title: Mitochondrial division inhibitor-1 induces mitochondrial hyperfusion and sensitizes human cancer cells to TRAIL-induced apoptosis.
abstract: Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising candidate for cancer treatment, but some cancer cell types are resistant to TRAIL cytotoxicity. Therefore, overcoming this resistance is necessary for effective TRAIL therapy. Mitochondrial morphology is important for the maintenance of cell function and survival, and is regulated by the delicate balance between fission and fusion. However, the role of mitochondrial morphology dynamics in TRAIL-induced apoptosis is unknown. Here we show that mitochondrial division inhibitor-1 (mdivi-1), an inhibitor of dynamin-related protein1 (Drp1), modulates mitochondrial morphology and TRAIL-induced apoptosis in human cancer cells. mdivi-1 treatment (≥12.5 µM) caused dose- and time‑dependent cell death in malignant melanoma, lung cancer and osteosarcoma cells, while sparing normal cells. mdivi-1 also sensitized cancer cells to TRAIL-induced apoptosis. This potentiation of apoptosis occurred through a caspase-depependent mechanism including the mitochondrial and endoplasmic reticulum (ER) stress pathways. Mdivi-1 potentiated mitochondrial oxidative stress, a major cause of mitochondrial and ER stresses, as evidenced by increases in mitochondrial reactive oxygen species levels, mitochondrial mass, and cardiolipin oxidation. Live cell fluorescence imaging using MitoTracker Red CMXRos revealed that Mdivi-1 caused substantial mitochondrial hyperfusion. Moreover, silencing of Drp1 expression also caused mitochondrial hyperfusion and sensitized cancer cells to TRAIL-induced apoptosis. Our results suggest that cancer cells are more vulnerable than normal cells to a perturbation in mitochondrial morphology dynamics and that this higher susceptibility can be exploited to selectively kill cancer cells and sensitize to TRAIL.
authors.affiliation: Innovative Therapy Research Group, Nihon University Research Institute of Medical Science, Nihon University School of Medicine, Tokyo 173-8610, Japan.
authors.forename: Mamoru
authors.initials: M
authors.lastname: Akita
authors.affiliation: Department of Dermatology, Nihon University Surugadai Hospital, Tokyo 101-8309, Japan.
authors.forename: Miki
authors.initials: M
authors.lastname: Suzuki-Karasaki
authors.affiliation: Innovative Therapy Research Group, Nihon University Research Institute of Medical Science, Nihon University School of Medicine, Tokyo 173-8610, Japan.
authors.forename: Kyoko
authors.initials: K
authors.lastname: Fujiwara
authors.affiliation: Department of Dermatology, Nihon University Surugadai Hospital, Tokyo 101-8309, Japan.
authors.forename: Chinatsu
authors.initials: C
authors.lastname: Nakagawa
authors.affiliation: Innovative Therapy Research Group, Nihon University Research Institute of Medical Science, Nihon University School of Medicine, Tokyo 173-8610, Japan.
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Soma
authors.affiliation: Department of Orthopedic Surgery, Nihon University School of Medicine, Tokyo 173-8610, Japan.
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Yoshida
authors.affiliation: Department of Dermatology, Nihon University Surugadai Hospital, Tokyo 101-8309, Japan.
authors.forename: Toyoko
authors.initials: T
authors.lastname: Ochiai
authors.affiliation: Department of Orthopedic Surgery, Nihon University School of Medicine, Tokyo 173-8610, Japan.
authors.forename: Yasuaki
authors.initials: Y
authors.lastname: Tokuhashi
authors.affiliation: Innovative Therapy Research Group, Nihon University Research Institute of Medical Science, Nihon University School of Medicine, Tokyo 173-8610, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Suzuki-Karasaki
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics; D053148:Caspase 3 / Q000378:metabolism; D045744:Cell Line, Tumor; D034281:Dynamins; D059865:Endoplasmic Reticulum Stress / Q000235:genetics*; D004789:Enzyme Activation; D020558:GTP Phosphohydrolases / Q000096:biosynthesis* / Q000235:genetics; D020868:Gene Silencing; D006801:Humans; D008545:Melanoma / Q000235:genetics* / Q000473:pathology; D053078:Membrane Potential, Mitochondrial / Q000235:genetics; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000096:biosynthesis* / Q000235:genetics; D008928:Mitochondria / Q000235:genetics* / Q000473:pathology; D024101:Mitochondrial Proteins / Q000096:biosynthesis* / Q000235:genetics; D017382:Reactive Oxygen Species / Q000378:metabolism; D053221:TNF-Related Apoptosis-Inducing Ligand / Q000235:genetics / Q000378:metabolism*
chemical_list: D008869:Microtubule-Associated Proteins; D024101:Mitochondrial Proteins; D017382:Reactive Oxygen Species; D053221:TNF-Related Apoptosis-Inducing Ligand; C505653:TNFSF10 protein, human; D053148:Caspase 3; D020558:GTP Phosphohydrolases; C110768:DNM1L protein, human; D034281:Dynamins