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Deng H, Wang Y, Yin Y, Shu J, Zhang J, Shu X, Wu F, He J. Effects of matrix viscoelasticity on cell-matrix interaction, actin cytoskeleton organization, and apoptosis of osteosarcoma MG-63 cells. J Mater Chem B 2023; 12:222-232. [PMID: 38079114 DOI: 10.1039/d3tb02001k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
Many recent reports have shown the effects of viscoelasticity of the extracellular matrix on the spreading, migration, proliferation, survival and cell-matrix interaction of mesenchymal stem cells and normal cells. However, the effect of matrix viscoelasticity on the behavior of tumor cells is still in the state of preliminary exploration. To this aim, we prepared a viscoelastic hydrogel matrix with a storage modulus of about 2 kPa and a loss modulus adjustable from 0 to 600 Pa, through adding linear alginate and regulating the compactness of a polyacrylamide covalent network. Overall, the addition of viscous components inhibited the apoptosis of osteosarcoma MG-63 cells, while it promoted their spreading and proliferation and in particular led to a well-developed cytoskeleton organization. However, with the increase of the viscous fraction, this trend was reversed, and the apoptosis of MG-63 cells gradually increased with gradually decreased spreading and proliferation, accompanied by a surprising manner change of the cytoskeleton from fusiform cells dominated by focal adhesion to dendritic cells dominated by pseudopodia. Besides the upregulation of MAPK, Ras, Rap1 and PI3K-Akt pathways commonly involved in mechanotransduction, the upregulation of the Wnt pathway and inhibited endoplasmic reticulum stress-mediated apoptosis were observed for the viscous matrix with a low loss modulus. The high viscosity matrix showed additional involvement of Hippo and NF-kappa B signaling pathways related to the cell-matrix interaction, with downregulation of the endoplasmic reticulum stress pathway and upregulation related to mitochondrial organization. Our study would provide insight into the effect of viscosity on fundamental behaviors of tumor cells and might have important implications in designing antitumor materials.
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Affiliation(s)
- Huan Deng
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, 610064, P. R. China.
| | - Yao Wang
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, 610064, P. R. China.
| | - Yue Yin
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, 610064, P. R. China.
| | - Jun Shu
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, 610064, P. R. China.
| | - Junwei Zhang
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, 610064, P. R. China.
| | - Xuedong Shu
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, 610064, P. R. China.
| | - Fang Wu
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, 610064, P. R. China.
| | - Jing He
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, 610064, P. R. China.
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Deng H, Shu X, Wang Y, Zhang J, Yin Y, Wu F, He J. Matrix Stiffness Regulated Endoplasmic Reticulum Stress-mediated Apoptosis of Osteosarcoma Cell through Ras Signal Cascades. Cell Biochem Biophys 2023; 81:839-850. [PMID: 37789235 DOI: 10.1007/s12013-023-01184-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/20/2023] [Indexed: 10/05/2023]
Abstract
The modulating effects of matrix stiffness on spreading and apoptosis of tumor cells have been well recognized. Nevertheless, the detail road map leading to the apoptosis and the underlying mechanisms governing the cell apoptosis have remained to be elucidated. To this aim, we provided a tunable elastic hydrogel matrix that promoted cell adhesion by modifying the surface of polyacrylamide with polydopamine, with stiffness value of 1, 10, 30, and 250 kPa, respectively. While the cell spreading increased and the apoptosis decreased with the matrix stiffness, such modulating effect of matrix on cell spreading exhibited different time evolvement behaviors as a function of stiffness, which likely led to surprisingly similar apoptosis rates for the 30 kPa and 250 kPa samples. Matrix stiffness mediated the spreading and apoptosis of MG-63 cells by regulating cell adhesion to matrix and in particular cytoskeletal organization, which was dependent on Ras, Rap1 and PI3K-Akt signaling pathways and finally led to the apoptosis of cancer cells dominated by endoplasmic reticulum stress pathway. Our results provided an insight into the regulation of tumor cell fate by the mechanical clues of ECM, which would have implication for future cancer research and the design of novel anticancer materials.
