Resistance of mtDNA-depleted cells to apoptosis.
Cells lacking mitochondrial genome (defined as rho(0)) are useful models in studies on cancer, aging, mitochondrial diseases and apoptosis, but several of their functional aspects have been poorly characterized. Using different clones of rho(0) cells derived from the human osteosarcoma line 143B, we have tested the effects of different apoptogenic molecules such as staurosporine (STS), doxorubicin, daunomycin and quercetin, and have analyzed apoptosis, mitochondrial membrane potential (MMP), levels of oxygen free radicals, reduced glutathione (GSH) content, and expression of P-glycoprotein (P-gp). When compared to parental cells, rho(0) cells resulted much less sensitive to apoptosis. MMP was well maintained in rho(0) cells, and remained unchanged after adding apoptogenic agents, and did not change after treatment with molecules able to depolarize mitochondria such as valinomycin. After adding STS, the production of reactive oxygen species was similar in both cell types, but rho(0) cells maintained higher levels of GSH. In rho(0) cells, P-gp was strongly over-expressed both at mRNA and protein level, and its functionality was higher. The resistance to apoptosis of rho(0) cells could be not only due to an increased scavenger capacity of GSH, but also due to a selection of multidrug resistant cells that hyperexpress P-gp.
Ferraresi
Roberta
R
Department of Biomedical Sciences, University of Modena and Reggio Emilia, Modena, Italy.
Troiano
Leonarda
L
Pinti
Marcello
M
Roat
Erika
E
Lugli
Enrico
E
Quaglino
Daniela
D
Taverna
Daniela
D
Bellizzi
Dina
D
Passarino
Giuseppe
G
Cossarizza
Andrea
A
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000096:biosynthesis / Q000378:metabolism; D017209:Apoptosis / Q000502:physiology*; D045744:Cell Line, Tumor; D004272:DNA, Mitochondrial / Q000378:metabolism*; D005609:Free Radicals / Q000378:metabolism; D015870:Gene Expression; D005978:Glutathione / Q000096:biosynthesis; D006801:Humans; D053078:Membrane Potential, Mitochondrial / Q000502:physiology; D046529:Microscopy, Electron, Transmission; D008928:Mitochondria / Q000378:metabolism* / Q000648:ultrastructure*; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D004272:DNA, Mitochondrial; D005609:Free Radicals; D005978:Glutathione; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D012333:RNA, Messenger; C421109:multidrug resistance-associated protein 1