Exosomal microRNA-32-5p induces multidrug resistance in hepatocellular carcinoma via the PI3K/Akt pathway

MiR-1246 is responsible for lung cancer cells-derived exosomes-mediated promoting effects on lung cancer stemness via targeting TRIM17

The stemness of lung cancer cells contributes to drug resistance, tumor occurrence, progression, and recurrence; however, the underlying mechanisms are still fragmentary. In the present study, it was found that exosomes from cisplatin-resistant cells and spheres derived from lung cancer cells enhanced the stemness of the parental lung cancer cells. Then we screened the upregulated miRNAs in spheres derived from lung cancer cells and cisplatin-resistant lung cancer cells/exosomes compared to that in the parental lung cancer cells. It was found that miR-1246 was remarkably enriched in cisplatin-resistant lung cancer cells/exosomes and spheres. Additionally, inhibition of miR-1246 attenuated the stemness of lung cancer cells induced by exosomes from cisplatin-resistant cells and spheres. Furthermore, TRIM17 was identified to the direct target of miR-1246 in lung cancer cells. Our findings suggest that exosomal miR-1246 could be as a potential target for lung cancer treatment.

H-TEX-mediated signaling between hepatocellular carcinoma cells and macrophages and exosome-targeted therapy for hepatocellular carcinoma

There is increasing evidence for the key role of the immune microenvironment in the occurrence and development of hepatocellular carcinoma. As an important component of the immune microenvironment, the polarization state and function of macrophages determine the maintenance of the immunosuppressive tumor microenvironment. Hepatocellular carcinoma tumor-derived exosomes, as information carriers, regulate the physiological state of cells in the microenvironment and control cancer progression. In this review, we focus on the role of the exosome content in disease outcomes at different stages in the progression of hepatitis B virus/hepatitis C virus-induced hepatocellular carcinoma. We also explore the mechanism by which macrophages contribute to the formation of hepatocellular carcinoma and summarize the regulation of macrophage functions by the heterogeneity of exosome loading in liver cancer. Finally, with the rise of exosome modification in immunotherapy research on hepatocellular carcinoma, we summarize the application prospects of exosome-based targeted drug delivery.

Non-coding RNAs in hepatocellular carcinoma: Insights into regulatory mechanisms, clinical significance, and therapeutic potential

Hepatocellular carcinoma (HCC) is a complex and heterogeneous malignancy with high incidence and poor prognosis. In addition, owing to the lack of diagnostic and prognostic markers, current multimodal treatment options fail to achieve satisfactory outcomes. Tumor immune microenvironment (TIME), angiogenesis, epithelial-mesenchymal transition (EMT), invasion, metastasis, metabolism, and drug resistance are important factors influencing tumor development and therapy. The intercellular communication of these important processes is mediated by a variety of bioactive molecules to regulate pathophysiological processes in recipient cells. Among these bioactive molecules, non-coding RNAs (ncRNAs), including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), account for a large part of the human transcriptome, and their dysregulation affects the progression of HCC. The purpose of this review is to evaluate the potential regulatory mechanisms of ncRNAs in HCC, summarize novel biomarkers from somatic fluids (plasma/serum/urine), and explore the potential of some small-molecule modulators as drugs. Thus, through this review, we aim to contribute to a deeper understanding of the regulatory mechanisms, early diagnosis, prognosis, and precise treatment of HCC.

Vincosamide Has a Function for Inhibiting Malignant Behaviors of Hepatocellular Carcinoma Cells

BACKGROUND

Vincosamide (Vinco) was first identified in the methanolic extract of the leaves of Psychotria leiocarpa, and Vinco has important anti-inflammatory effects and activity against cholinesterase, Vinco also has a trait to anti-tumor. However, whether Vinco can inhibit the malignant behaviors of hepatocellular carcinoma (HCC) cells is still unclear. In the present study, we explored the role of Vinco in suppressing the malignant behaviors of HCC cells.

METHODS

MTT (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl-tetrazolium bromide), trypan blue exclusion assay, the Cell Counting Kit (CCK)-8 and flow cytometric analysis were applied to detect the proliferation and apoptosis of HCC cells; electron microscopy was performed to observe the change of cellular mitochondrial morphology; scratch repair and Transwell assays were used to analyze the migration and invasion of HCC cells; expression and localization of proteins were detected by laser confocal microscopy and Western blotting; the growth of the cancer cells in vivo was assessed in a mouse tumorous model.

RESULTS

At a dose of 10 - 80 µg/mL, Vinco inhibited the proliferation, migration, invasion and promoted apoptosis of HCC cells in a dose-dependent manner but had low cytotoxicity effect on normal liver cells. Additionally, 80 µg/mL of Vinco could significantly disrupt the morphology of mitochondria, suppress the migration and invasion of HCC cells. The growth of HCC cells in the animal tumorous model was significantly inhibited after treatment with Vinco (10 mg/kg/day) for 3 days. The results of the present study indicated that Vinco (10 - 80 µg/mL) played a role in activating caspase-3, promoting the expression of phosphate and tension homology deleted on chromosome 10 (PTEN), and inhibiting the phosphorylation of AKT (Ser473) and mTOR (Thr2448); Vinco also has a trait for suppressing the expression of CXCR4, Src, MMP9, EpCAM, Ras, Oct4 and cancer stem cell "stemness markers" CD133 and CD44 in HCC cells.

CONCLUSIONS

Vinco has a role in inhibiting the malignant behaviors of HCC cells; the role molecular mechanism of Vinco may be involved in restraining expression of the growth-, metastasis-related factors, such as Src, Ras, MMP9, EpCAM, CXCR4; activating the activity of caspase-3 and blocking PI3K/AKT signaling pathway. Thus, Vinco should be considered as a new chemotherapy agent for HCC patients.

The emerging roles of extracellular vesicles as intercellular messengers in liver physiology and pathology

Extracellular vesicles (EVs) are membrane-enclosed particles released from almost all cell types. EVs mediate intercellular communication by delivering their surface and luminal cargoes, including nucleic acids, proteins, and lipids, which reflect the pathophysiological conditions of their cellular origins. Hepatocytes and hepatic non-parenchymal cells utilize EVs to regulate a wide spectrum of biological events inside the liver and transfer them to distant organs through systemic circulation. The liver also receives EVs from multiple organs and integrates these extrahepatic signals that participate in pathophysiological processes. EVs have recently attracted growing attention for their crucial roles in maintaining and regulating hepatic homeostasis. This review summarizes the roles of EVs in intrahepatic and interorgan communications under different pathophysiological conditions of the liver, with a focus on chronic liver diseases including nonalcoholic steatohepatitis, alcoholic hepatitis, viral hepatitis, liver fibrosis, and hepatocellular carcinoma. This review also discusses recent progress for potential therapeutic applications of EVs by targeting or enhancing EV-mediated cellular communication for the treatment of liver diseases.

Feasibility of hepatocellular carcinoma treatment based on the tumor microenvironment

The incidence of liver cancer is extremely high worldwide and poses a serious threat to human life and health. But at present, apart from radiotherapy, chemotherapy, liver transplantation, and early resection, sorafenib was the main systemic therapy proven to have clinical efficacy for unresectable liver cancer (HCC) until 2017. Despite the emerging immunotherapy in the past decade with immune inhibitors such as PD - 1 being approved and applied to clinical treatment, there are still some patients with no response. This review aims to elucidate the mechanisms underlying the tumor microenvironment of hepatocellular carcinoma and thus analyze the effectiveness of targeting the tumor microenvironment to improve the therapeutic efficacy of hepatocellular carcinoma, including the effectiveness and feasibility of immunotherapy, tumor oncolytic viruses and anti-vascular proliferation therapy.

MicroRNA-20a-5p regulates the epithelial-mesenchymal transition of human hepatocellular carcinoma by targeting RUNX3

BACKGROUND

MicroRNA-20a (miR-20a) is dysregulated in many types of malignancies, including human hepatocellular carcinoma (HCC), but its expression level and functional significance in HCC are still disputed. We aimed to study the role of miR-20a-5p in HCC and its downstream molecular mechanisms.

