J Neurol Surg B Skull Base 2016; 77 - A043
DOI: 10.1055/s-0036-1579832

Feasibility of Non-Thermal Atmospheric Pressure Plasma as Adjuvant Treatment Modality for Vestibular Schwannoma

Yeo Jun Yoon 1, Kiwon Song 1, Eun Ha Choi 2
  • 1Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea
  • 2Department of Electrophysics, Kwangwoon University, Seoul, South Korea

Objective: Vestibular schwannoma is usually a benign tumor. However, its location is close to brain stem and nerve complex which could cause mortality and morbidity. Complete resection of tumor can sometimes cause permanent complications such as facial palsy or hearing loss, but subtotal resection can cause recurrence. Minimizing remnant tumor after subtotal or near total removal may have a positive impact on the patient’s wellbeing. Here, NTAPP is known to induce apoptosis in tumor cells through production of ROS and also preserve adjacent functional organs. If NTAPP has an effect on vestibular schwannoma, it can be utilized as adjuvant modality to eliminate remnant tumor in surgical field. It is different from the concept of gamma knife surgery which can injure normal hearing and balance organs. Prior to in vivo study, we investigated the apoptotic effect of NTAPP in in vitro using a vestibular schwannoma cells (NF2 −/− schwann cell).

Method: We used a NF2 −/− schwann cell (SC4) with optimal exposure to NTAPP. Cells were incubated at least 16 hour before NTAPP treatment. Then the cells were further incubated for up to 72hrs after NTAPP treatment. MTT assay was used to measure the viability of the cells. Next, protein expression was observed through western blot. Finally, Annexin V and 7-AAD double staining with FACS analysis was used for the determination of apoptosis and/or necrosis. We also analyzed the impact of NTAPP to normal tissue using fibroblast and adipose stem cells to confirm selective apoptosis of SC4 cells.

Result: SC4 cells treated with NTAPP for 5 minute; western blot analysis showed that pro-apoptotic protein PARP and Caspase-3 were activated in these cells, as well as an increase in p-p53 activation. FACS analysis revealed apoptosis as the major cause of cell death rather than necrosis.

Conclusion: The results of this experiment suggest that NTAPP treatment can be effectively used to minimize remnant tumor without damage to adjacent normal functional organ.