Abstract 799: Aberrant mitochondrial protein involvement through early PDAC initiation and progression using multiplexed DNA-PAINT and correlative histology

Abstract

Abstract Prior to pancreatic ductal adenocarcinoma (PDAC), pancreatic acini cells change their morphology through pancreatic intraepithelial neoplasia (PanIN) stages, becoming increasingly dysplastic as stroma and tissue hypoxia increase. This increasing hypoxia forms a cancer promoting microenvironment, wherein we propose metabolic changes trigger aberrant mitochondrial networks form healthy tissue. We developed tissue superresolution imaging to directly quantify structural mitochondrial response through patient histology, whereby DNA-PAINT can provide super-resolution detail decoupled from photo bleaching to visualize mitochondria through tissue layers. Expanding from preliminary data, target mitochondrial dynamics proteins’ organization will also be correlated to PanIN stages. Introduction: Early oncogene involvement in PDAC progression links to metabolic and mitochondrial regulatory changes. Typically nutrient deprivation and hypoxia trigger cell death from increased reactive oxygen species production and organelle damage which trigger apoptosis, yet these prolonged effects can be cancer promoting when less severe. Mitochondrial dynamics and proteins related to mitochondrial fission and fusion can reduce apoptotic signaling, enhance aerobic glycolysis, and increase ROS to allow cancer progression. Materials and Methods: Adapting from previous proof of concept, mitochondria (TOM20) within formalin-fixed paraffin embedded (FFPE) tissue sections were imaged with stochastic optical reconstruction microscopy (STORM). In brief: cadaver healthy pancreas FFPE tissue samples underwent deparafinization, antigen retrieval, indirect immuno-labeling with AlexaFluor647, TIRF illumination with a 60x objective was used for data collection, whereby data processing was conducted using the open-source FIJI and custom MATLAB software. Results and Discussion: Preliminary data shows proof of principle that both STORM and DNA-PAINT can be correlated to histological staining of human pancreas. Conclusions: Superresolution imaging reveals ultrastructural details of mitochondria in FFPE patient samples not resolved via conventional fluorescence imaging. Through quantitative feature analysis, we would be able to correlate aberrant mitochondria structure and abundance to PDAC progression. Acknowledgements: Funding provided by the Cancer Early Detection Advanced Research (CEDAR) Center of OHSU Knight Cancer Institute. Citation Format: Matthew J. Rames, Fehmi Civitci, Ting Zheng, Josiah Wagner, Jason Link, Xiaolin Nan. Aberrant mitochondrial protein involvement through early PDAC initiation and progression using multiplexed DNA-PAINT and correlative histology [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 799.