Exosome-mediated transfer of miR-222 is sufficient to increase tumor malignancy in melanoma

BACKGROUND: Growing evidence is showing that metastatic cell populations are able to transfer their characteristics to less malignant cells. Exosomes (EXOs) are membrane vesicles of endocytic origin able to convey their cargo of mRNAs, microRNAs (miRs), proteins and lipids from donors to proximal as well as distant acceptor cells. Our previous results indicated that miR-221&222 are key factors for melanoma development and dissemination. The aim of this study was to verify whether the tumorigenic properties associated with miR-222 overexpression can be also propagated by miR-222-containing EXOs. METHODS: EXOs were isolated by UltraCentrifugation or Exoquick-TC(®) methods. Preparations of melanoma-derived vesicles were characterized by using the Nanosight™ technology and the expression of exosome markers analyzed by western blot. The expression levels of endogenous and exosomal miRNAs were examined by real time PCR. Confocal microscopy was used to evaluate transfer and uptake of microvesicles from donor to recipient cells. The functional significance of exosomal miR-222 was estimated by analyzing the vessel-like process formation, as well as cell cycle rates, invasive and chemotactic capabilities. RESULTS: Besides microvesicle marker characterization, we evidenced that miR-222 exosomal expression mostly reflected its abundance in the cells of origin, correctly paralleled by repression of its target genes, such as p27Kip1, and induction of the PI3K/AKT pathway, thus confirming its functional implication in cancer. The possible differential significance of PI3K/AKT blockade was assessed by using the BKM120 inhibitor in miR-222-transduced cell lines. In addition, in vitro cultures showed that vesicles released by miR-222-overexpressing cells were able to transfer miR-222-dependent malignancy when taken-up by recipient primary melanomas. Results were confirmed by antagomiR-221&222 treatments and by functional observations after internalization of EXOs devoid of these miRs

Absence of Caspase 8 and High Expression of PED Protect Primitive Neural Cells from Cell Death

The mechanisms that control neural stem and progenitor cell survival are unknown. In several pathological conditions, death receptor (DR) ligands and inflammatory cytokines exert a deleterious effect on neurons, whereas primitive neural cells migrate and survive in the site of lesion. Here, we show that even in the presence of inflammatory cytokines, DRs are unable to generate death signals in primitive neural cells. Neural stem and progenitor cells did not express caspase 8, the presence of which is required for initiating the caspase cascade. However, exogenous or cytokine-mediated expression of caspase 8 was not sufficient to restore their DR sensitivity. Searching for molecules potentially able to block DR death-inducing signaling complex (DISC), we found that primitive neural cells expressed high levels of the death effector domain-containing protein PED (also known as PEA-15). PED localized in the DISC and prevented caspase 8 recruitment and activation. Moreover, lentiviral-mediated delivery of PED antisense DNA resulted in dramatic down-regulation of the endogenous gene expression and sensitization of primitive neural cells to apoptosis mediated by inflammatory cytokines and DRs. Thus, absence of caspase 8 and high expression of PED constitute two levels of protection from apoptosis induced by DRs and inflammatory cytokines in neural stem and progenitor cells

IL-4 Protects Tumor Cells from Anti-CD95 and Chemotherapeutic Agents via Up-Regulation of Antiapoptotic Proteins

We recently proposed that Th1 and Th2 cytokines exert opposite effects on the pathogenesis and clinical outcome of organ-specific autoimmunity by altering the expression of genes involved in target cell survival. Because a Th2 response against tumors is associated with poor prognosis, we investigated the ability of IL-4 to protect tumor cells from death receptor- and chemotherapy-induced apoptosis. We found that IL-4 treatment significantly reduced CD95 (Fas/APO-1)- and chemotherapeutic drug-induced apoptosis in prostate, breast, and bladder tumor cell lines. Analysis of antiapoptotic protein expression revealed that IL-4 stimulation resulted in up-regulation of cellular (c) FLIP/FLAME-1 and Bcl-xL. Exogenous expression of cFLIP/FLAME-1 inhibited apoptosis induced by CD95 and to a lesser extent by chemotherapy, while tumor cells transduced with Bcl-xLwere substantially protected both from CD95 and chemotherapeutic drug stimulation. Moreover, consistent IL-4 production and high expression of both cFLIP/FLAME-1 and Bcl-xLwere observed in primary prostate, breast, and bladder cancer in vivo. Finally, primary breast cancer cells acquired sensitivity to apoptosis in vitro only in the absence of IL-4. Thus, IL-4 protects tumor cells from CD95- and chemotherapy-induced apoptosis through the up-regulation of antiapoptotic proteins such as cFLIP/FLAME-1 and Bcl-xL. These findings may provide useful information for the development of therapeutic strategies aimed at restoring the functionality of apoptotic pathways in tumor cells

