Abstract C51: Targeted inhibition of DUSP1 and DUSP6 suppresses pancreatic adenocarcinoma cells’ growth and glucose metabolism via SAPK/JNK pathway activation
Authors: Andrade Pamela V. , Ruckert Mariana T. , Junior Carlos Alberto O. Biagi , Silveira Vanessa S. 
Published: March 2020

Abstract
The highly malignant potential and aggressiveness of pancreatic adenocarcinoma cells is mainly promoted by oncogenic KRAS activation, which triggers numerous signaling pathways and controls key processes for tumor progression such as cell survival and metabolic reprograming. The major adjustments in metabolic reprogramming mediated by KRAS activity are controlled by MAP kinase activities, which are precisely regulated by protein phosphatases to coordinate complex signaling networks. The major class of phosphatases controlling MAPKs is represented by dual-specificity protein phosphatases (DUSPs). As DUSPs’ role in PDAC cells remains to be elucidated, here we investigated the impact of DUSPs on PDAC chemoresistance and metabolic reprogramming. PDAC cell lines (MIA PaCa-2 and PANC-1) stably expressing the Cas9 endonuclease were submitted to CRISPR using an Edit-R library (GE Dharmacon) of crRNAs targeting all DUSP genes with 3 crRNAs per gene. Phenotypic analysis was conducted to address PDAC cells’ glucose uptake and identify the most relevant targets. Glucose uptake and lactate production were performed by flow cytometry and colorimetric assay, respectively. DUSP1 and DUSP6 were inhibited through a pharmacologic and genetics approach. Gemcitabine response was performed in a 4-day MTT assay. In vitro assays such as cell viability, apoptosis, colony-forming assay, ROS production, glucose uptake rate, and protein expression were performed in three independent experiments. For gene expression, a PCR array with a set of 92 glucose metabolism-related genes has been performed. RNAseq data from pancreatic adenocarcinoma (data generated by the TCGA Research Network: http://cancergenome.nih.gov/) was analyzed by using the LinkedOmics platform (Vasaikar S, 2017). Among the whole DUSP family members, CRISPR screening revealed DUSP1 and DUSP6 as the major players in glucose uptake control in PDAC cell lines. BCI (inhibitor of DUSP1 and DUSP6) treatment of PDAC cells significantly modulated glucose uptake rates (p&lt;0.002) and drastically reduced cell viability and survival (p&lt;0.003), followed by a reduction in reactive oxygen species (ROS) production (p&lt;0.05). DUSP1 and DUSP6 inhibition also provoked an increase on apoptosis (p&lt;0.001) and sensitized cells to gemcitabine DUSPs inhibition by BCI promoted JNK activation but did not impact other MAPKs’ activity. Interestingly, we identified a differential gene expression signature of glucose metabolism and TCA cycle in both PCR array upon DUSP1 and DUSP6 modulation and from analysis of PDAC-TCGA data. Taken together, these data suggest that DUSP1 and DUSP6 may play an important role on PDAC cell survival through glycolytic and TCA cycle intermediates’ modulation. Additionally, these data point to BCI as a potential drug strategy to PDAC, which brings additional information to contribute to therapeutic target possibilities against this dismal disease.
Citation Format: Pamela V. Andrade, Mariana T. Ruckert, Carlos Alberto O. Biagi Junior, Vanessa S. Silveira. Targeted inhibition of DUSP1 and DUSP6 suppresses pancreatic adenocarcinoma cells’ growth and glucose metabolism via SAPK/JNK pathway activation [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2019 Sept 6-9; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2019;79(24 Suppl):Abstract nr C51.