Bothrops moojeni L-amino acid oxidase induces apoptosis and epigenetic modulation on Bcr-Abl+ cells

Resistance to apoptosis in chronic myeloid leukemia (CML) is associated with constitutive tyrosine kinase activity of the Bcr-Abl oncoprotein. The deregulated expression of apoptosis-related genes and alteration in epigenetic machinery may also contribute to apoptosis resistance in CML. Tyrosine kinase inhibitors target the Bcr-Abl oncoprotein and are used in CML treatment. The resistance of CML patients to tyrosine kinase inhibitors has guided the search for new compounds that may induce apoptosis in Bcr-Abl+ leukemic cells and improve the disease treatment. Methods: In the present study, we investigated whether the L-amino acid oxidase isolated from Bothrops moojeni snake venom (BmooLAAO-I) (i) was cytotoxic to Bcr-Abl+ cell lines (HL-60.Bcr-Abl, K562-S, and K562-R), HL-60 (acute promyelocytic leukemia) cells, the non-tumor cell line HEK-293, and peripheral blood mononuclear cells (PBMC); and (ii) affected epigenetic mechanisms, including DNA methylation and microRNAs expression in vitro. Results: BmooLAAO-I induced ROS production, apoptosis, and differential DNA methylation pattern of regulatory apoptosis genes. The toxin upregulated expression of the pro-apoptotic genes BID and FADD and downregulated DFFA expression in leukemic cell lines, as well as increased miR-16 expression - whose major predicted target is the anti-apoptotic gene BCL2 - in Bcr-Abl+ cells. Conclusion: BmooLAAO-I exerts selective antitumor action mediated by H2O2 release and induces apoptosis, and alterations in epigenetic mechanisms. These results support future investigations on the effect of BmooLAAO-I on in vivo models to determine its potential in CML therapy.(AU)

An alternative method to isolate protease and phospholipase A2 toxins from snake venoms based on partitioning of aqueous two-phase systems

Snake venoms are rich sources of active proteins that have been employed in the diagnosis and treatment of health disorders and antivenom therapy. Developing countries demand fast economical downstream processes for the purification of this biomolecule type without requiring sophisticated equipment. We developed an alternative, simple and easy to scale-up method, able to purify simultaneously protease and phospholipase A2 toxins from Bothrops alternatus venom. It comprises a multiple-step partition procedure with polyethylene-glycol/phosphate aqueous two-phase systems followed by a gel filtration chromatographic step. Two single bands in SDS-polyacrylamide gel electrophoresis and increased proteolytic and phospholipase A2 specific activities evidence the homogeneity of the isolated proteins.

Toxinas de serpientes con alto potencial terapéutico y su uso en la biomedicina / Animal toxins with high therapeutic potential and their use in biomedicine

Los venenos de animales son mezclas complejas de proteínas, péptidos, enzimas y trazas de elementosno proteicos tales como carbohidratos y sales, cuya finalidad es inmovilizar la presa ycomenzar a digerirla; algunos de estos compuestos han sido aislados y caracterizados o descritoscomo toxinas letales, o se les han atribuido acciones potentes sobre proteínas específicas como, porejemplo, las involucradas en la coagulación sanguínea. Debido al descubrimiento en 1971 del péptidoque dio origen al captopril y al entendimiento de los efectos potenciales de las toxinas, se empezó aconsiderar que los venenos de animales son fuentes ricas en compuestos bioactivos, que no soloproporcionan las herramientas necesarias para descifrar los detalles moleculares de diversos procesosfisiológicos, sino que también sirven como fuente de inspiración para diseñar y desarrollaragentes terapéuticos. Este artículo expone la aplicación de nuevas alternativas terapéuticas y demodelos para el diseño de las mismas basados en algunas moléculas aisladas de venenos de serpientescon alto potencial en campos como la biomedicina y la farmacia.

Animal venoms are complex mixtures of proteins, peptides, enzymes and trace elements such ascarbohydrates and salts, which serve to immobilize preys and to begin their digestion. Some ofthese compounds have been isolated and characterized, or described as lethal toxins, while othershave powerful actions on specific proteins, such as those involved in blood coagulation. Due to thediscovery in 1971 of the peptide that gave rise to captopril and to a better understanding of thepotential effects of toxins, animal venoms started to be considered as rich sources of bioactive compounds, which not only provide the necessary toolsto decipher molecular details of various physiologicalprocesses, but also are a source of inspiration to designand develop a range of new therapeutic agents. Thisreview presents the application of new therapeuticoptions or models to design them based on certainmolecules isolated from snake venoms, with highpotential in fields such as biomedicine and pharmacy.