METHODS

We used real-time polymerase chain reaction to detect the expression of miR-20a-5p and runt-related transcription factor 3 ( RUNX3 ) in HCC and paraneoplastic tissue, transfected Huh7 and highly metastatic human hepatocellular carcinoma (MHCC97H) cells. A live cell workstation was used to observe the proliferation and migration of transfected cells. The invasiveness of transfected cells was verified by Transwell assay. Cell apoptosis was detected by flow cytometry. The expression levels of proteins after transfection were measured using simple western immunoblot measurements. Gene expression profiles between HCC and normal samples were obtained from The Cancer Genome Atlas. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment results were processed by the database for annotation, visualization and integrated discovery. Potential target genes of miR-20a-5p were predicted to further investigate how miR-20a-5p regulates epithelial-mesenchymal transition (EMT) in HCC.

RESULTS

MiR-20a-5p was significantly highly expressed in HCC tissues, and overexpression of miR-20a-5p significantly promoted HCC cell proliferation, migration, and invasion and inhibited apoptosis in vitro. The protein expression of E-cadherin was decreased and that of vimentin was increased after overexpression of miR-20a-5p in HCC cells. We discovered the intersection of genes from miRDB, miR TarBase, and TargetScan, obtained 397 target genes and finally focused on RUNX3. RUNX3 was not only reduced in HCC specimens but also drastically reduced in HCC cells overexpressing miR-20a-5p. RUNX3 expression decreased with elevated miR-20a-5p, which activated downstream EMT signaling and promoted cell proliferation, migration, and invasion.

CONCLUSIONS

Since RUNX3 is involved in EMT in HCC, as proven by previous research, our findings provide further evidence for a novel regulatory pathway comprising the miR-20a/RUNX3/EMT axis that upregulates EMT signaling and enhances the migration of HCC cells.

Intercellular communication in the tumour microecosystem: Mediators and therapeutic approaches for hepatocellular carcinoma

Hepatocellular carcinoma (HCC), one of the most common tumours worldwide, is one of the main causes of mortality in cancer patients. There are still numerous problems hindering its early diagnosis, which lead to late patients receiving treatment, and these problems need to be solved urgently. The tumour microecosystem is a complex network system comprising seven parts: the hypoxia niche, immune microenvironment, metabolic microenvironment, acidic niche, innervated niche, mechanical microenvironment, and microbial microenvironment. Intercellular communication is divided into direct contact and indirect communication. Direct contact communication includes gap junctions, tunneling nanotubes, and receptor-ligand interactions, whereas indirect communication includes exosomes, apoptotic vesicles, and soluble factors. Mechanical communication and cytoplasmic exchange are further means of intercellular communication. Intercellular communication mediates the crosstalk between the tumour microecosystem and the host as well as that between cells and cell-free components in the tumour microecosystem, causing changes in the tumour hallmarks of the HCC microecosystem such as changes in tumour proliferation, invasion, apoptosis, angiogenesis, metastasis, inflammatory response, gene mutation, immune escape, metabolic reprogramming, and therapeutic resistance. Here, we review the role of the above-mentioned intercellular communication in the HCC microecosystem and discuss the advantages of targeted intercellular communication in the clinical diagnosis and treatment of HCC. Finally, the current problems and prospects are discussed.

Alternating exosomes and their mimetics as an emergent strategy for targeted cancer therapy

Exosomes, a subtype of the class of extracellular vesicles and nano-sized particles, have a specific membrane structure that makes them an alternative proposition to combat with cancer through slight modification. As constituents of all most all the primary body fluids, exosomes establish the status of intercellular communication. Exosomes have specific proteins/mRNAs and miRNAs which serve as biomarkers, imparting a prognostic tool in clinical and disease pathologies. They have efficient intrinsic targeting potential and efficacy. Engineered exosomes are employed to deliver therapeutic cargos to the targeted tumor cell or the recipient. Exosomes from cancer cells bring about changes in fibroblast via TGFβ/Smad pathway, augmenting the tumor growth. These extracellular vesicles are multidimensional in terms of the functions that they perform. We herein discuss the uptake and biogenesis of exosomes, their role in various facets of cancer studies, cell-to-cell communication and modification for therapeutic and diagnostic use.

Noncoding RNA-mediated molecular bases of chemotherapy resistance in hepatocellular carcinoma

Despite the significant progress in decreasing the occurrence and mortality of hepatocellular carcinoma (HCC), it remains a public health issue worldwide on the basis of its late presentation and tumor recurrence. To date, apart from surgical interventions, such as surgical resection, liver transplantation and locoregional ablation, current standard antitumor protocols include conventional cytotoxic chemotherapy. However, due to the high chemoresistance nature, most current therapeutic agents show dismal outcomes for this refractory malignancy, leading to disease relapse. Nevertheless, the molecular mechanisms involved in chemotherapy resistance remain systematically ambiguous. Herein, HCC is hierarchically characterized by the formation of primitive cancer stem cells (CSCs), progression of epithelial-mesenchymal transition (EMT), unbalanced autophagy, delivery of extracellular vesicles (EVs), escape of immune surveillance, disruption of ferroptosis, alteration of the tumor microenvironment and multidrug resistance-related signaling pathways that mediate the multiplicity and complexity of chemoresistance. Of note, anecdotal evidence has corroborated that noncoding RNAs (ncRNAs) extensively participate in the critical physiological processes mentioned above. Therefore, understanding the detailed regulatory bases that underlie ncRNA-mediated chemoresistance is expected to yield novel insights into HCC treatment. In the present review, a comprehensive summary of the latest progress in the investigation of chemotherapy resistance concerning ncRNAs will be elucidated to promote tailored individual treatment for HCC 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.

Endometrial Carcinoma: Molecular Cytogenetics and Transcriptomic Profile

Endometrial carcinomas (ECs) are histologically classified as endometrioid and nonendometrioid tumors, with each subgroup displaying different molecular profiles and clinical outcomes. Considerable biological and clinical heterogeneity exists within this scheme, however, reflecting its imperfection. We aimed to gather additional data that might help clarify the tumors’ pathogenesis and contribute toward a more meaningful classification scheme. In total, 33 ECs were examined for the presence of chromosomal aberrations, genomic imbalances, pathogenic variants, microsatellite instability, and expression profiles at both gene and miRNA levels. Chromosome 1 was the most frequently rearranged chromosome, showing a gain of all or part of the long arm. Pathogenic variants were found for PTEN (53%), PDGFRA (37%), PIK3CA (34%), and KIT (31%). High microsatellite instability was identified in 15 ECs. Comparing tumors and controls, we identified 23 differentially expressed genes of known importance in carcinogenesis, 15 genes involved in innate and adaptative immune responses, and altered expression of 7 miRNAs. miR-32-5p was the most upregulated. Our series showed a high degree of heterogeneity. Tumors were well-separated from controls, but there was no clear-cut separation between endometrioid and nonendometrioid ECs. Whether this means that the current phenotypic classification is of little relevance or if one still has not detected which genomic parameters to enter into correlation analyses remains unknown.

