miR-27a induced by colon cancer cells in HLECs promotes lymphangiogenesis by targeting SMAD4

Recent advances microRNAs and metabolic reprogramming in colorectal cancer research

Colorectal cancer (CRC) is a cancer with the highest incidence and mortality. Alteration of gene expression is the main pathophysiological mechanism of CRC, which results in disturbed signaling pathways and cellular metabolic processes. MicroRNAs are involved in almost all pathophysiological processes and are correlative with colorectal cancer metabolism, proliferation, and chemotherapy resistance. Metabolic reprogramming, an important feature of cancer, is strongly correlative with the development and prognosis of cancers, including colorectal cancer. MicroRNAs can target enzymes involved in metabolic processes, thus playing a regulatory role in tumor metabolism. The disorder of the signaling pathway is another characteristic of tumor, which induces the occurrence and proliferation of tumors, and is closely correlative with the prognosis and chemotherapy resistance of tumor patients. MicroRNAs can target the components of the signaling pathways to regulate their transduction. Understanding the function of microRNAs in the occurrence and proliferation of CRC provides novel insights into the optimal treatment strategies, prognosis, and development of diagnosis in CRC. This article reviews the relationship between CRC and microRNA expression and hopes to provide new options for the diagnosis and treatment of CRC.

MiR-27a as a diagnostic biomarker and potential therapeutic target in systemic sclerosis

Systemic sclerosis (SSc) or scleroderma is a multiorgan rheumatoid disease characterized by skin tightening or organ dysfunction due to fibrosis, vascular damage, and autoimmunity. No specific cause has been discovered for this illness, and hence no effective treatment exists for it. On the other hand, due to the lack of diagnostic biomarkers capable of effectively and specifically differentiating the patients, early diagnosis has not been possible. Due to their potent regulatory roles in molecular pathways, microRNAs are among the novel candidates for the diagnosis and treatment of diseases like SSc. MiR-27a is a microRNA known for its role in the pathogenesis of fibrosis and cancer, both of which employ similar signaling pathways; hence we hypothesized that Mir-27a could be dysregulated in the blood of individuals affected by SSc and it might be useful in the diagnosis or treatment of this disease. Blood was collected from 60 SSc patients (30 limited and 30 diffuse) diagnosed by a rheumatologist according to ACR/AULAR criteria; following RNA isolation and cDNA synthesis; real-time qPCR was performed on the samples using Taq-Man probes and data were analyzed by the ΔΔCT method. Also, potential targets of miR-27a were evaluated using bioinformatics. It was revealed that miR-27a was significantly down-regulated in SSc patients in comparison to healthy individuals, but there was no difference in miR-27 expression between limited and diffused SSc patients. Besides, miR-27a was found to target several contributing factors to SSc. It seems that miR-27a has a protective role in SSc, and its downregulation could result in the disease's onset. Based on bioinformatics analyses, it is speculated that miR-27a likely targets factors contributing to the pathogenesis of SSc, which are elevated upon the downregulation of miR-27a; hence, miR-27a mimics could be considered as potential therapeutic agents for the treatment of SSc in future studies. Since no difference was observed between limited and diffuse patient groups, it is unlikely that this microRNA has a role in disease progression. According to ROC analysis of qPCR data, miR-27a could be employed as a valuable diagnostic biomarker for SSc.

Serum-derived extracellular vesicles mediate Smad4 expression through shuttling microRNA-27a in the progression of laryngeal squamous cell carcinoma

Serum-derived extracellular vesicles (EVs) containing non-coding RNAs have been indicated to serve as diagnostic and prognostic biomarkers for laryngeal squamous cell carcinoma (LSCC), while their functional role remains to be explored. Here, we summarize the possible mechanism explaining the laryngeal carcinogenesis and the associated changes with the involvement of extracellular microRNA (miR)-27a from serum of LSCC patients. Serum-derived EVs from LSCC patients were found to increase the proliferative activity and decreased the apoptotic activity of LSCC cells. miRNA microarrays revealed that miR-27a expression was elevated after EV treatment. miR-27a expression was elevated in LSCC tissues and predicted a poor prognosis for patients. Downregulation of miR-27a inhibited the effect of EVs to reduce the activity of LSCC cells in vitro and to suppress tumor development in vivo. miR-27a targeted SMAD family member 4 (Smad4) to mediate the Wnt/β-catenin pathway, which was induced under the influence of EVs. Smad4 was downregulated in LSCC tissues, and simultaneous overexpression of miR-27a and Smad4 resulted in reduced cell activity and tumorigenicity. In conclusion, serum-derived EVs support the laryngeal carcinogenesis at least partially via transferring miR-27a. miR-27a targets Smad4 and is a biomarker to predict LSCC prognosis.

