Comparison of Characterization in Two-Dimensional and Three-Dimensional Canine Mammary Gland Tumor Cell Models

Abstract

Background Canine mammary gland tumors can be used as predictive models for human breast cancer. There are several types of microRNAs common in human breast cancer and canine mammary gland tumors. The functions of microRNAs in canine mammary gland tumors are not well understood. Methods We compared the characterization of microRNA expression in two-dimensional and threedimensional canine mammary gland tumor cell models. We evaluated the differences between two-and threedimensional cultured canine mammary gland tumor SNP cells by assessing microRNA expression levels, morphology, drug sensitivity, and hypoxia. Results The expression of microRNA-210 in the three-dimensional-SNP cells was 10.19 times higher than that in the two-dimensional-SNP cells. The intracellular concentrations of doxorubicin in the twoand three-dimensional-SNP cells were 0.330 ± 0.013 and 0.290 ± 0.048 nM/mg protein, respectively. The IC50 values of doxorubicin for the two-and threedimensional-SNP cells were 5.2 and 1.6 μM, respectively. Fluorescence of the hypoxia probe, LOX-1, was observed inside the sphere of three-dimensional-SNP cells without echinomycin but not in two-dimensionalSNP cells. The three-dimensional-SNP cells treated with echinomycin showed weak LOX-1 fluorescence. Conclusion The present study showed a clear difference in microRNA expression levels in cells cultured in a two-dimensional adherent versus a three-dimensional spheroid model.