Role of exosomes in treatment of hepatocellular carcinoma

Immunotherapy for hepatocellular carcinoma: Recent advances and future targets

Immunotherapy is a promising approach to treating various types of cancers, including hepatocellular carcinoma (HCC). While single immunotherapy drugs show limited effectiveness on a small subset of patients, the combination of the anti PD-L1 atezolizumab and anti-vascular endothelial growth factor bevacizumab has shown significant improvement in survival compared to sorafenib as a first-line treatment. However, the current treatment options still have a low success rate of about 30%. Thus, more effective treatments for HCC are urgently required. Several novel immunotherapeutic methods, including the use of novel immune checkpoint inhibitors, innovative immune cell therapies like chimeric antigen receptor T cells (CAR-T), TCR gene-modified T cells and stem cells, as well as combination strategies are being tested in clinical trials for the treatment of HCC. However, some crucial issues still exist such as the presence of heterogeneous antigens in solid tumors, the immune-suppressive environment within tumors, the risk of on-target/off-tumor, infiltrating CAR-T cells, immunosuppressive checkpoint molecules, and cytokines. Overall, immunotherapy is on the brink of major advancements in the fight against HCC.

Exosome-mediated circTTLL5 transfer promotes hepatocellular carcinoma malignant progression through miR-136-5p/KIAA1522 axis

BACKGROUND

Exosomes have been recognized as messengers for intercellular communication in tumor microenvironment. Exosomal circRNAs are reported to be important in tumors. Here, this study identified the potential function of exosomal circular RNA tubulin tyrosine ligase like 5 (circTTLL5) in hepatocellular carcinoma (HCC) progression.

METHODS

The expression of circTTLL5, microRNA (miR)- 136-5p and KIAA1522 was detected using qRT-PCR and Western blot assays. Exosomes were isolated by ultracentrifugation, and qualified by transmission electron microscopy (TEM) and Western blot. Cell proliferation, apoptosis and metastasis were investigated using cell counting kit-8, colony formation, flow cytometry, would healing, transwell and Western blot assays, respectively. The interaction between miR-136-5p and circTTLL5 or KIAA1522 was confirmed by dual-luciferase reporter and pull-down assays. In vivo experiment was performed using Xenograft models.

RESULTS

CircTTLL5 was incorporated into exosomes and highly expressed in HCC tissues and cells. CircTTLL5 knockdown suppressed HCC cell proliferation and metastasis in vitro and impeded tumor growth in mice. CircTTLL5 could be delivered to recipient cells via exosomes, and treatment of circTTLL5-elevated exosomes could attenuate the anticancer effects of circTTLL5 knockdown on HCC in vitro and in vivo. Mechanically, circTTLL5 could sponge miR-136-5p, which controlled its down-stream target KIAA1522. MiR-136-5p inhibition reversed the effects of circTTLL5 knockdown on HCC cells. Besides that, miR-136-5p re-expression inhibited HCC cell growth and metastasis, which was abated by KIAA1522 overexpression.

CONCLUSION

Exosomal circTTLL5 promoted HCC progression through miR-136-5p/KIAA1522 axis, suggesting that blockage of the exosome-mediated transfer of circTTLL5 might be a therapeutic target for HCC.

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.

The Role of the NLRP3 Inflammasome in HCC Carcinogenesis and Treatment: Harnessing Innate Immunity

Simple Summary

The Hepatocellular Carcinoma (HCC) remains a major concern for the public health. The pandemic of metabolic syndrome in the Western societies and the considerable amounts of viral hepatitis in the underdeveloped countries keep fueling s the development of HCC. The hepatotropic viruses evade the NLRP3 inflammasome in order to sustain the chronicity of infection leading to cirrhosis while in the established tumors the activation of NLRP3 promotes several pro-tumorigenic effects. That leads to substantial economic burden for the societies and alternative therapeutic targets should be investigated. Reviewing past and more recent literature it can be deduced that the NLRP3 inflammasome could be an ideal therapeutic effects and it should be studied in more depth.

