CircFGGY Inhibits Cell Growth, Invasion and Epithelial-Mesenchymal Transition of Hepatocellular Carcinoma via Regulating the miR-545-3p/Smad7 Axis

Unraveling the oncogenic role of LINC00504 and its interaction with miR-545-3p and ARIHI in hepatocellular carcinoma: novel insights for molecular therapy

OBJECTIVES

Hepatocellular carcinoma (HCC) is a serious global health threat associated with high morbidity and mortality. The importance of long non-coding RNAs (lncRNAs) in tumor progression is growing. The aim of this study was to explore the expression, functional properties and molecular mechanisms of LINC00504 in HCC.

MATERIALS AND METHODS

Tumor tissue samples from HCC patients were collected to analyze the expression of LINC00504, miR-545-3p, and ARIH1 mRNA using RT-qPCR, and compared with various HCC cell lines (PLC/PRF/5, SNU-182, Hep3B, HuH-7) and a human normal liver epithelial cell line (THLE-2). Cell proliferation, apoptosis, and invasion were assessed using transfection vectors, CCK8 assay, flow cytometry, and Transwell. Interactions among LINC00504, miR-545-3p, and ARIH1 were confirmed through database predictions and luciferase reporter gene assays.

RESULTS

LINC00504 was underexpressed in HCC tissues and cell lines. Upregulation of LINC00504 inhibited cell proliferation, induced apoptosis, increased Bax and Caspase-3, decreased Bcl-2 mRNA, and suppressed invasion. miR-545-3p was overexpressed in HCC cells and was negatively regulated by LINC00504. Overexpression of miR-545-3p counteracted the effects of LINC00504 upregulation. ARIH1 was underexpressed in HCC tissues and had a negative correlation with miR-545-3p. miR-545-3p negatively regulated ARIH1 expression, and ARIH1 overexpression overturned the promotional effects of miR-545-3p on HCC cells.

CONCLUSION

This study uncovers the significant tumor-suppressing role of LINC00504 in HCC, potentially through a mechanism involving the targeting of miR-545-3p, which in turn inhibits the ARIH1. These findings offer new potential targets for HCC molecular treatment.

Identification and Validation of the Hsa_circ_0001726/miR-140-3p/KRAS Axis in Hepatocellular Carcinoma Based on Microarray Analyses and Experiments

Background and Aims

Hepatocellular carcinoma (HCC) is one of the most fatal malignancies. Epigenetic mechanisms have revealed that noncoding RNAs, such as microRNAs (miRNAs) and circular RNAs (circRNAs), are involved in HCC progression. This study aimed to construct a circRNA-miRNA-mRNA network in HCC and validate one axis within the network.

Methods

HCC-related transcriptome data were obtained from the Gene Expression Omnibus, and HCC-related genes were sourced from GeneCards to identify differentially expressed circRNAs and miRNAs. The targeting relationships between circRNA-miRNA and miRNA-mRNA interactions were predicted. The involvement of the hsa_circ_0001726/miR-140-3p/KRAS axis in HCC was evaluated through cellular experiments and survival analyses.

Results

We identified six differentially expressed circRNAs in HCC, which were linked to 13 miRNAs and 88 mRNAs. A network containing 34 circRNA-miRNA pairs and 194 miRNA-mRNA pairs was constructed. Cell proliferation and migration assays confirmed the role of hsa_circ_0001726 in promoting HCC progression, possibly through the miR-140-3p/KRAS axis. Survival analysis verified that hsa_circ_0001726 was a prognostic factor for overall survival in patients with HCC. The hsa_circ_0001726/miR-140-3p/KRAS axis also mediates lenvatinib resistance in HCC cells.

Conclusions

The HCC circRNA/miRNA/mRNA network provides new insights into the post-transcriptional regulatory mechanism of HCC. The hsa_circ_0001726/miR-140-3p/KRAS axis is involved in HCC progression and lenvatinib resistance.

Current and future perspectives on the regulation and functions of miR-545 in cancer development

Micro ribonucleic acids (miRNAs) are a highly conserved class of single-stranded non-coding RNAs. Within the miR-545/374a cluster, miR-545 resides in the intron of the long non-coding RNA (lncRNA) FTX on Xq13.2. The precursor form, pre-miR-545, is cleaved to generate two mature miRNAs, miR-545-3p and miR-545-5p. Remarkably, these two miRNAs exhibit distinct aberrant expression patterns in different cancers; however, their expression in colorectal cancer remains controversial. Notably, miR-545-3p is affected by 15 circular RNAs (circRNAs) and 10 long non-coding RNAs (lncRNAs), and it targets 27 protein-coding genes (PCGs) that participate in the regulation of four signaling pathways. In contrast, miR-545-5p is regulated by one circRNA and five lncRNAs, it targets six PCGs and contributes to the regulation of one signaling pathway. Both miR-545-3p and miR-545-5p affect crucial cellular behaviors, including cell cycle, proliferation, apoptosis, epithelial-mesenchymal transition, invasion, and migration. Although low miR-545-3p expression is associated with poor prognosis in three cancer types, studies on miR-545-5p are yet to be reported. miR-545-3p operates within a diverse range of regulatory networks, thereby augmenting the efficacy of cancer chemotherapy, radiotherapy, and immunotherapy. Conversely, miR-545-5p enhances immunotherapy efficacy by inhibiting T-cell immunoglobulin and mucin-domain containing-3 (TIM-3) expression. In summary, miR-545 holds immense potential as a cancer biomarker and therapeutic target. The aberrant expression and regulatory mechanisms of miR-545 in cancer warrant further investigation.

