Hyperthermia-driven aberrations of secreted microRNAs in breast cancer in vitro

AbstractPurpose: Expression profile alterations of nine breast cancer (BC)-associated secreted microRNAs (miRs) were determined under microenvironmental alterations occurring in tumour progression, metastasis or specific oncological treatment modalities. Thereto, the potential influence of the exogenic stimuli hypoxia, acidosis and hyperthermia was investigated in vitro.Material and methods: Four established BC cell lines were applied as in vitro BC model systems. Quantitative analyses of secreted microRNA specimens were performed by RNA isolation from cell culture supernatant and subsequent real-time PCR in cells under physiological versus hypoxic, acidic or hyperthermia conditions.Results: The in vitro application of exogenic stimuli hypoxia, extracellular acidosis and hyperthermia caused heterogeneous expression alterations for the investigated secreted miRNA phenotypes. The majority of relevant exogenic stimuli-dependent microRNA expression alterations were restricted to single events displaying disti...