Role of exosomal microRNAs in cancer therapy and drug resistance mechanisms: focus on hepatocellular carcinoma

Extracellular vesicles (EVs), defined as intercellular messengers that carry their cargos between cells, are involved in several physiological and pathological processes. These small membranous vesicles are released by most cells and contain biological molecules, including nucleic acids, proteins and lipids, which can modulate signaling pathways of nearby or distant recipient cells. Exosomes, one the most characterized classes of EVs, include, among others, microRNAs (miRNAs), small non-coding RNAs able to regulate the expression of several genes at post-transcriptional level. In cancer, exosomal miRNAs have been shown to influence tumor behavior and reshape tumor microenvironment. Furthermore, their possible involvement in drug resistance mechanisms has become evident in recent years. Hepatocellular carcinoma (HCC) is the major type of liver cancer, accounting for 75-85% of all liver tumors. Although the improvement in HCC treatment approaches, low therapeutic efficacy in patients with intermediate-advanced HCC is mainly related to the development of tumor metastases, high risk of recurrence and drug resistance. Exosomes have been shown to be involved in pathogenesis and progression of HCC, as well as in drug resistance, by regulating processes such as cell proliferation, epithelial-mesenchymal transition and immune response. Herein, we summarize the current knowledge about the involvement of exosomal miRNAs in HCC therapy, highlighting their role as modulators of therapeutic response, particularly chemotherapy and immunotherapy, as well as possible therapeutic tools.

Exosomal circWDR62 promotes temozolomide resistance and malignant progression through regulation of the miR-370-3p/MGMT axis in glioma

Exosome-mediated delivery of circular RNAs (circRNAs) is implicated in cancer progression. However, the role of exosomal circRNAs in the chemotherapy resistance of tumours remains poorly understood. Here we identified a novel circRNA, circWDR62. It was found that circWDR62 expression was upregulated in TMZ-resistant glioma cells and TMZ-resistant glioma cell-derived exosomes compared with their controls by using high-throughput microarray analysis and quantitative real-time polymerase chain reaction, and high circWDR62 expression was associated with poor prognosis of glioma. Functionally, downregulation of circWDR62 expression could significantly inhibit the TMZ resistance and malignant progression of glioma. Further mechanistic studies showed that circWDR62 plays a role by sponging miR-370-3p as a competing endogenous RNA. Rescue experiments confirmed that MGMT is the downstream target of the circWDR62/miR-370-3p axis in glioma. In addition, circWDR62 could be transported between TMZ-resistant and TMZ-sensitive glioma cells via exosomes. Exosomal circWDR62 from TMZ-resistant cells conferred TMZ resistance in recipient sensitive cells while also enhancing the proliferation, migration and invasion of these cells. A series of clinical and in vivo trials corroborated that exosomal circWDR62 could promote TMZ chemoresistance and malignant progression of glioma. Our results demonstrate for the first time that exosome-mediated delivery of circWDR62 can promote TMZ resistance and malignant progression via targeting of the miR-370-3p/MGMT axis in vitro and in vivo in glioma, providing a new therapeutic strategy. Moreover, exosomal circWDR62 in human serum may serve as a promising therapeutic target and prognostic marker for glioma therapy.

Exosomal miRNA Expression Profiling and the Roles of Exosomal miR-4741, miR-32, miR-3149, and miR-6727 on Gastric Cancer Progression

Objective

Accumulated evidence highlights the biological implications of exosomes in gastric cancer. Herein, we conducted the exosomal miRNA expression profiling and identified potential diagnostic markers for gastric cancer.

Methods

Plasma exosomes were isolated and identified from three gastric cancer patients and three healthy participants. Microarrays of exosomal miRNAs were then analyzed. Differentially expressed exosomal miRNAs were screened with fold − change|≥2.0 and p ≤ 0.05. Among them, miR-4741, miR-32, miR-3149, and miR-6727 expressions were verified in tissues and plasma of patients and healthy subjects. ROC curves were conducted for evaluating the diagnostic performance. The roles of miR-32, miR-3149, miR-6727, and miR-4741 on gastric cancer progression were observed by cellular experiments.

Results

Isolated exosomes were well characterized by Western blot and transmission electron microscopy as well as nanoparticle-tracking analyses. According to the microarrays, 142 exosomal miRNAs were upregulated, and 34 were downregulated in gastric cancer than healthy subjects. miR-4741 upregulation and miR-32, miR-3149, and miR-6727 downregulations were found in tissues and plasma of gastric cancer patients. The AUCs of miR-4741, miR-32, miR-3149, and miR-6727 were separately 0.8554, 0.9456, 0.7683, and 0.8923. Upregulated miR-32, miR-3149, and miR-6727 as well as downregulated miR-4741 lowered proliferative, migratory, and invasive capacities as well as elevated apoptotic levels of gastric cancer cells.

Conclusion

Our study successfully isolated and verified exosomes from plasma of gastric cancer as well as proposed four exosomal miRNAs that could act as promising diagnostic markers and suppress gastric cancer progression.

MiRNAs in Lung Cancer: Diagnostic, Prognostic, and Therapeutic Potential

Lung cancer is the dominant emerging factor in cancer-related mortality around the globe. Therapeutic interventions for lung cancer are not up to par, mainly due to reoccurrence/relapse, chemoresistance, and late diagnosis. People are currently interested in miRNAs, which are small double-stranded (20–24 ribonucleotides) structures that regulate molecular targets (tumor suppressors, oncogenes) involved in tumorigeneses such as cell proliferation, apoptosis, metastasis, and angiogenesis via post-transcriptional regulation of mRNA. Many studies suggest the emerging role of miRNAs in lung cancer diagnostics, prognostics, and therapeutics. Therefore, it is necessary to intensely explore the miRNOME expression of lung tumors and the development of anti-cancer strategies. The current review focuses on the therapeutic, diagnostic, and prognostic potential of numerous miRNAs in lung cancer.

Exosomal miR-4800-3p Aggravates the Progression of Hepatocellular Carcinoma via Regulating the Hippo Signaling Pathway by Targeting STK25

Background

Emerging evidence has shown that exosome microRNAs (miRNAs) regulate the development of hepatocellular carcinoma (HCC). Here, the influences of miR-4800-3p on the progression of HCC were explored.

Materials and Methods

The expression of miR-4800-3p in the exosome derived by transforming growth factor beta 1 (TGF-β1)-treated HCC cells and the serum exosome isolated from HCC patients were identified by real-time PCR. The effects of TGF-β1 and the influences of Huh7-secreted exosomes and the effects of miR-4800-3p combined with/without STK25 on cell functions were explored using the EdU assay cloning experiments, wound healing assay, and Transwell assay. The corresponding molecular mechanisms were further detected using Western blot and real-time PCR assays. The combination of miR-4800-3p and STK25 was verified by the dual-luciferase and RNA pulldown assays. The influences of miR-4800-3p on the growth and epithelial–mesenchymal transformation (EMT) of implanted tumors were tested in vivo and further confirmed by Western blot.

Results

The miR-4800-3p expression was highly expressed in both exosomes derived by TGF-β1-treated HCC cells and the serum exosomes of HCC patients. In the cases of treatment with both Huh7-derived exosomes, the level of miR-4800-3p expression was highest, and the treatment of TGF-β1 could greatly promote the proliferation, stemness, migration, and invasion of HCC cells via upregulating the markers of stemness and EMT, including CD44, CD133, OCT4, N-cadherin, E-cadherin, and ZO-1. Similar results could be obtained when miR-4800-3p was overexpressed in HCC cells. Furthermore, downregulation of STK25 expression, a direct target gene of miR-4800-3p, could greatly rescue the malignant biological behaviors aggravated by overexpression of miR-4800-3p. This was achieved by suppressing the expression of CD44, CD133, OCT4, N-cadherin, and PCNA and activating the Hippo pathway while increasing E-cadherin and ZO-1. Similar results were also obtained in vivo that knockdown of miR-4800-3p expression suppressed tumor growth induced by Huh7-derived exosomes by mediating the EMT markers and the Hippo signaling pathway.

Conclusion

Exosomal miR-4800-3p could accelerate HCC development by regulating the Hippo signal by targeting STK25, which could be used as a new therapeutic target for HCC treatment.

