Increased levels of mitochondrial DNA in an etoposide-resistant human monocytic leukaemia cell line (THP-1/E).
Electron microscopic observations of THP-1/E (an etoposide-resistant human monocytic leukaemia cell line) showed a remarkable change of mitochondrial structure. Mitochondria were swollen and cristae were relatively intact. There was no difference in the activity of cytochrome oxidase, an enzyme which contains three subunits coded by mitochondrial DNA (mtDNA) between THP-1/E and THP-1 (the parent cell of THP-1/E). No measurable quantitative change of mitochondrial RNA was observed, but the level of mtDNA in THP-1/E was increased by a factor of about 4 compared with that of mtDNA in THP-1. These results suggest that, on acquisition of resistance to etoposide, some factors affect mitochondria, change its morphology and amplify its DNA.
Tokue
Y
Y
Department of Internal Medicine, The Research Institute for Tuberculosis and Cancer, Sendai, Japan.
Saijo
Y
Y
Satoh
K
K
Motomiya
M
M
D015152:Blotting, Northern; D015139:Blotting, Southern; D004272:DNA, Mitochondrial / Q000032:analysis* / Q000648:ultrastructure; D004351:Drug Resistance / Q000235:genetics; D005047:Etoposide / Q000627:therapeutic use; D005784:Gene Amplification; D006801:Humans; D007948:Leukemia, Monocytic, Acute / Q000188:drug therapy / Q000473:pathology*; D008854:Microscopy, Electron; D012333:RNA, Messenger / Q000032:analysis; D014407:Tumor Cells, Cultured
D004272:DNA, Mitochondrial; D012333:RNA, Messenger; D005047:Etoposide