MicroRNAs Are Key Molecules Involved in the Gene Regulation Network of Colorectal Cancer

Colorectal cancer (CRC) is one of the most common types of cancer and one of the leading causes of mortality worldwide. MicroRNAs (miRNAs) play central roles in normal cell maintenance, development, and other physiological processes. Growing evidence has illustrated that dysregulated miRNAs can participate in the initiation, progression, metastasis, and therapeutic resistance that confer miRNAs to serve as clinical biomarkers and therapeutic targets for CRC. Through binding to the 3′-untranslated region (3′-UTR) of target genes, miRNAs can lead to target mRNA degradation or inhibition at a post-transcriptional level. During the last decade, studies have found numerous miRNAs and their potential targets, but the complex network of miRNA/Targets in CRC remains unclear. In this review, we sought to summarize the complicated roles of the miRNA-target regulation network (Wnt, TGF-β, PI3K-AKT, MAPK, and EMT related pathways) in CRC with up-to-date, high-quality published data. In particular, we aimed to discuss the downstream miRNAs of specific pathways. We hope these data can be a potent supplement for the canonical miRNA-target regulation network.

Angioregulatory role of miRNAs and exosomal miRNAs in glioblastoma pathogenesis

Glioblastoma (GB) is a highly aggressive cancer of the central nervous system, occurring in the brain or spinal cord. Many factors such as angiogenesis are associated with GB development. Angiogenesis is a procedure by which the pre-existing blood vessels create new vessels that play an essential role in health and disease, including tumors. Also, angiogenesis is one of the significant factors thought to be responsible for treatment resistance in many tumors, including GB. Hence, an improved understanding of the molecular processes underlying GB angiogenesis will pave the way for developing potential new treatments. Recently, it has been found that microRNAs (miRNAs) and exosomal miRNAs have a crucial role in inducing or inhibiting the angiogenesis process in GB development. A better knowledge of the miRNA's regulation pathway in the angiogenesis process in cancer offers unique mechanistic insight into the mechanism of tumor-associated neovascularization. Because of advancements in miRNA characterization and delivery methods, miRNAs can also be employed in clinical settings as potential biomarkers for anti-angiogenic treatment response as well as therapies targeting tumor angiogenesis. The recent finding and insights about miRNAs' angioregulatory role and exosomal miRNAs in GB are provided throughout the review. Also, we discuss the new concept of miRNAs-based therapies for GB in the future.

Role of miR-27a in the regulation of cellular function via the inhibition of MAP2K4 in patients with asthma

Asthma is a respiratory disease with a clinically high incidence, and repeated attacks of asthma severely affect the quality of life and even pose a threat to health, leading to severe burdens on families and even the society. A thorough understanding of the pathogenesis of asthma is essential for the prevention and treatment of asthma. This study aimed to examine the effect of the microRNA miR-27a on asthma and its relationship with mitogen activated protein kinase 4 (MAP2K4). Patients with asthma admitted to our hospital from August 2016 to August 2018 and healthy participants in the same period were included in this prospective analysis. The mRNA expression levels of miR-27a and MAP2K4 in peripheral blood were determined. Airway smooth muscle cells (ASMCs) were used to study the effects of miR-27a and MAP2K4 on cell biological behavior. The relationship between miR-27a and MAP2K4 was verified using dual-luciferase reporter assay. miR-27a expression was increased and MAP2K4 mRNA expression was decreased in asthma (P < 0.05). Increasing miR-27a expression and inhibiting MAP2K4 expression could enhance the activity of ASMCs, whereas inhibiting miR-27a expression and increasing MAP2K4 expression had the opposite effect (P < 0.05). Dual-luciferase reporter assay results showed that the fluorescence activity of MAP2K4-wild type was inhibited by increased miR-27a expression (P < 0.05). miR-27a promotes the proliferation and invasion of ASMCs by targeting MAP2K4 and is involved in the occurrence of asthma.

