Extracellular vesicle-mediated phenotype switching in malignant and non-malignant colon cells

Extracellular Vesicles in Colorectal Cancer: From Tumor Growth and Metastasis to Biomarkers and Nanomedications

Colorectal cancer (CRC) is a leading public health concern due to its incidence and high mortality rates, highlighting the requirement of an early diagnosis. Evaluation of circulating extracellular vesicles (EVs) might constitute a noninvasive and reliable approach for CRC detection and for patient follow-up because EVs display the molecular features of the cells they originate. EVs are released by almost all cell types and are mainly categorized as exosomes originating from exocytosis of intraluminal vesicles from multivesicular bodies, ectosomes resulting from outward budding of the plasma membrane and apoptotic bodies' ensuing cell shrinkage. These vesicles play a critical role in intercellular communications during physiological and pathological processes. They facilitate CRC progression and premetastatic niche formation, and they enable transfer of chemotherapy resistance to sensitive cells through the local or remote delivery of their lipid, nucleic acid and protein content. On another note, their stability in the bloodstream, their permeation in tissues and their sheltering of packaged material make engineered EVs suitable vectors for efficient delivery of tracers and therapeutic agents for tumor imaging or treatment. Here, we focus on the physiopathological role of EVs in CRCs, their value in the diagnosis and prognosis and ongoing investigations into therapeutic approaches.

Current Advances in Technologies for Single Extracellular Vesicle Analysis and Its Clinical Applications in Cancer Diagnosis

Extracellular vesicles (EVs) have been regarded as one of the most potential diagnostic biomarkers for different cancers, due to their unique physiological and pathological functions. However, it is still challenging to precisely analyze the contents and sources of EVs, due to their heterogeneity. Herein, we summarize the advances in technologies for a single EV analysis, which may provide new strategies to study the heterogeneity of EVs, as well as their cargo, more specifically. Furthermore, the applications of a single EV analysis on cancer early diagnosis are also discussed.

Liquid biopsy approaches and immunotherapy in colorectal cancer for precision medicine: Are we there yet?

Colorectal cancer (CRC) is the second leading cause of cancer-related deaths globally, with nearly half of patients detected in the advanced stages. This is due to the fact that symptoms associated with CRC often do not appear until the cancer has reached an advanced stage. This suggests that CRC is a cancer with a slow progression, making it curable and preventive if detected in its early stage. Therefore, there is an urgent clinical need to improve CRC early detection and personalize therapy for patients with this cancer. Recently, liquid biopsy as a non-invasive or nominally invasive approach has attracted considerable interest for its real-time disease monitoring capability through repeated sample analysis. Several studies in CRC have revealed the potential for liquid biopsy application in a real clinical setting using circulating RNA/miRNA, circulating tumor cells (CTCs), exosomes, etc. However, Liquid biopsy still remains a challenge since there are currently no promising results with high specificity and specificity that might be employed as optimal circulatory biomarkers. Therefore, in this review, we conferred the plausible role of less explored liquid biopsy components like mitochondrial DNA (mtDNA), organoid model of CTCs, and circulating cancer-associated fibroblasts (cCAFs); which may allow researchers to develop improved strategies to unravel unfulfilled clinical requirements in CRC patients. Moreover, we have also discussed immunotherapy approaches to improve the prognosis of MSI (Microsatellite Instability) CRC patients using neoantigens and immune cells in the tumor microenvironment (TME) as a liquid biopsy approach in detail.

Contribution of Tumor-Derived Extracellular Vesicles to Malignant Transformation of Normal Cells

Tumor-cell-derived extracellular vesicles (EVs) are known to carry biologically active molecules of parental cells, which can actively modulate the tumor microenvironment. EVs produced by tumor cells play significant roles in the development and maintenance of tumor growth, metastasis, immune escape, and other important processes. However, the ability of EVs to induce the transformation of normal cells has hardly been investigated. This review discusses studies that describe the ability of tumor-cell-derived EVs to alter the metabolism and morphology of normal cells, causing changes associated with malignant transformation. Additionally, the horizontal transfer of oncogenes through EVs of tumor cells and the induction of epigenetic changes in normal cells, which leads to genomic instability and subsequent oncogenic transformation of normal cells, are also discussed.