Tumor-associated Exosomes Are Involved in Hepatocellular Carcinoma Tumorigenesis, Diagnosis, and Treatment

Hepatocellular carcinoma (HCC) has become a challenging disease worldwide. There are still limitations in the diagnosis and treatment of HCC, and its high metastatic capacity and high recurrence rate are the main reasons for its poor prognosis. The ability of extracellular vesicles (EVs) to transfer functionally-active substances and their widespread presence in almost all body fluids suggest their unprecedented potential in the study of various cancers. The unique physicochemical properties of EVs determine their potential as antitumor vaccines and drug carriers. In the last decade, the study of EVs in HCC has evolved from a single hot topic to a system with considerable scale. This paper summarizes the role of EVs, especially exosomes, in the occurrence, metastasis and tumor immunity of HCC, reviews their applications in tumor diagnosis, prognosis and treatment, describes the pros and cons of these studies, and looks forward towards the future research directions of EVs in HCC.

miRNAs as cornerstones in colorectal cancer pathogenesis and resistance to therapy: A spotlight on signaling pathways interplay - A review

Colorectal cancer (CRC) is the world's third most prevalent cancer and the main cause of cancer-related mortality. A lot of work has been put into improving CRC patients' clinical care, including the development of more effective methods and wide biomarkers variety for prognostic, and diagnostic purposes. MicroRNAs (miRNAs) regulate a variety of cellular processes and play a significant role in the CRC progression and spread via controlling their target gene expression by translation inhibition or mRNA degradation. Consequently, dysregulation and disruption in their function, miRNAs are linked to CRC malignant pathogenesis by controlling several cellular processes involved in the CRC. These cellular processes include increased proliferative and invasive capacity, cell cycle aberration, evasion of apoptosis, enhanced EMT, promotion of angiogenesis and metastasis, and decreased sensitivity to major treatments. The miRNAs control cellular processes in CRC via regulation of pathways such as Wnt/β-catenin signaling, PTEN/AKT/mTOR axis, KRAS, TGFb signaling, VEGFR, EGFR, and P53. Hence, the goal of this review was to review miRNA biogenesis and present an updated summary of oncogenic and tumor suppressor (TS) miRNAs and their potential implication in CRC pathogenesis and responses to chemotherapy and radiotherapy. We also summarise the biological importance and clinical applications of miRNAs in the CRC.

Extracellular Vesicles and Resistance to Anticancer Drugs: A Tumor Skeleton Key for Unhinging Chemotherapies

Although surgical procedures and clinical care allow reaching high success in fighting most tumors, cancer is still a formidable foe. Recurrence and metastatization dampen the patients’ overall survival after the first diagnosis; nevertheless, the large knowledge of the molecular bases drives these aspects. Chemoresistance is tightly linked to these features and is mainly responsible for the failure of cancer eradication, leaving patients without a crucial medical strategy. Many pathways have been elucidated to trigger insensitiveness to drugs, generally associated with the promotion of tumor growth, aggressiveness, and metastatisation. The main mechanisms reported are the expression of transporter proteins, the induction or mutations of oncogenes and transcription factors, the alteration in genomic or mitochondrial DNA, the triggering of autophagy or epithelial-to-mesenchymal transition, the acquisition of a stem phenotype, and the activation of tumor microenvironment cells. Extracellular vesicles (EVs) can directly transfer or epigenetically induce to a target cell the molecular machinery responsible for the acquisition of resistance to drugs. In this review, we resume the main body of knowledge supporting the crucial role of EVs in the context of chemoresistance, with a particular emphasis on the mechanisms related to some of the main drugs used to fight cancer.

MiR-181c sensitizes ovarian cancer cells to paclitaxel by targeting GRP78 through the PI3K/Akt pathway

Primary cytoreductive surgery with platinum-taxane-based chemotherapy is the standard treatment for ovarian cancer (OC) patients; however, resistance to chemotherapy is a contributing factor to OC mortality. Paclitaxel (PTX), the most widely used taxane, has become the first-line drug against OC. The molecular mechanism of PTX resistance is different from that of platinum-based agents and is still not completely elucidated. Our previous study showed that glucose-regulated protein 78 (GRP78) is involved in the resistance of OC cells to PTX. However, little is known regarding endogenous inhibitors of this gene. MicroRNAs (miRNAs) play critical roles in the regulation of gene expression; therefore, we sought to identify miRNA(s) with potential to target GRP78 under the hypothesis that miRNA(s) could serve as potential therapeutic targets. Here, we show that miR-181c, predicted to target GRP78, was downregulated in PTX-resistant OC cells and tissues. MiR-181c downregulated GRP78 expression and induced apoptosis by directly targeting its 3'-untranslated region (UTR). Overexpression of miR-181c sensitized resistant OC to PTX by inhibiting the PI3K/Akt pathway in vitro and in vivo. Taken together, our findings indicate that the delivery of miR-181c can efficiently suppress GRP78 expression and GRP78-mediated PTX resistance in OC and suggest that this strategy has therapeutic potential.

Exosomal MiRNAs in Osteosarcoma: Biogenesis and Biological Functions

MiRNAs are a group of non-coding RNA molecules that function in mRNA translational inhibition via base-pairing with complementary sequences in target mRNA. In oncology, miRNAs have raised great attention due to their aberrant expression and pivotal roles in the pathogenesis of multiple malignancies including osteosarcoma. MiRNAs can be transported by exosome, the nano-extracellular vesicle with a diameter of 30–150 nm. Recently, a growing number of studies have demonstrated that exosomal miRNAs play a critical role in tumor initiation and progression, by exerting multiple biological functions including metastasis, angiogenesis, drug resistance and immunosuppression. In this review, we aim to depict the biogenesis of exosomal miRNAs and summarize the potential diagnostic and therapeutic functions of exosomal miRNAs in osteosarcoma.

A network-based matrix factorization framework for ceRNA co-modules recognition of cancer genomic data

With the development of high-throughput technologies, the accumulation of large amounts of multidimensional genomic data provides an excellent opportunity to study the multilevel biological regulatory relationships in cancer. Based on the hypothesis of competitive endogenous ribonucleic acid (RNA) (ceRNA) network, lncRNAs can eliminate the inhibition of microRNAs (miRNAs) on their target genes by binding to intracellular miRNA sites so as to improve the expression level of these target genes. However, previous studies on cancer expression mechanism are mostly based on individual or two-dimensional data, and lack of integration and analysis of various RNA-seq data, making it difficult to verify the complex biological relationships involved. To explore RNA expression patterns and potential molecular mechanisms of cancer, a network-regularized sparse orthogonal-regularized joint non-negative matrix factorization (NSOJNMF) algorithm is proposed, which combines the interaction relations among RNA-seq data in the way of network regularization and effectively prevents multicollinearity through sparse constraints and orthogonal regularization constraints to generate good modular sparse solutions. NSOJNMF algorithm is performed on the datasets of liver cancer and colon cancer, then ceRNA co-modules of them are recognized. The enrichment analysis of these modules shows that >90% of them are closely related to the occurrence and development of cancer. In addition, the ceRNA networks constructed by the ceRNA co-modules not only accurately mine the known correlations of the three RNA molecules but also further discover their potential biological associations, which may contribute to the exploration of the competitive relationships among multiple RNAs and the molecular mechanisms affecting tumor development.

