For native breast cancer cell growth to be mimicked in vitro as spheroids, a well-defined matrix that mimics the tumor microenvironment is required. Finding a biomimetic material for 3D cell culture other than Matrigel has challenged the field. Because hyaluronan is naturally abundant in the tumor microenvironment and can be chemically modified, we synthesized a hyaluronan (HA) hydrogel with independently tunable mechanical and chemical properties for 3D culture of breast cancer cells. By modifying HA with distinct bioorthogonal functional groups, its mechanical properties are controlled by chemical cross-linking via oxime ligation, and its biochemical properties are controlled by grafting bioactive peptides via Diels–Alder chemistry. A series of hydrogels were screened in terms of stiffness and peptide composition for cancer spheroid formation. In the optimal hydrogel formulation, the 3D breast cancer spheroids showed decreased drug diffusion into their core and upregulation of cellular multidrug-resistant efflux pumps similar to what is observed in drug-resistant tumors. Our results highlight the potential of these tunable and well-defined gels in drug screening assays.

中文翻译：

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通过肟和Diels-Alder化学方法独立调节基于3D透明质酸的水凝胶的生化和力学性质，以培养乳腺癌球体

为了将天然乳腺癌细胞的生长模拟为球体，需要模拟肿瘤微环境的明确定义的基质。寻找一种不同于Matrigel的用于3D细胞培养的仿生材料对这个领域提出了挑战。由于透明质酸在肿瘤微环境中自然丰富，可以进行化学修饰，因此我们合成了透明质酸（HA）水凝胶，具有独立可调的机械和化学性质，可用于乳腺癌细胞的3D培养。通过用不同的生物正交官能团修饰HA，其机械性能通过肟连接通过化学交联来控制，而其生物化学性能通过通过Diels-Alder化学接枝生物活性肽来控制。根据用于癌症球体形成的硬度和肽组成筛选了一系列水凝胶。在最佳的水凝胶配方中，类似于在耐药性肿瘤中观察到的那样，3D乳腺癌球体显示出药物扩散到其核心中的减少和细胞多药耐药性外排泵的上调。我们的结果突出了这些可调性和明确定义的凝胶在药物筛选测定中的潜力。