The Role of Protein Kinases in NRF2-driven Lung Squamous Cell Carcinoma

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Project Summary Despite the dismal prognosis for patients with advanced lung squamous cell cancer (LUSC), few effective treatments of only limited benefit exist. Cytotoxic therapy with radiation remains the mainstay for most patients. However, it carries a relatively narrow therapeutic index and patients invariably suffer treatment-related systemic toxicities. The development of new targeted therapies for LUSC remains a high priority. One of the most significant discoveries from lung cancer genome sequencing is the frequent (~30%) alterations of the KEAP1- NRF2 signaling pathway. The NRF2 antioxidant signaling pathway constitutes the primary cellular defense system against oxidative stress. Several mechanisms responsible for governing NRF2 activity are known, however they have proven largely intractable for therapeutic intervention (eg. transcription factors). Recent studies have revealed that several protein kinases functionally impact NRF2, although a global evaluation of how the kinome instructs NRF2 biology remains untested. Being among the most druggable of protein classes, kinases and phosphatases offer attractive targets for NRF2-directed treatment intervention. Our preliminary data have established reciprocal communication between NRF2 and protein kinases, including upstream modifiers and downstream effectors. Therefore, we hypothesize that the kinome encompasses key regulators of NRF2 signaling and holds novel therapeutic targets for NRF2-active lung cancer. We have assembled a unique multidisciplinary team of investigators with experience in LUSC molecular signaling, cancer cell biology, animal and cell culture models, proteomics, and clinical therapeutics to decipher the interactions between the kinome and NRF2 signaling, identify novel therapeutic targets and analyze them in pre-clinical models. Our specific aims include: (1) IDENTIFY KINASES THAT REGULATE NRF2; (2) IDENTIFY NRF2-RESPONSIVE KINASES AND PHOSPHATASES; and (3) EVALUATE KINOME FUNCTION IN NOVEL MODELS OF NRF2 ACTIVE LUSC. This project shows strong innovation through kinome proteomic profiling of LUSC tumor samples and cell lines, high-throughput chemical screens, gain- and loss-of-function genetic screens, and the application of unique 2- and 3-dimensional cell culture models. Our experiments employ gene targeted-transformation of human bronchial epithelial cells and novel genetically engineered mouse models and derived cell lines. The results of this work will reveal protein kinases that functionally impact NRF2 biology, and in doing so may lead to new effective treatments for LUSC and other NRF2-active tumors, including head and neck cancer, bladder cancer, and ovarian cancer. Ultimately, the successful completion of our proposed studies will provide a roadmap for similar efforts on targeted therapeutic discovery in these other human malignancies.