MicroRNA-494 within an oncogenic microRNA megacluster regulates G1/S transition in liver tumorigenesis through suppression of mutated in colorectal cancer

MCC in the spotlight: Its dual role in signal regulation and oncogenesis

The mutated in colorectal cancer (MCC) gene is closely associated with the onset and progression of colorectal cancer. MCC plays a critical role in regulating the cell cycle and various signaling pathways and is recognized to inhibit cancer cell proliferation via the β-catenin signaling pathway. β-catenin is a key component of the WNT signaling pathway that influences cell growth, differentiation, survival, and migration, thereby positioning MCC as an important tumor suppressor. Notably, MCC has also been implicated in other cancer types, including lung, liver, and brain cancers. However, the precise mechanisms by which MCC functions in these malignancies remain inadequately understood. Comprehensive investigations into the interactions among MCC, various signaling pathways, and metabolic processes are essential for uncovering the molecular mechanisms of cancer and the pathological features characteristic of different cancer stages. This review presents the structural characteristics of MCC and its cell growth regulation mechanisms and functional roles within tissues, with the aims of enhancing our understanding of the role of MCC in cancer biology and highlighting potential therapeutic strategies targeting this gene.

Longitudinal multi-tracer imaging of hepatocellular carcinoma identifies novel stage- and oncogene-specific changes

BACKGROUND

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related deaths, globally. There is a need for novel biomarkers for early detection and novel, effective targeted therapies. Molecular imaging can faithfully visualize, characterize and quantify specific relevant biological processes.

BASIC PROCEDURE

We performed longitudinal dedicated small-animal positron emission tomography-computed tomography (PET/CT) imaging to analyze changes in glucose metabolism using [18F]fluorodeoxyglucose ([18F]FDG), amino acid turnover with [18F]fluoroethyltyrosine ([18F]FET), and chemokine receptor expression using [68Ga]pentixafor targeting CXCR4, during stages of early tumor development, overt HCC and regression. We used two conditional transgenic mouse models of HCC, driven by clinically relevant oncogenes c-MYC (LT2/MYC) or HRASV12 (LT2/RAS). Conditional doxycycline-regulated mouse models, enable liver-specific oncogene activation or inhibition, leading to liver tumor development and regression, respectively. Correlation of our PET/CT findings with our gene expression and metabolomics data and with histological analyses followed.

MAIN FINDINGS

We show PET/CT identifies HCC stage-specific and oncogene-specific molecular changes that may serve as potential novel biomarkers and therapeutic targets. Glucose metabolism and CXCR4 chemokine expression are differentially deregulated during HCC development in an oncogene-specific manner. Our [18F]FDG results correlated with glucose transporter GLUT1 gene expression and with our metabolomics data. Increased expression of CXCR4 and CD68 inflammatory markers mirrored [68Ga]pentixafor results in LT2/MYC mice. FET-based measurement of amino acid turnover are insensitive to stages of HCC-development, in our studies. Concurrently, no significant changes in expression of tyrosine metabolism genes were observed.

PRINCIPAL CONCLUSIONS

Our study highlights that identified changes in targeted molecular imaging can facilitate a better understanding of underlying biological processes and may help guide novel oncogene-specific targeted anti-tumor therapies in HCC, with promising translational potential.

MicroRNA miR-20a-5p targets CYCS to inhibit apoptosis in hepatocellular carcinoma

Hepatocellular carcinoma is a primary liver cancer, characterised by diverse etiology, late diagnoses, and poor prognosis. Hepatocellular carcinoma is mostly resistant to current treatment options, therefore, identification of more effective druggable therapeutic targets is needed. We found microRNA miR-20a-5p is upregulated during mouse liver tumor progression and in human hepatocellular carcinoma patients. In this study, we elucidated the therapeutic potential of targeting oncogenic miR-20a-5p, in vivo, in a xenograft model and in two transgenic hepatocellular carcinoma mouse models via adeno-associated virus-mediated miR-20a-Tough-Decoy treatment. In vivo knockdown of miR-20a-5p attenuates tumor burden and prolongs survival in the two independent hepatocellular carcinoma mouse models. We identified and validated cytochrome c as a novel target of miR-20a-5p. Cytochrome c plays a key role in initiation of the apoptotic cascade and in the electron transport chain. We show for the first time, that miR-20a modulation affects both these key functions of cytochrome c during HCC development. Our study thus demonstrates the promising 'two birds with one stone' approach of therapeutic in vivo targeting of an oncogenic miRNA, whereby more than one key deregulated cellular process is affected, and unequivocally leads to more effective attenuation of HCC progression and significantly longer overall survival.

Noncoding RNAs in Hepatocellular Carcinoma: Potential Applications in Combined Therapeutic Strategies and Promising Candidates of Treatment Response

The incidence of hepatocellular carcinoma (HCC) is increasing, and 40% of patients are diagnosed at advanced stages. Over the past 5 years, the number of clinically available treatments has dramatically increased for HCC, making patient management particularly complex. Immune checkpoint inhibitors (ICIs) have improved the overall survival of patients, showing a durable treatment benefit over time and a different response pattern with respect to tyrosine kinase inhibitors (TKIs). Although there is improved survival in responder cases, a sizeable group of patients are primary progressors or are ineligible for immunotherapy. Indeed, patients with nonviral etiologies, such as nonalcoholic steatohepatitis (NASH), and alterations in specific driver genes might be less responsive to immunotherapy. Therefore, improving the comprehension of mechanisms of drug resistance and identifying biomarkers that are informative of the best treatment approach are required actions to improve patient survival. Abundant evidence indicates that noncoding RNAs (ncRNAs) are pivotal players in cancer. Molecular mechanisms through which ncRNAs exert their effects in cancer progression and drug resistance have been widely investigated. Nevertheless, there are no studies summarizing the synergistic effect between ncRNA-based strategies and TKIs or ICIs in the preclinical setting. This review aims to provide up-to-date information regarding the possible use of ncRNAs as therapeutic targets in association with molecular-targeted agents and immunotherapies and as predictive tools for the selection of optimized treatment options in advanced HCCs.

The role of microRNAs in hepatocellular carcinoma: Therapeutic targeting of tumor suppressor and oncogenic genes

Hepatocellular carcinoma (HCC) is a severe malignant liver cancer with a poor prognosis and a high mortality rate. This carcinoma is a multistage process that begins with chronic hepatitis and progresses to cirrhosis, dysplastic nodules, and eventually HCC. However, the exact molecular etiology remains unclear. MicroRNAs (miRs) are small non-coding RNAs that modulate the expression of numerous genes. These molecules have become significant participants in several functions, including cell proliferation, differentiation, development, and tumorrelated properties. They have a pivotal role in carcinogenesis as oncogenes or tumor suppressor genes. Furthermore, some investigations have shown that particular miRs might be used as predictive or diagnostic markers and therapeutic targets in HCC therapy. This review study summarizes the current level of knowledge on the role of miRs in the initiation and progression of HCC.

microRNA-382 as a tumor suppressor? Roles in tumorigenesis and clinical significance

MicroRNAs (miRNAs) are small single-stranded RNAs belonging to a class of non-coding RNAs with an average length of 18-22 nucleotides. Although not able to encode any protein, miRNAs are vastly studied and found to play role in various human physiologic as well as pathological conditions. A huge number of miRNAs have been identified in human cells whose expression is straightly regulated with crucial biological functions, while this number is constantly increasing. miRNAs are particularly studied in cancers, where they either can act with oncogenic function (oncomiRs) or tumor-suppressors role (referred as tumor-suppressor/oncorepressor miRNAs). miR-382 is a well-studied miRNA, which is revealed to play regulatory roles in physiological processes like osteogenic differentiation, hematopoietic stem cell differentiation and normal hematopoiesis, and liver progenitor cell differentiation. Notably, miR-382 deregulation is reported in pathologic conditions, such as renal fibrosis, muscular dystrophies, Rett syndrome, epidural fibrosis, atrial fibrillation, amelogenesis imperfecta, oxidative stress, human immunodeficiency virus (HIV) replication, and various types of cancers. The majority of oncogenesis studies have claimed miR-382 downregulation in cancers and suppressor impact on malignant phenotype of cancer cells in vitro and in vivo, while a few studies suggest opposite findings. Given the putative role of this miRNA in regulation of oncogenesis, assessment of miR-382 expression is suggested in a several clinical investigations as a prognostic/diagnostic biomarker for cancer patients. In this review, we have an overview to recent studies evaluated the role of miR-382 in oncogenesis as well as its clinical potential.

MiR-494 induces metabolic changes through G6pc targeting and modulates sorafenib response in hepatocellular carcinoma

BACKGROUND

Metabolic reprogramming is a well-known marker of cancer, and it represents an early event during hepatocellular carcinoma (HCC) development. The recent approval of several molecular targeted agents has revolutionized the management of advanced HCC patients. Nevertheless, the lack of circulating biomarkers still affects patient stratification to tailored treatments. In this context, there is an urgent need for biomarkers to aid treatment choice and for novel and more effective therapeutic combinations to avoid the development of drug-resistant phenotypes. This study aims to prove the involvement of miR-494 in metabolic reprogramming of HCC, to identify novel miRNA-based therapeutic combinations and to evaluate miR-494 potential as a circulating biomarker.

