DNA methylation-regulated miR-193a-3p dictates resistance of hepatocellular carcinoma to 5-fluorouracil via repression of SRSF2 expression

Targeting microRNA methylation: Innovative approaches to diagnosing and treating hepatocellular carcinoma

Hepatocellular carcinoma (HCC) stands as the most prevalent form of primary liver cancer and is frequently linked to underlying chronic liver conditions such as hepatitis B, hepatitis C, and cirrhosis. Despite the progress achieved in the field of oncology, HCC remains a significant clinical challenge, primarily due to its typically late-stage diagnosis and the complex and multifaceted nature of its tumor biology. These factors contribute to the limited effectiveness of current treatment modalities and result in poor patient prognosis. Emerging research has underscored the vital role of microRNAs (miRNAs)-small, non-coding RNA molecules that play a pivotal part in the post-transcriptional regulation of gene expression. These miRNAs are integral to a wide array of cellular functions, including proliferation, apoptosis, and differentiation, and their dysregulation is closely associated with the pathogenesis of various cancers, notably HCC. A major focus in recent studies has been on the epigenetic regulation of miRNAs through methylation, a key mechanism that modulates gene expression. This process, involving the addition of methyl groups to CpG islands in the promoter regions of miRNA genes, can result in either gene silencing or activation, influencing the expression of oncogenes and tumor suppressor genes. Such alterations have profound implications for tumor growth, metastasis, and resistance to treatment. Evidence suggests that aberrant miRNA methylation can serve as a powerful biomarker for early detection and prognosis in HCC and may present novel opportunities for therapeutic intervention. This review aims to provide a comprehensive overview of the current landscape of miRNA methylation in HCC, elucidating its significance in the molecular mechanisms of liver cancer and examining its potential for clinical application. By exploring the diagnostic and therapeutic potential of miRNA methylation, we seek to highlight its value in enhancing personalized treatment strategies and improving patient outcomes.

Role of miRNA in pathogenesis, diagnosis, and prognosis in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common cancers and is responsible for the second cancer-related death globally. Many treatment regimens have been developed to cure the disease; however, life expectancy is still low. Therefore, there is an urgent need to explore new selective, specific, and robust diagnosis markers for efficient early recognition of the ailment. Along with the diagnosis, the treatment's effectiveness can be determined by prognostic markers, and miRNAs are excellent tools for the diagnosis and prognosis of HCC. In addition, the altered expression profile of a few miRNAs promotes HCC cell migration and invasion, and selective up- or downregulation of these responsible genes may help mitigate the disorder. On one hand, few of the miRNAs have been found to enhance angiogenesis, a crucial step of tumor growth; on the other hand, upregulation of specific miRNAs is reported to suppress angiogenesis and resulting tumor growth of HCC cells. Exosomal miRNAs have significant implications in promoting angiogenesis, increased endothelial cell permeability, tube formation, and metastasis to hepatic and pulmonary tissues. miRNA also attributes to drug resistance toward chemotherapy and the prevention of autophagy also. Identifying novel miRNA and determining their differential expression in HCC tissue may serve as a potential tool for diagnosis, prognosis, and therapy to enhance the life expectancy and quality of life of HCC patients. In the present review, we have summarized the recent advances in HCC-related research.

Alternative splicing: a bridge connecting NAFLD and HCC

Non-alcoholic fatty liver disease (NAFLD) is becoming the most important risk factor for hepatocellular carcinoma (HCC). Understanding the progression of benign diseases to HCC is crucial for early prevention and reversal of malignant transformation. Alternative splicing (AS) of RNA plays a role in the pathogenicity, initiation, and transformation of liver disease. We summarize the changes or mutations in the activity of splicing factors in NAFLD and HCC, as well as the impact of AS mediated by epigenetic modifications such as DNA methylation, RNA methylation, histone modification, and protein phosphorylation on liver cell fate. We also summarize therapeutic methods and drugs that are helpful for treating NAFLD, HCC, and the early stages of NAFLD progression to HCC.

Circ_0006404 enhances hepatocellular carcinoma progression by regulating miR-624

Growing studies have demonstrated that circRNAs (circular RNAs) act potential roles in tumor metastasis and progression. However, the expression and function of circ_0006404 in hepatocellular carcinoma (HCC) remain to be investigated. The expression of circ_0006404 and miR-624 was detected by qRT-PCR. CCK-8 assay, flow cytometry, and wound healing were performed to determine cell proliferation, cycle, and migration. The target of circ_0006404 was studied by bioinformatics and luciferase activity analysis. Our data indicated that circ_0006404 was overexpressed in HCC specimens and cells and ectopic expression of circ_0006404 increased HCC cell growth, cycle, and migration. Moreover, we showed that miR-624 was downregulated in HCC specimens and cells and miR-624 expression was negatively correlated with circ_0006404 expression in HCC specimens. Circ_0006404 sponged miR-624 in HCC cell, and the overexpression of circ_0006404 suppressed miR-624 expression in HCC cell. Furthermore, circ_0006404 induced HCC cell growth, cycle, and migration via regulating miR-624. These results elucidated that circ_0006404 facilitated HCC progression and might act as one new biomarker for this carcinoma.

RNA splicing: a dual-edged sword for hepatocellular carcinoma

RNA splicing is the fundamental process that brings diversity at the transcriptome and proteome levels. The spliceosome complex regulates minor and major processes of RNA splicing. Aberrant regulation is often associated with different diseases, including diabetes, stroke, hypertension, and cancer. In the majority of cancers, dysregulated alternative RNA splicing (ARS) events directly affect tumor progression, invasiveness, and often lead to poor survival of the patients. Alike the rest of the gastrointestinal malignancies, in hepatocellular carcinoma (HCC), which alone contributes to ~ 75% of the liver cancers, a large number of ARS events have been observed, including intron retention, exon skipping, presence of alternative 3'-splice site (3'SS), and alternative 5'-splice site (5'SS). These events are reported in spliceosome and non-spliceosome complexes genes. Molecules such as MCL1, Bcl-X, and BCL2 in different isoforms can behave as anti-apoptotic or pro-apoptotic, making the spliceosome complex a dual-edged sword. The anti-apoptotic isoforms of such molecules bring in resistance to chemotherapy or cornerstone drugs. However, in contrast, multiple malignant tumors, including HCC that target the pro-apoptotic favoring isoforms/variants favor apoptotic induction and make chemotherapy effective. Herein, we discuss different splicing events, aberrations, and antisense oligonucleotides (ASOs) in modulating RNA splicing in HCC tumorigenesis with a possible therapeutic outcome.

A New Functional Gene, Zinc Finger Protein 485 (ZNF485), is Involved in Bladder Cancer Proliferation

BACKGROUND

Bladder cancer is the second most common urological cancer worldwide, with low early diagnosis and high mortality. The limited progress in diagnostics and treatment greatly impedes the survival of bladder cancer patients.

OBJECTIVE

Potential therapeutic biomarkers are urgently needed for future clinical treatment.

METHODS

We analyzed the sequencing data and corresponding clinicopathological features and survival information of bladder cancer patients in the TCGA database and identified a new zinc finger protein 485 gene, termed ZNF485, which is highly expressed in the tissues of bladder cancer patients and was verified in cells, animal models and tissue microarrays.

RESULTS

We found that inhibition of ZNF485 in the bladder cancer cell lines T24 and 5637 obviously inhibited proliferation and promoted the apoptosis of cancer cells. Furthermore, wound healing and invasion assays showed that downregulation of ZNF485 significantly decreased the mobility and invasion of T24 and 5637 cells. In addition, ZNF485-shRNA transfection obviously inhibited tumor growth in nude mice. Immunohistochemical results of clinical samples showed that the expression level of ZNF485 protein in cancer tissues was higher than that in adjacent tissues. Mechanistic analysis identified possible downstream target genes.

CONCLUSIONS

Taken together, the results provide evidence that ZNF485 is involved in bladder cancer proliferation and might be a potential therapeutic biomarker for the treatment of this disease.

