Hsa‑circRNA‑G004213 promotes cisplatin sensitivity by regulating miR‑513b‑5p/PRPF39 in liver cancer

Interplay among extracellular vesicles, cancer stemness and immune regulation in driving hepatocellular carcinoma progression

The intricate interplay among extracellular vesicles, cancer stemness properties, and the immune system significantly impacts hepatocellular carcinoma (HCC) progression, treatment response, and patient prognosis. Extracellular vesicles (EVs), which are membrane-bound structures, play a pivotal role in conveying proteins, lipids, and nucleic acids between cells, thereby serving as essential mediators of intercellular communication. Since a lot of current research focuses on small extracellular vesicles (sEVs), with diameters ranging from 30 nm to 200 nm, this review emphasizes the role of sEVs in the context of interactions between HCC stemness-bearing cells and the immune cells. sEVs offer promising opportunities for the clinical application of innovative diagnostic and prognostic biomarkers in HCC. By specifically targeting sEVs, novel therapeutics aimed at cancer stemness can be developed. Ongoing investigations into the roles of sEVs in cancer stemness and immune regulation in HCC will broaden our understanding and ultimately pave the way for groundbreaking therapeutic interventions.

Circular RNA DNAH14 molecular mechanism in an experimental model of hepatocellular carcinoma treated with Cobalt chloride to mimic the hypoxia-like response of transcatheter arterial chemoembolization

Transcatheter arterial chemoembolization (TACE) is the primary local treatment for patients with unresectable hepatocellular carcinoma (HCC). Numerous studies have demonstrated the pivotal role of circular RNAs (circRNAs) in TACE efficacy. This study aimed to investigate the function of circular RNA DNAH14 (circDNAH14) in TACE for HCC and to elucidate its molecular mechanisms. To simulate hypoxia conditions experienced during TACE, HCC cells were treated with cobalt chloride. The expression levels of circDNAH14, microRNA-508-3p (miR-508-3p), and Prothymosin Alpha (PTMA) were modulated via transfection for knockdown or overexpression. Cell Counting Kit-8 and 5-ethynyl-2'-deoxyuridine assays, flow cytometry, and Transwell assays, along with epithelial-mesenchymal transition (EMT) evaluations, were employed to assess cell proliferation, apoptosis, invasion, migration, and EMT. The results indicated that hypoxia treatment downregulated the expression of circDNAH14 and PTMA while upregulating miR-508-3p. Such treatment suppressed HCC cell proliferation, invasion, migration, and EMT, and induced apoptosis. Knockdown of circDNAH14 or PTMA intensified the suppressive effects of hypoxia on the malignant behaviors of HCC cells. Conversely, upregulation of miR-508-3p or PTMA mitigated the effects of circDNAH14 overexpression and knockdown, respectively. Mechanistically, circDNAH14 was found to competitively bind to miR-508-3p, thereby regulating PTMA expression. In vivo, nude mouse xenograft experiments demonstrated that circDNAH14 knockdown augmented the hypoxia-induced suppression of HCC tumor growth. In conclusion, circDNAH14 mitigates the suppressive effects of hypoxia on HCC, both in vitro and in vivo, by competitively binding to miR-508-3p and regulating PTMA expression.

Combating drug resistance in hepatocellular carcinoma: No awareness today, no action tomorrow

Hepatocellular carcinoma (HCC), the sixth most common cancer worldwide, is associated with a high degree of malignancy and poor prognosis. Patients with early HCC may benefit from surgical resection to remove tumor tissue and a margin of healthy tissue surrounding it. Unfortunately, most patients with HCC are diagnosed at an advanced or distant stage, at which point resection is not feasible. Systemic therapy is now routinely prescribed to patients with advanced HCC; however, drug resistance has become a major obstacle to the treatment of HCC and exploring purported mechanisms promoting drug resistance remains a challenge. Here, we focus on the determinants of drug resistance from the perspective of non-coding RNAs (ncRNAs), liver cancer stem cells (LCSCs), autophagy, epithelial-mesenchymal transition (EMT), exosomes, ferroptosis, and the tumor microenvironment (TME), with the aim to provide new insights into HCC treatment.

