Berberine associated photodynamic therapy promotes autophagy and apoptosis via ROS generation in renal carcinoma cells.

Renal cell carcinoma (RCC) consists of the most lethal common urological cancer and the clinical practice has shown that resistant RCC to commons therapies is extremely high. Berberine is an isoquinoline alkaloid, presents in different kinds of plants and it has long been used in Chinese medicine. It has several properties, such as antioxidant, anti-inflammatory, anti-diabetic, anti-microbial and anti-cancer. Moreover, berberine has photosensitive characteristics and its association with photodynamic therapy (PDT) is effective against tumor cells. This study aimed to evaluate the effects of berberine associated with PDT in renal carcinoma cell lines. The cellular viability assay showed increased cytotoxicity in concentration and time-dependent manner. Berberine presented efficient internalization in all cell lines analyzed. In addition, after treatment with berberine associated with PDT, it was observed a high phototoxicity effect with less than 20 % of viable cells. In this study we observed that the increase of reactive oxygen species (ROS) levels was accompanied by an increase of autophagy levels and apoptosis by caspase 3 activity, suggesting cell death by both mechanisms. Additionally, three target genes of anti-cancer drugs were differentially expressed in 786-O cells, being that Vascular Endothelial Growth Factor-D (FIGF) and Human Telomerase Reverse Transcriptase (TERT) gene presented low expression and Polo Like Kinase 3 (PLK3) presented overexpression after treatment with berberine associated with PDT. In this study, the proposed treatment triggered metabolites changes related to cell proliferation, tumorigenesis and angiogenesis. Thus, it was possible to suggest that berberine has promising potential as a photosensitizing agent in a photodynamic therapy, because it induced significant anticancer effects on renal carcinoma cells.

Thermodynamic analysis of interactions of the Hsp90 with adenosine nucleotides: A comparative perspective.

Hsp90s are key proteins in cellular homeostasis since they interact with many client proteins. Several studies indicated that Hsp90s are potential targets for treating diseases, such as cancer or malaria. It has been shown that Hsp90s from different organisms have peculiarities despite their high sequence identity. Therefore, a detailed comparative analysis of several Hsp90 proteins is relevant to the overall understanding of their activity. Accordingly, the goal of this work was to evaluate the interaction of either ADP or ATP with recombinant Hsp90s from different organisms (human α and ß isoforms, Plasmodium falciparum, Leishmania braziliensis, yeast and sugarcane) by isothermal titration calorimetry. The measured thermodynamic signatures of those interactions indicated that despite the high identity among all Hsp90s, they have specific thermodynamic characteristics. Specifically, the interactions with ADP are driven by enthalpy but are opposed by entropy, whereas the interaction with ATP is driven by both enthalpy and entropy. Complimentary structural and molecular dynamics studies suggested that specific interactions with ADP that differ from those with ATP may contribute to the observed enthalpies and entropies. Altogether, the data suggest that selective inhibition may be more easily achieved using analogues of the Hsp90-ADP bound state than those of Hsp90-ATP bound state.

Metabolic Effects of Cobalt Ferrite Nanoparticles on Cervical Carcinoma Cells and Nontumorigenic Keratinocytes.

The cytotoxic response, cellular uptake, and metabolomic profile of HeLa and HaCaT cell lines treated with cobalt ferrite nanoparticles (CoFe2O4 NPs) were investigated in this study. Cell viability assays showed low cytotoxicity caused by the uptake of the nanoparticles at 2 mg/mL. However, metabolomics revealed that these nanoparticles impacted cell metabolism even when tested at a concentration that presented low cytotoxicity according to the cell viability assay. The two cell lines shared stress-related metabolic changes such as increase in alanine and creatine levels. A reduced level of fumarate was also observed in HeLa cells after treatment with the nanoparticles, and this alteration can inhibit tumorigenesis. Fumarate is considered to be an oncometabolite that can inhibit prolyl hydroxylase, and this inhibition stabilizes HIF1α, one of the master regulators of tumorigenesis that promotes tumor growth and development. In summary, this study showed that nanoparticle-treated HeLa cells demonstrated decreased concentrations of metabolites associated with cell proliferation and tumor growth. The results clearly indicated that treatment with these nanoparticles might cause a perturbation in cellular metabolism.

Recent advances in the understanding of brown spider venoms: From the biology of spiders to the molecular mechanisms of toxins.

The Loxosceles genus spiders (the brown spiders) are encountered in all the continents, and the clinical manifestations following spider bites include skin necrosis with gravitational lesion spreading and occasional systemic manifestations, such as intravascular hemolysis, thrombocytopenia and acute renal failure. Brown spider venoms are complex mixtures of toxins especially enriched in three molecular families: the phospholipases D, astacin-like metalloproteases and Inhibitor Cystine Knot (ICK) peptides. Other toxins with low level of expression also present in the venom include the serine proteases, serine protease inhibitors, hyaluronidases, allergen factors and translationally controlled tumor protein (TCTP). The mechanisms by which the Loxosceles venoms act and exert their noxious effects are not fully understood. Except for the brown spider venom phospholipase D, which causes dermonecrosis, hemolysis, thrombocytopenia and renal failure, the pathological activities of the other venom toxins remain unclear. The objective of the present review is to provide insights into the brown spider venoms and loxoscelism based on recent results. These insights include the biology of brown spiders, the clinical features of loxoscelism and the diagnosis and therapy of brown spider bites. Regarding the brown spider venom, this review includes a description of the novel toxins revealed by molecular biology and proteomics techniques, the data regarding three-dimensional toxin structures, and the mechanism of action of these molecules. Finally, the biotechnological applications of the venom components, especially for those toxins reported as recombinant molecules, and the challenges for future study are discussed.