Role of Extracellular Vesicles on Cancer Lymphangiogenesis and Lymph Node Metastasis

Lymph node metastasis (LNM) of tumors is an established indicator of poor prognosis in patients. Tumor-associated lymphangiogenesis is a key step in LNM and has gained much attention. However, currently, there is no anti-tumor lymphangiogenesis drug used in clinical practice. Recently, studies on extracellular vesicles (EVs) have shown that different types of cells in the tumor microenvironment can release EVs that encapsulate a variety of molecules, including proteins, nucleic acids, and metabolites. Lymph endothelial cells (LECs) regulate tumor lymphangiogenesis through the uptake of EVs packed with different biologically active contents. In this review, we will discuss the possible mechanisms by which EVs participate in the regulation of tumor-associated lymphangiogenesis and LNM, summarize the potential value of EVs that can be used as biomarkers for the determination of tumor LNM, and indicate the potential anti-tumor lymphangiogenesis therapy.

Downregulation of HOXC6 by miR-27a ameliorates gefitinib resistance in non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is a major type of lung cancer. Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs), represented by gefitinib (Gef), are targeted drugs used for the treatment of NSCLC. However, NSCLC patients often develop resistance to tyrosine kinase inhibitors, which limits their efficacy. Homeobox gene HOXC6 is dysregulated in many cancers and contributes to chemoresistance in cancer cells. However, the role and mechanism of HOXC6 in the development of Gef resistance in NSCLC remains unclear. In the present study, we found that HOXC6 was highly expressed in Gef-resistant NSCLC cells. Further experiments showed that silencing of HOXC6 ameliorated Gef resistance in PC9/G cells whereas overexpression of HOXC6 promoted Gef resistance in PC9 cells. HOXC6 influenced Gef sensitivity in NSCLC cells by regulating cell proliferation, colony formation, cell apoptosis, cell cycle, cell mobility and other related signaling molecules or pathways. HOXC6 was also found to be a direct target of miR-27a. As expected, overexpression of miR-27a ameliorated Gef resistance by inhibiting HOXC6 expression in vitro and in vivo. Clinical analysis revealed that high HOXC6 levels and low miR-27a levels were significantly correlated with more malignant clinical features and poorer survival of NSCLC patients. In summary, the present study demonstrates that HOXC6 may be a potential therapeutic target for overcoming Gef resistance in NSCLC patients. A combination of Gef and miR-27a agomirs may be an effective intervention for Gef-resistant NSCLC.

miR-27a acts as an oncogene to regulate endometrial cancer progression by targeting USP46

Endometrial cancer (EC) ranks as the fourth most common diagnosed cancer type in females worldwide. MicroRNAs (miRNAs) are important regulators with crucial roles in regulating diverse biologic processes, including tumor initiation and progression. Previous studies have demonstrated that miR-27a was correlated with the tumorigenesis of various cancers. However, its expression and biologic role in EC remain to be determined. This study aimed to clarify whether miR-27a acts as an oncogene in endometrial cancer (EC) by downregulating ubiquitin specific peptidase 46 (USP46). Expression of miR-27a was measured by qRT-PCR, and the results demonstrated that miR-27a was upregulated in EC cell lines compared to normal cell lines. Cell counting kit-8 (CCK-8) and wound-healing assays demonstrated that overexpression of miR-27a significantly promoted cell proliferation and migration. Online prediction algorithm and dual luciferase activity reporter assay revealed that USP46 acts as a direct target of miR-27a. USP46 expression was downregulated in EC cell lines during miR-27a overexpression. Collectively, our results indicated that miR-27a targets USP46 to promote EC cell proliferation and migration, suggesting an oncogene role of miR-27a in EC.

Angioregulatory microRNAs in breast cancer: Molecular mechanistic basis and implications for therapeutic strategies

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Cancer-associated angiogenesis is a fundamental process in tumor growth and metastasis.

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Angioregulatory miRNA–target gene interaction is not only involved in sprouting vessels of breast tumors but also, trans-differentiation of breast cancer cells to endothelial cells in a process termed vasculogenic mimicry.

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Successful targeting of tumor angiogenesis is still a missing link in the treatment of Breast cancer (BC) due to the low effectiveness of anti-angiogenic therapies in this cancer.

