MEDIATION OF NGF-STIMULATED EXTRACELLULAR-MATRIX INVASION BY THE HUMAN-MELANOMA LOW-AFFINITY P75 NEUROTROPHIN RECEPTOR - MELANOMA P75 FUNCTIONS INDEPENDENTLY OF TRKA
MEDIATION OF NGF-STIMULATED EXTRACELLULAR-MATRIX INVASION BY THE HUMAN-MELANOMA LOW-AFFINITY P75 NEUROTROPHIN RECEPTOR - MELANOMA P75 FUNCTIONS INDEPENDENTLY OF TRKA
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DOI：
10.1091/mbc.4.11.1205
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发表时间：
1993-11-01
影响因子：
3.3
通讯作者：
NICOLSON, GL
中科院分区：
文献类型：
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作者：
HERRMANN, JL;MENTER, DG;NICOLSON, GL
虽然低亲和力p75神经营养因子受体（p75(NTR)）的过表达通常与人类黑色素瘤进展的晚期有关，但这一发现的功能意义尚不清楚。我们研究了p75（NTR）在人类黑色素瘤细胞变体中的细胞表面表达程度是否决定了它们受神经生长因子（NGF）刺激的侵袭程度。用2.5S NGF处理MeWo黑色素瘤细胞或MeWo细胞的转移性自发小麦胚凝集素抗性变异亚群（70W），可通过重建的基底膜产生剂量依赖性的侵袭增强。这种效应在70W亚型中最为明显，该亚型在裸鼠中具有脑转移潜力，但在低转移性MeWo亚型中没有发现（3S5）。p75（NTR）的表达通过Northern blotting和i -125标记的与ngf刺激侵袭相关的细胞表面蛋白的免疫沉淀分析确定。通过Northern分析和RT-PCR分析，本研究中使用的MeWo黑色素瘤亚系不表达p140（原trkA） mRNA或包括p70（trkA）在内的任何p140（原trkA）变异转录本。因此，这些黑色素瘤细胞不会形成能够将ngf产生的信号转导到p140（原trka）细胞质底物的功能性p75-p140异二聚体或p140-p140同二聚体。这些细胞确实表达了真实的p145（trkC）转录本。然而，NGF并没有通过酪氨酸磷酸化的增加来催化激活p145（trkC）受体，如果p145（trkC）参与NGF建立的信号传导，那么就会出现这种情况。此外，发现ngf刺激嘌呤类似物敏感激酶活性与p75（NTR）共免疫沉淀。这种p75（NTR）相关激酶可能协调p75（NTR）配体相互作用引起的初始信号事件。在基质贴壁培养的人MeWo和70W而不是3S5黑色素瘤细胞中，添加2.5S浓度的NGF，使细胞表面p75（NTR）饱和，抑制了92-kDa IV型胶原酶的表达，并刺激了72-kDa IV型胶原酶的产生，其完全活性为68-kDa。在缺乏p140（原trka）的情况下，NGF对脑转移性70W黑色素瘤细胞金属蛋白酶表达的基质依赖性作用表明，低亲和力黑色素瘤p75（NTR）受体及其相关嘌呤类似物敏感激酶在信号传导中增强了富含NGF的基质微环境（如大脑）的基质渗透。
Although overexpression of the low-affinity p75 neurotrophin receptor (p75(NTR)) is, frequently associated with advanced stages of human melanoma progression, the functional significance of this finding is unknown. We examined whether the degree of cell surface expression of p75(NTR) in, human melanoma cell variants determines their extent of invasion stimulated by nerve growth factor (NGF). Treatment of MeWo melanoma cells or a metastatic spontaneous wheat germ agglutinin-resistant variant subline (70W) of MeWo cells with 2.5S NGF resulted in a dose-dependent enhancement of invasion through a reconstituted basement membrane. This effect was most pronounced with the 70W subline that exhibits brain-metastasizing potential in nude mice but was not found with a poorly metastatic MeWo variant subline (3S5). The expression of p75(NTR) as determined by Northern blotting and immunoprecipitation analysis of I-125-labeled cell surface proteins correlated with NGF-stimulated invasion. The MeWo melanoma sublines used in this study did not express p140(proto-trkA) mRNA or any p140(proto-trkA) variant transcripts including p70(trkA) as determined by Northern analysis and RT-PCR analysis. Thus, these melanoma cells would not be expected to form functional p75-p140 heterodimers or p140-p140 homodimers capable of transducing an NGF-generated signal to p140(proto-trkA) cytoplasmic substrates. These cells did express authentic p145(trkC) transcripts. However, NGF did not catalytically activate p145(trkC) receptors via increased tyrosine phosphorylation as would be expected if p145(trkC) participated in the signaling established by NGF. Furthermore, a NGF-stimulated purine-analogue-sensitive kinase activity was found to coimmunoprecipitate with p75(NTR). This p75(NTR)-associated kinase may coordinate initial signaling events evoked by p75(NTR) ligand interaction. Addition of 2.5S NGF, at concentrations that should saturate cell surface p75(NTR) to matrix-adherent cultures of human MeWo and 70W but not 3S5 melanoma cells suppressed the expression of 92-kDa type IV collagenase and stimulated the production of 72-kDa type IV collagenase in its fully active 68-kDa form. In the absence of p140(proto-trkA), the matrix-dependent effects of NGF on metalloproteinase expression of brain-metastatic 70W melanoma cells suggest a signaling role for the low-affinity melanoma p75(NTR) receptor and its associated purine-analogue-sensitive kinase in signaling enhanced matrix penetration of NGF-rich stromal microenvironments such as the brain.