[Mechanism of G2/M blockage triggered by activated-Chk1 in regulation of drug-resistance in K562/A02 cell line].
The study was purposed to investigate the effect of phosphorylated-chk1 on cell cycle and apoptosis of human erythroleukemic cell line K562 and K562/A02, and to explore the mechanism of chk1 in regulation of drug-resistance of leukemia cells. After treatment with adrimycin for six hours, the cell cycle distribution was detected by flow cytometry; the Chk1mRNA expression was detected by RT-PCR and the Chk1 phosphorylation level was detected by Western blot. Under the condition of down-regulation of Chk1mRNA expression in cells transfected with Chk1 short hairpin RNA, the cell apoptosis rates were detected by flow-cytometry following adrimycin. The results indicated that the proportion of K562/A02 cell line in G2/M phase was (54.12 +/- 0.57)% at 6 hours after drug treatment, significantly higher than that of K562 cell line (36.99 +/- 1.28)%. No evident difference of the Chk1mRNA expression was observed between K562 and K562/A02 cell lines, while elevated Chk1 phosphorylation following DNA damage induced by adriamycin was observed in the K562/A02 cell line (0.79 +/- 0.56), significantly higher than that in K562 cell line (0.27 +/- 1.47). The cell apoptosis rate of the Chk1 shRNA group in K562/A02 cell line was 3.84-fold of blank vector group, but that in K562 cell line was 1.30-fold of blank vector group. It is concluded that the increased chk1 activity that delay the progress of cell cycle are associated with cellular resistance to adrimycin in the K562/A02 cell line.
Wang
Hai-Yan
HY
Department of Hematology, Yichang Central People Hospital, The First Clinical Medical College, Three Gorges University, Yichang 443003, China.
Zhang
Min
M
Zou
Ping
P
You
Yong
Y
Guo
Jing-Ming
JM
Tang
Xiao-Qiong
XQ
Zhao
Zhi-Gang
ZG
Wu
Yao-Hui
YH
D017209:Apoptosis / Q000502:physiology*; D000071877:Checkpoint Kinase 1; D004317:Doxorubicin / Q000494:pharmacology; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D016195:G2 Phase; D006801:Humans; D020014:K562 Cells; D008938:Mitosis; D010766:Phosphorylation; D011494:Protein Kinases / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D015398:Signal Transduction
D012333:RNA, Messenger; D004317:Doxorubicin; D011494:Protein Kinases; C000605867:CHEK1 protein, human; D000071877:Checkpoint Kinase 1