A significant proportion of extracellular nucleic acids in plasma circulate highly protected in tumor-specific exosomes, but it is unclear how the release of exosomes is modulated in carcinogenesis. We quantified by cytometry exosomes in plasma of 91 colorectal cancer patients to evaluate their potential as a tumor indicator and their repercussions on diagnosis and prognosis. We examined the involvement of TSAP6, a TP53-regulated gene involved in the regulation of vesicular secretion, in levels of circulating exosomes in plasma of colorectal patients and in HCT116 TP53-(wild-type and null) human colorectal cancer cell lines. The fraction of exosomes in cancer patients was statistically higher than in healthy controls (mean rank ¼ 53.93 vs. 24.35). High levels of exosomes in plasma of patients correlated with high levels of carcino-embryonic antigen (P ¼ 0.029) and with poorly differentiated tumors (P ¼ 0.039) and tended to have shorter overall survival than patients with low levels (P ¼ 0.056). Release of exosomes did not correlate with TSAP6 expression; and regulation of TSAP6 by TP53 was not shown either in tumor samples or in HCT116 cell lines. Although it was not suggested that the TP53/TSAP6 pathway regulates the release of exosomes into the plasma of colorectal cancer patients, the level of circulating exosomes may be used as a tumor indicator, because it correlates with poor prognosis parameters and shorter survival.

BackgroundCirculating cell-free miRNAs have emerged as promising minimally-invasive biomarkers for early detection, prognosis and monitoring of cancer. They can exist in the bloodstream incorporated into extracellular vesicles (EVs) and ribonucleoprotein complexes. However, it is still debated if EVs contain biologically meaningful amounts of miRNAs and may provide a better source of miRNA biomarkers than whole plasma. The aim of this study was to systematically compare the diagnostic potential of prostate cancer-associated miRNAs in whole plasma and in plasma EVs.MethodsRNA was isolated from whole plasma and plasma EV samples from a well characterised cohort of 50 patient with prostate cancer (PC) and 22 patients with benign prostatic hyperplasia (BPH). Nine miRNAs known to have a diagnostic potential for PC in cell-free blood were quantified by RT-qPCR and the relative quantities were compared between patients with PC and BPH and between PC patients with Gleason score ≥ 8 and ≤6.ResultsOnly a small fraction of the total cell-free miRNA was recovered from the plasma EVs, however the EV-incorporated and whole plasma cell-free miRNA profiles were clearly different. Four of the miRNAs analysed showed a diagnostic potential in our patient cohort. MiR-375 could differentiate between PC and BPH patients when analysed in the whole plasma, while miR-200c-3p and miR-21-5p performed better when analysed in plasma EVs. EV-incorporated but not whole plasma Let-7a-5p level could distinguish PC patients with Gleason score ≥ 8 vs ≤6.ConclusionsThis study demonstrates that for some miRNA biomarkers EVs provide a more consistent source of RNA than whole plasma, while other miRNAs show better diagnostic performance when tested in the whole plasma.

The aim of this study was to identify microRNAs in urinary exosomes that are differently expressed in prostate cancer patients and healthy donors. For this purpose, RNA was extracted from urinary exosomes from 20 prostate cancer patients and 9 healthy males and the microRNAs were analyzed by next generation sequencing. Interestingly, 5 microRNAs – miR-196a-5p, miR-34a-5p, miR-143-3p, miR-501-3p and miR-92a-1-5p – were significantly downregulated in exosomes from prostate cancer patients. Furthermore, RT-qPCR analysis of an independent cohort of 28 prostate cancer patients and 19 healthy males confirmed that miR-196a-5p and miR-501-3p were downregulated in prostate cancer samples. These results suggest that specific microRNAs in urinary exosomes might serve as non-invasive biomarkers for prostate cancer. In particular, miR-196a-5p and miR-501-3p are promising biomarkers that need to be further studied in large patient cohorts.Electronic supplementary materialThe online version of this article (10.1186/s12943-017-0726-4) contains supplementary material, which is available to authorized users.

Tumor-derived exosomes mediate tumorigenesis by facilitating tumor growth, metastasis, development of drug resistance, and immunosuppression. However, little is known about the exosomes isolated from bronchoalveolar lavage (BAL) in patients with lung neoplasm. Exosomes isolated in plasma and BAL from 30 and 75 patients with tumor and nontumor pathology were quantified by acetylcholinesterase activity and characterized by Western Blot, Electron Microscopy, and Nanoparticle Tracking Analysis. Differences in exosome cargo were analyzed by miRNA quantitative PCR in pooled samples and validated in a second series of patients. More exosomes were detected in plasma than in BAL in both groups (P < 0.001). The most miRNAs evaluated by PCR array were detected in tumor plasma, tumor BAL, and nontumor BAL pools, but only 56% were detected in the nontumor plasma pool. Comparing the top miRNAs with the highest levels detected in each pool, we found close homology only between the BAL samples of the two pathologies. In tumor plasma, we found a higher percentage of miRNAs with increased levels than in tumor BAL or in nontumor plasma. The data reveal differences between BAL and plasma exosome amount and miRNA content.

