{"doi":"10.1101/2025.10.22.683948","title":"N-cadherin in osteolineage cells restrains breast cancer cell growth via inhibition of a PI3K-dependent, Tgf-β1-driven feed-forward loop","abstract":"Abstract Tumor growth and metastases are affected by interactions between tumor and microenvironment cells. We have reported the presence of Sp7 -positive cells with an osteogenic signature in primary mouse breast cancer, where they stimulate tumor growth; and genetic ablation of Cdh 2 (encoding N-cadherin) in these cells enhances their pro-tumorigenic action. To study the molecular mechanisms of this biologic system, we used MC3T3 cells, phenotypically similar to tumor associated osteolineage cells. Ablation of Cdh2 in MC3T3 cells enhances PI3K-Akt-β-catenin signaling in response to transforming growth factor-β1 (Tgf-β1), resulting in increased production of Tgf-β1. Interference with PI3K activity is mediated by N-cadherin binding to PI3K components, p85α and p100, resulting in reduced activation of PI3K-Akt-β-catenin signaling. Downstream, Cdh2 ablation enhances Tgf-β1-induced binding of Sp1 and Lef-1 to the Tgfb1 promoter, leading to increased promoter activity and enhanced Tgf-β1 production. This is associated with miR-21 up-regulation and decreased expression of Pten, a PI3K inhibitor. MC3T3 cells promote growth of breast cancer cells (BCC) when co-cultured in vitro or co-injected in mouse mammary fat pad, and Cdh2 -deficiency enhances this pro-tumorigenic effect. Notably, genetic ablation of the Tgf-β1 receptor subunit, Tgfbr1, in BCC abrogates the pro-tumorigenic action of MC3T3 cells and its enhancement by Cdh2 ablation. Finally, Sp7-driven Tgfbr1 ablation in mice also reduces the growth of BCC in the mammary fat pad. Thus, autocrine Tgf-β1 production via PI3K-Akt-β-catenin signaling is a key mechanism by which osteolineage cells promote BCC growth, an action restrained by Ncad via interference with PI3K components. Highlights In tumor-associated osteolineage cells, N-cadherin reduces the growth of breast tumors; it also inhibits Tgf-β1-activated PI3K/AKT/β-catenin signaling Tgf-β1 produced by tumor microenvironment cells stimulates breast cancer cell growth and further autocrine production of Tgf-β1 The anti-tumorigenic action of N-cadherin is mediated by a braking effect on a Tgf-β1-driven, pro-tumorigenic, feed-forward cycle between microenvironment and tumor cells.","journal":"bioRxiv (Cold Spring Harbor Laboratory)","year":2025,"id":578913,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":0,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9505,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2025-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":1489172,"name":"K T Yeo","orcid":null,"position":1,"is_corresponding":false},{"id":1489173,"name":"Marco Campioli","orcid":null,"position":2,"is_corresponding":false},{"id":1489174,"name":"Hillary Fujimoto","orcid":null,"position":3,"is_corresponding":false},{"id":502905,"name":"Roberto Civitelli","orcid":"0000-0003-4076-4315","position":4,"is_corresponding":false},{"id":1275888,"name":"Toshifumi Sugatani","orcid":"0000-0001-6282-7554","position":0,"is_corresponding":true}],"reference_count":41,"raw_metadata":null,"created_at":"2026-07-19T02:58:24.957414Z","pmid":"41280061","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}