Extracellular Vesicles and Cell Pathways Involved in Cancer Chemoresistance

Chemoresistance is a pharmacological condition that allows transformed cells to maintain their proliferative phenotype in the presence of administered anticancer drugs. Recently, extracellular vesicles, including exosomes, have been identified as additional players responsible for the chemoresistance of cancer cells. These are nanovesicles that are released by almost all cell types in both physiological and pathological conditions and contain proteins and nucleic acids as molecular cargo. Extracellular vesicles released in the bloodstream reach recipient cells and confer them novel metabolic properties. Exosomes can foster chemoresistance by promoting prosurvival and antiapoptotic pathways, affecting cancer stem cells and immunotherapies, and stimulating drug efflux. In this context, a crucial role is played by membrane transporters belonging to ABC, SLC, and P-type pump families. These proteins are fundamental in cell metabolism and drug transport in either physiological or pathological conditions. In this review, different roles of extracellular vesicles in drug resistance of cancer cells will be explored.

miRNAs inspirations in hepatocellular carcinoma: Detrimental and favorable aspects of key performers

Hepatocellular carcinoma (HCC) is the fourth leading cause of cancer-related deaths worldwide. HCC initiation, progression, and therapy failure are all influenced by various variables, including microRNAs (miRNAs). miRNAs are short non-coding RNA sequences that modulate target mRNA expression by deteriorating or repressing translation. miRNAs play an imperative role in HCC pathogenesis by triggering the induction of cancer stem cells (CSCs) and their proliferation, while also delaying apoptosis, sustaining the cell cycle, and inspiring angiogenesis, invasion, and metastasis. Additionally, miRNAs modulate crucial HCC-related molecular pathways such as the p53 pathway, the Wnt/β-catenin pathway, VEGFR2, and PTEN/PI3K/AKT pathway. Consequently, the goal of this review was to give an up-to-date overview of oncogenic and tumor suppressor (TS) miRNAs, as well as their potential significance in HCC pathogenesis and treatment responses, highlighting their underpinning molecular pathways in HCC initiation and progression. Similarly, the biological importance and clinical application of miRNAs in HCC are summarized.

Exosome-Mediated Therapeutic Strategies for Management of Solid and Hematological Malignancies

Exosomes are small membrane vesicles of endocytic origin containing cytokines, RNAs, growth factors, proteins, lipids, and metabolites. They have been identified as fundamental intercellular communication controllers in several diseases and an enormous volume of data confirmed that exosomes could either sustain or inhibit tumor onset and diffusion in diverse solid and hematological malignancies by paracrine signaling. Thus, exosomes might constitute a promising cell-free tumor treatment alternative. This review focuses on the effects of exosomes in the treatment of tumors, by discussing the most recent and promising data from in vitro and experimental in vivo studies and the few existing clinical trials. Exosomes are extremely promising as transporters of drugs, antagomir, genes, and other therapeutic substances that can be integrated into their core via different procedures. Moreover, exosomes can augment or inhibit non-coding RNAs, change the metabolism of cancer cells, and modify the function of immunologic effectors thus modifying the tumor microenvironment transforming it from pro-tumor to antitumor milieu. Here, we report the development of currently realized exosome modifiers that offer indications for the forthcoming elaboration of other more effective methods capable of enhancing the activity of the exosomes.

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.

Noncoding RNAs of Extracellular Vesicles in Tumor Angiogenesis: From Biological Functions to Clinical Significance

Extracellular vesicles (EVs) act as multifunctional regulators of intercellular communication and are involved in diverse tumor phenotypes, including tumor angiogenesis, which is a highly regulated multi-step process for the formation of new blood vessels that contribute to tumor proliferation. EVs induce malignant transformation of distinct cells by transferring DNAs, proteins, lipids, and RNAs, including noncoding RNAs (ncRNAs). However, the functional relevance of EV-derived ncRNAs in tumor angiogenesis remains to be elucidated. In this review, we summarized current research progress on the biological functions and underlying mechanisms of EV-derived ncRNAs in tumor angiogenesis in various cancers. In addition, we comprehensively discussed the potential applications of EV-derived ncRNAs as cancer biomarkers and novel therapeutic targets to tailor anti-angiogenic therapy.

Exosome-derived noncoding RNAs: Function, mechanism, and application in tumor angiogenesis

Exosomes are extracellular vesicles released by various cell types that perform various biological functions, mainly mediating communication between different cells, especially those active in cancer. Noncoding RNAs (ncRNAs), of which there are many types, were recently identified as enriched and stable in the exocrine region and play various roles in the occurrence and progression of cancer. Abnormal angiogenesis has been confirmed to be related to human cancer. An increasing number of studies have shown that exosome-derived ncRNAs play an important role in tumor angiogenesis. In this review, we briefly outline the characteristics of exosomes, ncRNAs, and tumor angiogenesis. Then, the mechanism of the impact of exosome-derived ncRNAs on tumor angiogenesis is analyzed from various angles. In addition, we focus on the regulatory role of exosome-derived ncRNAs in angiogenesis in different types of cancer. Furthermore, we emphasize the potential role of exosome-derived ncRNAs as biomarkers in cancer diagnosis and prognosis and therapeutic targets in the treatment of tumors.

Irradiated cell-derived exosomes transmit essential molecules inducing radiotherapy resistance

Radio-resistance has always been a major obstacle in radiation therapy (RT) progress. Radiotherapy (RT) leads to changes in the contents of released exosomes. The researches have shown that irradiated cell-derived exosomes influence recipient cell proliferation, migration, cell cycle arrest and apoptosis. All evidence indicates that exosomes play a significant role in radio-resistance. In this review, we describe the potential role of exosomes in cancer. We summarize that the irradiated cell-derived exosomes influence radio-resistance in recipient cells by three main mechanisms: 1) enhancing DNA repair, 2) regulating cell death signalling pathways, 3) inducing cancer cells to exhibit stem cell properties. We also discuss that the origin of the phenomenon might be the changes of molecular mechanisms of irradiated cell-derived exosomes formation affected by RT. Further, targeting exosomes as an adjuvant therapy might be a promising way for cancer treatments.

Exosomes in Pathogenesis, Diagnosis, and Treatment of Hepatocellular Carcinoma

Exosomes are extracellular vesicles with a diameter of 30-150 nm that are released by most types of cells and have been confirmed to be involved in many physical and pathological processes, especially in cell to cell communication. Compared with other vesicles, exosomes have a unique double-layer saclike structure that allows them to be present stably in various body fluids, including blood, cerebrospinal fluid, urine, saliva, and serous cavity effusion. The cargoes of exosomes reflect the characteristics of host cells. Due to the nature of hepatocellular carcinoma (HCC) cells, heterogeneity in the bioactive substances usually exist in exosomes. In addition, exosomes can efficiently deliver cargoes to the target cells to exert pathological functions, playing important role in tumor occurrence, development, metastasis, immune regulation, and drug resistance. Previous studies have been shown that exosomes have wide applications in diagnosis and treatment of HCC. In this review, we discuss these recent findings and highlight the significant roles of exosomes in HCC, focusing on the effect and underlying mechanisms of exosomes to regulate HCC progression and the potential clinical value of exosomes as biomarkers and therapeutic targets.

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.

Role of Exosomes in Immune Microenvironment of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the most common primary liver cancer. Since most patients with HCC are diagnosed at the intermediate or advanced stage and because HCC has a high incidence of metastasis and recurrence, it is one of the leading causes of cancer death. Exosomes are a subtype of extracellular vesicles and are typically 30-150 nm in diameter. Originating from endosomes, they can be secreted by almost all living cells. They are widely present in various body fluids and serve as an important medium for the interactions between cells. A series of studies have revealed that exosomes-mediated intercellular transfer of proteins, nucleic acids, and metabolites plays a crucial role in the initiation and progression of HCC, hypoxia and angiogenesis, chemotherapy sensitivity, and cell death mode and regulates the immune microenvironment. In this paper, we reviewed the recent researches on the multiple roles of tumor-associated exosomes in the progression of HCC. We laid particular focus on those researches that reveal how exosomes regulate the tumor immune microenvironment (TIME) and how exosomal cargos affect the progression of HCC. Besides, we emphasize some prospective directions to achieve a more accurate and complete analysis of the HCC immune microenvironment.