MicroRNA as a Potential Therapeutic Molecule in Cancer

Small noncoding RNAs, as post-translational regulators of many target genes, are not only markers of neoplastic disease initiation and progression, but also markers of response to anticancer therapy. Hundreds of miRNAs have been identified as biomarkers of drug resistance, and many have demonstrated the potential to sensitize cancer cells to therapy. Their properties of modulating the response of cells to therapy have made them a promising target for overcoming drug resistance. Several methods have been developed for the delivery of miRNAs to cancer cells, including introducing synthetic miRNA mimics, DNA plasmids containing miRNAs, and small molecules that epigenetically alter endogenous miRNA expression. The results of studies in animal models and preclinical studies for solid cancers and hematological malignancies have confirmed the effectiveness of treatment protocols using microRNA. Nevertheless, the use of miRNAs in anticancer therapy is not without limitations, including the development of a stable nanoconstruct, delivery method choices, and biodistribution. The aim of this review was to summarize the role of miRNAs in cancer treatment and to present new therapeutic concepts for these molecules. Supporting anticancer therapy with microRNA molecules has been verified in numerous clinical trials, which shows great potential in the treatment of cancer.

Mig-6 Inhibits Autophagy in HCC Cell Lines by Modulating miR-193a-3p

Mitogen-inducible gene 6 (Mig-6) is a tumor suppressor gene that plays an important role in many types of cancers by interacting with EGFR. However, its molecular mechanism in hepatocellular carcinoma (HCC) and its relationship with miRNAs need to be elucidated. Therefore, this study aimed to explore whether Mig-6 could promote apoptosis and the inhibition of autophagy via its downstream miRNA in HCC cell lines. We used two cell lines, HepG2 and HLE, to establish Mig-6 overexpression and knockdown experiments, as well as miR-193a mimic and inhibitor experiments. The miRNA microarray profiling was also used to verify Mig-6-regulated miRNA. We found that Mig-6 induced apoptosis and reduced autophagy of HCC cell lines. miR-193a-3p is a Mig-6-regulated miRNA in the Mig-6-overexpression model. It affected the apoptosis and autophagy of HCC cells, at least partly by regulating the expression of TGF-β2. Additionally, the relationship between Mig-6 and transforming growth factor TGF-β2 was explored in depth for the first time. These findings revealed an important role of Mig-6 in the apoptosis and autophagy of HCC cells by regulating miR-193a-3p, providing a novel insight into the therapeutic target in HCC.

The Role of miRNA in the Pathophysiology of Neuroendocrine Tumors

Neuroendocrine tumors (NETs) represent a tumor group that is both rare and heterogeneous. Prognosis is largely determined by the tumor grading and the site of the primary tumor and metastases. Despite intensive research efforts, only modest advances in diagnostic and therapeutic approaches have been achieved in recent years. For patients with non-respectable tumor stages, prognosis is poor. In this context, the development of novel diagnostic tools for early detection of NETs and prediction of tumor response to therapy as well as estimation of the overall prognosis would greatly improve the clinical management of NETs. However, identification of novel diagnostic molecules is hampered by an inadequate understanding of the pathophysiology of neuroendocrine malignancies. It has recently been demonstrated that microRNA (miRNA), a family of small RNA molecules with an established role in the pathophysiology of quite different cancer entities, may also play a role as a biomarker. Here, we summarize the available knowledge on the role of miRNAs in the development of NET and highlight their potential use as serum-based biomarkers in the context of this disease. We discuss important challenges currently preventing their use in clinical routine and give an outlook on future directions of miRNA research in NET.

SPNS2 Downregulation Induces EMT and Promotes Colorectal Cancer Metastasis via Activating AKT Signaling Pathway

Spinster homologue 2 (SPNS2), a transporter of S1P (sphingosine-1-phosphate), has been reported to mediate immune response, vascular development, and pathologic processes of diseases such as cancer via S1P signaling pathways. However, its biological functions and expression profile in colorectal cancer (CRC) is elusive. In this study, we disclosed that SPNS2 expression, which was regulated by copy number variation and DNA methylation of its promoter, was dramatically upregulated in colon adenoma and CRC compared to normal tissues. However, its expression was lower in CRC than in colon adenoma, and low expression of SPN2 correlated with advanced T/M/N stage and poor prognosis in CRC. Ectopic expression of SPNS2 inhibited cell proliferation, migration, epithelial–mesenchymal transition (EMT), invasion, and metastasis in CRC cell lines, while silencing SPNS2 had the opposite effects. Meanwhile, measuring the intracellular and extracellular level of S1P after overexpression of SPNS2 pinpointed a S1P-independent model of SPNS2. Mechanically, SPNS2 led to PTEN upregulation and inactivation of Akt. Moreover, AKT inhibitor (MK2206) abrogated SPNS2 knockdown-induced promoting effects on the migration and invasion, while AKT activator (SC79) reversed the repression of migration and invasion by SPNS2 overexpression in CRC cells, confirming the pivotal role of AKT for SPNS2’s function. Collectively, our study demonstrated the suppressor role of SPNS2 during CRC metastasis, providing new insights into the pathology and molecular mechanisms of CRC progression.

5-Fluorouracil: A Narrative Review on the Role of Regulatory Mechanisms in Driving Resistance to This Chemotherapeutic Agent

5-fluorouracil (5-FU) is among the mostly administrated chemotherapeutic agents for a wide variety of neoplasms. Non-coding RNAs have a central impact on the determination of the response of patients to 5-FU. These transcripts via modulation of cancer-related pathways, cell apoptosis, autophagy, epithelial-mesenchymal transition, and other aspects of cell behavior can affect cell response to 5-FU. Modulation of expression levels of microRNAs or long non-coding RNAs may be a suitable approach to sensitize tumor cells to 5-FU treatment via modulating multiple biological signaling pathways such as Hippo/YAP, Wnt/β-catenin, Hedgehog, NF-kB, and Notch cascades. Moreover, there is an increasing interest in targeting these transcripts in various kinds of cancers that are treated by 5-FU. In the present article, we provide a review of the function of non-coding transcripts in the modulation of response of neoplastic cells to 5-FU.

Splicing factor SRSF2-centric gene regulation

Serine/arginine-rich splicing factor 2 (SRSF2) is a splicing factor that is widely expressed in a variety of mammalian cell types. Increasing evidence has confirmed that SRSF2 plays vital roles in a number of biological and pathological processes. Therefore, it is important to understand how its expression is regulated, and how it regulates the expression of its target genes. Recently, we found that SRSF2 expression could be upregulated by herpes simplex virus-1 (HSV-1) infection, and that altered SRSF2 expression, in turn, epigenetically regulates the transcription of HSV-1 genes. Further studies on T cell exhaustion demonstrated that upregulated SRSF2 in exhausted T cells elevated the levels of multiple immune checkpoint molecules by associating with the acyl-transferases, P300 and CBP, and by altering histone modification near the transcription start sites of these genes, thereby influencing signal transducer and activator of transcription 3 binding to these gene promoters. These findings suggest that SRSF2 acts as an important sensor and effector during disease progression. Here, we discuss the molecules that regulate SRSF2 gene expression and their associated mechanisms, and the mechanisms via which SRSF2 regulates the expression of target genes, thus providing novel insights into the central role of SRSF2 in gene regulation.

Transcriptome-wide analysis reveals insight into tumor suppressor functions of 1B3, a novel synthetic miR-193a-3p mimic

Emerging data show that microRNA 193a-3p (miR-193a-3p) has a suppressive role in many cancers and is often downregulated in tumors, as compared to surrounding normal tissues. Therefore, mimics of miR-193a-3p could be used as an attractive therapeutic approach in oncology. To better understand and document the molecular mechanism of action of 1B3, a novel synthetic miRNA-193a-3p mimic, RNA sequencing was performed after transfection of 1B3 in six different human tumor cell lines. Genes differentially expressed (DE) in at least three cell lines were mapped by Ingenuity Pathway Analysis (IPA), and interestingly, these results strongly indicated upregulation of the tumor-suppressive phosphatase and tensin homolog (PTEN) pathway, as well as downregulation of many oncogenic growth factor signaling pathways. Importantly, although unsurprisingly, IPA identified miR-193a-3p as a strong upstream regulator of DE genes in an unbiased manner. Furthermore, biological function analysis pointed to an extensive link of 1B3 with cancer, via expected effects on tumor cell survival, proliferation, migration, and cell death. Our data strongly suggest that miR-193a-3p/1B3 is a potent tumor suppressor agent that targets various key oncogenic pathways across cancer types. Therefore, the introduction of 1B3 into tumor cells may represent a promising strategy for cancer treatment.