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Affiliation(s)
- Huan Deng
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, 610064, PR China
| | - Xuedong Shu
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, 610064, PR China
| | - Yao Wang
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, 610064, PR China
| | - Junwei Zhang
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, 610064, PR China
| | - Yue Yin
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, 610064, PR China
| | - Fang Wu
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, 610064, PR China
| | - Jing He
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, 610064, PR China.
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3
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Silver BB, Zhang SX, Rabie EM, Nelson CM. Substratum stiffness tunes membrane voltage in mammary epithelial cells. J Cell Sci 2021; 134:jcs256313. [PMID: 34313313 PMCID: PMC8310660 DOI: 10.1242/jcs.256313] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 06/02/2021] [Indexed: 11/20/2022] Open
Abstract
Membrane voltage (Vm) plays a critical role in the regulation of several cellular behaviors, including proliferation, apoptosis and phenotypic plasticity. Many of these behaviors are affected by the stiffness of the underlying extracellular matrix, but the connections between Vm and the mechanical properties of the microenvironment are unclear. Here, we investigated the relationship between matrix stiffness and Vm by culturing mammary epithelial cells on synthetic substrata, the stiffnesses of which mimicked those of the normal mammary gland and breast tumors. Although proliferation is associated with depolarization, we surprisingly observed that cells are hyperpolarized when cultured on stiff substrata, a microenvironmental condition that enhances proliferation. Accordingly, we found that Vm becomes depolarized as stiffness decreases, in a manner dependent on intracellular Ca2+. Furthermore, inhibiting Ca2+-gated Cl- currents attenuates the effects of substratum stiffness on Vm. Specifically, we uncovered a role for cystic fibrosis transmembrane conductance regulator (CFTR) in the regulation of Vm by substratum stiffness. Taken together, these results suggest a novel role for CFTR and membrane voltage in the response of mammary epithelial cells to their mechanical microenvironment.
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Affiliation(s)
- Brian B. Silver
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Sherry X. Zhang
- Department of Chemical & Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Emann M. Rabie
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
- Graduate School of Biomedical Sciences, Rutgers Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA
| | - Celeste M. Nelson
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
- Department of Chemical & Biological Engineering, Princeton University, Princeton, NJ 08544, USA
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Yiu AJ, Ibeh CL, Roy SK, Bandyopadhyay BC. Melamine induces Ca 2+-sensing receptor activation and elicits apoptosis in proximal tubular cells. Am J Physiol Cell Physiol 2017; 313:C27-C41. [PMID: 28381520 DOI: 10.1152/ajpcell.00225.2016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 03/29/2017] [Accepted: 03/30/2017] [Indexed: 01/06/2023]
Abstract
Melamine causes renal tubular cell injury through inflammation, fibrosis, and apoptosis. Although melamine affects the rise in intracellular Ca2+ concentration ([Ca2+]i), reactive oxygen species (ROS) production, and proapoptotic pathway activation, the mechanism of upstream Ca2+ signaling is unknown. Because melamine has some structural similarities with l-amino acids, which endogenously activate Ca2+-sensing receptors (CSR), we examined the effect of melamine on CSR-induced Ca2+ signaling and apoptotic cell death. We show here that melamine activates CSR, causing a sustained Ca2+ entry in the renal epithelial cell line, LLC-PK1. Moreover, such CSR stimulation resulted in a rise in [Ca2+]i, leading to enhanced ROS production. Furthermore, melamine-induced elevated [Ca2+]i and ROS production caused a dose-dependent increase in apoptotic (by DAPI staining, DNA laddering, and annexin V assay) and necrotic (propidium iodide staining) cell death. Upon examining the downstream mechanism, we found that transforming growth factor β1 (TGF-β1), which increases extracellular matrix genes and proapoptotic signaling, was also upregulated at lower doses of melamine, which could be due to an early event inducing apoptosis. Additionally, cells exposed to melamine displayed a rise in pERK activation and lactate dehydrogenase release resulting in cytotoxicity. These results offer a novel insight into the molecular mechanisms by which melamine exerts its effect on CSR, causing a sustained elevation of [Ca2+]i, leading to ROS generation, fibronectin production, proapoptotic pathway activation, and renal cell damage. Together, these results thus suggest that melamine-induced apoptosis and/or necrosis may subsequently result in acute kidney injury and promote kidney stone formation.