The Role of Small Extracellular Vesicles in the Progression of Colorectal Cancer and Its Clinical Applications

Colorectal cancer (CRC) is one of the most common cancers worldwide and a longstanding critical challenge for public health. Screening has been suggested to effectively reduce both the incidence and mortality of CRC. However, the drawback of the current screening modalities, both stool-based tests and colonoscopies, is limited screening adherence, which reduces the effectiveness of CRC screening. Blood tests are more acceptable than stool tests or colonoscopy as a first-line screening approach. Therefore, identifying blood biomarkers for detecting CRC and its precancerous neoplasms is urgently needed to fulfill the unmet clinical need. Currently, many kinds of blood contents, such as circulating tumor cells, circulating tumor nucleic acids, and extracellular vesicles, have been investigated as biomarkers for CRC detection. Among these, small extracellular vesicles (sEVs) have been demonstrated to detect CRC effectively in recent reports. sEVs enable intercellular shuttling-for instance, trafficking between recipient cancer cells and stromal cells-which can affect tumor initiation, proliferation, angiogenesis, immune regulation; metastasis, the cancer-specific molecules, such as proteins, microRNAs, long noncoding RNAs, and circular RNAs, loaded into cancer-derived sEVs may serve as biomarkers for the detection of cancers, including CRC. Indeed, accumulating evidence has shown that nucleic acids and proteins contained in CRC-derived sEVs are effective as blood biomarkers for CRC detection. However, investigations of the performance of sEVs for diagnosing CRC in clinical trials remains limited. Thus, the effectiveness of sEV biomarkers for diagnosing CRC needs further validation in clinical trials.

Exosomes as potential diagnosis and treatment for liver cancer

BACKGROUND

Liver cancer is the fourth most significant cause of cancer-related death. Lack of early diagnosis strategy and a scarcity of efficient therapy constitute the main reasons for its lethality. Exosomes, which contain various bioactive molecules, are characterized by high biocompatibility, low immunogenicity, and high transport efficiency. As a result, exosomes have become a research hotspot and present significant potential for cancer diagnosis biomarkers, biotherapeutics, therapy targets, drug carriers and therapeutic agents.

AIM

To explore the potential of exosomes in the diagnosis and treatment of liver cancer.

METHODS

We conducted a systematic literature search via PubMed and Web of Science. The following keywords were used: "exosomal biomarkers", "exosomal therapy", "exosomal therapy", and "liver cancer" or "HCC". The duplicate data were deleted by EndNote software. Literature search focused on full-texts and references of each article were carefully checked. One author (Xiao-Cui Wei) screened the literature that met the following inclusion criteria: (1) Detection of exosomes or their contents in clinical samples (body fluid or tissue); or (2) Exosomes served as drug carriers or therapeutic factors. Two authors (Xiao-Cui Wei and Li-Juan Liu) independently reviewed all retained literature and analyzed the information.

RESULTS

A total of 1295 studies were identified using the systematic literature search. Of these, 835 duplicate studies were removed. A further 402 irrelevant studies were excluded due to being irrelevant, including other diseases, review articles, the literature containing neither clinical samples nor animal experiments, exosome-independent studies, methods for detecting exosomes, or articles in Chinese. Finally, 58 published papers were retained and analyzed in the study. It showed a list of potential exosomal biomarkers that were upregulated in the blood samples of patients with liver cancer. Those downregulated in exosomes might serve as possible biotherapeutics. Some exosomes derived from cells in vitro were used for cytology or animal experiments to explore the mechanism of these exosome contents in disease. These contents might serve as potential targets for liver cancer. Additionally, we also discussed that exosomes serve as drug carriers or therapeutic factors.

CONCLUSION

Exosomes might serve as potential biomarkers or therapeutic biotargets in liver cancer and have the potential to act as drug carriers and self-treatment factors for liver cancer patients.

Hepatitis B core antigen modulates exosomal miR-135a to target vesicle-associated membrane protein 2 promoting chemoresistance in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors. The association of hepatitis B virus (HBV) infection with HCC is hitherto documented. Exosomal miRNAs contribute to cancer progression and chemoresistance. HBV X protein has been known to modulate miRNAs that facilitate cell proliferation and the process of hepatocarcinogenesis. However, there has been no report on hepatitis B core antigen (HBc) regulating exosomal miRNAs to induce drug resistance of HCC cells.

AIM

To elucidate the mechanism by which HBc promotes Doxorubicin hydrochloride (Dox) resistance in HCC.

METHODS

Exosomes were isolated by ultracentrifugation. The morphology and size of exosomes were evaluated by Dynamic Light Scattering (DLS) and transmission electron microscopy (TEM). The miRNAs differentially expressed in HCC were identified using The Cancer Genome Atlas (TCGA) database. The level of miR-135a-5p in patient tissue samples was detected by quantitative polymerase chain reaction. TargetScan and luciferase assay were used to predict and prove the target gene of miR-135a-5p. Finally, we identified the effects of miR-135a-5p on anti-apoptosis and the proliferation of HCC in the presence or absence of Dox using flow cytometry, Cell counting kit 8 (CCK-8) assay and western blot.

RESULTS

We found that HBc increased the expression of exosomal miR-135a-5p. Integrated analysis of bioinformatics and patient samples found that miR-135a-5p was increased in HCC tissues in comparison with paracancerous tissues. Bioinformatic analysis and in vitro validation identified vesicle-associated membrane protein 2 (VAMP2) as a novel target gene of miR-135a-5p. Functional assays showed that exosomal miR-135a-5p induced apoptosis protection, cell proliferation, and chemotherapy resistance in HCC. In addition, the rescue experiment demonstrated that VAMP2 reversed apoptosis protection, cell growth, and drug resistance by miR-135a-5p. Finally, HBc promoted HCC anti-apoptosis, proliferation, and drug resistance and prevented Dox-induced apoptosis via the miR-135a-5p/VAMP2 axis.

CONCLUSION

These data suggested that HBc upregulated the expression of exosomal miR-135a-5p and promoted anti-apoptosis, cell proliferation, and chemical resistance through miR-135a-5p/VAMP2. Thus, our work indicated an essential role of the miR-135a-5p/VAMP2 regulatory axis in chemotherapy resistance of HCC and a potential molecular therapeutic target for HCC.

Autophagy and ncRNAs: Dangerous Liaisons in the Crosstalk between the Tumor and Its Microenvironment

Simple Summary

Tumor cells communicate with the stromal cells within the tumor microenvironment (TME) to create a conducive environment for tumor growth. One major avenue for mediating crosstalk between various cell types in the TME involves exchanges of molecular payloads in the form of extracellular vesicles/exosomes. Autophagy is a fundamental mechanism to maintain intracellular homeostasis but recent reports suggest that secretory autophagy plays an important role in promoting secretion of exosomes that are packaged with non-coding RNAs (ncRNAs) and other biomolecules from the donor cell. Uptake of exosomal autophagy-modulating ncRNAs by recipient cells may further perpetuate tumor progression.

Abstract

Autophagy is a fundamental cellular homeostasis mechanism known to play multifaceted roles in the natural history of cancers over time. It has recently been shown that autophagy also mediates the crosstalk between the tumor and its microenvironment by promoting the export of molecular payloads such as non-coding RNA (ncRNAs) via LC3-dependent Extracellular Vesicle loading and secretion (LDELS). In turn, the dynamic exchange of exosomal ncRNAs regulate autophagic responses in the recipient cells within the tumor microenvironment (TME), for both tumor and stromal cells. Autophagy-dependent phenotypic changes in the recipient cells further enhance tumor growth and metastasis, through diverse biological processes, including nutrient supplementation, immune evasion, angiogenesis, and therapeutic resistance. In this review, we discuss how the feedforward autophagy-ncRNA axis orchestrates vital communications between various cell types within the TME ecosystem to promote cancer progression.

The role of AKR1 family in tamoxifen resistant invasive lobular breast cancer based on data mining

Background

Tamoxifen (TAM) resistance to invasive lobular cell carcinoma is a challenge for breast cancer treatment. This study explored the role of Aldo-keto reductase family 1 (AKR1) family in tamoxifen-resistant aggressive lobular breast cancer based on data mining.