CircUSP10 promotes liver cancer progression by regulating miR-211-5p/TCF12/EMT signaling pathway

There is no precise diagnosis or prognosis for liver cancer (LC) using a single biomarker. Circular RNAs (circRNAs) contribute to the pathogenesis of different cancers, but their role in LC is not entirely understood. In this study, circUSP10, an aberrantly expressed circRNA in LC, was screened using the Gene Expression Omnibus database, and its tissue-specific expression was verified using qRT-PCR. In vitro, functional assays and nude mouse tumorigenesis models were used to investigate circUSP10 role in LC. RNA immunoprecipitation and dual-luciferase reporter assays were performed to study the mechanistic relationship between circUSP10, miR-211-5p, and transcription factor 12 (TCF12). We found that circUSP10 expression was upregulated in LC tissues and cells. CircUSP10 expression was linked to tumor size and tumor node metastasis stage and negatively correlated with LC prognosis. In vitro assays confirmed circUSP10-mediated proliferation, migration, and invasion of LC cells and their association with the epithelial-mesenchymal transition (EMT) pathway. Mechanistically, circUSP10 adsorbed miR-211-5p, which regulated TCF12 and promoted tumorigenesis via the EMT signaling pathway. Therefore, our results suggest that circUSP10 may promote LC progression by modulating the miR-211-5p/TCF12/EMT signaling cascade and may serve as a potential biomarker for LC diagnosis and prognosis.

Exosome Cargos as Biomarkers for Diagnosis and Prognosis of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. Due to the insidiousness of HCC onset and the lack of specific early-stage markers, the early diagnosis and treatment of HCC are still unsatisfactory, leading to a poor prognosis. Exosomes are a type of extracellular vesicle containing various components, which play an essential part in the development, progression, and metastasis of HCC. A large number of studies have demonstrated that exosomes could serve as novel biomarkers for the diagnosis of HCC. These diagnostic components mainly include proteins, microRNAs, long noncoding RNAs, and circular RNAs. The exosome biomarkers showed high sensitivity and high specificity in distinguishing HCC from health controls and other liver diseases, such as chronic HBV and liver cirrhosis. The expression of these biomarkers also exhibits correlations with various clinical factors such as tumor size, TMN stage, overall survival, and recurrence rate. In this review, we summarize the function of exosomes in the development of HCC and highlight their application as HCC biomarkers for diagnosis and prognosis prediction.

Circular RNA hsa_circ_0098181 inhibits metastasis in hepatocellular carcinoma by activating the Hippo signaling pathway via interaction with eEF2

INTRODUCTION AND OBJECTIVES

The development of hepatocellular carcinoma (HCC) is a multi-step process that accumulates genetic and epigenetic alterations, including changes in circular RNA (circRNA). This study aimed to understand the alterations in circRNA expression in HCC development and metastasis and to explore the biological functions of circRNA.

MATERIALS AND METHODS

Ten pairs of adjacent chronic hepatitis tissues and HCC tissues from patients without venous metastases, and ten HCC tissues from patients with venous metastases were analyzed using human circRNA microarrays. Differentially expressed circRNAs were then validated by quantitative real-time PCR. In vitro and in vivo assays were performed to assess the roles of the circRNA in HCC progression. RNA pull-down assay, mass spectrometry analysis, and RNA-binding protein immunoprecipitation were conducted to explore the protein partners of the circRNA.

RESULTS

CircRNA microarrays revealed that the expression patterns of circRNAs across the three groups were significantly different. Among these, hsa_circ_0098181 was validated to be lowly expressed and associated with poor prognosis in HCC patients. Ectopic expression of hsa_circ_0098181 delayed HCC metastasis in vitro and in vivo. Mechanistically, hsa_circ_0098181 sequestered eukaryotic translation elongation factor 2 (eEF2) and dissociated eEF2 from filamentous actin (F-actin) to prevent F-actin formation, which blocked activation of the Hippo signaling pathway. In addition, the RNA binding protein Quaking-5 bound directly to hsa_circ_0098181 and induced its biogenesis.

CONCLUSIONS

Our study reveals changes in circRNA expression from chronic hepatitis, primary HCC, to metastatic HCC. Further, the QKI5-hsa_circ_0098181-eEF2-Hippo signaling pathway exerts a regulatory role in HCC.

Recent advances of exosomal circRNAs in cancer and their potential clinical applications

Circular RNA (circRNA) is a type of non-coding RNA that forms a covalently closed, uninterrupted loop. The expression of circRNA differs among cell types and tissues, and various circRNAs are aberrantly expressed in a variety of diseases, including cancer. Aberrantly expressed circRNAs contribute to disease progression by acting as microRNA sponges, functional protein sponges, or novel templates for protein translation. Recent studies have shown that circRNAs are enriched in exosomes. Exosomes are spherical bilayer vesicles released by cells into extracellular spaces that mediate intercellular communication by delivering cargoes. These cargoes include metabolites, proteins, lipids, and RNA molecules. Exosome-mediated cell-cell or cell-microenvironment communications influence the progression of carcinogenesis by regulating cell proliferation, angiogenesis, metastasis as well as immune escape. In this review, we summarize the current knowledge about exosomal circRNAs in cancers and discuss their specific functions in tumorigenesis. Additionally, we discuss the potential value of exosomal circRNAs as diagnostic biomarkers and the potential applications of exosomal circRNA-based cancer therapy.

