Characterization of the properties of HEI-OC1 cells

Abstract

The HEI-OC1 (House Ear Institute-Organ of Corti 1) auditory cells display properties of hair-cell progenitors including sensitivity to cisplatin and aminoglycoside antibiotics. HEI-OC1 cells are an excellent in vitro system to investigate the cellular and molecular mechanisms involved in ototoxicity and for screening of the potential ototoxicity or otoprotective properties of new pharmacological drugs1, 2. However, some authors have reported discrepancies in their results on the response of these cells to some specific treatment and they have mentioned that the results using HEI-OC1 cells may vary depending on culture conditions3. Due to this, is important to establish the culture conditions and to characterize the properties of HEI-OC1 cells before to test the ototoxicity or otoprotective properties of any new drug. We have evaluated in the HEIOC1 cells, the cell cycle, the percentage of apoptosis and the expression of different molecular markers of organ of Corti in permissive (proliferative; 33 °C and 10% CO2) and non-permissive conditions (differentiated; 39 °C and 5% CO2) by flow cytometry and immunocytochemistry assays. The cell toxicity in response to cisplatin at five different doses after 24 h was assessed by crystal violet technique. The HEI-OC1 cells, when were cultured under non-permissive conditions, presented a higher percentage of apoptotic, a higher number of quiescent cells (G0/G1), and a fewer number of cells in the phases S and G2/M than when they were cultured under permissive conditions. In permissive conditions, the HEI-OC1 cells expressed MyosinVIIa, MATH1, SOX2 and p-histone H3; whereas non-permissive conditions caused the cells to differentiate and the down-regulation of MATH1, SOX2 and p-histone H3 levels. The treatment of HEIOC1 cells with cisplatin results in a significant and dose-dependent decrease in cell viability, as already described in previous studies