University of Maryland School of Medicine Baltimore, MD
J. H. Chang1, D. D. Chowdhury2, D. N. Council1, T. M. Nguyen3, S. Jagtap4, A. Chan1, M. Ajmal Khan1, N. Connis5, P. Torres-Ayuso6, J. Brognard7, M. Rezaee8, A. Lafargue1, C. L. Hann5, and P. T. Tran1; 1University of Maryland Baltimore, School of Medicine, Baltimore, MD, 2Department of Radiation Oncology, Division of Translational Radiation Sciences, University of Maryland Baltimore, School of Medicine,, Baltimore, MD, 3Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 4Johns Hopkins University School of Medicine, Baltimore, MD, 5Johns Hopkins University, School of Medicine, Baltimore, MD, 6Lewis Katz School of Medicine at Temple University, Philadelphia, PA, 7National Cancer Institute, Frederick, MD, 8Department of Radiation Oncology and Molecular Radiation Sciences, School of Medicine, Johns Hopkins University, Baltimore, MD
Purpose/Objective(s): Lung squamous cell carcinoma (LSCC) is the second most prevalent type of lung cancer with no FDA-approved targeted therapies. Platinum-based chemotherapy and immunotherapy remain the cornerstone of current treatments for advanced LSCC, and the 5-year survival rate is less than 10%. Amplification of chromosome 3q26 is the most common genomic alteration in LSCC and this leads to the overexpression of oncogenic kinases like TNIK. TNIK amplification occurs in approximately 40% of LSCC cases and is associated with tumorigenesis and therapy resistance in other cancers. However, the role of TNIK in LSCC tumorigenesis and therapeutic potential is largely unexplored. Genetically engineered mouse models (GEMMs) are a gold standard in studying tumor progression in vivo, but the development of GEMMs for LSCC has been challenging due to its complex genetics as no single driver oncogene has been validated in LSCC. Deletion of Fbxw7 with simultaneous activation of KrasG12D (KF model) generates both lung adenocarcinoma and LSCC within 9-12 weeks. Our goal was to generate a novel conditional Tnik-overexpressing LSCC mouse model to better understand the role of TNIK in tumor progression and therapy resistance in LSCC and elucidate mechanisms underlying LSCC pathogenesis. Materials/
Methods: We created a novel conditional Tnik-overexpressing genetically engineered mouse model (GEMM) where Tnik overexpression can be induced by Cre-recombinase. We are crossing our novel Tnik-overexpressing GEMM to KF model of mixed adenocarcinoma and LSCC lung tumors to generate Tnik-overexpressing LSCC GEMM. Results: Mouse Tnik cDNA was placed under the control of a CAG promoter to ensure strong ubiquitous expression in vivo. A loxP-flanked Stop cassette was inserted between the promoter and Tnik. In addition, the tdTomato fluorescent reporter gene was placed downstream following an IRES element. This entire transgene was inserted into the Rosa26 locus using the Rosa Quick Knock-in™ technology and the targeting vector was transfected following electroporation into ES cells. Selected ES cell clones were assessed by PCR and sequencing validated the correct recombination event and were injected in blastocysts to generate highly chimeric males (chimerism rate above 50%). Germline transmission was confirmed, and Tnik-overexpression was confirmed in vivo in a Cre recombinase-specific fashion. We will present validation studies such as histological and molecular profiling of our conditional Tnik-overexpressing GEMM and initial data on the Tnik-overexpressing LSCC GEMM. Conclusion: One major limitation for therapeutic development in LSCC is the lack of animal models with pure squamous histology and patient relevant mutant genotypes. Our novel Tnik-overexpressing GEMM will help us to understand better the biology of LSCC and provide new potential treatment options for LSCC.