The botanical drug PBI-05204, a supercritical CO2 extract of Nerium oleander, sensitizes alveolar and embryonal rhabdomyosarcoma to radiotherapy in vitro and in vivo

: Treatment of rhabdomyosarcoma (RMS), the most common a soft tissue sarcoma in childhood, provides intensive multimodal therapy, with radiotherapy (RT) playing a critical role for local tumor control. However, since RMS efficiently activates mechanisms of resistance to therapies, despite improvements, the prognosis remains still largely unsatisfactory, mainly in RMS expressing chimeric oncoproteins PAX3/PAX7-FOXO1, and fusion-positive (FP)-RMS. Cardiac glycosides (CGs), plant-derived steroid-like compounds with a selective inhibitory activity of the Na+/K+-ATPase pump (NKA), have shown antitumor and radio-sensitizing properties. Herein, the therapeutic properties of PBI-05204, an extract from Nerium oleander containing the CG oleandrin already studied in phase I and II clinical trials for cancer patients, were investigated, in vitro and in vivo, against FN- and FP-RMS cancer models. PBI-05204 induced growth arrest in a concentration dependent manner, with FP-RMS being more sensitive than FN-RMS, by differently regulating cell cycle regulators and commonly upregulating cell cycle inhibitors p21Waf1/Cip1 and p27Cip1/Kip1. Furthermore, PBI-05204 concomitantly induced cell death on both RMS types and senescence in FN-RMS. Notably, PBI-05204 counteracted in vitro migration and invasion abilities and suppressed the formation of spheroids enriched in CD133+ cancer stem cells (CSCs). PBI-05204 sensitized both cell types to RT by improving the ability of RT to induce G2 growth arrest and counteracting the RT-induced activation of both Non-Homologous End-Joining and homologous recombination DSBs repair pathways. Finally, the antitumor and radio-sensitizing proprieties of PBI-05204 were confirmed in vivo. Notably, both in vitro and in vivo evidence confirmed the higher sensitivity to PBI-05204 of FP-RMS. Thus, PBI-05204 represents a valid radio-sensitizing agent for the treatment of RMS, including the intrinsically radio-resistant FP-RMS

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Stem cell factor protects erythroid precursor cells from chemotherapeutic agents via up-regulation of Bcl-2 family proteins

Suppression of red blood cell production is a common complication of chemotherapy, causing anemia in a significant number of cancer patients. We have evaluated the sensitivity of human hematopoietic progenitors and erythroid precursor cells to chemotherapeutic drugs and found that probasophilic erythroblasts represent the stage of erythroid differentiation more vulnerable to the cytotoxic effects of myelosuppressive agents. Stem cell factor (SCF) supports proliferation and survival of early hematopoietic cells by binding to the c-kit receptor. In unilineage erythropoietic culture of CD34+ progenitors, short-term pretreatment of immature erythroid precursors with SCF results in protection from apoptosis induced by chemotherapeutic agents and restores normal proliferation and differentiation after removal of the cytotoxic stimulus. The levels of drug-induced caspase processing are significantly reduced in erythroblasts treated with SCF, indicating that activation of the c-kit receptor generates antiapoptotic signals acting before amplification of the caspase cascade. Accordingly, we found that SCF up-regulates Bcl-2 and Bcl-XL in erythroid precursors and that exogenous expression of these proteins protects erythroblasts from caspase activation and death induced by chemotherapeutic agents. These results suggest a possible mechanism for SCF-mediated protection of erythroid precursor cells from apoptosis and may contribute to devise new strategies for prevention and treatment of chemotherapy-induced anemia. © 2003 by The American Society of Hematology

Ultrastructural morphology of equine adipose-derived mesenchymal stem cells

Mesenchymal stem cells are a virtually ubiquitous population of adult stem cells, able to differentiate into various tissue lineages. As they are multipotent and easy to grow in culture, they are at present considered very attractive candidates for tissue repair and gene therapy. With the exception of a few reports, mesenchymal stem cell morphology has been widely disregarded in the past years. In this paper we discuss the establishment of mesenchymal stem cell cultures from equine adipose tissue and describe their fine structure by transmission electron microscopy. The cultured cells revealed a fibroblastoid appearance and were characterized by an eccentric nucleus with multiple nucleoli, dense cytoplasm rich in ribosomes, a rough endoplasmic reticulum with dilated cisternae, elongated mitochondria and heterogeneous vacuolar inclusions. In addition, they were often interconnected by adhesion structures located on the cell body and on cytoplasmic processes contacting other cells. The features observed are evocative of an undifferentiated cellular phenotype and of an intense synthetic and metabolic activity