METHODS

Bioinformatics analysis identified miR-494 metabolic targets. QPCR analysis of glucose 6-phosphatase catalytic subunit (G6pc) was performed in HCC patients and preclinical models. Functional analysis and metabolic assays assessed G6pc targeting and miR-494 involvement in metabolic changes, mitochondrial dysfunction, and ROS production in HCC cells. Live-imaging analysis evaluated the effects of miR-494/G6pc axis in cell growth of HCC cells under stressful conditions. Circulating miR-494 levels were assayed in sorafenib-treated HCC patients and DEN-HCC rats.

RESULTS

MiR-494 induced the metabolic shift of HCC cells toward a glycolytic phenotype through G6pc targeting and HIF-1A pathway activation. MiR-494/G6pc axis played an active role in metabolic plasticity of cancer cells, leading to glycogen and lipid droplets accumulation that favored cell survival under harsh environmental conditions. High miR-494 serum levels associated with sorafenib resistance in preclinical models and in a preliminary cohort of HCC patients. An enhanced anticancer effect was observed for treatment combinations between antagomiR-494 and sorafenib or 2-deoxy-glucose in HCC cells.

CONCLUSIONS

MiR-494/G6pc axis is critical for the metabolic rewiring of cancer cells and associates with poor prognosis. MiR-494 deserves attention as a candidate biomarker of likelihood of response to sorafenib to be tested in future validation studies. MiR-494 represents a promising therapeutic target for combination strategies with sorafenib or metabolic interference molecules for the treatment of HCC patients who are ineligible for immunotherapy.

Downregulation of microRNA‑494 inhibits cell proliferation in lung squamous cell carcinoma via the induction of PUMA‑α‑mediated apoptosis

Increased evidence has shown that abnormal microRNA (miRNA) plays pivotal roles in numerous types of cancer. However, their expression, function and mechanism in lung squamous cell carcinoma (LSCC) remains to be fully elucidated. The aim of the present study was to investigate the suppressive role of miR-494 in LSCC progression and elucidate its regulatory mechanism. By analyzing expression profiles of miRNAs in LSCC tissues using miRNA microarray, it was revealed that miR-494 was significantly upregulated in 22 pairs of LSCC tissues. Subsequently, reverse transcription-quantitative PCR was performed to determine the expression of miR-494 and p53-upregulated-modulator-of-apoptosis-α (PUMA-α). Western blot analysis was conducted to examine protein levels. Dual-luciferase reporter assay was used to confirm the binding between miR-494 and PUMA-α. Annexin V-fluoresceine isothiocyanate/propidium iodide staining and CCK-8 assays were employed to determine cell apoptosis and cell viability, respectively. It was also revealed that miR-494 was highly expressed in LSCC cell lines compared with that in 16HBE cells. Further experiments confirmed that knockdown of miR-494 reduced cell viability and induced LSCC apoptosis. Bioinformatics analysis predicted that miR-494 could potentially target PUMA-α; also known as Bcl-2-binding component 3, a pro-apoptotic factor, and an inverse correlation between the expression of miR-494 and PUMA-α mRNA levels in LSCC tissues was found. Furthermore, PUMA-α inhibition could reverse the promoting effect of miR-494 knockdown on apoptosis in LSCC cells. Taken together, these findings demonstrated that miR-494 functions as an oncogene by targeting PUMA-α in LSCC, and miR-494 may serve as a novel therapeutic target for treating LSCC.

MCC Gene Silencing Is a CpG Island Methylator Phenotype-Associated Factor That Predisposes Colon Cancer Cells to Irinotecan and Olaparib

Simple Summary

DNA hypermethylation of specific regulatory regions causes gene silencing that is an important cancer-promoting mechanism. A subset of colorectal cancers display concordant hypermethylation and silencing of multiple genes, and this appears to change the way in which tumors respond to some cancer therapies. The aim of this study was to evaluate how the presence of the MCC gene silencing relates to the highly methylated subset of colorectal cancers and how it may affect therapy responsiveness. We found that strong MCC silencing is found throughout the hypermethylated subset, but MCC expression is also lost or reduced in some other tumors which show hypomethylated regions of the gene. In cell culture experiments, the deletion of MCC increased the responsiveness of cancer cells to the chemotherapy drug irinotecan (SN38), and this was further augmented by a targeted cancer drug, the PARP-inhibitor Olaparib.

Abstract

Chemotherapy is a mainstay of colorectal cancer treatment, and often involves a combination drug regime. CpG island methylator phenotype (CIMP)-positive tumors are potentially more responsive to the topoisomerase-inhibitor irinotecan. The mechanistic basis of the increased sensitivity of CIMP cancers to irinotecan is poorly understood. Mutated in Colorectal Cancer (MCC) is emerging as a multifunctional tumor suppressor gene in colorectal and liver cancers, and has been implicated in drug responsiveness. Here, we found that CIMP tumors undergo MCC loss almost exclusively via promoter hypermethylation rather than copy number variation or mutations. A subset of cancers display hypomethylation which is also associated with low MCC expression, particularly in rectal cancer, where CIMP is rare. MCC knockdown or deletion was found to sensitize cells to SN38 (the active metabolite of irinotecan) or the PARP-inhibitor Olaparib. A synergistic effect on cell death was evident when these drugs were used concurrently. The improved SN38/irinotecan efficacy was accompanied by the down-regulation of DNA repair genes. Thus, differential methylation of MCC is potentially a valuable biomarker to identify colorectal cancers suitable for irinotecan therapy, possibly in combination with PARP inhibitors.

Hepatocellular Carcinoma: The Role of MicroRNAs

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related deaths worldwide. HCC is diagnosed in its advanced stage when limited treatment options are available. Substantial morphologic, genetic and epigenetic heterogeneity has been reported in HCC, which poses a challenge for the development of a targeted therapy. In this review, we discuss the role and involvement of several microRNAs (miRs) in the heterogeneity and metastasis of hepatocellular carcinoma with a special emphasis on their possible role as a diagnostic and prognostic tool in the risk prediction, early detection, and treatment of hepatocellular carcinoma.

Hepatocellular Carcinoma Is a Natural Target for Adeno-Associated Virus (AAV) 2 Vectors

Simple Summary

Gene therapy is a novel approach to treat diseases by introducing corrective genetic information into target cells. Adeno-associated virus vectors are the most frequently applied gene delivery tools for in vivo gene therapy and are also studied as part of innovative anticancer strategies. Here, we report on the natural preference of AAV2 vectors for hepatocellular carcinoma (HCC) compared to nonmalignant liver cells in mice and human tissue. This preference in transduction is due to the improved intracellular processing of AAV2 vectors in HCC, resulting in significantly more vector genomes serving as templates for transcription in the cell nucleus. Based on this natural tropism for HCC, novel therapeutic strategies can be designed or existing therapeutic approaches can be strengthened as they currently result in only a minor improvement of the poor prognosis for most liver cancer patients.

Abstract

Although therapeutic options are gradually improving, the overall prognosis for patients with hepatocellular carcinoma (HCC) is still poor. Gene therapy-based strategies are developed to complement the therapeutic armamentarium, both in early and late-stage disease. For efficient delivery of transgenes with antitumor activity, vectors demonstrating preferred tumor tropism are required. Here, we report on the natural tropism of adeno-associated virus (AAV) serotype 2 vectors for HCC. When applied intravenously in transgenic HCC mouse models, similar amounts of vectors were detected in the liver and liver tumor tissue. In contrast, transduction efficiency, as indicated by the level of transgene product, was moderate in the liver but was elevated up to 19-fold in mouse tumor tissue. Preferred transduction of HCC compared to hepatocytes was confirmed in precision-cut liver slices from human patient samples. Our mechanistic studies revealed that this preference is due to the improved intracellular processing of AAV2 vectors in HCC, resulting, for example, in nearly 4-fold more AAV vector episomes that serve as templates for gene transcription. Given this background, AAV2 vectors ought to be considered to strengthen current—or develop novel—strategies for treating HCC.

Hepatic Cancer Stem Cells: Molecular Mechanisms, Therapeutic Implications, and Circulating Biomarkers

Hepatocellular carcinoma (HCC) is one of the deadliest cancers. HCC is associated with multiple risk factors and is characterized by a marked tumor heterogeneity that makes its molecular classification difficult to apply in the clinics. The lack of circulating biomarkers for the diagnosis, prognosis, and prediction of response to treatments further undermines the possibility of developing personalized therapies. Accumulating evidence affirms the involvement of cancer stem cells (CSCs) in tumor heterogeneity, recurrence, and drug resistance. Owing to the contribution of CSCs to treatment failure, there is an urgent need to develop novel therapeutic strategies targeting, not only the tumor bulk, but also the CSC subpopulation. Clarification of the molecular mechanisms influencing CSC properties, and the identification of their functional roles in tumor progression, may facilitate the discovery of novel CSC-based therapeutic targets to be used alone, or in combination with current anticancer agents, for the treatment of HCC. Here, we review the driving forces behind the regulation of liver CSCs and their therapeutic implications. Additionally, we provide data on their possible exploitation as prognostic and predictive biomarkers in patients with HCC.

