LAUSR

KRAS is frequently mutated in pancreatic ductal adenocarcinoma (PDAC). However, targeting mutant KRAS is still challenging. Kinase inhibitors are ideal targeted therapeutics for mutant KRAS-driven cancer. In our previous study, an esiRNA screening was prepared to identify some vital kinases that took part in KRAS mutant-driven pancreatic cancer. The STK31 was identified as a potential therapeutic target in KRAS mutant PDAC. This study aimed to investigate the underlying mechanism of STK31 in KRAS mutant PDAC as well as its therapeutic potential. The results demonstrated that STK31 was upregulated in KRAS mutant PDAC patients with poor survival. STK31 was also highly expressed in PDAC cell lines with KRAS mutant background. Inhibition of STK31 in KRAS mutant cell lines significantly reduced PDAC cell proliferation, colony formation, and migration. Gain and loss of function experiments revealed that STK31 was a downstream target of KRAS in PDAC. Pharmacological inhibition of several signaling pathways involved in KRAS showed MAPK/ERK signaling involved in STK31 regulation. Then, further mechanistic study validated that c-Jun, regulated by KRAS/MAPK/ERK signaling, directly regulated the transcription level of STK31 by binding to its promoter region. In summary, our results show that STK31 promotes PDAC cell proliferation under the control of the KRAS/MAPK/ERK/c-Jun transcriptional axis in PDAC. STK31 may act as a potential target in PDAC treatment. Citation Format: Yuting Liu, Shing Chun Tang, Yangchao Chen. The molecular mechanism underlying KRAS regulation on STK31 expression in pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2218.