MDA-MB-231-GFP

MDA-MB-231-GFP is a fluorescently labeled variant of the widely used MDA-MB-231 human breast cancer cell line, engineered to express green fluorescent protein (GFP) via lentiviral transduction. This modification enables real-time visualization and quantification of tumor cell dynamics both in vitro and in vivo, facilitating detailed analysis of tumor-stroma interactions, cellular proliferation, and metastatic behavior. The parental MDA-MB-231 line originates from a pleural effusion of a patient with triple-negative breast cancer (TNBC) and exhibits aggressive, invasive behavior with a mesenchymal phenotype, making it a cornerstone model for studying TNBC pathophysiology and treatment resistance. In co-culture experiments with human mesenchymal stem/stromal cells (MSCs), MDA-MB-231-GFP cells have demonstrated significantly enhanced proliferation and tumor-promoting behavior. Studies showed that direct contact with MSCs, rather than soluble factors alone, is critical for this effect. Specifically, co-culture with MSCs led to a 39.5% increase in MDA-MB-231-GFP cell proliferation after four days compared to monoculture, and induced expression of CD90 on a subset of breast cancer cells—a marker not expressed under standard conditions. This MSC-induced CD90 expression required direct cell–cell interaction and was partially inhibited by blocking gap junctions or Notch signaling, indicating the involvement of specific intercellular communication pathways. In vivo, co-injection of MDA-MB-231-GFP cells with MSCs into immunodeficient NOD/scid mice resulted in approximately tenfold increased tumor volume and enhanced metastatic potential compared to injection of cancer cells alone. These tumors exhibited elevated vascularization and higher viability, and retained a minority CD90-positive population, reinforcing the in vitro findings. Together, these studies position MDA-MB-231-GFP as a robust model for investigating tumor-stroma interactions, MSC-induced phenotypic plasticity, and mechanisms of tumor progression in triple-negative breast cancer.