title: DNA damage, lysosomal degradation and Bcl-xL deamidation in doxycycline- and minocycline-induced cell death in the K562 leukemic cell line.
abstract: We investigated mechanisms of cytotoxicity induced by doxycycline (doxy) and minocycline (mino) in the chronic myeloid leukemia K562 cell line. Doxy and mino induced cell death in exposure-dependent manner. While annexin V/propidium iodide staining was consistent with apoptosis, the morphological changes in Giemsa staining were more equivocal. A pancaspase inhibitor Z-VAD-FMK partially reverted cell death morphology, but concurrently completely prevented PARP cleavage. Mitochondrial involvement was detected as dissipation of mitochondrial membrane potential and cytochrome C release. DNA double strand breaks detected with γH2AX antibody and caspase-2 activation were found early after the treatment start, but caspase-3 activation was a late event. Decrement of Bcl-xL protein levels and electrophoretic shift of Bcl-xL molecule were induced by both drugs. Phosphorylation of Bcl-xL at serine 62 was ruled out. Similarly, Bcr/Abl tyrosine kinase levels were decreased. Lysosomal inhibitor chloroquine restored Bcl-xL and Bcr/Abl protein levels and inhibited caspase-3 activation. Thus, the cytotoxicity of doxy and mino in K562 cells is mediated by DNA damage, Bcl-xL deamidation and lysosomal degradation with activation of mitochondrial pathway of apoptosis.
authors.affiliation: Experimental Cancer Medicine (ECM), Clinical Research Center (KFC), Novum, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden. Electronic address: mona.fares@ki.se.
authors.forename: Mona
authors.initials: M
authors.lastname: Fares
authors.affiliation: Experimental Cancer Medicine (ECM), Clinical Research Center (KFC), Novum, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden. Electronic address: manuchehr.abedi-valugerdi@ki.se.
authors.forename: Manuchehr
authors.initials: M
authors.lastname: Abedi-Valugerdi
authors.affiliation: Experimental Cancer Medicine (ECM), Clinical Research Center (KFC), Novum, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden; Clinical Research Center (KFC), Novum, Karolinska University Hospital Huddinge, Stockholm, Sweden. Electronic address: moustapha.hassan@ki.se.
authors.forename: Moustapha
authors.initials: M
authors.lastname: Hassan
authors.affiliation: Experimental Cancer Medicine (ECM), Clinical Research Center (KFC), Novum, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden. Electronic address: zuzana.potacova@ki.se.
authors.forename: Zuzana
authors.initials: Z
authors.lastname: Potácová
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3 / Q000378:metabolism; D004249:DNA Damage / Q000187:drug effects*; D004318:Doxycycline / Q000494:pharmacology*; D004789:Enzyme Activation / Q000187:drug effects; D016044:Fusion Proteins, bcr-abl / Q000378:metabolism; D006801:Humans; D020014:K562 Cells; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D008911:Minocycline / Q000494:pharmacology*; D059748:Proteolysis / Q000187:drug effects; D051020:bcl-X Protein / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D000970:Antineoplastic Agents; D051020:bcl-X Protein; D016044:Fusion Proteins, bcr-abl; D053148:Caspase 3; D008911:Minocycline; D004318:Doxycycline
keywords: Apoptosis; Cell death; Doxycycline; K562 cell line; Minocycline