Reduced microRNA 375 in colorectal cancer upregulates metadherin-mediated signaling

MicroRNA 429 regulates MMPs expression by modulating TIMP2 expression in colon cancer cells and inflammatory colitis

BACKGROUND

In a previous study, we found that the expression of microRNA 429 (MIR429) was decreased in dextran sodium sulfate (DSS)-induced mouse colitis tissues.

OBJECTIVE

In this study, we aimed to investigate the interaction of MIR429 with TIMP metallopeptidase inhibitor 2 (TIMP2), one of its candidate target genes, in human colorectal cancer (CRC) cells and DSS-induced mouse colitis tissues.

METHODS

A luciferase reporter system was used to confirm the effect of MIR429 on TIMP2 expression. The expression levels of MIR429 and target genes in cells or tissues were evaluated through quantitative RT-PCR, western blotting, or immunohistochemistry.

RESULTS

We found that the expression level of MIR429 was downregulated in human CRC tissues, and also showed that TIMP2 is a direct target gene of MIR429 in CRC cell lines. Furthermore, MIR429 regulate TIMP2-mediated matrix metallopeptidases (MMPs) expression in CRC cells. We also generated cell lines stably expressing MIR429 in CRC cell lines and showed that MIR429 regulates the expression of MMPs by mediating TIMP2 expression. In addition to human CRC tissues, we found that TIMP2 was highly expressed in mouse colitis tissues and human ulcerative colitis (UC) tissues.

CONCLUSIONS

Our findings suggest that the expression of endogenous MIR429 was reduced in human CRC tissues and colitis, leading to upregulation of its target gene TIMP2. The upregulation of TIMP2 by decreased MIR429 expression in CRC tissues and inflamed tissues suggests that it may affect extracellular matrix (ECM) remodeling through downregulation of MMPs. Therefore, MIR429 may have therapeutic value for human CRC and colitis.

Linc00239 Promotes Colorectal Cancer Development via MicroRNA-182-5p/Metadherin Axis

Long non-coding RNAs (lncRNAs) are associated with colorectal cancer (CRC); however, CRC-related linc00239 functions have not been fully elucidated. Prognostic analysis of patients with CRC with linc00239 overexpression was performed using data from The Cancer Genome Atlas database. Cell Counting Kit-8 and Transwell were used to determine linc00239 functions for CRC cells. The lncRNA-miRNA-mRNA interaction network was used to screen target miRNAs and mRNAs regulated by linc00239. Quantitative real-time polymerase chain reaction and western blotting were used to confirm the miRNA and mRNA expression. Furthermore, a miRNA inhibitor was transfected into CRC cells, and cell function was evaluated. Results indicated a high linc00239 expression in the tumor tissue of patients with CRC. Transfection of linc00239 siRNA into SW480 and LOVO cells decreased cell proliferation, cell migration, and invasion. MiR-182-5p/metadherin (MTDH) axis is a downstream pathway of linc00239. MTDH expression, the activity of cell proliferation, migration, and invasion, which were suppressed by linc00239 siRNA, were partially attenuated when linc00239 siRNA and miR-182-5p inhibitor were co-transfected into the CRC cells. Furthermore, miR-182-5p expression was decreased and MTDH expression was promoted in CRC tissues. Altogether, linc00239 may promote CRC development through the miR-182-5p/MTDH axis.

MicroRNA 452 regulates SHC1 expression in human colorectal cancer and colitis

BACKGROUND

Human microRNA 452 (MIR452) has been linked to both colorectal cancer (CRC) tissues and dextran sulfate sodium (DSS)-induced colitis.

OBJECTIVE

We analyzed the correlation between MIR452 and its putative target gene in human CRC cells and in mouse colitis tissues.

METHODS

Luciferase reporter assay confirmed that Src homologous and collagen adaptor protein 1 (SHC1) is a direct target of MIR452. Furthermore, the expression of proteins or mRNA was assessed by immunohistochemical analysis, Western blot, or quantitative RT-PCR (qRT-PCR).

RESULTS

We found that MIR452 has a potential binding site at 3'-UTR of SHC1. Likewise, MIR452 or siSHC1 transfection dramatically reduced the level of cellular SHC1 in CRC cells. The expression of SHC1 was frequently downregulated in both human CRC tissues and mouse colitis tissues. In CRC cells, we demonstrated that MIR452 regulated the expression of genes involved in the SHC1-mediated KRAS-MAPK signal transduction pathways.

CONCLUSION

These findings suggest a potential defense mechanism in which MIR452 regulation of the adaptor protein SHC1 maintains cellular homeostasis during carcinogenesis or chronic inflammation. Therefore, MIR452 may have therapeutic value for human early-stage CRC and colitis.

