Antagonistic SMAD2/3 control of TIMP-1, VEGF-A, and hypoxia signaling in myofibroblasts shapes histotype-specific angiogenesis in lung cancer.

Non-small cell lung cancer (NSCLC) exhibits disparate responses to anti-angiogenic therapies between its two major histologic subtypes, lung adenocarcinoma (LUAD) and squamous cell carcinoma (LUSC), suggesting a histotype-dependent angiogenesis regulation. Tumor-associated fibroblasts (TAFs) exhibit an activated/myofibroblast-like phenotype in NSCLC, and are emerging as major regulators of tumor progression; yet, their role in controlling angiogenesis in NSCLC remains undefined. Here we analyzed angiogenesis/hypoxia markers in NSCLC, and combined transcriptomics (bulk RNA-seq, scRNA-seq), angiogenesis arrays, genetic perturbations and functional in vitro and in vivo assays to dissect the histotype-dependent production of pro-angiogenic factors in TAFs. We observed greater angiogenesis and reduced necrosis/hypoxia in LUAD compared to LUSC across multiple patient cohorts. The LUAD-TAF secretome was primed for angiogenesis through SMAD3-dependent overproduction of key regulators, particularly TIMP-1 and VEGF-A. We also uncovered a novel function for TIMP-1 in promoting endothelial cell hyperbranching over basal VEGF signaling. Conversely, LUSC-TAFs displayed diminished angiogenic effects despite upregulating HIF-1α and a hypoxia-associated transcriptional signature, owing to their lower SMAD3 and compensatory increase in SMAD2. Our study unveils the critical influence of TAFs in shaping the distinct angiogenic landscapes in LUAD and LUSC through the opposing SMAD2/3 regulation of TIMP-1, VEGF-A and hypoxia signaling. These results also highlight the therapeutic potential of targeting stromal SMAD3/TIMP-1 in LUAD or microenvironmental stressors such as hypoxia and acidosis in LUSC. In addition, these findings provide a biological framework for understanding the histotype-dependent patterns of dissemination, immune evasion, and response to anti-angiogenic therapies in NSCLC.