SPATS2, negatively regulated by miR-145-5p, promotes hepatocellular carcinoma progression through regulating cell cycle

Liposome-lentivirus for miRNA therapy with molecular mechanism study

BACKGROUND

Cancer stem cells (CSCs) play a vital role in the occurrence, maintenance, and recurrence of solid tumors. Although, miR-145-5p can inhibit CSCs survival, poor understanding of the underlying mechanisms hamperes further therapeutic optimization for patients. Lentivirus with remarkable transduction efficiency is the most commonly used RNA carrier in research, but has shown limited tumor-targeting capability.

METHODS

We have applied liposome to decorate lentivirus surface thereby yielding liposome-lentivirus hybrid-based carriers, termed miR-145-5p-lentivirus nanoliposome (MRL145), and systematically analyzed their potential therapeutic effects on liver CSCs (LCSCs).

RESULTS

MRL145 exhibited high delivery efficiency and potent anti-tumor efficacy under in vitro and in vivo. Mechanistically, the overexpressed miR-145-5p can significantly suppress the self-renewal, migration, and invasion abilities of LCSCs by targeting Collagen Type IV Alpha 3 Chain (COL4A3). Importantly, COL4A3 can promote phosphorylating GSK-3β at ser 9 (p-GSK-3β S9) to inactivate GSK3β, and facilitate translocation of β-catenin into the nucleus to activate the Wnt/β-catenin pathway, thereby promoting self-renewal, migration, and invasion of LCSCs. Interestingly, COL4A3 could attenuate the cellular autophagy through modulating GSK3β/Gli3/VMP1 axis to promote self-renewal, migration, and invasion of LCSCs.

CONCLUSIONS

These findings provide new insights in mode of action of miR-145-5p in LCSCs therapy and indicates that liposome-virus hybrid carriers hold great promise in miRNA delivery.

The Value of Chemokine and Chemokine Receptors in Diagnosis, Prognosis, and Immunotherapy of Hepatocellular Carcinoma

Background

Chemokines and chemokine receptors (CCRs) are involved in a variety of anti-tumour and pro-tumour immune processes in vivo, such as angiogenesis, metastasis, proliferation and invasiveness, and influence patient prognosis and response to therapy.

Methods

CCRs differentially expressed in HCC and associated with prognosis were extracted from TCGA and GEO databases, and the obtained CCRs were then used to construct signature genes, and the signature gene were selected for expression validation as well as functional experiments to explore the role of CCRs in the treatment and prognosis of HCC.

Results

We constructed a prognostic model including five CCRs (CCL20, CCL23, CCR3, CCR10, and CXCR3) and validated the expression of signature genes. The model's risk score is an independent prognostic factor for HCC. We have also developed prognostic model nomograms for clinical use. In addition, we validated that CCR3 expression is associated with poor prognosis in HCC, and the proliferation and migration ability of HCC cells was significantly inhibited after interfering with the expression of CCR3 in MHCC-LM3. We also looked at differences in pathway enrichment, immune infiltration and immune checkpoints. Finally, we found that risk scores were also correlated with drug sensitivity, the high-risk group had a better sensitivity to sorafenib.

Conclusion

The CCRs-related gene signature may better assess HCC prognosis and response to immunotherapy and tyrosine kinase inhibitors such as sorafenib in HCC, providing prospective solutions for diagnosis and treatment.

LncRNA MEG3 Inhibits Tumor Progression by Modulating Macrophage Phenotypic Polarization via miR-145-5p/DAB2 Axis in Hepatocellular Carcinoma

Background

Hepatocellular carcinoma (HCC) is the predominant histological type of primary liver cancer, which ranks sixth among the most common human tumors. Tumor-associated macrophages (TAMs) are an important component of tumor microenvironment (TME) and the M2 macrophage polarization substantially contributes to tumor growth and metastasis. Long non-coding RNA (lncRNA) MEG3 was reported to restrain HCC development. However, whether MEG3 regulates macrophage phenotypic polarization in HCC remains unclear.

