Abstract LB446: Decoding the mechanism of metastasis: A novel CAF-therapy that blocks the tumor microenvironment and reverses metastatic traits in all solid tumors

Abstract Progression and metastatic spreading of cancer cells are modulated by the carcinoma-associated fibroblasts (CAFs) within the primary tumor microenvironment in solid tumors. However, the mechanisms through which CAFs exert their pro-metastatic effects on cancer cells remain unknown. In this study, we have developed a small molecule that blocks Neuropilin-1 signaling in metastatic CAFs (mCAFs), reversing the mechanisms that promote metastasis in prostate, breast, colorectal and pancreatic cancer. To address these critical needs, in this study, we sought to assess the potential role of proteoglican neuropilin 1 (PG-NRP1) signaling in the maintenance of the activated CAF phenotype. Our results by gene expression profile, qPCR, WB, and ELISA indicate that CAFs isolated from primary tumors of metastatic patients (mCAFs) are functionally different from CAFs isolated from primary tumors of non-metastatic patients, promoting metastasis traits of cancer cells. Among the most prominent differences is an increased PG-NRP1 expression. siRNA studies demonstrated that the knockdown of NRP-1 in mCAFs showed the reversion of the activated phenotype, evaluated by the activation markers a-SMA, Tenascin C, and Fibronectin. Furthermore, conditioned media from PG-NRP1-siRNA-mCAFs failed to increase cancer cells' metastasis traits (migration and invasion) in vitro and tumor progression in vivo. Furthermore, we engineered a small molecule designed to bind PG-NRP1 in mCAFs. Our findings, demonstrate in vitro and in vivo models that the inhibition of PG-NRP1 impedes tumor growth and metastatic dissemination of cancer cells in spontaneous metastasis assay. We designed and validated, using in vivo models, an inhibitor that blocks NRP1-mCAF. Our research demonstrates that blocking PG-NRP1 in mCAF, with a small molecule, is a transversal therapeutic strategy to prevent progression and metastatic spread in solid cancer tumors. Citation Format: Benjamin Prieto, Muriel Núñez, Valentina I. Cerdfa, Javier Cerda-Infante. Decoding the mechanism of metastasis: A novel CAF-therapy that blocks the tumor microenvironment and reverses metastatic traits in all solid tumors abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts) ; 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84 (7Suppl): Abstract nr LB446.