The DNA methylation-regulated MCTP1 activates the drug-resistance of esophageal cancer cells

Accumulating studies have demonstrated that drug-resistance remains a great obstacle for the effective treatment of cancers. Esophageal cancer is still one of the most common cancers worldwide, which also suffers from the drug-resistance during clinical treatment. Here we performed drug-resistance profiling assays and identified several drug-resistant and drug-sensitive esophageal cancer cell lines. The following methylation sequencing showed that the MCTP1 gene is hypermethylated in the drug-resistant esophageal cancer cells. As a result, the expression of MCTP1 is down-regulated in the drug-resistant esophageal cancer cells. Down-regulation of MCTP1 also affects the migration and apoptosis of esophageal cancer cells, as revealed by the wound-healing and apoptosis assays. Further investigations proposed two signaling pathways that might involve in the MCTP1-mediated drug-resistance of esophageal cancer cells. All these results suggested that MCTP1 activates the drug-resistance of esophageal cancer cells, which has implications for further design of new biomarker of esophageal cancer treatment.

Flavonoid display ability to target microRNAs in cancer pathogenesis

MicroRNAs (miRNAs) are non-coding, conserved, single-stranded nucleotide sequences involved in physiological and developmental processes. Recent evidence suggests an association between miRNAs' deregulation with initiation, promotion, progression, and drug resistance in cancer cells. Besides, miRNAs are known to regulate the epithelial-mesenchymal transition, angiogenesis, autophagy, and senescence in different cancer types. Previous reports proposed that apart from the antioxidant potential, flavonoids play an essential role in miRNAs modulation associated with changes in cancer-related proteins, tumor suppressor genes, and oncogenes. Thus, flavonoids can suppress proliferation, help in the development of drug sensitivity, suppress metastasis and angiogenesis by modulating miRNAs expression. In the present review, we summarize the role of miRNAs in cancer, drug resistance, and the chemopreventive potential of flavonoids mediated by miRNAs. The potential of flavonoids to modulate miRNAs expression in different cancer types demonstrate their selectivity and importance as regulators of carcinogenesis. Flavonoids as chemopreventive agents targeting miRNAs are extensively studied in vitro, in vivo, and pre-clinical studies, but their efficiency in targeting miRNAs in clinical studies is less investigated. The evidence presented in this review highlights the potential of flavonoids in cancer prevention/treatment by regulating miRNAs, although further investigations are required to validate and establish their clinical usefulness.

Hsa_circ_0006916 Knockdown Represses the Development of Hepatocellular Carcinoma via Modulating miR-599/SRSF2 Axis

Background

The aberrantly expressed circular RNAs (circRNAs) are implicated in the progression of hepatocellular carcinoma (HCC). CircRNA hsa_circ_0006916 (circ_0006916) is dysregulated in HCC, but the function and mechanism of this circRNA in HCC development remain uncertain.

Methods

Thirty paired HCC and normal tissues were collected. circ_0006916, microRNA (miR)-599 and serine/arginine rich splicing factor 2 (SRSF2) abundances were examined via quantitative reverse transcription polymerase chain reaction or Western blot. Cell viability, colony ability, migration, invasion, cell cycle and apoptosis were tested via cell counting kit-8, colony formation, wound healing analysis, transwell analysis, and flow cytometry. The interaction between miR-599 and circ_0006916 or SRSF2 was analyzed via dual-luciferase reporter and RNA immunoprecipitation analyses. The function of circ_0006916 on cell growth in vivo was analyzed via xenograft model.

Results

circ_0006916 expression was increased in HCC tissues and cell lines. circ_0006916 knockdown reduced cell viability, colony formation, migration and invasion and caused cell cycle arrest and apoptosis. miR-599 was targeted via circ_0006916, and miR-599 knockdown reversed the influence of circ_0006916 silence on HCC progression. SRSF2 was targeted via miR-599, and miR-599 overexpression suppressed cell viability, colony formation, migration and invasion and promoted cell cycle arrest and apoptosis via decreasing SRSF2. circ_0006916 could regulate SRSF2 expression via miR-599. circ_0006916 knockdown decreased HCC cell growth in the xenograft model.

Conclusion

circ_0006916 knockdown represses the progression of HCC via regulating miR-599 and SRSF2.

LncRNA UCA1 Affects the Cell Proliferation, Migration, Invasion and Apoptosis of Hepatic Carcinoma Cells by Targeting MicroRNA-193a-3p

OBJECTIVE/BACKGROUND

Hepatic carcinoma (HCC) is the fourth lethal cancer in the world, but its relationship with lncRNA urothelial cancer-associated 1 (UCA1)/microRNA-193a-3p axis remains unclear, so this study would explore the relationship.

METHODS

A real-time polymerase chain reaction (RT-PCR) assay was carried out to quantify lncRNA UCA1 and microRNA-193a-3p in HCC tissues and cells, and relevant overexpression or inhibition vectors were constructed to analyze the influences of lncRNA UCA1 and microRNA-193a-3p on HCC cells. A Transwell assay was used to measure invasion and migration of HCC cells, and a Western blot assay to quantify protein biomarkers of apoptosis, invasion, and migration, a MTT assay to determine cell viability, a flow cytometry to detect cell cycle, and a dual-luciferase reporter gene assay to analyze the correlation between lncRNA UCA1 and microRNA-193a-3p.

RESULTS

LncRNA UCA1 was increased in HCC, while microRNA-193a-3p was decreased. Down-regulated lncRNA UCA1 could up-regulate microRNA-193a-3p, and down-regulated lncRNA UCA1 or up-regulated microRNA-193a-3p would strengthen cell apoptosis and weaken cell migration, invasion, and proliferation. Furthermore, lncRNA UCA1 could negatively regulate microRNA-193a-3p by binding to it.

CONCLUSION

LncRNA UCA1 promotes malignant hyperproliferation of HCC cells by repressing microRNA-193a-3p.

Non-Coding RNAs: Regulating Disease Progression and Therapy Resistance in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC), the primary liver cancer arising from hepatocytes, is a universal health problem and one of the most common malignant tumors. Surgery followed by chemotherapy as well as tyrosine kinase inhibitors (TKIs), such as sorafenib, are primary treatment procedures for HCC, but recurrence of disease because of therapy resistance results in high mortality. It is necessary to identify novel regulators of HCC for developing effective targeted therapies that can significantly interfere with progression of the disease process. Non-coding RNAs (ncRNAs) are an abundant group of versatile RNA transcripts that do not translate into proteins, rather serve as potentially functional RNAs. The role of ncRNAs in regulating diverse aspects of the carcinogenesis process are gradually being elucidated. Recent advances in RNA sequencing technology have identified a plethora of ncRNAs regulating all aspects of hepatocarcinogenesis process and serving as potential prognostic or diagnostic biomarkers. The present review provides a comprehensive description of the biological roles of ncRNAs in disease process and therapy resistance, and potential clinical application of these ncRNAs in HCC.

Restoration of miR-193a expression is tumor-suppressive in MYC amplified Group 3 medulloblastoma

Medulloblastoma, a highly malignant pediatric brain tumor, consists of four molecular subgroups, namely WNT, SHH, Group 3, and Group 4. The expression of miR-193a, a WNT subgroup-specific microRNA, was found to be induced by MYC, an oncogenic target of the canonical WNT signaling. MiR-193a is not expressed in Group 3 medulloblastomas, despite MYC expression, as a result of promoter hypermethylation. Restoration of miR-193a expression in the MYC amplified Group 3 medulloblastoma cells resulted in inhibition of growth, tumorigenicity, and an increase in radiation sensitivity. MAX, STMN1, and DCAF7 were identified as novel targets of miR-193a. MiR-193a mediated downregulation of MAX could suppress MYC activity since it is an obligate hetero-dimerization partner of MYC. MYC induced expression of miR-193a, therefore, seems to act as a feedback inhibitor of MYC signaling. The expression of miR-193a resulted in widespread repression of gene expression that included not only several cell cycle regulators, WNT, NOTCH signaling genes, and those encoding DNA replication machinery, but also several chromatin modifiers like SWI/SNF family genes and histone-encoding genes. MiR-193a expression brought about a reduction in the global levels of H3K4me3, H3K27ac, the histone marks of active chromatin, and an increase in the levels of H3K27me3, a repressive chromatin mark. In cancer cells having high MYC expression, MYC brings about transcriptional amplification of all active genes apart from the induction of its target genes. MiR-193a, on the other hand, brought about global repression of gene expression. Therefore, miR-193a has therapeutic potential in the treatment of not only Group 3 medulloblastomas but possibly other MYC overexpressing aggressive cancers as well.