Methods

Bone marrow derived macrophages (BMDMs) were treated with LPS/IFNγ and IL4/IL13 to induce the M1 and M2 macrophage polarization, respectively. M2-polarized BMDMs were simultaneously transfected with adenovirus vector overexpressing MEG3 (Adv-MEG3). Subsequently, M2-polarized BMDMs were cultured for 24 h with serum-free medium, the supernatants of which were harvested as conditioned medium (CM). HCC cell line Huh7 was cultured with CM for 24 h. F4/80⁺CD68⁺ and F4/80⁺CD206⁺ cell percentages in M1-and M2-polarized BMDMs were calculated using flow cytometry. Huh7 cell migration, invasion and angiogenesis were determined via Transwell assay and tube formation experiment. Nude mice were implanted with Huh7 cells and Adv-MEG3-transfected M2-polarizd BMDMs, and tumor growth and M2 macrophage polarization markers were assessed. The binding between miR-145-5p and MEG3 or disabled-2 (DAB2) was verified by luciferase reporter assay.

Results

MEG3 presented lower expression in HCC tissues than in normal controls, and low expression of MEG3 was correlated to poorer prognosis of HCC patients. MEG3 expression was enhanced during LPS/IFNγ-induced M1 polarization, but was reduced during IL4/IL13-induced M2 polarization. MEG3 overexpression inhibited the expression of M2 polarization markers in both M2-polarized BMDMs and mice. Mechanically, MEG3 bound with miR-145-5p to regulate DAB2 expression. Overexpressing MEG3 suppressed M2 polarization-induced HCC cell metastasis and angiogenesis by upregulating DAB2 and inhibited in vivo tumor growth.

Conclusion

LncRNA MEG3 curbs HCC development by repressing M2 macrophage polarization via miR-145-5p/DAB2 axis.

Bioinformatics Analysis Identifies ASCL1 as the Key Transcription Factor in Hepatocellular Carcinoma Progression

Methods

Differentially transcription factors (DETFs) were identified from differentially expressed genes (DEGs) in GSE62232 and transcription factors. Then, they were analyzed by regulatory networks, prognostic risk model, and overall survival analyses to identify the key DETF. Combined with the regulatory networks and binding site analysis, the target mRNA of key DETF was determined, and its prognostic value in HCC was evaluated by survival, clinical characteristics analyses, and experiments. Finally, the expressions and functions of the key DETF on the DEmRNAs were investigated in HCC cells.

Results

Through multiple bioinformatics analyses, ASCL1 was identified as the key DETF, and SLC6A13 was predicted to be its target mRNA with the common binding site of CCAGCAACTGGCC, both downregulated in HCC. In survival analysis, high SLC6A13 was related to better HCC prognosis, and SLC6A13 was differentially expressed in HCC patients with clinical characteristics. Furthermore, cell experiments showed the mRNA expressions of ASCL1 and SLC6A13 were both reduced in HCC, and their overexpressions suppressed the growth, invasion, and migration of HCC cells. Besides, over-ASCL1 could upregulate SLC6A13 expression in HCC cells.

Conclusion

This study identifies two suppressor genes in HCC progression, ASCL1 and SLC6A13, and the key transcription factor ASCL1 suppresses HCC progression by targeting SLC6A13 mRNA. They are both potential treatment targets and prognostic biomarkers for HCC patients, which provides new clues for HCC research.