Tumor-derived exosomes are emerging as local and systemic cell-to-cell mediators of oncogenic information through the horizontal transfer of mRNAs, microRNAs and proteins during tumorigenesis. The exosomal content has been described as biologically active when taken up by the recipient cell. Identifying the specific molecular cargo of exosomes will help to determine their function in specific steps of the tumorigenic process. Here we evaluate whether ΔNp73 is selectively packaged in tumor-derived exosomes, its function in the acceptor cells in vitro and in vivo and its prognosis potential in cancer. ΔNp73 messenger is enriched in tumor-derived exosomes, suggesting its active sorting in these microvesicles. We observed the transmission of this exosome cargo to different cell types and how it confers proliferation potential and chemoresistance to the acceptor cells in vitro and in animal models. Finally, our data support the potential prognostic value of exosomal ΔNp73 in colon cancer patients.

Cancer cells efficiently transfer exosome contents (essentially mRNAs and microRNAs) to other cell types, modifying immune responses, cell growth, angiogenesis and metastasis. Here we analyzed the exosomes release by breast tumor cells with different capacities of stemness/metastasis based on CXCR4 expression, and evaluated their capacity to generate oncogenic features in recipient cells. Breast cancer cells overexpressing CXCR4 showed an increase in stemness-related markers, and in proliferation, migration and invasion capacities. Furthermore, recipient cells treated with exosomes from CXCR4-cells showed increased in the same abilities. Moreover, inoculation of CXCR4-cell-derived exosomes in immunocompromised mice stimulated primary tumor growth and metastatic potential. Comparison of nucleic acids contained into exosomes isolated from patients revealed a “stemness and metastatic” signature in exosomes of patients with worse prognosis. Finally, our data supported the view that cancer cells with stem-like properties show concomitant metastatic behavior, and their exosomes stimulate tumor progression and metastasis. Exosomes-derived nucleic acids from plasma of breast cancer patients are suitable markers in the prognosis of such patients.

Exosome production from cancer-associated fibroblasts seems to be an important driver of tumor progression. We report the first in-depth biotype characterization of ncRNAs, analyzed by Next Generation Sequencing and Bioinformatics, expressed in established primary human normal and cancer-associated fibroblasts (CAFs) from cancer and normal mucosa tissues from 9 colorectal cancer patients, and/or packaged in their derived exosomes. Differential representation and enrichment analyses based on these ncRNAs revealed a significant number of differences between the ncRNA content of exosomes and the expression patterns of the normal and cancer-associated fibroblast cells. ncRNA regulatory elements are specifically packaged in CAF-derived exosomes, supporting a specific cross-talk between CAFs and colon cancer cells and/or other stromal cells, mediated by exosomes. These sncRNAs are potential biomarkers present in cancer-associated fibroblast-derived exosomes, which should thereby contribute to developing new non-invasive diagnostic, prognostic and predictive methods for clinical applications in management of cancer patients.Electronic supplementary materialThe online version of this article (10.1186/s12943-018-0863-4) contains supplementary material, which is available to authorized users.

Purpose: Cumulative data support the role of DTAp73 variants in tumorigenic processes such as drug resistance. We evaluate the impact of TP73 isoforms and their putative target genes ABCB1, HMGB1, and CASP1 on the survival of colon cancer patients and the correlation between their expressions.Experimental Design: We determined in 77 colon cancer patients the expression of DEx2p73, DEx2/ 3p73, DNp73, TAp73, ABCB1, HMGB1, and CASP1 by quantitative real-time reverse transcriptase-PCR. Tumor characteristics, disease-free survival, and overall survival (OS) were examined in each patient. Functional experiments were carried out to check whether ectopic expression of DNp73 modifies the proliferation, drug resistance, migration, and invasion properties of colon tumor cells and the expression of ABCB1, HMGB1, and CASP1.Results: Positive correlations were observed between the expression levels of DTAp73 variants and HMGB1. Furthermore, a trend was observed for ABCB1. Overexpression of DEx2/3p73 and DNp73 isoforms was significantly associated with advanced stages (P ¼ 0.04 and P ¼ 0.03, respectively) and predicted shortened OS (P ¼ 0.04 and P ¼ 0.05, respectively). High levels of ABCB1 and HMGB1 were associated with shorter OS (P ¼ 0.04 and P ¼ 0.05, respectively). Multivariate analysis showed that, in addition to the tumor stage, ABCB1 and HMGB1 had independent relationships with OS (P ¼ 0.008). Ectopic expression of DNp73 was associated with an increase in proliferation and drug resistance.Conclusions: The positive correlation between DTAp73 variants and HMGB1 and ABCB1 expression supports them as TP73 targets. The fact that upregulation of DTAp73 isoforms was associated with shortened OS, increase in proliferation, and drug resistance confirms their oncogenic role and plausible value as prognostic markers. ABCB1 and HMGB1, putative DTAp73 target genes, strongly predict OS in an independent manner, making clear the importance of studying downstream TP73 targets that could predict the outcome of colon cancer patients better than DTAp73 variants themselves do.