Ito H, Seyama Y, Kubota S
Department of Physiological Chemistry and Metabolism, Graduate School of Medicine, University of Tokyo, Japan.
Biochem Biophys Res Commun. 2001 May 4;283(2):297-302. doi: 10.1006/bbrc.2001.4833.
Matrix metalloprotease-2 (MMP-2) plays a pivotal role in cancer invasion and metastasis. Invasive human rhabdomyosarcoma cells (RD) secrete proMMP-2. We recently reported that anti-alpha3 integrin antibody induced the activated form of MMP-2 and enhanced proMMP-2 secretion by RD cells with concomitant enhancement of RD cell invasion. Since recent studies showed that calreticulin interacts with integrin alpha subunit, we hypothesized that calreticulin may be involved in signal transduction of anti-alpha3 integrin antibody-mediated MMP-2 secretion and activation. Here we demonstrate that anti-alpha3 integrin antibody induced a transient enhanced interaction of calreticulin with alpha3 integrin. Transfection of antisense oligonucleotides of calreticulin in RD cells abrogated the interaction between calreticulin and alpha3 integrin, and completely suppressed activation of MMP-2 and enhanced secretion of proMMP-2 induced by anti-alpha3 integrin antibody. Transient overexpression of calreticulin cDNA in RD cells significantly increased secretion of proMMP-2. The results demonstrate for the first time that calreticulin is directly involved in MMP-2 secretion and activation.
基质金属蛋白酶-2（MMP-2）在癌症侵袭和转移中起关键作用。侵袭性人横纹肌肉瘤细胞（RD）分泌前MMP-2。我们最近报道，抗α3整合素抗体诱导MMP-2的活化形式，并增强RD细胞的前MMP-2分泌，同时增强RD细胞的侵袭。由于最近的研究表明钙网蛋白与整合素α亚基相互作用，我们推测钙网蛋白可能参与抗α3整合素抗体介导的MMP-2分泌和激活的信号转导。在此我们证明，抗α3整合素抗体诱导钙网蛋白与α3整合素的短暂增强相互作用。在RD细胞中转染钙网蛋白的反义寡核苷酸消除了钙网蛋白与α3整合素之间的相互作用，并完全抑制了抗α3整合素抗体诱导的MMP-2活化和前MMP-2分泌增强。在RD细胞中短暂过表达钙网蛋白cDNA显著增加了前MMP-2的分泌。结果首次证明钙网蛋白直接参与MMP-2的分泌和激活。
