MicroRNA 26b promotes colorectal cancer metastasis by downregulating phosphatase and tensin homolog and wingless-type MMTV integration site family member 5A

The role of miRNAs in the pathogenesis, diagnosis, and treatment of colorectal cancer and colitis-associated cancer

MicroRNAs (miRNAs) are a group of noncoding single-stranded RNA biomolecules that act in posttranscriptional regulation of gene expression. Their role in the development of inflammatory bowel disease (IBD), colitis-associated cancer (CAC), and colorectal cancer (CRC) is currently under investigation. A few miRNAs present promising results in terms of diagnostic or therapeutic use, for example, miR-21 increases in CRC and inflammation, while also being a possible target for cancer therapy; miR-301a increases in inflammation but only in patients with IBD; miR-31 increases in CRC, especially in advanced stages, namely III-IV in TNM scale; miR-200 family plays a role in carcinogenesis of CRC and other tumors; examined as a group, miR-31-5p, miR-223-3p, and let-7f-5p trigger and exacerbate CAC; miR-19a could potentially be used in therapy and prevention of both CRC and CAC. Here, we discuss available studies and outline future directions concerning the validity of using miRNAs in the diagnosis and/or therapy of IBD, CAC, and CRC. Extensive research confirms that miRNAs play an important role in the pathogenesis of CAC and CRC. Since the significantly altered expression of certain miRNAs is an early prognostic marker for the development of these diseases, miRNAs have the potential to serve as diagnostic tools, enabling quick and straightforward disease detection.

Molecular detection of exosomal miRNAs of blood serum for prognosis of colorectal cancer

Colorectal cancer (CRC) is the third most common cancer affecting people. The discovery of new, non-invasive, specific, and sensitive molecular biomarkers for CRC may assist in the diagnosis and support therapeutic decision making. Exosomal miRNAs have been demonstrated in carcinogenesis and CRC development, which makes these miRNAs strong biomarkers for CRC. Deep sequencing allows a robust high-throughput informatics investigation of the types and abundance of exosomal miRNAs. Thus, exosomal miRNAs can be efficiently examined as diagnostic biomarkers for disease screening. In the present study, a number of 660 mature miRNAs were detected in patients diagnosed with CRC at different stages. Of which, 29 miRNAs were differentially expressed in CRC patients compared with healthy controls. Twenty-nine miRNAs with high abundance levels were further selected for subsequent analysis. These miRNAs were either highly up-regulated (e.g., let-7a-5p, let-7c-5p, let-7f-5p, let-7d-3p, miR-423-5p, miR-3184-5p, and miR-584) or down-regulated (e.g., miR-30a-5p, miR-99-5p, miR-150-5p, miR-26-5p and miR-204-5p). These miRNAs influence critical genes in CRC, leading to either tumor growth or suppression. Most of the reported diagnostic exosomal miRNAs were shown to be circulating in blood serum. The latter is a novel miRNA that was found in exosomal profile of blood serum. Some of the predicted target genes of highly expressed miRNAs participate in several cancer pathways, including CRC pathway. These target genes include tumor suppressor genes, oncogenes and DNA repair genes. Main focus was given to multiple critical signaling cross-talking pathways including transforming growth factor β (TGFβ) signaling pathways that are directly linked to CRC. In conclusion, we recommend further analysis in order to experimentally confirm exact relationships between selected differentially expressed miRNAs and their predicted target genes and downstream functional consequences.

[MiR-26-3p regulates proliferation, migration, invasion and apoptosis of glioma cells by targeting CREB1]

OBJECTIVE

To investigate the regulatory role of miR-26b-3p in proliferation, migration and invasion of glioma.

METHODS

The expressions of miR-26b-3p and cAMP-responsive element binding protein 1 (CREB1) in gliomas of different pathological grades were detected with RT-qPCR and Western blotting. Bioinformatic methods were used to analyze the target sequence of miRNA-26b-3p binding to CREB1, and dual luciferase gene reporter experiment was performed to explore the mechanism for targeted regulation of CREB1 by miR-26b-3p. Glioma U251 cells were treated with miR-26b-3p mimic or inhibitor, and the changes in CREB1 expression and cell proliferation, migration, invasion and apoptosis were determined with Western blotting, CCK-8 assay, wound healing assay, Transwell assay, and flow cytometry.

RESULTS

The expression of miR-26b-3p decreased while CREB1 expression increased significantly as the pathological grade of gliomas increased (P < 0.05). Dual luciferase gene reporter experiment confirmed that CREB1 was a downstream target of miR-26b-3p. Inhibition of miR-26b-3p significantly upregulated the expression of CERB1, suppressed apoptosis and promoted proliferation and invasion of glioma cells, and overexpression of miR-26b-3p produced the opposite effects (P < 0.05).

