Activation of an ataxia telangiectasia mutation-dependent intra-S-phase checkpoint by anti-tumour drugs in HL-60 and human lymphoblastoid cells.
In yeast cells, the intra-S-phase checkpoint slows down the rate of DNA replication in response to DNA damage. Here we showed that a similar checkpoint mechanism is present and activated by anti-tumour drugs in HL-60 and Epstein-Barr virus (EBV)-transformed human lymphoblastoid cells. Using bromodeoxyuridine (BrdU) pulse labelling combined with two-dimensional flow cytometric analysis, we clearly visualized the cell-cycle progression of the BrdU-positive population (cells originally belonging to the S phase) and detected even subtle changes in S-phase progression induced by mild drug treatment conditions free of apoptosis. The DNA topoisomerase II inhibitors, doxorubicin and etoposide (250 nmol/l and 400 nmol/l, respectively, for 8 h), retained the BrdU-positive HL-60 cells in the latter half of S and G2/M positions, and the pyrimidine analogue anti-metabolite, cytosine beta-D-arabinofuranose (Ara-C; 50 nmol/l), kept them in early-to-late S phase after 8 h of incubation. Because 10 micromol/l of caffeine added 2 h later attenuated the S-phase retardation by these drugs in HL-60 cells, slowing of the S-phase progression should be actively regulated. Furthermore, two ataxia telangiectasia (AT)-derived lymphoblastoid cell lines were impaired in the doxorubicin-induced S-phase retardation, which indicated that the process is at least partially dependent on ataxia telangiectasia mutated (ATM) gene product. The inhibitory mechanism on S-phase progression elicited by anti-tumour drugs in HL-60 and lymphoblastoid cells may therefore correspond to the intra-S-phase checkpoint of the yeast cells.
Sugimoto
K
K
Department of Haematology, Juntendo University School of Medicine, Tokyo, Japan. ksugimot@med.juntendo.ac.jp
Tamayose
K
K
Takagi
M
M
Yamada
K
K
Sasaki
M
M
Mizutani
S
S
Oshimi
K
K
D000963:Antimetabolites / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000494:pharmacology*; D064007:Ataxia Telangiectasia Mutated Proteins; D001973:Bromodeoxyuridine; D002110:Caffeine / Q000494:pharmacology; D018797:Cell Cycle Proteins; D002461:Cell Line, Transformed; D003561:Cytarabine / Q000494:pharmacology; D004268:DNA-Binding Proteins; D004317:Doxorubicin / Q000494:pharmacology; D005047:Etoposide / Q000494:pharmacology; D005434:Flow Cytometry / Q000379:methods; D015870:Gene Expression / Q000187:drug effects; D018922:HL-60 Cells / Q000187:drug effects*; D006801:Humans; D009154:Mutation; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D017346:Protein Serine-Threonine Kinases / Q000235:genetics*; D016196:S Phase / Q000187:drug effects*; D015398:Signal Transduction / Q000187:drug effects*; D059005:Topoisomerase II Inhibitors; D025521:Tumor Suppressor Proteins
D000963:Antimetabolites; D000970:Antineoplastic Agents; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D010726:Phosphodiesterase Inhibitors; D059005:Topoisomerase II Inhibitors; D025521:Tumor Suppressor Proteins; D003561:Cytarabine; D002110:Caffeine; D005047:Etoposide; D004317:Doxorubicin; C576324:ATM protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; D017346:Protein Serine-Threonine Kinases; D001973:Bromodeoxyuridine