Zhao Xingkai, Ma Shuo, Liu Ning, Liu Jiakun, Wang Wenbo
Department of Orthopaedic Surgery, The First Affiliated Hospital of Harbin Medical University, Harbin, 150001, People's Republic of China.
Tumour Biol. 2015 Jul;36(7):5255-63. doi: 10.1007/s13277-015-3185-9. Epub 2015 Feb 11.
In this study, we isolated and purified one homogeneous polysaccharide (TRP) from the fruiting bodies of Trametes robiniophila Murrill, and its average molecular weight was estimated to be 8.7 × 10(4) Da. Monosaccharide composition analysis by gas chromatography (GC) indicated that TRP was composed of glucose, galactose, and arabinose in the molar ratio of 4.2:1.10:1.06. Particularly, we evaluated the anti-cancer efficacy of TRP on human osteosarcoma U-2 OS cells in vitro and associated possible molecular mechanism. Our result provided the first evidence that treatment of U-2 OS cells with TRP resulted in a dose- and time-dependent inhibitory effect on cell proliferation of U-2 OS cells and caused apoptotic death. Moreover, TRP induced the apoptosis of U-2 OS cells via a mitochondria-dependent pathway, as evidenced by an increase in Bax/Bcl-2 ratio, a loss of mitochondrial membrane potential (Δψm), release of cytochrome c from the mitochondria to the cytosol, activation of caspase-9 and caspase-3, and cleavage of poly(ADP-ribose) polymerase (PARP) in U-2 OS cells. In addition, overexpression of metadherin (MTDH), one carcinogene, was inhibited in U-2 OS cells after exposure to TRP for 24 h. Our findings suggested that TRP inhibited the proliferation of human osteosarcoma cancer cells by promoting apoptosis through the intrinsic mitochondrial pathway, as well as inhibition of MTDH expression.
在本研究中，我们从槐栓菌子实体中分离并纯化出一种均一多糖（TRP），其平均分子量估计为8.7×10⁴ Da。气相色谱（GC）分析单糖组成表明，TRP由葡萄糖、半乳糖和阿拉伯糖组成，摩尔比为4.2:1.10:1.06。特别地，我们评估了TRP对人骨肉瘤U-2 OS细胞的体外抗癌疗效及相关可能的分子机制。我们的结果首次证明，用TRP处理U-2 OS细胞会对其细胞增殖产生剂量和时间依赖性抑制作用，并导致凋亡死亡。此外，TRP通过线粒体依赖性途径诱导U-2 OS细胞凋亡，这在U-2 OS细胞中表现为Bax/Bcl-2比值增加、线粒体膜电位（Δψm）丧失、细胞色素c从线粒体释放到细胞质、caspase-9和caspase-3激活以及聚（ADP-核糖）聚合酶（PARP）裂解。此外，致癌基因metadherin（MTDH）在U-2 OS细胞暴露于TRP 24小时后表达受到抑制。我们的研究结果表明，TRP通过内在线粒体途径促进凋亡以及抑制MTDH表达来抑制人骨肉瘤癌细胞的增殖。
