Contribution of sialidase NEU1 to suppression of metastasis of human colon cancer cells through desialylation of integrin β4
Contribution of sialidase NEU1 to suppression of metastasis of human colon cancer cells through desialylation of integrin β4
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DOI：
10.1038/onc.2008.471
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发表时间：
2009-03-05
期刊：
影响因子：
8
通讯作者：
Miyagi, T.
中科院分区：
文献类型：
--
作者：
Uemura, T.;Shiozaki, K.;Miyagi, T.
我们先前发现唾液酸酶Neu 1表达与小鼠癌细胞的转移潜力之间存在反比关系。为了阐明细胞事件的机制，人唾液酸酶基因NEU 1在结肠癌HT-29细胞中过表达或沉默。当NEU 1过表达细胞经脾注射到小鼠体内时，体内肝转移显著减少。NEU 1在体外抑制细胞迁移、侵袭和粘附，而沉默则导致相反的结果。NEU 1的主要分子变化之一是整合素β 4的唾液酸化降低，通过用抗整合素β 4抗体对免疫沉淀物进行PNA-和MAL-II-凝集素印迹来评估。去唾液酸化伴随着整合素磷酸化的减少，随后粘着斑激酶和Erk 1/2途径的减弱。此外，NEU 1引起基质金属蛋白酶-7的下调，其过表达与癌症转移相关。用GalNAc-α-O-苄基（O-糖基化的抑制剂）处理细胞显示出PNA阳性整联蛋白β 4增加，其磷酸化降低，表明从整联蛋白O-聚糖中去除唾液酸导致磷酸化降低。生物素化和免疫荧光染色显示一些NEU 1分子位于整合素可接近的细胞表面。这些结果表明，NEU 1在调节整合素β 4介导的信号传导中是重要的，从而导致转移的抑制。
We previously found an inverse relationship between sialidase Neu1 expression and metastatic potential of murine cancer cells. To elucidate the mechanism underlying the cellular events, the human sialidase gene NEU1 was overexpressed or silenced in colon cancer HT-29 cells. When NEU1-overexpressing cells were injected transsplenically into mice, in vivo liver metastasis was significantly reduced. NEU1 suppressed cell migration, invasion and adhesion in vitro, whereas the silencing resulted in the opposite. One of the major molecular changes by NEU1 was decreased sialylation of integrin beta 4, assessed by PNA- and MAL-II-lectin blotting of immunoprecipitates with anti-integrin beta 4 antibody. The desialylation was accompanied by decreased phosphorylation of the integrin followed by attenuation of focal adhesion kinase and Erk1/2 pathway. Moreover, NEU1 caused downregulation of matrix metalloproteinase-7, overexpression of which is associated with cancer metastasis. Treatment of the cells with GalNAc-alpha-O-benzyl, an inhibitor of O-glycosylation, showed increased PNA-positive integrin beta 4 with its decreased phosphorylation, indicating that sialic acid removal from the integrin O-glycans results in the decreased phosphorylation. Biotinylation and immunofluorescence staining exhibited some NEU1 molecules to be at the cell surface accessible to the integrin. These results suggest that NEU1 is important in regulation of integrin beta 4-mediated signaling, leading to suppression of metastasis.