MicroRNA 133A Regulates Cell Proliferation, Cell Migration, and Apoptosis in Colorectal Cancer by Suppressing CDH3 Expression

MicroRNAs are endogenous, non-coding RNA that play an essential role in colorectal carcinoma (CRC) pathogenesis by targeting specific genes. This research aimed to determine and validate the target genes of the MIR133A associated with CRC. We verified that cadherin 3 (CDH3) is the direct target gene of MIR133A using a luciferase reporter assay, quantitative RT-PCR, and western blot analyses. CDH3 mRNA and protein expression were reduced significantly in CRC cells after transfection with MIR133A or siCDH3. We also verified that MIR133A regulated CDH3-mediated catenin, matrix metalloproteinase, apoptosis, and the epithelial-mesenchymal transition (EMT) pathway. Knockdown of CDH3 in CRC cell lines by siCDH3 produced similar results. Compared with adjacent non-tumor tissues, CDH3 protein expression was upregulated in CRC tissues, which is further confirmed by immunohistochemistry. Additionally, molecular and functional studies revealed that cell viability, migration, and colony formation were significantly reduced, and apoptosis was increased in CRC cell lines transfected with MIR133A or siCDH3. Our results suggest that MIR133A regulates CDH3 expression in human CRC.

Recent advances in the diagnostic and therapeutic roles of microRNAs in colorectal cancer progression and metastasis

Colorectal cancer (CRC) is the third most common malignancy in the world and one of the leading causes of cancer death; its incidence is still increasing in most countries. The early diagnostic accuracy of CRC is low, and the metastasis rate is high, resulting in a low survival rate of advanced patients. MicroRNAs (miRNAs) are a small class of noncoding RNAs that can inhibit mRNA translation and trigger mRNA degradation, and can affect a variety of cellular and molecular targets. Numerous studies have shown that miRNAs are related to tumour progression, immune system activity, anticancer drug resistance, and the tumour microenvironment. Dysregulation of miRNAs occurs in a variety of malignancies, including CRC. In this review, we summarize the recent research progress of miRNAs, their roles in tumour progression and metastasis, and their clinical value as potential biomarkers or therapeutic targets for CRC. Furthermore, we combined the roles of miRNAs in tumorigenesis and development with the therapeutic strategies of CRC patients, which will provide new ideas for the diagnosis and treatment of CRC.

Classical Angiogenic Signaling Pathways and Novel Anti-Angiogenic Strategies for Colorectal Cancer

Although productive progress has been made in colorectal cancer (CRC) researchs, CRC is the second most frequent type of malignancy and the major cause of cancer-related death among gastrointestinal cancers. As angiogenesis constitutes an important point in the control of CRC progression and metastasis, understanding the key signaling pathways that regulate CRC angiogenesis is critical in elucidating ways to inhibit CRC. Herein, we comprehensively summarized the angiogenesis-related pathways of CRC, including vascular endothelial growth factor (VEGF), nuclear factor-kappa B (NF-κB), Janus kinase (JAK)/signal transducer and activator of transcription (STAT), Wingless and int-1 (Wnt), and Notch signaling pathways. We divided the factors influencing the specific pathway into promoters and inhibitors. Among these, some drugs or natural compounds that have antiangiogenic effects were emphasized. Furthermore, the interactions of these pathways in angiogenesis were discussed. The current review provides a comprehensive overview of the key signaling pathways that are involved in the angiogenesis of CRC and contributes to the new anti-angiogenic strategies for CRC.

MIR133A regulates cell proliferation, migration, and apoptosis by targeting SOX9 in human colorectal cancer cells

The human microRNA 133A (MIR133A) was identified as a CRC-associated miRNA. It was down-regulated in human CRC tissues. We identified the putative MIR133A1 and A2 target genes by comparing the transcriptome analysis data of MIR133A1 and A2 knock-in cells with the candidate MIR133A target genes predicted by bioinformatics tools. We identified 29 and 33 putative MIR133A and A2 direct target genes, respectively. Among them, we focused on the master transcription regulator gene SRY-box transcription factor 9 (SOX9), which exhibits a pleiotropic role in cancer. We confirmed that SOX9 is a direct target gene of MIR133A by luciferase reporter assay, quantitative RT-PCR, and western blot analysis. Overexpression of MIR133A in CRC cell lines significantly decreased SOX9 and its downstream PIK3CA-AKT1-GSK3B-CTNNB1 and KRAS-BRAF-MAP2K1-MAPK1/3 pathways and increased apoptosis. Furthermore, functional studies reveal that cell proliferation, colony formation, and migration ability were significantly decreased by MIR133A-overexpressed CRC cell lines. Knockdown of SOX9 in CRC cell lines by SOX9 gene silencing showed similar results. We also used a xenograft model to show that MIR133A overexpression suppresses tumor growth and proliferation. Our results suggest that MIR133A regulates cell proliferation, migration, and apoptosis by targeting SOX9 in human colorectal cancer.

