Tetanus toxin selectively impairs anti-tumoral but not anti-microbial macrophage-mediated effector functions

Abstract The present study was designed to establish the susceptibility of macrophage-mediated effector functions to tetanus toxin (TT). Using the murine macrophage cell line, GG2EE, generated in vitro by v- raf /v- myc oncogenes, we have previously provided evidence that TT selectively inhibits interferon gamma (IFN-γ), but not basal, lysozyme activity. Here we show that while neither phagocytic nor candidacidal activities are affected by TT treatment, antitumoral activity is significantly impaired after exposure to TT. This phenomenon, which is dose-dependent, is fully ascribed to the holotoxin, as heat inactivated TT, C or A-B fragments result ineffective. Furthermore, C but not A-B fragment competes with TT in abrogating its inhibitory effects. Overall, these data indicate that TT is not a broad-spectrum, down-regulating signal on macrophage-mediated functions, thus implying that its toxic action is exerted on specific molecular targets.     

Targeting TRAIL

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), also known as Apo2L, has been investigated in the past decade for its promising anticancer activity due to its ability to selectively induce apoptosis in tumoral cells by binding to TRAIL receptors (TRAIL-R). Macromolecules such as agonistic monoclonal antibodies and recombinant TRAIL have not proven efficacious in clinical studies, therefore several small molecules acting as TRAIL-R agonists are emerging in the scientific literature. In this work we focus on systemizing these drug molecules described in the past years, in order to better understand and predict the requirements for a novel anti-tumoral therapy based on the TRAIL-R-induced apoptotic mechanism.     

Macrovipecetin,a C-type lectin from Macrovipera lebetina venom,inhibits proliferation migration and invasion of SK-MEL-28 human melanoma cells and enhances their sensitivity to cisplatin

Background

The resistance of melanoma cells to cisplatin restricts its clinical use. Therefore, the search for novel tumor inhibitors and effective combination treatments that sensitize tumor cells to this drug are still needed. We purified macrovipecetin, a novel heterodimeric C-type lectin, from Macrovipera lebetina snake venom and investigated its anti-tumoral effect on its own or combined with cisplatin, in human melanoma cells.

An efficient biocatalytic system for floxuridine biosynthesis based on Lactobacillus animalis ATCC 35046 immobilized in Sr-alginate

An efficient and green immobilized biocatalyst is herein reported to obtain 5-fluorouracil-2′-deoxyriboside (5FUradRib), an antimetabolite known as Floxuridine, used in gastrointestinal cancer treatment.Alginate is a natural polysaccharide used in the pharmaceutical industry due to its physicochemical properties, biocompatibility and non-toxicity. Multivalent cations, exposure time and cross-linking solution concentration were optimized, being Sr²⁺, 2 h and 0.2 M the best immobilization conditions. Furthermore, compression strength, swelling ratio and fracture frequency were evaluated, improving the mechanical stability of the biocatalyst favoring a future scale-up.On the other hand, the reaction parameters for 5FUradRib biosynthesis were optimized in order to obtain an immobilized biocatalyst with enhanced activity. Thus, Lactobacillus animalis ATCC 35046 immobilized in Sr-alginate showed yields of 96% at short reaction times.The obtained biocatalyst was stable for more than 25 days in storage conditions (4 °C) and could be reused at least 10 times without loss of its activity.Additionally, Sr-alginate biocatalyst stability was evaluated in different organic solvents to obtain hydrophobic compounds such as 5-bromouracil-2′-deoxyriboside (5BrUradRib), an effective radiosensitizing agent used in anti-cancer therapy, being hexane the best co-solvent.Finally, a smooth, cheap and environmentally friendly method to obtain anti-cancer drugs was developed in this study.     

Antiproliferative metabolites from the endophytic fungus Penicillium sp. FJ-1 isolated from a mangrove Avicennia marina

Two new compounds, named as 4-(2′,3′-dihydroxy-3′-methyl-butanoxy)-phenethanol (1), and 15-hydroxy-6α,12-epoxy-7β,10αH,11βH-spiroax-4-ene-12-one (2), were isolated from the endophytic fungus Penicillium sp.FJ-1 of Avicennia marina. Their structures were elucidated on the basis of spectroscopic analysis. Additionally, compounds 1 and 2 exhibited antiproliferative activities, and compound 2 significantly inhibited the tumor growth of human xenograft osteosarcoma in nude mice.     

Autophagy-mediated anti-tumoral activity of imiquimod in Caco-2 cells

Imiquimod (IMQ) is recognized as a topical immune response modifier compound that enhances immune responses with anti-viral and anti-tumoral activities. Its anti-tumoral effects have been previously demonstrated in a variety of cancer cells, and were identified as indirect responses mediated by the immune modulation of cutaneous dendritic cells. Recently, the pro-apoptotic activities of IMQ occurring via the modulation of bcl-2 family have been reported in several tumor cells. In this study, we first observed IMQ-initiated autophagy determined by vesicular organelle formation and the generation of LC3-II in Caco-2 human colonic adenocarcinoma cells, which expressing functional TLR7. Additionally, IMQ-induced autophagy resulted in cell death occurring independently of molecular changes of apoptotic markers. Loxoribine also induced autophagy and autophagy-induced cell death at less potent than IMQ. Moreover, the activation of autophagy by rapamycin induced enhanced cell death in TNF-alpha-treated Caco-2 cells, which were autophagy and cell death-resistant. Our results led us to conclude that IMQ exerts a direct effect on the anti-tumoral activity of Caco-2 cells via autophagy-induced cell death. In conclusion, the modulation of autophagy might be applied in a potential cancer therapy for the treatment of colon cancer cells.