[Macrovipera lebetina obtusa Snake Venom as a Modulator of Antitumor Effect in S-180 Sarcoma Mouse Model].

Macrovipera lebetina obtusa (MLO) is a venomous snake endemic to Middle East. Here we describe the therapeutic potential of the MLO snake venom. In S-180 sarcoma-bearing mouse model, we showed that the MLO snake venom inhibits tumour growth by 50%. In human dermal microvascular endothelial cells (HMVEC-D), treatment with the MLO snake venom lead to an increase of expression levels of the vascular endothelial growth factor (VEGF), while the level of the expression of caspase 8 did not change. In HMVEC-D cells MLO snake venom induces necroptosis, rather than apoptosis. In the chick embryo chorioallantoic membrane (CAM) assay, exposure to MLO snake venom inhibited bFGF-induced angiogenesis by 22%. Taken together, these results indicate that the MLO snake venom has a potent cytotoxic activity. Regulated necroptic cell death pathway, which is engaged by MLO snake venom, may become a promising novel target for antitumor therapies.

Optimization of the use of a pharmaceutical grade xeno-free medium for in vitro expansion of human mesenchymal stem/stromal cells.

Human bone marrow-derived mesenchymal stem/stromal cells (hMSCs) are considered promising therapeutic agents in the field of cell therapy and regenerative medicine, mainly due to their relative facility to be isolated, multi-differentiation potential, and immunomodulatory role. However, their application in clinics requires a crucial step of in vitro expansion. Most of the protocols for hMSCs in vitro culture use foetal bovine serum as medium supplement that, being from animal origin, presents several safety concerns and may initiate xenogeneic immune responses after cells transplantation. This work reports the optimization of a pharmaceutical-grade xeno-free strategy for hMSCs in vitro expansion based on the supplementation of basal medium with a pharmaceutical-grade human plasma-derived supplement for cell culture (SCC) and 2 human growth factors (bFGF and TGFß1), plus a coating of human plasma fibronectin (Fn). After 4 weeks in culture, this strategy improves hMSCs expansion yield about 4.3-fold in comparison with foetal bovine serum supplementation and 4.5-fold compared with a commercially available xeno-free medium. hMSCs expanded in SCC-based formulation maintained their phenotype and differentiation capacity into osteogenic, adipogenic, and chondrogenic lineages, without alterations in cell karyotype. Overall, the SCC-based medium appears to be an excellent alternative for the xeno-free expansion of hMSCs as therapeutic agents for clinical applications.

Cdc42p controls yeast-cell shape and virulence of Paracoccidioides brasiliensis.

Paracoccidioides brasiliensis is characterized by a multiple budding phenotype and a polymorphic cell growth, leading to the formation of cells with extreme variations in shape and size. Since Cdc42 is a pivotal molecule in establishing and maintaining polarized growth for diverse cell types, as well as during pathogenesis of certain fungi, we evaluated its role during cell growth and virulence of the yeast-form of P. brasiliensis. We used antisense technology to knock-down PbCDC42's expression in P. brasiliensis yeast cells, promoting a decrease in cell size and more homogenous cell growth, altering the typical polymorphism of wild-type cells. Reduced expression levels also lead to increased phagocytosis and decreased virulence in a mouse model of infection. We provide genetic evidences underlying Pbcdc42p as an important protein during host-pathogen interaction and the relevance of the polymorphic nature and cell size in the pathogenesis of P. brasiliensis.