title: Mitochondria-targeted plastoquinone derivatives as tools to interrupt execution of the aging program. 3. Inhibitory effect of SkQ1 on tumor development from p53-deficient cells.
abstract: It was proposed that increased level of mitochondrial reactive oxygen species (ROS), mediating execution of the aging program of an organism, could also be critical for neoplastic transformation and tumorigenesis. This proposal was addressed using new mitochondria-targeted antioxidant SkQ1 (10-(6'-plastoquinonyl) decyltriphenylphosphonium) that scavenges ROS in mitochondria at nanomolar concentrations. We found that diet supplementation with SkQ1 (5 nmol/kg per day) suppressed spontaneous development of tumors (predominantly lymphomas) in p53(-/-) mice. The same dose of SkQ1 inhibited the growth of human colon carcinoma HCT116/p53(-/-) xenografts in athymic mice. Growth of tumor xenografts of human HPV-16-associated cervical carcinoma SiHa was affected by SkQ1 only slightly, but survival of tumor-bearing animals was increased. It was also shown that SkQ1 inhibited the tumor cell proliferation, which was demonstrated for HCT116 p53(-/-) and SiHa cells in culture. Moreover, SkQ1 induced differentiation of various tumor cells in vitro. Coordinated SkQ1-initiated changes in cell shape, cytoskeleton organization, and E-cadherin-positive intercellular contacts were observed in epithelial tumor cells. In Ras- and SV40-transformed fibroblasts, SkQ1 was found to initiate reversal of morphological transformation of a malignant type, restoring actin stress fibers and focal adhesion contacts. SkQ1 suppressed angiogenesis in Matrigel implants, indicating that mitochondrial ROS could be important for tumor angiogenesis. This effect, however, was less pronounced in HCT116/p53(-/-) tumor xenografts. We have also shown that SkQ1 and related positively charged antioxidants are substrates of the P-glycoprotein multidrug resistance pump. The lower anti-tumor effect and decreased intracellular accumulation of SkQ1, found in the case of HCT116 xenografts bearing mutant forms of p53, could be related to a higher level of P-glycoprotein. The effects of traditional antioxidant N-acetyl-L-cysteine (NAC) on tumor growth and tumor cell phenotype were similar to the effects of SkQ1 but more than 1,000,000 times higher doses of NAC than those of SkQ1 were required. Extremely high efficiency of SkQ1, related to its accumulation in the mitochondrial membrane, indicates that mitochondrial ROS production is critical for tumorigenesis at least in some animal models.
authors.affiliation: Blokhin Russian Cancer Research Center, Russian Academy of Medical Sciences, Moscow, Russia.
authors.forename: L S
authors.initials: LS
authors.lastname: Agapova
authors.forename: B V
authors.initials: BV
authors.lastname: Chernyak
authors.forename: L V
authors.initials: LV
authors.lastname: Domnina
authors.forename: V B
authors.initials: VB
authors.lastname: Dugina
authors.forename: A Yu
authors.initials: AY
authors.lastname: Efimenko
authors.forename: E K
authors.initials: EK
authors.lastname: Fetisova
authors.forename: O Yu
authors.initials: OY
authors.lastname: Ivanova
authors.forename: N I
authors.initials: NI
authors.lastname: Kalinina
authors.forename: N V
authors.initials: NV
authors.lastname: Khromova
authors.forename: B P
authors.initials: BP
authors.lastname: Kopnin
authors.forename: P B
authors.initials: PB
authors.lastname: Kopnin
authors.forename: M V
authors.initials: MV
authors.lastname: Korotetskaya
authors.forename: M R
authors.initials: MR
authors.lastname: Lichinitser
authors.forename: A L
authors.initials: AL
authors.lastname: Lukashev
authors.forename: O Yu
authors.initials: OY
authors.lastname: Pletjushkina
authors.forename: E N
authors.initials: EN
authors.lastname: Popova
authors.forename: M V
authors.initials: MV
authors.lastname: Skulachev
authors.forename: G S
authors.initials: GS
authors.lastname: Shagieva
authors.forename: E V
authors.initials: EV
authors.lastname: Stepanova
authors.forename: E V
authors.initials: EV
authors.lastname: Titova
authors.forename: V A
authors.initials: VA
authors.lastname: Tkachuk
authors.forename: J M
authors.initials: JM
authors.lastname: Vasiliev
authors.forename: V P
authors.initials: VP
authors.lastname: Skulachev
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics / Q000378:metabolism; D000375:Aging; D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002471:Cell Transformation, Neoplastic / Q000187:drug effects; D002478:Cells, Cultured; D005260:Female; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008819:Mice, Nude; D008928:Mitochondria / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D009368:Neoplasm Transplantation; D009369:Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000503:physiopathology*; D009389:Neovascularization, Pathologic / Q000188:drug therapy; D010971:Plastoquinone / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism; D014183:Transplantation, Heterologous; D016159:Tumor Suppressor Protein p53 / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism
chemical_list: C532038:10-(6'-plastoquinonyl)decyltriphenylphosphonium; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D017382:Reactive Oxygen Species; D016159:Tumor Suppressor Protein p53; D010971:Plastoquinone