MiR-486-3p was downregulated at microRNA profiling of adrenals of multiple endocrine neoplasia type 1 mice, and inhibited human adrenocortical carcinoma cell lines

Adrenocortical carcinoma is a rare aggressive disease commonly recurring regardless of radical surgery. Although data on genomic alterations in malignant tumors are accumulating, knowledge of molecular events of importance for initiation of adrenocortical transformation is scarce. In an attempt to recognize early molecular alterations, we used adrenals from young multiple endocrine neoplasia type 1 conventional knock-out mice (Men1^+/−) closely mimicking the human MEN1 trait (i.e. transformation of pituitary, parathyroid, endocrine pancreatic, and adrenocortical cells). MicroRNA array and hierarchical clustering showed a distinct pattern. Twenty miRNAs were significantly upregulated and eleven were downregulated in Men1^+/− compared to wild type littermates. The latter included the known suppressor miRNA miR-486-3p, which was chosen for transfection in human adrenocortical carcinoma cell lines H295R and SW13. Cell growth decreased in miR-486-3p overexpressing clones and levels of the predicted target gene fatty acid synthase (FASN) and its downstream product, palmitic acid, were lowered. In conclusion, heterozygous inactivation of Men1 in adrenals results in distinct miRNA profile regulating expression of genes with impact on tumorigenesis, e.g. transcription, nucleic acid and lipid metabolism. Low levels of miR-486-3p in the early stages of transformation may contribute to proliferation by increasing FASN and thus fatty acid production. FASN as a potentially druggable target for treatment of the devastating disease adrenocortical carcinoma warrants further studies.

Elucidating the Molecular Basis of Sorafenib Resistance in HCC: Current Findings and Future Directions

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related mortality worldwide. Sorafenib is the first multi-tyrosine kinase inhibitor approved for HCC and it has represented the standard of care for advanced HCC for almost 10 years, offering a survival benefit when compared to placebo. However, this benefit is limited, showing rare objective responses and a disease control rate approaching 50–60%, with most patients experiencing disease progression at 6 months. These scant results dictate the urgent need for strategies to overcome both primary and acquired resistance. Herein we report several mechanisms supporting resistance to sorafenib in HCC patients, including activation of oncogenic pathways. Among these, the AKT/mTOR pathway plays a crucial role being at the crossroad of multiple driving events. Autophagy, multidrug-resistant phenotype, hypoxia-related mechanisms and endoplasmic reticulum stress are gaining more and more relevance as crucial events driving the response to anticancer drugs, including sorafenib. Several HCC-specific miRNAs take part to the regulation of these cellular processes. Remarkably, molecularly targeted strategies able to overcome resistance in these settings have also been reported. So far, the vast majority of data has been derived from laboratory studies, which means the need for an extensive validation. Indeed, most of the possible drug associations displaying promising effects in improving sorafenib efficacy herein described derive from preclinical explorations. Notably, data obtained in animal models can be inconsistent with regard to the human disease for efficacy, safety, side effects, best formulation and pharmacokinetics. However, they represent the necessary preliminary step to improve the management of advanced HCC.

Essential Role of the 14q32 Encoded miRNAs in Endocrine Tumors

BACKGROUND

The 14q32 cluster is among the largest polycistronic miRNA clusters. miRNAs encoded here have been implicated in tumorigenesis of multiple organs including endocrine glands.

METHODS

Critical review of miRNA studies performed in endocrine tumors have been performed. The potential relevance of 14q32 miRNAs through investigating their targets, and integrating the knowledge provided by literature data and bioinformatics predictions have been indicated.

RESULTS

Pituitary adenoma, papillary thyroid cancer and a particular subset of pheochromocytoma and adrenocortical cancer are characterized by the downregulation of miRNAs encoded by the 14q32 cluster. Pancreas neuroendocrine tumors, most of the adrenocortical cancer and medullary thyroid cancer are particularly distinct, as 14q32 miRNAs were overexpressed. In pheochromocytoma and growth-hormone producing pituitary adenoma, however, both increased and decreased expression of 14q32 miRNAs cluster members were observed. In the background of this phenomenon methodological, technical and biological factors are hypothesized and discussed. The functions of 14q32 miRNAs were also revealed by bioinformatics and literature data mining.

CONCLUSIONS

14q32 miRNAs have a significant role in the tumorigenesis of endocrine organs. Regarding their stable expression in the circulation of healthy individuals, further investigation of 14q32 miRNAs could provide a potential for use as biomarkers (diagnostic or prognostic) in endocrine neoplasms.

Global miRNA/proteomic analyses identify miRNAs at 14q32 and 3p21, which contribute to features of chronic iron-exposed fallopian tube epithelial cells

Malignant transformation of fallopian tube secretory epithelial cells (FTSECs) is a key contributing event to the development of high-grade serous ovarian carcinoma (HGSOC). Our recent findings implicate oncogenic transformative events in chronic iron-exposed FTSECs, including increased expression of oncogenic mediators, increased telomerase transcripts, and increased growth/migratory potential. Herein, we extend these studies by implementing an integrated transcriptomic and mass spectrometry-based proteomics approach to identify global miRNA and protein alterations, for which we also investigate a subset of these targets to iron-induced functional alterations. Proteomic analysis identified > 4500 proteins, of which 243 targets were differentially expressed. Sixty-five differentially expressed miRNAs were identified, of which 35 were associated with the “top” proteomic molecules (> fourfold change) identified by Ingenuity Pathway Analysis. Twenty of these 35 miRNAs are at the 14q32 locus (encoding a cluster of 54 miRNAs) with potential to be regulated by DNA methylation and histone deacetylation. At 14q32, miR-432-5p and miR-127-3p were ~ 100-fold downregulated whereas miR-138-5p was 16-fold downregulated at 3p21 in chronic iron-exposed FTSECs. Combinatorial treatment with methyltransferase and deacetylation inhibitors reversed expression of these miRNAs, suggesting chronic iron exposure alters miRNA expression via epigenetic alterations. In addition, PAX8, an important target in HGSOC and a potential miRNA target (from IPA) was epigenetically deregulated in iron-exposed FTSECs. However, both PAX8 and ALDH1A2 (another IPA-predicted target) were experimentally identified to be independently regulated by these miRNAs although TERT RNA was partially regulated by miR-138-5p. Interestingly, overexpression of miR-432-5p diminished cell numbers induced by long-term iron exposure in FTSECs. Collectively, our global profiling approaches uncovered patterns of miRNA and proteomic alterations that may be regulated by genome-wide epigenetic alterations and contribute to functional alterations induced by chronic iron exposure in FTSECs. This study may provide a platform to identify future biomarkers for early ovarian cancer detection and new targets for therapy.

MicroRNAs in the Pathogenesis of Hepatocellular Carcinoma: A Review

Simple Summary

Hepatocellular carcinoma (HCC) is one of the most frequently occurring cancers, and the prognosis for late-stage HCC remains poor. A better understanding of the pathogenesis of HCC is expected to improve outcomes. MicroRNAs (miRNAs) are small, noncoding, single-stranded RNAs that regulate the expression of various target genes, including those in cancer-associated genomic regions or fragile sites in various human cancers. We summarize the central roles of miRNAs in the pathogenesis of HCC and discuss their potential utility as valuable biomarkers and new therapeutic agents for HCC.

Abstract

Hepatocellular carcinoma (HCC) is the seventh most frequent cancer and the fourth leading cause of cancer mortality worldwide. Despite substantial advances in therapeutic strategies, the prognosis of late-stage HCC remains dismal because of the high recurrence rate. A better understanding of the etiology of HCC is therefore necessary to improve outcomes. MicroRNAs (miRNAs) are small, endogenous, noncoding, single-stranded RNAs that modulate the expression of their target genes at the posttranscriptional and translational levels. Aberrant expression of miRNAs has frequently been detected in cancer-associated genomic regions or fragile sites in various human cancers and has been observed in both HCC cells and tissues. The precise patterns of aberrant miRNA expression differ depending on disease etiology, including various causes of hepatocarcinogenesis, such as viral hepatitis, alcoholic liver disease, or nonalcoholic steatohepatitis. However, little is known about the underlying mechanisms and the association of miRNAs with the pathogenesis of HCC of various etiologies. In the present review, we summarize the key mechanisms of miRNAs in the pathogenesis of HCC and emphasize their potential utility as valuable diagnostic and prognostic biomarkers, as well as innovative therapeutic targets, in HCC diagnosis and treatment.

MicroRNA-342-3p is a potent tumour suppressor in hepatocellular carcinoma

BACKGROUND & AIMS

Hepatocellular carcinoma (HCC) is a cancer with multiple aetiologies and widespread prevalence. Largely refractory to current treatments, HCC is the fourth leading cause of cancer-related deaths worldwide. MicroRNAs (miRNAs) are important regulators in HCCs. We aimed to identify tumour suppressor miRNAs during tumour regression in a conditional c-MYC-driven mouse model (LT2/MYC) of HCC, and to evaluate their therapeutic potential for HCC treatment.

METHODS

We performed miRNA expression profiling of developed and regressing LT2/MYC tumours and in-depth in vitro gain- and loss-of-function analyses. The effect of adeno-associated virus (AAV) vector-mediated miR-342-3p treatment was evaluated in 3 HCC mouse models.