Exosomal circRNAs in cancer: Implications for therapy resistance and biomarkers

Despite the advances in cancer treatment in recent years, the development of resistance to cancer therapy remains the biggest hurdle towards curative cancer treatments. Therefore, investigating the molecular mechanisms underlying cancer therapy resistance is of paramount clinical importance. Circular RNAs (circRNAs), novel members of the noncoding RNA family, are endogenous biomolecules in eukaryotes characterized by a covalently closed loop structure with multiple biological functions. Significantly, circRNAs are abundant and stable in exosomes and can be packaged, secreted and transferred to targeted tumour cells, thereby modulating diverse hallmarks of cancer behaviours, such as proliferation, migration, and immune escape. Notably, a great number of exosomal circRNAs are abnormally expressed during cancer treatment and can mediate cancer therapy resistance through complex mechanisms; therefore, targeting exosomal circRNAs is a promising therapeutic method to reverse therapy resistance. This review aimed to elucidate the mechanisms underlying exosomal circRNAs controlling the resistance of cancer to common therapies, such as chemotherapy, targeted therapy, immunotherapy and radiotherapy, and we also discussed the therapeutic potential of exosomal circRNAs as clinical biomarkers and novel targets in cancer clinical management. We also discussed the prospects and challenges of targeting exosomal circRNAs as a novel therapeutic strategy for reversing cancer therapy resistance.

Circular RNAs in hepatocellular carcinoma: biogenesis, function, and pathology

Hepatocellular carcinoma (HCC) is one of the most common causes of cancer-related death worldwide. Both genetic and environmental factors through a multitude of underlying molecular mechanisms participate in the pathogenesis of HCC. Recently, numerous studies have shown that circular RNAs (circRNAs), an emerging class of non-coding RNAs characterized by the presence of covalent bonds linking 3' and 5' ends, play an important role in the initiation and progression of cancers, including HCC. In this review, we outline the current status of the field of circRNAs, with an emphasis on the functions and mechanisms of circRNAs in HCC and its microenvironment. We also summarize and discuss recent advances of circRNAs as biomarkers and therapeutic targets. These efforts are anticipated to throw new insights into future perspectives about circRNAs in basic, translational and clinical research, eventually advancing the diagnosis, prevention and treatment of HCC.

Cisplatin in Liver Cancer Therapy

Hepatocellular carcinoma (HCC) is the most common primary liver tumor and is often diagnosed at an unresectable advanced stage. Systemic chemotherapy as well as transarterial chemoembolization (TACE) and hepatic arterial infusion chemotherapy (HAIC) are used to treat advanced HCC. TACE and HAIC have long been the standard of care for patients with unresectable HCC but are limited to the treatment of intrahepatic lesions. Systemic chemotherapy with doxorubicin or chemohormonal therapy with tamoxifen have also been considered, but neither has demonstrated survival benefits. In the treatment of unresectable advanced HCC, cisplatin is administered transhepatic arterially for local treatment. Subsequently, for cisplatin-refractory cases due to drug resistance, a shift to systemic therapy with a different mechanism of action is expected to produce new antitumor effects. Cisplatin is also used for the treatment of liver tumors other than HCC. This review summarizes the action and resistance mechanism of cisplatin and describes the treatment of the major hepatobiliary cancers for which cisplatin is used as an anticancer agent, with a focus on HCC.

Exosomes and circular RNAs: promising partners in hepatocellular carcinoma from bench to bedside

Hepatocellular carcinoma (HCC) is characterized by high morbidity and mortality, and a low 5-year survival rate. Exploring the potential molecular mechanisms, finding diagnostic biomarkers with high sensitivity and specificity, and determining new therapeutic targets for HCC are urgently needed. Circular RNAs (circRNAs) have been found to play a key role in the occurrence and development of HCC, while exosomes play an important role in intercellular communication; thus, the combination of circRNAs and exosomes may have inestimable potential in early diagnosis and curative therapy. Previous studies have shown that exosomes can transfer circRNAs from normal or abnormal cells to surrounding or distant cells; thereafter, circRNAs influence target cells. This review summarizes the recent progress regarding the roles of exosomal circRNAs in the diagnosis, prognosis, occurrence and development and immune checkpoint inhibitor and tyrosine kinase inhibitor resistance of HCC to provide inspiration for further research.

