NGF-mediated tumor–stroma crosstalk promotes prostate cancer aggressiveness

Abstract Background Nerve growth factor (NGF) is involved in prostate cancer (PC) pathogenesis and progression. Nevertheless, its source and its role in tumor microenvironment remain still unclear as well as its contribution to tumor–stroma interactions. Methods Single-cell transcriptomics analysis from multiple PC datasets was performed to identify the NGFexpressing cell populations. Primary cancer-associated fibroblasts (CAFs) isolated from PC patient’s specimens were analyzed for NGF secretion and expression of the NGF receptor, TrkA. 3D tumor-stroma co-cultures were used to investigate the NGF-mediated interactions between CAFs and epithelial PC cells. Migration, invasion, and perineural invasion (PNI) assays were done to evaluate the functional outcomes, alongside the pharmacological and antibodybased inhibition of NGF/TrkA axis. Results High NGF expression correlates with reduced disease-free survival in PC patients. Single-cell analyses reveal that stromal fibroblasts and myofibroblasts are the main sources of NGF within the PC microenvironment. Primary CAFs secrete NGF and express TrkA, supporting the existence of an autocrine signaling loop. In 3D co-cultures, NGF promotes CAF spatial organization around tumor spheroids, increases spheroid size, and induces EMT-like changes in epithelial PC cells. CAF-derived NGF further stimulates directional migration and invasion in both, CAFs and tumor cells. Blockade of NGF by neutralizing antibodies or pharmacological TrkA inhibition impairs such effects. In a PNIlike assay, CAF-derived NGF facilitates tumor cell migration across neuronal layers, underscoring its role in perineural invasion. Conclusions The present findings identify fibroblasts as the major source of NGF within the PC microenvironment, demonstrating the existence of a reciprocal NGF–TrkA signaling loop between CAFs and PC-derived cells. This axis promotes tumor growth, epithelial plasticity, and perineural invasion, identifying NGF as a key mediator of tumor– stroma crosstalk and a potential therapeutic target in prostate cancer. Keywords Nerve growth factor, Tumor microenvironment, Prostate cancer