BACKGROUND In vitro modelling of cancer cells is becoming more complex due to prevailing evidence of intimate interactions between cancer cells and their surrounding stroma. A co-culture system which consists of more than one cell type is physiologically more relevant and thus, could serve as a useful model for various biological studies. An assay that specifically detects the phenotypic changes of cancer cells in a multi-cellular system is lacking for nasopharyngeal carcinoma (NPC). RESULTS Here, we describe a luciferase/luciferin (XenoLuc) assay that could specifically measure changes in the proliferation of cancer cells in the co-culture system using two modified NPC patient-derived tumour xenograft (PDTXs) cells: Xeno284-gfp-luc2 and XenoB110-gfp-luc2. Through this assay, we are able to show that the growth of NPC xenograft cells in both two-dimensional (2D) and three-dimensional (3D) models was enhanced when co-cultured with normal human dermal fibroblasts (NHDFs). In addition, potential applications of this assay in in vitro drug or inhibitor screening experiments are also illustrated. CONCLUSIONS XenoLuc assay is specific, sensitive, rapid and cost-effective for measuring the growth of luciferase-expressing cells in a co- or multiple-culture system. This assay may also be adapted for tumour microenvironment studies as well as drug screening experiments in more complex 3D co-culture systems.

中文翻译：

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萤光素酶/萤光素细胞增殖（XenoLuc）分析技术的开发，用于在共培养系统中实时测量Gfp-Luc2修饰的细胞。

背景技术由于普遍存在癌细胞与其周围基质之间紧密相互作用的证据，因此癌细胞的体外建模变得越来越复杂。由多种细胞类型组成的共培养系统在生理上更相关，因此可以用作各种生物学研究的有用模型。鼻咽癌（NPC）缺乏一种能特异性检测多细胞系统中癌细胞表型变化的检测方法。结果在这里，我们描述了一种萤光素酶/萤光素（XenoLuc）测定法，该测定法可以使用两个改良的NPC患者来源的肿瘤异种移植物（PDTXs）细胞：Xeno284-gfp-luc2和XenoB110-gfp-luc2。通过这种检测，我们能够证明，与正常人真皮成纤维细胞（NHDFs）共培养时，二维（2D）和三维（3D）模型中NPC异种移植细胞的生长均得到增强。此外，还说明了该测定法在体外药物或抑制剂筛选实验中的潜在应用。结论XenoLuc测定法是特异性，灵敏，快速且具有成本效益的，可用于测量在共培养或多培养系统中表达萤光素酶的细胞的生长。该测定法还可适用于肿瘤微环境研究以及更复杂的3D共培养系统中的药物筛选实验。还说明了该测定法在体外药物或抑制剂筛选实验中的潜在应用。结论XenoLuc测定法是特异性，灵敏，快速且具有成本效益的，可用于测量在共培养或多培养系统中表达萤光素酶的细胞的生长。该测定法还可适用于肿瘤微环境研究以及更复杂的3D共培养系统中的药物筛选实验。还说明了该测定法在体外药物或抑制剂筛选实验中的潜在应用。结论XenoLuc测定法是特异性，灵敏，快速且具有成本效益的，可用于测量在共培养或多培养系统中表达萤光素酶的细胞的生长。该测定法还可适用于肿瘤微环境研究以及更复杂的3D共培养系统中的药物筛选实验。