Demonstration of differences in drug resistance by direct testing of DNA excision repair activity following standard and liposomal daunorubicin exposure in normal paediatric marrow using high resolution CLSM.
BACKGROUND
High resolution Confocal Laser Scanning Microscopy (CLSM) may be applied to testing of drug resistance in vitro in clinical setting. Rapid analysis of DNA damage by precise quantitation of excised DNA in bone marrow samples exposed to potential treatment moieties directly after isolation but the relative sensitivity of the integrated method is as yet untested.


OBJECTIVE
To test the clinical applicability of SCGE/high resolution CLSM for differences in drug resistance in marrow cells.


METHODS
Cells from normal bone marrow samples were exposed for identical periods and at 4 concentrations to either 1 hour of standard Daunorubicin (.5, 1, 1.5, 2 micrograms/ml) or 8 hours DaunoXome (courtesy of NeXstar Inc, USA) (.05, .1, .15, .2 microgram/ml). After 2 and 6 hours recovery, cells were harvested for SCGE, randomization, analysis of tail length, total excised DNA and fragment size distribution using high resolution CLSM.


RESULTS
Tail length and fragment size distribution was not, but total excised DNA was significantly increased after 0.1 microgram/ml Liposomal Daunorubicin (DaunoXome) compared to 1.0 microgram/ml Daunorubicin.


CONCLUSIONS
SCGE/high resolution CLSM effectively demonstrated differences in Daunorubicin resistance of human marrow cells to alternative formulations. The method has potential for use in clinical testing of neoplastic cell drug resistance.
Lannon
C L
CL
Department of Pathology, Dalhousie University, IWK Grace Health Centre, Halifax, Nova Scotia, Canada.
Ball
L M
LM
Pyesmany
A F
AF
Yhap
M
M
Langley
G R
GR
van Velzen
D
D
D000903:Antibiotics, Antineoplastic / Q000008:administration & dosage / Q000633:toxicity*; D001854:Bone Marrow Cells / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D002478:Cells, Cultured; D002648:Child; D020552:Comet Assay / Q000379:methods*; D004249:DNA Damage; D004260:DNA Repair / Q000187:drug effects*; D003630:Daunorubicin / Q000008:administration & dosage / Q000633:toxicity*; D004337:Drug Carriers; D006801:Humans; D008081:Liposomes; D018613:Microscopy, Confocal / Q000379:methods*; D012016:Reference Values; D012680:Sensitivity and Specificity
D000903:Antibiotics, Antineoplastic; D004337:Drug Carriers; D008081:Liposomes; D003630:Daunorubicin