Fetuin-A Promotes 3-Dimensional Growth in LNCaP Prostate Cancer Cells by Sequestering Extracellular Vesicles to Their Surfaces to Act as Signaling Platforms

The present studies were conducted to evaluate key serum proteins and other components that mediate anchorage-independent growth (3-D growth) of LNCaP prostate cancer cells as spheroids. The cells were cultured on ultra-low attachment plates in the absence and presence of fetuin-A and with or without extracellular vesicles. The data show that fetuin-A (alpha 2HS glycoprotein) is the serum protein that mediates 3-D growth in these cells. It does so by sequestering extracellular vesicles of various sizes on the surfaces of rounded cells that grow as spheroids. These vesicles in turn transmit growth signals such as the activation of AKT and MAP kinases in a pattern that differs from the activation of these key growth signaling pathways in adherent and spread cells growing in 2-D. In the process of orchestrating the movement and disposition of extracellular vesicles on these cells, fetuin-A is readily internalized in adhered and spread cells but remains on the surfaces of non-adherent cells. Taken together, our studies suggest the presence of distinct signaling domains or scaffolding platforms on the surfaces of prostate tumor cells growing in 3-D compared to 2-D.

Extracellular Vesicles as Signal Carriers in Malignant Thyroid Tumors?

Extracellular vesicles (EVs) are small, membranous structures involved in intercellular communication. Here, we analyzed the effects of thyroid cancer-derived EVs on the properties of normal thyroid cells and cells contributing to the tumor microenvironment. EVs isolated from thyroid cancer cell lines (CGTH, FTC-133, 8505c, TPC-1 and BcPAP) were used for treatment of normal thyroid cells (NTHY), as well as monocytes and endothelial cells (HUVEC). EVs' size/number were analyzed by flow cytometry and confocal microscopy. Gene expression, protein level and localization were investigated by qRT-PCR, WB and ICC/IF, respectively. Proliferation, migration and tube formation were analyzed. When compared with NTHY, CGTH and BcPAP secreted significantly more EVs. Treatment of NTHY with cancer-derived EVs changed the expression of tetraspanin genes, but did not affect proliferation and migration. Cancer-derived EVs suppressed tube formation by endothelial cells and did not affect the phagocytic index of monocytes. The number of 6 μm size fraction of cancer-derived EVs correlated negatively with the CD63 and CD81 expression in NTHY cells, as well as positively with angiogenesis in vitro. Thyroid cancer-derived EVs can affect the expression of tetraspanins in normal thyroid cells. It is possible that 6 μm EVs contribute to the regulation of NTHY gene expression and angiogenesis.

State-of-the-Art: Exosomes in Colorectal Cancer

Colorectal cancer (CRC) has a high prevalence and mortality rate, globally. To date, the progression mechanisms of CRC are still elusive. Exosomes (~100 nm in diameter) correspond to a subset of extracellular vesicles formed by an array of cancerous cells and stromal cells. These particular nanovesicles carry and transmit bioactive molecules, like proteins, lipids, and genetic materials, which mediate the crosstalk between cancer cells and the microenvironment. Accumulating evidence has shown the decisive functions of exosomes in the development, metastasis, and therapy resistance of CRC. Furthermore, some recent studies have also revealed the abilities of exosomes to function as either biomarkers or therapeutic targets for CRC. This review focuses on the specific mechanisms of exosomes in regulating CRC progression, and summarizes the potential clinical applications of exosomes in the diagnosis and therapy of CRC.

