Abstract PO-057: Targeting ErbB2 degradation via the ubiquitin–proteasome pathway to inhibit the metastasis of pancreatic cancer

Abstract Objective: Pancreatic cancer is currently one of the most lethal human cancers and continues to be a major unsolved health problem in the 21st century. Since pancreatic cancer has a high metastatic potential, chemotherapy is inevitable for most pancreatic cancer patients, whereas the clinical responses to anticancer agents are not satisfied. In this work, we designed and synthesized a novel compound, termed as 6-MPA, and found that 6-MPA could improve the proteasomal degradation of ErbB2 pancreatic cancer cells. Methods: The inhibitory effects of 6-MPA on migration and invasion was measured by scratch experiment, wound healing assay and transwell experiment. Clone formation and CCK-8 assay was used to determine the cytotoxicity of 6-MPA. Real-time PCR and western blotting was used to determine the expression of indicated genes or proteins respectively. Immunoprecipitation was used to characterize protein–protein interactions. Results: 4, 8, and 16 μM of 6-MPA exhibited an inhibitory effects on the migration of SW1990 cells and the inhibition rates reached 40.2±10.1%, 58.2±11.2%, and 65.2±9.9% in vitro, respectively. RNA-seq showed that 6-MPA treatment manipulated ErbB2 level and its downstream PI3K/AKT/mTOR signaling pathways, which was verified by western blotting assay. Treatment with 6-MPA could enhance the interaction between ErbB2 and ubiquitin, and thus promote the proteasomal degradation of ErbB2. Conclusion: In this study, we obtained a novel small molecule 6-MPA, which could specifically degrade ErbB2 through the activation of protein ubiquitinination. And we found that 6-MPA possessed potent inhibitory effects on migration and invasion of pancreatic cancer cells. Therefore, our work illustrated a novel structure skeleton that could be used to target ErbB2, and potentially suppressed the metastasis of pancreatic cancer. Citation Format: Bo Zhang, Fei Teng, Nengming Lin. Targeting ErbB2 degradation via the ubiquitin–proteasome pathway to inhibit the metastasis of pancreatic cancer [abstract]. In: Proceedings of the AACR Virtual Special Conference on Pancreatic Cancer; 2021 Sep 29-30. Philadelphia (PA): AACR; Cancer Res 2021;81(22 Suppl):Abstract nr PO-057.