CONCLUSION

MiR-26b-3p regulates CREB1 expression to modulate apoptosis, proliferation, migration and invasion of glioma cells, thereby participating in tumorigenesis and progression of glioma.

Using machine learning approach for screening metastatic biomarkers in colorectal cancer and predictive modeling with experimental validation

Colorectal cancer (CRC) liver metastasis accounts for the majority of fatalities associated with CRC. Early detection of metastasis is crucial for improving patient outcomes but can be delayed due to a lack of symptoms. In this research, we aimed to investigate CRC metastasis-related biomarkers by employing a machine learning (ML) approach and experimental validation. The gene expression profile of CRC patients with liver metastasis was obtained using the GSE41568 dataset, and the differentially expressed genes between primary and metastatic samples were screened. Subsequently, we carried out feature selection to identify the most relevant DEGs using LASSO and Penalized-SVM methods. DEGs commonly selected by these methods were selected for further analysis. Finally, the experimental validation was done through qRT-PCR. 11 genes were commonly selected by LASSO and P-SVM algorithms, among which seven had prognostic value in colorectal cancer. It was found that the expression of the MMP3 gene decreases in stage IV of colorectal cancer compared to other stages (P value < 0.01). Also, the expression level of the WNT11 gene was observed to increase significantly in this stage (P value < 0.001). It was also found that the expression of WNT5a, TNFSF11, and MMP3 is significantly lower, and the expression level of WNT11 is significantly higher in liver metastasis samples compared to primary tumors. In summary, this study has identified a set of potential biomarkers for CRC metastasis using ML algorithms. The findings of this research may provide new insights into identifying biomarkers for CRC metastasis and may potentially lay the groundwork for innovative therapeutic strategies for treatment of this disease.

Lynch Syndrome Biopathology and Treatment: The Potential Role of microRNAs in Clinical Practice

Lynch syndrome (LS), also known as Hereditary Non-Polyposis Colorectal Cancer (HNPCC), is an autosomal dominant cancer syndrome which causes about 2-3% of cases of colorectal carcinoma. The development of LS is due to the genetic and epigenetic inactivation of genes involved in the DNA mismatch repair (MMR) system, causing an epiphenomenon known as microsatellite instability (MSI). Despite the fact that the genetics of the vast majority of MSI-positive (MSI+) cancers can be explained, the etiology of this specific subset is still poorly understood. As a possible new mechanism, it has been recently demonstrated that the overexpression of certain microRNAs (miRNAs, miRs), such as miR-155, miR-21, miR-137, can induce MSI or modulate the expression of the genes involved in LS pathogenesis. MiRNAs are small RNA molecules that regulate gene expression at the post-transcriptional level by playing a critical role in the modulation of key oncogenic pathways. Increasing evidence of the link between MSI and miRNAs in LS prompted a deeper investigation into the miRNome involved in these diseases. In this regard, in this study, we discuss the emerging role of miRNAs as crucial players in the onset and progression of LS as well as their potential use as disease biomarkers and therapeutic targets in the current view of precision medicine.

WNT5A: a double-edged sword in colorectal cancer progression

The Wnt signaling pathway is known to play a crucial role in cancer, and WNT5A is a member of this pathway that binds to the Frizzled (FZD) and Receptor Tyrosine Kinase-Like Orphan Receptor (ROR) family members to activate non-canonical Wnt signaling pathways. The WNT5A pathway is involved in various cellular processes, such as proliferation, differentiation, migration, adhesion, and polarization. In the case of colorectal cancer (CRC), abnormal activation or inhibition of WNT5A signaling can lead to both oncogenic and antitumor effects. Moreover, WNT5A is associated with inflammation, metastasis, and altered metabolism in cancer cells. This article aims to discuss the molecular mechanisms and dual roles of WNT5A in CRC.

Overexpression of miRNA 26a and 26b with MMP-9 are valuable diagnostic biomarkers for colorectal cancer patients

Background: The key role of miRNA expression in incidence and progression of colorectal cancer (CLC) have been developed over the last decade. Materials & methods: A total of 153 subjects were enrolled into two phases: 14 selected miRNAs were first evaluated in 50 subjects, then miR-26a and miR-26b relative expression were further evaluated in 103 subjects and their target protein MMP-9 was measured. Results: miR-26a and -26b showed highly significant overexpression. Both miR-26a and -26b (p < 0.001) had high diagnostic efficacy for CRC. There was a significant increase in serum MMP-9 protein in CRC patients with positive correlation with miR-26a and -26b expression levels (p < 0.001). Conclusion: miRNA 26a and 26b with MMP-9 can be used as diagnostic biomarker for CRC patients.

