Effects of temperature and cellular interactions on the mechanics and morphology of human cancer cells investigated by atomic force microscopy.

Mi Li,Lianqing Liu,Xiubin Xiao,Yuechao Wang,Weijing Zhang,Ning Xi

doi:10.1007/s11427-015-4914-4

Abstract

Cell mechanics plays an important role in cellular physiological activities. Recent studies have shown that cellular mechanical properties are novel biomarkers for indicating the cell states. In this article, temperature-controllable atomic force microscopy (AFM) was applied to quantitatively investigate the effects of temperature and cellular interactions on the mechanics and morphology of human cancer cells. First, AFM indenting experiments were performed on six types of human cells to investigate the changes of cellular Young's modulus at different temperatures and the results showed that the mechanical responses to the changes of temperature were variable for different types of cancer cells. Second, AFM imaging experiments were performed to observe the morphological changes in living cells at different temperatures and the results showed the significant changes of cell morphology caused by the alterations of temperature. Finally, by co-culturing human cancer cells with human immune cells, the mechanical and morphological changes in cancer cells were investigated. The results showed that the co-culture of cancer cells and immune cells could cause the distinct mechanical changes in cancer cells, but no significant morphological differences were observed. The experimental results improved our understanding of the effects of temperature and cellular interactions on the mechanics and morphology of cancer cells.

Highlights

The past decade has seen substantial growth in the studies on how changes in the biomechanical and biophysical properties of cells influence, and are influenced by, the onset and progression of many human diseases [1], including cancer [2], malaria [3], diabetes [4], osteoarthritis [5], and asthma [6]
The effects of cellular interactions on the mechanics of cancer cells were investigated by measuring the mechanical properties of three types of human cancer cells (MCF-7, HeLa, and A549) which were co-cultured with two types of immune cells (Raji and Jurkat)
This work quantitatively investigated the effects of temperature and cellular interactions on the mechanical and morphological properties of human cancer cells with the use of atomic force microscopy (AFM)

Summary

Introduction

The past decade has seen substantial growth in the studies on how changes in the biomechanical and biophysical properties of cells influence, and are influenced by, the onset and progression of many human diseases [1], including cancer [2], malaria [3], diabetes [4], osteoarthritis [5], and asthma [6]. A comprehensive study on human breast tissues has shown that cell mechanics is an effective biomarker that can identify the different stages (normal tissue, benign lesion and invasive cancer) in the process of cancer development [10]. We know cancer cells interact with other cells (e.g., cancer-associated fibroblasts, vascular endothelial cells, and immune cells) to form a solid tumor during oncogenesis [15] It is unknown whether the interactions between cancer cells and other cells in the micro-environments will cause the changes of cell mechanical properties. The effects of cellular interactions on the mechanics of cancer cells were investigated by measuring the mechanical properties of three types of human cancer cells (MCF-7, HeLa, and A549) which were co-cultured with two types of immune cells (Raji and Jurkat). AFM imaging was carried out to observe the morphological changes in cancer cells after being co-cultured with immune cells

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Discussion

Conclusion