title: GD2 ganglioside specific antibody treatment downregulates PI3K/Akt/mTOR signaling network in human neuroblastoma cell lines.
abstract: Mechanisms leading to inhibitory effects of an anti-GD2 ganglioside (GD2) 14G2a mouse monoclonal antibody (mAb) and PI3K/Akt/mTOR pathway inhibitors on human neuroblastoma cell survival were studied in vitro. We have recently shown on IMR-32, CHP‑134, and LA-N-1 neuroblastoma cells that targeting GD2 with the mAb decreases cell viability of the cell lines. In this study we used cytotoxicity assays, proteomic arrays and immunoblotting to evaluate the response of the three cell lines to the anti‑GD2 14G2a mAb and specific PI3K/Akt/mTOR pathway inhibitors. We show here that the mAb modulates intracellular signal transduction through changes in several kinases and their substrates phosphorylation. More detailed analysis of the PI3K/Akt/mTOR pathway showed significant decrease in activity of Akt, mTOR, p70 S6 and 4E-BP1 proteins and transient increase in PTEN (a suppressor of the pathway), leading to inhibition of the signaling network responsible for stimulation of translation and proliferation. Additionally, combining the GD2-specific 14G2a mAb with an Akt inhibitor (perifosine), dual mTOR/PI3K inhibitors (BEZ-235 and SAR245409), and a pan-PI3K inhibitor (LY294002) was shown to enhance cytotoxic effects against IMR-32, CHP‑134 and LA-N-1 cells. Our study extends knowledge on mechanisms of action of the 14G2a mAb on the neuroblastoma cells. Also, it stresses the need for further delineation of molecular signal orchestration aimed at more reasonable selection of drugs to target key cellular pathways in quest for better cure for neuroblastoma patients.
authors.affiliation: Laboratory of Molecular Genetics and Virology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland.
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Durbas
authors.affiliation: Laboratory of Molecular Genetics and Virology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland.
authors.forename: Irena
authors.initials: I
authors.lastname: Horwacik
authors.affiliation: Laboratory of Molecular Genetics and Virology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland.
authors.forename: Elżbieta
authors.initials: E
authors.lastname: Boratyn
authors.affiliation: Laboratory of Molecular Genetics and Virology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland.
authors.forename: Elżbieta
authors.initials: E
authors.lastname: Kamycka
authors.affiliation: Laboratory of Molecular Genetics and Virology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland.
authors.forename: Hanna
authors.initials: H
authors.lastname: Rokita
mesh_terms: D000911:Antibodies, Monoclonal / Q000494:pharmacology*; D017209:Apoptosis; D045744:Cell Line, Tumor; D004357:Drug Synergism; D005732:Gangliosides / Q000037:antagonists & inhibitors*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D009447:Neuroblastoma / Q000188:drug therapy* / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010767:Phosphorylcholine / Q000031:analogs & derivatives / Q000494:pharmacology; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D011804:Quinolines / Q000494:pharmacology; D011810:Quinoxalines / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects*; D013449:Sulfonamides / Q000494:pharmacology; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D005732:Gangliosides; D007093:Imidazoles; D019869:Phosphatidylinositol 3-Kinases; D010767:Phosphorylcholine; D051057:Proto-Oncogene Proteins c-akt; D011804:Quinolines; D011810:Quinoxalines; D013449:Sulfonamides; D058570:TOR Serine-Threonine Kinases; C576808:XL765; C105905:perifosine; C019403:ganglioside, GD2; C546842:MTOR protein, human; C531198:dactolisib