Department of Biomedical Engineering, The Ohio State University, Columbus, OH 43210, USA.
Biomater Sci. 2020 Sep 7;8(17):4821-4831. doi: 10.1039/d0bm00505c. Epub 2020 Aug 4.
Glioblastoma (GBM) is the most aggressive and deadly adult brain tumor, primarily because of its high infiltrative capacity and development of resistance to therapy. Although GBM cells are typically believed to migrate via mesenchymal (e.g., fibroblast-like) migration modes, amoeboid (e.g., leucocyte-like) migration modes have been identified and may constitute a salvage pathway. However, the mesenchymal to amoeboid transition (MAT) process in GB is not well characterized, most likely because most culture models induce MAT via pharmacological or genetic inhibition conditions that are far from physiological. In this study, we examined the ability of hyaluronic acid (HA) content in three-dimensional collagen (Col) hydrogels to induce MAT in U87 GBM cells. HA and Col are naturally-occurring components of the brain extracellular matrix (ECM). In pure Col gels, U87 cells displayed primarily mesenchymal behaviors, including elongated cell morphology, clustered actin and integrin expression, and crawling migration behaviors. Whereas an increasing population of cells displaying amoeboid behaviors, including rounded morphology, cortical actin expression, low/no integrin expression, and squeezing or gliding motility, were observed with increasing HA content (0.1-0.2 wt% in Col). Consistent with amoeboid migration, these behaviors were abrogated by ROCK inhibition with the non-specific small molecule inhibitor Y27632. Toward identification of histological MAT classification criteria, we also examined the correlation between cell and nuclear aspect ratio (AR) in Col and Col-HA gels, finding that nuclear AR has a small variance and is not correlated to cell AR in HA-rich gels. These results suggest that HA may regulate GBM cell motility in a ROCK-dependent manner.
胶质母细胞瘤（GBM）是最具侵袭性和致命性的成人脑肿瘤，主要是因为其高浸润能力和对治疗的耐药性发展。尽管通常认为 GBM 细胞通过间质（例如，成纤维细胞样）迁移模式迁移，但已经鉴定出阿米巴样（例如，白细胞样）迁移模式，并且可能构成挽救途径。然而，GB 中的间质到阿米巴样转变（MAT）过程尚未得到很好的描述，这很可能是因为大多数培养模型通过远非生理的药理学或遗传抑制条件诱导 MAT。在这项研究中，我们研究了透明质酸（HA）在三维胶原（Col）水凝胶中的含量对 U87 GBM 细胞中 MAT 的诱导能力。HA 和 Col 是大脑细胞外基质（ECM）的天然成分。在纯 Col 凝胶中，U87 细胞表现出主要的间质行为，包括伸长的细胞形态、聚集的肌动蛋白和整合素表达以及爬行迁移行为。然而，随着 HA 含量的增加（Col 中的 0.1-0.2wt%），观察到越来越多的细胞表现出阿米巴样行为，包括圆形形态、皮质肌动蛋白表达、低/无整合素表达以及挤压或滑行运动。与阿米巴样迁移一致，这些行为被 ROCK 抑制剂非特异性小分子抑制剂 Y27632 阻断。为了确定组织学 MAT 分类标准，我们还研究了 Col 和 Col-HA 凝胶中细胞和核纵横比（AR）之间的相关性，发现核 AR 方差较小，并且与富含 HA 的凝胶中的细胞 AR 不相关。这些结果表明，HA 可能以 ROCK 依赖性方式调节 GBM 细胞的运动。
