三氧化二砷对人胃癌耐药细胞系SGC7901/ADM耐药逆转及凋亡诱导作用的探讨

  目的   体外实验研究三氧化二砷(As₂O₃)对人胃癌阿霉素耐药细胞株(SGC7901/ADM)的逆转耐药机制。   方法   MTT法检测磷酸化ERK(p-ERK)激动剂G-CSF作用前后As₂O₃的逆转耐药倍数; 免疫细胞化学法测定As₂O₃及G-CSF作用前后SGC7901/ADM细胞内Ras和p-ERK的变化; 流式细胞仪测定G-CSF和As₂O₃干预后SGC7901/ADM的细胞周期和凋亡率。   结果   SGC7901/ADM对ADM耐药, As₂O₃可逆转耐药, 其中0.5μmol/L As₂O₃作用48 h后逆转耐药倍数约为6.29。G-CSF干预后, 逆转耐药倍数降至4.72;SGC7901/ADM中Ras表达高于亲本细胞株SGC7901/S, 而p-ERK无明显差异, As₂O₃可下调Ras及p-ERK的表达。G-CSF干预后, As₂O₃下调Ras及p-ERK表达的能力较干预前显著降低。0.1μmol/L和0.5μmol/L As₂O₃组的G₀~G₁期细胞比例和凋亡率均显著高于各个对照组; G-CSF干预后同一剂量的As₂O₃组G₀~G₁期细胞及凋亡率较干预前均显著降低。   结论   As₂O₃可逆转人胃癌耐药细胞株SGC7901/ADM对ADM的耐药作用, 其机制与下调Ras/p-ERK信号传导通路中Ras、磷酸化ERK的表达有关。

N,N-bis(cyclohexanol)amine aryl esters: the discovery of a new class of highly potent inhibitors of transporter-dependent multidrug resistance(MDR)

  Objective   The aim of this in vitro study is to assess the reversing effects of arsenic trioxide(As₂O₃) on multi-drug-resistance(MDR) of SGC7901/adriamycin(ADM) and determine the molecular mechanism associated with Ras/p-ERK downregulation in human gastric cancer cells.   Methods   The reversing effects of As₂O₃ before and after the treatment with an ERK agonist were determined by methyl thiazolyl tetrazolium assay.The molecular mechanism involved was further studied by examining the expressions of Ras and phosphorylated p-ERK by immunocytochemical assay.The process was repeated in pre-and post-intervention of As₂O₃ and granulocyte colony stimulating factor(G-CSF), respectively.Changes in the cell cycle and apoptotic rates were determined by flow cytometry.   Results   SGC7901/ADM was resistant to ADM, and As₂O₃ could reverse the drug resistance.After the treatment of As₂O₃ at a dose of 0.5 μmol/L for 48 h, the the multiple of reversed drug resistance was about 6.29 approximately, which was greater compared with that of the normal cells.After administration of As₂O₃, the IC50decreased dramatically, which shows that As₂O₃ could reverse MDR.After the G-CSF intervention, the multiple of the reversing effects was only 4.72.Immunocytochemical assay showed higher expressions of Ras in SGC7901/ADM than in the parental cell line SGC7901/S.No obvious difference in the p-ERK expressions of these cell lines was observed. As₂O₃ could decrease both Ras and p-ERK expressions(q-test, P < 0.01).After pre-treatment with the ERK agonist, Ras and p-ERK expressions decreased(t-test, P < 0.01).Flow cytometry indicated that the proportion of G₀-G₁ cells and apoptosis rate were higher in the As₂O₃ –treated group(0.1 and 0.5 μmol/L) than in the control groups.And apoptotic rate of both the cells significantly decreased in the As₂O₃ group of the same dose after treatment of G-CSF.   Conclusion   As₂O₃ can reduce the MDR of gastric cancer in vitro via the Ras/p-ERK signaling transduction pathway.