Nerve growth factor cooperates with p185HER2 in activating growth of human breast carcinoma cells
Nerve growth factor cooperates with p185HER2 in activating growth of human breast carcinoma cells
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DOI：
10.1074/jbc.275.8.5388
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发表时间：
2000-02-25
影响因子：
4.8
通讯作者：
Ménard, S
中科院分区：
文献类型：
--
作者：
Tagliabue, E;Castiglioni, F;Ménard, S
已知神经生长因子（NGF）通过原TrkA活化对人乳腺癌细胞发挥促有丝分裂作用。RT-PCR检测14例乳腺癌标本和4株乳腺癌细胞系中12例有trkA基因表达，而细胞荧光和Western blot检测结果显示3株乳腺癌细胞系有trkA基因表达，3株阳性细胞系中仅有2株有NGF刺激生长。针对TrkA胞外结构域的抗体而不是TrkA磷酸化的抑制剂对NGF诱导的MAPK活化的抑制证明了MAPK活化需要NGF结合而不是原TrkA激酶活性，这表明另一种激酶的募集用于有丝分裂信号的传递。事实上，NGF诱导酪氨酸磷酸化并刺激HER家族激酶受体p185（HER 2）的激酶活性。TrkA磷酸化抑制剂不影响这种激活。此外，这两种受体通过针对原TrkA和p185（HER 2）的抗体共沉淀。用含有抗p185（HER 2）抗体序列并表达原TrkA的构建体转染的乳腺癌细胞系中p185（HER 2）表达的下调损害了NGF诱导的MAPK活化和增殖。这些数据共同表明，在表达低水平TrkA的细胞如乳腺癌细胞中，NGF必须募集其他过表达的受体如p185（HER 2），以产生可诱导乳腺癌细胞生长的生物信号。
Nerve growth factor (NGF) is known to exert a mitogenic effect on human breast cancer cells through proto-TrkA activation. Reverse transcriptase-PCR analysis of proto-TrkA expression in human breast carcinoma specimens and cell lines revealed trkA transcript in 12 of 14 human breast carcinoma specimens and in all of four cell lines tested, while cytofluorimetric and Western blot analysis indicated proto-TrkA expression in three of the four cell lines, NGF stimulated growth in only two of the three positive cell Lines. Inhibition of NGF-induced MAPK activation by an antibody directed against the extracellular domain of TrkA but not by an inhibitor of TrkA phosphorylation demonstrated the requirement of NGF binding but not of proto-TrkA kinase activity for MAPK activation, suggesting the recruitment of another kinase for transmission of the mitogenic signaling. Indeed, NGF induced tyrosine phosphorylation and stimulated kinase activity of p185(HER2), a kinase receptor of the HER family. A TrkA phosphorylation inhibitor did not affect this activation. Moreover, the two receptors were coprecipitated by antibodies directed against proto-TrkA and p185(HER2). Down-modulation of p185(HER2) expression in a breast carcinoma Line transfected with a construct containing an anti-p185(HER2) antibody sequence and expressing proto-TrkA impaired NGF-induced MAPK activation and proliferation. Together these data show that in cells expressing low levels of TrkA such as breast carcinoma cells, NGF must recruit other overexpressed receptors such as p185(HER2) in order to generate a biological signal that can induce breast cancer cell growth.