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Response to anti-angiogenic therapeutics are controlled by a miRNAs, so the identification of interaction networks of miRNAs–targets can be applicable in determining anti-angiogeneic therapy and new biomarkers in BC.

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Angioregulatory miRNAs in breast cancer cells and their microenvironment have therapeutic potential in cancer treatment.

Background

Cancer-associated angiogenesis is a fundamental process in tumor growth and metastasis. A variety of signaling regulators and pathways contribute to establish neovascularization, among them as small endogenous non-coding RNAs, microRNAs (miRNAs) play prominent dual regulatory function in breast cancer (BC) angiogenesis.

Aim of Review

This review aims at describing the current state-of-the-art in BC angiogenesis-mediated by angioregulatory miRNAs, and an overview of miRNAs dysregulation association with the anti-angiogenic response in addition to potential clinical application of miRNAs-based therapeutics.

Key Scientific Concepts of Review

Angioregulatory miRNA–target gene interaction is not only involved in sprouting vessels of breast tumors but also, trans-differentiation of BC cells to endothelial cells (ECs) in a process termed vasculogenic mimicry. Using canonical and non-canonical angiogenesis pathways, the tumor cell employs the oncogenic characteristics such as miRNAs dysregulation to increase survival, proliferation, oxygen and nutrient supply, and treatment resistance. Angioregulatory miRNAs in BC cells and their microenvironment have therapeutic potential in cancer treatment. Although, miRNAs dysregulation can serve as tumor biomarker nevertheless, due to the association of miRNAs dysregulation with anti-angiogenic resistant phenotype, clinical benefits of anti-angiogenic therapy might be challenging in BC. Hence, unveiling the molecular mechanism underlying angioregulatory miRNAs sparked a booming interest in finding new treatment strategies such as miRNA-based therapies in BC.

MAP17 contributes to non-small cell lung cancer progression via suppressing miR-27a-3p expression and p38 signaling pathway

PROBLEM AND AIM

The overexpression of MAP17 has been reported in various human carcinomas. However, its molecular mechanism in non-small cell lung cancer (NSCLC) has not been fully understood. Our study aimed to reveal the molecular mechanism of NSCLC that involved MAP17 and identify its target miRNA.

METHODS

RT-qPCR and immunoblot assays were conducted to measure the expression of mRNA and protein in NSCLC tissues and cell lines. Meanwhile, the A549 cells (an NSCLC cell line) were randomly assigned to the MAP17 overexpression group, the MAP17 knockdown group and negative control group to study the roles of MAP17 in cell viability, cell proliferation, migration, invasion, and apoptosis by performing Trypan blue exclusion, MTT, colony formation, transwell, wound healing and flow-cytometric apoptosis assays. The luciferase reporter assay was conducted to confirm the target relationship between MAP17 and miR-27a-3p.

RESULTS

The upregulation of MAP17 mRNA and protein was observed in NSCLC tissues and cell lines. In vitro, the positive roles of MAP17 on cell viability, migration, and invasion were confirmed in A549 cells. It was also found that MAP17 could inhibit cell apoptosis by suppressing the activation of the p38 pathway. This research eventually proved the target relationship between MAP17 and miR-27a-3p, and that miR-27a-3p reversed the effects of MAP17 in A549 cells by directly targeting MAP17.

CONCLUSIONS

MAP17 plays an oncogenic role in NSCLC by suppressing the activation of the p38 pathway. Apart from that, the miR-27a-3p can inhibit the expression of MAP17 to suppress the NSCLC progression.

The Roles of Non-Coding RNAs in Tumor-Associated Lymphangiogenesis

Simple Summary

The lymphatic system plays key roles in the bodies’ defence against disease, including cancer. The expansion of this system is termed lymphangiogenesis and it is orchestrated by factors and conditions within the microenvironment. One approach to prevent cancer progression is by interfering with these microenvironment factors that promote this process and that facilitate the spread of cancer cells to distant organs. One of these factors are non-coding RNAs. This review will summarize recent findings of the distinct roles played by non-coding RNAs in the lymphatic system within normal tissues and tumours. Understanding the mechanisms involved in this process can provide new avenues for therapeutic intervention for inhibiting the spread of cancer.

