Establishment and comprehensive characterization of a subline with highly bone-metastatic propensity derived from the lung adenocarcinoma A549 cell line

Bone metastasis is a major cause of mortality in lung adenocarcinoma, but the mechanisms remain poorly understood. Here, we established a highly bone-metastatic subline, A549-BM5, from the A549 cell line through five rounds of <i>in vivo</i> selection. A549-BM5 cells exhibited enhanced migration and invasion, and preferentially colonized specific skeletal sites in mouse models. In the bone microenvironment, they promoted the recruitment and differentiation of osteoblasts and osteoclasts, disrupting bone homeostasis. Transcriptomic and proteomic profiling revealed dysregulation in pathways such as EMT, adhesion, and bone morphogenesis. We further applied a random forest model to identify potential therapeutic targets associated with bone metastasis. Compared to existing A549-based models, A549-BM5 offers earlier metastasis onset, stable bone tropism, and broader interaction with the bone niche. This model provides a valuable platform for mechanistic studies and therapeutic development targeting lung cancer bone metastasis.