Aneuploidy of a murine immortalized endothelial cell line, MS1

Objectives We have previously reported that tumor endothelial cells (TECs) are chromosomally abnormal. It is generally known that immortalized cells have chromosomal abnormalities. In this study, our objective was to compare chromosomal properties of an immortalized normal endothelial cell (NEC) line, MS1, and those of TECs, to assess the possible usefulness of MS1 cells as a surrogate for TECs, which have some experimental intractability as primary cultured endothelial cells. Methods Primary cultured NECs were isolated from murine dermis tissue. Fluorescence in situ hybridization was performed to analyze aneuploidy in MS1 cells and NECs. DNA damage response (DDR) activation was analyzed by γH2AX staining. We also tested the involvement of reactive oxygen species (ROS) in the chromosomal abnormalities of MS1 cells. Results MS1 cells showed a higher rate of aneuploidy than NECs did (91.6% versus 7.6%). A DDR was activated to a greater extent in MS1 cells than in NECs, judging by H2AX phosphorylation. ROS induced H2AX activation in MS1 cells, suggesting that ROS are involved in their DDR. Conclusion MS1 cells are aneuploid and activate H2AX to a greater extent than NECs do. MS1 cells resemble TECs in terms of the proliferative phenotype and aneuploidy. Thus, MS1 may be a good cell line for studies on the relation between chromosomal instability and a DDR in nonmalignant cells.