Expression of c-Met proto-oncogene in metastatic macrophage x melanoma fusion hybrids: Implication of its possible role in MSH-induced motility
Expression of c-Met proto-oncogene in metastatic macrophage x melanoma fusion hybrids: Implication of its possible role in MSH-induced motility
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DOI：
10.3727/000000003771013062
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发表时间：
2003-01-01
影响因子：
3.1
通讯作者：
Pawelek, J
中科院分区：
文献类型：
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作者：
Chakraborty, AK;Kolesnikova, N;Pawelek, J
先前的研究表明，正常巨噬细胞与Cloudman S91黑色素瘤细胞体外融合产生的大多数杂交体显示巨噬细胞特异性糖基化，特别是GnT-V活性增加，糖蛋白中beta1, 6分支形成，并伴有体内转移潜力增强和体外运动性增强。这些杂交种在黑色素细胞刺激激素（MSH）治疗后也表达了上调的黑素皮质素-1受体（MC1-R）活性，并表现出增加的运动性。在本报告中，我们发现msh介导的运动刺激是通过增强c-Met原癌基因的表达介导的。在转移性杂交种中，c-Met的表达是由MSH诱导的，在细胞中加入c-Met中和抗体可以抑制MSH诱导的细胞运动，但不能抑制细胞的基础运动。此外，通过添加肝细胞生长因子（HGF）重组蛋白（c-Met受体的同源配体）来消除趋化剂梯度浓度，可以降低msh诱导的运动性影响。在趋化室中加入阻断抗α hgf抗体也获得了类似的结果。再一次，转移性杂交细胞，而非转移性杂交细胞或亲本黑色素瘤细胞，对rHGF化学引诱剂表现出显著的运动反应，当细胞被MSH/异丁基甲基黄嘌呤（IBMX）刺激时，这种运动进一步被诱导。MSH/IBMX处理以及rHGF和纤维连接蛋白（FN）联合作为趋化剂，对这些杂种的运动性也有协同刺激作用。这些表明，MSH/ ibmx诱导的运动可能涉及c-Met途径以及细胞外基质(ECM)/整合素途径的合作方式。Ets-1，一种参与c-Met表达的转录因子，也被发现在暴露于MSH/IBMX后，在转移性杂交种中被诱导。根据c-Met及其相互作用蛋白在转移表型发展及其治疗干预中的作用，讨论了该结果的意义。
It was shown previously that a majority of hybrids produced by in vitro fusion of normal macrophages with Cloudman S91 melanoma cells displayed macrophage-specific glycosylation, especially increased GnT-V activity, beta1, 6 branch formation in glycoproteins, accompanied by enhanced metastatic potential in vivo and motility in vitro. These hybrids also express upregulated melanocortin-1 receptor (MC1-R) activity and exhibit increased motility after melanocyte-stimulating hormone (MSH) treatment. In this report, we show that MSH-mediated stimulation of motility is mediated through enhanced expression of c-Met proto-oncogene. In metastatic hybrids c-Met expression is induced by MSH, and addition of c-Met neutralizing antibody to cells inhibits MSH-induced motility but not the basal motility of the cells. Furthermore, abrogation of the chemoattractant gradient concentration by addition of hepatocyte growth factor (HGF) recombinant protein, a cognate ligand of c-Met receptor, reduces the MSH-induced effect on motility. A similar result was also obtained by the addition of blocking anti-alphaHGF antibody in the chemoattractant chamber. Again, the metastatic hybrids, but not the nonmetastatic hybrids or parental melanoma cells, showed significant motile response to rHGF chemoattractant, and that motility is further induced when cells were stimulated with MSH/isobutylmethyl xanthine (IBMX). Synergistic stimulation on motility was also observed with those hybrids treated with MSH/IBMX and when rHGF and fibronectin (FN), in combination, were used as chemoattractants. These indicate that MSH/IBMX-induced motility might involve c-Met pathways as well as extracellular matrix (ECM)/integrin pathways in a cooperative fashion. Ets-1, a transcription factor involved in the expression of c-Met, is also found to be induced in metastatic hybrids after exposure to MSH/IBMX. Implication of the result is discussed in light of the role of c-Met and its interacting proteins in the development of metastatic phenotypes and its therapeutic intervention.