SPATS2 is correlated with cell cycle progression and immune cells infiltration in hepatocellular carcinoma

The spermatogenesis associated serine rich 2 (SPATS2) is a member of RNA-binding protein in which the abnormal expression is linked with carcinogenesis in serval types of cancer. However, there is no systematic study on the differential expression, prognostic significance, epigenetic regulation, immune infiltration of SPATS2 in hepatocellular carcinoma (HCC). In the present study, we investigated the expression, prognosis, epigenetic regulation, and immune cell infiltration of SPATS2 in HCC. We found that the elevated expression of SPATS2 was unfavorably associated with the clinical pathological stage and prognosis. Functional enrichment analysis revealed that SPATS2 is associated with cell cycle, apoptosis and cancer cell metastasis processes in HCC. Our results confirmed that knockdown of SPATS2 will affect cell cycle, apoptosis and invasion of HCC cell lines. Moreover, the expression of SPATS2 is upregulated by epigenetic regulation, including DNA methylation, m6A and histone modification in HCC. In addition, SPATS2 expression was positively correlated with immune cell infiltration or expression of immune related gene markers in HCC. Taken together, our data demonstrated that SPATS2 is associated with progression and immune infiltration, and could serve as a prognostic biomarker for HCC. In conclusion, these results highlight the potential of SPATS2 to be used as a therapeutic target for HCC.

Long noncoding RNA MAPKAPK5-AS1 promotes metastasis through regulation miR-376b-5p/ECT2 axis in hepatocellular carcinoma

BACKGROUND AND AIMS

Hepatocellular carcinoma (HCC) is one of the most common diseases threatening human health worldwide. However, the molecular mechanisms of HCC are still unclear. Here, we identified a differentially expressed lncRNA called MAPKAPK5-AS1(abbreviation: MK5-AS1) and elucidated its role and molecular mechanism in the development of HCC.

METHODS

Real-time PCR (RT-PCR) was used to verify the expression of MK5-AS1 in hepatocarcinoma cell lines and tumor tissues of HCC patients. The biological functions of MK5-AS1 in HCC cells was assessed both in vitro and in vivo assays. The Lncbase, miRDB and TargetScan databases were used to predict the lncRNA-miRNA-mRNA interactions. RNA immunoprecipitation (RIP) and double luciferase reporter gene assays further verified the interactions.

RESULTS

MK5-AS1 expression was significantly upregulated in HCC tissues and cell lines. Furthermore, high MK5-AS1 expression was positively associated with tumor progression and poor prognosis. In vitro and in vivo experiments confirmed that overexpressed MK5-AS1 promoted migration and invasion of HCC cells. Bioinformatics analysis based on Lncbase, miRDB and TargetScan databases showed MK5-AS1 competitively bound to miR-376b-5p that prevented epithelial cell transforming sequence 2 (ECT2) from miRNA-mediated degradation, thus facilitated HCC metastasis.

CONCLUSION

Our results established a tumor promotive role of MK5-AS1 in HCC pathogenesis.

Pseudogene UBE2MP1 derived transcript enhances in vitro cell proliferation and apoptosis resistance of hepatocellular carcinoma cells through miR-145-5p/RGS3 axis

Pseudogenes are barely transcribed at normal, while the anomalous transcripts of them are mostly regarded as long non-coding RNAs (lncRNAs), which play potential functions in human tumorigenicity and development. The exact effects of pseudogene-derived transcripts on hepatocellular carcinoma (HCC) are ambiguous. According to our previous research and constructed database on the HCC-related lncRNAs, we noticed that UBE2MP1 was transcriptionally activated in HCC as a pseudogene from the ubiquitin-conjugating enzyme member UBE2M. In this study, we validated the high expression of the UBE2MP1 transcript in HCC and its adverse correlation with dismal outcomes for the patients. UBE2MP1 depletion at the transcript level significantly impaired cell proliferation and apoptosis resistance in HCC cell lines. Notably, we discovered that the UBE2MP1 transcript shared a specific sequence, binding to the miR-145-5p seed region with a typical ceRNA effect. Simultaneously, we verified an axis of miR-145-5p/RGS3 in HCC cells, which promoted cell proliferation and apoptosis resistance with significance. And modulation of UE2MP1 could remarkably affect RGS3 expression and consequentially influence HCC cell growth in vitro. And combined with the rescue experiment modulating either miR-145-5p or RGS3 furtherly indicated UBE2MP1 as an upstream regulator of the axis in promoting HCC cell growth and maintenance. Thus, our findings provide new strategies for HCC prevention and individual treatment.

