Fe3O4 and Fe3O4core Aushell-based Hyperthermia Reduces Expression of Proliferation Markers Ki-67, TOP2A and TPX2 in a Human Breast Cancer Cell Line.

Background/Aim: Hyperthermia represents an adjuvant local anticancer strategy which relies on the increase of temperature beyond the physiological level. In this study, we investigated the anticancer potential of Fe₃O₄ and Fe₃O_4core Au_shell nanoparticles as hyperthermic agents in terms of cytotoxicity and studied the expression of cellular markers of proliferation (changes in mRNA levels via realtime polymerase chain reaction). Materials and Methods: The human breast cancer cell line SK-BR-1 was incubated with either Fe₃O₄ or Fe₃O_4core Au_shell nanoparticles stabilized with tryptophan, prior to hyperthermia treatment. The normal HEK293 cell line was used as a control. Toxicity was determined using the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium assay to estimate possible toxic effects of the tested nanoparticles. After RNA extraction and cDNA synthesis, mRNA expression of three indicators of proliferation, namely marker of proliferation Ki-67, DNA topoisomerase II alpha (TOP2A) and TPX2 microtubule nucleation factor (TPX2), was investigated. Results: At each concentration tested, Fe₃O_4core Au_shell nanoparticles showed greater toxicity compared to Fe₃O₄, while SK-BR-3 cells were more susceptible to their cytotoxic effects compared to the HEK293 cell line. The expression of Ki-67, TOP2A and TPX2 was reduced in SK-BR-3 cells by both Fe₃O₄ or Fe₃O_4core Au_shell nanoparticles compared to untreated cells, while the only observed change in HEK293 cells was the up-regulation of TOP2A. Conclusion: Both Fe₃O_4core Au_shell and Fe₃O₄ NPs exhibit increased cytotoxicity to the cancer cell line tested (SK-BR-3) compared to HEK293 cells. The down-regulation in SK-BR-3 cells of the three proliferative markers studied, Ki-67, TOP2A and TPX2, after incubation with NPs suggests that cells that survived thermal destruction were not actively proliferating. [ABSTRACT FROM AUTHOR]