RESULTS

We identified miR-342-3p as a tumour suppressor miRNA in HCC, with increased expression in regressing tumours. Forced miR-342-3p expression in hepatoma cells showed significantly decreased cell proliferation, migration, and colony formation. In vivo administration of AAV-miR-342-3p led to significant attenuation of tumour development and increased overall survival. We identified monocarboxylic acid transporter 1 (MCT1) as a bona fide target of miR-342-3p in HCC. We show that the tumour suppressor role of miR-342-3p is executed partly by modulating the lactate transport function of MCT1. Importantly, we find miR-342-3p downregulated in tumours from patients with HCC compared with matched non-tumour tissues, inversely correlating with MCT1 expression. We observed similar findings in TCGA-LIHC data.

CONCLUSIONS

In our study, we identified and validated miR-342-3p as a tumour suppressor miRNA in HCC. We demonstrated its therapeutic efficacy in significantly attenuating tumour development, and prolonging survival, in different HCC mouse models. Identification of miR-342-3p as an effective tumour suppressor opens a therapeutic avenue for miRNA-mediated attenuation of HCC development.

LAY SUMMARY

Hepatocellular carcinoma (HCC), the most common type of liver cancer, affects diverse populations and has a global impact, being the fourth leading cause of cancer deaths worldwide. There are currently no systemic therapies for HCC that can significantly prolong long-term survival. Thus, novel effective treatment options are urgently required. To understand the molecular basis of tumour regression, we compared tumours and regressing liver tumours in mice. We show that a small non-coding miRNA, miR-342-3p, is a tumour suppressor in HCC. Expression of miR-342-3p is low in tumours and high in regressing tumours. When miR-342-3p is delivered to mouse livers with HCC, it can significantly slow down liver tumour development and improve survival. Our study highlights the promising therapeutic potential of miR-342-3p intervention in HCC.

MicroRNA-27a-3p directly targets FosB to regulate cell proliferation, apoptosis, and inflammation responses in immunoglobulin a nephropathy

Immunoglobulin A nephropathy (IgAN) constitutes the most common primary glomerulonephritis worldwide; however, the exact pathogenesis of IgAN is unknown. Previous genome-wide analysis of microRNA (miRNA) expression in the kidney has confirmed that miRNAs are closely related to the pathological changes of IgAN. Accordingly, in this study we found that miR-27a-3p is upregulated in IgAN kidney tissues in addition to human podocytes and tubule epithelial HK2 but not mesangial cells. Methylthiazolyldiphenyl-tetrazolium bromide (MTT), flow cytometry, real-time polymerase chain reaction, western blot, and enzyme-linked immunosorbent assays were used to verify the regulatory effects of miR-27a-3p and its inhibition on cell proliferation, apoptosis, and release of inflammatory factors in podocytes and HK2 cells. The target genes of miR-27a-3p were predicted using bioinformatics software; the identity of FosB as a target gene of miR-27a-3p was confirmed by luciferase report assay and western blot. Overall, our findings demonstrated that miR-27a-3p regulates cell apoptosis, cell proliferation, and the release of inflammatory cytokines of human podocytes and HK2 cells by directly targeting FosB. Our results therefore suggested that miR-27a-3p might be associated with the pathophysiology of IgAN and may represent a potential target for further studies related to IgAN mechanism or therapeutics.

Long Non-coding RNA LINC01420 Contributes to Pancreatic Cancer Progression Through Targeting KRAS Proto-oncogene

BACKGROUND

Long non-coding RNAs (lncRNAs) have been increasingly uncovered to participate in multiple human cancers, including pancreatic cancer (PC). However, the underlying mechanisms of most of the lncRNAs have not been fully understood yet.

AIMS

In this study, we probed the role and latent mechanism of LINC01420 in PC.

METHODS

Several online tools were applied. Gene expression was evaluated by qRT-PCR or Western blot. Both in vitro and in vivo assays were conducted to probe LINC01420 function in PC. ChIP, RIP, and luciferase reporter assays were performed to determine relationships between genes.

RESULTS

The bioinformatics analyses revealed LINC01420 was highly expressed in PC tissues. Besides, LINC01420 was pronouncedly upregulated in PC cell lines and its depletion controlled PC cell proliferation and EMT in vitro and hindered tumor growth in vivo. Importantly, KRAS was proved to mediate LINC01420-facilitated PC cell proliferation. Further, we explained that KRAS transcription was regulated by MYC, while LINC01420 enhanced the binding of MYC to KRAS promoter in the nucleus of PC cells. Intriguingly, LINC01420 boosted MYC expression in the cytoplasm of PC cells by sponging miR-494-3p.

CONCLUSION

This study illustrated that LINC01420 accelerates PC progression through releasing miR-494-3p-silenced MYC in cytoplasm and upregulating MYC-activated KRAS in nucleus, unveiling LINC01420 as a latent therapeutic strategy for PC patients.

MicroRNAs Targeting MYC Expression: Trace of Hope for Pancreatic Cancer Therapy. A Systematic Review

Background

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest malignancies and a major health problem worldwide. There were no major advances in conventional treatments in inhibiting tumor progression and increasing patient survival time. In order to suppress mechanisms responsible for tumor cell development such as those with oncogenic roles, more advanced therapeutic strategies should be sought. One of the most important oncogenes of pancreatic cancer is the MYC gene. The overexpression of MYC can activate many tumorigenic processes such as cell proliferation and pancreatic cancer cell invasion. MiRNAs are important molecules that are confirmed by targeting mRNA transcripts to regulate the expression of the MYC gene. Therefore, restoring MYC-repressing miRNAs expression tends to be an effective method of treating MYC-driven cancers.

Objective

The purpose of this study was to identify all validated microRNAs targeting C-MYC expression to inhibit PDAC progression by conducting a systematic review.

Methods

In this systematic review study, the papers published between 2000 and 2020 in major online scientific databases including PubMed, Scopus, and Web of Science were screened, following inclusion and exclusion criteria. We extracted all the experimental studies that showed miRNAs could target the expression of the MYC gene in PDAC.

Results

Eight papers were selected from a total of 89 papers. We found that six miRNAs (Let-7a, miR-145, miR-34a, miR-375, miR-494, and miR-148a) among the selected studies were validated for targeting MYC gene and three of them confirmed Let-7a as a direct MYC expression regulator in PC cells. Finally, we summarized the latest shreds of evidence of experimentally validated miRNAs targeting the MYC gene with respect to PDAC’s therapeutic potential.

Conclusion

Restoring the expression of MYC-repressing miRNAs tends to be an effective way to treat MYC-driven cancers such as PDAC. Several miRNAs have been proposed to target this oncogene via bioinformatics tools, but only a few have been experimentally validated for pancreatic cancer cells and models. Further studies should be conducted to find the interaction network of miRNA-MYC to develop more successful therapeutic strategies for PC, using the synergistic effects of these miRNAs.

Possible Molecular Mechanisms for the Roles of MicroRNA-21 Played in Lung Cancer

Background:

We aimed to find the possible molecular mechanisms for the roles of microRNA-21 underlying lung cancer development.

Methods:

MicroRNA-21-5p inhibitor was transfected into A549 cells. Total RNA was isolated from 10 samples, including 3 in control group (A549 cells), 3 in negative control group (A549 cells transferred with microRNA-21 negative control), and 4 in SH group (A549 cells transferred with microRNA-21 inhibitor), followed by RNA sequencing. Then, differentially expressed genes were screened for negative control group versus control group, SH group versus control group, and SH group versus negative control group. Functional enrichment analyses, protein–protein interaction network, and modules analyses were conducted. Target genes of hsa-miR-21-5p and transcription factors were predicted, followed by the regulatory network construction.

Results:

Minichromosome maintenance 10 replication initiation factor and cell division cycle associated 8 were important nodes in protein–protein interaction network with higher degrees. Cell division cycle associated 8 was enriched in cell division biological process. Furthermore, maintenance 10 replication initiation factor and cell division cycle associated 8 were significantly enriched in cluster 1 and micro-RNA-transcription factor-target genes regulating network. In addition, transcription factor Dp family member 3 (transcription factor of maintenance 10 replication initiation factor and cell division cycle associated 8) and RAD21 cohesin complex component (transcription factor of maintenance 10 replication initiation factor) were target genes of hsa-miR-21-5p.

Conclusions:

Micro-RNA-21 may play a key role in lung cancer partly via maintenance 10 replication initiation factor and cell division cycle associated 8. Furthermore, microRNA-21 targeted cell division cycle associated 8 and then played roles in lung cancer via the process of cell division. Transcription factor Dp family member 3 and RAD21 cohesin complex component are important transcription factors in microRNA-21-interfered lung cancer.

MicroRNAs as Theranostics Targets in Oral Carcinoma Stem Cells

Oral cancer belongs to head and neck squamous cell carcinoma and has been recognized as one of the most prevalent malignancies worldwide. Recent studies have suggested that cancer stem cells (CSCs) may participate in tumor initiation, metastasis and even recurrence, so the regulation of CSCs has drawn significant attention over the past decade. Among various molecules that are associated with CSCs, non-coding RNAs (ncRNAs) have been indicated as key players in the acquisition and maintenance of cancer stemness. In addition, accumulating studies have shown that the aberrant expression of these ncRNAs may serve as surrogate diagnostic markers or even therapeutic targets for cancer treatment. The current study reviews the previous work by us and others to summarize how these ncRNAs affect oral cancer stemness and their potential theranostic applications. A better understanding of the implication of these ncRNAs in oral tumorigenesis will facilitate the translation of basic ncRNA research into clinical application in the future.