Abstract

Lymphatic vessels are regarded as the ”forgotten” circulation. Despite this, growing evidence has shown significant roles for the lymphatic circulation in normal and pathological conditions in humans, including cancers. The dissemination of tumor cells to other organs is often mediated by lymphatic vessels that serve as a conduit and is often referred to as tumor-associated lymphangiogenesis. Some of the most well-studied lymphangiogenic factors that govern tumor lymphangiogenesis are the vascular endothelial growth factor (VEGF-C/D and VEGFR-2/3), neuroplilin-2 (NRP2), fibroblast growth factor (FGF), and hepatocyte growth factor (HGF), to name a few. However, recent findings have illustrated that non-coding RNAs are significantly involved in regulating gene expression in most biological processes, including lymphangiogenesis. In this review, we focus on the regulation of growth factors and non-coding RNAs (ncRNAs) in the lymphatic development in normal and cancer physiology. Then, we discuss the lymphangiogenic factors that necessitate tumor-associated lymphangiogenesis, with regards to ncRNAs in various types of cancer. Understanding the different roles of ncRNAs in regulating lymphatic vasculature in normal and cancer conditions may pave the way towards the development of ncRNA-based anti-lymphangiogenic therapy.

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.

Extracellular Vesicles (EVs) and Pancreatic Cancer: From the Role of EVs to the Interference with EV-Mediated Reciprocal Communication

Pancreatic cancer is malignant and the seventh leading cause of cancer-related deaths worldwide. However, chemotherapy and radiotherapy are—at most—moderately effective, indicating the need for new and different kinds of therapies to manage this disease. It has been proposed that the biologic properties of pancreatic cancer cells are finely tuned by the dynamic microenvironment, which includes extracellular matrix, cancer-associated cells, and diverse immune cells. Accumulating evidence has demonstrated that extracellular vesicles (EVs) play an essential role in communication between heterogeneous subpopulations of cells by transmitting multiplex biomolecules. EV-mediated cell–cell communication ultimately contributes to several aspects of pancreatic cancer, such as growth, angiogenesis, metastasis and therapeutic resistance. In this review, we discuss the role of extracellular vesicles and their cargo molecules in pancreatic cancer. We also present the feasibility of the inhibition of extracellular biosynthesis and their itinerary (release and uptake) for a new attractive therapeutic strategy against pancreatic cancer.

miR-503-5p inhibits colon cancer tumorigenesis, angiogenesis, and lymphangiogenesis by directly downregulating VEGF-A

MicroRNAs (miRNAs) are considered important in the pathogenesis of colon cancer. But the mechanism of their role in colon cancer is still largely unknown. Here, we aimed to explore the function of miR-503-5p in the pathogenesis of colon cancer. This study analyzed miRNA microarray of colon cancer. Then, we performed EdU, CCK-8, flow cytometry, Transwell invasion assays and in vivo assays to explore the exact role of miR-503-5p in colon cancer. We observed considerable downregulation of miR-503-5p expression in colon cancer cells and tissues and significant correlation with the TNM stage, differentiation grade and lymph node metastasis of colon cancer. Overexpression of miR-503-5p promoted the apoptosis and G1 arrest of colon cancer cells, and inhibited migration, proliferation, invasion and colony formation. Interestingly, ectopic miR-503-5p overexpression could significantly inhibit vascular endothelial growth factor (VEGF)-A expression and reduce the activity of a luciferase reporter containing the VEGF-A 3'-untranslated region. Furthermore, overexpressed miR-503-5p in human umbilical vein endothelial cells (HUVECs) and colon cancer cells resulted in lower expression levels of VEGFR-2, and subsequently inhibited AKT signaling pathway. Additionally, overexpression of miR-503-5p suppressed both lymphangiogenesis and angiogenesis in vivo and significantly inhibited the tumorigenicity of HT-29 cells in nude mice. In summary, our study shows downregulation of miR-503-5p at least partially contributes to the tumorigenesis of colon cancer through modulating the angiogenesis and lymphangiogenesis by targeting VEGF-A while stimulating AKT signaling pathways. Therapeutic strategies to restore miR-503-5p in colon cancer could be useful to inhibit tumor progression.

