Abstract 3387: Spatial analysis revealed distinct molecular and immune landscape in genetic versus carcinogen-induced lung adenocarcinoma precancer mouse models
Authors: Zhu Bo , Chen Pingjun , Li Jian-Rong , Aminu Muhammad , Li Chenyang , Chen Hong , Tian Yanhua , Rojas Frank R. , Roger Parra Cuentas Edwin , Shi Ou , Nilsson Monique B. , Poteete Alissa , Hubert Shawna M. , Khan Khaja B. , Lu Wei , Song Xingzhi , Zhang Jianhua , Gibbons Don L. , Soto Luisa M. Solis , Wistuba Ignacio I. , Heymach John V. , Cheng Chao , Wu Jia , Zhang Jianjun 
Published: March 2024

Introduction: Our understanding of early carcinogenesis of lung adenocarcinoma (LUAD) is still rudimentary. Single-cell technologies have unveiled the intricate interaction between tumor cells and tumor microenvironment (TME) with unprecedented precision. However, the spatial context of single-cell phenotypes within TME during LUAD early carcinogenesis remain poorly understood. Here, we sought to characterize human-relevant murine LUAD precancer models to elucidate the molecular and immune changes in the spatial context during early LUAD carcinogenesis to inform lung cancer interception strategies.

Methods: We have developed genetically engineered mouse models (GEMMs) (129S4 KrasG12D) and carcinogen-induced LUAD precancer model (CITM) (129S4 Urethane). Lung tissues were collected at various time points after induction and analyzed using whole exome sequencing (WES), imaging mass cytometry (IMC), and spatial transcriptomics (10x Visium).

Results: Pathological image analysis demonstrated a significantly higher tumor burden (p&lt;0.01) in the 129S4 KrasG12D model compared to the 129S4 Urethane model across different time points. WES revealed a progressive increase in tumor mutation burden (TMB) from precancers to invasive LUADs in both models, with the CITM model having significantly higher TMB (p&lt;0.05) at matched timepoints than GEMM model. IMC assessed 39 biomarkers in 284 regions of interest (ROIs) and identified 1.4 million individual cells with 17 major cell types. Macrophages were the most prevalent immune cell type in TME, representing 9.00% of total cells in GEMM and 8.29% in CITM. The percent immune cells of the total cells progressively decreased from early-stage hyperplasia to late-stage adenocarcinoma in both models. The CITM exhibited a significantly (p&lt;0.05) higher immune proportion than the GEMM model at hyperplasia and adenoma stages, with no significant difference at the invasive adenocarcinoma tumor cores between these 2 models. On the other hand, CITM had a significantly higher overall immune proportion (p&lt;0.05) and the CD8 T cell and B cell proportions than GEMM tumor adjacent lung tissues at the adenocarcinoma stage leading to a significantly higher immune cell gradient between tumor adjacent lung tissues and tumor cores in CITM models. Spatial transcriptomics (ST) data demonstrated an increased presence of immune response signaling at the tumor adjacent lung tissues compared to the tumor core in the latest stage.

Conclusion: Spatial analysis revealed different molecular and immune landscapes in the genetic and carcinogen-induced LUAD precancer models, leading to distinct cellular spatial arrangements within the tumor microenvironment in each model. Overall, innate immunity, particularly macrophage, probably plays critical roles during early carcinogenesis of LUAD regardless of carcinogen exposure.

Citation Format: Bo Zhu, Pingjun Chen, Jian-Rong Li, Muhammad Aminu, Chenyang Li, Hong Chen, Yanhua Tian, Frank R. Rojas, Parra Cuentas Edwin Roger, Ou Shi, Monique B. Nilsson, Alissa Poteete, Shawna M. Hubert, Khaja B. Khan, Wei Lu, Xingzhi Song, Jianhua Zhang, Don L. Gibbons, Luisa M. Solis Soto, Ignacio I. Wistuba, John V. Heymach, Chao Cheng, Jia Wu, Jianjun Zhang. Spatial analysis revealed distinct molecular and immune landscape in genetic versus carcinogen-induced lung adenocarcinoma precancer mouse models [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 3387.