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Affiliation(s)
- Allen J Yiu
- Calcium Signaling Laboratory, Research Service, Veterans Affairs Medical Center, Washington, District of Columbia.,Department of Pharmacology and Physiology, School of Medicine, George Washington University, Washington, District of Columbia; and
| | - Cliff-Lawrence Ibeh
- Calcium Signaling Laboratory, Research Service, Veterans Affairs Medical Center, Washington, District of Columbia
| | - Sanjit K Roy
- Calcium Signaling Laboratory, Research Service, Veterans Affairs Medical Center, Washington, District of Columbia
| | - Bidhan C Bandyopadhyay
- Calcium Signaling Laboratory, Research Service, Veterans Affairs Medical Center, Washington, District of Columbia; .,Department of Pharmacology and Physiology, School of Medicine, George Washington University, Washington, District of Columbia; and.,Department of Pharmacology and Physiology, Georgetown University, Washington, District of Columbia
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Lin HH, Lin HK, Lin IH, Chiou YW, Chen HW, Liu CY, Harn HIC, Chiu WT, Wang YK, Shen MR, Tang MJ. Mechanical phenotype of cancer cells: cell softening and loss of stiffness sensing. Oncotarget 2016; 6:20946-58. [PMID: 26189182 PMCID: PMC4673241 DOI: 10.18632/oncotarget.4173] [Citation(s) in RCA: 110] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 05/02/2015] [Indexed: 01/06/2023] Open
Abstract
The stiffness sensing ability is required to respond to the stiffness of the matrix. Here we determined whether normal cells and cancer cells display distinct mechanical phenotypes. Cancer cells were softer than their normal counterparts, regardless of the type of cancer (breast, bladder, cervix, pancreas, or Ha-RasV12-transformed cells). When cultured on matrices of varying stiffness, low stiffness decreased proliferation in normal cells, while cancer cells and transformed cells lost this response. Thus, cancer cells undergo a change in their mechanical phenotype that includes cell softening and loss of stiffness sensing. Caveolin-1, which is suppressed in many tumor cells and in oncogene-transformed cells, regulates the mechanical phenotype. Caveolin-1-upregulated RhoA activity and Y397FAK phosphorylation directed actin cap formation, which was positively correlated with cell elasticity and stiffness sensing in fibroblasts. Ha-RasV12-induced transformation and changes in the mechanical phenotypes were reversed by re-expression of caveolin-1 and mimicked by the suppression of caveolin-1 in normal fibroblasts. This is the first study to describe this novel role for caveolin-1, linking mechanical phenotype to cell transformation. Furthermore, mechanical characteristics may serve as biomarkers for cell transformation.