Microarray data analysis to identify miRNA biomarkers and construct the lncRNA-miRNA-mRNA network in lung adenocarcinoma

MicroRNAs (miRNAs), regulatory noncoding RNAs, are involved in gene regulation and may play a role in cancer development. The aim of this study was to identify miRNAs involved in lung adenocarcinoma (LUAD) using bioinformatics analysis. MiRNA (GSE135918), mRNA (GSE136043) and lncRNA (GSE130779) microarray datasets were downloaded from the Gene Expression Omnibus (GEO) database to identify differentially expressed miRNAs (DEMis), mRNAs (DEMs), and lncRNA (DELs) in LUAD. We used DEMs for functional enrichment analysis. MiRNA expression quantification from The Cancer Genome Atlas (TCGA) was used to validate DEMis. LncBase Predicted v.2, Targetscan, and MiRBase were used to predict lncRNAs and mRNAs. The LUAD data in TCGA were used for overall survival (OS) analysis. We screened the downregulation of 8 DEMis and upregulation of 6 DEMis, and found that 70 signal pathways changed. We chose 3 relevant signaling pathways in lung cancer development, WNT, PI3K-Akt, and Notch, and scanned for mRNAs involved in them that are potential targets of these miRNAs. Then a lncRNA-miRNA-mRNA network was constructed. We also found 7 miRNAs that were associated with poor OS in LUAD. Low expression level of hsa-miR-30a was highly associated with poor OS in LUAD (P < .001) and the target genes of hsa-miR-30a-3p were abundant in the Wnt and AKT signaling pathways. In addition, our results reported for the first time that hsa-miR-3944 and hsa-miR-3652 were highly expressed in LUAD. And the high expression level of hsa-miR-3944 was associated with poor OS (P < .05). Hsa-miR-30a-3p may suppress the occurrence and progression of lung cancer through Wnt and AKT signaling pathways and become a good biomarker in LUAD. Hsa-miR-3944 and hsa-miR-3652 may serve as new biomarkers in LUAD.

Single-cell RNA sequencing analysis to explore immune cell heterogeneity and novel biomarkers for the prognosis of lung adenocarcinoma

Background: Single-cell RNA sequencing is necessary to understand tumor heterogeneity, and the cell type heterogeneity of lung adenocarcinoma (LUAD) has not been fully studied.

Method: We first reduced the dimensionality of the GSE149655 single-cell data. Then, we statistically analysed the subpopulations obtained by cell annotation to find the subpopulations highly enriched in tumor tissues. Monocle was used to predict the development trajectory of five subpopulations; beam was used to find the regulatory genes of five branches; qval was used to screen the key genes; and cellchart was used to analyse cell communication. Next, we used the differentially expressed genes of TCGA-LUAD to screen for overlapping genes and established a prognostic risk model through univariate and multivariate analyses. To identify the independence of the model in clinical application, univariate and multivariate Cox regression were used to analyse the relevant HR, 95% CI of HR and p value. Finally, the novel biomarker genes were verified by qPCR and immunohistochemistry.

Results: The single-cell dataset GSE149655 was subjected to quality control, filtration and dimensionality reduction. Finally, 23 subpopulations were screened, and 11-cell subgroups were annotated in 23 subpopulations. Through the statistical analysis of 11 subgroups, five important subgroups were selected, including lung epithelial cells, macrophages, neuroendocrine cells, secret cells and T cells. From the analysis of cell trajectory and cell communication, it is found that the interaction of five subpopulations is very complex and that the communication between them is dense. We believe that these five subpopulations play a very important role in the occurrence and development of LUAD. Downloading the TCGA data, we screened the marker genes of these five subpopulations, which are also the differentially expressed genes in tumorigenesis, with a total of 462 genes, and constructed 10 gene prognostic risk models based on related genes. The 10-gene signature has strong robustness and can achieve stable prediction efficiency in datasets from different platforms. Two new molecular markers related to LUAD, HLA-DRB5 and CCDC50, were verified by qPCR and immunohistochemistry. The results showed that HLA-DRB5 expression was negatively correlated with the risk of LUAD, and CCDC50 expression was positively correlated with the risk of LUAD.