Alternative Splicing in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) accounts for the majority of primary liver cancer cases, with more than 850,000 new diagnoses per year globally. Recent trends in the United States have shown that liver cancer mortality has continued to increase in both men and women, while 5-year survival remains below 20%. Understanding key mechanisms that drive chronic liver disease progression to HCC can reveal new therapeutic targets and biomarkers for early detection of HCC. In that regard, many studies have underscored the importance of alternative splicing as a source of novel HCC prognostic markers and disease targets. Alternative splicing of pre-mRNA provides functional diversity to the genome, and endows cells with the ability to rapidly remodel the proteome. Genes that control fundamental processes, such as metabolism, cell proliferation, and apoptosis, are altered globally in HCC by alternative splicing. This review highlights the major splicing factors, RNA binding proteins, transcriptional targets, and signaling pathways that are of key relevance to HCC. We highlight primary research from the past 3-5 years involving functional interrogation of alternative splicing in rodent and human liver, using both large-scale transcriptomic and focused mechanistic approaches. Because this is a rapidly advancing field, we anticipate that it will be transformative for the future of basic liver biology, as well as HCC diagnosis and management.

Downregulation of miR-193a-3p is involved in the pathogenesis of hepatocellular carcinoma by targeting CCND1

Background

Hepatocellular carcinoma (HCC) is the second-highest cause of malignancy-related death worldwide, and many physiological and pathological processes, including cancer, are regulated by microRNAs (miRNAs). miR-193a-3p is an anti-oncogene that plays an important part in health and disease biology by interacting with specific targets and signals.

Methods

In vitro assays were performed to explore the influences of miR-193a-3p on the propagation and apoptosis of HCC cells. The sequencing data for HCC were obtained from The Cancer Genome Atlas (TCGA), and the expression levels of miR-193a-3p in HCC and non-HCC tissues were calculated. The differential expression of miR-193a-3p in HCC was presented as standardized mean difference (SMD) with 95% confidence intervals (CIs) in Stata SE. The impact of miR-193a-3p on the prognoses of HCC patients was determined by survival analysis. The potential targets of miR-193a-3p were then predicted using miRWalk 2.0 and subjected to enrichment analyses, including Gene Ontology (GO) annotation, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, and Protein-Protein Interaction (PPI) network analysis. The interaction between miR-193a-3p and one predicted target, Cyclin D1 (CCND1), was verified by dual luciferase reporter assays and Pearson correlation analysis.

Results

MiR-193a-3p inhibited the propagation and facilitated the apoptosis of HCC cells in vitro. The pooled SMD indicated that miR-193a-3p had a low level of expression in HCC (SMD: −0.88, 95% CI [−2.36 −0.59]). Also, HCC patients with a higher level of miR-193a-3p expression tended to have a favorable overall survival (OS: HR = 0.7, 95% CI [0.43–1.13], P = 0.14). For the KEGG pathway analysis, the most related pathway was “proteoglycans in cancer”, while the most enriched GO term was “protein binding”. The dual luciferase reporter assays demonstrated the direct interaction between miR-193a-3p and CCND1, and the Pearson correlation analysis suggested that miR-193a-3p was negatively correlated with CCND1 in HCC tissues (R =  − 0.154, P = 0.002).

Conclusion

miR-193a-3p could suppress proliferation and promote apoptosis by targeting CCND1 in HCC cells. Further, miR-193a-3p can be used as a promising biomarker for the diagnosis and treatment of HCC in the future.

The emerging role of microRNAs and long noncoding RNAs in drug resistance of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common malignancy worldwide and the second most lethal human cancer. A portion of patients with advanced HCC can significantly benefit from treatments with sorafenib, adriamycin, 5-fluorouracil and platinum drugs. However, most HCC patients eventually develop drug resistance, resulting in a poor prognosis. The mechanisms involved in HCC drug resistance are complex and inconclusive. Human transcripts without protein-coding potential are known as noncoding RNAs (ncRNAs), including microRNAs (miRNAs), small nucleolar RNAs (snoRNAs), long noncoding RNAs (lncRNAs) and circular RNA (circRNA). Accumulated evidences demonstrate that several deregulated miRNAs and lncRNAs are important regulators in the development of HCC drug resistance which elucidates their potential clinical implications. In this review, we summarized the detailed mechanisms by which miRNAs and lncRNAs affect HCC drug resistance. Multiple tumor-specific miRNAs and lncRNAs may serve as novel therapeutic targets and prognostic biomarkers for HCC.

Plasma miR-146a predicts serological conversion of hepatitis B e-antigen (HBeAg) in chronic hepatitis B patients treated with nucleotide analogs

Background

To investigate the association of plasma miR-146a with serological conversion of hepatitis B e-antigen (HBeAg) in patients with chronic hepatitis B (CHB) treated with nucleotide analogs (NAs).

Methods

This was a retrospective study of 115 HBeAg-positive patients with CHB treated at Xiangya Hospital, Central South University, Changsha, China, between September 2009 and March 2014. Patients were grouped according to whether they had achieved seroconversion of HBeAg by 104 weeks of NAs treatment. We assessed plasma miR-146a using miScript polymerase chain reaction (PCR). Serum alanine transaminase (ALT), hepatitis B virus (HBV) deoxyribonucleic acid (DNA) load, hepatitis B surface antigen (HBsAg) titer, HBeAg titer, and plasma miR-146a were measured at 0, 24, 48, and 104 weeks of treatment. Finally, we also determined ΔmiR-146a_24w and ΔmiR-146a_48w.

Results

ΔmiR-146a_48w was independently associated with seroconversion of HBeAg at 104 weeks [odds ratio (OR) =1.302; 95% confidence interval (CI), 1.159-1.962; P=0.029]. We obtained an area under the receiver operating characteristic (ROC) curve (AUC) of ΔmiR-146_48w of 0.757 for seroconversion of HBeAg (P=0.013). At the optimal cutoff value equivalent to a Youden index of 67.9%, the specificity and sensitivity of ΔmiR-146_48w were 63.7% and 88.3%, respectively. Positive (PPV) and negative (NPV) predictive values were 70.87% and 84.48%, respectively.

Conclusions

ΔmiR-146a_48w was independently associated with seroconversion of HBeAg in CHB patients treated with NAs.

Downregulation of long non-coding RNA nuclear enriched abundant transcript 1 promotes cell proliferation and inhibits cell apoptosis by targeting miR-193a in myocardial ischemia/reperfusion injury

Background

This study aimed to investigate the effect of long non-coding RNA nuclear enriched abundant transcript 1 (lnc-NEAT1) on cell proliferation and apoptosis in myocardial ischemia/reperfusion (I/R) injury cells, and explore its target miRNAs.

Methods

H9c2 cells were cultured in oxygen and glucose deprivation followed by reperfusion (OGD/R) condition to construct a myocardial I/R injury model. Blank shRNA and lnc-NEAT1 shRNA were transferred into normal H9c2 cells and I/R injury H9c2 cells as Normal&sh-NC, OGD/R&sh-NC and OGD/R&sh-NEAT1 groups. Rescue experiment was performed by transfection of NC inhibitor plasmids, miR-193a inhibitor plasmids and NEAT1 shRNA into I/R injury cardiocytes. RNA expression, cell proliferation and cell apoptosis rate were detected by qPCR, CCK-8 and AV/PI respectively.

Results

After OGD/R induction, H9c2 cell apoptosis was greatly increased while cell proliferation was decreased, which indicated successful establishment of myocardial I/R injury model, and lnc-NEAT1 expression was elevated as well. Cell proliferation rate was increased in OGD/R&sh-NEAT1 group at 48 h and 72 h compared to OGD/R&sh-NC group, while cell apoptosis was reduced in OGC/R&sh-NEAT1 group compared to OGD/R&sh-NC group. Target miRNAs detection indicated the negative regulation of lnc-NEAT1 on miR-193a but not miR-182 or miR-141. In rescue experiment, downregulation of lnc-NEAT1 promoted cell proliferation and inhibited cell apoptosis through targeting miR-193a in I/R injury H9c2 cells.

