Bid-overexpression regulates proliferation and phosphorylation of Akt and MAPKs in response to etoposide-induced DNA damage in hepatocellular carcinoma cells
Bid-overexpression regulates proliferation and phosphorylation of Akt and MAPKs in response to etoposide-induced DNA damage in hepatocellular carcinoma cells
复制标题
Bid 过表达可调节 Akt 和 MAPK 的增殖和磷酸化，以响应肝细胞癌细胞中依托泊苷诱导的 DNA 损伤。
DOI：
10.2147/ott.s36087
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发表时间：
2012-01-01
影响因子：
4
通讯作者：
Song, Gang
中科院分区：
文献类型：
--
作者：
Li, Yuanyue;Dai, Congjie;Song, Gang
背景：越来越多的证据支持bh3相互作用结构域死亡激动剂（Bid）在DNA损伤反应中起双重作用。然而，在依托泊苷诱导的DNA损伤中，Bid对肝细胞癌（HCC）细胞增殖的影响尚未得到充分的研究。方法：使用稳定的Bid过表达HCC细胞系Bid/PLC/PRF/5，在依托泊苷诱导的DNA损伤中，过表达Bid可促进细胞活力丧失。MTT[3-（4,5-二甲基噻唑-2-基）-2,5-二苯基溴化四唑]-和BrdU（5'-溴-2'-脱氧尿苷）-标记试验显示，依托泊苷抑制的HCC细胞以浓度和时间依赖的方式生长。Western blotting分析依托泊苷诱导的DNA损伤对Akt和丝裂原活化蛋白激酶（MAPKs）磷酸化的影响。结果：100 μ M依托泊苷在对照载体和Bid/PLC/PRF/5细胞上48 h的MTT法和brdu法的存活率分别为71% +/- 0.75%和59% +/- 0.60%，brdu法的存活率分别为85% +/- 0.08%和63% +/- 0.14%。此外，在高剂量依托泊苷的作用下，Bid的过度表达使细胞对凋亡敏感（造成不可修复的损伤）。低剂量依托泊苷（可修复损伤）对细胞增殖影响不大。此外，我们还研究了Akt和MAPKs的磷酸化状态。在依托泊苷诱导的DNA损伤中，Bid的过表达抑制Akt的激活。与Akt类似，bid过表达可降低磷酸化p38和磷酸化c-Jun的水平。相反，ERK1/2磷酸化水平维持在较高水平，尤其是在Bid/PLC/PRF/5细胞中。结论：综上所述，Bid过表达抑制Akt、p38和c-Jun的活化，促进etopo苷诱导的ERK1/2的活化，提示ERK1/2活化的促进可能对Bid介导的etopo苷诱导的HCC DNA损伤有负面影响。
Background: Growing evidence supports BH3-interacting domain death agonist (Bid) playing a dual role in DNA damage response. However, the effects of Bid on hepatocellular carcinoma (HCC) cell proliferation in response to etoposide-induced DNA damage have not been sufficiently investigated.Methods: Using a stable Bid-overexpression HCC cell line, Bid/PLC/PRF/5, overexpression of Bid promoted loss of viability in response to etoposide-induced DNA damage. MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide]- and BrdU (5'-bromo-2'-deoxyuridine)- labeling assays revealed that etoposide-inhibited HCC cells grew in concentration- and time-dependent manners. The phosphorylations of Akt and mitogen-activated protein kinases (MAPKs) in response to etoposide-induced DNA damage were analyzed by Western blotting.Results: The survival rates of 100 mu M etoposide on the cells with control vector and Bid/PLC/PRF/5 at 48 hours amounted to 71% +/- 0.75% and 59% +/- 0.60% with MTT assay, and similar results of 85% +/- 0.08% and 63% +/- 0.14% with BrdU-labeling assay respectively. Moreover, overexpression of Bid sensitized the cells to apoptosis at a high dose of etoposide (causing irreparable damage). However, it had little effect on the proliferation at a low dose of etoposide (repairable damage). Furthermore, the phosphorylation status of Akt and MAPKs were investigated. Overexpression of Bid suppressed the activation of Akt with respect to etoposideinduced DNA damage. Similar to Akt, the levels of phosphorylated p38 and phosphorylated c-Jun were attenuated by Bid-overexpression. On the contrary, the level of phosphorylated ERK1/2 was sustained at a high level, especially in Bid/PLC/PRF/5 cells.Conclusion: Taken together, these results suggest that overexpression of Bid suppressed the activation of Akt, p38, and c-Jun, and promoted the activation of ERK1/2 induced by etoposide, suggesting that the promotion of ERK1/2 activation may have a negative effect on Bid-mediated HCC DNA damage induced by etoposide.