Smart nano-sized extracellular vesicles for cancer therapy: Potential theranostic applications in gastrointestinal tumors.

Extracellular vesicles (EVs) have gained tremendous interest in the search for next-generation therapeutics for the treatment of a range of pathologies, including cancer, especially due to their small size, biomolecular cargo, ability to mediate intercellular communication, high physicochemical stability, low immunogenicity and biocompatibility. The theranostic potential of EVs have been enhanced by adopting several strategies such as genetic or metabolic engineering, parental cell modification or direct functionalization to incorporate therapeutic compounds into these nanoplatforms. The smart nano-sized EVs indeed offer huge opportunities in the field of cancer, and current research is set at overcoming the existing pitfalls. Smart EVs are already being applied in the clinics despite the challenges faced. We provide, herein, an update on the technologies employed for EV functionalization in order to achieve optimal tumor cell targeting and EV tracking in vivo with bio-imaging modalities, as well as the preclinical and clinical studies making use of these modified EVs, in the context of gastrointestinal tumors.

Exploiting bioactive natural products of marine origin: Evaluation of the meroterpenoid metachromin V as a novel potential therapeutic drug for colorectal cancer.

Colorectal cancer (CRC) is the second most common cause of cancer death, leading to almost 1 million deaths per year. Despite constant progress in surgical and therapeutic protocols, the 5-year survival rate of advanced CRC patients remains extremely poor. Colorectal Cancer Stem Cells (CRC-CSCs) are endowed with unique stemness-related properties responsible for resistance, relapse and metastasis. The development of novel therapeutics able to tackle CSCs while avoiding undesired toxicity is a major need for cancer treatment. Natural products are a large reservoir of unexplored compounds with possible anticancer bioactivity, sustainability, and safety. The family of meroterpenoids derived from sponges share interesting bioactive properties. Bioassay-guided fractionation of a meroterpenoids extract led to the isolation of three compounds, all cytotoxic against several cancer cell lines: Metachromins U, V and W. In this study, we evaluated the anticancer potential of the most active one, Metachromins V (MV), on patient-derived CRC-CSCs. MV strongly impairs CSCs-viability regardless their mutational background and the cytotoxic effect is maintained on therapy-resistant metastatic CSCs. MV affects cell cycle progression, inducing a block in G2 phase in all the cell lines tested and more pronouncedly in CRC-CSCs. Moreover, MV triggers an important reorganization of the cytoskeleton and a strong reduction of Rho GTPases expression, impairing CRC-CSCs motility and invasion ability. By Proteomic analysis identified a potential molecular target of MV: CCAR1, that regulates apoptosis under chemotherapy treatments and affect ß-catenin pathway. Further studies will be needed to confirm and validate these data in in vivo experimental models.

Mutational status of plasma exosomal KRAS predicts outcome in patients with metastatic colorectal cancer.

Liquid biopsy has become a useful alternative in metastatic colorectal cancer (mCRC) patients when tissue biopsy of metastatic sites is not feasible. In this study we aimed to investigate the clinical utility of circulating exosomes DNA in the management of mCRC patients. Exosomes level and KRAS mutational status in exosomal DNA was assesed in 70 mCRC patients and 29 CRC primary tumor and were analysed at different disease steps evaluating serial blood samples (240 blood samples). There was a significant correlation between the extension of disease and exosomes level and the resection of primary localized tumor was correlated with a decrease of KRAS G12V/ D copies and fractional abundance in metastatic disease. CEA expression and liver metastasis correlated with a higher number of KRAS G12V/D copies/ml and a higher fractional abundance; in the subgroup of mCRC patients eligible for surgery, the size of tumor and the radiological response were related to exosomes level but only the size was related to the number of KRAS WT copies; both KRAS wild-type and mutated levels were identified as a prognostic factor related to OS. Finally, we found that 91% of mutated mCRC patients became wild type after the first line chemotherapy but this status reverted in mutated one at progression in 80% of cases. In a prospective cohort of mCRC patients, we show how longitudinal monitoring using exosome-based liquid biopsy provides clinical information relevant to therapeutic stratification.

Measuring Extracellular Vesicles by Conventional Flow Cytometry: Dream or Reality?