Lipid Handling Protein Gene Expression in Colorectal Cancer: CD36 and Targeting miRNAs

The reprogramming of lipid metabolism has been highlighted in colorectal cancer (CRC) studies, suggesting a critical role for the scavenger receptor CD36 and fatty acid synthase (FASN) in this malignancy. In this study, we analyzed the gene expression levels of CD36, FASN, the cell surface glypican 4 (GPC4), and the two transporters SLC27A3 and SLC27A4 in 39 paired tumoral and peritumoral tissues from patients with CRC compared with 18 normal colonic mucosae. Moreover, the levels of seven miRNAs targeting CD36 and most of the analyzed genes were evaluated. We found a significant impairment of the expression of all the analyzed genes except GPC4 as well as the differential expression of miR-16-5p, miR-26b-5p, miR-107, miR-195-5p, and miR-27a-3p in the colonic mucosa of CRC patients. Interestingly, CD36 and miR-27a-3p were downregulated and upregulated, respectively, in tumoral tissues compared to peritumoral and control tissues, with a significant negative correlation in the group of patients developing lymph node metastasis. Our results sustain the relationship between CRC and fatty acid metabolism and emphasize the importance of related miRNAs in developing new therapeutic strategies.

Matrine Inhibits Proliferation, Invasion, and Migration and Induces Apoptosis of Colorectal Cancer Cells Via miR-10b/PTEN Pathway

Background: Colorectal cancer (CRC) is the third most common malignancy worldwide. Matrine can act as a potential antitumor drug, and its antitumor activities have been tested in various cancers, including CRC. However, the effect of matrine and the related mechanisms on CRC cells remains poorly defined. Materials and Methods: CRC cells were treated with different concentrations of matrine, and then MTT, flow cytometric, and transwell assays were used to assess cell proliferation, apoptosis, invasion, and migration. MiR-10b-5p and Phosphatase and tensin homolog (PTEN) expression levels were measured by quantitative real-time polymerase chain reaction and Western blot assay. The binding interaction of miR-10b-5p and PTEN were predicted by TargetScan and verified by a dual-luciferase reporter and RIP assay. The effect of matrine, miR-10b-5p, and PTEN on CRC cell proliferation, apoptosis, migration, and invasion was detected by MTT, flow cytometric, and transwell assays severally. Results: Matrine notably restrained proliferation, invasion, and migration and boosted apoptosis of CRC cells, as well as downregulated miR-10b-5p expression and upregulated PTEN protein level. PTEN was a direct target of miR-10b-5p in CRC cells. MiR-10b-5p knockdown and matrine treatment inhibited cell proliferation, migration, and invasion and induced apoptosis, and reintroduction of si-PTEN partly regained the inhibiting effect. Besides, MiR-10b-5p knockdown and matrine treatment repressed CRC growth in vivo. Conclusion: Matrine could suppress proliferation, migration, and invasion and induce apoptosis of CRC cells via the miR-10b/PTEN pathway, providing the potential molecular mechanism of matrine in blocking CRC progression.

The biochemical and clinical implications of phosphatase and tensin homolog deleted on chromosome ten in different cancers

Phosphatase and tensin homolog deleted on chromosome ten (PTEN) is widely known as a tumor suppressor gene. It is located on chromosome 10q23 with 200 kb, and has dual activity of both protein and lipid phosphatase. In addition, as a targeted gene in multiple pathways, PTEN has a variety of physiological activities, such as those regulating the cell cycle, inducing cell apoptosis, and inhibiting cell invasion, etc. The PTEN gene have been identified in many kinds of cancers due to its mutations, deletions and inactivation, such as lung cancer, liver cancer, and breast cancer, and they are closely connected with the genesis and progression of cancers. To a large extent, the tumor suppressive function of PTEN is realized through its inhibition of the PI3K/AKT signaling pathway which controls cells apoptosis and development. In addition, PTEN loss has been associated with the prognosis of many cancers, such as lung cancer, liver cancer, and breast cancer. PTEN gene is related to many cancers and their pathological development. On the basis of a large number of related studies, this study describes in detail the structure, regulation, function and classical signal pathways of PTEN, as well as the relationship between various tumors related to PTEN. In addition, some drug studies targeting PTEN/PI3K/AKT/mTOR are also introduced in order to provide some directions for experimental research and clinical treatment of tumors.

