Cohen B D, Kiener P A, Green J M, Foy L, Fell H P, Zhang K
Molecular Immunology Department, Bristol-Myers Squibb, Pharmaceutical Research Institute, Seattle Washington 98121, USA.
J Biol Chem. 1996 Nov 29;271(48):30897-903. doi: 10.1074/jbc.271.48.30897.
A collection of cell lines expressing each human epidermal growth factor receptor (HER) family member alone or in all pairwise combinations in a clone of NIH3T3 cells (3T3-7d) devoid of detectable epidermal growth factor receptor family members has been generated. Transformation, as measured by growth in soft agar, occurred only in the presence of appropriate ligand and only in cells expressing two different HER family members. Transfection of oncogenic neu (Tneu), conferred ligand-independent transformation only in cells which co-expressed HER1, HER3, or HER4, but not when expressed alone or with HER2. Cell lines were also tested for their ability to form tumors in animals. None of the cell lines expressing single HER family members was able to form tumors in animals with the exception of HER1, which was weakly tumorigenic. Although unable to form tumors when expressed alone, HER2 was tumorigenic when expressed with HER1 or HER3, but not HER4. Of all complexes analyzed, cells expressing HER1 + HER2 were the most aggressive. The relationship between HER1 activation, intracellular calcium fluxes, and phospholipase Cgamma1 activation is well established. We found that activation of HER1 was required for the induction of a calcium flux and the phosphorylation of phospholipase Cgamma1. These activities were independent of, and unaffected by, the co-expression of any other family member. Further, heregulin stimulation of all cell lines including those containing HER1 did not demonstrate any effect on intracellular calcium levels or phospholipase Cgamma1 phosphorylation. This demonstrates that heregulin induced cellular transformation by activating HER3- and HER4-containing complexes does not require the activation of either phospholipase Cgamma1 or the mobilization of intracellular calcium.
已构建了一组细胞系，它们在缺乏可检测表皮生长因子受体家族成员的NIH3T3细胞克隆（3T3 - 7d）中单独表达或两两组合表达每个人表皮生长因子受体（HER）家族成员。通过软琼脂生长测定的转化仅在存在适当配体时且仅在表达两种不同HER家族成员的细胞中发生。致癌性neu（Tneu）的转染仅在共表达HER1、HER3或HER4的细胞中赋予配体非依赖性转化，单独表达或与HER2一起表达时则无此作用。还测试了细胞系在动物体内形成肿瘤的能力。除了具有弱致瘤性的HER1外，表达单个HER家族成员的细胞系均不能在动物体内形成肿瘤。HER2单独表达时虽不能形成肿瘤，但与HER1或HER3一起表达时具有致瘤性，与HER4一起表达时则无。在所有分析的复合物中，表达HER1 + HER2的细胞最具侵袭性。HER1激活、细胞内钙通量和磷脂酶Cγ1激活之间的关系已得到充分证实。我们发现诱导钙通量和磷脂酶Cγ1磷酸化需要HER1激活。这些活性独立于任何其他家族成员的共表达且不受其影响。此外，包括含HER1细胞系在内的所有细胞系的heregulin刺激均未显示对细胞内钙水平或磷脂酶Cγ1磷酸化有任何影响。这表明heregulin通过激活含HER3和HER4的复合物诱导细胞转化并不需要磷脂酶Cγ1的激活或细胞内钙的动员。
