title: [P27(Kip1), cyclin E and endogenous TGF-beta1 changes in apoptosis of NB4 cells induced by As(2)O(3) and/or TGF-beta1 and their significance].
abstract: This study was aimed to investigate the effects of arsenic trioxide (As(2)O(3)) and/or transforming growth factor-beta1 (TGF-beta1)on cell apoptosis and the changes of P27(Kip1), cyclin E and endogenous TGF-beta1 mRNA levels in NB4 cells. As(2)O(3) cytotoxicity to NB4 cells and the IC(50) were assayed with MTT, the apoptotic morphological changes were observed by Wright-Giemsa staining; the cell cycle and apoptosis were detected with flow cytometry. Semiquantitative RT-PCR was used to examine P27(Kip1), cyclin E and endogenous TGF-beta1 mRNA levels. The results showed that the As(2)O(3) and TGF-beta1 significantly suppressed the growth of NB4 cells, and promoted the apoptosis of these cells. The growth inhibition and apoptosis of NB4 cells treated with As(2)O(3) were in dose-and time-dependent manners. IC(50) were about 12 micromol/L for 24 hours, about 5 micromol/L for 48 hours, and about 3 micromol/L for 72 hours respectively. Cell cycle arrest in NB4 cells was induced by As(2)O(3) and/or TGF-beta1. The arrest of NB4 cells treated by 5 micromol/L As(2)O(3) was in G(2)/M phase, and 5 ng/ml TGF-beta1 in G(1) phase. However, the arrest of NB4 cells caused by combination of As(2)O(3) and TGF-beta1 was in S phase. After treating with As(2)O(3), P27(Kip1) and endogenous TGF-beta1 mRNA expressions of NB4 cells were up-regulated, and cyclin E mRNA expression was down-regulated. When NB4 cells were treated with TGF-beta1 alone, P27(Kip1) and cyclin E mRNA expressions were the same as that treated by As(2)O(3). Exogenous TGF-beta1 enhanced the above effects of As(2)O(3) in combination group. It is concluded that As(2)O(3) and TGF-beta1 are able to induce apoptosis and cell cycle abnormal distribution in NB4 cells. As(2)O(3) and exogenous TGF-beta1 may up-regulate endogenous TGF-beta1, which induce apoptosis of NB4 cells through consequently high expression of P27(Kip1). TGF-beta1 may lead to cell cycle arrest by inhibiting the expression of cyclin E directly, or by the activity of cyclin E through the increased expression of P27(Kip1).
authors.affiliation: Department of Hematology, The First Affiliated Hospital, China Medical University, Shenyang 110001, China. ligan2@medmail.com.cn
authors.forename: Ying
authors.initials: Y
authors.lastname: Liang
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.forename: Yue
authors.initials: Y
authors.lastname: Wang
authors.forename: Xia
authors.initials: X
authors.lastname: Li
authors.forename: Ping-Ping
authors.initials: PP
authors.lastname: Wang
authors.forename: Bai-Xun
authors.initials: BX
authors.lastname: Wang
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D000077237:Arsenic Trioxide; D001152:Arsenicals / Q000494:pharmacology*; D045744:Cell Line, Tumor; D019927:Cyclin E / Q000378:metabolism*; D050760:Cyclin-Dependent Kinase Inhibitor p27 / Q000378:metabolism*; D006801:Humans; D015513:Oncogene Proteins / Q000378:metabolism*; D010087:Oxides / Q000494:pharmacology*; D053773:Transforming Growth Factor beta1 / Q000378:metabolism / Q000494:pharmacology*; D015854:Up-Regulation
chemical_list: D001152:Arsenicals; C475820:CCNE1 protein, human; C436291:CDKN1B protein, human; D019927:Cyclin E; D015513:Oncogene Proteins; D010087:Oxides; D053773:Transforming Growth Factor beta1; D050760:Cyclin-Dependent Kinase Inhibitor p27; D000077237:Arsenic Trioxide