The Extracellular RNA Communication Consortium: Establishing Foundational Knowledge and Technologies for Extracellular RNA Research

The Extracellular RNA Communication Consortium (ERCC) was launched to accelerate progress in the new field of extracellular RNA (exRNA) biology and to establish whether exRNAs and their carriers, including extracellular vesicles (EVs), can mediate intercellular communication and be utilized for clinical applications. Phase 1 of the ERCC focused on exRNA/EV biogenesis and function, discovery of exRNA biomarkers, development of exRNA/EV-based therapeutics, and construction of a robust set of reference exRNA profiles for a variety of biofluids. Here, we present progress by ERCC investigators in these areas, and we discuss collaborative projects directed at development of robust methods for EV/exRNA isolation and analysis and tools for sharing and computational analysis of exRNA profiling data.

Differential expression of angiogenesis-related miRNAs and VEGFA in cirrhosis and hepatocellular carcinoma

INTRODUCTION

Liver cirrhosis (LC) is a heterogeneous liver disease, the last stage of liver fibrosis, and the major risk factor for hepatocellular carcinoma (HCC). Our study aimed to evaluate the expression of microRNAs and the endothelial vascular growth factor (VEGFA) gene in LC and HCC.

MATERIAL AND METHODS

The sample group consisted of 46 tissue samples: 21 of LC, 15 of HCC, and 10 of non-tumoural and non-cirrhotic liver tissue (control group). MiRNAs were chosen based on a mirDIP prediction database as regulators of the VEGFA gene. Gene expression of VEGF and miRNAs was quantified by real-time quantitative polymerase chain reaction. VEGFA protein expression was evaluated by ELISA.

RESULTS

VEGFA gene expression was significantly overexpressed in LC compared to the control group (p < 0.0001). Hsa-miR-206 (p = 0.0313) and hsa-miR-637 (p = 0.0156) were down-expressed in LC. In HCC, hsa-miR-15b (p = 0.0010), hsa-miR-125b (p = 0.0010), hsa-miR-423-3p (p = 0.0010), hsa-miR-424 (p = 0.0313), hsa-miR-494 (p < 0.0001), hsa-miR-497 (p < 0.0001), hsa-miR-612 (p = 0.0078), hsa-miR-637 (p < 0.0001), and hsa-miR-1255b (p = 0.0156) presented down-expression.

CONCLUSIONS

Overexpression of VEGFA in LC suggests impairment of angiogenesis in this tissue. The differential expression of microRNAs in LC and HCC observed in our study can lead to the evaluation of possible biomarkers for these diseases.

Role of MicroRNA in the Diagnosis and Management of Hepatocellular Carcinoma

INTRODUCTION

Hepatocellular Carcinoma (HCC) is one of the most common malignant tumors in the world and comes third in cancer-induced mortality. The need for improved and more specific diagnostic methods that can detect early-stage disease is immense, as it is amenable to curative modalities, while advanced HCC is associated with low survival rates. microRNA (miRNA) expression is deregulated in HCC and this can be implemented both diagnostically and therapeutically.

OBJECTIVE

To provide a concise review on the role of miRNA in diagnosis, prognosis, and treatment of HCC.

METHODS

We conducted a comprehensive review of the PubMed bibliographic database.

RESULTS

Multiple miRNAs are involved in the pathogenesis of HCC. Measurement of the levels of these miRNAs either in tumor tissue or in the blood constitutes a promising diagnostic, as well as prognostic tool. OncomiRs are miRNAs that promote tumorigenesis, thus inhibiting them by administering antagomiRs is a promising treatment option. Moreover, replacement of the depleted miRNAs is another potential therapeutic approach for HCC. Modification of miRNA levels may also regulate sensitivity to chemotherapeutic agents.

CONCLUSION

miRNA play a pivotal role in HCC pathogenesis and once the underlying mechanisms are elucidated, they will become part of everyday clinical practice against HCC.

MicroRNAs in Animal Models of HCC

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related mortality. Molecular heterogeneity and absence of biomarkers for patient allocation to the best therapeutic option contribute to poor prognosis of advanced stages. Aberrant microRNA (miRNA) expression is associated with HCC development and progression and influences drug resistance. Therefore, miRNAs have been assayed as putative biomarkers and therapeutic targets. miRNA-based therapeutic approaches demonstrated safety profiles and antitumor efficacy in HCC animal models; nevertheless, caution should be used when transferring preclinical findings to the clinics, due to possible molecular inconsistency between animal models and the heterogeneous pattern of the human disease. In this context, models with defined genetic and molecular backgrounds might help to identify novel therapeutic options for specific HCC subgroups. In this review, we describe rodent models of HCC, emphasizing their representativeness with the human pathology and their usefulness as preclinical tools for assessing miRNA-based therapeutic strategies.

MicroRNA-802 induces hepatitis B virus replication and replication through regulating SMARCE1 expression in hepatocellular carcinoma

Growing evidences have indicated that microRNAs (miRNAs) can regulate hepatitis B virus (HBV) expression and replication, playing crucial roles in the development of HBV infection. Until now, the functional role and mechanism of miR-802 in HBV replication and expression remain unknown. We indicated that miR-802 expression was upregulated in the HBV-associated hepatocellular carcinoma (HCC) tissues compared with the adjacent noncancerous samples. In addition, we showed that the SMARCE1 expression level was downregulated in the HBV-associated HCC tissues compared with the adjacent noncancerous samples. miR-802 expression was negatively related with MARCE1 expression in HBV-associated HCC tissues. Moreover, miR-802 expression was upregulated, and SMARCE1 expression was downregulated in the HBV-infected HepG2.2.15 cells. Ectopic expression of miR-802 significantly enhanced HBV DNA replication, while knockdown of miR-802 significantly decreased HBV DNA replication. We showed that overexpression of miR-802 promoted HbsAg and HbeAg expression, while inhibition of miR-802 decreased HbsAg and HbeAg expression. Furthermore, we indicated that ectopic expression of SMARCE1 suppressed HBV DNA replication and decreased the expression level of HbsAg and HbeAg. Finally, we showed that overexpression of miR-802 promoted HBV DNA replication through regulating SMARCE1 expression. These results suggested the important roles of miR-802 on HBV expression and replication, which may shed new light on the development of treatment for HBV.

Overexpression of lncRNA PIK3CD-AS1 promotes expression of LATS1 by competitive binding with microRNA-566 to inhibit the growth, invasion and metastasis of hepatocellular carcinoma cells

Background

This study is conducted to investigate the effect of lncRNA PIK3CD-AS1 on the growth and metastasis of hepatocellular carcinoma (HCC) and its potential mechanism.

Methods

Hepatocellular carcinoma tissues and adjacent normal tissues together with HCC cells and normal liver cells were obtained for detecting expression of PIK3CD-AS1, microRNA-566 (miR-566) and LATS1. Additionally, a series of experiments were performed to determine cell proliferation, migration, invasion, cell cycle distribution and apoptosis of HCC cells. The xenograft tumor model of HCC was established and the growth rate and weight of xenograft tumor in nude mice were compared. Furthermore, the binding site between PIK3CD-AS1 and miR-566 as well as between miR-566 and LATS1 were verified.

Results

LncRNA PIK3CD-AS1 was downregulated in HCC tissues and cells, and mainly located in cytoplasm. Overexpression of PIK3CD-AS1 inhibited proliferation, colony formation, invasion, migration, epithelial–mesenchymal transition (EMT) and cell cycle progression and promoted apoptosis of HCC cells. Overexpression of PIK3CD-AS1 decreased the growth rate and weight of xenograft tumor in nude mice PIK3CD-AS1 competitively combined with miR-566 to regulate expression of LAST1.

Conclusion

Collectively, our study suggests that the expression of PIK3CD-AS1 was down-regulated in HCC, and overexpression of PIK3CD-AS1 promoted the expression of LATS1 by competitive binding of miR-566 to inhibit the growth, invasion and metastasis of HCC cells.

Mir-494 inhibits osteoblast differentiation by regulating BMP signaling in simulated microgravity

Although the BMPR-SMAD-RUNX2 signaling pathway plays widely recognized roles in BMP-induced osteogenesis, factors regulating this pathway remain to be defined. In this study, we used simulated microgravity models, which represent mechanical unloading conditions, to detect miRNAs that function in osteoblast differentiation. We found that miR-494 was persistently increased in C2C12 cells subjected to clinorotation conditions and in osteoblasts isolated from tail-suspended rats. Experiments showed that the overexpression of miR-494 correlated with a marked reduction in osteoblast differentiation genes and a decrease in osteogenesis in BMP2-induced osteogenetic differentiation. In contrast, the inhibition of miR-494 promoted BMP2-induced osteogenesis and partially rescued osteoblast differentiation disorder under simulated microgravity conditions. Mechanism studies revealed that miR-494 directly targeted BMPR2 and RUNX2, both of which play vital roles in the BMPR-SMAD-RUNX2 signaling pathway. More importantly, we demonstrated a positive feedback loop between miR-494 and MYOD, a critical transcription factor for myogenesis, indicating that miR-494 may participate in deciding cell fate of the multipotent mesenchymal stem cells (MSCs). Collectively, our study reveals an important role for miR-494 in regulating osteogenesis, the identification of which not only clarifies a regulator of BMP2-induced osteoblast differentiation, but also offers a possible strategy for preventing bone loss under microgravity conditions.