Recombinant water stress protein 1 (Re-WSP1) suppresses colon cancer cell growth through the miR-539/β-catenin signaling pathway

BACKGROUND

Nostoc commune Vauch. is a nitrogen-fixing blue-green algae that expresses a large number of active molecules with medicinal properties. Our previous study found that a water stress protein (WSP1) from N. commune and its recombinant counterpart (Re-WSP1) exhibited significant anti-colon cancer activity both in vitro and in vivo. This study is to investigate the effects of Re-WSP1 on proliferation of colon cancer cells and to elucidate the relevant mechanisms.

METHODS

Real-time quantitative PCR was used to detect the expression of miR-539 in colon cancer HT-29 and DLD1 cells. Colon cancer cells were transfected with miR-539 mimics and negative controls, and cell proliferation were detected by CCK8 and clonogenic assays. The target gene of miR-539 was predicted, and the dual luciferase reporter gene experiment was used to verify the target gene. After colon cancer cells were transfected with miR-539 mimics or inhibitors, the expression of target gene β-catenin was detected by Western blot. miR-539 inhibitor confirmed cell proliferation.

RESULTS

Re-WSP1 inhibited colon cancer cell growth in a dose-dependent manner. Re-WSP1 inhibited the expression of β-catenin, which was partly reversed by LiCl treatment. Quantitative PCR analysis showed that the expression of miR-539 was significantly upregulated after Re-WSP1 treatment. Moreover, miR-539 negatively regulated the expression of β-catenin by directly binding to the 3'UTR of β-catenin mRNA. The cell growth inhibition and the decrease in β-catenin expression induced by Re-WSP1 were significantly reversed by miR-539 inhibitor.

CONCLUSION

Re-WSP1 suppresses colon cancer cell growth via the miR-539/β-catenin axis.

Clinical Importance of Wnt5a in the Pathogenesis of Colorectal Cancer

Wnt5a is one of the potent signaling molecules that initiates responses involved in cancer through activation of both canonical and noncanonical signaling cascades. Wnt5a both directly and indirectly triggers cancer-associated signaling pathways based on the cancer type. In colorectal cancer (CRC), altering Wnt5a expression can influence several cellular processes of tumor cells, including proliferation, differentiation, migration, invasion, and metastasis. This review summarizes the molecular mechanisms and clinical importance of Wnt5a in the pathogenesis of CRC for better understanding the pathogenesis and its potential role as a prognostic marker and as an appropriate therapeutic target in the treatment of this disease in the future.

Predictive Efficacy of MiR-125b-5p, MiR-17-5p, and MiR-185-5p in Liver Metastasis and Chemotherapy Response Among Advanced Stage Colorectal Cancer Patients

MicroRNAs (miRNAs), a class of small non-coding RNAs represent potential biomarkers for colorectal cancer (CRC). The study hypothesized that miRNAs associated with liver metastases may also contribute to assessing treatment response when associated to plasma exosomes. In this study, we used two sets of biological samples, a collection of tumor tissues harvested from patients with CRC with and without liver metastases, and a collection of plasma from CRC patients with and without response to FOLFOX4/FOLFIRI regimens. We investigated 10 target miRNAs in the tissue of 28 CRC patients and identified miR-125b-5p, miR-17-5p, and miR-185-5p to be associated with liver metastasis. Further, we investigated the three miRNAs at the exosomal level in a plasma collection to test their association with chemotherapy response. Our data suggest that the elevated plasma levels of miR-17-5p and miR-185-5p could be predictive of treatment response. Overexpression of miR-17-5p and underexpression of miR-125b-5p and miR-185-5p in CRC tissue seem to be associated with metastatic potential. On the other hand, an increased expression of miR-125b-5p in plasma exosomes was potentially correlated with a more aggressive CRC phenotype.

WNT5a in Colorectal Cancer: Research Progress and Challenges

Despite the clinical development of new adjuvant and neoadjuvant chemotherapy drugs, colorectal cancer is still one of the leading causes of cancer-related death in human beings. WNT5a, an autocrine and paracrine β-catenin independent ligand, has been shown to induce tumor inhibition and carcinogenic signals, depending on the type of cancer. In patients with colorectal cancer, WNT5a triggers a variety of downstream signaling pathways, which mainly affect the migration and invasion of tumor cells. This article reviews the mechanism and therapeutic potential of WNT5a in colorectal cancer. In short, an in-depth understanding of the role of WNT5a in colorectal cancer is very helpful to better deal with this disease.