Conclusion

Lnc-NEAT1 is overexpressed in myocardial I/R injury cells compared to normal myocardial cells, and downregulation of lnc-NEAT1 enhances cell proliferation while inhibits cell apoptosis through targeting miR-193a in I/R injury H9c2 cells.

Exploration of bladder cancer-associated methylated miRNAs by methylated DNA immunoprecipitation sequencing

BACKGROUND

The current study aimed to explore the association between two epigenomic components, miRNA and DNA methylation, in bladder cancer (BC).

METHODS

Eight paired samples of tumor tissue and matched adjacent normal tissues from BC patients were subjected to methylated DNA immunoprecipitation sequencing and sRNA-Seq for differentially methylated miRNA genes and differential miRNA analysis. The miRNAs regulated by DNA methylation were screened and their functions involved in BC were analyzed using Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) as well as a miRNA-mRNA interaction network.

RESULTS

The methylation levels of 212 genes were different between tumors and normal tissues with specific enrichment at transcription initiation and termination sites. Among these genes, 154 were hypermethylated and 58 were hypomethylated. GO and KEGG pathway enrichment analysis indicated that differentially methylated miRNA genes were mainly enriched in tumor-associated GO terms and signaling pathways. Pairwise statistical analysis of MeDIP-Seq and sRNA-Seq data showed that there are 154 and 165 candidate methylation-regulated genes in tumors and normal tissues, respectively. Notably, an interaction network indicated that the miRNAs regulated by methylation regulated a broad range of mRNAs associated with cancer development and progression. In particular, the most differentially expressed miRNAs were validated by qRT-PCR, such that miR-145-5p was downregulated and miR-182-5p was upregulated in patients with bladder cancer.

CONCLUSION

A large number of miRNA genes were modified by methylation in BC. Identification of changes in the expression of these miRNAs provides a great deal of important information for BC diagnosis.

Dietary vinegar prevents kidney stone recurrence via epigenetic regulations

BACKGROUND

Epidemiological evidence of over 9000 people suggests that daily intake of vinegar whose principal bioactive component is acetic acid is associated with a reduced risk of nephrolithiasis. The underlying mechanism, however, remains largely unknown.

METHODS

We examined the in vitro and in vivo anti-nephrolithiasis effects of vinegar and acetate. A randomized study was performed to confirm the effects of vinegar in humans.

FINDINGS

We found individuals with daily consumption of vinegar compared to those without have a higher citrate and a lower calcium excretion in urine, two critical molecules for calcium oxalate (CaOx) kidney stone in humans. We observed that oral administration of vinegar or 5% acetate increased citrate and reduced calcium in urinary excretion, and finally suppressed renal CaOx crystal formation in a rat model. Mechanism dissection suggested that acetate enhanced acetylation of Histone H3 in renal tubular cells and promoted expression of microRNAs-130a-3p, -148b-3p and -374b-5p by increasing H3K9, H3K27 acetylation at their promoter regions. These miRNAs can suppress the expression of Nadc1 and Cldn14, thus enhancing urinary citrate excretion and reducing urinary calcium excretion. Significantly these mechanistic findings were confirmed in human kidney tissues, suggesting similar mechanistic relationships exist in humans. Results from a pilot clinical study indicated that daily intake of vinegar reduced stone recurrence, increased citrate and reduced calcium in urinary excretion in CaOx stone formers without adverse side effects.

INTERPRETATION

Vinegar prevents renal CaOx crystal formation through influencing urinary citrate and calcium excretion via epigenetic regulations. Vinegar consumption is a promising strategy to prevent CaOx nephrolithiasis occurrence and recurrence. FUND: National Natural Science Foundations of China and National Natural Science Foundation of Guangdong Province.

Identification of a 3,3-difluorinated tetrahydropyridinol compound as a novel antitumor agent for hepatocellular carcinoma acting via cell cycle arrest through disturbing CDK7-mediated phosphorylation of Cdc2

Tetrahydropyridinol derivatives were recently reported to exhibit good biological activities, and the incorporation of fluorine into organic molecules may have profound effects on their physical and biological properties. Therefore, we investigated the anticancer activities of six fluorinated tetrahydropyridinol derivatives that we synthesized previously. We found that only one compound, 3,3-difluoro-2,2-dimethyl-1,6-diphenyl-5-tosyl-1,2,3,6-tetrahydropyridin-4-ol, showed significant antiproliferative activity on human hepatocellular carcinoma HepG2 and HMCCLM3 cells (the IC₅₀ values were 21.25 and 29.07 μM, respectively). We also found that this compound mediated cell cycle arrest in the G0/G1 phase at 30-40 μM. Western blot analysis demonstrated that the cell cycle arrest induced by this compound in HepG2 and HMCCLM3 cells was associated with a significant decrease in Cdc2 and cyclin B1, which led to the accumulation of the phosphorylated-Tyr¹⁵ (inactive) form of Cdc2 and low expression of M phase-promoting factor (cyclin B1/Cdc2). Moreover, cells treated with this compound exhibited decreased expression of cyclin-dependent kinase (CDK)-activating kinase (CDK7/cyclin H). This compound also induced cell apoptosis via activation of caspase-3. A xenograft model in nude mice demonstrated anti-liver cancer activity and the mechanism of action of this compound. These findings indicated that the anticancer effect of this compound was partially due to G0/G1 cell cycle arrest via inhibition of CDK7-mediated expression of Cdc2, and this compound may be a promising anticancer candidate for further investigation.

MiR-193a regulates chemoresistance of human osteosarcoma cells via repression of IRS2

Chemoresistance prevents curative potential of chemotherapy in most cases. MicroRNAs (miRNAs) are key players in regulating chemoresistance in osteosarcoma, which is the most common primary bone cancer. Bisulfite sequencing and quantitative real time PCR analyses showed that miR-193a expression is downregulated by DNA hypermethylation at its promoter region in a chemoresistant cell line, SJSA-1, compared to a chemosensitive cell line G-292. Introduction of a miR-193a mimic in SJSA-1 cells or an antagomir into G-292 cells confirmed the role of miR-193a in osteosarcoma chemoresistance. Bioinformatics together with biochemical assays showed that insulin receptor substrate 2 (IRS2) is a target of miR-193a. Our data concludes that miR-193a plays a role in the osteosarcoma chemoresistance and thus might serve as a useful biomarker for osteosarcoma prognosis.

DNA methylation of shelf, shore and open sea CpG positions distinguish high microsatellite instability from low or stable microsatellite status colon cancer stem cells

Aim: To investigate the genome-wide methylation of genetically characterized colorectal cancer stem cell (CR-CSC) lines. Materials & methods: Eight CR-CSC lines were isolated from primary colorectal cancer (CRC) tissues, cultured and characterized for aneuploidy, mutational status of CRC-related genes and microsatellite instability (MSI). Genome-wide DNA methylation was assessed by MethylationEPIC microarray. Results: We describe a distinctive methylation pattern that is maintained following in vivo passages in immune-compromised mice. We identified an epigenetic CR-CSC signature associated with MSI. We noticed that the preponderance of the differentially methylated positions do not reside at CpG islands, but spread to shelf and open sea regions. Conclusion: Given that CRCs with MSI-high status have a lower metastatic potential, the identification of a MSI-related methylation signature could provide new insights and possible targets into metastatic CRC.

ncRNAs associated with drug resistance and the therapy of digestive system neoplasms

Digestive system cancer remains a common cancer and the main cause of cancer-related death worldwide. Drug resistance is a major challenge in the therapy of digestive system cancer, and represents a primary obstacle in the treatment of cancer by restricting the efficiency of both traditional chemotherapy and biological therapies. Existing studies indicate that noncoding RNAs play an important role in the evolution and progression of drug resistance in digestive system cancer, mainly by modulating drug transporter-related proteins, DNA damage repair, cell-cycle-related proteins, cell apoptosis-related proteins, drug target-related proteins, and the tumor microenvironment. In this review, we address the potential mechanisms of ncRNAs underlying drug resistance in digestive system tumors and discuss the possible application of ncRNAs against drug resistance in digestive system tumors.

miR-193: A new weapon against cancer

microRNAs (miRNAs) are known as a large group of short noncoding RNAs, which structurally consist of 19-22 nucleotides in length and functionally act as one of the main regulators of gene expression in important biological and physiological contexts like cell growth, apoptosis, proliferation, differentiation, movement (cell motility), and angiogenesis as well as disease formation and progression importantly in cancer cell invasion, migration, and metastasis. Among these notable tiny molecules, many studies recently presented the important role of the miR-193 family comprising miR-193a-3p, miR-193a-5p, miR-193b-3p, and miR-193b-5p in health and disease biological processes by interaction with special targeting and signaling, which mainly contribute as a tumor suppressor. Therefore, in the present paper, we review the functional role of this miRNA family in both health and disease conditions focusing on various tumor developments, diagnoses, prognoses, and treatment.