Mouse Model of Mutated in Colorectal Cancer Gene Deletion Reveals Novel Pathways in Inflammation and Cancer

BACKGROUND & AIMS

The early events by which inflammation promotes cancer are still not fully defined. The MCC gene is silenced by promoter methylation in colitis-associated and sporadic colon tumors, but its functional significance in precancerous lesions or polyps is not known. Here, we aimed to determine the impact of Mcc deletion on the cellular pathways and carcinogenesis associated with inflammation in the mouse proximal colon.

METHODS

We generated knockout mice with deletion of Mcc in the colonic/intestinal epithelial cells (Mcc^ΔIEC) or in the whole body (Mcc^Δ/Δ). Drug-induced lesions were analyzed by transcriptome profiling (at 10 weeks) and histopathology (at 20 weeks). Cell-cycle phases and DNA damage proteins were analyzed by flow cytometry and Western blot of hydrogen peroxide-treated mouse embryo fibroblasts.

RESULTS

Transcriptome profiling of the lesions showed a strong response to colon barrier destruction, such as up-regulation of key inflammation and cancer-associated genes as well as 28 interferon γ-induced guanosine triphosphatase genes, including the homologs of Crohn's disease susceptibility gene IRGM. These features were shared by both Mcc-expressing and Mcc-deficient mice and many of the altered gene expression pathways were similar to the mesenchymal colorectal cancer subtype known as consensus molecular subtype 4 (CMS4). However, Mcc deletion was required for increased carcinogenesis in the lesions, with adenocarcinoma in 59% of Mcc^ΔIEC compared with 19% of Mcc-expressing mice (P = .002). This was not accompanied by hyperactivation of β-catenin, but Mcc deletion caused down-regulation of DNA repair genes and a disruption of DNA damage signaling.

CONCLUSIONS

Loss of Mcc may promote cancer through a failure to repair inflammation-induced DNA damage. We provide a comprehensive transcriptome data set of early colorectal lesions and evidence for the in vivo significance of MCC silencing in colorectal cancer.

MiR-494 acts as a tumor promoter by targeting CASP2 in non-small cell lung cancer

MiR-494 plays an important role in several types of human cancers, including non-small cell lung cancer (NSCLC). Although the role of miR-494 has been investigated in several studies, the expression profile and underlying mechanism are still poorly understood. In this study, we found that overexpression of miR-494 promoted the proliferation and colony formation of NSCLC cells and reduced their sensitivity to cisplatin-induced apoptosis. By using microarray and Dual luciferase reporter assays, we further showed that caspase-2 (CASP2) is a functional target of miR-494, and the expression of CASP2 is inversely associated with miR-494 in vitro. In addition, miR-494 promoted the proliferation and colony formation of NSCLC cells and reduced their sensitivity to cisplatin-induced apoptosis by targeting CASP2. Therefore, our results suggest that miR-494 plays an oncomiR role in NSCLC cells and may be a candidate biomarker for malignant transformation and a therapeutic target of NSCLC.

MiR-29a and miR-652 Attenuate Liver Fibrosis by Inhibiting the Differentiation of CD4+ T Cells

BACKGROUND

Liver fibrosis is the response of liver diseases that puzzles patients. MiRNAs were involved in the regulating processes of liver fibrosis. This study aims to investigate the effects of ARRB1 mediated by miR-29a and miR-652 on liver fibrosis and its possible mechanism.

METHODS

Liver fibrosis of mice was induced by intraperitoneal injection of CCl₄. Liver function was observed by the levels of alanine transaminase (ALT) and aspartate transaminase (AST). Flow cytometry was used to detect the percent of T helper17 (Th17). ELISA (Enzyme linked immunoassay) was used to detect the levels of Interleukin-17 (IL-17) and Interleukin-22 (IL-22). Real-time PCR was used to detect the expression of IL-17A, IL-22, miR-29a, miR-652 and β-Arrestin 1 Gene (ARRB1). Western blot was used to detect the protein expression of ARRB1.

RESULTS

CCl₄ supplementation significantly increased the level of ALT and AST, the percent of Th17, the level of IL-17A, IL-22, miR-29a and miR-652, but decreased ARRB1. Overexpression of miR-29a/miR-652 prominently decreased Th17, IL-17A, IL-22 and ARRB1 in the normal CD4+ T cells. Both miR-29a and miR-652 targeted ARRB1 to regulate its expression. The effects of miR-29a/miR-652 overexpression on CD4+ T cells were reversed by ARRB1 overexpression. In vivo experiments demonstrated the protective role of miR-29a/miR-652 overexpression on liver fibrosis.

CONCLUSION

ARRB1 mediated by miR-29a and miR-652 probably involved in the CD4+ T cells differentiation in patients with liver fibrosis, and functioned as a biomarker of fibrosis liver.Key words: liver fibrosis, miR-29a, miR-652, ARRB1, CD4+ T cells.

Small but Heavy Role: MicroRNAs in Hepatocellular Carcinoma Progression

Hepatocellular carcinoma (HCC), which accounts for 85-90% of primary liver cancer, is the fifth most common malignant tumor and the third leading cause of cancer-related deaths worldwide, but the pathological mechanism of HCC is still not fully elucidated. miRNAs are evolutionarily endogenous small noncoding RNAs that negatively regulate gene expression via posttranscriptional inhibition or target mRNA degradation in several diseases, especially human cancer. Therefore, discovering the roles of miRNAs is appealing to scientific researchers. Emerging evidence has shown that the aberrant expressions of numerous miRNAs are involved in many HCC biological processes. In hepatocarcinogenesis, miRNAs with dysregulated expression can exert their function as oncogenes or tumor suppressors depending on their cellular target during the cell cycle, and in tumor development, differentiation, apoptosis, angiogenesis, metastasis, and progression of the tumor microenvironment. In this review, we summarize current findings on miRNAs and assess their functions to explore the molecular mechanisms of tumor progression in HCC.

Gene-gene interaction network analysis of hepatocellular carcinoma using bioinformatic software

Information processing tools and bioinformatics software have markedly advanced the ability of researchers to process and analyze biological data. Data from the genomes of humans and model organisms aid researchers to identify topics to study, which in turn improves predictive accuracy, facilitates the identification of relevant genes and simplifies the validation of laboratory data. The objective of the present study was to investigate the regulatory network constituted by long non-coding RNAs (lncRNAs), microRNAs (miRNAs) and mRNA in hepatocellular carcinoma (HCC). Microarray data from HCC datasets were downloaded from The Cancer Genome Atlas database, and the Limma package in R was used to identify the differentially expressed genes (DEGs) between HCC and normal samples. Gene ontology enrichment analysis of DEGs was conducted using the Database for Annotation, Visualization, and Integrated Discovery. TargetScan, microcosm, miRanda, miRDB and PicTar were used to predict target genes. lncRNAs associated with HCC were probed using the lncRNASNP database, and a lncRNA-miRNA-mRNA regulatory network was visualized using Cytoscape. The present study identified 114 differentially expressed miRNAs and 2,239 differentially expressed mRNAs; of these, 725 were downregulated genes that were primarily involved in complement and coagulation cascades, fatty acid metabolism and butanoate metabolism, among others. The remaining 1,514 were upregulated genes principally involved in DNA replication, oocyte meiosis and homologous recombination, among others. Through the integrated analysis of associations between different types of RNAs and target gene prediction, the present study identified 203 miRNA-mRNA pairs, including 28 miRNAs and 170 mRNAs, and identified 348 lncRNA-miRNA pairs, containing 28 miRNAs. Therefore, owing to the association between lncRNAs-miRNAs-mRNAs, the present study screened out 2,721 regulatory associations. The data in the present study provide a comprehensive bioinformatic analysis of genes, functions and pathways that may be involved in the pathogenesis of HCC.

MiR-320 promotes B cell proliferation and the production of aberrant glycosylated IgA1 in IgA nephropathy

IgA nephropathy (IgAN) is one of the most common primary glomerulonephritis. However, the etiology of this disease is complex and the pathogenesis of IgAN is still unknown. MicroRNAs (miRNAs) play important roles in a lot of pathological and physiological processes. In this study, we showed that the expression of miR-320 was significantly upregulated in renal tissues and urinary of IgAN patients. Moreover, the intra-renal expression level of miR-320 had significant correlation with miR-320 expression in the urinary of IgAN patients. Overexpression of miR-320 increased B cell proliferation and promoted cyclin D1 expression. Furthermore, we identified that PTEN was direct target gene of miR-320 in the B cell. Ectopic expression of miR-320 suppressed PTEN expression. Overexpression of miR-320 decreased Cosmc expression in the B cell. In addition, we demonstrated that Cosmc expression was significantly downregulated in the renal tissues and urinary of IgAN patients. The intra-renal expression level of Cosmc had significant correlation with Cosmc expression of urinary in IgAN patients. We proved that the expression level of Cosmc was negatively correlated with the expression of miR-320 in the renal tissues of IgAN patients. Overexpression of miR-320 promoted the B cell proliferation through suppressing PTEN expression. Taken together, these data suggested that miR-320 acted an important role in the development of IgAN.