Methods

TAM-resistant invasive lobular breast cancer gene chip was downloaded from the Gene Expression Omnibus (GEO) database (accession-numbered as GSE96670). The online analytical tool GEO2R was used to screen for differentially expressed genes in TAM-resistant invasive lobular breast cancer cells and TAM-sensitive counterparts. A protein-protein interaction (PPI) networks were constructed using the STRING online platform and the Cytoscape software. GeneMANIA and GSCALite online tools were used to reveal the potential role of these hub genes in breast cancer progression and TAM resistance development. And the used the GSE67916 microarray data set to verify the differentially expression of these hub genes in breast cancer. The protein expression levels of AKR1C1, AKR1C2 and AKR1C3 in TAM-sensitive and resistant breast cancer cells were compared. The TAM sensitivity of breast cancer cells with or without AKR1C1, AKR1C2 or AKR1C3 gene manipulation was evaluated by cell viability assay.

Results

A total of 184 differentially expressed genes were screened. Compared with TAM sensitive breast cancer cells, 162 were up-regulated and 22 were down-regulated. The study identified several hub genes in the PPI network that may be involved in the development of TAM resistance of breast cancer, including signal transducer and activator of transcription 1 (STAT1), estrogen receptor alpha (ESR1), fibronectin1 (FN1), cytochrome P4501B1 (CYP1B1), AKR1C1, AKR1C2, AKR1C3 and uridine diphosphate glucuronosyltransferase (UGT) 1A family genes (UGT1A1, UGT1A3, UGT1A4, UGT1A6, UGT1A7, UGT1A8, UGT1A9, UGT1A10). Compared with TAM-sensitive counterparts, the expression levels of AKR1C1, AKR1C2, and AKR1C3 were up-regulated in TAM-resistant breast cancer cells.

Conclusions

Overexpression of each of these three genes significantly increased the resistance of breast cancer cells to TAM treatment, while their knockdown showed opposite effects, indicating that they are potential therapeutic target for the treatment of TAM-resistant breast cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-09040-8.

Exosomal microRNA-107 reverses chemotherapeutic drug resistance of gastric cancer cells through HMGA2/mTOR/P-gp pathway

Background

RNA cargo in exosomes, especially microRNAs (miRNAs), play an important role in the chemotherapy drug resistance of human cancers. However, the role and mechanism of exosomal miR-107 on multidrug resistance of gastric cancer cells was still not clear. In this study, we sought to explore whether exosomal miR-107 could reverse the resistance of gastric cancer cells to the chemotherapy drugs.

Methods

We extracted exosomes from sensitive (SGC-7901, MGC-803) and resistant (SGC-7901/5-FU) gastric cancer cells by ultracentrifugation and the isolated exosomes were identified using transmission electron microscopy (TEM) and dynamic light scattering analysis (DLS). The expression of miR-107 and high mobility group A2 (HMGA2) were detected by real-time quantitative PCR (RT-qPCR). MTT assay was used to investigate the effect of exosomes on gastric cancer cells growth in vitro. The uptake of exosomes by recipient cells were observed using a fluorescence microscope. The predicted target relationship between miR-107 and HMGA2 was verified by gauss-luciferase reporter assay. The expression of HMGA2, p-mTOR/mTOR, P-gp and other exosomal indicated marker proteins was detected by western blot.

Results

Our results indicated that the isolated exosomes were typically cup-like lipid bilayer membranes structure. SGC-7901/5-FU cells were cross-resistant to chemotherapy drug cisplatin (CDDP), and the sensitive cells-secreted exosomes drastically reversed the resistance of the resistant GC cells to the chemotherapeutic drugs, which was verified by exosomal inhibitor GW4896. Mechanistically, the reversal effect was mainly mediated by exosome-secreted miR-107 through downregulating the expression of target molecular HMGA2 and inhibiting HMGA2/mTOR/P-gp pathway, which were supported by results from luciferase reporter assay and rescue assay.

Conclusions

These findings demonstrated that exosome-transmitted miR-107 significantly enhanced the sensitivity of resistant gastric cancer cells to chemotherapeutic agents by mediating the HMGA2/mTOR/P-gp axis and exosomal miR-107 may be a novel target in gastric cancers treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-09020-y.

Gastrointestinal cancer drug resistance: the role of exosomal miRNAs

Resistance of gastrointestinal (GI) cancer cells to therapeutic agents are one of the major problems in treating this type of cancer. Although the exact mechanism of drug resistance has not yet been fully elucidated, various factors have been identified as contributing factors involved in this process. Several studies have revealed the role of exosomes, especially exosomal microRNAs (miRNAs), in GI tumorigenesis, invasion, angiogenesis, and drug resistance. Exosomes, a type of small extracellular vesicles (EVs), are originated from endosomes and are released into the extracellular environment and body fluids by different cell types. Exosomes mediate cell-cell communication by transferring different cargos, including miRNAs, between parent and recipient cells. Therefore, identifying these exosomal miRNAs and their functions in GI cancers might provide new clues to further explore the secret of this process and thus help in drug-resistance management. This review article will discuss the roles of exosomal miRNAs and their mechanisms of action in drug resistance of different types of GI cancer cells (e.g., stomach, esophagus, liver, pancreas, and colon) to therapeutic agents.

The Emerging Role of Exosomes in Cancer Chemoresistance

Chemoresistance is an impending challenge in cancer treatment. In recent years, exosomes, a subtype of extracellular vesicles with a diameter of 40-150 nm in bloodstream and other bio-fluids, have attracted increasing interest. Exosomes contain proteins, nucleic acids, and lipids, which act as important signaling molecules. Many reports indicate that exosomes play critical roles in chemoresistance through intercellular interactions, including drug removal from cells, transfer of drug resistance phenotypes to other cancer cells, and the increase in plastic stem cell subsets. Exosomes can reflect the physiological and pathological state of parent cells. Owing to their elevated stability, specificity, and sensitivity, exosomes are served as biomarkers in liquid biopsies to monitor cancer chemoresistance, progression, and recurrence. This review summarizes the exosome-mediated mechanisms of cancer chemoresistance, as well as its role in reversing and monitoring chemoresistance. The scientific and technological challenges and future applications of exosomes are also explored.

The multifaceted involvement of exosomes in tumor progression: Induction and inhibition

As key performers in intercellular communication, exosomes released by tumor cells play an important role in cancer development, including angiogenesis, cancer‐associated fibroblasts activation, epithelial‐mesenchymal transformation (EMT), immune escape, and pre‐metastatic niche formation. Meanwhile, other cells in tumor microenvironment (TME) can secrete exosomes and facilitate tumor progression. Elucidating mechanisms regarding these processes may offer perspectives for exosome‐based antitumor strategies. In this review, we mainly introduce the versatile roles of tumor or stromal cell derived exosomes in cancer development, with a particular focus on the biological capabilities and functionalities of their diverse contents, such as miRNAs, lncRNAs, and circRNAs. The potential clinical application of exosomes as biomarkers in cancer diagnosis and prognosis is also discussed. Finally, the current antitumor strategies based on exosomes in immunotherapy and targeted delivery for chemotherapeutic or biological agents are summarized.

Functional and Clinical Significance of Dysregulated microRNAs in Liver Cancer

Liver cancer is the leading cause of cancer-related mortality in the world. This mainly reflects the lack of early diagnosis tools and effective treatment methods. MicroRNAs (miRNAs) are a class of non-transcribed RNAs, some of which play important regulatory roles in liver cancer. Here, we discuss microRNAs with key impacts on liver cancer, such as miR-122, miR-21, miR-214, and miR-199. These microRNAs participate in various physiological regulatory pathways of liver cancer cells, and their modulation can have non-negligible effects in the treatment of liver cancer. We discuss whether these microRNAs can be used for better clinical diagnosis and/or drug development. With the advent of novel technologies, fast, inexpensive, and non-invasive RNA-based biomarker research has become a new mainstream approach. However, the clinical application of microRNA-based markers has been limited by the high sequence similarity among them and the potential for off-target problems. Therefore, researchers particularly value microRNAs that are specific to or have special functions in liver cancer. These include miR-122, which is specifically expressed in the liver, and miR-34, which is necessary for the replication of the hepatitis C virus in liver cancer. Clinical treatment drugs have been developed based on miR-34 and miR-122 (MRX34 and Miravirsen, respectively), but their side effects have not yet been overcome. Future research is needed to address these weaknesses and establish a feasible microRNA-based treatment strategy for liver cancer.

