Towards a novel 3D cell culture model to test the therapeutic efficacy of Affimers in the treatment of HER2 overexpressing breast cancer

乳腺癌(BC)是女性中最常见的癌症。人类表皮受体2(HER2)在15-30%的BC中高表达，与腔内亚型相比预后较差。目前，曲妥珠单抗(Trastuzumab)用于治疗。小鼠模型一直是有价值的BC模型，然而，为了解决3R问题，希望减少、改进和取代它们在研究中的使用。在这里，我们正在研究一种新型的HER2+BC体外三维培养模型。HER2高表达细胞系BT-474在无基质培养液EPERFL中培养为球形细胞。球体显示出肿瘤的特征，如坏死核和3D结构，因此比2D培养模型更适合临床应用。然后在SeedEZ支架中培养细胞。这种支架是亲水性的，由玻璃纤维组成，可以在它们之间形成球体。SeedEZ与PerfusionPal一起培养，以更接近于体内肿瘤的环境。此外，还鉴定了与HER2结合的抗体替代蛋白支架Affimers，并将研究它们对HER2+细胞生长的抑制作用。这是为了创建一个完全人性化的3D模型，以测试和比较Affimers与Trastuzumab在治疗HER2+BC方面的疗效，潜在地减少对动物进行临床前药物测试的需要。

Breast cancer (BC) is the most commonly diagnosed cancer amongst women. Human epidermal receptor 2 (HER2) is overexpressed in 15-30 % of BC and is associated with poorer prognosis with comparison to the luminal subtypes. The monoclonal antibody (MAb) Trastuzumab is currently used for its treatment.Mouse models have and continue to be valuable models of BC, however, to address the 3 R's it is desirable to reduce, refine and replace their use in research. Here, a novel in vitro 3D culture model of HER2+ BC is being investigated. The HER2 overexpressing cell line BT-474 were cultured as spheroids in a matrix-free medium, epiFL. Spheroids show characteristics of a tumour such as a necrotic core and 3D structure so are more translational to the clinic than 2D culture models. Cells were then cultured in SeedEZ scaffolds. The scaffolds are hydrophilic consisting of glass fibers that allow spheroids to form in between them. SeedEZ were cultured with PerfusionPal to more closely mimic the environment of a tumour in vivo. Furthermore Affimers, an antibody replacement protein scaffold, that bind HER2 have been identified and their effects on inhibiting HER2+ cell growth will be studied. This is towards the creation of a fully humanised 3D model to test and compare the efficacy of Affimers in comparison to Trastuzumab in the treatment of HER2+ BC, potentially reducing the need for animals in preclinical drug testing.