: Magmas, a gene encoding for the mitochondrial import inner membrane translocase subunit, Tim16, protects different cell lines from the antitumoral effects of several pro-apoptotic stimuli (i.e. chemicals and chemotherapeutic agents). The synthetic Compound 5 is capable of sensitizing chemoresistant tumor cells overexpressing Magmas to proapoptotic stimuli, indicating that this molecule may be useful to overcome tumor chemoresistance. The aim of our study was to evaluate whether Compound 5 targets Tim16 and is cytotoxic in vivo. We found that Compound 5 enhances the antiproliferative effects of doxorubicin in MCF7 cells, while it fails to do so in two independent MCF7 cell clones where Magmas was silenced by specific shRNA. Then, the normal breast MCF12 cells were transfected with two differently tagged vectors, tim16-ddktag encoding for Tim16 and tim14-hatag, encoding for its partner Tim14. We found that Tim16 co-immunoprecipitates with Tim14 and that their interaction is reduced in the presence of Compound 5. However, Tim16 levels appear to be reduced in cells treated with Compound 5. The toxicity of this molecule was then tested in vivo by the Fish Embryo toxicity assay, employing Zebrafish eggs: Compound 5 is not toxic in vivo at the concentrations employed in vitro (5 and 10 μM), while its toxicity increases dose-dependently at higher concentrations. These data support the hypothesis that Compound 5 targets Tim16 and that Tim16 levels modulate the chemosensitizing effects of Compound 5, that need to be confirmed by in vivo studies.
20 May 2017 - 23 May 2017