Intense research is being conducted using flow cytometers available in clinically oriented laboratories to assess extracellular vesicles (EVs) surface cargo in a variety of diseases. Using EVs of various sizes purified from the HT29 human colorectal adenocarcinoma cell line, we report on the difficulty to assess small and medium sized EVs by conventional flow cytometer that combines light side scatter off a 405 nm laser with the fluorescent signal from the EVs general labels Calcein-green and Calcein-violet, and surface markers. Small sized EVs (~70 nm) immunophenotyping failed, consistent with the scarcity of monoclonal antibody binding sites, and were therefore excluded from further investigation. Medium sized EVs (~250 nm) immunophenotyping was possible but their detection was plagued by an excess of coincident particles (swarm detection) and by a high abort rate; both factors affected the measured EVs concentration. By running samples containing equal amounts of Calcein-green and Calcein-violet stained medium sized EVs, we found that swarm detection produced false double positive events, a phenomenon that was significantly reduced, but not totally eliminated, by sample dilution. Moreover, running highly diluted samples required long periods of cytometer time. Present findings raise questions about the routine applicability of conventional flow cytometers for EV analysis.

Extracellular Vesicles and Cancer: A Focus on Metabolism, Cytokines, and Immunity.

A better understanding of the mechanisms of cell communication between cancer cells and the tumor microenvironment is crucial to develop personalized therapies. It has been known for a while that cancer cells are metabolically distinct from other non-transformed cells. This metabolic phenotype is not peculiar to cancer cells but reflects the characteristics of the tumor microenvironment. Recently, it has been shown that extracellular vesicles are involved in the metabolic switch occurring in cancer and tumor-stroma cells. Moreover, in an immune system, the metabolic programs of different cell subsets are distinctly associated with their immunological function, and extracellular vesicles could be a key factor in the shift of cell fate modulating cancer immunity. Indeed, during tumor progression, tumor-associated immune cells and fibroblasts acquire a tumor-supportive and anti-inflammatory phenotype due to their interaction with tumor cells and several findings suggest a role of extracellular vesicles in this phenomenon. This review aims to collect all the available evidence so far obtained on the role of extracellular vesicles in the modulation of cell metabolism and immunity. Moreover, we discuss the possibility for extracellular vesicles of being involved in drug resistance mechanisms, cancer progression and metastasis by inducing immune-metabolic effects on surrounding cells.

Low-intensity pulsed ultrasound affects growth, differentiation, migration, and epithelial-to-mesenchymal transition of colorectal cancer cells.

Ultrasound (US) offers potentially important opportunities from a therapeutic point of view. Thus, the study of the biological effects of US on cancer cells is important to understand the consequences of these changes on the malignant phenotype. This study aimed to investigate the effects of low-intensity ultrasound (LIPUS) on the phenotype of colorectal cancer cell lines. Cell proliferation was evaluated by viability test and by evaluation of pERK expression, while cell motility using the scratch test. Cell differentiation was evaluated assessing alkaline phosphatase activity. Epithelial mesenchymal transition was assessed by analyzing the expression of Vimentin and E-Cadherin. Release and uptake of extracellular vesicles (EVs) were evaluated by flow cytometry. LIPUS effects on the organization of cytoskeleton were analyzed by confocal microscopy and by evaluation of Rho GTPase expression. No alterations in vitality and clonogenicity were observed when the intermediate (0.4 MPa) and the lowest (0.035 MPa) acoustic intensities were administered while the treatment with high intensity (1 MPa) induced a reduction of both cell viability and clonogenicity in both cell lines in a frequency-dependent manner. LIPUS promoted the differentiation of colon cancer cells, affected epithelial-to-mesenchymal transition, promoted the closure of a wound as well as increased the release of EVs compared with untreated cells. LIPUS-induced increase in cell motility was likely due to a Rho GTPase-dependent mechanism. Overall, the results obtained warrant further studies on the potential combined effect of LIPUS with differentiating agents and on their potential use in a clinical setting.

CD147 Promotes Cell Small Extracellular Vesicles Release during Colon Cancer Stem Cells Differentiation and Triggers Cellular Changes in Recipient Cells.

Cancer cells secrete small extracellular vesicles (sEVs) that are involved in the remodeling of tumor microenvironment (TME) and can promote tumor progression. The role of sEVs and their molecular key players in colon cancer stem cells differentiation are poorly understood. This study aimed to analyze the role and content of sEVs released during the differentiation of colorectal cancer stem cells. Here we show that sEVs secretion during colon cancer stem cells differentiation is partially controlled by CD147, a well-known player involved in colon cancer tumorigenesis. CD147 + sEVs activate a signaling cascade in recipient cells inducing molecular invasive features in colon cancer cells. CD147 knockdown as well as anti-CD147 antibodies impaired sEVs release and downstream effects on recipient cells and blocking multivesicular body maturation prevented sEVs release during the differentiation. Our findings reveal a functional role of CD147 in promoting sEVs release during the differentiation of colon cancer stem cells and in triggering cellular changes in recipient cells.