IMPLICATIONS OF THE HEME-OXYGENASE 1 (HO-1) INTERACTOME IN THE CYTOSKELETON REPORGRAMING OF PROSTATE CANCER CELLS: TOWARDS AN EPITHELIAL-LIKE MORPHOLOGY

PAEZ ALEJANDRA; PALLAVICINI CARLA; GIUDICE JIMENA; LABANCA ESTEFANIA; ANSELMINO NICOLAS; ORTIZ EMILIANO GERMAN; SCHUSTER FEDERICO; BRUNO LUCIANA; LEVI VALERIA; NAVONE NORA; VAZQUEZ ELBA; GUERON GERALDINE

Congreso; The Third South American Symposium in Signal Transduction and Molecular Medicine; 2015

Cellular motility is a coordinated process that involves variations in the dynamics of the actin cytoskeleton and its interplay with focal adhesions. The re-arrangement of actin and its attachment to focal adhesions at the leading edge of a migrating cell generates the driving force necessary for movement. The loss of cell-cell adhesion enables cancer cells to dissociate from the primary tumor mass and allows the cells to invade the surrounding stroma. Heme oxygenase-1 (HO-1) plays a critical role in prostate cancer (PCa), impairing cell proliferation, migration, invasion and modulating cellular adhesion. We began to screen HO-1 molecular partners through a proteomics and bioinformatics approach, to determine the molecular mechanisms by which HO-1 regulates cell morphology, quantify and compare microtubule and actin dynamics at the leading edge level in PCa cells. FLAG immunoprecipitation assays were performed using lysates from PC3 cells transfected with FLAG-tagged HO-1, and the isolated proteins were subjected to LC/ESI-MSMS analysis. Protein interaction network and gene ontology analyses of HO-1 interacting proteins showed enrichment of proteins associated with the cytoskeleton organization, transportation and membrane bounding. To quantify contacts among cells, PC3 cells were exposed to hemin (a pharmacological inducer of HO-1, 80μM, 24h), fixed and stained with phalloidin-rhodamin. We selected regions in which the filopodia from two neighboring cells touched each other, considered as ?contacts?. An intensity profile for each of these sectors was analyzed with a custom made algorithm to count contacts. A significant higher proportion of filopodia-like protrusions among neighboring cells and increased cellular contact were observed under HO-1 modulation. These results show that HO-1 modulation in PCa induces the remodeling of the actin filament architecture at filopodia, altering cellular morphology, towards a less aggressive phenotype.