Increased expression of DNA-dependent protein kinase confers resistance to adriamycin.
Acquired resistance to adriamycin (ADR) in an HL60 cell line is shown to be accompanied by an increase in DNA-dependent protein kinase catalytic subunit (DNA-PKcs) at both the protein and mRNA levels (15-20-fold) and an overall 3-fold increase in DNA-PK enzyme activity. The other components of the DNA-PK Ku autoantigen complex, Ku70 and Ku80, were 3-fold increased and unchanged, respectively. Time dependent repair of ADR-induced DNA damage was measured by the neutral comet assay and found to be more efficient in the drug resistant cell line (HL60/ADR). Antisense RNA transfection reduced the protein expression of DNA-PKcs to 50% in HL60/ADR and partially reversed drug resistance. A fibroblast cell line from a severe combined immunodeficient (SCID) mouse was deficient in functional DNA-PKcs and showed increased sensitivity to ADR and other DNA damaging agents compared to wild type. These studies demonstrate that alteration in DNA-PK can contribute to chronic stress response leading to acquired drug resistance. The overexpression of DNA-PK is thus shown to be a novel cellular adaptation mechanistically contributing to the resistance of cancer cells to the anthracycline drug adriamycin, and as such, may have implications for its therapeutic use.
Shen
H
H
Department of Pharmacology, Fox Chase Cancer Center, 7701 Burholme Avenue, Philadelphia, PA 19111, USA.
Schultz
M
M
Kruh
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GD
Tew
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D000222:Adaptation, Physiological; D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology*; D034961:Antigens, Nuclear; D001483:Base Sequence; D002460:Cell Line; D004249:DNA Damage; D004265:DNA Helicases; D017931:DNA Primers / Q000235:genetics; D004260:DNA Repair; D051747:DNA-Activated Protein Kinase; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004317:Doxorubicin / Q000494:pharmacology*; D004351:Drug Resistance / Q000235:genetics / Q000502:physiology; D015870:Gene Expression; D018922:HL-60 Cells; D006801:Humans; D000072200:Ku Autoantigen; D051379:Mice; D016513:Mice, SCID; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D016133:Polymerase Chain Reaction; D011487:Protein Conformation; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016372:RNA, Antisense / Q000235:genetics; D014162:Transfection
D000903:Antibiotics, Antineoplastic; D034961:Antigens, Nuclear; D017931:DNA Primers; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D016372:RNA, Antisense; D004317:Doxorubicin; D051747:DNA-Activated Protein Kinase; C497263:PRKDC protein, human; D017346:Protein Serine-Threonine Kinases; D004265:DNA Helicases; C106893:XRCC5 protein, human; C000606509:Xrcc6 protein, human; C000606510:Xrcc6 protein, mouse; D000072200:Ku Autoantigen