Metadherin (AEG-1/MTDH/LYRIC) expression: Significance in malignancy and crucial role in colorectal cancer

Metadherin (AEG-1/MTDH/LYRIC) is a 582-amino acid transmembrane protein, encoded by a gene located at chromosome 8q22, and distributed throughout the cytoplasm, peri-nuclear region, nucleus, and nucleolus as well as the endoplasmic reticulum (ER). It contains several structural and interacting domains through which it interacts with transcription factors such as nuclear factor-κB (NF-κB), promyelocytic leukemia zinc finger (PLZF), staphylococcal nuclease domain containing 1 (SND1) and lung homing domain (LHD). It is regulated by miRNAs and mediates its oncogenic function via activation of cell proliferation, survival, migration and metastasis, as well as, angiogenesis and chemoresistance via phosphatidylinositol-3-kinase/AKT (PI3K/AKT), NF-κB, mitogen-activated protein kinase (MAPK) and Wnt signaling pathways. In this chapter, metadherin is reviewed highlighting its role in mediating growth, metastasis and chemoresistance in colorectal cancer (CRC). Metadherin, as well as its variants, and antibodies are associated with CRC progression, poorer prognosis, decreased survival and advanced clinico-pathology. The potential of AEG-1/MTDH/LYRIC as a diagnostic and prognostic marker as well as a therapeutic target in CRC is explored.

MicroRNA 452 regulates IL20RA-mediated JAK1/STAT3 pathway in inflammatory colitis and colorectal cancer

OBJECTIVE

MicroRNAs are a class of small, non-coding RNAs that play a key role in several biological and molecular processes, including tumorigenesis. We previously identified that MIR452 is upregulated in both colorectal cancer (CRC) and colitis. However, the functional mechanisms of MIR452 and its target genes in CRC and colitis are not well understood. So, we hypothesize that MIR452 can influence CRC and DSS-induced colitis model through the regulation of IL20RA and its downstream JAK-STATs signaling pathway.

METHODS

We used a luciferase reporter assay to confirm the effect of MIR452 on IL20RA expression. The protein and mRNA expression of a target gene and its associated molecules were measured by western blot, quantitative RT-PCR, and immunohistochemistry.

RESULTS

We found that the IL20RA was a direct target gene of MIR452. Overexpression of MIR452 in CRC cell lines significantly decreased IL20RA and its downstream Janus kinase 1 (JAK1), Signal transducer and activator of transcription 1 (STAT1) and STAT3. Knockdown of IL20RA in CRC cell lines by IL20RA gene silencing also decreased the expression of IL20RA, JAK1, and STAT3, but not of STAT1.

CONCLUSION

Our results suggest that MIR452 regulates STAT3 through the IL20RA-mediated JAK1 pathway, but not STAT1. Overall, MIR452 acts as tumor suppressor in human CRC and in a mouse colitis model. These findings suggest that MIR452 is a promising therapeutic target in the treatment of cancer and colitis.

MicroRNA 452 regulates ASB8, NOL8, and CDR2 expression in colorectal cancer cells

BACKGROUND

MicroRNAs play important roles in the pathogenesis of human diseases by regulating target gene expression in specific cells or tissues. Previously, we identified microRNA 452 (MIR452), which was specifically up-regulated in early stage human colorectal cancer (CRC) tissue.

OBJECTIVE

The current study aims to identify and verify the target genes of MIR452 associated with CRC.

METHODS

A luciferase reporter system was used to confirm the effect of MIR452 on ASB8, NOL8, and CDR2 expression. The expression levels of MIR452 and the target genes were evaluated by quantitative RT-PCR (qRT-PCR) and western blotting.

RESULTS

We verified the association between MIR452 and three genes, ASB8, NOL8, and CDR2, and showed that their transcripts were down-regulated by MIR452. Up-regulated MIR452 also down-regulated ASB8, NOL8, and CDR2 mRNA and protein levels in CRC cells. CDR2 protein expression was decreased in CRC tissues compared to adjacent non-tumor tissues.

CONCLUSIONS

These results suggest that ASB8, NOL8, and CDR2 were target genes of MIR452 in CRC cells and that up-regulated MIR452 in CRC tissue regulated ASB8, NOL8, and CDR2 expression during colorectal carcinogenesis.