Abstract

The HCC constitutes one of the most frequent cancers, with a non-decreasing trend in disease mortality despite advances in systemic therapy and surgery. This trend is fueled by the rise of an obesity wave which is prominent the Western populations and has reshaped the etiologic landscape of HCC. Interest in the nucleotide-binding domain leucine-rich repeat containing (NLR) family member NLRP3 has recently been revived since it would appear that, by generating inflammasomes, it participates in several physiologic processes and its dysfunction leads to disease. The NLRP3 inflammasome has been studied in depth, and its influence in HCC pathogenesis has been extensively documented during the past quinquennial. Since inflammation comprises a major regulator of carcinogenesis, it is of paramount importance an attempt to evaluate the contribution of the NLRP3 inflammasome to the generation and management of HCC. The aim of this review was to examine the literature in order to determine the impact of the NLRP3 inflammasome on, and present a hypothesis about its input in, HCC.

Exosomes in the Treatment of Pancreatic Cancer: A Moonshot to PDAC Treatment?

Pancreatic Ductal Adenocarcinoma (PDAC) constitutes a leading cause of cancer death globally. Its mortality remains unaltered despite the considerable scientific progress made in the fields of diagnostics and treatment. Exosomes comprise of small extracellular vesicles secreted by nearly all cells; their cargo contains a vast array of biomolecules, such as proteins and microRNAs. It is currently established that their role as messengers is central to a plethora of both physiologic and pathologic processes. Accumulating data have shed light on their contributions to carcinogenesis, metastasis, and immunological response. Meanwhile, the advancement of personalized targeted therapies into everyday clinical practice necessitates the development of cost-efficient treatment approaches. The role of exosomes is currently being extensively investigated towards this direction. This review aims to summarize the current pre-clinical and clinical evidence regarding the effects of exosomal applications in the timely diagnosis, prognosis, and therapeutic management of pancreatic cancer.

Serum-derived exosomes function as tumor antigens in patients with advanced hepatocellular carcinoma

Exosomes are protein-containing vesicles that are secreted into the blood to mediate important biological and pathological processes. The present study enrolled 86 patients with advanced hepatocellular carcinoma (HCC) and 60 healthy controls. Serum exosome levels of the patient group were significantly elevated compared with the healthy control group (P = 0.001). No significant differences were observed between patients with serum alpha-fetoglobulin levels of less than 200 ng/mL and more than 200 ng/mL. In vitro, dendritic cells (DCs) were activated by exosomes and could promote T cell proliferation, exhibiting a killing effect on HepG2 cells. In addition, DCs loaded with tumor exosomes (DC-TEX) showed an antitumor effect in a subcutaneous tumor model. This study shows exosome levels in patients with HCC to be significantly higher than in healthy individuals. Furthermore, exosomes derived from serum of patients with advanced HCC function as tumor antigens.

Dairy consumption and hepatocellular carcinoma risk

This review provides epidemiological and translational evidence for milk and dairy intake as critical risk factors in the pathogenesis of hepatocellular carcinoma (HCC). Large epidemiological studies in the United States and Europe identified total dairy, milk and butter intake with the exception of yogurt as independent risk factors of HCC. Enhanced activity of mechanistic target of rapamycin complex 1 (mTORC1) is a hallmark of HCC promoted by hepatitis B virus (HBV) and hepatitis C virus (HCV). mTORC1 is also activated by milk protein-induced synthesis of hepatic insulin-like growth factor 1 (IGF-1) and branched-chain amino acids (BCAAs), abundant constituents of milk proteins. Over the last decades, annual milk protein-derived BCAA intake increased 3 to 5 times in Western countries. In synergy with HBV- and HCV-induced secretion of hepatocyte-derived exosomes enriched in microRNA-21 (miR-21) and miR-155, exosomes of pasteurized milk as well deliver these oncogenic miRs to the human liver. Thus, milk exosomes operate in a comparable fashion to HBV- or HCV- induced exosomes. Milk-derived miRs synergistically enhance IGF-1-AKT-mTORC1 signaling and promote mTORC1-dependent translation, a meaningful mechanism during the postnatal growth phase, but a long-term adverse effect promoting the development of HCC. Both, dietary BCAA abundance combined with oncogenic milk exosome exposure persistently overstimulate hepatic mTORC1. Chronic alcohol consumption as well as type 2 diabetes mellitus (T2DM), two HCC-related conditions, increase BCAA plasma levels. In HCC, mTORC1 is further hyperactivated due to RAB1 mutations as well as impaired hepatic BCAA catabolism, a metabolic hallmark of T2DM. The potential HCC-preventive effect of yogurt may be caused by lactobacilli-mediated degradation of BCAAs, inhibition of branched-chain α-ketoacid dehydrogenase kinase via production of intestinal medium-chain fatty acids as well as degradation of milk exosomes including their oncogenic miRs. A restriction of total animal protein intake realized by a vegetable-based diet is recommended for the prevention of HCC.