Exploring the Inflammatory Pathogenesis of Colorectal Cancer

Colorectal cancer is one of the most commonly diagnosed cancers worldwide. Traditionally, mechanisms of colorectal cancer formation have focused on genetic alterations including chromosomal damage and microsatellite instability. In recent years, there has been a growing body of evidence supporting the role of inflammation in colorectal cancer formation. Multiple cytokines, immune cells such T cells and macrophages, and other immune mediators have been identified in pathways leading to the initiation, growth, and metastasis of colorectal cancer. Outside the previously explored mechanisms and pathways leading to colorectal cancer, initiatives have been shifted to further study the role of inflammation in pathogenesis. Inflammatory pathways have also been linked to some traditional risk factors of colorectal cancer such as obesity, smoking and diabetes, as well as more novel associations such as the gut microbiome, the gut mycobiome and exosomes. In this review, we will explore the roles of obesity and diet, smoking, diabetes, the microbiome, the mycobiome and exosomes in colorectal cancer, with a specific focus on the underlying inflammatory and metabolic pathways involved. We will also investigate how the study of colon cancer from an inflammatory background not only creates a more holistic and inclusive understanding of this disease, but also creates unique opportunities for prevention, early diagnosis and therapy.

Exosomes and Micro-RNAs in Aging Process

Exosomes are the main actors of intercellular communications and have gained great interest in the new cell-free regenerative medicine. These nanoparticles are secreted by almost all cell types and contain lipids, cytokines, growth factors, messenger RNA, and different non-coding RNA, especially micro-RNAs (mi-RNAs). Exosomes' cargo is released in the neighboring microenvironment but is also expected to act on distant tissues or organs. Different biological processes such as cell development, growth and repair, senescence, migration, immunomodulation, and aging, among others, are mediated by exosomes and principally exosome-derived mi-RNAs. Moreover, their therapeutic potential has been proved and reinforced by their use as biomarkers for disease diagnostics and progression. Evidence has increasingly shown that exosome-derived mi-RNAs are key regulators of age-related diseases, and their involvement in longevity is becoming a promising issue. For instance, mi-RNAs such as mi-RNA-21, mi-RNA-29, and mi-RNA-34 modulate tissue functionality and regeneration by targeting different tissues and involving different pathways but might also interfere with long life expectancy. Human mi-RNAs profiling is effectively related to the biological fluids that are reported differently between young and old individuals. However, their underlying mechanisms modulating cell senescence and aging are still not fully understood, and little was reported on the involvement of mi-RNAs in cell or tissue longevity. In this review, we summarize exosome biogenesis and mi-RNA synthesis and loading mechanism into exosomes' cargo. Additionally, we highlight the molecular mechanisms of exosomes and exosome-derived mi-RNA regulation in the different aging processes.

MiR-1-3p Suppresses Colorectal Cancer Cell Proliferation and Metastasis by Inhibiting YWHAZ-Mediated Epithelial-Mesenchymal Transition

Background

Colorectal cancer (CRC) is regarded as one of the most common malignancies in the world. MiR-1-3p was reported to be a tumor suppressor in CRC. However, the mechanisms have not been fully elucidated.

Methods

To identify CRC-associated miRNA, microarray data set GSE30454 was downloaded from the Gene Expression Omnibus database (GEO), and miR-1-3p was screened out as a candidate. The expression of miR-1-3p was detected using quantitative real-time polymerase chain reaction (qRT-PCR) in CRC cell lines and tissues. CCK-8 assay and transwell invasion assay were performed to determine CRC cell line proliferation and invasion, respectively. The levels of YWHAZ and EMT-associated proteins were detected using western blotting.

Results

Bioinformatic analysis showed that miR-1-3p was downregulated in CRC tissues, which is verified by our experimental validation. The overexpression of miR-1-3p significantly suppressed CRC cell proliferation and invasion. Further studies showed that YWHAZ was a direct target of miR-1-3p and mediated epithelial-mesenchymal transition (EMT) modulated by miR-1-3p.

Conclusion

Our results demonstrated that miR-1-3p suppresses colorectal cancer cell proliferation and metastasis through regulating YWHAZ-mediated EMT, which may support a novel therapeutic strategy for CRC patients.

