Evaluation of isoform specific AKT inhibition in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) has the worst prognosis of all tumor entities due to early metastasis and high intrinsic resistance to chemo-, radio- and immunotherapy. AKT may play a role in the development of this resistance. Physiologically, the serine/threonine kinase is involved in several anabolic pathways. Three AKT isoforms have been characterized to date, two of which are relevant in the pancreas. The aim of the project was to characterize the specific functions of AKT1 and AKT2 in PDAC cell lines and investigate selective inhibition with regards to cytotoxic and metabolic effects. For this purpose, highly selective covalent-allosteric inhibitors were used in addition to genetic inactivation of AKT1 or AKT2 using CRISPR/Cas9. After successful and selective knockout, the isoform-specific effect of AKT expression and some downstream targets were examined. In addition, the selective inhibitors were tested on the PDAC cell lines to investigate their effectiveness and modulate combinatory treatment strategies. Although the knockout of AKT1 and AKT2 proved to be successful for five cell lines (PSN1, PANC1, HPAC, HupT4, and HPDE), the effects on the cells remained small. Neither the growth rate of the cells nor the phosphorylation pattern was significantly affected by the knockout of one AKT isoform. Both control and knockout cell lines have shown very high intrinsic resistance to different drugs against AKT, PI3K and MEK. All performed experiments impressively demonstrated the adaptability and danger of pancreatic cancer.