Diagnostic, Predictive and Prognostic Molecular Biomarkers in Pancreatic Cancer: An Overview for Clinicians

Simple Summary

Pancreatic cancer is the fourth most common cancer-related cause of death in the United States and is usually asymptomatic in early stages. There is a scarcity of tests that facilitate early diagnosis or accurately predict the disease progression. To this end, biomarkers have been identified as important tools in the diagnosis and management of pancreatic cancer. Despite the increasing number of biomarkers described in the literature, most of them have demonstrated moderate sensitivity and/or specificity and are far from being considered as screening tests. More efficient non-invasive biomarkers are needed to facilitate early-stage diagnosis and interventions. Multi-disciplinary collaboration might be required to facilitate the identification of such markers.

Abstract

Pancreatic ductal adenocarcinoma (PDAC) is the most common pancreatic malignancy and is associated with aggressive tumor behavior and poor prognosis. Most patients with PDAC present with an advanced disease stage and treatment-resistant tumors. The lack of noninvasive tests for PDAC diagnosis and survival prediction mandates the identification of novel biomarkers. The early identification of high-risk patients and patients with PDAC is of utmost importance. In addition, the identification of molecules that are associated with tumor biology, aggressiveness, and metastatic potential is crucial to predict survival and to provide patients with personalized treatment regimens. In this review, we summarize the current literature and focus on newer biomarkers, which are continuously added to the armamentarium of PDAC screening, predictive tools, and prognostic tools.

Prospects and challenges of extracellular vesicle-based drug delivery system: considering cell source

Extracellular vesicles (EVs), including exosomes, microvesicles, and apoptotic bodies, are nanosized membrane vesicles derived from most cell types. Carrying diverse biomolecules from their parent cells, EVs are important mediators of intercellular communication and thus play significant roles in physiological and pathological processes. Owing to their natural biogenesis process, EVs are generated with high biocompatibility, enhanced stability, and limited immunogenicity, which provide multiple advantages as drug delivery systems (DDSs) over traditional synthetic delivery vehicles. EVs have been reported to be used for the delivery of siRNAs, miRNAs, protein, small molecule drugs, nanoparticles, and CRISPR/Cas9 in the treatment of various diseases. As a natural drug delivery vectors, EVs can penetrate into the tissues and be bioengineered to enhance the targetability. Although EVs' characteristics make them ideal for drug delivery, EV-based drug delivery remains challenging, due to lack of standardized isolation and purification methods, limited drug loading efficiency, and insufficient clinical grade production. In this review, we summarized the current knowledge on the application of EVs as DDS from the perspective of different cell origin and weighted the advantages and bottlenecks of EV-based DDS.

Using Hepatocellular Carcinoma Tumor Burden Score to Stratify Prognosis after Liver Transplantation

Liver transplantation (LT) remains a mainstay of treatment for hepatocellular carcinoma (HCC). Tumor factors such as size and number of tumors define eligibility for LT using the Milan criteria. The tumor burden score (TBS) incorporates both tumor number and size into a single continuous variable and has been used to differentiate prognosis among patients undergoing resection for HCC. The objective of the present study was to evaluate the ability of the TBS to predict overall and recurrence-free survival in patients undergoing LT for HCC. The Scientific Registry of Transplant Recipients (SRTR) was used to analyze all liver transplants for HCC, with initial tumor size data from 2004 to 2018. There were 12,486 patients in the study period. In the unadjusted analyses, patients with a high TBS had worse overall (p < 0.0001) and recurrence-free (p < 0.0001) survival. In the adjusted analyses, a high TBS was associated with a greater hazard ratio (HR) of death (HR = 1.21; 95%CI, [1.13-1.30]; p < 0.001) and recurrence (HR = 1.49; 95%CI [1.3-1.7]; p < 0.001). When we superimposed the TBS on the Milan criteria, we saw that a higher TBS was associated with a higher hazard of recurrence at values that were either all within (HR = 1.20; 95%CI, [1.04-1.37]; p = 0.011) or variably within (HR = 1.53; 95%CI, [1.16-2.01]; p = 0.002) the Milan criteria. In conclusion, the TBS is a promising tool in predicting outcomes in patients with HCC after LT.