Exosomes: The protagonists in the tale of colorectal cancer?

Exosomes, which facilitate intercellular communication, antigen presentation and shuttling of biological agents, were initially thought as the cell's garbage cargo but today, after about 40 years of their discovery, we are now beginning to understand their potential role in diagnosis and therapy of several diseases including cancers. Various studies over the decades have signified the role of exosomes in different stages of cancer. Exosomes play a key role in colorectal cancer initiation (CRC), promotion of anti- apoptotic signaling pathways, regulating tumor microenvironment, enhancing tumorigenicity, promotion of angiogenesis, stem cell proliferation and endothelial cell migration, establishment of immune suppressive environment, formation of pre- metastatic niche and metastasis. Exosomes also elicits drug resistance. Since, they have the ability to cross the biological barrier, exosomes are now being explored as an efficient target specific drug delivery system that facilitates the shipping of different biomolecules and therapeutic drugs. However, cautious and strong investigative approaches are required before approving exosomes as therapeutics or drug delivery systems. In this review, we summarize the role of exosomes in different stages of CRC and also elaborate on the applications of exosomes in diagnosis and therapy with respect to CRC.

Proteomic Approach for Searching for Universal, Tissue-Specific, and Line-Specific Markers of Extracellular Vesicles in Lung and Colorectal Adenocarcinoma Cell Lines

Tumor-derived extracellular vesicles (EVs), including exosomes, contain proteins that mirror the molecular landscape of producer cells. Being potentially detectible in biological fluids, EVs are of great interest for the screening of cancer biomarkers. To reveal universal, tissue-specific, and line-specific markers, we performed label-free mass spectrometric profiling of EVs originating from the human colon cancer cell lines Caco-2, HT29, and HCT-116, as well as from the lung cancer cell lines NCI-H23 and A549. A total of 651 proteins was identified in the EV samples using at least two peptides. These proteins were highly enriched in exosome markers. We found 11 universal, eight tissue-specific, and 29 line-specific markers, the levels of which were increased in EVs compared to the whole lysates. The EV proteins were involved in the EGFR, Rap1, integrin, and microRNA signaling associated with metastasis and cancer progression. An EV protein-based assay could be developed as a liquid biopsy tool.

Exosomal Non Coding RNA in LIQUID Biopsies as a Promising Biomarker for Colorectal Cancer

Colorectal cancer (CRC) is one of the most common cancers worldwide, with a high mortality rate, especially in those that are diagnosed in late stages of the disease. The current screening blood-based markers, such as carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9), have low sensitivity and specificity. Meanwhile, other modalities are either expensive or invasive. Therefore, recent research has shifted towards a minimally invasive test, namely, liquid biopsy. Exosomes are favorable molecules sought in blood samples, since they are abundant, stable in circulation, and harbor genetic information and other biomolecules that could serve as biomarkers or even therapeutic targets. Furthermore, exosomal noncoding RNAs, such as miRNAs, lncRNAs, and circRNAs, have demonstrated the diagnostic potential to detect CRC at an early stage with a higher sensitivity and specificity than CEA and CA19-9 alone. Moreover, they have prognostic potential that is TNM stage specific and could serve as predictive biomarkers for the most common chemotherapeutic drug and combination regimen in CRC, which are 5-FU and FOLFOX, respectively. Therefore, in this review, we focus on the role of these exosomal noncoding RNAs as diagnostic, prognostic, and predictive biomarkers. In addition, we discuss the advantages and challenges of exosomes as a liquid biopsy target.

