Development of gene signatures for doxorubicin resistance and cancer stem cell CD44+, CD24-/low ALD+ isolated from canine mammary adenocarcinoma cell line (microRNA)

CMT-Stylo is a canine mammary gland adenocarcinoma cell line. From this cell line, a doxorubicin resistant subline called CMT-Star was developed by culturing the cells in the presence of doxorubicin from low concentration to 100 nM doxorubicin (to induce drug resistance). The CMT-Stylo cells were maintained in Dulbecco’s modified eagles medium (DMEM) supplemented with 10% Foetal bovine serum (FBS) and 1% Penicillin-Streptomycin (ThermoFisher Scientific, USA) in 5% CO2 at 370C. The CMT-Star cell line was maintained in additional 5 nM doxorubicin to maintain its resistant phenotype. We set out to identify differentially expressed messenger RNAs between the CMT-Stylo cells and CMT-Star cells using canine specific cDNA microarrays. Additionally, we isolated cancer stem cells from the cell line and its doxorubicin resistant subline using flow cytometry ( CD44+, CD24-/low and ALDH+ cells sorted using FACS sorter) and using microarray, we identified differentially expressed messenger RNAs between each cell line and its cancer stem cells. At a fold change of 2 and p-value of p < 0.05, a total of 26652 messenger RNA entities were identified as dysregulated between CMT-Stylo cells and CMT-Star cells. Similarly, we identified 28614 messenger RNA entities as differentially expressed between CMT-Stylo cells and their cancer stem cells, and 1808 messenger RNAs entities between CMT-Star cells and their cancer stem cells, using the same parameters.