Ex vivo drug screening refers to the out-of-body assessment of drug efficacy in patient derived vital tumor cells. The purpose of these methods is to enable functional testing of patient specific efficacy of anti-cancer therapeutics and personalized treatment strategies. Such approaches could prove powerful especially in context of rare cancers for which demonstration of novel therapies is difficult due to the low numbers of patients. Here, we report comparison of different ex vivo drug screening methods in a metastatic urachal adenocarcinoma, a rare and aggressive non-urothelial bladder malignancy that arises from the remnant embryologic urachus in adults. To compare the feasibility and results obtained with alternative ex vivo drug screening techniques, we used three different approaches; enzymatic cell viability assay of 2D cell cultures and image-based cytometry of 2D and 3D cell cultures in parallel. Vital tumor cells isolated from a biopsy obtained in context of a surgical debulking procedure were used for screening of 1160 drugs with the aim to evaluate patterns of efficacy in the urachal cancer cells. Dose response data from the enzymatic cell viability assay and the image-based assay of 2D cell cultures showed the best consistency. With 3D cell culture conditions, the proliferation rate of the tumor cells was slower and potency of several drugs was reduced even following growth rate normalization of the responses. MEK, mTOR, and MET inhibitors were identified as the most cytotoxic targeted drugs. Secondary validation analyses confirmed the efficacy of these drugs also with the new human urachal adenocarcinoma cell line (MISB18) established from the patient’s tumor. All the tested ex vivo drug screening methods captured the patient’s tumor cells’ sensitivity to drugs that could be associated with the oncogenic KRASG12V mutation found in the patient’s tumor cells. Specific drug classes however resulted in differential dose response profiles dependent on the used cell culture method indicating that the choice of assay could bias results from ex vivo drug screening assays for selected drug classes.

中文翻译：

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在罕见的转移性尿道癌中药物功效的离体建模。

体外药物筛选是指对源自患者的重要肿瘤细胞中药物功效的体外评估。这些方法的目的是能够对患者的抗癌疗法的特定功效和个性化治疗策略进行功能测试。这样的方法可能被证明是有效的，特别是在罕见癌症的背景下，由于患者人数少，难以证明新疗法。在这里，我们报告比较不同的体外药物筛选方法在转移性尿道腺癌中的发生。转移性尿道腺癌是一种罕见且侵袭性的非尿道上皮性恶性肿瘤，是由成年人残留的胚胎性尿ura引起的。为了比较用替代性体外药物筛选技术获得的可行性和结果，我们使用了三种不同的方法。并行进行2D细胞培养物的酶促细胞活力测定和2D和3D细胞培养物的基于图像的细胞计数。从通过手术减量手术获得的活检物中分离出的重要肿瘤细胞被用于筛选1160种药物，目的是评估在尿道癌细胞中的功效模式。来自酶促细胞活力测定和2D细胞培养物基于图像的测定的剂量反应数据显示出最佳的一致性。在3D细胞培养条件下，即使在响应的生长速率正常化后，肿瘤细胞的增殖速度也会变慢，并且几种药物的效力也会降低。MEK，mTOR和MET抑制剂被确定为最具细胞毒性的靶向药物。二次验证分析也证实了这些药物对从患者肿瘤中建立的新型人尿道腺癌细胞系（MISB18）的有效性。所有经过测试的离体药物筛选方法均捕获了患者肿瘤细胞对可能与患者肿瘤细胞中发现的致癌性KRASG12V突变相关的药物的敏感性。但是，特定药物类别会导致差异的剂量反应曲线，具体取决于所用的细胞培养方法，这表明检测方法的选择可能会偏离所选药物类别的离体药物筛选检测结果。