Data Sheet 1_Extracellular vesicle-mediated preconditioning of osteoblasts by ER+ breast cancer cells: implications for the bone metastatic niche.pdf

Intercellular communication between tumor cells and bone-resident cells plays a critical role in promoting tumor invasion and development of metastatic bone lesions. Historically, tumor-bone interactions have been viewed largely through the lens of soluble factor-mediated signaling, particularly in the context of osteoclast-driven bone resorption and osteolytic lesion formation.

However, the majority of bone metastases exhibit a mixed lytic and sclerotic phenotype, reflecting the combined involvement of osteoclast- and osteoblast-mediated remodeling. Here, we investigate how ER+ breast cancer-derived extracellular vesicle-enriched conditioned media influence osteoblast behavior and signaling in vitro, positioning osteoblasts as key intermediaries in bone metastatic progression. We first show that ER+ T47D cells release significantly higher EVs than MCF10A non-tumorigenic breast epithelial cells.