CircRNA OXCT1 promotes the malignant progression and glutamine metabolism of non-small cell lung cancer by absorbing miR-516b-5p and upregulating SLC1A5

Previous study has demonstrated the high expression of circular RNA 3-oxoacid CoA-transferase 1 (circ-OXCT1) in lung adenocarcinoma tumor tissues. However, the role and possible mechanism of circ-OXCT1 in non-small cell lung cancer (NSCLC) progression was unclear.Quantitative real-time PCR (qRT-PCR), western blotting and immunohistochemistry (IHC) staining assay were performed to detect the expression of circ-OXCT1, microRNA-516b-5p (miR-516b-5p), solute carrier family 1 member 5 (SLC1A5) and other indicated protein markers. Cell proliferation was measured by Cell counting kit 8 (CCK8), colony formation and 5-Ethynyl-2'-deoxyuridine (EdU) assays. Flow cytometry was employed to detect the rate of apoptotic cells. Cell migration and invasion were measured using transwell assay. The relative glutamine uptake and α-ketoglutarate (α-KG) production was determined using commercial kits. Interaction between miR-516b-5p and circ-OXCT1 or SLC1A5 was predicted by bioinformatics analysis and confirmed via luciferase reporter and RNA immunoprecipitation (RIP) assays. In vivo assay was implemented to demonstrate the effect of circ-OXCT1 in tumor growth.Circ-OXCT1 and SLC1A5 were upregulated and miR-516b-5p was downregulated in NSCLC tissues and cells. Functional experiments revealed that circ-OXCT1 silencing suppressed cell proliferation, migration and invasion, but promoted cell apoptosis in vitro. Circ-OXCT1 knockdown repressed tumor formation in vivo. Besides, miR-516b-5p was a target of circ-OXCT1, and miR-516b-5p inhibitor could relieve circ-OXCT1 absence-mediated effects in NSCLC cells. SLC1A5 was identified as a target of miR-516b-5p. Circ-OXCT1 promoted SLC1A5 expression by target binding with miR-516b-5p.Circ-OXCT1 facilitated NSCLC progression via miR-516b-5p-dependent regulation of SLC1A5, which provided a possible circRNA-targeted therapy for NSCLC.

Enhanced binding of β-catenin and β-TrCP mediates LMPt's anti-CSCs activity in colorectal cancer

Cancer stem cells (CSCs), a subpopulation of tumor cells with the features of self-renewal, tumor initiation, and insensitivity to common physical and chemical agents, are the key to cancer relapses, metastasis, and resistance. Accessible CSCs inhibitory strategies are primarily based on small molecule drugs, yet toxicity limits their application. Here, we report a liposome loaded with low toxicity and high effectiveness of miriplatin, lipo-miriplatin (LMPt) with high miriplatin loading, and robust stability, exhibiting a superior inhibitory effect on CSCs and non-CSCs. LMPt predominantly inhibits the survival of oxaliplatin-resistant (OXA-resistant) cells composed of CSCs. Furthermore, LMPt directly blocks stemness features of self-renewal, tumor initiation, unlimited proliferation, metastasis, and insensitivity. In mechanistic exploration, RNA sequencing (RNA-seq) revealed that LMPt downregulates the levels of pro-stemness proteins and that the β-catenin-mediated stemness pathway is enriched. Further research shows that either in adherent cells or 3D-spheres, the β-catenin-OCT4/NANOG axis, the vital pathway to maintain stemness, is depressed by LMPt. The consecutive activation of the β-catenin pathway induced by mutant β-catenin (S33Y) and OCT4/NANOG overexpression restores LMPt's anti-CSCs effect, elucidating the key role of the β-catenin-OCT4/NANOG axis. Further studies revealed that the strengthened binding of β-catenin and β-TrCP initiates ubiquitination and degradation of β-catenin induced by LMPt. In addition,the Apc^Min/+transgenicmouse model, in which colon tumors are spontaneously formed, demonstrates LMPt's potent anti-non-CSCs activity in vivo.

