The acquired drug chemoresistance represents the main challenge of the ovarian cancer treatment. In addition, the absence of an adequate in vitro model able to reproduce the native tumor environment can contribute to the poor success rate of pre‐clinical studies of new compounds. Three‐dimensional (3D) culture models have been recently used for drug screening purposes due to their ability to reproduce the main characteristics of in vivo solid tumors. Here we describe the establishment and characterization of 3D ovarian cancer spheroids using different adenocarcinoma tumor cell lines (SKOV‐3 and OVCAR‐3 cells) in two different 3D scaffold‐free methods: forced‐floating in ultra‐low attachment (ULA) plates and hanging drop (HD). Spheroids were evaluated in both 3D cultures in order to establish the best condition to perform the drug response analysis with Paclitaxel, a common drug used to treat ovarian cancer. SKOV‐3 and OVCAR‐3 spheroids with the desired characteristics (roundness close to 1.0 and diameter in the 200–500 μm range) were obtained using both methods after addition of the methylcellulose (MC) in the culture medium (0.25% and 0.5%, w/v). We also observed the presence of microvilli on the surface of the spheroids, higher presence of apoptotic cells and higher drug resistance, when compared with 2D cultures. The 3D cultures obtained seem to provide more reliable results in terms of drug response than those provided by 2D monolayer culture. The forced floating method was considered more suitable and straightforward to generate ovarian cancer spheroids for drug screening/cytotoxicity assays.

中文翻译：

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用于药物筛选试验的体外 3D 卵巢癌模型的建立和表征。

获得性药物耐药性是卵巢癌治疗的主要挑战。此外，缺乏能够重现天然肿瘤环境的足够体外模型可能导致新化合物临床前研究的成功率较低。三维 (3D) 培养模型最近已用于药物筛选目的，因为它们能够再现体内实体瘤的主要特征。在这里，我们描述了使用不同腺癌肿瘤细胞系（SKOV-3 和 OVCAR-3 细胞）在两种不同的 3D 无支架方法中建立和表征 3D 卵巢癌球体：在超低附着 (ULA) 板中强制漂浮和悬滴（高清）。在两种 3D 培养物中对球体进行了评估，以建立使用紫杉醇（一种用于治疗卵巢癌的常用药物）进行药物反应分析的最佳条件。在培养基中加入甲基纤维素 (MC)（0.25% 和 0.5%）后，使用这两种方法获得了具有所需特性（圆度接近 1.0，直径在 200-500 μm 范围内）的 SKOV-3 和 OVCAR-3 球体，w/v）。与 2D 培养相比，我们还观察到球体表面存在微绒毛、凋亡细胞的存在和耐药性更高。与 2D 单层培养物相比，获得的 3D 培养物似乎在药物反应方面提供了更可靠的结果。