Application of peptides with an affinity for phospholipid membranes during the automated purification of extracellular vesicles

Extracellular vesicles (EVs), such as exosomes, have garnered increasing interest because of their potential clinical applications that range from diagnostics to therapeutics. The development of an automated and reproducible EV purification platform would therefore aid the introduction of EV biomarkers and therapies into the clinic. Here, we demonstrate that K8- as well as K-16 peptides (containing 8 and 16 lysine residues with dissociation constants of 102 nM and 11.6 nM for phosphatidylserine, respectively) immobilized on magnetic beads can capture small EVs (< 0.2 µm) from culture supernatants of MCF7 human breast cancer cells. Importantly, the bound EVs could be dissociated from the beads under mild conditions (e.g. 0.5 M NaCl), and the isolated EVs had the typical shapes of EVs under SEM and TEM with a mean particle size of 99 nm. Using the peptide-immobilized beads, we adapted a pre-existing bench top instrument for magnetic separation to perform automated EV purification with higher purity and yield than that obtained using the standard ultracentrifugation method.

Exosomal miR-638 Inhibits Hepatocellular Carcinoma Progression by Targeting SP1

Purpose

Exosomal microRNAs (miRNAs) play essential roles in the development of hepatocellular carcinoma (HCC). Nevertheless, the role and mechanism of exosomal miR-638 in HCC development remain largely unknown.

Methods

Exosomes were isolated and confirmed via transmission electron microscopy and western blot. The abundances of miR-638 and specificity protein 1 (SP1) were measured via quantitative reverse transcription polymerase chain reaction or western blot. Cell proliferation was investigated by Cell Counting Kit-8, colony formation assay, apoptosis, cell cycle distribution and related protein expression. Cell migration and invasion were detected via transwell assay and western blot. Co-culture experiment was performed to assess exosome transfer from HCC cells to endothelial cells. The target correlation between miR-638 and SP1 was analyzed via dual-luciferase reporter and RNA immunoprecipitation assays. The subcutaneous xenograft experiment was conducted to test the function of miR-638 in vivo.

Results

The miR-638 level declined in exosomes from serum or HCC cell medium. miR-638 overexpression repressed HCC cell proliferation by decreasing viability and colony formation and inducing apoptosis and cell cycle arrest at G1 phase, and decreased abilities of migration and invasion. Exosomal miR-638 from HCC cells could transfer to human umbilical vein endothelial cells (HUVECs) and suppress HUVEC proliferation, migration and invasion. SP1 was a target of miR-638 and overexpression of SP1 reversed the effect of miR-638 on HCC cells. Overexpression of miR-638 reduced xenograft tumor growth via decreasing SP1.

Conclusion

Exosomal miR-638 inhibited HCC tumorigenesis by targeting SP1. This study indicated the potential clinical implications of miR-638 in HCC.

Exosome-transmitted long non-coding RNA SENP3-EIF4A1 suppresses the progression of hepatocellular carcinoma

