In vitro cell and tissue models are playing essential roles in the identification of active pharmaceutical ingredients. Though HepG2 cells have attractive profiles over primary hepatocytes in the availability and viability retention, the expression of metabolizing enzymes is quite low. In the current study, three‐dimensional (3D) HepG2 spheroids with smaller sizes of 150 μm (3Ds) and bigger sizes of 300 μm (3Db) are engineered using injectable fiber fragments as the substrate. In contrast to two‐dimensional (2D) culture, the enzyme activities for drug metabolisms are restored in 3Ds and the pathophysiological profiles of tumor tissues are rebuilt in 3Db spheroids. Compared with spheroid culture without fiber fragments, 3Ds spheroids show higher activities of metabolizing enzymes (CYP3A4, CYP2A9, and phase II) and higher sensitivities to enzyme inducers (rifampicin and glutathione) and inhibitors (ketoconazole and probenecid). The drug clearance and toxicity to 3Ds spheroids predict better the clinical observations and drug–drug interactions. In addition, compared to scaffold‐free spheroid culture, stronger expressions of E‐cadherin and hypoxia‐inducible factor‐1α (HIF‐1α) and higher fibronectin secretions are determined in 3Db spheroids, displaying apparent hypoxic and apoptotic regions similar to those found in solid tumors. In contrast to the overestimated drug toxicity in other systems, the infiltrations of free drug and drug‐loaded micelles are apparently restricted in 3Db spheroids, exhibiting drug resistance just like in tumor tissues. Thus, this study demonstrates HepG2 spheroids with different sizes as predictable and physiologically relevant models for high‐throughput screening of drug metabolism and tumor infiltration.

中文翻译：

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使用可注射的纤维片段工程化 HepG2 球体作为药物代谢和肿瘤浸润的可预测模型。

体外细胞和组织模型在活性药物成分的鉴定中发挥着重要作用。尽管 HepG2 细胞在可用性和活力保留方面比原代肝细胞具有吸引力，但代谢酶的表达非常低。在当前的研究中，使用可注射纤维碎片作为基质设计了尺寸较小的 150 μm (3Ds) 和较大尺寸的 300 μm (3Db) 的三维 (3D) HepG2 球体。与二维 (2D) 培养相反，药物代谢的酶活性在 3D 中恢复，肿瘤组织的病理生理学特征在 3Db 球体中重建。与不含纤维碎片的球体培养物相比，3Ds 球体显示出更高的代谢酶（CYP3A4、CYP2A9、和 II 期）以及对酶诱导剂（利福平和谷胱甘肽）和抑制剂（酮康唑和丙磺舒）的更高敏感性。药物清除率和对 3Ds 球体的毒性可以更好地预测临床观察和药物 - 药物相互作用。此外，与无支架的球体培养相比，3Db 球体中 E-钙粘蛋白和缺氧诱导因子-1α (HIF-1α) 的表达更强，纤连蛋白分泌更多，显示出明显的缺氧和凋亡区域，类似于实体瘤。与其他系统中高估的药物毒性相反，游离药物和载药胶束的浸润显然在 3Db 球体中受到限制，就像在肿瘤组织中一样表现出耐药性。因此，