Development and Characterization of Clinically Relevant Non‐Small Cell Lung Cancer Mouse Model with Near‐Infrared Fluorescent 3D Spheroids

Background Lung cancer claims the highest mortality among all cancers in the US and leads the development of new cancer cases in developing countries. Pre‐clinical mouse models hold an essential role in guiding the development of new therapeutics for lung cancer [1]. Injection of suspended cancer cells into the lung is one of the most common approaches to build an orthotopic lung cancer model, but carries several major disadvantages, including the omission of a primary solid tumor and the artificial leakage of the injected cancer cells [2][3]. These drawbacks limit the application of such model in evaluating potential therapeutics for metastasized lung cancer. Herein, tumor spheroids were injected transpleurally to develop an orthotopic lung cancer model in mice, which then progressed through all the four clinical stages of non‐small cell lung cancer. Moreover, the near‐infrared fluorescent signal of the tumor cells allows efficient and convenient tracking of the cancer progression compared to traditional imaging methods, such as CT/PET and bioluminescence. Purpose The purpose of this study is to build a more clinically relevant, orthotopic lung cancer model by inoculating 3D spheroids of lung cancer cells into the mouse lung. Method The 3D spheroids were cultured by seeding human lung cancer cell line A549‐iRFP in Corning 96 multicellular microplate. The cells stably expressed infrared fluorescent protein, whose signal was detected on an Odyssey CLx imaging machine (lex = 690 nm, lem = 700 nm) to image the tumor growth in vivo . Tumor inoculation was performed by transpleural surgery on the left side of the athymic nude mice. Results The fluorescence of the spheroids was proportional to their volume and viability (R 2 =0.9805 and 0.9191). The mice implanted with tumor spheroid showed tumor growth confined to the inoculation side of the lung. Furthermore, the in vivo imaging showed cancer development from a primary tumor to metastasis within one month. The anatomical observations and ex vivo imaging confirmed the tumor location. In comparison, mice that were injected with suspended cancer cells displayed perfused the fluorescent signal on both sides of the lung indicating premature leakage of the inoculated cancer cells. Conclusion The mice inoculated with suspended cancer cells displayed artificial leakage of the injected cells inside the lung, which decreased its clinical relevance of mimicking lung cancer progression. In contrast, mice inoculated with the 3D cancer cell spheroids better mimic the progression of non‐small cell lung cancer in the clinic.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .