Cancer Cell-derived Extracellular Vesicles Research Articles

Abstract 5441: Circulating exosomal microRNA-203 and microRNA-373 as non-invasive biomarkers for predicting prognosis and metastasis in human hepatocellular carcinoma

Abstract Background and Aim Hepatocellular carcinoma (HCC) is the fifth most common cancer and the most leading cause of cancer-related death worldwide. Although considerable progress has been made in treatment of HCC, early detection is still highly considered the key to improved survival. Thus, for the earlier diagnosis and accurate prediction of HCC, identification of non-invasive molecular biomarkers for HCC patients is an imperative need. Recently, cancer cell-derived extracellular vesicles (EVs) have been known to contain various intracellular biomolecules including microRNAs (miRNAs). The aim of this study was to evaluate whether exosomal miRNAs can serve as a serum-based biomarker in HCC. Materials and Methods We isolated exosome from serum samples from HCC patients as well as normal healthy controls using ultracentrifugation, and it was confirmed by expression of exosome markers (CD9, CD63, ALIX, and TSG101) based on immunoblotting. Next, the expression of 6 miRNAs (miRNA-24, -130a, -182, -203, -373, and -423) was analyzed in the exosome samples. We also investigated expression status of the 6 miRNAs in matched HCC tissues and corresponding normal liver tissues. MiRNAs expression was determined by quantitative real-time PCR (qRT-PCR), and miRNAs expression was normalized relative to cel-miR-39 and RNU6B expression for serum and tissue samples, respectively. Results We successfully purified exosome from serum clinical samples and detected miRNAs in the exosome. We observed that a subset of miRNAs from serum exosome, including miRNA-24, -130a, -182, -203, and -373 were enhanced in HCC patients than normal healthy controls. In further comparison between early stage and advanced stage of HCC patients, serum exosomal miRNA-203 (P<0.05) and miRNA-373 (P<0.05) were significantly up-regulated in advanced HCC patients. While no significant changes in the expression of other serum exosomal miRNAs (miRNA-24, -130a, -182, and -423) according to HCC progression. More interestingly, high serum exosomal miRNA-203 and miRNA-373 was associated with HCC progression (P<0.01) as well as prognosis (P<0.05) of HCC patients. Conclusions We provided the novel evidence for usefulness of serum circulating exosomal miR-203 and miR-373 expressions as strong potential biomarkers for predicting prognosis and metastasis of HCC patients. Citation Format: Gyeonghwa Kim, Eunhye Lee, Se Young Jang, Won Young Tak, Young Oh Kweon, Soo Young Park, Keun Hur. Circulating exosomal microRNA-203 and microRNA-373 as non-invasive biomarkers for predicting prognosis and metastasis in human hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5441. doi:10.1158/1538-7445.AM2017-5441

Abstract 783: Cancer cell-derived extracellular vesicles stimulate tumor angiogenesis by delivering VEGF to endothelial cells

Abstract Angiogenesis is essential for tumor growth and metastasis, and is orchestrated by a repertoire of growth factor signaling pathways that stimulate endothelial cell growth, migration and vessel formation. Recent studies have shown that angiogenesis can also be regulated by cell-derived extracellular vesicles. Exosomes are small endosomal-derived membrane vesicles that contain various biomolecules such as RNA and proteins, and are increasingly thought to play important roles in transferring informational cargo between cancer cells and stromal cells. In the majority of studies to date, the effects of cancer cell-derived exosomes have been attributed to their RNA cargo. In this study, we identified that exosomes derived from ovarian, colon and renal cancer cells contain abundant vascular endothelial growth factor (VEGF). Cancer cell-derived exosomes were found to activate the VEGF signaling pathway in endothelial cells and to stimulate endothelial cell migration and tube formation. Furthermore, our studies using inhibitors of VEGF signaling demonstrated that the stimulatory effects of cancer cell-derived exosomes on endothelial cells depend on the presence of VEGF in exosomes and are mediated via the VEGF signaling pathway. These findings indicate that cancer cell-derived exosomes promote tumor angiogenesis by delivering VEGF to endothelial cells. Citation Format: Song Yi Ko, Honami Naora. Cancer cell-derived extracellular vesicles stimulate tumor angiogenesis by delivering VEGF to endothelial cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 783. doi:10.1158/1538-7445.AM2017-783

MiR-21-5p in urinary extracellular vesicles is a novel biomarker of urothelial carcinoma.

