Bcl-2相关的永生基因4对胃癌干细胞自我更新能力的调控作用

Bcl-2 associated athanogene 4 regulates self-renewal in gastric cancer stem cells

摘要:

目的 探讨Bcl-2相关的永生基因4（Bcl-2 associated athanogene 4，BAG4）在胃癌干细胞（gastric cancer stem cells，GCSCs）自我更新能力中的调控作用。方法 采用成球培养法分离/富集GCSCs，并对其生物学特征进行鉴定。采用慢病毒干扰技术构建沉默BAG4表达的MGC803胃癌细胞系，以平板克隆形成和成球实验分别检测沉默BAG4对胃癌细胞克隆形成和成球能力的影响。结果 成球培养法成功分离/富集出球细胞（sphere cell，SC）。与普通单层贴壁细胞相比，MGC803-SC高表达干性相关基因Sox2、Oct4和Bmi1，具有更强的克隆形成能力（198±17 vs. 92±11，P<0.001），诱导分化后干性标志物CD44表达下降，在体外具有更强的侵袭能力（185±18 vs. 84±11，P<0.01）。上述实验结果证实MGC803-SC具有GCSCs特性。BAG4在GCSCs中的表达水平明显高于普通贴壁胃癌细胞，沉默BAG4明显降低胃癌细胞的克隆形成和成球能力。结论 沉默BAG4基因能有效抑制GCSCs的自我更新能力，有望成为胃癌靶向治疗的新靶标。

Abstract:

Objective To investigate the role of Bcl-2 associated athanogene 4（BAG4） in self-renewal capacity of gastric cancer stem cells（GCSCs）.Methods GCSCs were isolated/enriched using sphere forming culture system， and their biological characteristics were identified. BAG4-knockdown MGC803 gastric cancer cell lines were constructed by lentivirus interference technique. Colony and tumor sphere formation assay were used to estimate the effect of BAG4-knockdown on self-renewal capacity of gastric cancer in vitro.Results We successfully isolated/enriched sphere cells（SC） using sphere forming culture system. MGC803-SC showed higher expression level of stem-related genes Sox2， Oct4 and Bmi1 than normal adherent cells， and showed stronger clone-formation ability（198±17 vs. 92±11，P<0.001）. After induction of differentiation， the expression of CD44 decreased，and showed stronger invasion ability in vitro（185±18 vs. 84±11，P<0.01）. The above experimental results confirmed that MGC803-SC had GCSCs properties. The expression level of BAG4 in GCSCs was significantly higher than that in normal adherent gastric cancer cells.Conclusion Silencing BAG4 gene can effectively inhibit the self-renewal ability of GCSCs，suggesting that BAG4 might be a promising target for gastric cancer therapy.