Cold Plasma Discharge Tube Enhances Antitumoral Efficacy of Temozolomide

Glioblastoma (GBM) is a fatal human brain tumor with a low survival rate. Temozolomide (TMZ) has been widely used in GBM therapy with noticeable side effects. Cold plasma is an ionized gas that is generated near room temperature. Here, we demonstrated the enhancement therapeutic efficacy of TMZ via using a cold plasma source based on nonequilibrium plasma in a sealed glass tube, named a radial cold plasma discharge tube (PDT). The PDT affected glioblastoma cells' function just by its electromagnetic (EM) emission rather than any chemical factors in the plasma. The PDT selectively increased the cytotoxicity of TMZ on two typical glioblastoma cell lines, U87MG and A172, compared with normal astrocyte cell line hTERT/E6/E7 to some extent. Furthermore, on the basis of a patient-derived xenograft model, our preliminary in vivo studies demonstrated the drastically improved mean survival days of the tumor-barrier mice by more than 100% compared to control. The PDT is not only independent of continuous helium supply but is also capable of resisting the interference of environmental changes. Thus, the PDT was a stable and low-cost cold atmospheric plasma source. In short, this study is the first to demonstrate the promising application of PDTs in GBM therapy as a noninvasive and portable modality.