The critical role of circular RNAs in drug resistance in gastrointestinal cancers

Nowadays, drug resistance (DR) in gastrointestinal (GI) cancers, as the main reason for cancer-related mortality worldwide, has become a serious problem in the management of patients. Several mechanisms have been proposed for resistance to anticancer drugs, including altered transport and metabolism of drugs, mutation of drug targets, altered DNA repair system, inhibited apoptosis and autophagy, cancer stem cells, tumor heterogeneity, and epithelial-mesenchymal transition. Compelling evidence has revealed that genetic and epigenetic factors are strongly linked to DR. Non-coding RNA (ncRNA) interferences are the most crucial epigenetic alterations explored so far, and among these ncRNAs, circular RNAs (circRNAs) are the most emerging members known to have unique properties. Due to the absence of 5' and 3' ends in these novel RNAs, the two ends are covalently bonded together and are generated from pre-mRNA in a process known as back-splicing, which makes them more stable than other RNAs. As far as the unique structure and function of circRNAs is concerned, they are implicated in proliferation, migration, invasion, angiogenesis, metastasis, and DR. A clear understanding of the molecular mechanisms responsible for circRNAs-mediated DR in the GI cancers will open a new window to the management of GI cancers. Hence, in the present review, we will describe briefly the biogenesis, multiple features, and different biological functions of circRNAs. Then, we will summarize current mechanisms of DR, and finally, discuss molecular mechanisms through which circRNAs regulate DR development in esophageal cancer, pancreatic cancer, gastric cancer, colorectal cancer, and hepatocellular carcinoma.

Exosomal circular RNAs: A chief culprit in cancer chemotherapy resistance

Chemotherapy is one of the primary treatments for malignant tumors. However, the acquired drug resistance hinders clinical efficacy and leads to treatment failure in most patients. Exosomes are cell-derived vesicles with a diameter of 30-150 nm carrying and delivering substances such as DNAs, RNAs, lipids, and proteins for cellular communication in tumor development. Circular RNAs (circRNAs) present covalently closed-loop RNA structures, which regulate tumor cell proliferation, apoptosis, and metastasis by controlling different genes and signaling pathways. CircRNAs are abundant and stably expressed in exosomes. Recent studies have shown that they play critical roles in chemotherapy resistance in various cancers. In this review, we summarized the origin of exosomes and discussed the regulation mechanism of exosomal circRNAs in cancer drug resistance.

Non-coding RNA in cancer drug resistance: Underlying mechanisms and clinical applications

Cancer is one of the most frequently diagnosed malignant diseases worldwide, posing a serious, long-term threat to patients’ health and life. Systemic chemotherapy remains the first-line therapeutic approach for recurrent or metastatic cancer patients after surgery, with the potential to effectively extend patient survival. However, the development of drug resistance seriously limits the clinical efficiency of chemotherapy and ultimately results in treatment failure and patient death. A large number of studies have shown that non-coding RNAs (ncRNAs), particularly microRNAs, long non-coding RNAs, and circular RNAs, are widely involved in the regulation of cancer drug resistance. Their dysregulation contributes to the development of cancer drug resistance by modulating the expression of specific target genes involved in cellular apoptosis, autophagy, drug efflux, epithelial-to-mesenchymal transition (EMT), and cancer stem cells (CSCs). Moreover, some ncRNAs also possess great potential as efficient, specific biomarkers in diagnosis and prognosis as well as therapeutic targets in cancer patients. In this review, we summarize the recent findings on the emerging role and underlying mechanisms of ncRNAs involved in cancer drug resistance and focus on their clinical applications as biomarkers and therapeutic targets in cancer treatment. This information will be of great benefit to early diagnosis and prognostic assessments of cancer as well as the development of ncRNA-based therapeutic strategies for cancer patients.

Roles of small extracellular vesicles in the development, diagnosis and possible treatment strategies for hepatocellular carcinoma (Review)

Hepatocellular carcinoma (HCC) is the most common malignancy of hepatocytes accounting for 75-85% of primary hepatic carcinoma cases. Small extracellular vesicles (sEVs), previously known as exosomes with a diameter of 30-200 nm, can transport a variety of biological molecules between cells, and have been proposed to function in physiological and pathological processes. Recent studies have indicated that the cargos of sEVs are implicated in intercellular crosstalk among HCC cells, paratumor cells and the tumor microenvironment. sEV-encapsulated substances (including DNA, RNA, proteins and lipids) regulate signal transduction pathways in recipient cells and contribute to cancer initiation and progression in HCC. In addition, the differential expression of sEV cargos between patients facilitates the potential utility of sEVs in the diagnosis and prognosis of patients with HCC. Furthermore, the intrinsic properties of low immunogenicity and high stability render sEVs ideal vehicles for targeted drug delivery in the treatment of HCC. The present review article summarizes the carcinogenic and anti-neoplastic capacities of sEVs and discusses the potential and prospective diagnostic and therapeutic applications of sEVs in HCC.