Portrait of Cancer Stem Cells on Colorectal Cancer: Molecular Biomarkers, Signaling Pathways and miRNAome

Colorectal cancer (CRC) is a leading cause of cancer death worldwide, and about 20% is metastatic at diagnosis and untreatable. Increasing evidence suggests that the heterogeneous nature of CRC is related to colorectal cancer stem cells (CCSCs), a small cells population with stemness behaviors and responsible for tumor progression, recurrence, and therapy resistance. Growing knowledge of stem cells (SCs) biology has rapidly improved uncovering the molecular mechanisms and possible crosstalk/feedback loops between signaling pathways that directly influence intestinal homeostasis and tumorigenesis. The generation of CCSCs is probably connected to genetic changes in members of signaling pathways, which control self-renewal and pluripotency in SCs and then establish function and phenotype of CCSCs. Particularly, various deregulated CCSC-related miRNAs have been reported to modulate stemness features, controlling CCSCs functions such as regulation of cell cycle genes expression, epithelial-mesenchymal transition, metastasization, and drug-resistance mechanisms. Primarily, CCSC-related miRNAs work by regulating mainly signal pathways known to be involved in CCSCs biology. This review intends to summarize the epigenetic findings linked to miRNAome in the maintenance and regulation of CCSCs, including their relationships with different signaling pathways, which should help to identify specific diagnostic, prognostic, and predictive biomarkers for CRC, but also develop innovative CCSCs-targeted therapies.

miR-26b regulates cell proliferation and apoptosis of CD117+CD44+ ovarian cancer stem cells by targeting PTEN

Ovarian cancer (OC) is the one of the most common cancer in women globally. However, it still represents the most dangerous gynecologic malignancy even with the advances in detection and therapeutics. Thus, there is an urgent need in finding more effective therapeutic options for OC patients including cancer stem cells (CSC). MicroRNAs (miRNAs) are small, endogenous, and non-coding RNAs that play critical roles in the progression of various types of tumor. Our aim of this study was to find the regulatory function of microRNA-26 (miRNA-26b) on the cell proliferation and apoptosis of ovarian CSCs. Our studies show that miR-26b is under-regulated in human CD117+CD44+ ovarian CSCs. The miR-26b overexpression inhibits the cell proliferation and promotes cell apoptosis. Moreover, phosphatase and tensin homolog (PTEN) is found to be a functional target of miR-26b. Moreover, PTEN overexpression reversed the effects of miR-26b on the cell proliferation and apoptosis. PTEN overexpression remarkably accelerated the cell proliferation, and inhibited cell apoptosis. These results indicate that miR-26b regulates cell proliferation and apoptosis of CD117+CD44+ ovarian CSCs by targeting PTEN.>.

Glutathione Synthesis in Cancer Cells

Tripeptide GSH is associated not only with the control and maintenance of redox cell homeostasis, but also with the processes of detoxification, proliferation, cell differentiation, and regulation of cell death. Disruptions in GSH synthesis and changes in the GSH/GSSG ratio are common for many pathological conditions, including malignant neoplasms. Numerous data indicate the importance of GSH and the GSH/GSSG ratio in the regulation of tumor cell viability, in the initiation of tumor development, progression, and drug resistance. However, control of the mechanism of GSH synthesis in malignant tumors remains poorly understood. This review discusses the features of GSH synthesis and its regulation in tumor cells. The role of GSH in the mechanisms of apoptosis, necroptosis, ferroptosis, and autophagy is considered.

Integrated analysis of competing endogenous RNA in esophageal carcinoma

Background

The Competing endogenous RNA (CeRNA) network plays important roles in the development and progression of multiple human cancers. Increasing attention has been paid to CeRNA in esophageal carcinoma (ESCA).

Methods

We explored The Cancer Genome Atlas (TCGA) database and then analyzed the RNAs of 142 samples to obtain long non-coding RNAs (lncRNAs), micro RNAs (miRNAs), and messenger RNAs (mRNAs) with different expression trends alongside the progress of ESCA. A series test of cluster (STC) analysis was carried out to identify a set of unique model expression tendencies. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were used to validate the function of key genes that were obtained from the STC analysis.

Results

Through our analysis, 272 lncRNAs, 87 miRNAs, and 692 mRNAs showed upward expression or downward expression trends, and these molecules were tightly involved in cell cycle, pathways in cancer, metabolic processes, and protein phosphorylation, among others. Ultimately, we constructed a CeRNA network containing a total of 71 lncRNAs, 56 miRNAs, and 125 mRNAs. The overall survival (OS) was analyzed using univariate Cox regression analysis to clarify the relationship between these key molecules from the CeRNA network and the prognosis of ESCA patients. Through survival analysis, we finally screened out two lncRNAs (DLEU2, RP11-890B15.3), three miRNAs (miR-26b-3p, miR-92a-3p, miR-324-5p), and one mRNA (SIK2) as crucial prognostic factors for ESCA.

