Abstract 2977: Profiling oncogenic Ras mutant drugs with homogeneous bioluminescent immunoassays

Abstract Activating KRAS mutations present in many cancers are difficult to target with drugs until recently with the FDA approval of sotorasib (AMG-510), a KRAS G12C selective inhibitor. In an effort to study Ras inhibitors in cells and identify new compounds that inhibit Ras and its downstream signaling, assays such as western or ELISA are commonly used. These traditional immunoassays can be tedious, require multiple washing steps, and are not easily adaptable to a high throughput screening (HTS) format. To overcome these limitations, we developed Lumit, a novel immunoassay approach that combines bioluminescent enzyme subunit complementation technology and immunodetection. We applied this bioluminescent and homogeneous “Add and Read” assay to analyze Ras signaling pathway activation and inhibition through multiple nodes of the pathway including detection of phosphorylated ERK. The assay was used to profile different allele specific inhibitors with cell lines harboring different activating KRAS mutations and obtained the predicted pharmacology and selectivity. The potency of PROTAC compound targeting selective degradation of KRAS G12C was also tested using Lumit and the result showed that maximal decrease in RAS signaling was achieved. Unlike current assays that require lengthy sample preparation and multiple washing steps, the Lumit immunoassay provides an alternative platform because it is homogeneous and allows to decipher signaling pathways activities in a fast and simple manner. Our results demonstrate that this bioluminescent technology can be adapted to any signaling pathway node, allowing scientists to streamline the analysis of signaling pathways of interest such as Ras, and identify much needed inhibitors of its mutants. Citation Format: Hicham Zegzouti, Laurie Engel, Matthew Swiatnicki, Juliano Alves, Said A. Goueli. Profiling oncogenic Ras mutant drugs with homogeneous bioluminescent immunoassays [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2977.