Has_circ_0008583 modulates hepatocellular carcinoma progression through the miR-1301-3p/METTL3 pathway

RNA modifications in the progression of liver diseases: from fatty liver to cancer

Non-alcoholic fatty liver disease (NAFLD) has emerged as a prominent global health concern associated with high risk of metabolic syndrome, and has impacted a substantial segment of the population. The disease spectrum ranges from simple fatty liver to non-alcoholic steatohepatitis (NASH), which can progress to cirrhosis and hepatocellular carcinoma (HCC) and is increasingly becoming a prevalent indication for liver transplantation. The existing therapeutic options for NAFLD, NASH, and HCC are limited, underscoring the urgent need for innovative treatment strategies. Insights into gene expression, particularly RNA modifications such as N6 methyladenosine (m6A), hold promising avenues for interventions. These modifications play integral roles in RNA metabolism and cellular functions, encompassing the entire NAFLD-NASH-HCC progression. This review will encompass recent insights on diverse RNA modifications, including m6A, pseudouridine (ψ), N1-methyladenosine (m1A), and 5-methylcytidine (m5C) across various RNA species. It will uncover their significance in crucial aspects such as steatosis, inflammation, fibrosis, and tumorigenesis. Furthermore, prospective research directions and therapeutic implications will be explored, advancing our comprehensive understanding of the intricate interconnected nature of these pathological conditions.

Epigenetic regulation of hepatocellular carcinoma progression: MicroRNAs as therapeutic, diagnostic and prognostic factors

Hepatocellular carcinoma (HCC), a significant challenge for public healthcare systems in developed Western countries including the USA, Canada, and the UK, is influenced by different risk factors including hepatitis virus infections, alcoholism, and smoking. The disruption in the balance of microRNAs (miRNAs) plays a vital function in tumorigenesis, given their function as regulators in numerous signaling networks. These miRNAs, which are mature and active in the cytoplasm, work by reducing the expression of target genes through their impact on mRNAs. MiRNAs are particularly significant in HCC as they regulate key aspects of the tumor, like proliferation and invasion. Additionally, during treatment phases such as chemotherapy and radiotherapy, the levels of miRNAs are key determinants. Pre-clinical experiments have demonstrated that altered miRNA expression contributes to HCC development, metastasis, drug resistance, and radio-resistance, highlighting related molecular pathways and processes like MMPs, EMT, apoptosis, and autophagy. Furthermore, the regulatory role of miRNAs in HCC extends beyond their immediate function, as they are also influenced by other epigenetic factors like lncRNAs and circular RNAs (circRNAs), as discussed in recent reviews. Applying these discoveries in predicting the prognosis of HCC could mark a significant advancement in the therapy of this disease.

Diagnostic and therapeutic potentials of methyltransferase-like 3 in liver diseases

Methyltransferase-like 3 (METTL3), a component of the RNA N6-methyladenosine (m6A) modification with a specific catalytic capacity, controls gene expression by actively regulating RNA splicing, nuclear export, stability, and translation, determines the fate of RNAs and assists in regulating biological processes. Studies conducted in recent decades have demonstrated the pivotal regulatory role of METTL3 in liver disorders, including hepatic lipid metabolism disorders, liver fibrosis, nonalcoholic steatohepatitis, and liver cancer. Although METTL3's roles in these diseases have been extensively investigated, the regulatory network of METTL3 and its potential applications remain unexplored. In this review, we provide a comprehensive overview of the roles and mechanisms of METTL3 implicated in these diseases, establish a regulatory network of METTL3, evaluate the potential for targeting METTL3 for diagnosis and treatment, and discuss avenues for future development and research. We found relatively upregulated expressions of METTL3 in these liver diseases, demonstrating its potential as a diagnostic biomarker and therapeutic target.

Non-coding RNA methylation modifications in hepatocellular carcinoma: interactions and potential implications

RNA methylation modification plays a crucial role as an epigenetic regulator in the oncogenesis of hepatocellular carcinoma (HCC). Numerous studies have investigated the molecular mechanisms underlying the methylation of protein-coding RNAs in the progression of HCC. Beyond their impact on mRNA, methylation modifications also influence the biological functions of non-coding RNAs (ncRNAs). Here, we present an advanced and comprehensive overview of the interplay between methylation modifications and ncRNAs in HCC, with a specific focus on their potential implications for the tumor immune microenvironment. Moreover, we summarize promising therapeutic targets for HCC based on methylation-related proteins. In the future, a more profound investigation is warranted to elucidate the effects of ncRNA methylation modifications on HCC pathogenesis and devise valuable intervention strategies. Video Abstract.

New insights into the regulation of METTL3 and its role in tumors

As one of the most abundant epigenetic modifications in RNA, N6-methyladenosine (m6A) affects RNA transcription, splicing, stability, and posttranscriptional translation. Methyltransferase-like 3 (METTL3), a key component of the m6A methyltransferase complex, dynamically regulates target genes expression through m6A modification. METTL3 has been found to play a critical role in tumorigenesis, tumor growth, metastasis, metabolic reprogramming, immune cell infiltration, and tumor drug resistance. As a result, the development of targeted drugs against METTL3 is becoming increasingly popular. This review systematically summarizes the factors that regulate METTL3 expression and explores the specific mechanisms by which METTL3 affects multiple tumor biological behaviors. We aim to provide fundamental support for tumor diagnosis and treatment, at the same time, to offer new ideas for the development of tumor-targeting drugs.

The bidirectional interplay between ncRNAs and methylation modifications in gastrointestinal tumors

The aberrant expression of methylation and ncRNAs, two crucial regulators of epigenetic modifications, has been widely demonstrated in cancer. The complex interplay between them is essential in promoting malignant phenotype, poor prognosis, and drug resistance in GI tumors (including esophageal, gastric, colorectal, liver, and pancreatic cancers). Therefore, we summarize the interrelation process between ncRNAs and methylation modifications in GI tumors, including the detailed mechanism of methylation enzyme regulation of ncRNAs, the molecular mechanism of ncRNAs regulation of methylation modifications, and the correlation between the interactions between ncRNAs and methylation modifications and clinical features of tumors. Finally, we discuss the potential value of ncRNAs and methylation modifications in clinical diagnosis and therapy.

Cancer-associated fibroblast exosomes promote chemoresistance to cisplatin in hepatocellular carcinoma through circZFR targeting signal transducers and activators of transcription (STAT3)/ nuclear factor -kappa B (NF-κB) pathway

Chemoresistance in hepatocellular carcinoma (HCC) has been found to be influenced by exosomal transport of circRNAs. However, the role of circZFR in HCC chemoresistance still remains unclear. In the present study, circZFR was highly expressed in cisplatin (DDP)-resistant HCC cell lines and could regulate DDP resistance of the HCC cells. Also, circZFR was highly expressed in cancer-associated fibroblast (CAFs) and the exosome of CAFs. In addition, supplementation of CAFs in culture medium could promote DDP resistance of HCC cells. In vivo tumor xenograft experiments showed that knockdown of circZFR inhibited tumor growth and weakened DDP resistance, while CAFs-derived exosomes incubation increased the expression of circZFR, inhibited the STAT3/NF-κB pathway, promoted tumor growth, and enhanced DDP resistance. In general, CAFs-derived exosomes deliver circZFR to HCC cells, inhibit the STAT3/NF-κB pathway, and promote HCC development and chemoresistance. The results provided a new sight for the prevention and treatment of chemoresistance in HCC.