Giant lysosomes as a chemotherapy resistance mechanism in hepatocellular carcinoma cells

Despite continuous improvements in therapeutic protocols, cancer-related mortality is still one of the main problems facing public health. The main cause of treatment failure is multi-drug resistance (MDR: simultaneous insensitivity to different anticancer agents), the underlying molecular and biological mechanisms of which include the activity of ATP binding cassette (ABC) proteins and drug compartmentalisation in cell organelles. We investigated the expression of the main ABC proteins and the role of cytoplasmic vacuoles in the MDR of six hepatocellular carcinoma (HCC) cell lines, and confirmed the accumulation of the yellow anticancer drug sunitinib in giant (four lines) and small cytoplasmic vacuoles of lysosomal origin (two lines). ABC expression analyses showed that the main ABC protein harboured by all of the cell lines was PGP, whose expression was not limited to the cell membrane but was also found on lysosomes. MTT assays showed that the cell lines with giant lysosomes were more resistant to sorafenib treatment than those with small lysosomes (p,0.01), and that verapamil incubation can revert this resistance, especially if it is administered after drug pre-incubation. The findings of this study demonstrate the involvement of PGP-positive lysosomes in drug sequestration and MDR in HCC cell lines. The possibility of modulating this mechanism using PGP inhibitors could lead to the development of new targeted strategies to enhance HCC treatment

Improvement of endurance of DMD animal model using natural polyphenols

Duchenne Muscular Dystrophy (DMD), the most common form of muscular dystrophy, is characterized by muscular wasting caused by dystrophin deficiency that ultimately ends in force reduction and premature death. In addition to primary genetic defect, several mechanisms contribute to DMD pathogenesis. Recently, antioxidant supplementation was shown to be effective in the treatment of multiple diseases including muscular dystrophy. Different mechanisms were hypothesized such as reduced hydroxyl radicals, nuclear factor-\u3baB deactivation and NO protection from inactivation. Following these promising evidences, we investigated the effect of the administration of a mix of dietary natural polyphenols (ProAbe) on dystrophic mdx mice in term of muscular architecture and functionality. We observed a reduction of muscle fibrosis deposition and myofiber necrosis together with an amelioration of vascolarization. More importantly, the recovery of the morphological features of dystrophic muscle leads to an improvement of the endurance of treated dystrophic mice. Our data confirmed that ProAbe-based diet may represent a strategy to co-adjuvate the treatment of DMD

Impaired Angiogenic Potential of Human Placental Mesenchymal Stromal Cells in Intrauterine Growth Restriction

Human placental mesenchymal stromal cells (pMSCs) have never been investigated in intrauterine growth restriction (IUGR). We characterized cells isolated from placental membranes and the basal disc of six IUGR and five physiological placentas. Cell viability and proliferation were assessed every 7 days during a 6-week culture. Expression of hematopoietic, stem, endothelial, and mesenchymal markers was evaluated by flow cytometry. We characterized the multipotency of pMSCs and the expression of genes involved in mitochondrial content and function. Cell viability was high in all samples, and proliferation rate was lower in IUGR compared with control cells. All samples presented a starting heterogeneous population, shifting during culture toward homogeneity for mesenchymal markers and occurring earlier in IUGR than in controls. In vitro multipotency of IUGR-derived pMSCs was restricted because their capacity for adipocyte differentiation was increased, whereas their ability to differentiate toward endothelial cell lineagewasdecreased. Mitochondrial content and function were higher in IUGR pMSCs than controls, possibly indicating a shift from anaerobic to aerobic metabolism, with the loss of the metabolic characteristics that are typical of undifferentiated multipotent cells

Cell Based Therapy for Duchenne Muscular Dystrophy

Mutations in the dystrophin gene cause an X-linked genetic disorder: Duchenne muscular dystrophy (DMD). Stem cell therapy is an attractive method to treat DMD because a small number of cells are required to obtain a therapeutic effect. Here, we discussed about multiple types of myogenic stem cells and their possible use to treat DMD. The identification of a stem cell population providing efficient muscle regeneration is critical for the progression of cell therapy for DMD. We speculated that the most promising possibility for the treatment of DMD is a combination of different approaches, such as gene and stem cell therapy

Cell Based Therapy for Duchenne Muscular Dystrophy

Mutations in the dystrophin gene cause an X-linked genetic disorder: Duchenne muscular dystrophy (DMD). Stem cell therapy is an attractive method to treat DMD because a small number of cells are required to obtain a therapeutic effect. Here, we discussed about multiple types of myogenic stem cells and their possible use to treat DMD. The identification of a stem cell population providing efficient muscle regeneration is critical for the progression of cell therapy for DMD. We speculated that the most promising possibility for the treatment of DMD is a combination of different approaches, such as gene and stem cell therapy

Mesenchymal and myogenic precursor cells : old partners for few interactions

In adult tissues, somatic stem cells represent a cell reservoir involved in physiological or pathological cell replacement. In several myopathies, chronic inflammation causes fibrotic infiltrations and adipose deposition within degenerating tissue. Starting from this evidence, we developed an experimental model for mimicking in vitro the effects of a damaged muscle on a specific stem cell population; the method is based on the simultaneous culture of stem cells and muscle tissue sections, in a microenvironment divided by a porous membrane, that guarantees soluble factors exchange but not cell migration. Human blood and adipose derived stem cells were grown in presence of normal (C57BL mouse) or dystrophic (mdx mouse model) muscle sections. Blood derived stem cells, co-cultured with muscle sections, showed an increase in cell proliferation and expression of mesenchymal markers, such as CD105, CD44, CD90, CD73 and CD29; moreover, they were able to express early myogenic differentiation markers, such as Myf5. Instead, human adipose derived stem cells showed an opposite behaviour; cells cultured in presence of both normal and dystrophic muscle tissue sections displayed an adipogenic differentiation. Moreover, the number of cells derived from the adipose mesenchymal stem cells and expressing Oil Red O lipid vacuole, Perilipin A and FABP4 was higher in the presence of dystrophic than normal muscle sections. These data suggest that the factors released by degenerating dystrophic muscle tissue may determine the commitment of mesenchymal stem cells into an adipogenic lineage underlying a new paradigm of the role of mesenchymal stem cells in the adipose formation of dystrophic muscle tissu