Extracellular Vesicles: New Players in Lymphomas

Lymphomas are heterogeneous diseases, and the term includes a number of histological subtypes that are characterized by different clinical behavior and molecular phenotypes. Valuable information on the presence of lymphoma cell-derived extracellular vesicles (LCEVs) in the bloodstream of patients suffering from this hematological cancer has recently been provided. In particular, it has been reported that the number and phenotype of LCEVs can both change as the disease progresses, as well as after treatment. Moreover, the role that LCEVs play in driving tumor immune escape has been reported. This makes LCEVs potential novel clinical tools for diagnosis, disease progression, and chemoresistance. LCEVs express surface markers and convey specific molecules in accordance with their cell of origin, which can be used as targets and thus lead to the development of specific therapeutics. This may be particularly relevant since circulating LCEVs are known to save lymphoma cells from anti-cluster of differentiation (CD)20-induced complement-dependent cytotoxicity. Therefore, effort should be directed toward investigating the feasibility of using LCEVs as predictive biomarkers of disease progression and/or response to treatment that can be translated to clinical use. The use of liquid biopsies in combination with serum EV quantification and cargo analysis have been also considered as potential approaches that can be pursued in the future. Upcoming research will also focus on the identification of specific molecular targets in order to generate vaccines and/or antibodies against LCEVs. Finally, the removal of circulating LCEVs has been proposed as a simple and non-invasive treatment approach. We herein provide an overview of the role of LCEVs in lymphoma diagnosis, immune tolerance, and drug resistance. In addition, alternative protocols that utilize LCEVs as therapeutic targets are discussed

State-of-the-Art and Future Directions in Organ Regeneration with Mesenchymal Stem Cells and Derived Products during Dynamic Liver Preservation

Transplantation is currently the treatment of choice for end-stage liver diseases but is burdened by the shortage of donor organs. Livers from so-called extended-criteria donors represent a valid option to overcome organ shortage, but they are at risk for severe post-operative complications, especially when preserved with conventional static cold storage. Machine perfusion technology reduces ischemia-reperfusion injury and allows viability assessment of these organs, limiting their discard rate and improving short- and long-term outcomes after transplantation. Moreover, by keeping the graft metabolically active, the normothermic preservation technique guarantees a unique platform to administer regenerative therapies ex vivo. With their anti-inflammatory and immunomodulatory properties, mesenchymal stem cells are among the most promising sources of therapies for acute and chronic liver failure, but their routine clinical application is limited by several biosafety concerns. It is emerging that dynamic preservation and stem cell therapy may supplement each other if combined, as machine perfusion can be used to deliver stem cells to highly injured grafts, avoiding potential systemic side effects. The aim of this narrative review is to provide a comprehensive overview on liver preservation techniques and mesenchymal stem cell-based therapies, focusing on their application in liver graft reconditioning

Effect of Esomeprazole Treatment on Extracellular Tumor pH in a Preclinical Model of Prostate Cancer by MRI-CEST Tumor pH Imaging

Novel anticancer treatments target the pH regulating system that plays a major role in tumor progression by creating an acidic microenvironment, although few studies have addressed their effect on tumor acidosis. In this study, we investigated in vivo several proton pump inhibitors (PPIs) targeting NHE-1 (Amiloride and Cariporide) and V-ATPase (Esomeprazole and Lansoprazole) proton transporters in the DU145 androgen-insensitive human prostate cancer model. In cellulo results showed that DU145 are sensitive, with decreasing efficacy, to Amiloride, Esomeprazole and Lansoprazole, with marked cell toxicity both in normoxia and in hypoxia, with almost any change in pH. In vivo studies were performed upon administration of Esomeprazole to assess both the acute and chronic effects, and Iopamidol-based tumor pH imaging was performed to evaluate tumor acidosis. Although statistically significant tumor pH changes were observed a few hours after Esomeprazole administration in both the acute study and up to one week of treatment in the chronic study, longer treatment resulted in a lack of changes in tumor acidosis, which was associated to similar tumor growth curves between treated and control groups in both the subcutaneous and orthotopic models. Overall, this study highlights MRI-CEST tumor pH imaging as a valid approach to monitoring treatment response to PPIs

Islet-Like Structures Generated In Vitro from Adult Human Liver Stem Cells Revert Hyperglycemia in Diabetic SCID Mice

A potential therapeutic strategy for diabetes is the transplantation of induced-insulin secreting cells. Based on the common embryonic origin of liver and pancreas, we studied the potential of adult human liver stem-like cells (HLSC) to generate in vitro insulin-producing 3D spheroid structures (HLSC-ILS). HLSC-ILS were generated by a one-step protocol based on charge dependent aggregation of HLSC induced by protamine. 3D aggregation promoted the spontaneous differentiation into cells expressing insulin and several key markers of pancreatic β cells. HLSC-ILS showed endocrine granules similar to those seen in human β cells. In static and dynamic in vitro conditions, such structures produced C-peptide after stimulation with high glucose. HLSC-ILS significantly reduced hyperglycemia and restored a normo-glycemic profile when implanted in streptozotocin-diabetic SCID mice. Diabetic mice expressed human C-peptide and very low or undetectable levels of murine C-peptide. Hyperglycemia and a diabetic profile were restored after HLSC-ISL explant. The gene expression profile of in vitro generated HLSC-ILS showed a differentiation from HLSC profile and an endocrine commitment with the enhanced expression of several markers of β cell differentiation. The comparative analysis of gene expression profiles after 2 and 4 weeks of in vivo implantation showed a further β-cell differentiation, with a genetic profile still immature but closer to that of human islets. In conclusion, protamine-induced spheroid aggregation of HLSC triggers a spontaneous differentiation to an endocrine phenotype. Although the in vitro differentiated HLSC-ILS were immature, they responded to high glucose with insulin secretion and in vivo reversed hyperglycemia in diabetic SCID mice

In Vivo MRI-CEST Tumor pH Imaging Detects Resistance to Proton Pump Inhibitors in Human Prostate Cancer Murine Models

The tumor microenvironment acidification confers treatment resistance; therefore, the interference with pH regulating systems is considered a new therapeutic strategy. In this study, two human prostate cancer cell lines, PC3 and LNCaP, have been treated in vitro with proton pump inhibitors (PPIs), namely Lansoprazole, Esomeprazole (V-ATPases-inhibitors), Cariporide, and Amiloride (NHE1-inhibitors). The cell viability and pH were assessed at several drug concentrations either at normoxic or hypoxic conditions. Since Esomeprazole showed the highest toxicity towards the PC3 cancer cells compared to LNCaP ones, athymic nude mice bearing subcutaneous or orthotopic PC3 tumors were treated with Esomeprazole (dose: 2.5 mg/kg body weight) for a period of three weeks—and tumor growth was monitored. MRI-CEST tumor pH imaging with Iopamidol was performed upon treatment at 3 h, 1 week (in combination with FDG-PET), and after 2 weeks for evaluating acute, early, and late responses. Although acute tumor pH changes were observed in vivo, long-term studies on both PC3 prostate cancer models did not provide any significant change in tumor acidosis or tumor growth. In conclusion, this work shows that MRI-CEST tumor pH imaging is a valuable tool for assessing the in vivo treatment response to PPIs