Ovarian serous cancer tumor microenvironment investigated by MALDI MSI associated to Top-down microproteomic: Evidence of a hidden proteome as novel potential target

ABSTRACT: Top-down tissue microproteomic was performed in order to investigate tumoral tissue microenvironment. 289 proteins with post-translational modifications have been isolated from biospies including Tumor, Borderline and healthy regions of serous ovarian cancers. Tumor tissue displays a majority of proteins from the nucleus and extracellular vesicles. By contrast proteins identified in the healthy tissue or bordeline are related to cellular trafficking and membranes. Global subnetwork analyses confirmed that tumor pathways displayed proteins involved in neoplasm, autophagy, apoptosis, cell proliferation, tumor immunity whereas in healthy tissue pathways are mainly in cell survival, growth, motion, adhesion, differentiation and vascularization. Interestingly, truncated proteins are in majority observed in tumor region reflecting a high level expression of enzymes in this region. Besides the reference proteome, a deeper analysis of the hidden proteome issued from Alternative ORF, led a total of 14 alternative proteins identified i.e. Six Altprot from healthy tissues, 4 from borderline tissues and 4 from tumors. Expression of one of the 4 tumoral alternative protein, AltGNL1 which is translated from an AltORF nested within the GNL1 canonical coding sequence have been performed. Co-expression of annotated and alternative proteins from the same gene, was realized by transfection in HEK 293 and HeLa cells with an expression plasmid containing a GNL1-Flag(V5) construct. Western blot and immunofluorescence experiments with an anti-FLAG confirmed that AltGNL1 is constitutively co-expressed with GNL1. AltGNL1 displays a nuclear localization whereas GNL1 is present in the cytosol. Thus were report here for the first time the co-localization of two proteomes: the one issued from the kozak code and the one from Alternative ORF, so called the Hidden Proteome.

INSTRUMENT(S): Q Exactive

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Ovary

DISEASE(S): Malignant Neoplasm Of Ovary

SUBMITTER: Julien Franck  

LAB HEAD: Michel Salzet

PROVIDER: PXD005420 | Pride | 2017-06-23

REPOSITORIES: Pride