The role of YWHAZ in cancer: A maze of opportunities and challenges

YWHAZ (also named 14-3-3ζ) is a central hub protein for many signal transduction pathways and plays a significant role in tumor progression. Accumulating evidences have demonstrated that YWHAZ is frequently up-regulated in multiple types of cancers and acts as an oncogene in a wide range of cell activities including cell growth, cell cycle, apoptosis, migration, and invasion. Moreover, YWHAZ was reported to be regulated by microRNAs (miRNAs) or long non-coding RNAs and exerted its malignant functions by targeting downstream molecules like protein kinase, apoptosis proteins, and metastasis-related molecules. Additionally, YWHAZ may be a potential biomarker of diagnosis, prognosis and chemoresistance in several cancers. Targeting YWHAZ by siRNA, shRNA or miRNA was reported to have great help in suppressing malignant properties of cancer cells. In this review, we perform literature and bioinformatics analysis to reveal the oncogenic role and molecular mechanism of YWHAZ in cancer, and discuss the potential clinical applications of YWHAZ concerning diagnosis, prognosis, and therapy in malignant tumors.

Stem cell derived exosomes: microRNA therapy for age-related musculoskeletal disorders

Age-associated musculoskeletal disorders (MSDs) have been historically overlooked by mainstream biopharmaceutical researchers. However, it has now been recognized that stem and progenitor cells confer innate healing capacity for the musculoskeletal system. Current evidence indicates that exosomes are particularly important in this process as they can mediate sequential and reciprocal interactions between cells to initiate and enhance healing. The present review focuses on stem cells (SCs) derived exosomes as a regenerative therapy for treatment of musculoskeletal disorders. We discuss mechanisms involving exosome-mediated transfer of RNAs and how these have been demonstrated in vitro and in vivo to affect signal transduction pathways in target cells. We envision that standardized protocols for stem cell culture as well as for the isolation and characterization of exosomes enable GMP-compliant large-scale production of SCs-derived exosomes. Hence, potential new treatment for age-related degenerative diseases can be seen in the horizon.

Stem cells and extracellular vesicles: biological regulators of physiology and disease

Many different subpopulations of subcellular extracellular vesicles (EVs) have been described. EVs are released from all cell types and have been shown to regulate normal physiological homeostasis, as well as pathological states by influencing cell proliferation, differentiation, organ homing, injury and recovery, as well as disease progression. In this review, we focus on the bidirectional actions of vesicles from normal and diseased cells on normal or leukemic target cells; and on the leukemic microenvironment as a whole. EVs from human bone marrow mesenchymal stem cells (MSC) can have a healing effect, reversing the malignant phenotype in prostate and colorectal cancer, as well as mitigating radiation damage to marrow. The role of EVs in leukemia and their bimodal cross talk with the encompassing microenvironment remains to be fully characterized. This may provide insight for clinical advances via the application of EVs as potential therapy and the employment of statistical and machine learning models to capture the pleiotropic effects EVs endow to a dynamic microenvironment, possibly allowing for precise therapeutic intervention.

Colorectal cancer cell-derived exosomes promote proliferation and decrease apoptosis by activating the ERK pathway

Exosomes are small microvesicles released by various cells that play important roles in cell-cell communication. Numerous studies show that colorectal cancer (CRC) cell-derived exosomes are involved in the progression of CRC. However, the specific ways and mechanisms of action have not yet been fully clarified. In the present study, we found that, compared to normal colon epithelial cell (NCM460) derived exosomes, CRC cell-Lovo derived exosomes (Lovo-exo) could be more easily taken up by Lovo cells, most likely because of their cell tropism. In addition, Lovo-exo promoted Lovo cell proliferation and inhibited apoptosis, which is associated with an increased activation of the extracellular signal-regulated protein kinase (ERK). Lovo-exo also dramatically increased Lovo tumor cell growth in vivo. Moreover, the intratumoral injection of GW4869 (an exosomes inhibitor) suppressed tumor growth. These results indicate that CRC cell Lovo-derived exosomes may be a messenger for the proliferation requirements of the originating cancer cells, and targeting tumor-derived exosomes may be very promising for tumor treatment.

