specimen analyses, genetic manipulation of BRAFV600E-induced PTC model, functional and mechanism exploration guided with transcriptomic screening, as well as systematic rescue experiments were applied to investigate miR-31 function within BRAFV600E-induced thyroid cancer development. Besides, nanoparticles carrying miR-31 antagomirs were testified to alleviate 131I iodide therapy on PTC models.

RESULTS

We identify miR-31 as a significantly increased onco-miR in BRAFV600E-associated PTC that promotes tumour progression, metastasis and RAI refractoriness via sustained Wnt/β-catenin signalling. Mechanistically, highly activated BRAF/MAPK pathway induces miR-31 expression via c-Jun-mediated transcriptional regulation across in vitro and transgenic mouse models. MiR-31 in turn facilitates β-catenin stabilisation via directly repressing tumour suppressors CEBPA and DACH1, which direct the expression of multiple essential Wnt/β-catenin pathway inhibitors. Genetic functional assays showed that thyroid-specific knockout of miR-31 inhibited BRAFV600E-induced PTC progression, and strikingly, enhanced expression of sodium-iodide symporter and other thyroid differentiation markers, thus promoted 131I uptake. Nanoparticle-mediated application of anti-miR-31 antagomirs markedly elevated radio-sensitivity of BRAFV600E-induced PTC tumours to 131I therapy, and efficiently suppressed tumour progression in the pre-clinical mouse model.

CONCLUSIONS

Our findings elucidate a novel BRAF/MAPK-miR-31-Wnt/β-catenin regulatory mechanism underlying clinically BRAFV600E-associated DTC tumourigenesis and dedifferentiation, also highlight a potential adjuvant therapeutic strategy for advanced DTC.

Epigenetic modifications in obesity-associated diseases

The global prevalence of obesity has reached epidemic levels, significantly elevating the susceptibility to various cardiometabolic conditions and certain types of cancer. In addition to causing metabolic abnormalities such as insulin resistance (IR), elevated blood glucose and lipids, and ectopic fat deposition, obesity can also damage pancreatic islet cells, endothelial cells, and cardiomyocytes through chronic inflammation, and even promote the development of a microenvironment conducive to cancer initiation. Improper dietary habits and lack of physical exercise are important behavioral factors that increase the risk of obesity, which can affect gene expression through epigenetic modifications. Epigenetic alterations can occur in early stage of obesity, some of which are reversible, while others persist over time and lead to obesity-related complications. Therefore, the dynamic adjustability of epigenetic modifications can be leveraged to reverse the development of obesity-associated diseases through behavioral interventions, drugs, and bariatric surgery. This review provides a comprehensive summary of the impact of epigenetic regulation on the initiation and development of obesity-associated cancers, type 2 diabetes, and cardiovascular diseases, establishing a theoretical basis for prevention, diagnosis, and treatment of these conditions.

Vesicular Release and Uptake of Circular LSD1-RNAs from Non-Cancer and Cancer Lung Cells

Lysine-specific demethylase 1 (LSD1) is highly expressed in many cancer types and strongly associated with cancer progression and metastasis. Circular RNAs (circRNAs) are produced by back-splicing and influence the interactive RNA network by microRNA and protein sponging. In the present study, we aimedto identify circRNAs that derive from the LSD1-encoding KDM1A gene, and to investigate their potential to be released and uptaken by lung cancer versus non-cancer epithelial cells. We identified four circLSD1-RNAs by RT-PCR with divergent primers, followed by sequencing. The expression level of circLSD1-RNAs was then studied by quantitative PCR on cellular and extracellular fractions of lung cancer (PC9) and non-cancer primary small airway epithelial (PSAE) cells. Moreover, we established the transgenic overexpression of circLSD1-RNAs. We show that circLSD1-RNAs are primarily located in the cytoplasm, but are packaged and released from lung cancer and non-cancer cells by extracellular vesicles (EVs) and ribonucleoprotein (RNP) complexes, respectively. Proteomics demonstrated a different protein pattern of EV fractions released from PC9 versus PSAE cells. Importantly, released circLSD1-RNAs were differently taken up by PSAE and PC9 cells. In conclusion, our findings provide primary evidence that circLSD1-RNAs participate in the intercellular communication of lung cancer cells with the tumor environment.