CircRNAs: Pivotal modulators of TGF-β signalling in cancer pathogenesis

The intricate molecular landscape of cancer pathogenesis continues to captivate researchers worldwide, with Circular RNAs (circRNAs) emerging as pivotal players in the dynamic regulation of biological functions. The study investigates the elusive link between circRNAs and the Transforming Growth Factor-β (TGF-β) signalling pathway, exploring their collective influence on cancer progression and metastasis. Our comprehensive investigation begins by profiling circRNA expression patterns in diverse cancer types, revealing a repertoire of circRNAs intricately linked to the TGF-β pathway. Through integrated bioinformatics analyses and functional experiments, we elucidate the specific circRNA-mRNA interactions that modulate TGF-β signalling, unveiling the regulatory controls governing this crucial pathway. Furthermore, we provide compelling evidence of the impact of circRNA-mediated TGF-β modulation on key cellular processes, including epithelial-mesenchymal transition (EMT), migration, and cell proliferation. In addition to their mechanistic roles, circRNAs have shown promise as diagnostic and prognostic biomarkers, as well as potential molecular targets for cancer therapy. Their ability to modulate critical pathways, such as the TGF-β signalling axis, underscores their significance in cancer biology and clinical applications. The intricate interplay between circRNAs and TGF-β is dissected, uncovering novel regulatory circuits that contribute to the complexity of cancer biology. This review unravels a previously unexplored dimension of carcinogenesis, emphasizing the crucial role of circRNAs in shaping the TGF-β signalling landscape.

The pivotal role of EMT-related noncoding RNAs regulatory axes in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) remains a major health problem worldwide, being the leading cause of cancer-related deaths, with limited treatment options, especially in its advanced stages. Tumor resistance is closely associated with the activation of the EMT phenomenon and its reversal, being modulated by different molecules, including noncoding RNAs (ncRNAs). Noncoding RNAs have the potential to function as both tumor suppressors and oncogenic molecules, controlling the malignant potential of HCC cells. Basically, these molecules circulate in the tumor microenvironment, encapsulated in exosomes. Their impact on cell biology is more significant than originally expected, which makes related research rather complex. The temporal and spatial expression patterns, precise roles and mechanisms of specific ncRNAs encapsulated in exosomes remain primarily unknown in different stages of the disease. This review aims to highlight the recent advances in ncRNAs related to EMT and classifies the described mechanism as direct and indirect, for a better summarization. Moreover, we provide an overview of current research on the role of ncRNAs in several drug resistance-related pathways, including the emergence of resistance to sorafenib, doxorubicin, cisplatin and paclitaxel therapy. Nevertheless, we comprehensively discuss the underlying regulatory mechanisms of exosomal ncRNAs in EMT-HCC via intercellular communication pathways.

SMAD Proteins in TGF-β Signalling Pathway in Cancer: Regulatory Mechanisms and Clinical Applications

Suppressor of mother against decapentaplegic (SMAD) family proteins are central to one of the most versatile cytokine signalling pathways in metazoan biology, the transforming growth factor-β (TGF-β) pathway. The TGF-β pathway is widely known for its dual role in cancer progression as both an inhibitor of tumour cell growth and an inducer of tumour metastasis. This is mainly mediated through SMAD proteins and their cofactors or regulators. SMAD proteins act as transcription factors, regulating the transcription of a wide range of genes, and their rich post-translational modifications are influenced by a variety of regulators and cofactors. The complex role, mechanisms, and important functions of SMAD proteins in tumours are the hot topics in current oncology research. In this paper, we summarize the recent progress on the effects and mechanisms of SMAD proteins on tumour development, diagnosis, treatment and prognosis, and provide clues for subsequent research on SMAD proteins in tumours.

Review of novel functions and implications of circular RNAs in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most frequent malignancies, with high incidence and mortality. As the majority of HCC patients are diagnosed at an advanced stage and die of recurrence and metastasis, its pathology and new biomarkers are needed. Circular RNAs (circRNAs) are a large subclass of long non-coding RNAs (lncRNAs) with covalently closed loop structures and abundant, conserved, stable, tissue-specific expression in mammalian cells. CircRNAs exert multiple functions in HCC initiation, growth and progression, serving as promising biomarkers for diagnosis, prognosis and therapeutic targets for this disease. This review briefly describes the biogenesis and biological functions of circRNAs and elucidates the roles of circRNAs in the development and progression of HCC, especially regarding epithelial-mesenchymal transition (EMT), drug resistance and interactions with epigenetic modifications. In addition, this review highlights the implications of circRNAs as potential biomarkers and therapeutic targets for HCC. We hope to provide novel insight into the roles of circRNAs in HCC.