TNF-α Modulates P-Glycoprotein Expression and Contributes to Cellular Proliferation via Extracellular Vesicles

P-glycoprotein (Pgp/ABCB1) overexpression is associated with multidrug resistance (MDR) phenotype and, consequently, failure in cancer chemotherapy. However, molecules involved in cell death deregulation may also support MDR. Tumor necrosis factor-alpha (TNF-α) is an important cytokine that may trigger either death or tumor growth. Here, we examined the role of cancer cells in self-maintenance and promotion of cellular malignancy through the transport of Pgp and TNF-α molecules by extracellular vesicles (membrane microparticles (MP)). By using a classical MDR model in vitro, we identified a positive correlation between endogenous TNF-α and Pgp, which possibly favored a non-cytotoxic effect of recombinant TNF-α (rTNF-α). We also found a positive feedback involving rTNF-α incubation and TNF-α regulation. On the other hand, rTNF-α induced a reduction in Pgp expression levels and contributed to a reduced Pgp efflux function. Our results also showed that parental and MDR cells spontaneously released MP containing endogenous TNF-α and Pgp. However, these MP were unable to transfer their content to non-cancer recipient cells. Nevertheless, MP released from parental and MDR cells elevated the proliferation index of non-tumor cells. Collectively, our results suggest that Pgp and endogenous TNF-α positively regulate cancer cell malignancy and contribute to changes in normal cell behavior through MP.

Mass spectrometry-based proteome profiling of extracellular vesicles and their roles in cancer biology

Over the past three decades, extracellular vesicles (EVs) have arisen as important mediators of intercellular communication that are involved in the transmission of biological signals between cells to regulate various biological processes. EVs are largely responsible for intercellular communication through the delivery of bioactive molecules, such as proteins, messenger RNAs (mRNAs), microRNAs (miRNAs), DNAs, lipids, and metabolites. EVs released from cancer cells play a significant role in signal transduction between cancer cells and the surrounding cells, which contributes to the formation of tumors and metastasis in the tumor microenvironment. In addition, EVs released from cancer cells migrate to blood vessels and flow into various biological fluids, including blood and urine. EVs and EV-loaded functional cargoes, including proteins and miRNAs, found in these biological fluids are important biomarkers for cancer diagnosis. Therefore, EV proteomics greatly contributes to the understanding of carcinogenesis and tumor progression and is critical for the development of biomarkers for the early diagnosis of cancer. To explore the potential use of EVs as a gateway to understanding cancer biology and to develop cancer biomarkers, we discuss the mass spectrometric identification and characterization of EV proteins from different cancers. Information provided in this review may help in understanding recent progress regarding EV biology and the potential roles of EVs as new noninvasive biomarkers and therapeutic targets.

Tumor cells release tiny membrane-encapsulated packages known as extracellular vesicles containing proteins which could serve as prognostic disease biomarkers or therapeutic targets. Kwang Pyo Kim and colleagues from Kyung Hee University in Yongin, South Korea, review the use of mass spectrometry to profile the diversity of proteins found in these tumor-derived packages. The proteins found in these vesicles help mediate communication between cancer cells and their surrounding tissues. Different tumor types share many of these proteins in common, but there are differences in the protein profile related to cancer-associated biological processes such as metastasis and cell proliferation. Tests based on the proteins contained in these vesicles could help clinicians better identify, diagnose and treat specific cancers, although large, multicenter studies are needed to validate such strategies.

A New Stem Cell Biology: Transplantation and Baseline, Cell Cycle and Exosomes

Hematopoietic stem cell biology has focused on stem cell purification and the definition of the regulation of purified stem cells in a hierarchical system. Work on the whole unpurified murine marrow cell population has indicated that a significant number of hematopoietic stem cells, rather than being dormant, are actively cycling, always changing phenotype and therefore resistant to purification efforts by current approaches. The bulk of cycling marrow stem cells are discarded with the standard lineage negative, stem cell marker positive separations. Therefore, the purified stem cells do not appear to be representative of the total hematopoietic stem cell population. In addition, baseline hematopoiesis does not appear to be determined by the transplantable stem cells but rather by many short-lived clones of varying differentiation potential. These systems appear to be impacted by tissue derived extracellular vesicles and a number of other variables. Thus hematopoietic stem cell biology is now at a fascinating new beginning with great promise.