BackgroundExtracellular vesicles are lipid bilayer vesicles containing protein, messengerRNA and microRNA. Cancer cell-derived extracellular vesicles may be diagnostic and therapeutic targets. We extracted extracellular vesicles from urine of urothelial carcinoma patients and the control group to identify cancer-specific microRNAs in urinary extracellular vesicles as new biomarkers.Materials and methodsmicroRNA from urinary extracellular vesicles extracted from 6 urothelial carcinoma patients and 3 healthy volunteers was analyzed. We verified candidate microRNAs in an independent cohort of 60 urinary extracellular vesicles samples. To normalize the microRNA expression level in extracellular vesicles, we examined the following in extracellular vesicles: protein concentration, CD9 intensity, amounts of whole miRNAs, RNA U6B small nuclear expression and the creatinine concentration of original urine correlating with the counts of extracted extracellular vesicles measured by the NanoSight™ system.RESULTSFrom the microarray results 5 microRNAs overexpressed in urinary extracellular vesicles of urothelial carcinoma patients were identified. Creatinine concentration of original urine correlated most with particle counts of extracellular vesicles, indicating that creatinine could be a new tool for normalizing microRNA expression. MiR-21-5p was the most potent biomarker in urinary extracellular vesicles (sensitivity, 75.0%; specificity, 95.8%) and was also overexpressed in urinary extracellular vesicles from urothelial carcinoma patients with negative urine cytology. For the subgroup with negative urine cytology, the sensitivity was 75.0% and specificity was 95.8%.ConclusionMiR-21-5p in urinary extracellular vesicles could be a new biomarker of urothelial carcinoma, especially for urothelial carcinoma patients with negative urine cytology.

Colorectal cancer cell-derived extracellular vesicles induce phenotypic alteration of T cells into tumor-growth supporting cells with transforming growth factor-β1-mediated suppression.

Emerging studies on tumor cell-derived extracellular vesicles (EVs) have shown the biological significance in tumor development and microenvironment through reprogramming immune cells around cancer cells. In this study, we used colorectal cancer cells as EVs donor, and T cells as recipients to examine whether EVs impair the T cell function. As a result, we found that colorectal cancer cell-derived EVs (CRC-EVs) were enriched with TGF-β1. Interestingly, CRC-EVs induced phenotypic alteration of the T cells to Treg-like cells through activating TGF-β/Smad signaling and inactivating SAPK signaling. Furthermore, the CRC-EVs-induced-Treg-like cells had a remarkable tumor-growth promoting activity in vitro and in vivo. These results suggest that colorectal cancer cells utilize EVs to tame immune cells for their prosperity.

Metabolic and Signaling Functions of Cancer Cell-Derived Extracellular Vesicles.

Extracellular vesicles have gained tremendous attention in the recent years as a novel mechanism of cell to cell communication. There are several types of extracellular vesicles, including exosomes, microvesicles, exosome, like vesicles, apoptotic bodies that differ mainly in the mechanism of biogenesis and secretion. The most well studied type of extracellular vesicles are the exosomes which are endosome-derived vesicles with a diameter of 50-150nm and enriched in ESCRT proteins including Alix, TSG101, Hsp70, and tetraspanins. It is now well established that exosomes promote tumor growth, alter the tumor microenvironment, facilitate the dissemination of cancer cells in an organotropic manner, modulate immune responses, and mediate resistance to therapy. Exosomes have also been recently implicated in an emerging hallmark of cancer, the cancer cell metabolism. The metabolic state of the cell defines, to a certain extent, both the rate of secretion and the molecular content of tumor-derived exosomes. Furthermore, exosomes have been shown to possess intrinsic metabolic activity since they can synthesize ATP by glycolysis. It follows that exosomes carry a number of metabolic enzymes and metabolites, including lactate, PGE, LDH isoforms, pyruvate, and monocarboxylate transporters. Last but not the least, exosomes are implicated in fatty acid synthesis and cholesterol metabolism and are thought to be crucial for the transcellular metabolism procedure. Uptake of exosomes is thought to alter the intracellular metabolic state of the cell. In summary, we describe the state of the art on the role of metabolism in the secretion, uptake, and the biological effects of exosomes in the metabolism of recipient cells.

Identification of EDIL3 on extracellular vesicles involved in breast cancer cell invasion

Cancer cell-derived extracellular vesicles have been linked to the pathogenesis of various cancers; however, the role of extracellular vesicles in tumorigenesis remains unclear. To identify extracellular vesicle proteins involved in cancer metastasis, quantitative proteomic analyses were performed on extracellular vesicles derived from two representative breast cancer cell lines: the less invasive MCF-7 and the invasive MDA-MB-231. Proteomic analysis allowed for the identification of 270 proteins in the extracellular vesicles. Here we report a new function of EDIL3 on extracellular vesicles, which are sufficient for enhancement of cell invasion and for acceleration of lung metastasis in vivo. This invasion is most likely mediated via the integrin-FAK signaling cascade in breast cancer cells. However, these effects are suppressed when EDIL3 is inactivated, providing evidence for a critical role of EDIL3 in development of cancer. Consistently, in human patients with metastatic breast cancer, the levels of EDIL3 on circulating extracellular vesicles are significantly elevated. This information is a remarkable breakthrough in understanding of the molecular mechanism underlying metastasis of breast cancer as well as in the research for cancer biomarkers using circulating extracellular vesicles. Furthermore, targeting EDIL3 on extracellular vesicles may lead to a new therapeutic option for treatment of breast cancer.