Conclusions

The novel CeRNA network that we constructed will provide new novel prognostic biomarkers and therapeutic targets for patients with ESCA.

MicroRNAs: Multifaceted Regulators of Colorectal Cancer Metastasis and Clinical Applications

Colorectal cancer (CRC) is the third-commonest malignant cancer, and its metastasis is the major reason for cancer-related death. The process of metastasis is highly coordinated and involves a complex cascade of multiple steps. In recent years, miRNAs, as highly conserved, endogenous, noncoding, single-stranded RNA, has been confirmed to be involved in the development of various cancers. Considering that miRNA is also involved in a series of biological behaviors, regulating CRC occurrence and development, we review and summarize the role of miRNAs and related signaling pathways in several CRC-metastasis stages, including invasion and migration, mobility, metabolism, epithelial-mesenchymal transition, tumor-microenvironment communication, angiogenesis, anoikis, premetastatic-niche formation, and cancer stemness. In addition, we review the application of miRNAs as diagnostic CRC markers and in clinical treatment resistance. This review can contribute to understanding of the mechanism of miRNAs in CRC progression and provide a theoretical basis for clinical CRC treatment.

The significance of microRNA deregulation in colorectal cancer development and the clinical uses as a diagnostic and prognostic biomarker and therapeutic agent

Colorectal cancer (CRC) is one of the most widely recognized and deadly malignancies worldwide. Although death rates have declined over the previous decade, mainly because of enhanced screening or potential treatment alternatives, CRC remains the third leading cause of cancer-related mortality globally, with an estimated incidence of over 1 million new cases and approximately 600 000 deaths estimated yearly. Therefore, many scientific efforts are put into the development of new diagnostic biomarkers for CRC. MicroRNAs (miRNAs), one of the epigenetics categories, have demonstrated significant roles in carcinogenesis and progression through regulating epithelial-mesenchymal transition (EMT), oncogenic signaling pathways, and metastasis. Dysregulation of miRNAs expression has been reported in many cancers, including CRC. The expression profile of miRNAs is reproducibly altered in CRC, and their expression patterns are associated with diagnosis, prognosis, and therapeutic outcomes in CRC. Recently, many studies were conducted on the dysregulation of miRNAs as a diagnostic and prognostic biomarker in CRC. Among them, some miRNAs, which include miR-21, miR-34 family, miR-155, miR-224, and miR-378, have been more studied in CRC with more prominent roles in diagnosis, prognosis, and therapy. In the present review, we summarized the latest information regarding the dysregulated miRNAs in CRC and the advantages of using miRNAs as a biomarker for CRC diagnosis, treatment, and their function in different signaling pathways involved in CRC progression. Moreover, we described the translation of miRNA research to potential therapeutic applications in the management of CRC in clinical settings.

MicroRNAs target the Wnt/β‑catenin signaling pathway to regulate epithelial‑mesenchymal transition in cancer (Review)

Epithelial‑mesenchymal transition (EMT), during which cancer cells lose the epithelial phenotype and gain the mesenchymal phenotype, has been verified to result in tumor migration and invasion. Numerous studies have shown that dysregulation of the Wnt/β‑catenin signaling pathway gives rise to EMT, which is characterized by nuclear translocation of β‑catenin and E‑cadherin suppression. Wnt/β‑catenin signaling was confirmed to be affected by microRNAs (miRNAs), several of which are down‑ or upregulated in metastatic cancer cells, indicating their complex roles in Wnt/β‑catenin signaling. In this review, we demonstrated the targets of various miRNAs in altering Wnt/β‑catenin signaling to promote or inhibit EMT, which may elucidate the underlying mechanism of EMT regulation by miRNAs and provide evidence for potential therapeutic targets in the treatment of invasive tumors.

miRNA Regulation of Glutathione Homeostasis in Cancer Initiation, Progression and Therapy Resistance

Glutathione (GSH) is the most abundant antioxidant that contributes to regulating the cellular production of Reactive Oxygen Species (ROS) which, maintained at physiological levels, can exert a function of second messengers in living organisms. In fact, it has been demonstrated that moderate amounts of ROS can activate the signaling pathways involved in cell growth and proliferation, while high levels of ROS induce DNA damage leading to cancer development. Therefore, GSH is a crucial player in the maintenance of redox homeostasis and its metabolism has a role in tumor initiation, progression, and therapy resistance. Our recent studies demonstrated that neuroblastoma cells resistant to etoposide, a common chemotherapeutic drug, show a partial monoallelic deletion of the locus coding for miRNA 15a and 16-1 leading to a loss of these miRNAs and the activation of GSH-dependent responses. Therefore, the aim of this review is to highlight the role of specific miRNAs in the modulation of intracellular GSH levels in order to take into consideration the use of modulators of miRNA expression as a useful strategy to better sensitize tumors to current therapies.