Exosomal Non-Coding RNAs: New Insights into the Biology of Hepatocellular Carcinoma

Exosomes, extracellular vesicles with a diameter of 40 to 160 nm, are among the smallest extracellular vesicles released by cells. They deliver different cargoes, including proteins, DNAs, and RNAs, and facilitate communication between cells to coordinate a variety of physiological and pathological functions. Hepatocellular carcinoma (HCC) is the sixth common malignant tumor and the fourth leading cause of cancer-related death worldwide. Its molecular mechanism remains largely unknown, and there is a lack of reliable and noninvasive biomarkers for early diagnosis and prognosis prediction. Mounting evidence has shown that exosomes carry a variety of ncRNAs, such as long non-coding RNAs (lncRNAs), microRNAs (miRNAs), and circular RNAs (circRNAs), which play critical roles in the occurrence and progression of HCC. In this review, we summarize the recent findings of exosomal miRNAs, lncRNAs, and circRNAs in HCC from their impact on the development of HCC to their potential applications in the diagnosis and treatment of HCC.

Overexpression of circ PTK2 suppresses the progression of nonalcoholic fatty liver disease via the miR-200c/SIK2/PI3K/Akt axis

Excessive hepatic lipid accumulation is involved in the pathogenesis of nonalcoholic fatty liver disease (NAFLD). A previous study showed that the circular RNA (circRNA) PTK2 was significantly downregulated in NAFLD mice. However, the detailed function of circ PTK2 in NAFLD remains unclear. A high-fat diet (HFD) was used to establish a mouse model of NAFLD, and free fatty acid (FFA) treatment was used to establish an in vitro model of NAFLD. Oil red O staining was used to evaluate lipid accumulation. The pathological changes in mice were observed by HE staining. Western blotting and RT-qPCR were applied to assess protein and mRNA levels, respectively. A dual luciferase reporter assay and RIP were used to explore the relationship among circ PTK2, miR-200c and SIK2. Circ PTK2 and SIK2 were downregulated and miR-200c was upregulated in NAFLD. Upregulation of circ PTK2 reversed lipid accumulation in FFA-treated HepG2 cells. Moreover, circ PTK2 bound to miR-200c, and SIK2 was identified as the direct target of miR-200c. Moreover, the miR-200c inhibitor-induced decrease in lipid accumulation was reversed by SIK2 knockdown. Furthermore, the impact of circ PTK2 overexpression on PI3K/Akt signaling was partially reversed by SIK2 silencing. Circ PTK2 overexpression alleviates NAFLD development via the miR-200c/SIK2/PI3K/Akt axis. Thus, our work might provide new methods for NAFLD treatment.

Cytotoxic capability and the associated proteomic profile of cell-free coelomic fluid extracts from the edible sea cucumber Holothuria tubulosa on HepG2 liver cancer cells

Hepatocellular carcinoma (HCC) is an aggressive cancer histotype and one of the most common types of cancer worldwide. The identification of compounds that might intervene to restrain neoplastic cell growth appears imperative due to its elevated overall mortality. The marine environment represents a reservoir rich in bioactive compounds in terms of primary and secondary metabolites produced by aquatic animals, mainly invertebrates. In the present study, we determined whether the water-soluble cell-free extract of the coelomic fluid (CFE) of the edible sea cucumber Holothuria tubulosa could play an anti-HCC role in vitro by analyzing the viability and locomotory behavior, cell cycle distribution, apoptosis and autophagy modulation, mitochondrial function and cell redox state of HepG2 HCC cells. We showed that CFE causes an early block in the cell cycle at the G₂/M phase, which is coupled to oxidative stress promotion, autophagosome depletion and mitochondrial dysfunction ultimately leading to apoptotic death. We also performed a proteomic analysis of CFE identifying a number of proteins that are seemingly responsible for anti-cancer effects. In conclusion, H. tubulosa's CFE merits further investigation to develop novel promising anti-HCC prevention and/or treatment agents and also beneficial supplements for formulation of functional foods and food packaging material.

Circular RNAs in hepatocellular carcinoma: Recent advances

Circular RNAs (circRNAs) have covalently closed loop structures at both ends, exhibiting characteristics dissimilar to those of linear RNAs. Emerging evidence suggests that aberrantly expressed circRNAs play crucial roles in hepatocellular carcinoma (HCC) by affecting the proliferation, apoptosis and invasive capacity of HCC cells. Certain circRNAs may be used as biomarkers to diagnose and predict the prognosis of HCC. Therefore, circRNAs are expected to become novel biomarkers and therapeutic targets for HCC. Herein, we briefly review the characteristics and biological functions of circRNAs, focusing on their roles in HCC to provide new insights for the early diagnosis and targeted therapy of HCC.

