Poster Presentation HUPO 2019 - 18th Human Proteome Organization World Congress

Genomic deletion of siat8 induces mesenchymal-to-epithelial transition in ovarian cancer cells (#486)

Cécile Cumin 1 , Yen-Lin Huang 1 , Charlotte Rossdam 2 , Natalie Rimmer 1 , Ching-Yeu Liang 1 , Monica Lopez 1 , André Fedier 1 , Viola Heinzelmann-Schwarz 3 , Falk Büttner 2 , Francis Jacob 1
  1. University of Basel - University Hospital Basel, Basel, BASEL STADT, Switzerland
  2. Department of Biochemistry, Institute of Clinical Biochemistry, Hannover, Germany
  3. Department of Gynecology and Gynecological Oncology , Hospital for Women, Univeristy Hopsital of Basel , Basel Stadt , Basel , Switzerland

Ovarian cancer cells need to undergo reversible epithelial-to-mesenchymal transition (EMT/MET) to invade the surrounding organs of the peritoneal cavity.
During this transition, cancer cells also change their glycosphingolipids (GSLs) repertoire. Previous studies in our laboratory have demonstrated that depletion
of globosides (ΔA4GALT) induce EMT and increase gangliosides expression in ovarian cancer cells [1,2]. However, role of GSLs in MET promoting formation
of primary tumor and metastic growth are still uncertain. Thus, we generated ovarian cancer cell lines homozygously deleted for SIAT8 using the
CRISPR-Cas9 technology.To the GSL content in our knockout cell lines, we used the capillary gel electrophoresis coupled to laser-induced fluorescence detection
(xCGE-LIF) [3]. Here, the mean migration time (MTU) of 13.61 corresponding to the ganglioside GT3 was reduce in ΔSIAT8 cells. Interestingly, depletion of ΔSIAT8 cells
revealed an increase of globosides Gb3 (MTU: 80.56) compared with the wild-type.Trough in vitroand in vivoassays, we already observed that deletion of SIAT8 reduces
the cell capacity to invade and migrate (p< 0.05) but increase their competences to form spheroids in 3D cultures and tumor growth in tumor xenografts. Moreover, in
the aim to understand regulation of these cellular processes we performed (phospho-) proteomic analysis and identified 11342 phosphorylation sites with 84 up-regulated
and 223 down-regulated in SKOV3 ΔSIAT8. Bioinformatic analysis identified down-phosphorylated peptides such as MTOR, MAPK1, CTNBB1, and JUN, enzymes which are
related in cancer and MAP Kinase pathway. Specifically, we confirmed decrease of Erk1/2 phosphorylation by Western blot, known to be implicated as an EMT driverwhile
proteins such as ERBB2 usually involved in tight junction pathway were enriched. Here, we provide the first evidence that GSLs play an important role in EMT/MET and
that the regulation of gangliosides GSLs expression is an important driver of EMT-associated pathways

  1. 1. Jacob et al., 2018 Cancer Research 78(11): 2952-2965 2. Alam et al., 2017 Scientific Reports 7: 45367 3. Rossdam et al., 2019 Anal. Chem. 91(10) : 6413-6418