MicroRNA-26b-3p/ANTXR1 signaling modulates proliferation, migration, and apoptosis of glioma

Glioma is a common malignant human brain tumor. The progression of glioma is associated with dysregulation of various microRNAs. Previous studies have demonstrated that microRNA-26b-3p (miR-26b-3p) is correlated with the pathogenesis of various tumors, but the functional role of miR-26b-3p and its underlying mechanisms in glioma are not clear. Here, we found that overexpression of miR-26b-3p repressed cell migration and proliferation and promoted apoptosis. In contrast, the opposite effects were observed when miR-26b-3p was inhibited in glioma cells. Anthrax toxin receptor 1 (ANTXR1) was confirmed to be a downstream molecule of miR-26b-3p. Reintroduction of ANTXR1 with an ORF region rescued the suppressive effects of miR-26b-3p on proliferation and migration, and inhibited the apoptosis of glioma cells. Moreover, the downstream target of miR-26b-3p, ANTXR1, was increased in glioma tissues and was inversely correlated with miR-26b-3p. MiR-26b-3p and ANTXR1 were correlated with the severity of glioma. Taken together, these results demonstrate that miR-26b-3p is a critical modulator of glioma via its downstream molecule, ANTXR1. Further, the miR-26b-3p/ANTXR1 axis may serve as a treatment or diagnostic target in glioma.

MiR-26b suppresses hepatocellular carcinoma development by negatively regulating ZNRD1 and Wnt/β-catenin signaling

Previous studies have indicated that Zinc ribbon domain-containing 1 (ZNRD1) is attributed to the carcinogenesis of human tumors. However, the role of ZNRD1 and its regulation in hepatocellular carcinoma (HCC) are still largely unclear. In this study, we examined the expression profiles of ZNRD1 in HCC tissues by immunohistochemistry (IHC) and publicly datasets analysis. In vitro and in vivo experiments were conducted to identify the function of ZNRD1 in HCC. In addition, miRNA potentially targeting ZNRD1 was predicted by bioinformatics analysis and further verified via in vitro experiments. Our results revealed that ZNRD1 was frequently upregulated in HCC tissues compared with that in nontumor tissues. High ZNRD1 expression in HCC tissues was positively associated with advanced tumor stage and poor prognosis. Function experiments showed that knockdown of ZNRD1 inhibited cell growth and invasion in vitro, and suppressed tumor development in vivo. Moreover, ZNRD1 promoted the activation of Wnt/β-catenin signaling pathway in HCC. Importantly, miR-26b directly inhibited the transcription activity of ZNRD1. Overexpression of ZNRD1 dramatically abolished the inhibitory effects of miR-26b on HCC cells. Taken together, our results uncover a novel mechanistic role for miR-26b/ZNRD1 axis in HCC, proposing ZNRD1 inhibition as a potent therapeutic strategy for hepatocellular carcinoma.

Role of Regulatory Oncogenic or Tumor Suppressor miRNAs of PI3K/AKT Signaling Axis in the Pathogenesis of Colorectal Cancer

Colorectal cancer (CRC) is the leading cause of cancer death worldwide and its incidence is increasing. In most patients with CRC, the PI3K/AKT signaling axis is over-activated. Regulatory oncogenic or tumor suppressor microRNAs (miRNAs) for PI3K/AKT signaling regulate cell proliferation, migration, invasion, angiogenesis, as well as resistance to chemo-/radio-therapy in colorectal cancer tumor tissues. Thus, regulatory miRNAs of PI3K/AKT/mTOR signaling represent novel biomarkers for new patient diagnosis and obtaining clinically invaluable information from post-treatment CRC patients for improving therapeutic strategies. This review summarizes the current knowledge of miRNAs' regulatory roles of PI3K/AKT signaling in CRC pathogenesis.

