title: [Mechanism of G2/M blockage triggered by activated-Chk1 in regulation of drug-resistance in K562/A02 cell line].
abstract: 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.
authors.affiliation: Department of Hematology, Yichang Central People Hospital, The First Clinical Medical College, Three Gorges University, Yichang 443003, China.
authors.forename: Hai-Yan
authors.initials: HY
authors.lastname: Wang
authors.forename: Min
authors.initials: M
authors.lastname: Zhang
authors.forename: Ping
authors.initials: P
authors.lastname: Zou
authors.forename: Yong
authors.initials: Y
authors.lastname: You
authors.forename: Jing-Ming
authors.initials: JM
authors.lastname: Guo
authors.forename: Xiao-Qiong
authors.initials: XQ
authors.lastname: Tang
authors.forename: Zhi-Gang
authors.initials: ZG
authors.lastname: Zhao
authors.forename: Yao-Hui
authors.initials: YH
authors.lastname: Wu
mesh_terms: 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
chemical_list: D012333:RNA, Messenger; D004317:Doxorubicin; D011494:Protein Kinases; C000605867:CHEK1 protein, human; D000071877:Checkpoint Kinase 1