Abstract 3379: Single-cell profiling reveals dynamic epithelial and immune cell interactions in the progression of lung adenocarcinoma
Authors: Chen Hong , Zhu Bo , Fujimoto Junya , Tian Yanhua , Li Jian-Rong , Li Chenyang , Chen Pingjun , Reuben Alexandre , Nilsson Monique , Le Xiuning , Poteete Alissa , Hubert Shawna M. , Gibbons Don L. , Wistuba Ignacio I. , Wu Jia , Cheng Chao , Heymach John V. , Zhang Jianjun 
Published: March 2024

Abstract
Background: Lung adenocarcinoma (LUAD) is a leading cause of cancer-related deaths. Our understanding of LUAD initiation and progression is limited, impeding early diagnosis and effective treatment. A comprehensive single-cell transcriptomic analysis, unraveling the malignant transformation from normal lung to LUAD, will provide key insights into the initiation and development of this challenging disease. However, human tissues are not amendable for such analysis.
Methods: We generated two mouse models, a genetically engineered mouse model with KrasG12D activating mutation (GEMM) and a carcinogen urethane-induced mouse tumor model (CITM) in the same 129S4 background. Single-cell transcriptome sequencing was conducted on lung tissues collected at five time points after induction for each model. The LUAD and its precursors were defined by experienced lung cancer pathologists as normal lung, hyperplasia, adenoma and adenocarcinoma. This analysis aimed to characterize the dynamic interaction between epithelial and immune cells, providing insights into the initiation and progression of LUAD.
Results: A comprehensive analysis identified a total of 12 major cell types, revealing a gradual increase in the proportion of epithelial cells during LUAD progression. EpiC 1, 2, 5 and 8 were consistently found in normal lung epithelium and various stages of abnormal epithelia, indicating their role as background components in lung tissues. In contrast, EpiC 4 emerged from hyperplasia and EpiC 0 and 3 emerged from early adenoma, while EpiC 6 and 7 were predominantly present in adenocarcinoma. Further investigation into the developmental trajectory of AT2 cells indicated a clear separation between normal (EpiC 1, 2, 5 and 8) and tumor cells (EpiC 0, 3, 4, 6 and 7). Cancer hallmark analysis revealed that tumor clusters exhibited higher scores in KRAS_SIGNALING_UP, HYPOXIA, APOPTOSIS, and P53_PATHWAY compared to normal epithelial clusters, suggesting the potential activation of these pathways in the tumorigenesis. Furthermore, the proportion of Macro_C1qc increased over time, accompanied by Macro_C1qc exhibiting the highest M2 signature score. This indicates a unique enrichment of M2-like macrophages in LUAD tissues. Remarkably, a notable increase in ligand-receptor pairs contributed significantly to the signaling from macrophages to tumor cells during progression. The dynamic regulatory interplay between Macro_C1qc and tumor cells was notably mediated by Thbs-Sdc1, App-Cd74, Spp1-Cd44 and other L-R pairs across various time points.
Conclusion: We constructed a single-cell LUAD developmental atlas of dynamic tumor-immune cell interactions, which sheds light on the initiation and progression of LUAD. Notably, our findings underscore a potential crucial role of macrophages, particularly M2 in lung tumorigenesis.
Citation Format: Hong Chen, Bo Zhu, Junya Fujimoto, Yanhua Tian, Jian-Rong Li, Chenyang Li, Pingjun Chen, Alexandre Reuben, Monique Nilsson, Xiuning Le, Alissa Poteete, Shawna M. Hubert, Don L. Gibbons, Ignacio I. Wistuba, Jia Wu, Chao Cheng, John V. Heymach, Jianjun Zhang. Single-cell profiling reveals dynamic epithelial and immune cell interactions in the progression of lung adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3379.