The Impact of miRNA in Colorectal Cancer Progression and Its Liver Metastases

Colorectal cancer (CRC) is one of the most commonly diagnosed malignancies with a high incidence and mortality rate. An essential challenge in colorectal cancer management is to identify new prognostic factors that could better estimate the evolution and treatment responses of this disease. Considering their role in cancer development, progression and metastasis, miRNAs have become an important class of molecules suitable for cancer biomarkers discovery. We performed a systematic search of studies investigating the role of miRNAs in colorectal progression and liver metastasis published until October 2018. In this review, we present up-to-date information regarding the specific microRNAs involved in CRC development, considering their roles in alteration of Wnt/βcatenin, EGFR, TGFβ and TP53 signaling pathways. We also emphasize the role of miRNAs in controlling the epithelial⁻mesenchymal transition of CRC cells, a process responsible for liver metastasis in a circulating tumor cell-dependent manner. Furthermore, we discuss the role of miRNAs transported by CRC-derived exosomes in mediating liver metastases, by preparing the secondary pre-metastatic niche and in inducing liver carcinogenesis in a Dicer-dependent manner.

ROCK inhibitor enhances the growth and migration of BRAF-mutant skin melanoma cells

Rho-associated protein kinase (ROCK) plays crucial roles in the proliferation and migration of different types of cells. ROCK inhibitor Y-27632 was previously reported to inhibit melanoma cell growth, and ROCK signaling was suggested to be a therapeutic target for treating melanoma. However, the negative effect of Y-27632 on melanoma cells was mainly seen in studies on murine B16 melanoma cells. Here, we reported that ROCK inhibitor actually promoted human melanoma cell growth and migration in vitro. Y-27632 increased the growth and migration of BRAF-mutated melanoma cells but had a negative effect on wild-type melanoma cells or primary melanocytes. We discovered that Y-27632 enhanced the growth of BRAF-mutated melanoma cells through increased ATK and ERK activity. The in vivo study further confirmed the in vitro finding. These data suggested that the effect of ROCK inhibitor on melanoma cells is cell-context dependent, and the application of ROCK inhibitor in the treatment of melanoma requires further study.

miR‑200b‑3p inhibits proliferation and induces apoptosis in colorectal cancer by targeting Wnt1

MicroRNA (miR)-200b-3p is downregulated in multiple human cancer types. Wnt signaling serves a role in human colorectal cancer (CRC). The present study aimed to examine the effect of miR-200b-3p on human CRC and its potential association with Wnt signaling. The Cell Counting Kit-8 (CCK-8) was employed to assess cell viability. A flow cytometric assay was conducted to examine cell proliferation and apoptosis. The regulation model of miR-200b-3p and Wnt1 was assessed by a luciferase reporter assay. A commercial kit was used to evaluate the activity of caspase-3 following treatment of the cells by miR-200b-3p or Wnt1. The expression of target factors was determined by a quantitative real-time polymerase chain reaction and western blot analysis. The expression of miR-200b-3p was decreased in human CRC tissues and in cell lines. The bioinformatics analysis and the luciferase reporter assay revealed that Wnt1 may be a direct target of miR-200b-3p. Moreover, the viability and proliferation of CRC cells was suppressed by miR-200b-3p. miR-200b-3p additionally induced apoptosis in CRC cells. Furthermore, the caspase-3 activity was enhanced in the miR-200b-3p mimics group. The expression of antigen Ki-67 (additionally termed KI-67) and β-catenin was decreased, while the expression of cleaved caspase-3 was increased by miR-200b-3p. In conclusion, miR-200b-3p inhibited proliferation and induced apoptosis in CRC cells by inactivating Wnt/β-catenin signaling. The present study provided potential biomarkers and candidate modalities for the management of CRC.

MicroRNA 26b promotes colorectal cancer metastasis by downregulating phosphatase and tensin homolog and wingless-type MMTV integration site family member 5A

Invasion and metastasis are crucially important factors in the survival of malignant tumors. Epithelial-mesenchymal transition (EMT) is an early step in metastatic progression and the presence of cancer stem cells is closely related to tumor survival, proliferation, metastasis, and recurrence. Herein we report that ectopic overexpression of microRNA 26b (miR-26b) in colorectal cancer (CRC) cell lines promoted EMT and stem cell-like phenotypes in vitro. Furthermore, miR-26b directly targeted and suppressed multiple tumor suppressors, including phosphatase and tensin homolog (PTEN) and wingless-type MMTV integration site family member 5A (WNT5A). Notably, miR-26b is markedly upregulated in tumor samples from patients with lymphatic metastases. These results indicate that miR-26b promotes CRC metastasis by downregulating PTEN and WNT5A, and may represent a therapeutic target for metastatic CRC.