erbB3 recruitment of insulin receptor substrate 1 modulates insulin-like growth factor receptor signalling in oestrogen receptor-positive breast cancer cell lines
erbB3 recruitment of insulin receptor substrate 1 modulates insulin-like growth factor receptor signalling in oestrogen receptor-positive breast cancer cell lines
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DOI：
10.1186/bcr3018
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发表时间：
2011-01-01
影响因子：
7.4
通讯作者：
Hutcheson, Iain R.
中科院分区：
文献类型：
--
作者：
Knowlden, Janice M.;Gee, Julia M. W.;Hutcheson, Iain R.
简介：最近，我们报道了胰岛素受体底物1（IRS-1），经典的胰岛素样生长因子I型受体（IGF-IR）的衔接蛋白，与表皮生长因子受体在雌激素受体（ER）阳性（ER+）三苯氧胺耐药乳腺癌细胞。在这项研究中，我们研究了IRS-1是否也与另一个erbB受体家族成员erbB 3相关，以及这可能对三种ER+乳腺癌细胞系中IGF-IR信号传导产生什么影响。免疫沉淀和Western印迹分析用于检测MCF-7中erbB 3和IRS-1之间的潜在关联，T47 D和BT-474细胞在erbB 3/4配体heregulin beta 1（HRG beta 1）存在和不存在的情况下。随后，在这些细胞系中评估了选择性IGF-IR/IR抑制剂4-苯胺基-5-溴-2-[4-（2-羟基-3-（N，N-二甲基氨基）丙氧基）苯胺基]嘧啶对这种结合和HRG β 1信号传导的影响。ER+乳腺癌患者样本的一个小队列的免疫组化分析也进行了确定这种新的interaction.Results的潜在临床意义：免疫沉淀和蛋白质印迹分析揭示了erbB 3和IRS-1之间的相互作用在MCF-7，T47 D和BT-474细胞，与HRG β 1显着增强这种招聘和促进IRS-1磷酸化在Y 612。IRS-1参与MCF-7和T47 D细胞中的erbB 3信号传导，因为IRS-1敲低损害HRG β 1信号传导。重要的是，在MCF-7和T47 D细胞中，erbB 3募集IRS-1减少了IRS-1与IGF-IR的结合，而IGF-IR阻断增强了erbB 3-IRS-1的相互作用，并使两种细胞系对HRG β 1敏感，使HRG β 1超越IGF-IR阻断。因此，IRS-1信号的抑制增强了这些细胞中IGF-IR抑制的效果。这种新的相互作用可能具有临床意义，因为对小ER+乳腺肿瘤系列的免疫组化分析显示磷酸化IRS-1 Y 612表达与总erbB 3、磷酸化Akt和Ki-67表达之间存在显著正相关。IRS-1可在ER+乳腺癌细胞中被募集至IGF-IR和erbB 3，并且当这些受体被单独靶向时，这提供了适应性抗性机制。因此，共同靶向IGF-IR和erbB 3或IRS-1应该被证明是治疗ER+乳腺癌的更有效的策略。
Introduction: Recently we reported that insulin receptor substrate 1 (IRS-1), classically an adaptor protein for the insulin-like growth factor type I receptor (IGF-IR), associates with the epidermal growth factor receptor in oestrogen receptor (ER)-positive (ER+) tamoxifen-resistant breast cancer cells. In this study, we examined whether IRS-1 also associates with another erbB receptor family member, erbB3, and what impact this might have on IGF-IR signalling in three ER+ breast cancer cell lines.Methods: Immunoprecipitation and Western blot analysis were utilised to examine the potential association between erbB3 and IRS-1 in MCF-7, T47D and BT-474 cells in the absence and presence of the erbB3/4 ligand heregulin beta 1 (HRG beta 1). Subsequently, the impact of a selective IGF-IR/IR inhibitor 4-anilino-5-bromo-2-[4-(2-hydroxy-3-(N, N-dimethylamino)propoxy)anilino]pyrimidine on this association and HRG beta 1 signalling was assessed in these cell lines. Immunohistochemical analysis of a small cohort of ER+ breast cancer patient samples was also performed to determine the potential clinical relevance of this novel interaction.Results: Immunoprecipitation and Western blot analysis revealed an interaction between erbB3 and IRS-1 in MCF-7, T47D and BT-474 cells, with HRG beta 1 significantly enhancing this recruitment and promoting IRS-1 phosphorylation at Y612. IRS-1 participates in erbB3 signalling in MCF-7 and T47D cells as IRS-1 knockdown impaired HRG beta 1 signalling. Importantly, recruitment of IRS-1 by erbB3 reduced IRS-1 association with IGF-IR in MCF-7 and T47D cells, whilst blockade of IGF-IR-enhanced erbB3-IRS-1 interaction and sensitised both cell lines to HRG beta 1, allowing HRG beta 1 to override IGF-IR blockade. Consequently, suppression of IRS-1 signalling enhanced the effects of IGF-IR inhibition in these cells. This novel interaction may have clinical relevance, as immunohistochemical analysis of a small ER+ breast tumour series revealed significant positive correlations between phosphorylated IRS-1 Y612 expression and total erbB3, phosphorylated Akt and Ki-67 expression.Conclusions: IRS-1 can be recruited to IGF-IR and erbB3 in ER+ breast cancer cells, and this provides an adaptive resistance mechanism when these receptors are targeted individually. Consequently, cotargeting IGF-IR and either erbB3 or IRS-1 should prove to be a more effective strategy for the treatment of ER+ breast cancer.