14-3-3zeta is involved in the anticancer effect of metformin in colorectal carcinoma

Metformin is a promising drug for cancer prevention and treatment, especially in the diabetic population. We aimed to test whether 14-3-3zeta affects the anticancer effect of metformin on colorectal carcinoma (CRC). In this study, we confirmed that higher 14-3-3zeta expression was found in CRC tissues than in pericarcinoma tissues, and in CRC tissue of patients with diabetes than in those without diabetes. A knockdown of 14-3-3zeta inhibited CRC proliferation and promoted apoptosis in vitro and in vivo. Then, we created stable cell lines with under-expressed 14-3-3zeta from SW480 and HCT15 cells after infection by a lentiviral vector carrying short hairpin RNA targeting 14-3-3zeta (named LV-sh14-3-3zeta). Of note, metformin induced apoptosis and retarded tumor growth in the CRCs with overexpressed 14-3-3zeta, whereas this action was attenuated when 14-3-3zeta was knocked down. Moreover, either metformin or downregulation of 14-3-3zeta noticeably activated AMP-dependent protein kinase (AMPK) signaling, whereas the effect of metformin was attenuated when the 14-3-3zeta expression was decreased. Taken together, our results suggest that 14-3-3zeta may be associated with carcinogenesis and poor prognosis of CRCs associated with diabetes, and metformin may reverse the AMPK inhibition caused by 14-3-3zeta in CRCs in the background of diabetes. Our study should lead to a better understanding of the anticancer activity of metformin and points to possible application of metformin to the treatment of cancers overexpressing 14-3-3zeta.

The role of exosomes on colorectal cancer: A review

Exosomes are extracellular microvesicles released from cells, which are involved in many biological and pathological processes, mainly because of their role in intercellular communication. Exosomes derived from colorectal cancer (CRC) cells are related to oncogenesis, tumor cell survival, chemo-resistance, and metastasis. The role of the exosomes in these processes involves the transfer of proteins, RNAs, or mutant versions of proto-oncogenes to the target cells. In recent years, great efforts have been made to identify useful biomarkers in CRC exosomes for diagnosis, prediction of prognosis, and treatment response. This review focuses on recent studies on CRC exosomes, considering isolation, cargo, biomarkers, and the effects of exosomes on the development and progression of CRC, including resistance to antitumor therapy.

Monitoring the response of urothelial precancerous lesions to Bacillus Calmette-Guerin at the proteome level in an in vivo rat model

Intravesical Bacillus Calmette-Guerin (BCG) is the best treatment modality for progression of non-muscle invasive bladder cancer. We aimed to monitor changes at the proteome level to identify putative protein biomarkers associated with the response of urothelial precancerous lesions to intravesical BCG treatment. The rats were divided into three groups (n = 10/group): control, non-treated, and BCG-treated groups. The non-treated and BCG-treated groups received N-methyl-N-nitrosourea intravesically. BCG Tice-strain was instilled into bladder in BCG-treated group. At the endpoint of experiment, all surviving rat bladders were collected and equally divided into two portions vertically from dome to neck. Half of each bladder was assessed immunohistopathologically and the other half was used for 2D-based comparative proteomic analysis. Differentially expressed proteins were validated by Western blot analysis. Precancerous lesions of bladder cancer were more common in non-treated group (77.8%) than in BCG-treated group (50%) and the control group (0%). Greater than twofold changes occurred in the expression of a number of proteins. Among them, Rab-GDIβ, aldehyde dehydrogenase 2 (ALDH2) and 14-3-3 zeta/delta were important since they were previously reported to be associated with cancer and their expression levels were found to be lower in BCG-treated group in comparison to the non-treated group. ALDH2 and 14-3-3 zeta/delta were also found to be highly expressed in the non-treated group compared to the control group. The down-regulation of these proteins and Rab-GDIβ was achieved with BCG; this result indicates that they may be used as putative biomarkers for monitoring changes in bladder carcinogenesis in response to BCG immunotherapy.