miR-3133 is an unfavorable prognosis factor and tumor suppressor in colon cancer

Dysregulated miRNAs have been demonstrated to be associated with the progression of colon cancer. The dysregulation of miR-3133 was observed in colon cancer, but its specific function was unclear. The functional role of miR-3133 in colon cancer was investigated in this study. A total of 113 colon cancer patients were included. miR-3133 expression was evaluated by PCR. The biological effects of miR-3133 in colon cancer cells were assessed with the help of the transwell and CCK8 assay. The prognostic value of miR-3133 was estimated by a series of statistical analyses. In mechanism, the interaction between miR-3133 and RUFY3 was evaluated by luciferase reporter. The significant downregulation of miR-3133 was observed in colon cancer, which showed a significant association with the advanced TNM stage and bad survival of patients. miR-3133 and TNM stage were identified as independent prognostic indicators of colon cancer. In vitro, the overexpression of miR-3133 exerted a dramatically inhibitory effect on cellular processes of colon cancer, which were enhanced by miR-3133 knockdown. Additionally, miR-3133 could negatively regulate the luciferase activity and expression of RUFY3, which was speculated as the underlying mechanism mediating the regulatory effect of miR-3133. miR-3133 functioned as a prognostic biomarker indicating the progression and prognosis of colon cancer, and it also served as a tumor suppressor via negatively regulating RUFY3, which provides a potential therapeutic target for colon cancer.

Long non-coding RNA LBX2-AS1 predicts poor survival of colon cancer patients and promotes its progression via regulating miR-627-5p/RAC1/PI3K/AKT pathway

Colon cancer is one of the most prevalent malignant tumors across the world. Increasing studies have demonstrated that long non-coding RNAs (lncRNAs) take part in colon cancer development. Our study intends to explore the expression characteristics of LBX2-AS1, a novel lncRNA, in colon cancer and its underlying mechanisms. The results illustrated that LBX2-AS1 level was substantially increased in colon cancer tissues and was obviously correlated with the tumor volume and early distant metastasis of patients. Besides, overexpression of LBX2-AS1 remarkably boosted growth, proliferation, and metastasis and restrained apoptosis in colon cancer cells, whereas LBX2-AS1 knockdown produced the opposite effect. On the other hand, miR-627-5p, down-regulated in colon cancer tissues, was negatively associated with LBX2-AS1 expression. Functional experiments showed that miR-627-5p suppressed colon cancer growth. Mechanistically, LBX2-AS1, as an endogenous competitive RNA, targeted miR-627-5p and restrained its expression, while miR-627-5p targeted and negatively regulated the RAC1/PI3K/AKT axis. Collectively, this study has revealed that LBX2-AS1 is a poor prognostic factor of colon cancer and can regulate colon cancer progression by regulating the miR-627-5p/RAC1/PI3K/AKT pathway.

Perspective of Human Condensins Involved in Colorectal Cancer

Although many important roles are played by human condesins in condensation and segregation of mitotic chromosomes, what roles of human condensins play in colorectal cancer are still unclear at present. Recently, abnormal expressions of all eight subunits of human condensins have been found in colorectal cancer and they are expected to become potential biomarkers and therapeutic targets for colorectal cancer in the future. However, there are still no reviews on the significance of abnormal expression of human condensin subunits and colorectal cancer until now. Based on a brief introduction to the discovery and composition of human condensins, the review summarized all abnormally expressed human subunits found in colorectal cancer based on publicly published papers. Moreover, Perspective of application on abnormally expressed human subunits in colorectal cancer is further reviewed.

microRNAs: Small molecules with a large impact on colorectal cancer

Colorectal cancer (CRC) accounts for one of the main cancer-related mortality and morbidity worldwide. The molecular mechanisms of CRC development have been broadly investigated and, over the last decade, it has become evident that aberrant transcription of microRNAs (miRNAs), a class of small, noncoding RNA molecules, has a significant role in the inception and promotion of CRC. In the involved tissues of CRC, the transcription profile of miRNAs is modulated, and their expression templates are related with prognosis, diagnosis, and treatment outcomes. Here, in the current review, we attempted to discuss the latest information regarding the aberrantly expressed miRNAs in CRC and the advantages of utilizing miRNAs as biomarkers for early diagnosis and prognosis of CRC as well as potential therapeutic application. The effect of miRNAs involved in various signaling pathways, primarily p53, EGFR, Wnt, and TGF-β pathways, was clarified.

The predictive value of RNA binding proteins in colon adenocarcinoma

Background

RNA binding proteins (RBPs) play an important role in regulating post-transcriptional gene expression and have been reported to be closely associated with the occurrence and development of tumors. However, the effect of RBPs in colon cancer remains unclear.