Down-regulation of 14q32-encoded miRNAs and tumor suppressor role for miR-654-3p in papillary thyroid cancer

Papillary thyroid carcinoma (PTC) is the most prevalent malignant neoplasia of the thyroid gland. A fraction of PTC cases show loss of differentiation and aggressive behavior, with radioiodine therapy resistance and metastasis. Although microRNAs (miRNAs) emerged as promising molecular markers for PTC, their role in the loss of differentiation observed during PTC progression remains to be fully understood. We performed the large-scale analysis of miRNA expression during PTC progression in BRAFT1799A-transgenic animals (Tg-Braf) and thyroid cancer cell lines and identified the marked downregulation of several miRNAs from the region 14q32. Data from The Cancer Genome Atlas (TCGA) confirmed the global downregulation of miRNAs from the 14q32 region in human PTC. The regulatory network potentially suppressed by these miRNAs suggests that key cancer-related biological processes such as cell proliferation, adhesion, migration and angiogenesis. Among the downregulated miRNAs, we observed that miR-654-3p levels decrease with long-term PTC progression in Tg-Braf mice and inversely correlate with EMT. The in vitro restoration of miR-654-3p decreased cell proliferation and migration and induced reprogramming of metastasis-related genes, suggesting a tumor suppressor role for this miRNA. In conclusion, we show global downregulation of 14q32-encoded miRNAs in an in vivo model of PTC progression. The potential circuitry in which these miRNAs are involved suggests that these miRNAs could play a key role in the pathophysiology of PTC and therefore be relevant for the development of new therapeutic strategies.

Proliferation-associated miRNAs-494, -205, -21 and -126 detected by in situ hybridization: expression and prognostic potential in breast carcinoma patients

PURPOSE

To visualize by in situ hybridization (ISH) the levels of a set of proliferation-associated miRNAs and to evaluate their impact and clinical applicability in prognostication of invasive breast carcinoma.

METHODS

Tissue specimen from breast carcinoma patients were investigated for miRNAs-494, -205, -21 and -126. Prognostic associations for levels of miRNAs were analyzed based on complete clinical data and up to 22.5-year follow-up of the patient material (n = 285). For detection of the miRNAs, an automated sensitive protocol applying in situ hybridization was developed.

RESULTS

MiRNA-494 indicated prognostic value for patients with invasive breast carcinoma. Among node-negative disease reduced level of miRNA-494 predicted 8.5-fold risk of breast cancer death (p = 0.04). Altered levels and expression patterns of the studied miRNAs were observed in breast carcinomas as compared to benign breast tissue.

CONCLUSIONS

The present paper reports for the first time on the prognostic value of miRNA-494 in invasive breast cancer. Particularly, detection of miRNA-494 could benefit patients with node-negative breast cancer in identifying subgroups with aggressive disease. Based on our experience, the developed automatic ISH method to visualize altered levels of miRNAs-494, -205, -21 and -126 could be applied to routine pathology diagnostics providing that conditions of tissue treatment, especially fixation delays, are managed.

The epigenetically regulated miR-494 associates with stem-cell phenotype and induces sorafenib resistance in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) represents the second cause of cancer-related mortality worldwide and is associated with poor prognosis, especially in patients not amenable for curative treatments. The multi-kinase inhibitor sorafenib represents the first-line treatment option for advanced HCC; nevertheless, its effectiveness is limited due to tumor heterogeneity as well as innate or acquired drug resistance, raising the need for new therapeutic strategies. MicroRNAs (miRNAs) involvement in treatment response as well as their safety and efficacy in preclinical models and clinical trials have been widely documented in the oncologic field, including HCC. Here, we identified miR-494 upregulation in a subgroup of human and rat HCCs with stem cell-like characteristics, as well as multiple epigenetic mechanisms involved in its aberrant expression in HCC cell lines and patients. Moreover, we identified p27, puma and pten among miR-494 targets, contributing to speed up cell cycle progression, enhance survival potential in stressful conditions and increase invasive and clonogenic capabilities. MiR-494 overexpression increased sorafenib resistance via mTOR pathway activation in HCC cell lines and, in line, high miR-494 levels associated with decreased sorafenib response in two HCC animal models. A sorafenib-combined anti-miR-494-based strategy revealed an enhanced anti-tumor potential with respect to sorafenib-only treatment in our HCC rat model. In conclusion, our findings suggested miR-494 as a possible therapeutic target as well as a candidate biomarker for patient stratification in advanced HCC.

MicroRNA-494 promotes cancer progression and targets adenomatous polyposis coli in colorectal cancer

Background

Aberrant activation of the Wnt/β-catenin signaling pathway is frequently observed in colorectal cancer (CRC). β-catenin is the major Wnt signaling pathway effector and inactivation of adenomatous polyposis coli (APC) results in nuclear accumulation of β-catenin. It has been suggested that inactivation of APC plays an important role in activation of the Wnt/β-catenin pathway and in the progression of colorectal tumorigenesis. However, the mechanism through which APC mediates colorectal tumorigenesis is not understood. Increasing evidence suggests that the dysregulation of microRNAs (miRNAs) is involved in colorectal tumorigenesis. Although miR-494 has been reported as being an upregulated miRNA, the interplay between miR-494 and APC-mediated colorectal tumorigenesis progression remains unclear.

Methods

The expression of miR-494 in tissues from patients diagnosed with CRC was analyzed using a microarray and real-time PCR. The effects of miR-494 on cell proliferation and tumorigenesis in CRC cells were analyzed by flow cytometry, colony formation assays, BrdU incorporation assays, and CCK8 assays. The correlation between miR-494 expression and APC expression, as well as the mechanisms by which miR-494 regulates APC in CRC were also addressed.

Results

miR-494 was significantly upregulated in CRC tissues, and this increase was negatively associated with APC expression. APC was confirmed to be a direct target of miR-494 in CRC. Furthermore, overexpression of miR-494 induced Wnt/β-catenin signaling by targeting APC, thus promoting CRC cell growth.

Conclusions

This study provides novel insights into the role of miR-494 in controlling CRC cell proliferation and tumorigenesis, and identifies miR-494 as a potential prognostic marker and therapeutic target.

miR-494 protects pancreatic β-cell function by targeting PTEN in gestational diabetes mellitus

Gestational diabetes mellitus (GDM) is one of the most common pregnancy complications characterized by insulin resistance and pancreatic β-cell dysfunction. Increasing evidence suggests that microRNAs (miRNAs) play key roles in the diverse types of diabetes, including GDM. However, the underlying mechanisms remain largely unknown. The purpose of this study is to investigate the role of microRNAs in GDM. The microarray data of dysregulated miRNAs in blood and placenta was retrieved in the GEO dataset under the accession number GSE19649. Quantitative reverse transcription PCR (qRT-PCR) was performed to analyze the expression levels of miR-494 in peripheral blood from twenty pairs of gestational diabetes (GDM) women and healthy women. Then, we investigated the effects of miR-494 on the insulin secretion of pancreatic β-cells. Moreover, the role of this miR-494 in regulating the proliferation and apoptosis of pancreatic β-cells were determined by MTT assay and flow cytometry, respectively in INS1 cells transfected with a miR-494 mimic or inhibitor. In addition, the direct target of miR-494 was confirmed using 3' untranslated region (UTR) luciferase reporter assay. Our data demonstrated that the miR-494 level was significantly decreased in the blood of GDM patients, and the low level was associated with a high concentration of blood glucose. Furthermore, overexpression of miR-494 improved pancreatic β-cell dysfunction by enhancing insulin secretion and total insulin content, inducing cell proliferation, and inhibiting cell apoptosis, whereas miR-494 knockdown exhibited decreased insulin secretion and proliferation, as well as stimulated apoptosis. In addition, phosphatase and tensin homolog (PTEN) which has been shown to play a pivotal role in apoptosis, was proved to be a direct target of miR-494 in pancreatic β-cells. More importantly, siRNA-induced downregulation of PTEN reversed the effects of miR-494 knockdown on insulin secretion, cell proliferation, and apoptosis of pancreatic β-cells.

'MCC' protein interacts with E-cadherin and β-catenin strengthening cell-cell adhesion of HCT116 colon cancer cells

E-cadherin and β-catenin are key proteins that are essential in the formation of the epithelial cell layer in the colon but their regulatory pathways that are disrupted in cancer metastasis are not completely understood. Mutated in colorectal cancer (MCC) is a tumour suppressor gene that is silenced by promoter methylation in colorectal cancer and particularly in patients with increased lymph node metastasis. Here, we show that MCC methylation is found in 45% of colon and 24% of rectal cancers and is associated with proximal colon, poorly differentiated, circumferential and mucinous tumours as well as increasing T stage and larger tumour size. Knockdown of MCC in HCT116 colon cancer cells caused a reduction in E-cadherin protein level, which is a hallmark of epithelial-mesenchymal transition in cancer, and consequently diminished the E-cadherin/β-catenin complex. MCC knockdown disrupted cell-cell adhesive strength and integrity in the dispase and transepithelial electrical resistance assays, enhanced hepatocyte growth factor-induced cell scatter and increased tumour cell invasiveness in an organotypic assay. The Src/Abl inhibitor dasatinib, a candidate anti-invasive drug, abrogated the invasive properties induced by MCC deficiency. Mechanistically, we establish that MCC interacts with the E-cadherin/β-catenin complex. These data provide a significant advance in the current understanding of cell-cell adhesion in colon cancer cells.

miR‑494 inhibits cell proliferation and metastasis via targeting of CDK6 in osteosarcoma

