Transforming growth factor (TGF)-beta is a secreted multifunctional cytokine that signals via plasma membrane TGF-beta type I and type II receptors and intercellular SMAD transcriptional effectors.... Show moreTransforming growth factor (TGF)-beta is a secreted multifunctional cytokine that signals via plasma membrane TGF-beta type I and type II receptors and intercellular SMAD transcriptional effectors. Aberrant inter- and intracellular TGF-beta signaling can contribute to cancer progression. In normal cells and early stages of cancer, TGF-beta can stimulate epithelial growth arrest and elicit a tumor suppressor function. However, in late stages of cancer, when the cytostatic effects of TGF-beta in cancer cells are blocked, TGF-beta signaling can act as tumor promoter by its ability to stimulate epithelial-to-mesenchymal transition of cancer cells, by stimulating angiogenesis, and by promoting evasion of immune responses. In this review, we will discuss the rationale and challenges of targeting TGF-beta signaling in cancer and summarize the clinical status of TGF-beta signaling inhibitors that interfere with TGF-beta bioavailability, TGF-beta/receptor interaction, or TGF-beta receptor kinase function. Moreover, we will discuss targeting of TGF-beta signaling modulators and downstream effectors as well as alternative approaches by using promising technologies that may lead to entirely new classes of drugs. Show less
Demarta-Gatsi, C.; Rivkin, A.; Bartolo, V. di; Peronet, R.; Ding, S.; Commere, P.H.; ... ; Mecheri, S. 2019
Protozoan pathogens secrete nanosized particles called extracellular vesicles (EVs) to facilitate their survival and chronic infection. Here, we show the inhibition by Plasmodium berghei NK65 blood... Show moreProtozoan pathogens secrete nanosized particles called extracellular vesicles (EVs) to facilitate their survival and chronic infection. Here, we show the inhibition by Plasmodium berghei NK65 blood stage-derived EVs of the proliferative response of CD4(+) T cells in response to antigen presentation. Importantly, these results were confirmed in vivo by the capacity of EVs to diminish the ovalbumin-specific delayed type hypersensitivity response. We identified two proteins associated with EVs, the histamine releasing factor (HRF) and the elongation factor 1 alpha (EF-1 alpha) that were found to have immunosuppressive activities. Interestingly, in contrast to WT parasites, EVs from genetically HRF- and EF-1 alpha-deficient parasites failed to inhibit T cell responses in vitro and in vivo. At the level of T cells, we demonstrated that EVs from WT parasites dephosphorylate key molecules (PLC gamma 1, Akt, and ERK) of the T cell receptor signalling cascade. Remarkably, immunisation with EF-1 alpha alone or in combination with HRF conferred a long-lasting antiparasite protection and immune memory. In conclusion, we identified a new mechanism by which P. berghei-derived EVs exert their immunosuppressive functions by altering T cell responses. The identification of two highly conserved immune suppressive factors offers new conceptual strategies to overcome EV-mediated immune suppression in malaria-infected individuals. Show less
Spel, L.; Boelens, J.J.; Steen, D.M. van der; Blokland, N.J.G.; Noesel, M.M. van; Molenaar, J.J.; ... ; Nierkens, S. 2015