DKK2 blockage-mediated immunotherapy enhances anti-angiogenic therapy of Kras mutated colorectal cancer

There are limited options for targeted therapies for colorectal cancer (CRC). Anti-EGFR therapy is limited to CRC without KRAS mutations. Even worse, most of CRC are refractory to currently immune checkpoint blockade. DKK2, which is upregulated in CRC, was recently found to suppress host immune responses, and its blockage effectively impeded tumor progression in benign genetic CRC models in our previous study. Here, our recent study demonstrated that in human CRC tumor samples expressing high levels of DKK2, DKK2 blockade caused stronger activation of tumor infiltrating CD8⁺ T cells in ex vivo culture. Intriguingly, we observed a correlation of high DKK2 expression with increased lymph node metastasis prevalence in these CRC patients as well. Furthermore, in a mouse genetic CRC model with mutations in APC and KRAS, which more closely mimics advanced human CRC, we confirmed the tumor inhibitory effect of DKK2 blockade, which significantly retarded tumor progression and extended survival, with increased immune effector cell activation and reduced angiogenesis. Based on this, we performed a combined administration of DKK2 blockade with sub-optimal anti-VEGFR treatment and observed a synergetic effect on suppressing tumor angiogenesis and progression, as well as extending survival, better than those of every single therapy. Thus, this study provides further evidence for the potential therapeutic application of DKK2 blockade in the clinical treatment of human CRC.

Angioregulatory microRNAs in Colorectal Cancer

Colorectal cancer (CRC) is one of the leading causes of cancer mortality. Angiogenesis is a rate-determining step in CRC development and metastasis. The balance of angiogenic and antiangiogenic factors is crucial in this process. Angiogenesis-related genes can be regulated post-transcriptionally by microRNAs (miRNAs) and some miRNAs have been shown to shuttle between tumor cells and the tumor microenvironment (TME). MiRNAs have context-dependent actions and can promote or suppress angiogenesis dependent on the type of cancer. On the one hand, miRNAs downregulate anti-angiogenic targets and lead to angiogenesis induction. Tumor suppressor miRNAs, on the other hand, enhance anti-angiogenic response by targeting pro-angiogenic factors. Understanding the interaction between these miRNAs and their target mRNAs will help to unravel molecular mechanisms involved in CRC progression. The aim of this article is to review the current literature on angioregulatory miRNAs in CRC.

The Role of TGF-β Signaling Regulatory MicroRNAs in the Pathogenesis of Colorectal Cancer

Colorectal cancer (CRC) is one of the most common cancers globally and is associated with a high mortality rate. The transforming growth factor beta (TGF-β) signaling pathway plays an important role in normal intestinal tissue function, but has also been implicated in the development of CRC. MicroRNAs (miRNAs) have also recently emerged as important regulators of cancer development and progression. They act by targeting multiple signaling pathways including the TGF-β signaling pathway. There is growing evidence demonstrating that miRNAs target various components of the TGF-β signaling pathway, including TGF-β1, TGF-β2, regulatory SMADs (SMAD1, 2, 3, 5 and 9), co-mediator SMAD4, inhibitory SMADs (SMAD6 and 7) and the TGF-β receptors, and thereby alter the proliferation and migration of CRC cells. In this review, we summarize the data concerning the interaction between TGF-β signaling pathway and miRNAs with the aim to better understanding the CRC molecular mechanisms and hence better management of this disease.

Non-coding RNAs as Regulators of Lymphangiogenesis in Lymphatic Development, Inflammation, and Cancer Metastasis

Non-coding RNAs (ncRNAs), which do not encode proteins, have pivotal roles in manipulating gene expression in development, physiology, and pathology. Emerging data have shown that ncRNAs can regulate lymphangiogenesis, which refers to lymphatics deriving from preexisting vessels, becomes established during embryogenesis, and has a close relationship with pathological conditions such as lymphatic developmental diseases, inflammation, and cancer. This review summarizes the molecular mechanisms of lymphangiogenesis in lymphatic development, inflammation and cancer metastasis, and discusses ncRNAs' regulatory effects on them. Therapeutic targets with regard to lymphangiogenesis are also discussed.

