Polyethylenimine as a gene delivery tool in triple-negative breast cancer cell line and breast cancer stem cell model

Background and purpose: PEI is a cationic polymer able to neutralise negative DNA charges and to condense large genes which makes it suitable for gene delivery in human cells. Despite its low cost, simplicity of use and moderate toxicity, there is still room for broader usage and experimental adjustments, especially in cell lines that are difficult to transfect. In the presented research, we used PEI for the delivery of plasmid DNA into TNBC cell line SUM159 and breast CSC model HMLE-Twist.Material and methods: Cultured cells were transfected with GFP-expressing plasmid using both PEI and Lipofectamin. Transfection efficiency was determined by flow cytometry measurements of the intensity of the green fluorescence, while viability was determined by measuring intensity of the red fluorescence after propidium iodide staining. Results: In SUM159 and HMLE-Twist cells we obtain transfection efficiency between 30-40% using PEI, while cytotoxicity was generally low to moderate. PEI caused 10% of cell death in SUM159 and 20 % in HMLE-Twist. Transfection efficiency of PEI was comparable and even higher than the efficiency of the Lipofectamine in both SUM159 and HMLE-Twist. In mammary epithelia (control HMLE) we obtained only 20 % transfection efficiency using both carriers.Conclusions: We demonstrated for the first time that PEI represents a suitable nanocarrier for gene delivery into breast CSC model. We successfully transfected both breast CSC model HMLE-Twist and TNBC line SUM159. Since PEI is inexpensive and easy to use, we recommend it for further exploitations of these cell lines in TNBC research.