Advances in the Study of CircRNAs in Tumor Drug Resistance

Recent studies have revealed that circRNAs can affect tumor DNA damage and repair, apoptosis, proliferation, and invasion and influence the transport of intratumor substances by acting as miRNA sponges and transcriptional regulators and binding to proteins in a variety of ways. However, research on the role of circRNAs in cancer radiotherapy and chemoresistance is still in its early stages. Chemotherapy is a common approach to oncology treatment, but the development of tumor resistance limits the overall clinical efficacy of chemotherapy for cancer patients. The current study suggests that circRNAs have a facilitative or inhibitory effect on the development of resistance to conventional chemotherapy in a variety of tumors, suggesting that circRNAs may serve as a new direction for the study of antitumor drug resistance. In this review, we will briefly discuss the biological features of circRNAs and summarize the recent progression of the involvement of circRNAs in the development and pathogenesis of cancer chemoresistance.

The Potential Roles of Exosomal Non-Coding RNAs in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the sixth highest-incidence cancer and the 4th most deadly cancer all over the world, with a high fatality and low diagnostic rate. Nowadays, Excessive alcohol consumption, type-2 diabetes, smoking and obesity have become some primary risk factors of HCC. As intercellular messenger transporting information cargoes between cells, exosomes are a type of extracellular vesicles (EVs) released by most types of cells including tumor cells and non-tumor cells and play a pivotal role in establishing an HCC microenvironment. Exosomes, and more generally EVs, contain different molecules, including messenger RNAs (mRNAs), non-coding RNAs (ncRNAs), proteins, lipids and transcription factors. The three main ncRNAs in exosomes are microRNAs (miRNAs), long non-coding RNAs (lncRNAs), circular RNAs (circRNAs). NcRNAs, identified as essential components, are selectively sorted into exosomes and exosomal ncRNAs show great potential in regulating tumor development, including proliferation, invasion, angiogenesis, metastasis, immune escape and drug resistance. Here, we chiefly review the formation and uptake of exosomes, classification of exosomal ncRNAs and current research on the roles of exosomal ncRNAs in HCC progression. We also explored their clinical applications as new diagnostic biomarkers and therapeutic avenues in HCC.

Construction of miRNA-mRNA regulatory network and analysis of hub genes in oral squamous cell carcinoma

BACKGROUND

Oral squamous cell carcinoma (OSCC) severely affects the quality of life and the 5-year survival rate is low. Exploring the potential miRNA-mRNA regulatory network and analyzing hub genes and clinical data can provide a theoretical basis for further elucidating the pathogenesis of OSCC.

METHODS

The miRNA expression datasets of GSE113956 and GSE124566 and mRNA expression datasets of GSE31056, GSE37991 and GSE13601 were obtained from the Gene Expression Omnibus databases. The differentially expressed miRNAs (DEMs) and mRNAs (DEGs) were screened using GEO2R. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed by DAVID database. The PPI network was established through STRING database and the hub genes were preliminarily screened out by Cytoscape software. After identifying the hub genes in the TCGA database, we predicted the potential DEM transcription factors, constructed a miRNA-mRNA regulatory network, and analyzed the relationship between the hub genes and clinical data.

RESULTS

A total of 28 DEMs and 764 DEGs were screened out, which were composed of 285 up-regulated genes and 479 down-regulated genes. Enrichment analysis showed that up-regulation of DEGs were mainly enriched in extracellular matrix organization and cancer-related pathway, while down-regulation of DEGs were mainly enriched in muscular system process and adrenaline signal transduction. After preliminary screening by PPI network and identification in TCGA, the up-regulated FN1, COL1A1, COL1A2, AURKA, CCNB1, CCNA2, SPP1, CDC6, and down-regulated ACTN2, TTN, IGF1, CAV3, MYL2, DMD, LDB3, CSRP3, ACTA1, PPARG were identified as hub genes. The miRNA-mRNA regulation network showed that hsa-miR-513b was the DEM with the most regulation, and COL1A1 was the DEG with the most regulation. In addition, CDC6, AURKA, CCNB1 and CCNA2 were related to overall survival and tumor differentiation.

CONCLUSIONS

The regulatory relationship of hsa-miR-513b/ CDC6, CCNB1, CCNA2 and the regulatory relationship of hsa-miR-342-5p /AURKA were not only verified in the miRNA-mRNA regulatory network but also related to overall survival and tumor differentiation. These results indicated that they participated in the cellular regulatory process, and provided a molecular mechanism model for the study of pathogenesis.

