Title: Kinase-Modulated Bioluminescent Indicators Enable Noninvasive Imaging of Brain Permeability and Pharmacodynamics of Kinase-Targeting Drugs

Abstract: Aberrant kinase activity is a hallmark of many cancers, and kinase inhibitors have emerged as effective drugs in cancer therapy by targeting the dysregulated kinases. However, developing kinase inhibitors that can function effectively in the brain remains challenging because the blood-brain barrier (BBB) restricts the entry of most compounds. Furthermore, a thorough understanding of the pharmacodynamics (PD) of kinase inhibitors is essential for their rational design, optimization, and successful clinical application. Traditional methods for evaluating drug permeability across the BBB and assessing PD rely on tissue dissection followed by biochemical analysis, a process that is time-consuming, labor-intensive, and requires one mouse per data point.

In my thesis, I developed kinase-modulated bioluminescent indicators (KiMBIs) based on the NanoLuc luciferase for noninvasive and real-time imaging of brain permeability and PD of kinase-targeting drugs. Specifically, I engineered the first bioluminescent indicator for ERK, termed ERK KiMBI, and established a novel platform to evaluate the brain activity of MEK/ERK inhibitors. ERK KiMBI effectively distinguishes brain-permeable from non-permeable MEK inhibitors, leading to the identification of temuterkib as the first brain-active ERK inhibitor. Additionally, I developed Akt KiMBI for noninvasive assessment of drug PD in both the brain and body, enabling rapid structure-PD relationship analysis of Akt inhibitors and revealing the prolonged PD effect of an Akt PROTAC degrader compared to traditional Akt inhibitors. Moreover, I demonstrated the versatility of KiMBI by successfully adapting KiMBIs for a range of kinases, including PKA, mTOR, p38, and LRRK2. We believe that the KiMBI technology will significantly facilitate the discovery of effective cancer therapies targeting aberrant kinase signaling.

Please contact Madelyn Bernstein for the Zoom link