Tumorigenesis is a multistep process involving various cell growth-associated factors. Accumulated evidence indicates that the disordered regulation of microRNAs (miRNAs) contributes to tumorigenesis. However, the detailed mechanism underlying the involvement of miRNAs in oncogenesis remains to be fully elucidated. In the present study, the repressed expression of microRNA (miR)-494 was identified in 18 patients with osteosarcoma (OS) and OS cell lines, compared with corresponding controls. To determine whether deregulated miR-494 exerts tumor-suppressive effects in the development of OS, the effects of miR-494 on cell proliferation and metastasis were evaluated. It was found that the restoration of miR-494 in MG-63 and U2OS cells led to inhibited cell proliferation and attenuated migratory propensity in vitro, determined through analysis using MTT, colony formation and Transwell assays. In addition, overexpression of miR-494 markedly suppressed the tumor volume and weight in vivo. In accordance, the ectopic expression of miR-494 induced cell cycle arrest at the G1/S phase in OS cells. Bioinformatics analysis and luciferase reporter assays were performed to investigate the potential regulatory role of miR-494, the results of which indicated that miR-494 directly targeted cyclin-dependent kinase 6 (CDK6). Of note, the data obtained through reverse transcription-quantitative polymerase chain reaction and western blot analyses suggested that the elevated expression of miR-494 resulted in reduced mRNA and protein expression levels of CDK6. Taken together, these findings indicated that the miR-494/CDK6 axis has a significant tumor-suppressive effect on OS, and maybe a diagnostic and therapeutic target for the treatment of OS.

Expression of miR-711 and mechanism of proliferation and apoptosis in human gastric carcinoma

MicroRNAs (miRs) are involved in many aspects of cell biology, including cell proliferation and apoptosis, two critical aspects of tumor biology. We investigated the effect of miR-711 on Bcl-2 expression in human MGC803 gastric cancer cells and the mechanism of cell proliferation, apoptosis, and invasion. Expression of miR-711 and Bcl-2 was significantly increased in gastric adenocarcinoma compared to adjacent normal tissue. Inhibition of miR-711 in MGC803 gastric cancer cells decreased the expression of Bcl-2, decreased cell proliferation, decreased the invasion ability, and increased apoptosis. The expression of Bcl-2 protein correlated with clinical staging, lymph node metastasis, and tumor differentiation in patients with gastric cancer. The expression of miR-711 positively correlated with the expression of Bcl-2, suggesting that miR-711 and Bcl-2 are co-regulated and involved in the development of gastric cancer.

MicroRNA‑494 inhibits nerve growth factor‑induced cell proliferation by targeting cyclin D1 in human corneal epithelial cells

Nerve growth factor (NGF) is expressed in the human corneal epithelium and stroma. It is an efficient therapy for human corneal ulcers caused by neurotropic disease. However, little is known about the molecular mechanism of NGF in healing human corneal epithelial diseases. Numerous microRNAs (miRNAs) are expressed in the cornea and miRNAs have important roles in regulating corneal development. In the present study, novel miRNA regulators were demonstrated to be involved in NGF‑induced human corneal epithelial cell (hCEC) proliferation. NGF treatment significantly downregulated the expression of miRNA‑494 in hCECs in vitro. Furthermore, miRNA‑494 increased G1 arrest in the immortalized human corneal epithelial cell (ihCEC) line and suppressed cell proliferation. Accordingly, bioinformatics programs and luciferase reporter assay demonstrated that miRNA‑494 directly targeted cyclin D1 by binding to a sequence in the 3'‑untranslated region. In addition, overexpression of miRNA‑494 decreased both basal and NGF‑induced cyclin D1 expression. NGF treatment partially suppressed miRNA‑494 expression and restored cyclin D1 expression. Furthermore, co‑transfection of miRNA‑494 with the cyclin D1 ORF clone partially restored cyclin D1 mRNA and protein expression. These findings indicate that miRNA‑494 and its target cyclin D1 may be a crucial axis for NGF in regulating the proliferation of hCEC. Specific modulation of miRNA‑494 in hCEC could represent an attractive approach for treating cornea epithelial diseases.

Hinokitiol up-regulates miR-494-3p to suppress BMI1 expression and inhibits self-renewal of breast cancer stem/progenitor cells

Hinokitiol (β-thujaplicin) is a tropolone-related compound that has anti-microbe, anti-inflammation, and anti-tumor effects. Cancer stem/progenitor cells (CSCs) are a subpopulation of cancer cells with tumor initiation, chemoresistant, and metastatic properties and have been considered the important therapeutic target in future cancer therapy. Previous studies reported that hinokitiol exhibits an anti-cancer activity against murine tumor cells through the induction of autophagy. The current research revealed that hinokitiol suppressed the self-renewal capabilities of human breast CSCs (BCSCs) and inhibited the expression of BMI1 at protein level without suppressing its mRNA. Treatment of hinokitiol in mammospheres induced the expression of miR-494-3p and inhibition of miR-494-3p expression in BCSCs. This treatment abolished the suppressive effects of hinokitiol in mammosphere formation and BMI1 expression. BMI1 is a target of miR-494-3p by luciferase-based 3′UTR reporter assay. Overexpression of miR-494-3p in BCSCs caused the down-regulation of BMI1 protein, inhibition of mammosphere forming capability, and suppression of their tumorigenicity. Moreover, miR-494-3p expression was significantly and inversely correlated with patient survival in two independent public database sets. Furthermore, treatment of hinokitiol in vivo suppressed the growth of xenograft human breast tumors as well as the expression of BMI1 and ALDH1A1 in xenograft tumors. In conclusion, these data suggest that hinokitiol targets BCSCs through the miR-494-3p-mediated down-modulation of BMI1 expression.

Effects of miR-21 on proliferation and apoptosis in human gastric adenocarcinoma cells

The present study investigated the expression of miR-21 in MGC803 gastric cancer cells and its effects on Bcl-2 expression and cell proliferation, apoptosis, and invasion. In total 50 patients were recruited with gastric cancer who were admitted to the Henan Province People's Hospital. The samples of gastric cancer and the adjacent normal tissues were collected after surgery. We found that mRNA levels of miR-21 and Bcl-2 were significantly elevated in tumor tissues compared to control tissue. The expression of Bcl-2 protein was also elevated in cancerous tissue. This high expression of Bcl-2 was associated with clinical stage, lymph node metastasis, and tumor differentiation degree. Inhibition of miR-21 reduced the levels of miR-21 and Bcl-2 in MGC803 cells, and lowered cell proliferation and invasiveness. These results indicate that miR-21 and Bcl-2 may participate in the occurrence and development of gastric adenocarcinoma, suggesting their potential role as biomarkers and therapeutic targets.

In vivo Reprogramming of Cancer Metabolism by MYC

The past few decades have welcomed tremendous advancements toward understanding the functional significance of altered metabolism during tumorigenesis. However, many conclusions drawn from studies of cancer cells in a dish (i.e., in vitro) have been put into question as multiple lines of evidence have demonstrated that the metabolism of cells can differ significantly from that of primary tumors (in vivo). This realization, along with the need to identify tissue-specific vulnerabilities of driver oncogenes, has led to an increased focus on oncogene-dependent metabolic programming in vivo. The oncogene c-MYC (MYC) is overexpressed in a wide variety of human cancers, and while its ability to alter cellular metabolism is well-established, translating the metabolic requirements, and vulnerabilities of MYC-driven cancers to the clinic has been hindered by disparate findings from in vitro and in vivo models. This review will provide an overview of the in vivo strategies, mechanisms, and conclusions generated thus far by studying MYC's regulation of metabolism in various cancer models.

Therapeutic Inhibition of miR-4260 Suppresses Colorectal Cancer via Targeting MCC and SMAD4

Dysregulation of microRNAs (miRNAs, miRs) and their putative target genes have been increasingly reported to contribute to colorectal cancer. However, miRNAs that directly target the mutated in colorectal cancer (MCC) gene, a tumor suppressor which is downregulated or inactivated in colorectal cancer, remain largely unknown. By using an array-based miRNA analysis, we identified a group of miRNAs that were dysregulated in human metastatic versus non-metastatic colorectal cancer tissues. One of these miRNAs, miR-4260, was predicted to target MCC in the miRDB database. Results using human HCT116 and HT29 colorectal cancer cell lines showed that miR-4260 mimic enhanced cell proliferation and migration and reduced apoptosis induced by the chemotherapeutic agent 5-fluorouracil while miR-4260 inhibitor had inverse effects. Furthermore, miR-4260 negatively regulated MCC as well as SMAD4 by directly binding to the 3'untranslational region (3'UTR). Using siRNAs targeting MCC or SMAD4, we showed that upregulation of MCC and SMAD4 was essential to mediate the functional roles of miR-4260 inhibitor in colorectal cancer cells. Our in vivo experiments indicated that inhibition of miR-4260 reduced colorectal tumor growth in nude mice subcutaneously implanted with HCT116 cells. Significantly, miR-4260 was increased in human colorectal cancer tissues with simultaneous downregulation of MCC and SMAD4, strongly suggesting the clinical relevance of targeting miR-4260 in the treatment of colorectal cancer. In summary, we identified miR-4260 as a novel oncomiR for colorectal cancer that targets MCC and SMAD4. Inhibition of miR-4260 can, therefore, be a potential therapeutic strategy for colorectal cancer.