Methods

We downloaded clinical information and transcriptome data of colon adenocarcinoma (COAD) from The Cancer Genome Atlas database (TCGA) database. After combining this data, we identified differentially expressed RBPs in normal and cancer tissues and subsequently performed Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. Prognosis-related RBPs were identified via Cox regression analysis. The samples were randomly divided into two groups; an experimental group and a control group. A predictive model was constructed by dividing the experimental group into high- and low-risk subgroups based on the scores of the prognostic-related RBPs, and the prognosis of samples in these two subgroups was compared. Then, this model was applied to the control group. Finally, the model results were verified based on an online survival database and the Human Protein Atlas (HPA) database.

Results

A total of 469 differentially expressed RBPs were identified in normal and cancer tissues. Ten prognosis-related RBPs were determined by Cox regression analysis. In the prognostic prediction model, the prognosis of high-risk patients in the experimental group was worse than that in the low-risk group, and the same result was obtained in the control group. In addition, the risk score in the Cox regression analysis showed that the model could be used as an independent prognostic factor (P<0.001). The results of the online survival analysis tool, HPA database, and the model were consistent.

Conclusions

Some specific RBPs are significantly associated with the prognosis of patients with COAD, and this finding may provide important information for the future diagnosis and treatment of patients with COAD.

A gut butyrate-producing bacterium Butyricicoccus pullicaecorum regulates short-chain fatty acid transporter and receptor to reduce the progression of 1,2-dimethylhydrazine-associated colorectal cancer

Gut microbes influence tumor development and progression in the intestines and may provide a novel paradigm for the treatment of colorectal cancer (CRC). Gut dysbiosis may be associated with the development and progression of CRC. Identifying the interactions between the colonic tract and gut microbiota may provide novel information relevant to CRC prevention. The present study examined the effects of butyrate-producing Butyricicoccus pullicaecorum (B. pullicaecorum) on mice with 1,2-dimethylhydrazine (DMH)-induced CRC and the microbial metabolite of B. pullicaecorum on CRC cells. Immunohistochemical staining of the mouse colon tissues and reverse transcription PCR of CRC cells were used to determine the protein and mRNA expression levels of the short-chain fatty acid (SCFA) transporter solute carrier family 5 member 8 (SLC5A8) and G-protein-coupled receptor 43 (GPR43). In CRC-bearing mice fed B. pullicaecorum, DMH-induced CRC regressed, body weight increased and serum carcinoembryonic antigen levels decreased. Notably, SLC5A8 and GPR43 were diffusely and moderately to strongly expressed in the neoplastic epithelial cells and underlying muscularis propria in the colons of the mice. In conclusion, administration of B. pullicaecorum or its metabolites improved the clinical outcome of CRC by activating the SCFA transporter and/or receptor. These results indicated that B. pullicaecorum was a probiotic with anti-CRC potential.

Clinical significance of serum IGFBP-3 in colorectal cancer

BACKGROUND

IGF-binding protein 3（IGFBP-3）has previously been identified as tumor marker. The present study aimed to investigate the clinical significance of serum IGFBP-3 in colorectal cancer (CRC).

METHODS

Serum was collected from 70 CRC patients and 50 healthy volunteer controls. Serum IGFBP-3 and carcinoembryonic antigen (CEA) levels were measured using electrogenerated chemiluminescence immunoassay and compared between groups. Relationships between serum IGFBP-3 level and the clinical characteristics of CRC were also analyzed. A receiver operator characteristic (ROC) curve was plotted to investigate diagnostic efficacy of serum IGFBP-3 and CEA, respectively, for CRC. Data were analyzed using SPSS 13.0.

RESULTS

Serum IGFBP-3 levels in CRC were lower than those of controls (4.68 [3.56, 5.77] vs 5.44 [4.77, 6.10] µg/mL, P < 0.05). Furthermore, serum IGFBP-3 levels were higher in early cancer stages (I and II) than those of advanced stages (III and IV) (4.78 [3.92, 5.49] vs 3.77 [2.65, 4.59] µg/mL, P < 0.05). In addition, patients with lymph node metastasis absent had elevated serum IGFBP-3 levels than those of patients with lymph node metastasis present (4.73 [3.92, 5.72] vs 4.11 [2.45, 4.83] µg/mL, P = 0.02). Finally, ROC curve indicated that serum IGFBP-3 had a better diagnostic power for CRC than CEA. When serum IGFBP-3 and carcinoembryonic antigen were used together to detect CRC, the AUC was 0.949, with a sensitivity of 75% and a specificity of 90%.