Transthyretin Suppressed Tumor Progression in Nonsmall Cell Lung Cancer by Inactivating MAPK/ERK Pathway

Background: Lung malignancy is a main source of disease passing all throughout the planet, whereas the transthyretin (TTR) is a specific biomarker for clinical diagnosis. However, its role in lung malignancy stays to be obscure. Materials and Methods: In the current examination, the authors made an endeavor to research impact of abnormal expression of TTR on nonsmall cell lung carcinoma (NSCLC) by overexpression or knockdown of TTR. To further explore the instruments' fundamental mechanism part of TTR in NSCLC, several signal pathways were searched and verified. To confirm the effect of TTR overexpression on tumors, in vivo experiments were conducted. Result: It was found that upregulated TTR clearly stifled cell proliferation, migration, invasion, and expanded apoptosis. Significant suppression of phosphor-extracellular signal-regulated kinase (ERK) was observed in TTR-treated NSCLC cells, implying that TTR was important for cellular progress by regulating mitogen-activated protein kinase/ERK signaling pathway. In in vivo experiment, overexpression of TTR promoted cell apoptosis and inhibited tumor growth. Conclusion: Overall, the results suggest that TTR has a potential antitumor effect in human NSCLC progression, which provides theoretical basis for the diagnosis and treatment of NSCLC. Above all, further understanding of TTR was useful for clinical care. Clinical Trial Registration Number: 2016-08.

Small molecules with huge impacts: the role of miRNA-regulated PI3K pathway in human malignancies

Along with evolution, a considerable number of signaling cascades have evolved within cells to meet their multifaceted needs. Among transmitting molecules, phosphoinositide 3-kinase (PI3K), Akt, and mammalian target of rapamycin (mTOR) have teamed up to build a signaling axis that effectively regulates various cellular processes including cell proliferation and migration. Given the extensive output of the PI3K/Akt/mTOR signaling axis, its aberrancy could subsequently lead to the formation of a wide range of human cancers spanning from hematologic malignancies to different types of solid tumors. Despite the high frequency of the PI3K pathway over-activation in most malignancies, mutations in the DNA sequence are not equally common. Such incompatibility sheds light on the possible effects of post-translational modification mechanisms that may take control of this pathway, some of the most important ones of which are through microRNAs (miRNAs or miRs). The present review is designed to take off the veil from the regulatory role of these small non-coding RNAs on the PI3K/Akt/mTOR signaling axis in carcinogenesis.

LHPP suppresses colorectal cancer cell migration and invasion in vitro and in vivo by inhibiting Smad3 phosphorylation in the TGF-β pathway

The roles of phospholysine phosphohistidine inorganic pyrophosphate phosphatase (LHPP) in tumorigenesis have been recently proven in hepatocellular carcinoma (HCC), cervical, pancreatic, bladder, and thyroid cancers. Previous research demonstrated that LHPP repressed cell proliferation and growth by inactivating the phosphatidylinositol 3-kinase/AKT signaling pathway in vitro and in vivo. However, the functions and potential mechanisms of LHPP as a tumor suppressor in colorectal cancer (CRC) metastasis are still unknown. Consequently, the Transwell assay and xenograft nude model showed that LHPP inhibited migration and invasion of CRC cells in vitro and in vivo, respectively. The expression of total and nuclear epithelial-to-mesenchymal transition (EMT)-related proteins were significantly reduced after LHPP upregulation. Human Gene Expression Array and IPA (Ingenuity Pathway Analysis) commercial software were applied to identify differentially expressed genes (DEGs) and potential cell signaling pathways. A total of 330 different genes were observed, including 177 upregulated genes and 153 downregulated genes. Bioinformatics analysis suggested that the transforming growth factor-β (TGF-β) signaling pathway was highly inactivated in this study. Then, Smad3 phosphorylation was apparently decreased, whereas Smad7 expression was markedly enhanced after upregulating LHPP expression. These results were proven once again after TGF-β1 stimulation. Furthermore, a specific inhibitor of Smad3 phosphorylation (SIS3) was applied to verify that LHPP repressed EMT of cancer cells by attenuating TGF-β/Smad signaling. The results suggested that suppression of the TGF-β/Smad signaling pathway by LHPP overexpression could be abolished by SIS3.

Exosomes: A New Pathway for Cancer Drug Resistance

Exosomes are extracellular vesicles (EVs) that are secreted into body fluids by multiple cell types and are enriched in bioactive molecules, although their exact contents depend on the cells of origin. Studies have shown that exosomes in the tumor microenvironment affect tumor growth, metastasis and drug resistance by mediating intercellular communication and the transport of specific molecules, although their exact mechanisms of action need to be investigated further. In this review, we have summarized current knowledge on the relationship between tumor drug resistance and exosomes, and have discussed the potential applications of exosomes as diagnostic biomarkers and therapeutic targets.

Extracellular Vesicle-Associated miRNAs and Chemoresistance: A Systematic Review

Simple Summary

There is an urgent need for a non-invasive, specific biomarker to identify patients at risk of chemoresistance, which it is the ability of cancer cells to escape the effect of chemotherapy drugs. Extracellular vesicles contain an abundance of miRNAs that demonstrate expression across a range of cancers including breast cancer, renal cell carcinoma, lung cancer, multiple myeloma, and lymphoma. Interestingly, miRNAs encapsulated within extracellular vesicles (EVs) including exosomes display an association with chemoresistance. Here, we performed a systematic revision to evaluate the association between miRNAs within EVs and chemotherapy resistance. The summarized graphical abstract indicates that several exosome-derived miRNAs involved in chemotherapy resistance can be found among different types of cancers, such as colorectal, ovarian, breast, and lung cancer, and lymphoma.

Abstract

Cancer is a leading public health issue globally, and diagnosis is often associated with poor outcomes and reduced patient survival. One of the major contributors to the fatality resultant of cancer is the development of resistance to chemotherapy, known as chemoresistance. Furthermore, there are limitations in our ability to identify patients that will respond to therapy, versus patients that will develop relapse, and display limited or no response to treatment. This often leads to patients being subjected to multiple futile treatment cycles, and results in a reduction in their quality of life. Therefore, there is an urgent clinical need to develop tools to identify patients at risk of chemoresistance, and recent literature has suggested that small extracellular vesicles, known as exosomes, may be a vital source of information. Extracellular vesicles (EV) are membrane bound vesicles, involved in cell-cell communication, through the transfer of their cargo, which includes proteins, lipids, and miRNAs. A defined exploration strategy was performed in this systematic review in order to provide a compilation of key EV miRNAs which may be predictive of chemoresistance. We searched the PubMed, Science Direct, and Scopus databases using the following keywords: Extracellular vesicles OR exosomes OR EVs AND miRNA AND Chemotherapy OR Chemoresistance OR Cancer Recurrence from 2010 to 2020. We found 31 articles that reported key EV-associated miRNAs involved in cancer recurrence related to chemoresistance. Interestingly, multiple studies of the same tumor type identified different microRNAs, and few studies identified the same ones. Specifically, miR-21, miR-222, and miR-155 displayed roles in response to chemotherapy, and were found to be common in colorectal cancer, ovarian cancer, breast cancer, and diffuse large B cell lymphoma patients (DLBCL). miR-21 and miR-222 were found to favour the development of chemoresistance, whereas miR-155 exhibited a contrasting role, depending on the type of primary tumor. Whilst high levels of miR-155 were found to correlate with chemotherapy resistance in DLBCL, it was found to be predictive of an effective response towards chemotherapy in breast cancer. Thus, further research regarding the roles of these miRNAs would be beneficial in terms of designing novel tools to counteract the progression of cancer in a not-to-distant future.