Downregulation of 14-3-3β inhibits proliferation and migration in osteosarcoma cells

The 14-3-3 protein isoform β (14‑3‑3β), which is an intracellular adaptor protein that exists in all eukaryotic organisms, is highly expressed in many cancer tissues, including glioma, lung carcinoma and breast cancer. However, 14‑3‑3β expression and function in osteosarcoma progression remain unknown. In the present study, the endogenous expression of 14‑3‑3β was assessed in osteosarcoma samples and the effect of 14‑3‑3β knockdown was examined in human osteosarcoma MG63 cells using small interfering RNA (siRNA). mRNA and protein expression levels for 14‑3‑3β were detected by reverse transcription‑quantitative polymerase reaction and western blotting, respectively. The results demonstrated that endogenous 14‑3‑3β mRNA and protein were highly expressed in human osteosarcoma tissues and osteosarcoma cell lines (U2OS, MG63 and SaOs‑2), but not in normal bone tissues or normal osteoblast hFOB1.19 cells. These data suggested that increased expression of 14‑3‑3β may be significantly associated with the development and progression of osteosarcoma. Therefore, the effect of 14‑3‑3β knockdown in MG63 cells was further examined in vitro. Knockdown of 14‑3‑3β by siRNA significantly decreased cell viability, and inhibited cell proliferation and invasion. In addition, 14‑3‑3β knockdown significantly decreased the protein expression levels of β‑catenin, cyclin D1, v‑myc avian myelocytomatosis viral oncogene homolog and matrix metallopeptidase 9 in osteosarcoma MG63 cells. These results suggested that the anticancer effects of 14‑3‑3β knockdown in MG63 cells might be mediated by the inhibition of the Wnt/β‑catenin signaling pathway. In summary, 14‑3‑3β knockdown decreased proliferation and invasion in MG63 cells, which suggests a potential therapeutic application for 14‑3‑3β as a novel target for the treatment of osteosarcoma patients.

Identification and characteristics of extracellular vesicles from bovine blastocysts produced in vitro

Extracellular vesicles (EVs) have been identified within different body fluids and cell culture media. However, there is very little information on the secretion of these vesicles during early embryonic development. The aims of this work were first to demonstrate the secretion of extracellular vesicles by pre-implantation bovine embryos and second to identify and characterize the population of EVs secreted by bovine blastocysts during the period from day seven to nine of embryo culture and its correlation with further embryo development up to day 11. Bovine embryos were produced by in vitro fertilization (IVF) or parthenogenetic activation (PA) and cultured until blastocyst stage. Blastocyst selection was performed at day 7 post IVF/PA considering two variables: stage of development and quality of embryos. Selected blastocysts were cultured in vitro for 48 hours in groups (exp. 1) or individually (exp. 2) in SOF media depleted of exosomes. At day 9 post IVF/PA the media was collected and EVs isolated by ultracentrifugation. Transmission electron microscopy revealed the presence of heterogeneous vesicles of different sizes and population: microvesicles (MVs) and exosomes (EXs) of rounded shape, enclosed by a lipid bi-layer and ranging from 30 to 385 nm of diameter. Flow cytometry analysis allowed identifying CD63 and CD9 proteins as exosome markers. Nanoparticle tracking analysis generated a large number of variables, which required the use of multivariate statistics. The results indicated that the concentration of vesicles is higher in those blastocysts with arrested development from day 9 up to day 11 of in vitro development (6.7 x 10⁸ particles/ml) derived from IVF (p <0.05), compared to PA blastocysts (4.7 x 10⁸ particles/ml). Likewise, the profile (concentration and diameter) of particles secreted by embryos derived from IVF were different from those secreted by PA embryos. In conclusion, we demonstrated that bovine blastocysts secrete MVs/EXs to the culture media. Data suggest that characteristics of the population of EVs vary depending on embryo competence.