The role and mechanisms of action of microRNAs in cancer drug resistance

MicroRNAs (miRNAs) are small non-coding RNAs with a length of about 19–25 nt, which can regulate various target genes and are thus involved in the regulation of a variety of biological and pathological processes, including the formation and development of cancer. Drug resistance in cancer chemotherapy is one of the main obstacles to curing this malignant disease. Statistical data indicate that over 90% of the mortality of patients with cancer is related to drug resistance. Drug resistance of cancer chemotherapy can be caused by many mechanisms, such as decreased antitumor drug uptake, modified drug targets, altered cell cycle checkpoints, or increased DNA damage repair, among others. In recent years, many studies have shown that miRNAs are involved in the drug resistance of tumor cells by targeting drug-resistance-related genes or influencing genes related to cell proliferation, cell cycle, and apoptosis. A single miRNA often targets a number of genes, and its regulatory effect is tissue-specific. In this review, we emphasize the miRNAs that are involved in the regulation of drug resistance among different cancers and probe the mechanisms of the deregulated expression of miRNAs. The molecular targets of miRNAs and their underlying signaling pathways are also explored comprehensively. A holistic understanding of the functions of miRNAs in drug resistance will help us develop better strategies to regulate them efficiently and will finally pave the way toward better translation of miRNAs into clinics, developing them into a promising approach in cancer therapy.

MiR-139-5p, miR-940 and miR-193a-5p inhibit the growth of hepatocellular carcinoma by targeting SPOCK1

The study was aimed to screen out miRNAs with differential expression in hepatocellular carcinoma (HCC), and to explore the influence of the expressions of these miRNAs and their target gene on HCC cell proliferation, invasion and apoptosis. MiRNAs with differential expression in HCC were screened out by microarray analysis. The common target gene of these miRNAs (miR‐139‐5p, miR‐940 and miR‐193a‐5p) was screened out by analysing the target genes profile (acquired from Targetscan) of the three miRNAs. Expression levels of miRNAs and SPOCK1 were determined by quantitative real time polymerase chain reaction (qRT‐PCR). The target relationships were verified by dual luciferase reporter gene assay and RNA pull‐down assay. Through 3‐(4,5‐dimethyl‐2‐thiazolyl)‐2,5‐diphenyl‐2‐H‐tetrazolium bromide,thiazolyl blue tetrazolium bromide (MTT) and transwell assays and flow cytometry, HCC cell viability, invasion and apoptosis were determined. In vivo experiment was conducted in nude mice to investigate the influence of three miRNAs on tumour growth. Down‐regulation of miR‐139‐5p, miR‐940 and miR‐193a‐5p was found in HCC. Overexpression of these miRNAs suppressed HCC cell viability and invasion, promoted apoptosis and inhibited tumour growth. SPOCK1, the common target gene of miR‐139‐5p, miR‐940 and miR‐193a‐5p, was overexpressed in HCC. SPOCK1 overexpression promoted proliferation and invasion, and restrained apoptosis of HCC cells. MiR‐139‐5p, miR‐940 and miR‐193a‐5p inhibited HCC development through targeting SPOCK1.

Insights into the roles of miRNAs; miR-193 as one of small molecular silencer in osteosarcoma therapy

Today, cancer is one of the most common causes of death. Osteosarcoma (OS) is a tumor in long bones and its prevalence is high in teenagers and young people. Among the methods that used to treat cancer, one can name chemotherapy, surgery, and radiotherapy. Since these methods have some disadvantages and they are not absolutely successful, the use of microRNAs (miRNAs) is very useful in diagnosis and treatment of OS. MiRNAs are small non-coding RNA molecules, containing 18-25 nucleotides, which are involved in the regulation of gene expression via binding to messenger RNA (mRNA). These RNAs are divided into two classes of suppressors and oncogenes. During OS, there is aberrant expression of several miRNAs. Among these miRNAs are downregulation of miR-193 that has been associated with cancer occurrence. The aim of the current manuscript is to have overview on the treatment approaches of OS with special focus on miR-193.

Upregulated microRNA-193a-3p is responsible for cisplatin resistance in CD44(+) gastric cancer cells

Cisplatin is a well‐known anticancer drug used to treat various cancers. However, development of cisplatin resistance has hindered the efficiency of this drug in cancer treatment. Development of chemoresistance is known to involve many signaling pathways. Recent attention has focused on microRNAs (miRNAs) as potentially important upstream regulators in the development of chemoresistance. CD44 is one of the gastric cancer stem cell markers and plays a role in regulating self‐renewal, tumor initiation, metastasis and chemoresistance. The purpose of the present study was to examine the mechanism of miRNA‐mediated chemoresistance to cisplatin in CD44‐positive gastric cancer stem cells. We sorted gastric cancer cells according to level of CD44 expression by FACS and analyzed their miRNA expression profiles by microarray analysis. We found that miR‐193a‐3p was significantly upregulated in CD44(+) cells compared with CD44(−) cells. Moreover, SRSF2 of miR‐193a‐3p target gene was downregulated in CD44(+) cells. We studied the modulation of Bcl‐X and caspase 9 mRNA splicing by SRSF2 and found that more pro‐apoptotic variants of these genes were generated. We also found that downstream anti‐apoptotic genes such as Bcl‐2 were upregulated, whereas pro‐apoptotic genes such as Bax and cytochrome C were downregulated in CD44(+) cells compared to CD44(−) cells. In addition, we found that an elevated level of miR‐193a‐3p triggered the development of cisplatin resistance in CD44(+) cells. Inhibition of miR‐193a‐3p in CD44(+) cells increased SRSF2 expression and also altered the levels of multiple apoptotic genes. Furthermore, inhibition of miR‐193a‐3p reduced cell viability and increased the number of apoptotic cells. Therefore, miR‐193a‐3p may be implicated in the development of cisplatin resistance through regulation of the mitochondrial apoptosis pathway. miR‐193a‐3p could be a promising target for cancer therapy in cisplatin‐resistant gastric cancer.

Epigenetically regulated miR-1247 functions as a novel tumour suppressor via MYCBP2 in methylator colon cancers

Background

Colorectal cancer (CRC) is a heterogeneous disease with distinct clinical subsets based on underlying genetic and epigenetic changes. DNA hypermethylation yields a unique CRC subset with a distinct phenotype and clinical behaviour, but this oncogenic pathway is not fully characterised. This study identifies and characterises miR-1247 as a novel tumour suppressor microRNA in methylated human colon cancers.

Method

Tumour samples from patients with hypermethylated and non-methylated colon cancer and cell lines were evaluated for miR-1247 expression and function. A murine subcutaneous xenograft model was used for in vivo functional studies.

Results

miR-1247 was methylated and underexpressed in methylator colon cancers. Overexpression of miR-1247 significantly inhibited cell proliferation, decreased tumour cell motility, induced apoptosis, and mitigated tumour formation capacity both in vivo and in vitro. Pharmacologic demethylation increased miR-1247 expression and produced similar anti-tumour activities. Mechanistic investigations revealed that MYCBP2, a member of the c-myc oncogene family, is a direct functional target of miR-1247. Furthermore, in CRC patients, MYCBP2 protein levels are associated with miR-1247 levels and survival.

Conclusions

miR-1247 acts as a tumour suppressor by inhibiting MYCBP2 in methylator colon cancer. The MYCBP2/c-myc axis may underlie the anti-tumour activities of miR-1247 and is a potential therapeutic target via demethylation agents.

