Super-Resolution Imaging of Higher-Order Heterochromatin Structure for Early Detection of Lung Carcinogenesis

Lung cancer is the leading cause of cancer-related death in the United States. Overall, patients diagnosed with early-stage lung cancer have a much better prognosis. Cigarette smoking is the major cause of lung cancer and screening for lung cancer is currently recommended for high-risk current and former smokers. Compared with nonsmokers, smokers have an almost 30-fold increased risk of developing lung cancer. Unfortunately, despite significant efforts, early detection of lung cancer remains sub-optimal with conventional approaches suffering from high false-positive rates or limited sensitivity. Improved understanding of the early events underlying smoking-related lung cancer development is crucial to the identification of new biomarkers and targets for early detection and prevention. Further, new methods that detect those early events in lung cancer development in a non-invasive and cost-effective manner with high sensitivity and specificity are urgently needed. Recent advances in super-resolution microscopy revolutionize the field of optical microscopy and offer a new ability to visualize molecular structure at nanometer resolution that is invisible under a conventional light microscope. We propose an innovative approach to adapt super-resolution microscopy to improve the early detection of lung cancer. Our approach is built upon our recent discovery that chromatin folding becomes gradually fragmented in early lung carcinogenesis, even when cells still appear normal under conventional light microscope. Our ultimate goal is to detect such nanoscale chromatin “misfolding” in bronchial cells present in sputum to improve early detection of lung cancer. In this project, we will first establish disrupted nanoscale chromatin folding as an early event in lung carcinogenesis utilizing a mouse model of carcinogen-induced lung adenocarcinoma as well as existing well-annotated human lung tissue specimens (Aim 1). In addition, we will evaluate the feasibility of super-resolution imaging of nanoscale chromatin “misfolding” for early detection of lung cancer using existing sputum samples and data from the Pittsburgh Lung Screening Study, a communitybased research cohort of current and ex-smokers, screened with low-dose computed tomography and followed for lung cancer (Aim 2).