Air plasma-activated medium exerts tumor-specific cytotoxicity via the oxidative stress-induced perinuclear mitochondrial clustering

Intractable cancers such as osteosarcoma (OS) and oral cancer (OC) are highly refractory, recurrent, and metastatic once developed, and their prognosis is still disappointing. Tumor-targeted therapy eliminating cancers effectively and safely is the current clinical choice. Since aggressive tumors have inherent or acquired resistance to multidisciplinary therapies targeting apoptosis, tumor-specific induction of another cell death modality is a promising avenue to meet the goal. Here, we report that a cold atmospheric air plasma-activated medium (APAM) can induce cell death in OS and OC via a unique mitochondrial clustering. This event was named monopolar perinuclear mitochondrial clustering (MPMC) because of the characteristic unipolar mitochondrial perinuclear aggregation. APAM had potent antitumor activity both i n vitro and in vivo . APAM caused apoptosis, necrotic cell death, and autophagy. APAM contained hydrogen peroxide and increased mitochondrial ROS (mROS), while the antioxidant N -acetylcysteine (NAC) prevented cell death. MPMC occurred following mitochondrial fragmentation coinciding with nuclear damages. MPMC was accompanied by the tubulin network remodeling and mitochondrial lipid peroxide (mLPO) accumulation and prevented by NAC and the microtubule inhibitor, Nocodazole. Increased Cardiolipin (CL) oxidation was also seen, and NAC and the peroxy radical scavenger Ferrostatin-1 prevented it. In contrast, in fibroblasts, APAM induced minimal cell death, mROS generation, mLPO accumulation, CL oxidation, and MPMC. These results suggest that MPMC is a tumor-specific cause of cell death via mitochondrial oxidative stress and microtubule-driven mitochondrial motility. MPMC might serve as a promising target for exerting tumor-specific cytotoxicity. ![Figure][1] Graphical abstract ### Competing Interest Statement Manami Suzuki-Karasaki, Miki Suzuki-Karasaki, and Dr. Yoshihiro Suzuki-Karasaki are employees of the Non-Profit Research Institute Plasma ChemiBio Laboratory. Other authors have no conflicts of interest. The funders had no role in the study's design, in the collection, analyses, or interpretation of data, in the writing of the manuscript, or in the decision to publish the results. [1]: pending:yes