CONCLUSIONS

Serum IGFBP-3 might be a potential biomarker for CRC.

MiR-4319 suppresses colorectal cancer progression by targeting ABTB1

Background

Colorectal cancer is one of the highly malignant cancers with a poor prognosis. The exact mechanism of colorectal cancer progression is not completely known. Recently, microRNAs (miRNAs, miRs) were suggested to participate in the regulation of multiple cancer development, including colorectal cancer.

Methods

MiR-4319 expression in colorectal cancer patient samples was detected by real-time polymerase chain reaction. MiR-4319 was knocked down in the colorectal cancer cells by siRNA transfection to study the role of miR-4319 in the cell cycle and proliferation of colorectal cancer cells.

Results

MiR-4319 expression was found to be inverse correlated with survival in colorectal cancer patients. Overexpression of miR-4319 markedly reduced the proliferation of colorectal cancer cells and altered cell cycle distribution. A further experiment showed that ABTB1 is the target gene of miR-4319. MiR-4319 was regulated by PLZF.

Conclusion

Our studies indicated that reduced expression of miR-4319 was correlated with poor prognosis in colorectal cancer patients; miR-4319 also suppressed colorectal cancer cell proliferation by targeting ABTB1. ABTB1 might become an excellent therapeutic target for colorectal cancer treatment.

Downregulated microRNAs in the colorectal cancer: diagnostic and therapeutic perspectives

Colorectal cancer (CRC), the third most common cancer in the world, has no specific biomarkers that facilitate its diagnosis and subsequent treatment. The miRNAs, small single-stranded RNAs that repress the mRNA translation and trigger the mRNA degradation, show aberrant levels in the CRC, by which these molecules have been related with the initiation, progression, and drug-resistance of this cancer type. Numerous studies show the microRNAs influence the cellular mechanisms related to the cell cycle, differentiation, apoptosis, and migration of the cancer cells through the post-transcriptionally regulated gene expression. Specific patterns of the upregulated and down-regulated miRNA have been associated with the CRC diagnosis, prognosis, and therapeutic response. Concretely, the downregulated miRNAs represent attractive candidates, not only for the CRC diagnosis, but for the targeted therapies via the tumor-suppressing microRNA replacement. This review shows a general overview of the potential uses of the miRNAs in the CRC diagnosis, prognosis, and treatment with a special focus on the downregulated ones. [BMB Reports 2018; 51(11): 563-571].

Impact of the gut microbiome on the genome and epigenome of colon epithelial cells: contributions to colorectal cancer development

In recent years, the number of studies investigating the impact of the gut microbiome in colorectal cancer (CRC) has risen sharply. As a result, we now know that various microbes (and microbial communities) are found more frequently in the stool and mucosa of individuals with CRC than healthy controls, including in the primary tumors themselves, and even in distant metastases. We also know that these microbes induce tumors in various mouse models, but we know little about how they impact colon epithelial cells (CECs) directly, or about how these interactions might lead to modifications at the genetic and epigenetic levels that trigger and propagate tumor growth. Rates of CRC are increasing in younger individuals, and CRC remains the second most frequent cause of cancer-related deaths globally. Hence, a more in-depth understanding of the role that gut microbes play in CRC is needed. Here, we review recent advances in understanding the impact of gut microbes on the genome and epigenome of CECs, as it relates to CRC. Overall, numerous studies in the past few years have definitively shown that gut microbes exert distinct impacts on DNA damage, DNA methylation, chromatin structure and non-coding RNA expression in CECs. Some of the genes and pathways that are altered by gut microbes relate to CRC development, particularly those involved in cell proliferation and WNT signaling. We need to implement more standardized analysis strategies, collate data from multiple studies, and utilize CRC mouse models to better assess these effects, understand their functional relevance, and leverage this information to improve patient care.

MiR-92a Inhibits the Progress of Osteosarcoma Cells and Increases the Cisplatin Sensitivity by Targeting Notch1

Background

MicroRNAs (miRs) have been implicated in the development and progression of osteosarcoma. Here, we aimed to illustrate the important role of miR-92a on the regulation of OS development which may help to establish a novel strategy for OS diagnosis and treatment.

Materials and Methods

Cell viability was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cell cycle and apoptosis were assessed by flow cytometry with PI and PI/Annexin-V stain, respectively. The expression of proteins was examined by western blot. qPCR was used to detect the expression of RNA. Cell migration was assayed with transwell assay.