Extracellular communication mediated by exosomes in a tumor microenvironment can substantially affect tumor progression. However, the effect of exosomal long non-coding RNA SENP3-EIF4A1 on hepatocellular carcinoma (HCC) is still unclear. In this study, SENP3-EIF4A1 expressions in patients with HCC and healthy controls were detected and compared. Results showed that SENP3-EIF4A1 was significantly reduced in HCC tissues and exosomes from the plasma of patients with HCC (P<0.05) and was primarily encapsulated by exosomes. The patients with HCC and the healthy controls could be distinguished using exosomal SENP3-EIF4A1 (AUC=0.8028). The transfer of exosomal SENP3-EIF4A1 secreted by normal cells to HCC cells stimulated apoptosis and weakened the invasion and migration abilities of HCC cells to suppress their malignant biological behavior (P<0.05). Additionally, exosomal SENP3-EIF4A1 was capable of inhibiting tumor growth in vivo and modulating the expression of ZFP36 by competitively binding to miR-9-5p. In conclusion, exosomal SENP3-EIF4A1 is a new favorable biomarker for clinically detecting HCC, and SENP3-EIF4A1 can be transmitted by exosomes from normal cells to HCC cells to inhibit the in vitro and in vivo development of HCC. Thus, exosomal SENP3-EIF4A1 is involved in the communication between normal cells and HCC cells during the onset of HCC.

Serum exosomal long noncoding RNAs lnc-FAM72D-3 and lnc-EPC1-4 as diagnostic biomarkers for hepatocellular carcinoma

Long noncoding RNAs (lncRNAs), such as LINC00462, HOTAIR, and MALAT1, are significantly upregulated in hepatocellular carcinoma (HCC) tissues. However, lncRNA expression in the serum of HCC patients is still unclear. To identify candidate lncRNAs for HCC diagnosis, we purified exosomal total RNA from the serum of healthy volunteers (controls) and hepatitis, cirrhosis, and HCC patients. To assess the function of lncRNAs, small interfering RNAs and overexpression vectors were designed and cell viability and cell apoptosis assays conducted. The exosomes of the control group had a larger number of lncRNAs with a high amount of alternative splicing compared to hepatic disease patients. qPCR assays showed that lnc-FAM72D-3, lnc-GPR89B-15, lncZEB2-19, and lnc-EPC1-4 are differentially expressed in HCC. Furthermore, the expression level of lnc-EPC1-4 correlated with age. While the expression levels of lnc-GPR89B-15 and lnc-EPC1-4 correlated with serum alpha-fetoprotein level. lnc-FAM72D-3 knockdown decreased cell viability and promoted cell apoptosis, indicating that lnc-FAM72D-3 functions as an oncogene in HCC. In contrast, lnc-EPC1-4 overexpression inhibited cell proliferation and induced cell apoptosis, indicating that it functions as a tumor suppressor gene. Collectively, these findings show that lnc-FAM72D-3 and lnc-EPC1-4 play a novel role that might contribute to hepatocarcinogenesis and identify potential candidate biomarkers for HCC diagnosis.

Prognostic Value of Complement Component 2 and Its Correlation with Immune Infiltrates in Hepatocellular Carcinoma

Background

Single nucleotide polymorphism (SNP) of complement component 2 (C2) has been found to be significantly associated with hepatocellular carcinoma (HCC). However, little is known about the role and mechanism of C2 in HCC. In the present study, we aimed to explore the prognostic value of C2 and its correlation with tumor-infiltrating immune cells in HCC.

Materials and Methods

mRNA expression was downloaded from TCGA (365 HCC patients and 50 healthy controls), GSE14520 (220 HCC patients and 220 adjacent normal tissues), and ICGC HCC (232 HCC patients) cohorts. Unpaired Student's t-tests or ANOVA tests were used to evaluate differences of C2 expression. Univariate and multivariate analyses were used to analyze the prognostic value of C2. CIBERSORT was used to calculate the proportion of 22 kinds of tumor-infiltrating immune cells.

Results

Significantly lower C2 expression was found at HCC compared to healthy controls, and C2 was associated with TNM stages. Higher C2 expression was significantly associated with better prognosis, and multivariate analysis showed that C2 was also an independent factor for the prognosis of HCC. Moreover, elevated CD4 T cells were found at HCC patients with higher C2 expression while the higher proportion of macrophage M0 cells was found in HCC patients with lower C2 expression. KEGG analysis showed that “cell cycle,” “AMPK signaling pathway,” and “PPAR signaling pathway” were enriched in HCC patients with higher C2 expression.

Conclusion

C2 is a prognostic factor for HCC and may be used as a therapeutic target for future treatment of HCC.

