Background Triple negative breast cancer (TNBC) is an aggressive subtype of breast cancer with limited therapeutic options. Epidermal growth factor receptor (EGFR) has been shown to be over-expressed in TNBC and represents a rational treatment target. Methods We examined single agent and combination effects for afatinib and dasatinib in TNBC. We then determined IC50 and combination index values using Calcusyn. Functional analysis of single and combination treatments was performed using reverse phase protein array and cell cycle analysis. Finally, we determined the anticancer effects of the combination in vivo. Results A total of 14 TNBC cell lines responded to afatinib with IC50 values ranging from 0.008 to 5.0 µM. Three cell lines, belonging to the basal-like subtype of TNBC, were sensitive to afatinib. The addition of afatinib enhanced response to the five other targeted therapies in HCC1937 and HDQP1 cells. The combination of afatinib with dasatinib caused the greatest growth inhibition in both cell lines. The afatinib/dasatinib combination was synergistic and/or additive in 13/14 TNBC cell lines. Combined afatinib/dasatinib treatment induced G1 cell cycle arrest. Reverse phase protein array results showed the afatinib/dasatinib combination resulted in efficient inhibition of both pERK(T202/T204) and pAkt(S473) signalling in BT20 cells, which was associated with the greatest antiproliferative effects. High baseline levels of pSrc(Y416) and pMAPK(p38) correlated with sensitivity to afatinib, whereas low levels of B-cell lymphoma 2 (Bcl2) and mammalian target of rapamycin (mTOR) correlated with synergistic growth inhibition by combined afatinib and dasatinib treatment. In vivo, the combination treatment inhibited tumour growth in a HCC1806 xenograft model. Conclusions We demonstrate that afatinib combined with dasatinib has potential clinical activity in TNBC but warrants further preclinical investigation.

中文翻译：

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联合靶向 EGFR 和 SRC 作为治疗三阴性乳腺癌的潜在新治疗方法。

背景 三阴性乳腺癌 (TNBC) 是一种侵袭性乳腺癌亚型，治疗选择有限。表皮生长因子受体 (EGFR) 已被证明在 TNBC 中过度表达，并代表了一个合理的治疗目标。方法 我们检查了阿法替尼和达沙替尼在 TNBC 中的单药和联合用药效果。然后我们使用 Calcusyn 确定 IC50 和组合指数值。使用反相蛋白质阵列和细胞周期分析进行单一和联合治疗的功能分析。最后，我们确定了该组合在体内的抗癌作用。结果共有 14 个 TNBC 细胞系对阿法替尼有反应，IC50 值范围为 0.008 至 5.0 µM。三个属于 TNBC 基底样亚型的细胞系对阿法替尼敏感。添加阿法替尼增强了对 HCC1937 和 HDQP1 细胞中其他五种靶向治疗的反应。阿法替尼与达沙替尼的组合在两种细胞系中引起最大的生长抑制。阿法替尼/达沙替尼组合在 13/14 TNBC 细胞系中具有协同作用和/或相加作用。阿法替尼/达沙替尼联合治疗诱导 G1 细胞周期停滞。反相蛋白阵列结果显示，阿法替尼/达沙替尼组合可有效抑制 BT20 细胞中的 pERK(T202/T204) 和 pAkt(S473) 信号传导，这与最大的抗增殖作用相关。pSrc(Y416) 和 pMAPK(p38) 的高基线水平与对阿法替尼的敏感性相关，而低水平的 B 细胞淋巴瘤 2 (Bcl2) 和哺乳动物雷帕霉素靶蛋白 (mTOR) 与阿法替尼和达沙替尼联合治疗的协同生长抑制相关。在体内，联合治疗抑制了 HCC1806 异种移植模型中的肿瘤生长。结论 我们证明阿法替尼联合达沙替尼在 TNBC 中具有潜在的临床活性，但需要进一步的临床前研究。