Abstract 5845: Periostin secreted by cancer-associated fibroblasts promotes cancer progression and drug resistance in non-small cell lung cancer

Abstract

Abstract Background: Cancer-associated fibroblasts (CAFs) are key players in the tumor microenvironment (TME) due to their abundance in most solid tumors and active crosstalk with cancer cells, and promote the initiation of tumor formation, tumor growth, angiogenesis, metastasis, and therapeutic resistance. In this study, we sought to identify effective therapeutic targets in CAFs for non-small cell lung cancer (NSCLC). Experimental Design: We established fibroblast cell lines from the cancerous and non-cancerous parts of surgical lung specimens from patients with NSCLC and evaluated the differences in behaviors towards NSCLC cells using in vitro co-culture models, conditioned medium, and in vivo xenograft mouse models. Next, RNA sequencing analysis was performed to investigate the differentially expressed genes between normal fibroblasts (NFs) and CAFs, and we then verified the biological activity of the identified molecule on NSCLC cells in vitro and in vivo mouse model. Results: Cancer cells showed enhanced cell proliferation, migration, and drug resistance by co-culture with CAFs or CAF-derived conditioned medium. RNA sequencing analysis revealed that CAFs showed higher expressions of POSTN, a matricellular protein, than NFs. Single-cell RNA sequencing data of NSCLC from public database confirmed that POSTN-positive fibroblasts were highly enriched in lung tumor tissues but rarely observed in normal lung tissues, suggesting CAF-specific POSTN expression in lung cancer. Recombinant POSTN increased cell proliferation via NSCLC cells’ ERK pathway activation and induced epithelial-mesenchymal transition (EMT), which improved migration in vitro. In addition, POSTN knockdown in CAFs suppressed these effects, and in vivo experiments demonstrated that the POSTN knockdown improved the sensitivity of EGFR-mutant NSCLC cells for Osimertinib treatment. Conclusion: Our results showed that CAF-derived POSTN is involved in tumor growth, migration, EMT induction, and drug resistance in NSCLC. Targeting CAF-secreted POSTN in TME could be a potential therapeutic strategy for NSCLC. Citation Format: Mao Yoshikawa, Fumiaki Takatsu, Ken Suzawa, Tomohiro Habu, Ohki Masayoshi, Kazuma Iwata, Naoki Matsuda, Yin Min Thu, Kazuhiko Shien, Hiromasa Yamamoto, Shinichi Toyooka. Periostin secreted by cancer-associated fibroblasts promotes cancer progression and drug resistance in non-small cell lung cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5845.