Lysosomal nitric oxide determines transition from autophagy to ferroptosis after exposure to plasma-activated Ringer's lactate
Li Jiang, Hao Zheng, Qinying Lyu, Shotaro Hayashi, Kotaro Sato, Yoshitaka Sekido, Kae Nakamura, Hiromasa Tanaka, Kenji Ishikawa, Hiroaki Kajiyama, Masaaki Mizuno, Masaru Hori, Shinya Toyokuni
Abstract
Non-thermal plasma (NTP), an engineered technology to generate reactive species, induces ferroptosis and/or apoptosis specifically in various-type cancer cells. NTP-activated Ringer's lactate (PAL) is another modality for cancer therapy at preclinical stage. Here we found that PAL induces selective ferroptosis of malignant mesothelioma (MM) cells, where non-targeted metabolome screening identified upregulated citrulline-nitric oxide (.NO) cycle as a PAL target. .NO probe detected biphasic peaks transiently at PAL exposure with time-dependent increase, which was responsible for inducible . NO synthase (iNOS) overexpression through NF-κB activation. .NO and lipid peroxidation occupied lysosomes as a major compartment with increased TFEB expression. Not only ferrostatin-1 but inhibitors for . NO and/or iNOS could suppress this ferroptosis. PAL-induced ferroptosis accompanied autophagic process in the early phase, as demonstrated by an increase in essential amino acids, LC3B-II, p62 and LAMP1, transforming into the later phase with boosted lipid peroxidation. Therefore, .NO-mediated lysosomal impairment is central in PAL-induced ferroptosis.