Immunological response in mice bearing LM3 breast tumor undergoing Pulchellin treatment

Background: Ribosome-inactivating proteins (RIP) have been studied in the search for toxins that could be used as immunotoxins for cancer treatment. Pulchellin, a type 2 RIP, is suggested to induce immune responses that have a role in controlling cancer. Methods: The percentage of dendritic cells and CD4+ and CD8+ T cells in the spleen (flow cytometry), cytokines’ release by PECs and splenocytes (ELISA) and nitric oxide production by PECs (Griess assay) were determined from tumor-bearing mice injected intratumorally with 0.1 ml of pulchellin at 0.75 μg/kg of body weight. Statistical analysis was performed by one-way ANOVA with Tukey’s post hoc test. Results: Pulchellin-treated mice showed significant immune system activation, characterized by increased release of IFN-γ and Th2 cytokines (IL-4 and IL-10), while IL-6 and TGF-β levels were decreased. There was also an increase in macrophage’s activation, as denoted by the higher percentage of macrophages expressing adhesion and costimulatory molecules (CD54 and CD80, respectively). Conclusions: Our results suggest that pulchellin is promising as an adjuvant in breast cancer treatment.Fil: de Matos, Djamile Cordeiro. Universidade de Sao Paulo; BrasilFil: Abreu de Ribeiro, Livia Carolina. Universidade de Sao Paulo; BrasilFil: Tansini, Aline. Universidade de Sao Paulo; BrasilFil: Ferreira, Lucas Souza. Universidade de Sao Paulo; BrasilFil: Polesi Placeres, Marisa Campos. Universidade de Sao Paulo; BrasilFil: Colombo, Lucas Luis. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología "Ángel H. Roffo"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Iracilda Zeppone, Carlos. Universidade de Sao Paulo; Brasi

Euphol, a tetracyclic triterpene, from Euphorbia tirucalli induces autophagy and sensitizes temozolomide cytotoxicity on glioblastoma cells

Glioblastoma (GBM) is the most frequent and aggressive type of brain tumor. There are limited therapeutic options for GBM so that new and effective agents are urgently needed. Euphol is a tetracyclic triterpene alcohol, and it is the main constituent of the sap of the medicinal plant Euphorbia tirucalli. We previously identified anti-cancer activity in euphol based on the cytotoxicity screening of 73 human cancer cells. We now expand the toxicological screening of the inhibitory effect and bioactivity of euphol using two additional glioma primary cultures. Euphol exposure showed similar cytotoxicity against primary glioma cultures compared to commercial glioma cells. Euphol has concentration-dependent cytotoxic effects on cancer cell lines, with more than a five-fold difference in the IC50 values in some cell lines. Euphol treatment had a higher selective cytotoxicity index (0.64-3.36) than temozolomide (0.11-1.13) and reduced both proliferation and cell motility. However, no effect was found on cell cycle distribution, invasion and colony formation. Importantly, the expression of the autophagy-associated protein LC3-II and acidic vesicular organelle formation were markedly increased, with Bafilomycin A1 potentiating cytotoxicity. Finally, euphol also exhibited antitumoral and antiangiogenic activity in vivo, using the chicken chorioallantoic membrane assay, with synergistic temozolomide interactions in most cell lines. In conclusion, euphol exerted in vitro and in vivo cytotoxicity against glioma cells, through several cancer pathways, including the activation of autophagy-associated cell death. These findings provide experimental support for further development of euphol as a novel therapeutic agent for GBM, either alone or in combination chemotherapy.The work was supported by the Amazonia Fitomedicamentos (FITO05/2012) Ltda. and Barretos Cancer Hospital, all from Brazil

Avaliação da resposta imune de células dendríticas e subpopulações de linfócitos T no modelo experimental de Yersinia pseudotuberculosis

A infecção por Y. pseudotuberculosis é uma causa de doenças intestinais e extraintestinais. A resolução da infecção está relacionada à ativação de células Th1, entretanto, pouco se conhece sobre a influência de outras subpopulações de linfócitos T, como Th17 e Treg, na regulação dessa infecção. Células dendríticas são capazes de orientar a resposta imune adaptativa através da produção de citocinas e apresentação de antígenos às células T, tornando essas células essenciais na ativação e diferenciação de linfócitos T. Desse modo, o presente trabalho avaliou o papel de distintas subpopulações de linfócitos T e a influência de células dendríticas no desenvolvimento da resposta imune contra a infecção por Y. pseudotuberculosis. Para tanto, foram avaliadas as subpopulações de linfócitos T CD4+, CD8+ e Foxp3+, presentes durante a infecção por Y. pseudotuberculosis e amostras bacterianas mutantes para fatores de virulência Yops, bem como a expressão de citocinas intracelulares (IL-2, IL-4, IL-10, IL-17, IFN-γ, TNF-α e TGF-β) por estas células. O papel de linfócitos Treg e Th17 no controle da bactéria foi analisado por meio de ensaio de depleção de células CD25+ e neutralização de IL-17. Além disso, a influência de células dendríticas na modulação da resposta imune contra Y. pseudotuberculosis foi estudada através da determinação da produção de citocinas (IL-6, IL-12, IL-10, IL-23, TNF-α e TGF-β) e co-cultivo com linfócitos T obtidos de animais imunizados com antígenos de Y. pseudotuberculosis. Os resultados mostraram redução na produção de citocinas pró-inflamatórias por células dendríticas infectadas com a amostra bacteriana portadora do plasmídeo de virulência, em ambas as linhagens de camundongos estudadas...Y. pseudotuberculosis infection is a cause of intestinal and extraintestinal diseases. Infection resolution is related to the activation of Th1 cells, however, little is known about the influence of other T cells subsets, like Th17 and Treg, in the control of this infection. Dendritic cells are capable of directing the adaptive immune response by producing cytokines and presenting antigens to T cells, making them essential to T lymphocytes activation and differentiation. Thus, this study evaluated the role of different T lymphocytes subsets and the influence of dendritic cells on the development of the immune response against Y. pseudotuberculosis infection. Here, we evaluated the T cells subsets CD4+, CD8+ and Foxp3+, present during Y. pseudotuberculosis infection and mutant samples bacterial virulence factors, and also the intracellular expression of cytokines (IL-2, IL-4, IL-10, IL-17, IFN-γ, TNF-α and TGF-β) by these cells. The role of Th17 and Treg cells in controlling the bacteria was analyzed by tests of depleted CD25+ cells and IL-17 neutralization. Furthermore, the influence of dendritic cells in modulating the immune response against Y. pseudotuberculosis was studied by determining the cytokine production (IL-6, IL-12, IL-10, IL-23, TNF-α and TGF-β) and co-culture with lymphocytes from animals immunized with Y. pseudotuberculosis antigens. The results showed a reduction in proinflammatory cytokines production by dendritic cells infected with bacteria carrying the bacterial virulence plasmid, in both mice strains studied... (Complete abstract click electronic access below)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq