title: [Apoptosis mechanism in human chronic myelogenous leukemia K562 cells induced by tetra-arsenic tetra-sulfide].
abstract: To explore the effects of tetra-arsenic tetra-sulfide (As(4)S(4)) in treatment of human chronic myelogenous leukemia K562 cells and its mechanism, trypan blue staining and microculture MTS assay were used to measure the effects of As(4)S(4) on growth inhibition of K562 cells; the morphologic change was determined by Wright's staining assay. The apoptosis rate and cell cycle were detected by flow cytometry; the changes of transcript and protein level were determined by real-time quantitative RT-PCR and Western blot analysis, respectively. The results indicated that As(4)S(4) had significant cytotoxicity on K562 cells. At the concentration of 0.5 micromol/L, the cell viability decreased significantly after being cultured with As(4)S(4) for 24 hours. When the concentration was lower than 0.1 micromol/L, As(4)S(4) had a little effect on K562 cells. The effect of As(4)S(4) on K562 was time- and concentration- dependent. After being cultured with As(4)S(4) at the concentration of 1.0 micromol/L for 24 to 48 hours, K562 cells displayed typical morphological changes of apoptosis. At a concentration greater than or equal to 1.0 micromol/L, As(4)S(4) could induce apoptosis significantly. After 12 hours of incubation with 1.0 micromol/L As(4)S(4), the apoptosis rate increased from (3.47 +/- 0.42)% to (6.16 +/- 0.98%). At the same time, the percentage of cells in G(1) phase decreased from (69.65 +/- 3.24)% to (50.53 +/- 2.86)%, whereas the percentage of cells in G(2)/M phase increased from (9.56 +/- 2.51)% to (12.91 +/- 2.13)%. The mRNA level of Bcl-X(L) and the protein level of pAkt were down-regulated after the inhibition of As(4)S(4), while the mRNA expression of Bcl-2, Bad and Bax had no change. Both of the transcript and protein level of bcr-abl had no change after incubation with As(4)S(4). It is concluded that As(4)S(4) can inhibit the growth of K562 cells efficiently through inducing apoptosis and cell cycle arrest. It seems that As(4)S(4) interferes with pAkt pathway and down-regulates Bcl-X(L), which may be involved in the response of K562 to this agent.
authors.affiliation: Department of Hematology and Oncology, Xinhua Hospital, Shanghai Children's Medical Center, The Shanghai Second Medical University, China.
authors.forename: Qi-Dong
authors.initials: QD
authors.lastname: Ye
authors.forename: Long-Jun
authors.initials: LJ
authors.lastname: Gu
authors.forename: Yan-Xia
authors.initials: YX
authors.lastname: Zhao
authors.forename: Jin-Cai
authors.initials: JC
authors.lastname: Zhao
authors.forename: Wen-Gao
authors.initials: WG
authors.lastname: Chen
authors.forename: Bei
authors.initials: B
authors.lastname: Zhang
authors.forename: Li-Min
authors.initials: LM
authors.lastname: Jiang
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D001152:Arsenicals / Q000737:chemistry / Q000494:pharmacology*; D015153:Blotting, Western; D002453:Cell Cycle / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D006801:Humans; D020014:K562 Cells; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013440:Sulfides / Q000737:chemistry / Q000494:pharmacology*; D013997:Time Factors; D051020:bcl-X Protein / Q000235:genetics / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D001152:Arsenicals; D012333:RNA, Messenger; D013440:Sulfides; D051020:bcl-X Protein; D051057:Proto-Oncogene Proteins c-akt