Extract from Arrabidaea chica (Fridericia chica) leaves show preventive action for the mitigation of doxorubicin-induced cardiotoxicity / [Extrato das folhas de Arrabidaea chica (Fridericia chica) mostrou potencial ação no combate à cardiotoxicidade induzida pela doxorrubicina]

A doxorrubicina (dox) é um medicamento antineoplásico que induz cardiotoxicidade por estresse oxidativo. Os flavonoides são antioxidantes extraídos de plantas como Camellia sinensis e Arrabidaea chica (Fridericia chica). Esta pesquisa objetivou avaliar efeitos protetores do extrato de A. chica (AC), comparado ao de C. sinensis (CS), frente ao estresse oxidativo induzido pela dox, no coração. Cardiomiócitos e células neoplásicas MDA-MB 231 foram incubados com AC e CS. Depois, adicionou-se dox e avaliaram-se taxas de viabilidade e morte celular. A citometria de fluxo para o ensaio de iodeto de propídeo (IP) em cardiomiócitos mostrou as seguintes taxas de morte celular: controle 53%; dox 78% (maior que controle, P=0,015); AC_12,5µg/mL + dox 65% (menor que dox, P=0,031); AC_25µg/mL + dox 62% (menor que dox, P=0,028); AC_50µg/mL + dox 63% (menor que dox, P=0,030); CS_12,5µg/mL + dox 71% (menor que dox, P=0,040); CS_25µg/ml + dox 69% (menor que dox, P=0,037); CS_50µg/mL + dox 74% (menor que dox, P=0,044). Resultados das células MDA-MB 231 mostraram que nenhum extrato interferiu na atividade antitumoral da dox. Os dados de IP foram corroborados pelos de MTT. Este estudo reporta promissora utilização de A. chica na prevenção da cardiotoxicidade induzida pela dox.(AU)

CLA-supplemented diet accelerates experimental colorectal cancer by inducing TGF-ß-producing macrophages and T cells.

Conjugated linoleic acid (CLA) has been shown to activate the nuclear receptor PPAR-γ and modulate metabolic and immune functions. Despite the worldwide use of CLA dietary supplementation, strong scientific evidence for its proposed beneficial actions are missing. We found that CLA-supplemented diet reduced mucosal damage and inflammatory infiltrate in the dextran sodium sulfate (DSS)-induced colitis model. Conditional deletion of PPAR-γ in macrophages from mice supplemented with CLA diet resulted in loss of this protective effect of CLA, suggesting a PPAR-γ-dependent mechanism mediated by macrophages. However, CLA supplementation significantly worsened colorectal tumor formation induced by azoxymethane and DSS by inducing macrophage and T-cell-producing TGF-ß via PPAR-γ activation. Accordingly, either macrophage-specific deletion of PPAR-γ or in vivo neutralization of latency-associated peptide (LAP, a membrane-bound TGF-ß)-expressing cells abrogated the protumorigenic effect of CLA. Thus, the anti-inflammatory properties of CLA are associated with prevention of colitis but also with development of colorectal cancer.

BNNT/Fe3O4 System as an Efficient Tool for Magnetohyperthermia Therapy.

Nanostructured materials have been widely studied aiming to biomedical applications, primarily for the purpose of carrying drugs or molecules of interest in a selected tissue or organ. In this context, boron nitride nanotubes (BNNTs), when functionalized with specific moieties, could be useful as nanovectors for delivery of proteins, drugs, and also RNAi molecules, due to their capacity to be uptaked by cells. The introduction of magnetic nanoparticles allows the use of such system as a hyperthermia agent. Thus, once it has been targeted to tumor areas, it could kill cancer cells by magnetohyperthermia therapy. In order to study this effect, magnetite nanoparticles were incorporated into hydroxilated BNNT. The system was characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and vibrating sample magnetometry (VSM). The results obtained show that magnetite nanoparticles are linked to the nanotubes. Magnetic measurements show that coercivity and magnetization were not disturbed after incorporation to the BNNT. Based on this, a new methodology for in vitro magnetohyperthermia experiments was developed, aiming to treat each cell group individually preserving its sterility. The biological assays of the system demonstrate its good cell viability and the great potential of this nanomaterial as a magnetohyperthermia agent for cancer treatment.