Exosome-transmitted circular RNA hsa_circ_0051443 suppresses hepatocellular carcinoma progression

Extracellular communication in the tumor microenvironment is critical. Results of qRT-PCR show that circ-0051443 is significantly lower in the plasma exosomes and tissues from patients with hepatocellular carcinoma (HCC) than healthy controls. Compared with the producer cells, circ-0051443 is mainly packaged into exosomes. A receiver operating characteristic curve (ROC) shows that the patients with HCC can be distinguished from the controls by exosomal circ-0051443. The role of exosomal circ-0051443 in HCC was determined by animal and cell analyses. Circ-0051443 is transmitted from normal cells to HCC cells via exosomes and suppresses the malignant biological behaviors by promoting cell apoptosis and arresting the cell cycle. Exosomal circ-0051443 decreases the weight and volume of the xenograft tumors in nude mice via BAK1 upregulation in these tumors. BAK1 expression is mediated by exosomal circ-0051443 through competitive bound to miR-331-3p. Therefore, exosomal circ-0051443 can serve as a predictor and potential therapeutic target for HCC.

Exosomes in sarcomas: Tiny messengers with broad implications in diagnosis, surveillance, prognosis and treatment

Exosomes are cell-secreted extracellular vesicles, which contain an array of biomolecules, such as proteins, mRNAs, microRNAs, and lipids, take part in intercellular communication and mediate tumor-host interactions. They are increasingly considered as a source of biomarkers for liquid biopsies as well as potential drug vectors. Sarcomas are rare malignant mesenchymal tumours and due to their relative rarity exosomes have not been investigated in as extensively as in epithelial malignancies. Nonetheless, valuable information has been gathered over the last years on the roles of exosomes in sarcomas. In the present review we summarize all relevant data obtained so far from cell lines, animal models and patients with emphasis on their potential clinical utility.

Recent progress in the emerging role of exosome in hepatocellular carcinoma

Exosomes are small membrane vesicles 50-150 nm in diameter released by a variety of cells, which contain miRNAs, mRNAs and proteins with the potential to regulate signalling pathways in recipient cells. Exosomes deliver nucleic acids and proteins to participate in orchestrating cell-cell communication and microenvironment modulation. In this review, we summarize recent progress in our understanding of the role of exosomes in hepatocellular carcinoma (HCC). This review focuses on recent studies on HCC exosomes, considering biogenesis, cargo and their effects on the development and progression of HCC, including chemoresistance, epithelial-mesenchymal transition, angiogenesis, metastasis and immune response. Finally, we discuss the clinical application of exosomes as a therapeutic agent for HCC.

The utility of serum exosomal microRNAs in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common types of cancer worldwide and the third most common cause of cancer-associated deaths each year. Due to the invasive, fast growth and insidious onset of HCC, most patients are diagnosed at an advanced stage, reducing the effectiveness of radical surgery. Therefore, effective early detection and diagnostic methods are crucial for improving the treatment and prognosis of HCC patients. Exosomes are 40- to 100-nm-sized vesicles that are released from many cell types into the extracellular space, and extensive evidence has suggested that exosomes are involved in the occurrence and development of HCC. Recently, the presence of microRNAs (miRNAs) in exosomes has been verified. Such miRNAs can be internalized by neighboring or distant cells to subsequently regulate multiple target genes in recipient cells at the posttranscriptional level and affect the processes of cell proliferation, differentiation and apoptosis. Herein, we summarize the current knowledge about the potential utility of serum exosomal miRNAs in the diagnosis and treatment of HCC.

Synovial fluid-derived exosomal lncRNA PCGEM1 as biomarker for the different stages of osteoarthritis

OBJECTS

The purpose of this study is to investigate the role of exosomal lncRNAs from plasma and from synovial fluid in patients with osteoarthritis (OA) and to determine their diagnostic value in distinguishing the early stage of OA from progressive stage of OA.

