No abstract

Extracellular vesicles (EVs), including exosomes, have a key role in the paracrine communication between organs and compartments. EVs shuttle virtually all types of biomolecules such as proteins, lipids, nucleic acids, metabolites and even pharmacological compounds. Their ability to transfer their biomolecular cargo into target cells enables EVs to play a key role in intercellular communication that can regulate cellular functions such as proliferation, apoptosis and migration. This has led to the emergence of EVs as a key player in tumor growth and metastasis through the formation of "tumor niches" in target organs. Recent data have also been shown that EVs may transform the microenvironment of primary tumors thus favoring the selection of cancer cells with a metastatic behavior. The release of EVs from resident non-malignant cells may contribute to the metastatic processes as well. However, cancer EVs may induce malignant transformation in resident mesenchymal stem cells, suggesting that the metastatic process is not exclusively due to circulating tumor cells. In this review, we outline and discuss evidence-based roles of EVs in actively regulating multiple steps of the metastatic process and how we can leverage EVs to impair metastasis.

Exosomes are extracellular nanovesicles primarily involved in the pathogenesis of many diseases including cancer. This study was set out from recent evidence that extracellular acidity may increase the exosome release by cancer cells. However, this preliminary evidence did not provide solid information on whether the pH-dependent exosome over-release represents a common feature of all cancers. To the purpose of demonstrating that cancer acidity is a major determinant in inducing an increased exosome release by human cancer cells, we evaluated human tumor cell lines deriving from either colon, breast, prostate cancers, melanoma, or osteosarcoma. All cell lines were cultured in either the current 7.4 pH or the typical pH of cancer that is 6.5. The levels of released extracellular vesicles were measured by protein counts, nanoparticle tracking analysis (NTA), and nanoscale flow cytometry. The results showed that pH 6.5 induced a remarkable increase in exosome release, and buffering the medium significantly reduced the exosome release in all cancers. With these results, we provide, for the first time, evidence that tumor acidity and exosome levels represent common cancer phenotypes.

No abstract

Prostate Specific Antigen (PSA) fails to discriminate between benign prostatic hyperplasia (BPH) and Prostate Cancer (PCa), resulting in large numbers of unnecessary biopsies and missed cancer diagnoses. Nanovesicles called exosomes are directly detectable in patient plasma and here we explore the potential use of plasmatic exosomes expressing PSA (Exo-PSA) in distinguishing healthy individuals, BPH, and PCa. Exosomes were obtained from plasma samples of 80 PCa, 80 BPH, and 80 healthy donors (CTR). Nanoparticle Tracking Analysis (NTA), immunocapture-based ELISA (IC-ELISA), and nanoscale flow-cytometry (NSFC), were exploited to detect and characterize plasmatic exosomes. Statistical analysis showed that plasmatic exosomes expressing both CD81 and PSA were significantly higher in PCa as compared to both BPH and CTR, reaching 100% specificity and sensitivity in distinguishing PCa patients from healthy individuals. IC-ELISA, NSFC, and Exo-PSA consensus score (EXOMIX) showed 98% to 100% specificity and sensitivity for BPH-PCa discrimination. This study outperforms the conventional PSA test with a minimally invasive widely exploitable approach.