Ou Yu, Xu Shuya, Zhu Dandan, Yang Xuegan
School of Life Science and Technology, China Pharmaceutical University, Nanjing, China.
PLoS One. 2014 Jan 23;9(1):e87223. doi: 10.1371/journal.pone.0087223. eCollection 2014.
The present study aims to investigate the pharmacological effect of the exopolysaccharides from Aphanothece halophytica GR02 (EPSAH) on the HeLa human cervical cancer cell line. HeLa cells were cultured in RPMI-1640-10% FBS medium containing with or without different concentrations of EPSAH. Cell viability was assessed by methylthiazol tetrazolium (MTT) assay. Cell apoptosis was elevated with Wright-Giemsa staining, AO/EB double staining, and DNA fragmentation assay. Apoptosis-associated molecules from cultured HeLa cells were quantified using Western blot analysis. Our results suggest that EPASH induces apoptosis in HeLa cells by targeting a master unfolded protein response (UPR) regulator Grp78. Grp78 further promotes the expression of CHOP and downregulates expression of survivin, which leads to activate mitochondria-mediated downstream molecules and p53-survivin pathway, resulting in caspase-3 activation and causing apoptosis. These findings provide important clues for further evaluating the potential potency of EPSAH for use in cancer therapy.
本研究旨在探讨盐生隐球藻GR02胞外多糖（EPSAH）对人宫颈癌HeLa细胞系的药理作用。将HeLa细胞培养于含有或不含有不同浓度EPSAH的RPMI-1640-10%胎牛血清培养基中。通过甲基噻唑四氮唑（MTT）法评估细胞活力。采用瑞氏-吉姆萨染色、AO/EB双染和DNA片段化分析检测细胞凋亡情况。利用蛋白质免疫印迹分析对培养的HeLa细胞中凋亡相关分子进行定量分析。我们的结果表明，EPASH通过靶向未折叠蛋白反应（UPR）的主要调节因子Grp78诱导HeLa细胞凋亡。Grp78进一步促进CHOP的表达并下调survivin的表达，从而激活线粒体介导的下游分子和p53-survivin通路，导致caspase-3激活并引发凋亡。这些发现为进一步评估EPSAH在癌症治疗中的潜在效力提供了重要线索。