Results

MiR-92a inhibited the proliferation and the migration of OS in vitro and reduced the volume of the tumour in vivo. Further, miR-92a enhanced cisplatin sensitivity of OS. MiR-92a directly targeted Notch1.

Conclusion

Together, our results indicate that miR-92a inhibited cell growth, migration, and enhanced cisplatin sensitivity of OS cell by targeting Notch1.

Profiles of differentially expressed genes and overexpression of NEBL indicates a positive prognosis in patients with colorectal cancer

The present study aimed to identify differentially expressed genes (DEGs) in colorectal cancer (CRC) and provide novel prognostic biomarkers for CRC. The microarray dataset GSE41258 was used to screen DEGs of CRC. Subsequently, a protein-protein interaction network of DEGs and Gene Ontology analysis were performed to identify hub genes and associated biological processes. Nebulette (NEBL) and complement C1q like 1 (C1QL1) were validated using reverse transcription-quantitative polymerase chain reaction in patients with CRC. Survival analysis was performed for the two hub genes. GSE41258 dataset included 182 CRC samples and 54 normal tissues. A total of 759 DEGs, including 279 upregulated and 480 downregulated were screened between both groups. NEBL and C1QL1 were identified as the two hub genes and upregulated genes involved in various biological processes, including ‘regulation of biological quality’ and ‘response to stimulus’, respectively. Additionally, the overexpression of NEBL and C1QL1 in experimental validation was consistent with the aforementioned bioinformatics analysis results. Survival analysis suggested that overexpressed NEBL in patients with CRC was associated with a positive prognosis for overall survival. In conclusion, CRC was associated with a large group of DEGs. From the upregulated genes, overexpressed NEBL in patients CRC indicated a positive prognosis for overall survival and may be used as a prognostic biomarker for patients with CRC.

Low-level miR-646 in colorectal cancer inhibits cell proliferation and migration by targeting NOB1 expression

Aberrant expression of microRNA (miRNA) is important in the progression of various human cancers, however further investigation is required in order to fully elucidate mechanisms of and validate actions of endogenous non-coding RNAs. The present study demonstrated that the expression of miR-646 was downregulated in colorectal cancer tissues and cell lines. Notably, it was observed that miR-646, a tumor suppressor, inhibited colorectal cancer cell progression through directly targeting Nin one binding protein (NOB1) expression, which possesses anti-tumor properties in colorectal cancer. Furthermore, knockdown of NOB1 expression was responsible for the tumor-suppressive effect of miR-646. The findings suggest that miR-646 may act as a therapeutic target for the treatment of colorectal cancer.

Exosomal miRNAs and miRNA dysregulation in cancer-associated fibroblasts

Purpose

The present review aimed to assess the role of exosomal miRNAs in cancer-associated fibroblasts (CAFs), normal fibroblasts (NFs), and cancer cells. The roles of exosomal miRNAs and miRNA dysregulation in CAF formation and activation were summarized.

Methods

All relevant publications were retrieved from the PubMed database, with key words such as CAFs, CAF, stromal fibroblasts, cancer-associated fibroblasts, miRNA, exosomal, exosome, and similar terms.

Results

Recent studies have revealed that CAFs, NFs, and cancer cells can secrete exosomal miRNAs to affect each other. Dysregulation of miRNAs and exosomal miRNAs influence the formation and activation of CAFs. Furthermore, miRNA dysregulation in CAFs is considered to be associated with a secretory phenotype change, tumor invasion, tumor migration and metastasis, drug resistance, and poor prognosis.

Conclusions

Finding of exosomal miRNA secretion provides novel insights into communication among CAFs, NFs, and cancer cells. MicroRNA dysregulation is also involved in the whole processes of CAF formation and function. Dysregulation of miRNAs in CAFs can affect the secretory phenotype of the latter cells.