MicroRNA-27a (miR-27a) in Solid Tumors: A Review Based on Mechanisms and Clinical Observations

MicroRNAs (miRNAs) are a family of highly conserved, non-coding single-stranded RNAs transcribed as ~70 nucleotide precursors to an 18–22 nucleotide product (1). miRNAs can silence their homologous target genes at the post-transcriptional level, and these genes have been revealed to play an important role in tumorigenesis, invasion and metastasis (2). MicroRNA-27a (miR-27a), transcripted by miR-27a gene, has proved to implicate with many kinds of solid tumors, showing potential as a useful biomarker or drug target for clinical application. However, even though miR-27a has been reported in many cancers, the mechanism and signal pathways of miR-27 in oncogenesis, invasion, and metastasis are still obscure. Moreover, recent studies show that miR-27a pays an important role in epithelial-mesenchymal-transition, regulating tumor immune response, and chemoresistance. In this review, we summarize the current literature, demonstrate the established link between miR-27a and tumorigenesis, and focus on recently identified mechanisms. The review also aims to demonstrate the potential of miR-27a as a diagnostic and/or prognostic biomarker in solid tumors and to discuss the possibilities of targeted therapy and drug design.

Role of TGF-β signaling regulatory microRNAs in the pathogenesis of colorectal cancer

Transforming growth factor β (TGF-β) modulates tumor progression by regulating cell proliferation, apoptosis, metastasis, angiogenesis, and drug resistance. Biological and pharmacological agonists/antagonists, the interplay between intracellular signaling pathways, and microRNAs (miRNAs) control the initiation and activation of the TGF-β signaling pathway. It has been proposed that the expression profiles of tumor suppressor and oncogenic TGF-β miRNAs may be used for the classification, diagnosis, and prognosis of human malignancies. Deregulated miRNAs and aberrant activation of TGF-β signaling are frequently found in human colorectal cancers (CRCs), but a little is known about their mechanisms of action in the development and progression of colorectal carcinoma. This review summarizes the current knowledge of the role of TGF-β signaling regulatory miRNAs in the pathogenesis of CRC for a better understanding and hence better management of this disease.

Significance of miR-27a and miR-31 in early diagnosis and prognosis of colorectal cancer

Clinical significance of micro-ribonucleic acid (miR)-27a and miR-31 in the early diagnosis and prognosis of colorectal cancer were investigated. Forty patients with colorectal malignancy admitted to Xintai People's Hospital from February 2014 to April 2018 were enrolled as the observation group, of which 30 patients were diagnosed via pathological biopsy. Another 40 patients diagnosed with colorectal polyp and receiving surgical treatment were selected as the control group. The relative amount of miR-27a and miR-31 was measured. The relative expression levels of miR-27a and miR-31 in patients were analyzed. The diagnostic sensitivity, specificity and accordance rates of positive miR-27a and miR-31 expression in colorectal cancer were recorded. The correlation of the relative expression levels of miR-27a and miR-31 with the survival time of patients were analyzed. In the observation group, the relative expression levels of miR-27a and miR-31 in patients with lymph node metastasis and distant metastasis were higher than those in patients without lymph node metastasis and distant metastasis (P<0.05). Histological type of patients with non-mucinous carcinoma had increased relative expression levels of miR-27a and miR-31 in comparison with those with mucinous carcinoma (P<0.05). In terms of Duke's grade, the relative expression levels of miR-27a and miR-31 in patients with grade C and D were higher than those in patients with grade A and B (P<0.05). The diagnostic sensitivity, specificity and accordance rate of positive miR-27a expression were lower than those of positive miR-31 expression. The relative expression levels of miR-27a and miR-31 were positively correlated with the survival time of patients (P<0.05). The expression levels of miR-27a and miR-31 are related to distant metastasis and tumor grade of patients with colorectal cancer, and positively associated with the survival time of patients, having high diagnostic value.

HANR promotes lymphangiogenesis of hepatocellular carcinoma via secreting miR-296 exosome and regulating EAG1/VEGFA signaling in HDLEC cells

