Abstract 4463: Metabolic reprogramming through Notch1 signaling promotes a survival advantage in pancreatic neuroendocrine tumor cells

Abstract

Abstract Background: Cancer cells utilize both oxidative phosphorylation (OXPHOS) and glycolysis to generate energy. Switching between OXPHOS and glycolysis can promote tumor progression. The mechanisms governing oncogenic metabolic reprogramming are largely unknown, but recent data has suggested that Notch1 dysregulation in cancer cells can contribute to altered metabolic phenotypes. We hypothesized that Notch1 signaling supports metabolic reprogramming in pancreatic neuroendocrine tumor (pNET) cells. Methods: We established a Notch1-knockout pNET cell line (BON-N1-KO) by deleting Notch1 at exon 3 in a pNET cell line (BON) using CRISPR/Cas9. Proliferation over time was measured using a trypan blue exclusion test. Seahorse Glycolytic Rate Assay and Mitochondria Stress Test were used to measure the glycolytic and mitochondrial activities of cells. A glycolysis deprivation assay was employed to determine cell viability at varying glucose concentrations. Single end RNAseq was performed using the Illumina NGS platform, to a read depth of 50M. Results: Over time, pNET cells lacking Notch1 (BON-N1-KO) proliferated slower than wildtype (WT) cells (p=0.034). Compared to WT BON, the BON-N1-KO cells had reduced basal oxygen consumption rate (28.2 ± 1.3 vs. 40.7 ± 1.4; p=0.02, ATP production (21.9 ± 1.0 vs. 29.6 ± 0.98; p=0.04), and maximal respiration (39.4 ± 1.7 vs. 63.7 ± 2.1; p=0.004). BON-N1-KO cells also had a reduction in basal glycolysis, as measured by proton efflux rate, compared to WT (48.7 ± 2.6 vs. 57.7 ± 6.2; p=0.2). To further test metabolic reprogramming, WT and BON-N1-KO cells were starved of glucose (0mM), compared to normal glucose (17.5mM) and viability was measured over time. By day 5, the BON-N1-KO group had a viability of 0%, whereas 12.8% of WT cells were alive (p=0.038). To determine if Notch1 loss was associated with altered expression of established metabolic genes, we performed RNAseq. Differential gene expression analysis found that OXPHOS-related genes (UQCC2, COX15, COX20) and glycolysis-related genes (Slc1a1, Slc2a4, Hk1, Hk2) were significantly down-regulated in BON-N1-KO cells. Conclusions: Our study shows that Notch1 signaling facilitates metabolic reprogramming as a survival advantage in pNET cells. Targeting Notch1 signaling to mediate cellular metabolism may be a novel therapeutic strategy in pNETs. Citation Format: Rachael Guenter, Weisheng Chen, Brendon Herring, Yuvasri Golivi, Melissa Sammy, Jason Whitt, Renata Jaskula-Sztul, Herbert Chen, J. Bart Rose. Metabolic reprogramming through Notch1 signaling promotes a survival advantage in pancreatic neuroendocrine tumor cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4463.