Conclusion: Therefore, we identified a prognostic risk model including CCL20, CP, HLA-DRB5, RHOV, CYP4B1, BASP1, ACSL4, GNG7, CCDC50 and SPATS2 as risk biomarkers and verified their predictive value for the prognosis of LUAD, which could serve as a new therapeutic target.

SPATS2 is positively activated by long noncoding RNA SNHG5 via regulating DNMT3a expression to promote hepatocellular carcinoma progression

Hepatocellular carcinoma (HCC) is one of the most prevalent malignant tumors with high mortality worldwide. Spermatogenesis-associated serine-rich 2 (SPATS2) could be a novel diagnostic and prognostic biomarker in HCC. However, the regulatory mechanism of SPATS2 in HCC requires further elucidation. Therefore, the study’s objective was to investigate this process in HCC. In this study, we found that SPATS2 is significantly upregulated in HepG2 cells to promote cell growth and migration. SPATS2 is the target transcript of lncRNA SNHG5. SPATS2 positively affects the proliferation and migration of HepG2 cells caused by the higher expression of SNHG5. Mechanistically, we identified that the elevated of SPATS2 was attributed to SNHG5 related hypomethylation of SPATS2. SNHG5 reduced the expression of DNMT3a to suppress the methylation level of SPATS2. Taken together, our results uncover a novel epigenetic regulatory mechanism of lncRNA SNHG5-DNMT3a axis-related SPATS2 expression underlying HCC progression. This may serve as a novel prognostic marker and a promising therapeutic target for the treatment of HCC.

Single-cell transcriptomics uncovers an instructive T-cell receptor role in adult γδ T-cell lineage commitment

After entering the adult thymus, bipotent T‐cell progenitors give rise to αβ or γδ T cells. To determine whether the γδ T‐cell receptor (TCR) has an instructive role in γδ T‐cell lineage commitment or only “confirms” a pre‐established γδ Τ‐cell lineage state, we exploited mice lacking expression of LAT, an adaptor required for γδ TCR signaling. Although these mice showed a T‐cell development block at the CD4⁻CD8⁻ double‐negative third (DN3) stage, 0.3% of their DN3 cells expressed intermediate levels of γδ TCR (further referred to as γδ^int) at their surface. Single‐cell transcriptomics of LAT‐deficient DN3 γδ^int cells demonstrated no sign of commitment to the γδ T‐cell lineage, apart from γδ TCR expression. Although the lack of LAT is thought to tightly block DN3 cell development, we unexpectedly found that 25% of LAT‐deficient DN3 γδ^int cells were actively proliferating and progressed up to the DN4 stage. However, even those cells failed to turn on the transcriptional program associated with the γδ T‐cell lineage. Therefore, the γδ TCR‐LAT signaling axis builds upon a γδ T‐cell uncommitted lineage state to fully instruct adult γδ T‐cell lineage specification.

Depleting circ_0088364 restrained cell growth and motility of human hepatocellular carcinoma via circ_0088364-miR-1270-COL4A1 ceRNA pathway