The long noncoding RNA HANR has been shown to be involved in the progression of hepatocellular carcinoma (HCC). However, the underlying mechanism of HCC-associated long noncoding RNA (HANR)-regulated HCC metastasis and lymphangiogenesis has not been elucidated. RT-qPCR and Western blot methods were utilized to detect the gene expressions. Interaction of HANR with miR-296 was predicted by a bioinformatic program and validated by a dual-luciferase reporter assay. For the functional experiment, a transwell invasion assay was utilized to examine the invasion abilities of HepG2 and Huh-7 cells. The lymphatic vessel formation assay was used to show the HCC-associated lymphatic vessel formation ability of human dermal lymphatic endothelial cells (HDLEC). HANR was shown to directly bind to miR-296, and miR-296 downregulated HANR expression in HepG2 cells. Then, we observed that miR-296 inhibitor transfection in shHANR HCC cells could promote lymphatic vessel formation and invasion of HDLEC cells compared with shHANR HCC cells. EAG1 or VEGFA overexpression in HDLEC cells rescued lymphatic vessel formation and invasion in HDLEC cells coincubated with the medium of HepG2 cells expressing shHANR or miR-296 mimic. Ultimately, HANR knockdown and miR-296 mimic led to a significant decrease in the EAG1 and VEGFA expression levels in HepG2 cells. Here, we reveal a novel molecular mechanism in which the HANR/miR-296/EAG1/VEGF axis is responsible for the lymphangiogenesis of HCC cells. Our findings provide more insights into developing therapeutical or diagnostic methods by targeting HANR.

miRNA and mRNA Integration Network Construction Reveals Novel Key Regulators in Left-Sided and Right-Sided Colon Adenocarcinoma

Background

The distinction between right-sided and left-sided colon adenocarcinoma has recently received considerable. This study aims to identify key MicroRNA (miRNA) and mRNAs in right-sided colon adenocarcinoma (RSCOAD) and left-sided colon adenocarcinoma (LSCOAD) by TCGA integration analysis.

Methods

The miRNA and mRNA expression profiles of a large group of patients with RSCOAD and LSCOAD were obtained from TCGA. The differentially expressed miRNAs (DEmiRNAs) and mRNAs (DEmRNAs) were identified by TCGA integration analysis. The optimal diagnostic miRNA biomarkers for RSCOAD and LSCOAD were identified by Boruta algorithm. We established classification models to distinguish RSCOAD and LSCOAD. Protein-protein interaction (PPI) network analysis, DEmiRNA-DEmRNA interaction analysis, and functional annotation were performed. The expression of selected DEmiRNAs and DEmRNAs was validated by qRT-PCR.

Results

A total of 2534 DEmRNAs (940 downregulated and 1594 upregulated mRNAs) and 54 DEmiRNAs (22 downregulated and 32 upregulated miRNAs) between RSCOAD and LSCOAD were identified. The feature selection procedure was to obtain 22 optimal diagnostic miRNAs biomarkers in RSCOAD compared to LSCOAD. The AUC of the random forests model was 0.869 and the specificity and sensitivity of this model were 79% and 84.6%, respectively. Three DEmiRNAs (hsa-miR-224-5p, hsa-miR-155-5p, and hsa-miR-31-5p) and five DEmRNAs (CXCR4, SMAD4, KRAS, FITM2, and PLAGL2) were identified key DEmiRNAs and DEmRNAs in RSCOAD compared to LSCOAD. The qRT-PCR results of CXCR4, FITM2, TFAP2A, ULBP2, hsa-miR-224-5p, and hsa-miR-155-5p were consistent with our integrated analysis.

Conclusion

A total of three DEmiRNAs (hsa-miR-224-5p, hsa-miR-155-5p, and hsa-miR-31-5p) and five DEmRNAs (CXCR4, SMAD4, KRAS, FITM2, and PLAGL2) may be involved in the pathogenesis of RSCOAD and LSCOAD which may make a contribution for understanding mechanisms and developing therapeutic strategies for RSCOAD and LSCOAD.

The role of TGF-β/SMAD4 signaling in cancer

Transforming growth factor β (TGF-β) signaling pathway plays important roles in many biological processes, including cell growth, differentiation, apoptosis, migration, as well as cancer initiation and progression. SMAD4, which serves as the central mediator of TGF-β signaling, is specifically inactivated in over half of pancreatic duct adenocarcinoma, and varying degrees in many other types of cancers. In the past two decades, multiple studies have revealed that SMAD4 loss on its own does not initiate tumor formation, but can promote tumor progression initiated by other genes, such as KRAS activation in pancreatic duct adenocarcinoma and APC inactivation in colorectal cancer. In other cases, such as skin cancer, loss of SMAD4 plays an important initiating role by disrupting DNA damage response and repair mechanisms and enhance genomic instability, suggesting its distinct roles in different types of tumors. This review lists SMAD4 mutations in various types of cancer and summarizes recent advances on SMAD4 with focuses on the function, signaling pathway, and the possibility of SMAD4 as a prognostic indicator.