Non-coding RNA in drug resistance of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) has been one of the most highly lethal cancers. The acquisition of drug resistance accounts for the majority of poor effects of chemotherapy in HCC. Non-coding RNAs (ncRNAs) including miRNAs, long ncRNAs (lncRNAs), and circular RNA (circRNA) have been well-documented to participate in cancer occurrence and progression. Recently, multiple studies have highlighted the key roles of ncRNAs in chemoresistance of HCC. In addition, accumulating evidence has demonstrated that they can serve as biomarkers in diagnosis, treatment, and prognosis of HCC. In this review, we first overviewed up-to-date findings regarding miRNA and lncRNA in drug resistance of HCC, then summarized specific mechanisms that they modulate chemoresistance of HCC, and finally discussed their potential clinical application in overcoming the obstacle of HCC chemoresistance in the future.

Serine/arginine rich splicing factor 2 expression and clinic pathological features indicating a prognostic factor in human hepatocellular carcinoma patients

BACKGROUND

This research was aimed to study the expression of Serine/arginine rich splicing factor 2 (SRSF2) in tissues of hepatocellular carcinoma, and explore the relationship between the expression and the clinic pathological and prognosis of human hepatocellular carcinoma (HCC).

METHODS

One hundred and fifty-three pairs HCC tissues and adjacent normal tissue were collected from January 2010 to March 2013. The expression of SRSF2 gene was detected by immunohistochemistry, western blotting and real-time quantitative polymerase chain reaction (PCR), and the relationship between the expression and the clinic pathological and prognosis of HCC being analyzed.

RESULTS

In 153 cases of hepatocellular carcinoma, SRSF2 was highly expressed in 93 cases, low expression of 60 cases, immunohistochemistry score (6.50 ± 2.82), which was significantly higher than that in adjacent normal tissues (2.94 ± 1.23) (P< 0.05). The expression of SRSF2 in HCC was not associated with gender (χ2= 0.014, P= 0.906), age (χ2= 0.007, P= 0.931), tumor size (χ2= 3.566, P= 0.059) and T stage (χ2= 2.708, P= 0.100), and was significantly correlated with tumor differentiation (χ2= 9.687, P= 0.007), lymph node metastasis (χ2= 4.827, P= 0.028), distal metastasis (χ2= 9.235, P= 0.002), tumor, node, metastasis (TNM) stage (χ2= 3.978, P= 0.046), portal vein invasion and serum alpha-fetoprotein (χ2= 14.919, P= 0.000). The expression of SRSF2 protein in hepatocellular carcinoma was positively correlated (r = 0.704, P< 0.05) with serum alpha-fetoprotein through Pearson analysis. The survival rates of SRSF2 overexpressing hepatocellular carcinoma were 74.19%, 44.09%, 26.88%, 24.73% and 21.51% at 1 year, 2 years, 3 years, 4 years and 5 years respectively, which were lower than those of SRSF2 low expression group (93.33%, 71.67%, 56.67%, 51.67% and 50.00%).

CONCLUSION

SRSF2 is highly expressed in hepatocellular carcinoma and its expression increases with the degree of tumor differentiation and TNM staging. It is related to lymph node metastasis and metastasis of tumor cells, and is positively related to serum alpha fetoprotein content, and affects the postoperative survival time of HCC patients.

The LncRNA H19/miR-193a-3p axis modifies the radio-resistance and chemotherapeutic tolerance of hepatocellular carcinoma cells by targeting PSEN1

This study was designated to verify if the lncRNA H19/miR-193a-3p axis would play a regulatory role in the radio-/chemo-resistances of HCC cells through targeting PSEN1. Within the study, five human HCC cell lines were prepared, including Bel-7402, HepG2, Hep3b, QGY-7703, and SMMC-7721. Moreover, docetaxel (DT), paclitaxel (Pt), vinorelbine (Vb), and 5-fluorouracil (5-Fu) were managed as the chemo-therapeutics, and single-dose X-rays were performed as radio-therapies. Besides, lncRNA H19 and miR-193a-3p were detected by qRT-PCR and Western blot were implemented to quantify the expressional levels of PSEN1, Ku80, γ-H2AX, and RAD51. Luciferase reporter gene assay was advanced to verify the targeted relationship between lncRNA H19 and miR-193a-3p. As a consequence, QGY-7703 and Bel-7402 were, respectively, the most radiation-sensitive and radiation-proof cell lines, and Bel-7402 was associated with the highest resistances to DT, Pt, Vb, and 5-FU. The restrained lncRNA H19 and over-expressed miR-193a-3p expressions tended to significantly elevate the survival rate and proliferation of Bel-7402 cells, when they were exposed to radiation and subject to chemo-therapies. The lncRNA H19 was also found to directly target miR-193a-3p in inducing the HCC development. PSEN1 appeared to be subject to the modification of lncRNA H19 and miR-193a-3p in its acting on the survival rates and proliferative abilities of HCC cells. The lncRNA H19/miR-193a-3p/PSEN1 axis could be regarded as the treatment targets for HCC, so as to further improve the treatment efficacy of chemo- and radio-therapies for HCC.

Resistance a major hindrance to chemotherapy in hepatocellular carcinoma: an insight

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer mortality, accounting for almost 90% of total liver cancer burden. Surgical resection followed by adjuvant and systemic chemotherapy are the most meticulously followed treatment procedures but the complex etiology and high metastatic potential of the disease renders surgical treatment futile in majority of the cases. Another hindrance to the scenario is the acquired resistance to drugs resulting in relapse of the disease. Hence, to provide insights into development of novel therapeutic targets and diagnostic biomarkers, this review focuses on the various molecular mechanisms underlying chemoresistance in HCC. We have provided a comprehensive summary of the various strategies adopted by HCC cells, extending from apoptosis evasion, autophagy activation, drug expulsion to epigenetic transformation as modes of therapy resistance. The role of stem cells in imparting chemoresistance is also discussed. Furthermore, the review also focuses on how this knowledge might be exploited for the development of an effective, prospective therapy against HCC.

Clinical and biological significance of miR-23b and miR-193a in human hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common cancer of the liver with a very poor prognosis. The dysregulation of microRNAs (miRs) is indeed implicated in HCC onset and progression. In this study, we have evaluated the expression of miR-23b and miR-193a in a large cohort of 59 and 67 HCC patients, respectively. miR-23b and miR-193a resulted significantly down-regulated in primary HCCs compared to their matched peritumoral counterparts. Furthermore, patients with higher miR-193a expression exhibited longer OS and DFS, suggesting that miR-193a may be a molecular prognostic factor for HCC patients. Since the regulation of miRs by DNA methylation may occur in human cancers, we verified whether the down-modulation of miR-23b and miR-193a in HCC tissues could be related to DNA methylation. An inverse trend between miR-23b expression and DNA methylation was observed, indicating that miR-23b can be epigenetically regulated. By contrast, the down-regulation of miR-193a was not mediated by DNA methylation. To verify the potential role of miR-23b and miR-193a as responsive molecular targets in vitro, we used the inhibitor of DNA methylation 5-aza-dC to restore miR-23b expression level in combination with miR-193a transfection. The combined treatment led to a significant inhibition of cellular proliferation and migration. Taken together, our findings provide evidence that miR-23b and miR-193a may be molecular diagnostic and prognostic factors for HCC; furthermore, miR-23b and miR-193a are responsive molecular targets for limiting HCC cell aggressiveness in combination with the epigenetic drug 5-aza-dC. Moreover, our results provide new advances in the epigenetic regulation of these miRs in HCC.

Epigenetics and MicroRNAs in Cancer

The ability to reprogram the transcriptional circuitry by remodeling the three-dimensional structure of the genome is exploited by cancer cells to promote tumorigenesis. This reprogramming occurs because of hereditable chromatin chemical modifications and the consequent formation of RNA-protein-DNA complexes that represent the principal actors of the epigenetic phenomena. In this regard, the deregulation of a transcribed non-coding RNA may be both cause and consequence of a cancer-related epigenetic alteration. This review summarizes recent findings that implicate microRNAs in the aberrant epigenetic regulation of cancer cells.

