Bromopyruvate mediates autophagy and cardiolipin degradation to monolyso-cardiolipin in GL15 glioblastoma cells.
The GL15 glioblastoma cell line undergoes viability loss upon treatment with bromopyruvate. The biochemical mechanisms triggered by the antiglycolytic agent indicate the activation of an autophagic pathway. Acridine orange stains acidic intracellular vesicles already 60 min after bromopyruvate treatment, whereas autophagosomes engulfing electron dense material are well evidenced 18 h later. The autophagic process is accompanied by the expression of the early autophagosomal marker Atg5 and by LC3-II formation, a late biochemical marker associated with autophagosomes. In agreement with the autophagic route activation, the inhibitory and the activator Akt and ERK signaling pathways are depressed and enhanced, respectively. In spite of the energetic collapse suffered by bromopyruvate-treated cells, MALDI-TOF mass spectrometry lipid analysis does not evidence a decrease of the major phospholipids, in accordance with the need of phospholipids for autophagosomal membranes biogenesis. Contrarily, mitochondrial cardiolipin decreases, accompanied by monolyso-cardiolipin formation and complete cytochrome c degradation, events that could target mitochondria to autophagy. However, in our experimental conditions cytochrome c degradation seems to be independent of the autophagic process.
Department of Internal Medicine, Laboratory of Biochemistry, University of Perugia, Via del Giochetto, 06122 Perugia, Italy.
Magdalena
M
Davidescu
Miriam
M
Sciaccaluga
Lara
L
Macchioni
Roberto
R
Angelini
Patrizia
P
Lopalco
Maria Grazia
MG
Rambotti
Rita
R
Roberti
Angela
A
Corcelli
Emilia
E
Castigli
Lanfranco
L
Corazzi
D000165:Acridine Orange; D018906:Antineoplastic Agents, Alkylating / Q000494:pharmacology*; D001343:Autophagy / Q000187:drug effects*; D000071187:Autophagy-Related Protein 5; D015153:Blotting, Western; D002308:Cardiolipins / Q000378:metabolism*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects*; D022162:Cytoplasmic Vesicles / Q000378:metabolism; D005909:Glioblastoma / Q000378:metabolism*; D006801:Humans; D046529:Microscopy, Electron, Transmission; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D011773:Pyruvates / Q000494:pharmacology*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
C502778:ATG5 protein, human; D018906:Antineoplastic Agents, Alkylating; D000071187:Autophagy-Related Protein 5; D002308:Cardiolipins; D008869:Microtubule-Associated Proteins; D011773:Pyruvates; C017092:bromopyruvate; D000165:Acridine Orange