Colorectal Cancer: From the Genetic Model to Posttranscriptional Regulation by Noncoding RNAs

Colorectal cancer is the third most common form of cancer in developed countries and, despite the improvements achieved in its treatment options, remains as one of the main causes of cancer-related death. In this review, we first focus on colorectal carcinogenesis and on the genetic and epigenetic alterations involved. In addition, noncoding RNAs have been shown to be important regulators of gene expression. We present a general overview of what is known about these molecules and their role and dysregulation in cancer, with a special focus on the biogenesis, characteristics, and function of microRNAs. These molecules are important regulators of carcinogenesis, progression, invasion, angiogenesis, and metastases in cancer, including colorectal cancer. For this reason, miRNAs can be used as potential biomarkers for diagnosis, prognosis, and efficacy of chemotherapeutic treatments, or even as therapeutic agents, or as targets by themselves. Thus, this review highlights the importance of miRNAs in the development, progression, diagnosis, and therapy of colorectal cancer and summarizes current therapeutic approaches for the treatment of colorectal cancer.

miR-19a promotes colitis-associated colorectal cancer by regulating tumor necrosis factor alpha-induced protein 3-NF-κB feedback loops

Chronic inflammation is believed to have a crucial role in colon cancer development. MicroRNA (miRNA) deregulation is common in human colorectal cancers, but little is known regarding whether miRNA drives tumor progression by regulating inflammation. Here, we showed that miR-19a can promote colitis and colitis-associated colon cancer (CAC) development using a CAC mouse model and an acute colitis mouse model. Tumor necrosis factor-α (TNF-α) stimulation can increase miR-19a expression, and upregulated miR-19a can in turn activate nuclear factor (NF)-κB signaling and TNF-α production by targeting TNF alpha-induced protein 3 (TNFAIP3). miR-19a inhibition can also alleviate CAC in vivo. Moreover, the regulatory effects of miR-19a on TNFAIP3 and NF-κB signaling were confirmed using tumor samples from patients with colon cancer. These new findings demonstrate that miR-19a has a direct role in upregulating NF-κB signaling and that miR-19a has roles in inflammation and CAC.

miR-20b reduces 5-FU resistance by suppressing the ADAM9/EGFR signaling pathway in colon cancer

Chemoresistance is a major obstacle to cancer therapy including that of colon cancer (CC). Although the dysregulation of many miRNAs has been implicated in 5-fluorouracil (5-FU) resistance in CC cells, the specific role of miR-20b in chemoresistance has not been documented. In the present study, we first determined the expression of miR-20b by RT-PCR and the levels of a disintegrin and metalloprotease 9 (ADAM9) and epidermal growth factor receptor (EGFR) by western blotting in CC and adjacent non-cancerous tissues from 5-FU-sensitive or -resistant CC patients. Subsequently, 5-FU-sensitive (HCT116) and -resistant (HCT116-R) cells were obtained, and the levels of miR-20b, ADAM9 and EGFR were detected. Meanwhile, the 5-FU resistance of the cells was examined by assessing cell viability (by MTT assay) and apoptosis (by flow cytometry). After transfection of miR-20b into HCT116-R cells, drug resistance was reexamined. We then confirmed the relationship between miR-20b and ADAM9 by luciferase reporter assay. Finally, 5-FU resistance in HCT116 and HCT116-R cells was compared after transfection with miR-20b. Our results showed that miR-20b was expressed at lower levels in the 5-FU-resistant tissues and cells than in the 5-FU-sensitive tissues and cells. The opposite was the case for expression of ADAM9 and EGFR. In addition, we demonstrated that ADAM9 is a direct target of miR-20b and that miR-20b decreased the 5-FU resistance of HCT116-R cells. Our findings suggest that miR-20b reduces 5-FU resistance to induce apoptosis in vitro by suppressing ADAM9/EGFR in CC cells.

miR-574-3p acts as a tumor promoter in osteosarcoma by targeting SMAD4 signaling pathway

Human osteosarcoma is the most common primary bone malignancy sarcoma that affects primarily children and people <20 years old. In the present study, it was demonstrated that miR-574-3p was downregulated in human osteosarcoma U2OS, SAOS and MG63 cells lines as well as in osteosarcoma tissue compared with the normal tissues. Downregulation of miR-574-3p by antisense miR-574-3p, inhibited cell growth and induced cell apoptosis. Overexpression of miR-574-3p by transfection with miR-574-3p mimics promoted the growth of U2OS cells. The present study then identified mothers against decapentaplegic homolog 4 (SMAD4) as a target of miR-574-3p and SMAD4 was suppressed in miR-574-3p transfected cells. Overexpression of SMAD4 could rescue the promoting effects of miR-574-3p on cancer cell growth. In conclusion, miR-574-3p exerts tumor-promoting roles by targeting the tumor-suppressing gene SMAD4 and its downstream signaling in human osteosarcoma, which provides a novel target for the treatment.

miR-517a is an independent prognostic marker and contributes to cell migration and invasion in human colorectal cancer

