Effective pressure and treatment duration of high hydrostatic pressure to prepare melanoma vaccines

Current therapeutic methods for melanoma have numerous limitations, and thus the improvement of such treatment methods are essential. One possible option is the vaccination of autologous inactivated tumor cells. The primary indispensable principles of a cell-based melanoma vaccine include: i) Entire inactivation of melanoma cells; ii) retaining the immunogenicity of melanoma cells; and iii) adherence to laws and ethical guidelines. However, traditional methods for the production of the vaccine, such as ultrasonic, chemotherapeutics and freeze-thawing, have some juridical or therapeutic constraints. Therefore, the present study used high hydrostatic pressure (HHP) to inactivate malignant cells, and treated B16-F10 tumor cells with different pressures (≥50 MPa) and different durations (≥1 min). It was identified that tumor cells in vitro lost their proliferative ability, but retained their immunogenicity following treatment. Furthermore, the vaccination of the melanoma cells significantly suppressed their oncogenesis. Collectively, the present results suggest that HHP treatment may be an economically viable and effective measure to develop a melanoma vaccine, when pressure was ≥200 MPa and the treatment duration was ≥30 min.