Circular RNA hsa_circ_0088364 (circ_0088364) is a contributory factor in the malignancy of hepatocellular carcinoma (HCC). We aimed to elaborate its role and competing endogenous RNA (ceRNA) mechanism in HCC cell growth and motility. Expression of circ_0088364, microRNA (miR)-1270 and Collagen type IV alpha 1 chain (COL4A1) was measured by real-time quantitative PCR and Western blotting, and their relationships were determined by dual-luciferase reporter assay, RNA immunoprecipitation, biotinylated RNA pull-down, and Spearman's rank correlation analysis. Cellular programs were measured by cell counting kit-8 assay, flow cytometry and transwell assays, Western blotting, and xenograft experiment. Expression of circ_0088364 and COL4A1 was upregulated, and miR-1270 was downregulated in HCC patients' tumors; moreover, there were linear correlations among circ_0088364, miR-1270, and COL4A1 expression. Essentially, circ_0088364 and COL4A1 were ceRNAs for miR-1270 via target binding. In function, silencing circ_0088364 or upregulating miR-1270 could suppress cell proliferation, cell cycle entrance, transwell migration and invasion in Huh7 and HCCLM3 cells, as well as promote apoptosis rate. Moreover, above-mentioned effects were accompanied with reduced B-cell lymphoma (Bcl)-2, N-cadherin and Vimentin levels, and elevated Bcl-2-associated X protein (Bax) and E-cadherin levels. Contrarily, exhausting miR-1270 and restoring COL4A1 could severally abrogate the tumor-suppressive roles of circ_0088364 knockdown and miR-1270 overexpression in HCC cells in vitro. In vivo, silencing circ_0088364 retarded xenograft tumor growth in nude mice induced by Huh7 cells by upregulating miR-1270 and downregulating COL4A1. Blocking circ_0088364 suppressed HCC by inhibiting cell growth and motility via targeting miR-1270-COL4A1 axis.

Current Perspectives on the Unique Roles of Exosomes in Drug Resistance of Hepatocellular Carcinoma

As a common malignant tumor worldwide, the prognosis of hepatocellular carcinoma (HCC) remains unsatisfactory, even though treatment methods have improved. Despite the developments in traditional chemotherapy and emerging targeted immunotherapy, the problem of recurrence and metastasis of HCC and adverse effects on survival and prognosis are still serious. Drug resistance is a daunting challenge that impedes HCC treatment. Exosomes, a class of extracellular vesicles ranging in size from 30 to 100 nm, have been the focus of recent studies. Exosomes can activate various signaling pathways and regulate the tumor microenvironment with their cargo, which includes functional lipids, proteins, and nucleic acids. Thus, they change the phenotype of recipient cells via exosome-mediated communication. Exosomes secreted by tumors or stromal cells can also transfer drug-resistant traits to other tumor cells. However, their effects on drug resistance in HCC are not completely understood. In this review, we summarize and discuss the underlying relationship between exosomes and drug resistance in HCC. In addition, we also show that exosomes may act as candidate biomarkers for predicting and monitoring drug responses and as potential targets or vectors to reverse the drug resistance of HCC.

Expression and Diagnostic Value of miR-497 and miR-1246 in Hepatocellular Carcinoma

Objective

Serum microRNAs (miRNAs) may serve as biomarkers in various cancers. Our study aims to explore the roles of miR-497 and miR-1246 in hepatocellular carcinoma (HCC).

Methods

The expression levels of miR-497 and miR-1246 were measured by RT-PCR. A correlation analysis was conducted between the expression levels of miR-497 and miR-1246 and clinicopathological characteristics of patients. The receiver operating characteristic (ROC) curve was applied to evaluate the diagnostic efficacy in HCC. In addition, bioinformatics tools were also utilized to predict the potential targets of miR-497 and miR-1246.

Results

The expression level of miR-497 in HCC was significantly down-regulated compared with the control group while the miR-1246 revealed a significantly higher expression level in HCC. There was a significant correlation demonstrated between the expression levels of miR-497 and miR-1246 in preoperative serum of HCC and the differentiation degree, Tumor Node Metastasis (TNM) classification, and metastasis. The expression levels of serum miR-497 and miR-1246 were significantly associated with the diagnosis, prognosis, and overall survival rate of patients with HCC. Moreover, the potential target genes of miR-497 in HCC include ARL2, UBE2Q1, PHF19, APLN, CHEK1, CASK, SUCO, CCNE1, and KIF23. The low expression of these nine genes is associated with a better prognosis of HCC patients. AUTS2 is a novel target gene of miR-1246, and its low expression is significantly related to the low overall survival rate of HCC patients.

