8308 Up-regulation of Diacylglycerol kinase gamma (DGKG) in aggressive recurrent pituitary tumors could be targeted by Dasatinib reducing cell proliferation and induced apoptosis
Authors: Taniguchi-Ponciano K , Remba I , Loza-Mejia M , Salazar J , Mendez-Perez A , Aguilar-Flores C , Chavez-Gonzalez A , Ortiz-Reyes E , Bonifaz L , Marrero-Rodríguez D , Mercado M 
Published: October 2024

Disclosure: K. Taniguchi-Ponciano: None. I. Remba: None. M. Loza-Mejia: None. J. Salazar: None. A. Mendez-Perez: None. C. Aguilar-Flores: None. A. Chavez-Gonzalez: None. E. Ortiz-Reyes: None. L. Bonifaz: None. D. Marrero-Rodríguez: None. M. Mercado: None.

Pituitary tumors (PT) represent 15% of all intracranial tumors. Some PTs exhibit an aggressive behavior, growing rapidly and invading surrounding tissues, and are frequently resistant to multimodal treatment showing multiple recurrences. Pituitary tumors often recur after initial surgery, particularly when invasive, precluding complete resection of the lesion, which can only be achieved in ∼40-50% of all patients.We have previously characterized transcriptome and exome from 22 tumor lesions from 11 patients by RNA- and DNAseq and methylome profile by microarrays of aggressive, both primary and recurrent PT from the same patient to identify molecular pharmacological targets.Among the differentially expressed genes in most recurrent tumors we found those related to fatty acid biosynthesis and metabolism, phosphatidylinositol, glycerophospholipid and phospholipase D signaling. Importantly, one gene found in most of the lipid-related pathways was diacylglycerol kinase gamma (DGKG). DGKG gene expression was confirmed by immunofluorescence and did not seem to be regulated by DNA methylation. And DGKG showed allelic c.G947A:p.R316K variant in all primary and recurrent tumor tissues analyzed, more research is needed to understand genetic variant impact on protein function. We then performed DGKG molecular docking for FDA-approved drug repurposing. Human DGKG tridimensional model was downloaded from AlphaFold and Autodock Vina, Molegro Virtual Docker, PyMol v2.5.2 program and the Protein-Ligand Interaction Profiler web tool were used. The in silico ADMET profiles were generated in ADMETLab 2.0 using only FDA approved drugs. We identified Dasatinib as a strong candidate for DGKG targeting. We then exposed GH3 cell line to increasing concentrations of Dasatinib (1, 2.5 y 5 μM) using DMSO as vehicle. After cell viability was assessed, approximatively 31% of all live GH3 cells were at proliferative state without any treatment, that was taken as our basal quantity to compare the GH3 cells treated with the TKI’s. Dasatinib reduced approximatively 28% the cell proliferation at 1 μM (p=0.0048), at 2.5 μM reduced nearly 50% of cell proliferation (p=0.003) and at 5 μM inhibited nearly 98% of cell proliferation (p=0.0395) by means of Click-iT EdU Cell proliferation Kit. We then, evaluated Dasatinib apoptosis induction capacity. Interestingly, the 1 μM Dasatinib concentration induced apoptosis (p=0.0001) as concentrations increased, cell death also increased considerably (p=0.0001) measured by Anexin V-FITC and DAPI assay. The RNAseq data from GH3 cells exposed to Dasatinib show diminished gene expression of cell cycle related genes and glycolysis.In conclusion, we observed DGKG upregulated in recurrent aggressive pituitary tumors participating in lipid metabolism pathways and could be targeted by Dasatinib at very low doses.

Presentation: 6/3/2024