Targeting Functionality of Cancer Cell-Derived Extra cellular vesicles to Immune Cells of the Tumor Microenvironment

In most cases, cancer cells cannot proliferate alone. They receive support form stromal cells and recruit and reprogram non-malignant immune cells not to damage the cancer cells but to support the tumor growth. Classical Hodgkin lymphoma (cHL) is a good example, as its growth critically depends on tumor-supporting immune cells. The affected lymphoid tissue contains very few disseminated malignant Hodgkin- and Reed-Sternberg (H-RS) cells, which are outnumbered by a massive infiltrate of lymphocytes, fibroblasts and innate immune cells. [1]. The H-RS cells need this environment to survive and proliferate because they are usually not detectable in the peripheral blood and they have difficulties to grow in immune-deficient mice [2]. H-RS cells manipulate the bystander cells for better development of their malignant phenotype and evasion of the host defense [3]. Among the infiltrated immune cells, the eosinophils and mast cells play an important role and their cell count indicates a negative prognostic feature [4,5]. In vitro, the direct interaction with cancer cells communicates survival in cancer cells and the production of cancersupporting factors in immune cells. In the last years, extracellular vesicles (EVs) emerged as important vehicles to shuttle between different the cell types and communicate as a surrogate cellular crosstalk in trans [6,7].

Cavin-1/PTRF alters prostate cancer cell-derived extracellular vesicle content and internalization to attenuate extracellular vesicle-mediated osteoclastogenesis and osteoblast proliferation

BackgroundTumour-derived extracellular vesicles (EVs) play a role in tumour progression; however, the spectrum of molecular mechanisms regulating EV secretion and cargo selection remain to be fully elucidated. We have reported that cavin-1 expression in prostate cancer PC3 cells reduced the abundance of a subset of EV proteins, concomitant with reduced xenograft tumour growth and metastasis.MethodsWe examined the functional outcomes and mechanisms of cavin-1 expression on PC3-derived EVs (PC3-EVs).ResultsPC3-EVs were internalized by osteoclast precursor RAW264.7 cells and primary human osteoblasts (hOBs) in vitro, stimulating osteoclastogenesis 37-fold and hOB proliferation 1.5-fold, respectively. Strikingly, EVs derived from cavin-1-expressing PC3 cells (cavin-1-PC3-EVs) failed to induce multinucleate osteoblasts or hOB proliferation. Cavin-1 was not detected in EVs, indicating an indirect mechanism of action. EV morphology, size and quantity were also not affected by cavin-1 expression, suggesting that cavin-1 modulated EV cargo recruitment rather than release. While cavin-1-EVs had no osteoclastogenic function, they were internalized by RAW264.7 cells but at a reduced efficiency compared to control EVs. EV surface proteins are required for internalization of PC3-EVs by RAW264.7 cells, as proteinase K treatment abolished uptake of both control and cavin-1-PC3-EVs. Removal of sialic acid modifications by neuraminidase treatment increased the amount of control PC3-EVs internalized by RAW264.7 cells, without affecting cavin-1-PC3-EVs. This suggests that cavin-1 expression altered the glycosylation modifications on PC3-EV surface. Finally, cavin-1 expression did not affect EV in vivo tissue targeting as both control and cavin-1-PC3-EVs were predominantly retained in the lung and bone 24 hours after injection into mice.DiscussionTaken together, our results reveal a novel pathway for EV cargo sorting, and highlight the potential of utilizing cavin-1-mediated pathways to attenuate metastatic prostate cancer.

Circulating Extracellular Vesicles in Cancer Diagnosis and Monitoring

Mammalian cells, including cancer cells, secrete extracellular vesicles. These vesicles are nanosized, bilayered proteolipids with diameters of 50-1,000nm. It has been suggested that cancer cell-derived extracellular vesicles play diverse roles in cancer progression, which involve invasion, immune modulation, neovascularization, and metastasis. Moreover, their serum levels are significantly elevated in cancer patients compared with normal controls. Recent high-throughput proteomic and transcriptomic studies of these complex extracellular organelles have accelerated the discovery of cancer-specific biomarkers and the development of novel diagnostic tools based on extracellular vesicles. Although many vesicle-associated biomarker candidates have been reported for various types of cancer, few have been validated for clinical use due to preanalytical, technical, temporal, and financial problems. Here, we discuss the potential of extracellular vesicles as sources of biomarkers for cancer diagnosis and monitoring, as well as the limitations and obstacles to adoption of extracellular vesicle-based diagnosis.