Conclusions

miR-497 and miR-1246 are possibly involved in the progression of HCC by regulating target genes, respectively, and could serve as biomarkers in HCC.

microRNA-145-5p Inhibits Migration, Invasion, and Metastasis in Hepatocellular Carcinoma by Inhibiting ARF6

Purpose

Hepatocellular carcinoma (HCC) has the fourth highest rate of mortality among the different types of cancer worldwide. This study aimed to investigate the functions of microRNA-145-5p and AFR6 on migration, invasion and metastasis in HCC.

Methods

A total of 150 pairs of tumor and their matched adjacent nontumor liver tissues were collected from HCC patients. Expressions of microRNA-145-5p and AFR6 were measured by real-time PCR in HCC tissues and in HCC cell lines. The correlations between microRNA-145-5p and HCC prognosis were investigated. The proliferation, migration, invasion, cell cycle progression, and apoptosis of HCCLM3 cells were evaluated with CCK8, wound healing, transwell, and flow cytometric experiments.

Results

The expression of miR-145-5p was confirmed to be downregulated not only in HCC tissues but also in several HCC cell lines compared with normal controls. A low expression level of miR-145-5p was notably associated with poor prognosis in patients with HCC and certain characteristics of metastatic tumors. In vitro, miR-145-5p negatively regulated cell proliferation, migration, and invasion and induced apoptosis in HCCLM3 cells. Subsequent experiments further verified that ARF6 is a novel target of miR-145-5p and is significantly overexpressed in HCC tissues. Overexpression of ARF6 circumvented the effects of miR-145-5p in HCCLM3 cells.

Conclusion

miR-145-5p may play a pivotal role in HCC metastasis via regulating ARF6, and these findings may both provide further insights into the key factors of HCC metastasis and prove to be useful in the development of novel treatment options for HCC.

Current perspectives on exosomes in the diagnosis and treatment of hepatocellular carcinoma (review)

The prognosis of hepatocellular carcinoma (HCC), a malignant tumor, is poor. Tumor recurrence and metastasis are the major challenges for the treatment of HCC. Various studies have demonstrated that exosomes, which are loaded with various biomolecules including nucleic acids, lipids, and proteins are involved in the recurrence and metastasis of HCC. Additionally, exosomes mediate various biological processes, such as immune response, cell apoptosis, angiogenesis, thrombosis, autophagy, and intercellular signal transduction. In cancer, exosomes regulate cancer cell differentiation, development, and drug resistance. Circular RNAs, microRNAs, and proteins in the exosomes can serve as early diagnostic and prognostic markers for HCC. As exosomes are characterized by low immunogenicity and high stability in the tissues and circulation, they can be used to deliver the drugs in cancer therapies.

Role of chemokines in hepatocellular carcinoma (Review)

Hepatocellular carcinoma (HCC) is a prevalent malignant tumor worldwide, with an unsatisfactory prognosis, although treatments are improving. One of the main challenges for the treatment of HCC is the prevention or management of recurrence and metastasis of HCC. It has been found that chemokines and their receptors serve a pivotal role in HCC progression. In the present review, the literature on the multifactorial roles of exosomes in HCC from PubMed, Cochrane library and Embase were obtained, with a specific focus on the functions and mechanisms of chemokines in HCC. To date, >50 chemokines have been found, which can be divided into four families: CXC, CX3C, CC and XC, according to the different positions of the conserved N‑terminal cysteine residues. Chemokines are involved in the inflammatory response, tumor immune response, proliferation, invasion and metastasis via modulation of various signaling pathways. Thus, chemokines and their receptors directly or indirectly shape the tumor cell microenvironment, and regulate the biological behavior of the tumor. In addition, the potential application of chemokines in chemotaxis of exosomes as drug vehicles is discussed. Exosomes containing chemokines or expressing receptors for chemokines may improve chemotaxis to HCC and may thus be exploited for targeted drug delivery.