Izmir Biomedicine and Genome Center, Balcova, Izmir 35340, Turkey.
Department of Analytical Chemistry, Faculty of Pharmacy, Izmir Katip Celebi University, Cigli, Izmir 35620, Turkey.
ACS Nano. 2021 Jun 22;15(6):10710-10721. doi: 10.1021/acsnano.1c04031. Epub 2021 May 24.
Accessing cell growth on adhesive substrates is critical for identifying biophysical properties of cells and their therapeutic response to drug therapies. However, optical techniques have low sensitivity, and their reliability varies with cell type, whereas microfluidic technologies rely on cell suspension. In this paper, we introduced a plasmonic functional assay platform that can precisely measure cell weight and the dynamic change in real-time for adherent cells. Possessing this ability, our platform can determine growth rates of individual cells within only 10 min to map the growth profile of populations in short time intervals. The platform could successfully determine heterogeneity within the growth profile of populations and assess subpopulations exhibiting distinct growth profiles. As a proof of principle, we investigated the growth profile of MCF-7 cells and the effect of two intracellular metabolisms critical for their proliferation. We first investigated the negative effect of serum starvation on cell growth. We then studied ornithine decarboxylase (ODC) activity, a key enzyme which is involved in proliferation, and degraded under low osmolarity that inhibits cell growth. We successfully determined the significant distinction between growth profiles of MCF-7 cells and their ODC-overproducing variants that possess strong resistance to the negative effects of low osmolarity. We also demonstrated that an exogenous parameter, putrescine, could rescue cells from ODC inhibition under hypoosmotic conditions. In addition to the ability of accessing intracellular activities through measurements, our platform could also determine therapeutic behaviors of cancer cells in response to drug treatments. Here, we investigated difluoromethylornithine (DFMO), which has antitumor effects on MCF-7 cells by inhibiting ODC activity. We successfully demonstrated the susceptibility of MCF-7 cells to such drug treatment, while its DFMO-resistant subpopulation could survive in the presence of this antigrowth agent. By rapidly determining cell growth kinetics in small samples, our plasmonic platform may be of broad use to basic research and clinical applications.
在黏附底物上检测细胞生长对于确定细胞的生物物理特性及其对药物治疗的治疗反应至关重要。然而，光学技术的灵敏度较低，其可靠性因细胞类型而异，而微流控技术则依赖于细胞悬浮液。在本文中，我们引入了一种等离子体功能测定平台，该平台可以精确测量贴壁细胞的细胞重量并实时动态变化。凭借这种能力，我们的平台可以在仅 10 分钟内确定单个细胞的生长速率，从而在短时间间隔内绘制群体的生长曲线。该平台能够成功确定群体生长曲线中的异质性，并评估表现出不同生长曲线的亚群。作为原理验证，我们研究了 MCF-7 细胞的生长曲线及其对两种对其增殖至关重要的细胞内代谢物的影响。我们首先研究了血清饥饿对细胞生长的负面影响。然后，我们研究了鸟氨酸脱羧酶（ODC）的活性，这是一种关键酶，参与增殖，并且在低渗透压下降解，从而抑制细胞生长。我们成功地确定了 MCF-7 细胞及其 ODC 过表达变体的生长曲线之间的显着差异，后者对低渗透压的负面影响具有很强的抵抗力。我们还证明了外源性参数腐胺可以在低渗条件下挽救 ODC 抑制的细胞。除了通过测量来访问细胞内活动的能力外，我们的平台还可以确定癌细胞对药物治疗的治疗反应。在这里，我们研究了二氟甲基鸟氨酸（DFMO），它通过抑制 ODC 活性对 MCF-7 细胞具有抗肿瘤作用。我们成功地证明了 MCF-7 细胞对这种药物治疗的敏感性，而其对 DFMO 的抗性亚群可以在存在这种抗生长剂的情况下存活。通过快速确定小样本中的细胞生长动力学，我们的等离子体平台可能具有广泛的基础研究和临床应用价值。
