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Atypical teratoid/rhabdoid tumor (AT/RT) is the most malignant tumor of the central nervous system that generally occurs in young children. Despite the use of intensive multimodal therapy for AT/RT, the prognosis is still poor. The brain tumor initiating cells in AT/RT cells has been suggested as one of the challenges in AT/RT treatment. These cells have high expression of aldehyde dehydrogenase (ALDH). We investigated the combination effect of the ALDH inhibitor, disulfiram and cisplatin in the treatment of AT/RT cells. Isobologram analysis revealed that the combination therapy synergistically increases AT/RT cell death. The enzyme activity of ALDH AT/RT cells was effectively reduced by the combination therapy. We proposed that the synergistic augmentation occurs, at least partially through an increase in cleaved Poly (ADP-ribose) polymerase (PARP)-dependent apoptosis mediated by activating transcription factor 3 (ATF3). In the AT/RT mouse model, the combination therapy decreased tumor volume and prolonged survival. Immunofluorescence assay in mouse brain tissues were consistent with the expression of ATF3 and cleaved PARP. Our study demonstrates enhanced anti-cancer effect of combination therapy of disulfiram and cisplatin. This combination might provide a viable therapeutic strategy for AT/RT patients.

Nonthermal plasma is a promising novel therapy for the alteration of biological and clinical functions of cells and tissues, including apoptosis and inhibition of tumor progression. This therapy generates reactive oxygen and nitrogen species (RONS), which play a major role in anticancer effects. Previous research has verified that plasma jets can selectively induce apoptosis in various cancer cells, suggesting that it could be a potentially effective novel therapy in combination with or as an alternative to conventional therapeutic methods. In this study, we determined the effects of nonthermal air soft plasma jets on a U87 MG brain cancer cell line, including the dose- and time-dependent effects and the physicochemical and biological correlation between the RONS cascade and p38/mitogen-activated protein kinase (MAPK) signaling pathway, which contribute to apoptosis. The results indicated that soft plasma jets efficiently inhibit cell proliferation and induce apoptosis in U87 MG cells but have minimal effects on astrocytes. These findings revealed that soft plasma jets produce a potent cytotoxic effect via the initiation of cell cycle arrest and apoptosis. The production of reactive oxygen species (ROS) in cells was tested, and an intracellular ROS scavenger, N-acetyl cysteine (NAC), was examined. Our results suggested that soft plasma jets could potentially be used as an effective approach for anticancer therapy.

Disulfiram (DSF) has been studied as an anticancer drug and radiosensitizer. In our previous study, the therapeutic potential of DSF against atypical teratoid/rhabdoid tumor (AT/RT), one of the most aggressive forms of childhood cancer, had been confirmed using in vitro and in vivo studies. To develop more effective and safer therapy in AT/RT, we evaluated the sensitizing potential of DSF on radiation therapy (RT). The effect of DSF in low concentration alone and in combination with RT was investigated in vitro and vivo. Clonogenic assay, western blot analysis, autophagy assay and γ-H2AX foci staining were performed using several primary cultured AT/RT cells and cell lines. Also, in vivo study was performed using AT/RT orthotopic xenograft mouse model. Combination therapy with DSF and RT potently reduced clonogenicity and down-regulated protein expression of survivin and BCL2. The combination treatment strongly promoted the autophagic cell death and produced abundant γ-H2AX foci in all AT/RT cells. Moreover, the combination treatment significantly reduced the tumor growth and prolonged the survival rate compared to single treatment in AT/RT mouse model. Taken together, our results demonstrated that the combination therapy with DSF and RT has a synergistic therapeutic effect on AT/RT, suggesting a potential clinical application for AT/RT patients. Citation Format: Yeoung Eun Lee, Seung Ah Choi, Pil Ae Kwak, Kyu-Chang Wang, Ji Hoon Phi, Ji Yeoun Lee, Sangjoon Chong, Youn Joo Moon, Anshika Jangra, Kyeung Min Joo, Seung-Ki Kim. Combined disulfiram and radiation therapy against atypical teratoid/rhabdoid tumor. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3056.