Internalization and intracellular trafficking of an antitumor molecule

Abstract

Amblyomin‐X is a proteasome inhibitor that was identified through the transcriptome analysis of the salivary gland from Amblyomma sculptum tick. This recombinant protein triggers apoptosis in different tumor cell lines, and promotes regression of tumor growth and reduction of metastasis. Recent studies have indicated endocytosis mechanism could be associated with pro‐apoptotic activity of this protein. Here, by using confocal microscopy and high content analysis (ImageXpress Micro Confocal High‐Content, Molecular Devices), we found that Amblyomin‐X (Alexa Fluor 488 conjuaged) preferentially co‐localize with Alexa Fluor 555 Cholera Toxin Subunit B, caveolin‐1 and 19S proteasome subunit in human tumor cells (SK‐MEL‐28 and MIA PaCa‐2). Remarkably, we identified Amblyomin‐X co‐immunoprecipitates with caveolin‐1 and Rab‐11. Also, we observed an alteration in Ambyomin‐X trafficking in human tumor cells transfected with GFP‐Rab5 mutants (Rab5:Q79L and Rab5:N133I). Taken all results together, we can suggest that Amblyomin‐X internalization occurs via lipid raft pathway and intracellular trafficking involved of caveosomes and early and recycling endosomes. Then, Amblyomin‐X reaches proteasome system, a possible intracellular destination.Support or Funding InformationSupported by CAPES, Fapesp, BNDES and União Química FarmacêuticaThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.