METHODS

Participants were divided into three groups. The control  group included 20 pre-arthritic patients, early OA group included 20 patients in the early OA, and late-stage OA group included 22 patients in the late-stage OA. For all subjects, blood sample from cubital vein and synovial fluid sample from knee joint were collected. Exosomes were extracted by ultracentrifugation. LncRNAs were extracted from exosomes using RNeasy kit, and the expression of several exosomal lncRNAs, including HOTAIR, PCGEM1, and GAS5, was measured using quantitative real-time polymerase chain reaction (qPCR). Also, Spearman's correlation test was performed to determine the correlation between exosomal lncRNA PCGEM1 and WOMAC index. Last, the receiver operating characteristic (ROC) curve was performed to determine the diagnostic value of exosomal lncRNA PCGEM1 in distinguishing the different stages of OA.

RESULTS

First, for plasma, both the expression of exosomes in three groups and the relative expression of exosomal lncRNAs chosen showed no significant difference among three groups, while for synovial fluid sample, the expression of exosomes in early OA and late-stage OA was much markedly higher than that in controls; and the expression of exosomal lncRNA PCGEM1 was markedly higher in late-stage OA than in early OA, and markedly higher in early OA than controls. Both the expression of exosomal lncRNA HOTAIR and GAS5 showed no significant difference among these groups. Second, there was a positive relationship between exosomal lncRNA PCGEM1 and WOMAC Index. Last, ROC curve showed that the area values under the curve of exosomal lncRNA PCGEM1 were 0.879, 0.757, and 0.593, respectively.

CONCLUSION

Our study demonstrated that exosomal lncRNA PCGEM1 might be a powerful indicator in distinguishing the early OA from the late-stage OA.

Serum and exosome long non coding RNAs as potential biomarkers for hepatocellular carcinoma

Background: Hepatocellular carcinoma (HCC) is one of the most aggressive cancers, with limited new diagnostic and therapeutic measures. This study aimed to investigate the utility of specific serum and exosome lncRNAs as biomarkers for early diagnosis of HCC.

Methods: The relative expression levels of eight selected lncRNAs in serum were evaluated by quantitative reverse transcription-PCR (qRT-PCR) in the training and validation sets of HCC patients and matched healthy controls. Additionally, the stability, specificity and diagnostic efficiency of these lncRNAs were evaluated to determine their potential as biomarkers. The levels of the final validated lncRNAs in exosome and urine samples of 15 HCC patients and 15 healthy controls were examined for source and path analysis.

Results: LINC00161 was significantly upregulated in serum samples of HCC patients and showed excellent stability and specificity (P< 0.001, fold change=2.85). The area under the receiver operating characteristic (ROC) curve of the validated lncRNA signature was 0.794 (95% CI, 0.712-0.877). LINC00161 expression was detected in serum exosome, exosome-free, and urine samples, and its levels in serum exosome were upregulated in patients with HCC as compared to controls (P= 0.011, fold change=4.27).

Conclusions: Our results indicated that circulating exosomal LINC00161 in serum may be a novel biomarker for HCC. LINC00161 is derived from exosomes into serum and may at least be partly metabolized through urine.

Exosomes in Pancreatic Cancer: from Early Detection to Treatment

BACKGROUND

Pancreatic cancer (PC) remains one of the most fatal forms of cancer worldwide with incidence nearly equal to mortality. This is often attributed to the fact that diagnosis is often not made until later disease stages when treatment proves difficult. Efforts have been made to reduce the mortality of PC through improvements in early screening techniques and treatments of late-stage disease. Exosomes, small extracellular vesicles involved in cellular communication, have shown promise in helping understand PC disease biology.

METHODS

In this review, we discuss current studies of the role of exosomes in PC physiology, and their potential use as diagnostic and treatment tools.

RESULTS

Exosomes have a role in diagnosing pancreatic cancer and in understanding tumor biology including migration, proliferation, chemoresistance, immunosuppression, cachexia and diabetes, and have a potential role in therapy for pancreatic cancer.

CONCLUSIONS

Exosomal analysis is beneficial in demonstrating mechanisms behind PC growth and metastasis, immunosuppression, drug resistance, and paraneoplastic conditions. Furthermore, the use of exosomes can be beneficial in detecting early-stage PC and exosomes have potential applications as therapeutic targets.