N6-Methyladenosine-regulated LINC00675 Suppress the Proliferation, Migration and Invasion of Breast Cancer cells via Inhibiting miR-513b-5p

Breast cancer (BC) is the most common cancer among women. LINC00675 and miR-513b-5p has been reported to be abnormally expressed in multiple types of cancers and modulate malignant phenotypes of cancer cells. However, to date, the functional role and underlying regulatory mechanism of LINC00675 and miR-513b-5p in BC remains largely unknown. Here, we found that LINC00675 was significantly downregulated in BC tissues and cell lines. Decrease of LINC00675 expression associated with higher tumor grade, lymphovascular invasion and shorter survival in BC patients. Functional experiments demonstrated that overexpression of LINC00675 suppressed BC cell proliferation, migration and invasion, whereas depletion of LINC00675 exerted opposite effects. Mechanistically, LINC00675 functioned as a competing endogenous RNA (ceRNA) to interact with miR-513b-5p and suppress its expression. Moreover, METTL3 increased the m⁶A methylation of LINC00675, which enhanced the association between LINC00675 and miR-513b-5p. Collectively, the central findings of our study suggest that LINC00675 represses BC progression through the inhibition of miR-513b-5p in a m⁶A-dependent manner.

Circ_PIP5K1A regulates cisplatin resistance and malignant progression in non-small cell lung cancer cells and xenograft murine model via depending on miR-493-5p/ROCK1 axis

Background

Chemoresistance limits the therapeutic effect of cisplatin (DDP) on non-small cell lung cancer (NSCLC). Circular RNAs (circRNAs) function as important regulators in chemoresistance. This study aimed to explore the regulation of circRNA Phosphatidylinositol-4-Phosphate 5-Kinase Type 1 Alpha (circ_PIP5K1A) in DDP resistance.

Methods

The expression analysis of circ_PIP5K1A, micoRNA-493-5p (miR-493-5p) and Rho Associated Coiled-Coil Containing Protein Kinase 1 (ROCK1) was conducted through reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Cell sensitivity was determined using 3-(4,5-dimethylthiazol-2-y1)-2,5-diphenyl tetrazolium bromide (MTT) assay. Cell proliferation and cell viability were evaluated by colony formation assay and MTT assay, respectively. Cell cycle and apoptosis detection was performed via flow cytometry. Cell motility was examined by transwell migration or invasion assay. Dual-luciferase reporter assay was applied to confirm the target binding. ROCK1 protein level was assayed via Western blot. In vivo assay was carried out using xenograft model in mice.

Results

Circ_PIP5K1A level was abnormally increased in DDP-resistant NSCLC tissues and cells. Silencing circ_PIP5K1A reduced DDP resistance, proliferation, cell cycle progression and cell motility in DDP-resistant NSCLC cells. Circ_PIP5K1A directly interacted with miR-493-5p in NSCLC cells. The function of circ_PIP5K1A was dependent on the negative regulation of miR-493-5p. MiR-493-5p directly targeted ROCK1 and circ_PIP5K1A regulated the ROCK1 level via acting as a sponge of miR-493-5p. Overexpression of miR-493-5p inhibited chemoresistance and cancer progression by downregulating ROCK1 expression in DDP-resistant NSCLC cells. Circ_PIP5K1A regulated DDP sensitivity in vivo via the miR-493-5p/ROCK1 axis.

Conclusion

These findings suggested that circ_PIP5K1A upregulated the ROCK1 expression to promote DDP resistance and cancer progression in NSCLC by sponging miR-493-5p.

MiR-513b-5p represses autophagy during the malignant progression of hepatocellular carcinoma by targeting PIK3R3

Hepatocellular carcinoma (HCC) serves as a prevailing global malignancy with severe mortality and extremely unsatisfactory prognosis, in which autophagy is a fundamental process in liver cancer pathogenesis, but the mechanisms are poorly understood. MicroRNAs (miRNAs) serve as a type of well-recognized non-coding regulators and contribute to the modulation of liver cancer development, from the aspects of diagnosis, progression, and therapy. Here, we aimed to investigate the function of hsa_microRNA-513b-5p (miR-513b-5p) in regulating autophagy during HCC progression. Specifically, our data showed that miR-513b-5p mimic reduced the LC3-II and beclin1 expression but enhanced p62 expression in HCC cells. MiR-513b-5p repressed liver cancer cell proliferation, migration/invasion, and induced apoptosis in vitro. Crucially, miR-513b-5p attenuated tumor growth of liver cancer cells in vivo. In the mechanical investigation, we identified that PIK3R3 mRNA 3′UTR was targeted by miR-513b-5p and miR-513b-5p suppressed PIK3R3 expression. PIK3R3 overexpression partly reversed miR-513b-5p-mediated autophagy, proliferation, and apoptosis of liver cancer cells. Consequently, we concluded that miR-513b-5p repressed autophagy during the malignant progression of HCC by targeting PIK3R3. MiR-513b-5p may be applied as a therapeutic target for HCC.