Atomic force microscopy imaging of live mammalian cells

et al. 2015

Acta Pharmacol Sin

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Knowledge of the nanoscale changes that take place in individual cells in response to a drug is useful for understanding the drug action. However, due to the lack of adequate techniques, such knowledge was scarce until the advent of atomic force microscopy (AFM), which is a multifunctional tool for investigating cellular behavior with nanometer resolution under near-physiological conditions. In the past decade, researchers have applied AFM to monitor the morphological and mechanical dynamics of individual cells following drug stimulation, yielding considerable novel insight into how the drug molecules affect an individual cell at the nanoscale. In this article we summarize the representative applications of AFM in characterization of drug actions on cell membrane, including topographic imaging, elasticity measurements, molecular interaction quantification, native membrane protein imaging and manipulation, etc. The challenges that are hampering the further development of AFM for studies of cellular activities are aslo discussed.

Section: Wwwchinapharcom LI M Et Almentioning

confidence: 99%

Section: Wwwchinapharcom LI M Et Almentioning

confidence: 99%

Nanoscale monitoring of drug actions on cell membrane using atomic force microscopy

et al. 2015

Acta Pharmacol Sin

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“…In this situation, we should isolate and collect tumor cells, for example, by flow cytometry [52]. Besides, due to the suspended trait of the lymphoma cell, we should develop adequate methods to immobilize them for living-cell AFM imaging, for example, micro well array chip [53] and thin film having small pores [54]. Investigating the behavior of living tumor cells from patients will enable us to detect and monitor the physiological properties of living tumor cells (e.g., the cellular changes after the stimulation of drugs), bringing novel information that is closer to the real cellular activities.…”

Section: Force Spectroscopy Of Molecular Interactions On Tumor Cells mentioning

confidence: 99%

Investigating the Molecular Specific Interactions on Cell Surface Using Atomic Force Microscopy

Micro‐ and Nanomanipulation Tools

et al. 2015

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Cancer is the leading cause of death in economically developed countries and the second leading cause of death in developing countries [1]. The new cancer cases will increase from 12.7 million in 2008 to 22.2 million by 2030, while the cancer-related deaths will increase from 7.6 million in 2008 to 13.2 million by 2030 [2]. Carcinogenesis and tumor progression are complex and progressive processes that are associated with numerous genetic and epigenetic alterations [3]. Our growing understanding of tumor biology and genomics paves the way to the development of new therapy approaches, and marked progress has been achieved in overcoming treatment resistance through precision medicine and immunotherapy [4]. However, because of the fact that the exact reason why a cell becomes cancerous is unknown (the only one cancer whose cause is clear is cervical cancer), the current cancer treatments cannot prevent the recurrence of cancers and the age-adjusted mortality rate for cancer is about the same in the twenty-first century as it was 50 years ago [5].Lymphomas, solid tumors of the immune system [6], account for 4%-5% of all cancers [7]. Hodgkin's lymphoma accounts for about 10% of all lymphomas and the remaining 90% are referred to as non-Hodgkin lymphoma (NHL) [6]. NHL can be divided into many subtypes according to the combination of morphology, immunophenotype, genetic, molecular, and clinical features of the tumors [8]. Approximately, 85% of NHL in adults arises from B cells [9], and the rest are T-cell origin [10]. Follicular lymphoma and diffuse large B-cell lymphoma are the two most common B-cell NHLs, comprising 60% of new B-cell NHL diagnoses each year in North America [11]. In 1997, US Food and Drug Administration (FDA) approved rituximab (an anti-CD20 monoclonal antibody (mAb)) for treating B-cell NHLs. CD20 is 297 amino acids long with a molecule weight of about 33 kDa [12]. The exact biological function of CD20 is currently unknown [13], partly because it has no known natural ligand and CD20 knockout mice display an almost normal phenotype [14]. Many of the functions of CD20 have been determined using artificial ligands (antibody) [15]. In vitro experiments proposed that CD20

“…In SMFS mode, AFM can be used to measure affinities, distributions, and unfolding dynamics of membrane proteins. The wide applicability of AFM in biology yields considerable knowledge with regard to cellular activities [70][71][72][73][74], considerably promoting the progress of nanobiotechnology [22]. Although SMFS has been an important way to measure biophysical properties of membrane proteins, several challenges remain.…”

Section: Challenge and Outlookmentioning

confidence: 99%

Progress in measuring biophysical properties of membrane proteins with AFM single-molecule force spectroscopy

et al. 2014

Chin. Sci. Bull.

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Membrane proteins are crucial in cell physiological activities and are the targets for most drugs. Thus, investigating the behaviors of membrane proteins not only provide deeper insights into cell function, but also help disease treatment and drug development. Atomic force microscopy is a unique tool for investigating the structure of membrane proteins. It can both image the morphology of single native membrane proteins with high resolution and, via single-molecule force spectroscopy (SMFS), directly measure their biophysical properties during molecular physiological activities such as ligand binding and protein unfolding. In the context of molecular biomechanics, SMFS has been successfully used to understand the structure and function of membrane proteins, complementing the static three-dimensional structures of proteins obtained by X-ray crystallography. Here, based on the authors' antigen-antibody binding force measurements in clinical tumor cells, the principle and method of SMFS is discussed, the progress in using SMFS to characterize membrane proteins is summarized, and challenges for SMFS are presented.