Abstract 5484: Spatial transcriptomic profiling reveals characteristic gene expression patterns of cancer-associated fibroblasts in lung adenocarcinoma with interstitial pneumonia
Authors: Inoue Chihiro , Miki Yasuhiro , Aoyama Yayoi , Shibata Saori , Okada Yoshinori , Suzuki Takashi 
Published: March 2024

Background: Interstitial pneumonia (IP) is a risk factor for lung cancer (LC). LC, a significant contributor to mortality, shows improved prognosis with molecular targeted drugs. However, LC combined with IP (LC with IP) has a poor prognosis because of acute exacerbations. Therefore, developing effective drugs for LC with IP is necessary. Cancer-associated fibroblasts (CAFs), influencing cancer progression through interactions with the microenvironment are anticipated as a new therapeutic target. Therefore, we hypothesized that CAFs in LC with IP, having undergone repeated destruction and regeneration, exhibit distinct characteristics from those in LC without IP and exert varied influences on carcinogenesis and cancer progression.

Methods: Six cases of lung adenocarcinoma, the predominant type of LC, were enrolled in this study. Spatial profiling was performed on FFPE specimens from three LC with IP and three LC without IP cases, using GeoMx whole-transcriptome atlas assay. Immunostaining for α-SMA, a major CAFs-marker, and pan-cytokeratin (CK), an epithelial marker, were employed to identify regions of interest (ROIs). In LC with IP, two ROIs were designated for cancerous and non-cancerous areas, respectively, whereas in LC without IP, two ROIs were selected for cancerous areas. Each ROI was segmented for epithelium and cancer (CK+/α-SMA -) and α-SMA-positive stroma (CK-/α-SMA +) areas of illumination. NGS data were analyzed using the edgeR to compare mRNA expressions in cancerous (LC-IP) and non-cancerous (NC) areas of LC with IP. Additionally, comparisons were made between LC-IP and cancerous areas of LC without IP (LC-nonIP) for mRNA expression.

Results: Analysis of α-SMA-positive stroma revealed 86 differentially expressed genes (DEGs) in LC-IP vs. NC. Notably, COTL1 and NFKB2 increased, whereas TNC and MMP7 were decreased in LC-IP α-SMA-positive stroma. Pathway Enrichment analysis indicated activation of the response to cytokines. Between LC-IP and LC-nonIP, 151 DEGs were detected. CXCL8 and NFKB2 were elevated, whereas ACAN and ELN decreased in LC-IP α-SMA-positive stroma. KEGG pathway analysis demonstrated inactivated ECM-receptor interactions. Analysis of CK-positive regions showed 710 DEGs in LC-IP vs. NC, and KEGG pathway analysis indicated inactivated ECM-receptor interaction. In LC-IP vs. LC-nonIP, 321 DEGs were detected, with KEGG pathway analysis suggesting inactivation of ECM-receptor interaction and activation of a chemokine signaling pathway and cytokine-cytokine receptor interaction.

Conclusion: These findings suggest that inflammatory factors may play a more critical role than extracellular matrix in the interaction between α-SMA-positive stroma and CK-positive cancer cells in LC with IP. Future plans include conducting in vitro experiments, as well as immunohistological studies.

Citation Format: Chihiro Inoue, Yasuhiro Miki, Yayoi Aoyama, Saori Shibata, Yoshinori Okada, Takashi Suzuki. Spatial transcriptomic profiling reveals characteristic gene expression patterns of cancer-associated fibroblasts in lung adenocarcinoma with interstitial pneumonia [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 5484.