Colorectal cancer (CRC) is a highly invasive tumor that is frequently associated with distant metastasis, which is the primary cause of poor prognosis. However, the mechanisms of metastasis remain poorly understood. MicroRNAs (miRNAs/miRs) have been considered to be implicated in CRC progression. In particular, miR-517a is proposed as a novel tumor-associated miRNA and has a potential role in tumor metastasis. The expression of miR-517a in CRC specimens was detected by reverse transcription-quantitative polymerase chain reaction. Transwell assays were performed to determine the migration and invasion of CRC cells. The putative target genes of miR-517a were disclosed using publicly available databases and western blot analysis. The present study identified that the expression of miR-517a was significantly higher in CRC tissues as compared with adjacent non-tumor tissues. Clinical analysis indicated that increased expression of miR-517a was correlated with poor prognostic features and poor long-term survival of CRC patients. In vitro evidences demonstrated that downregulation of miR-517a inhibited cell migration and invasion in HCT-116 cells. By contrast, upregulation of miR-517a increased the number of migrated and invaded SW480 cells. Notably, miR-517a expression was inversely regulated by forkhead box J3 (FOXJ3) abundance in CRC cells. Furthermore, an inverse correlation between miR-517a and FOXJ3 expression was observed in CRC tissues. In conclusion, miR-517a appears to be an independent prognostic marker for predicting survival of CRC patients, and may promote cell migration and invasion by inhibiting FOXJ3.

MiR-367 negatively regulates apoptosis induced by adriamycin in osteosarcoma cells by targeting KLF4

Diverse functions of microRNAs have been investigated in tumorigenesis in osteosarcoma (OS), involving the regulation of proliferation, invasion, migration, apoptosis and drug resistance. MiR-367 was found to be an oncogene and increased in OS. However, the function of miR-367 in drug resistance in OS cells is still unknown. In this study, we found that miR-367 was up-regulated in OS tissues and OS cell cultures. Meanwhile, treatment with adriamycin (ADR) induced apoptosis of OS cells with upregulation of miR-367. Notably, KLF4 was demonstrated to be a direct target of miR-367 by gene reporter assay, and miR-367 significantly blocked both mRNA and protein level of KLF4. In addition, overexpression of miR-367 markedly suppressed the increase of KLF4 induced by ADR in OS cells, as well as Bax and cleaved caspase-3, which were significantly reversed by anti-miR-367 transfection. Taken together, our data demonstrates that miR-367 and KLF4 play important roles in OS treatment and ADR resistance, suggesting that miR-367 is a potential biomarker of chemotherapy resistance in OS and also probably a novel therapeutic target against OS.

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miR-367 functions as an oncogene in OS targeting the tumor suppressor KLF4.

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ADR induces apoptosis in OS via miR-367/KLF4/Bax signaling pathway.

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miR-367 enhances the resistance of ADR to OS cells through suppressing KLF4.

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miR-367 could be a potential biomarker of chemotherapy resistance against OS.

Genetics and Genetic Biomarkers in Sporadic Colorectal Cancer

Sporadic colorectal cancer (CRC) is a somatic genetic disease in which pathogenesis is influenced by the local colonic environment and the patient's genetic background. Consolidating the knowledge of genetic and epigenetic events that occur with initiation, progression, and metastasis of sporadic CRC has identified some biomarkers that might be utilized to predict behavior and prognosis beyond staging, and inform treatment approaches. Modern next-generation sequencing of sporadic CRCs has confirmed prior identified genetic alterations and has classified new alterations. Each patient's CRC is genetically unique, propelled by 2-8 driver gene alterations that have accumulated within the CRC since initiation. Commonly observed alterations across sporadic CRCs have allowed classification into a (1) hypermutated group that includes defective DNA mismatch repair with microsatellite instability and POLE mutations in ∼15%, containing multiple frameshifted genes and BRAF(V600E); (2) nonhypermutated group with multiple somatic copy number alterations and aneuploidy in ∼85%, containing oncogenic activation of KRAS and PIK3CA and mutation and loss of heterozygosity of tumor suppressor genes, such as APC and TP53; (3) CpG island methylator phenotype CRCs in ∼20% that overlap greatly with microsatellite instability CRCs and some nonhypermutated CRCs; and (4) elevated microsatellite alterations at selected tetranucleotide repeats in ∼60% that associates with metastatic behavior in both hypermutated and nonhypermutated groups. Components from these classifications are now used as diagnostic, prognostic, and treatment biomarkers. Additional common biomarkers may come from genome-wide association studies and microRNAs among other sources, as well as from the unique alteration profile of an individual CRC to apply a precision medicine approach to care.

