Nitroxyl Antioxidant TPPA-TEMPO Increases the Efficacy of Antitumor Therapy on the Model of Transplantable Mouse Tumor

Nitroxyl antioxidant 4-triphenylphosphonioacetamido-2,2,6,6-tetramethylpiperidine-1-oxyl (TPPA-TEMPO) was synthesized from 4-chloroacetamido-2,2,6,6-tetramethylpiperidine-1-oxyl chloride and triphenylphosphine. Systemic administration of TPPA-TEMPO in the subtoxic dose to mice with lymphosarcoma inhibited tumor growth, but did not prolong animal lifespan. Combined treatment with TPPA-TEMPO and cyclophosphamide increased the effi cacy of antitumor therapy: it prolonged animal lifespan and increased the number of recovered mice.