In cooperation with the Institute of Pharmacology and Toxicology, Paracelsus Medical University: Cellular models of cisplatin-induced ototoxicity

Abstract

Cisplatin is a drug commonly used to treat various types of cancer. It is a highly effective agent, but it is also associated with severe side effects. In addition to DNA damage, the platinum-based drug increases reactive oxygen species (ROS) production, which can lead to apoptosis of hair cells in the cochlea and eventually to irreversible hearing loss. The objective of this study is to establish in vitro models for the investigation of cisplatininduced oxidative stress on molecular targets that are important for hearing. For this aim, HEK293 Phoenix and SK-MEL-24 cells were utilized. These cells express endogenously K + channels that are abundantly expressed in the ascending auditory pathway and the stria vascularis and play a fundamental role in hearing. HEK293 Phoenix and SK-MEL-24 cells were treated with 5 µM, 10 µM, 20 µM, and 50 µM cisplatin for 6 h and 16 h. To analyse the influence of cisplatin on the generation of oxidative stress in these cell lines, total ROS production was measured. In parallel, cell viability was analysed in order to evaluate the toxicity of the treatment. The expression levels of different biomarkers, including CAT, SOD1, SOD2, NOX3, NFE2L2 (Nrf2), and the expression of the Kv3.1/KCNC1 K + channel were investigated by RT-qPCR following treatment with cisplatin. As a marker of ER-stress, the protein calreticulin were analysed by Western Blot. The expression of p-Src, total-Src, and the protein levels of Kv3.1 were also investigated. The results showed a significant influence of cisplatin on the production of ROS, which was probably the consequence of an upregulation of the expression of NOX3 in HEK293 Phoenix cells. Decreased transcript levels of KCNC1 might contribute to cisplatininduced hearing loss. Interestingly, cisplatin had no significant impact on the protein calreticulin in HEK293 Phoenix and SK-MEL-24 cells, indicating that no ER-stress is involved in this setting, but led to a decrease in expression of p-Src and total-Src in HEK293 Phoenix cells with 50 µM cisplatin treatment. These results represent an essential prerequisite for future investigations on the possible use of antioxidants in counteracting cisplatin-induced hearing loss.

Date of Award	2025
Original language	English
Supervisor	Manuel Selg (Supervisor)