title: Effects of methotrexate on the viscoelastic properties of single cells probed by atomic force microscopy.
abstract: Methotrexate is a commonly used anti-cancer chemotherapy drug. Cellular mechanical properties are fundamental parameters that reflect the physiological state of a cell. However, so far the role of cellular mechanical properties in the actions of methotrexate is still unclear. In recent years, probing the behaviors of single cells with the use of atomic force microscopy (AFM) has contributed much to the field of cell biomechanics. In this work, with the use of AFM, the effects of methotrexate on the viscoelastic properties of four types of cells were quantitatively investigated. The inhibitory and cytotoxic effects of methotrexate on the proliferation of cells were observed by optical and fluorescence microscopy. AFM indenting was used to measure the changes of cellular viscoelastic properties (Young's modulus and relaxation time) by using both conical tip and spherical tip, quantitatively showing that the stimulation of methotrexate resulted in a significant decrease of both cellular Young's modulus and relaxation times. The morphological changes of cells induced by methotrexate were visualized by AFM imaging. The study improves our understanding of methotrexate action and offers a novel way to quantify drug actions at the single-cell level by measuring cellular viscoelastic properties, which may have potential impacts on developing label-free methods for drug evaluation.
authors.affiliation: State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang, 110016, China.
authors.forename: Mi
authors.initials: M
authors.lastname: Li
authors.affiliation: State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang, 110016, China. lqliu@sia.cn.
authors.forename: Lianqing
authors.initials: L
authors.lastname: Liu
authors.affiliation: Department of Lymphoma, Affiliated Hospital of Military Medical Academy of Sciences, Beijing, 100071, China.
authors.forename: Xiubin
authors.initials: X
authors.lastname: Xiao
authors.affiliation: State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang, 110016, China. xin@egr.msu.edu.|Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI, 48824, USA. xin@egr.msu.edu.
authors.forename: Ning
authors.initials: N
authors.lastname: Xi
authors.affiliation: State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang, 110016, China.
authors.forename: Yuechao
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000818:Animals; D002460:Cell Line; D055119:Elastic Modulus / Q000187:drug effects*; D006801:Humans; D008727:Methotrexate / Q000494:pharmacology*; D051379:Mice; D018625:Microscopy, Atomic Force; D059010:Single-Cell Analysis; D014783:Viscosity / Q000187:drug effects
chemical_list: D008727:Methotrexate
keywords: Atomic force microscopy; Cell; Methotrexate; Relaxation time; Viscoelastic properties; Young’s modulus