Clinical and biological significance of miR-193a-3p targeted KRAS in colorectal cancer pathogenesis

This study was to investigate the expression pattern, mechanisms and clinicopathological implications of miR-193a-3p in colorectal cancer. Fresh-frozen tissues from 70 matched colorectal adenocarciomas and the adjacent non-neoplastic mucosae were prospectively collected. Two colorectal cancer cell lines (SW480 and SW48) and a non-neoplastic colon cell line (FHC) were also used. The expression levels of miR193a-3p in the cells and tissues were measured by quantitative real-time polymerase chain reaction. The expression of KRAS protein as a predicted downstream target for miR-193a was studied by immunohistochemistry. Restoration of the miR-193a level in the cell lines by permanent transfection was achieved and multiple functional and immunological assays were performed to analyze the functions of miR-193a in vitro. Down-regulation of miR-193a-3p was noted in 70% of the colorectal cancer tissues when compared to non-neoplastic colorectal tissues. In addition, down-regulation of miR-193a was significantly correlated with carcinoma of early stages (P<.05). Significant inverse correlation between miR-193a-3p and its target KRAS protein was determined (P<.05). Overexpression of miR-193a in colon cancer cells resulted in reduced cell proliferation, increased apoptosis, induced significant changes in cell cycle events and decreased the expression of epithelial-mesenchymal transition marker TWIST. This study confirms the tumor suppressor roles of miR-193a-3p, its downstream target affinity to KRAS and clinical significance in patients with colorectal adenocarcinoma.

Involvement of aberrantly activated HOTAIR/EZH2/miR-193a feedback loop in progression of prostate cancer

Background

Though androgen deprivation therapy is the standard treatment for prostate cancer (PCa), most patients would inevitably progress to castration-resistant prostate cancer (CRPC) which is the main cause of PCa death. Therefore, the identification of novel molecular mechanism regulating cancer progression and achievement of new insight into target therapy would be necessary for improving the benefits of PCa patients. This study aims to study the function and regulatory mechanism of HOTAIR/EZH2/miR-193a feedback loop in PCa progression.

Methods

MSKCC and TCGA datasets were used to identify miR-193a expression profile in PCa. Cell Counting Kit-8 (CCK-8) assays, colony formation, invasion, migration, flow cytometry, a xenograft model and Gene Set Enrichment Analysis were used to detect and analyze the biological function of miR-193a. Then, we assessed the role of HOTAIR and EZH2 in regulation of miR-193a expression by using plasmid, lentivirus and small interfering RNA (siRNA). Luciferase reporter assays and chromatin immunoprecipitation assays were performed to detect the transcriptional activation of miR-193a by EZH2 and HOTAIR. Further, qRT-PCR and luciferase reporter assays were conducted to examine the regulatory role of miR-193a controlling the HOTAIR expression in PCa. Finally, the correlation between HOTAIR, EZH2 and miR-193a expression were analyzed using In situ hybridization and immunohistochemistry.

Results

We found that miR-193a was significantly downregulated in metastatic PCa through mining MSKCC and TCGA datasets. In vitro studies revealed that miR-193a inhibited PCa cell growth, suppressed migration and invasion, and promoted apoptosis; in vivo results demonstrated that overexpression of miR-193a mediated by lentivirus dramatically reduced PCa xenograft tumor growth. Importantly, we found EZH2 coupled with HOTAIR to repress miR-193a expression through trimethylation of H3K27 at miR-193a promoter in PC3 and DU145 cells. Interestingly, further evidence illustrated that miR-193a directly targets HOTAIR showing as significantly reduced HOTAIR level in miR-193a overexpressed cells and tissues. The expression level of miR-193a was inversely associated with that of HOTAIR and EZH2 in PCa.

Conclusion

This study firstly demonstrated that miR-193a acted as tumor suppressor in CRPC and the autoregulatory feedback loop of HOTAIR/EZH2/miR-193a served an important mechanism in PCa development. Targeting this aberrantly activated feedback loop may provide a potential therapeutic strategy.

Electronic supplementary material

The online version of this article (doi: 10.1186/s13046-017-0629-7) contains supplementary material, which is available to authorized users.

MicroRNA-193a inhibits breast cancer proliferation and metastasis by downregulating WT1

In many cancers, microRNA-193a (miR-193a) is a suppressor miRNA, but its underlying anti-oncogenic activity in breast cancer is not known. In this study, we found decreased miR-193a (specifically, miR-193a-5p) expression not only in breast cancer cell lines but also in breast cancer tissues as compared with the adjacent non-tumor tissues. Ectopic miR-193a overexpression inhibited the proliferation, colony formation, migration, and invasion of MDA-MB-231 and BT549 cells. miR-193a reduced Wilms’ tumor 1 (WT1) expression and repressed luciferase reporter activity by binding WT1 coding region sequences; mutation of the predicted miR-193a binding site abolished this effect. miR-193a and WT1 expression were significantly inversely correlated in breast cancer tissues. Importantly, the anti-cancer activity induced by miR-193a was partially reversed by WT1 overexpression, indicating an important role for WT1 in such activity related to miR-193a. Our results reveal that miR-193a-WT1 interaction plays an important role in breast cancer metastasis, and suggest that restoring miR-193a expression is a therapeutic strategy in breast cancer.

Biological Function of MicroRNA193a-3p in Health and Disease

MicroRNAs (miRNAs) are a class of small noncoding RNAs that act mainly as negative regulators of gene expression. Several studies demonstrated that miRNAs take part in numerous biological processes, such as proliferation, apoptosis, and migration. The dysregulation of miRNAs has been frequently observed in different types of disease, including cancer. Here, we provide a comprehensive review on the human miR-193a-3p by considering its role in both physiological and pathological contexts. Different mechanisms involved in regulating miR-193a-3p expression have been reported, including epigenetic modifications and transcription factors. In physiological contexts, miR-193a-3p seemed able to limit proliferation and cell cycle progression in normal cells. Remarkably, several publications demonstrated that miR-193a-3p acted as a tumor suppressor miRNA in cancer by targeting different genes involved in proliferation, apoptosis, migration, invasion, and metastasis. Furthermore, the downregulation of miR-193a-3p has been observed in many primary tumors and altered levels of circulating miR-193a-3p have been identified in serum or plasma of cancer patients and subjects affected by Parkinson's disease or by schizophrenia. In a clinical perspective, further studies are needed to explore the antitumor effects of the miR-193a-3p mimics delivery and the relevance of this miRNA detection as a possible diagnostic and prognostic biomarker.

Downregulation of miR-193a-3p inhibits cell growth and migration in renal cell carcinoma by targeting PTEN

Although miR-193a-3p has been found to be dysregulated in variety of human tumors, little is known about its role in renal cell carcinoma. This study was designed to investigate the function and underlying mechanism of miR-193a-3p in human renal cell carcinoma tissues and cell lines. Here, we demonstrated that the expression of miR-193-3p was increased in renal cell carcinoma tissues and cell lines. In addition, knockdown of miR-193a-3p significantly inhibited cell proliferation and colony formation and induced cells into G1 phase arrest. Meanwhile, the migration potential of 786-O cells was also decreased compared to control group. Furthermore, we identified PTEN as a direct and functional target of miR-193a-3p, at least partly responsible for promoting tumor effect of miR-193a-3p in renal cell carcinoma. Taken together, the findings indicated for the first time that miR-193a-3p functions as a tumor-promoting microRNA by directly targeting PTEN in renal cell carcinoma.

New Insights into the Epigenetics of Hepatocellular Carcinoma

Hepatocellular Carcinoma (HCC) is one of the most predominant malignancies with high fatality rate. This deadly cancer is rising at an alarming rate because it is quite resistant to radio- and chemotherapy. Different epigenetic mechanisms such as histone modifications, DNA methylation, chromatin remodeling, and expression of noncoding RNAs drive the cell proliferation, invasion, metastasis, initiation, progression, and development of HCC. These epigenetic alterations because of potential reversibility open way towards the development of biomarkers and therapeutics. The contribution of these epigenetic changes to HCC development has not been thoroughly explored yet. Further research on HCC epigenetics is necessary to better understand novel molecular-targeted HCC treatment and prevention. This review highlights latest research progress and current updates regarding epigenetics of HCC, biomarker discovery, and future preventive and therapeutic strategies to combat the increasing risk of HCC.