MicroRNA-6869-5p acts as a tumor suppressor via targeting TLR4/NF-κB signaling pathway in colorectal cancer

Many studies have implicated that microRNAs (miRNAs), as non-coding RNAs, play important roles in the development and progression of colorectal cancer (CRC). However, little is known about the role of a newly identified miRNA, miR-6869-5p, in CRC. We aim to investigate the modifying effects and underlying mechanisms of miR-6869-5 in colorectal carcinogenesis and progression. Significantly reduced levels of miR-6869-5p were observed in both serum exosomes tumor tissue samples from patients with CRC. The prediction of targets of miR-6869-5p in databases of targetscan, microRNA. ORG and miRDBA revealed that toll-like receptor 4 (TLR4) is a potential target for this miRNA. MiR-6869-5p could inhibit cell proliferation and the production of inflammatory cytokines (TNF-α and IL-6) in CRC cells via directly targeting TLR4. The protective effect of miR-6869-5p from colorectal carcinogenesis was dependent on TLR4/NF-κB signaling pathway. In addition, the 3-year survival was poor among CRC patients with decreased levels of miR-6869-5p in serum exosomes. Thus, miR-6869-5p may serve as a tumor suppressor in CRC, and serum exosomal miR-6869-5p is a promising circulating biomarker for the prediction of CRC prognosis.

Exosomes derived from cancerous and non-cancerous cells regulate the anti-tumor response in the tumor microenvironment

The tumor microenvironment (TME) is a unique platform of cancer biology that considers the local cellular environment in which a tumor exists. Increasing evidence points to the TME as crucial for either promoting immune tumor rejection or protecting the tumor. The TME includes surrounding blood vessels, the extracellular matrix (ECM), a variety of immune and regulatory cells, and signaling factors. Exosomes have emerged to be molecular contributors in cancer biology, and to modulate and affect the constituents of the TME. Exosomes are small (40-150 nm) membrane vesicles that are derived from an endocytic nature and are later excreted by cells. Depending on the cells from which they originate, exosomes can play a role in tumor suppression or tumor progression. Tumor-derived exosomes (TDEs) have their own unique phenotypic functions. Evidence points to TDEs as key players involved in tumor growth, tumorigenesis, angiogenesis, dysregulation of immune cells and immune escape, metastasis, and resistance to therapies, as well as in promoting anti-tumor response. General exosomes, TDEs, and their influence on the TME are an area of promising research that may provide potential biomarkers for therapy, potentiation of anti-tumor response, development of exosome-based vaccines, and exosome-derived nanocarriers for drugs.

Pathways of production and delivery of hepatocyte exosomes

Hepatocyte exosomes (Exo^Hep) are proposed to mediate physiological or pathophysiological signaling in a variety of hepatic target cells. Exo^Hep were purified from the medium of primary mouse hepatocytes or AML12 cells and characterized as ~100 nm nanovesicles that were positive for proteins commonly found in exosomes (CD9, CD81, flotillin) or hepatocytes (asialoglycoprotein receptor). Ethanol treatment of hepatocytes caused increased Exo^Hep release and increased cellular mRNA expression of components involved in intracellular vesicle trafficking (Rab 5a,b,c, Rab 7a, Rab 27a,b) or exosome biogenesis via the ESCRT (HGS, Alix, STAM1, TSG101, VTA1, YKT6) or ceramide (nSmase2) pathways. RNA interference of HGS, Alix, TSG101 or nSmase 2 caused exosome production by normal or ethanol-treated hepatocytes to be reduced. In mice, in vivo administration of fluorescently-labeled Exo^Hep resulted in their accumulation in the liver and preferential localization to hepatic stellate cells (HSC) or hepatocytes, the latter of which showed enhanced Exo^Hep binding when isolated from fibrotic mice. In cell co-cultures, the intercellular transfer of RNA from hepatocytes to hepatocytes or HSC was blocked by the exosome inhibitor GW4869. Exo^Hep binding to HSC or hepatocytes occurred via mechanisms that involved heparin-like molecules and cellular integrin αv or β1 subunits , and resulted in a reversal of fibrosis-associated gene expression in HSC and of ethanol-induced damage in hepatocytes. These studies provide insight regarding the regulation and/or participation of exosome biogenesis or trafficking components in hepatocytes and show that Exo^Hep can mediate therapeutic changes in activated HSC or injured hepatocytes that occur downstream of heparin- or integrin-dependent binding interactions.