Down-regulation of MicroRNA-381 promotes cell proliferation and invasion in colon cancer through up-regulation of LRH-1

The expression and roles of MicroRNA-381 (miR-381) has been explored in several types of human cancers. However, its biological functions in colon cancer remain largely unknown. Quantitative real-time PCR assays were used to detect the expression of miR-381 in human colon cancer tissues and adjacent normal tissues. miR-381 antisense oligos and mimics were introduced into SW480 and HCT116 cells. Bioinformatic prediction analysis was performed to identify the potential targets of miR-381. Protein expression analysis, luciferase assays and rescue assays were used to confirm the substrate of miR-381. We found that miR-381 was significantly down-regulated in human colon cancer tissues, compared with adjacent normal tissues. Introduction of miR-381 antisense oligos into SW480 and HCT116 cells promoted cell proliferation and invasion. Besides, inhibition of miR-381 could also support tumor growth in the nude mice. Additionally, bioinformatic prediction suggested that the nuclear receptor liver receptor homologue 1 (LRH-1) is a target gene of miR-381. Thus, our data suggested that down-regulation of miR-381 plays an important role in the colon cancer progression.

Integrated analysis of differentially expressed mRNAs and miRNAs between hepatocellular carcinoma and their matched adjacent normal liver tissues

Hepatocellular carcinoma has a high mortality rate, thus, there is a need for improvement of prognosis of such patients. The aim of the present study was to identify differentially expressed mRNAs and miRNAs between hepatocellular carcinoma tissues and their matched adjacent normal liver tissues, and to carry out a bioinformatics analysis. Agilent 8x60K microarray technology was used to detect the changes of mRNA and miRNA expression between hepatocellular carcinoma tissues and their matched adjacent normal liver tissues. To select differentially expressed mRNAs and miRNAs, gene ontology (GO) and pathway analysis were performed using bioinformatics methods. qPCR was used to verify the microarray data. As a result, 924 mRNAs and 21 miRNAs exhibited a higher expression in the hepatocellular carcinoma tissue than their matched adjacent normal liver tissue. In comparison with the adjacent normal tissue, the carcinoma tissue showed a downregulated expression of 1,770 mRNAs and 12 miRNAs. The GO and pathway analysis showed that these RNAs were involved in the transcription process, REDOX, signal transduction, ion transport, immune response, cell adhesion and binding functions. A total of 572 target genes of 14 miRNAs were identified, most of which were involved in tumors. The results of qPCR were in concordance with the microarray results. In summary, the differentially expressed mRNAs and miRNAs that include signal transduction, immune response and many other key links may provide novel targets for early diagnosis and therapy of hepatocellular carcinoma.

Differential expressions of cancer-associated genes and their regulatory miRNAs in colorectal carcinoma

Colorectal cancer is one of the frequently seen malignancies in the world. To date, several oncogenes and tumor suppressor genes have been identified and linked to colorectal cancer pathogenesis. Although recent advances in the diagnosis and therapy of colorectal cancer are promising, identifying novel genetic contributors is still high priority. In the present study, expression profile of some cancer-related genes and their regulatory miRNA molecules were evaluated by using a high-throughput real-time PCR method. For the study, a total of 54 patients diagnosed with CRC and normal colon tissue samples of 42 healthy controls were included. For the expression analysis, total RNA was extracted from FFPE tissue samples and converted to cDNA. All expression analyses were assessed by using Fluidigm Microfluidic Dynamic Array chips for 96 samples and the reactions were held in Fluidigm BioMark™ HD System Real-Time PCR. As a result of the study, expression of the ADAMTS1, FHIT, RUNX1, RUNX3 and WWOX genes was shown to be significantly altered in CRC tissues in contrast to normal tissue samples. Moreover, miR-378a-3p, miR-155-5p, miR-193b-3p, miR-96-5p, miR-17-5p, miR-27a-3p, miR-133b, miR-203a, miR-205-5p, miR-34c-5p, miR-130a-3p, miR-301a-3p, miR-132-3p, miR-222-3p, miR-34a-5p, miR-21-5p, miR-29a-3p and miR-29b-3p were found to be significantly deregulated in CRC. Consequently, results of the current study strongly suggest the involvement of novel cancer-related genes and their regulatory miRNAs in CRC physiopathology.