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Affiliation(s)
- Hsi-Hui Lin
- Department of Physiology, National Cheng Kung University, Tainan, Taiwan
| | - Hsiu-Kuan Lin
- Institute of Basic Medical Sciences, National Cheng Kung University, Tainan, Taiwan
| | - I-Hsuan Lin
- Department of Physiology, National Cheng Kung University, Tainan, Taiwan
| | - Yu-Wei Chiou
- Department of Biomedical Engineering, National Cheng Kung University, Tainan, Taiwan
| | - Horn-Wei Chen
- Department of Physiology, National Cheng Kung University, Tainan, Taiwan
| | - Ching-Yi Liu
- Institute of Basic Medical Sciences, National Cheng Kung University, Tainan, Taiwan
| | - Hans I-Chen Harn
- Institute of Basic Medical Sciences, National Cheng Kung University, Tainan, Taiwan
| | - Wen-Tai Chiu
- Department of Biomedical Engineering, National Cheng Kung University, Tainan, Taiwan
| | - Yang-Kao Wang
- Department of Cell Biology and Anatomy, National Cheng Kung University, Tainan, Taiwan
| | - Meng-Ru Shen
- Department of Pharmacology, National Cheng Kung University, Tainan, Taiwan
| | - Ming-Jer Tang
- Department of Physiology, National Cheng Kung University, Tainan, Taiwan.,Institute of Basic Medical Sciences, National Cheng Kung University, Tainan, Taiwan
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Hayakawa K, Tatsumi H, Sokabe M. Mechano-sensing by actin filaments and focal adhesion proteins. Commun Integr Biol 2013; 5:572-7. [PMID: 23336027 PMCID: PMC3541324 DOI: 10.4161/cib.21891] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Mechanosensitive ion channels have long been the only established molecular class of cell mechanosensors with known molecular entities. However, recent advances in the state-of-the-art techniques, including single-molecule manipulation and imaging, have enabled an investigation of non-channel type cell mechanosensors and the underlying biophysical mechanisms of their activation. To date, two focal adhesion proteins, talin and p130Cas, have been postulated to act as putative mechanosensors, acting through mechano-induced unfolding of their particular soft domain(s) susceptible to phosphorylation. More recently, the actin filament has been demonstrated to act as a mechanosensor in the presence of the soluble actin-severing protein, cofilin. The cofilin severing activity negatively depends on the tension in the actin filament through tension-dependent binding/unbinding of cofilin to/from the actin filament. As a result, relaxed actin filaments are severed, while tensed ones are either not severed or severed after a long delay. Here we review the latest progress in the mechanosensing by non-channel type proteins and discuss the possible physiological roles of the mechanosensing performed by actin filaments in the course of cell migration.
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Affiliation(s)
- Kimihide Hayakawa
- FIRST Research Center for Innovative Nanobiodevice; Nagoya University; Nagoya, Japan
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Lo CJ, Lo EJ. Angiotensin II inhibits interleukin-6 mRNA expression of LPS-stimulated macrophages through down-regulating calcium signaling. J Surg Res 2012; 181:287-92. [PMID: 22884451 DOI: 10.1016/j.jss.2012.07.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2010] [Revised: 06/07/2012] [Accepted: 07/02/2012] [Indexed: 11/25/2022]
Abstract
BACKGROUND The renin-angiotensin system plays a key role in the regulation of blood pressure following hemorrhage and shock. Recent studies also suggest renin-angiotensin system regulates inflammatory mediator production although the amechanism is largely unknown. This purpose of the study was to examine the effect of angiotensin II on macrophage (MØ) IL-6 messenger RNA (mRNA) expression induced by lipopolysaccharide (LPS) and on the alterations in the calcium influx. METHODS J774A.1 cells, a mouse MØ cell line, were exposed to E. coli LPS (1 or 10 μg/ml) in the presence of angiotensin II (10 nM to 1 μM). IL-6 mRNA expression was determined by the reverse transcription polymerase chain reaction technique. IL-6 protein production was measured by ELISA. To examine the involvement of calcium signaling in IL-6 mRNA expression, MØ were exposed to various calcium agonists and antagonists in the presence of LPS stimulation. Changes of intracellular [Ca(2+)] by LPS stimulation and angiotensin II treatment were determined by a fura-2 fluorescence ratio method. RESULTS LPS stimulation increased MØ IL-6 mRNA expression, which was inhibited by Angiotensin II in a dose-dependent fashion. Both thapsigargin and A23187 augmented the IL-6 mRNA levels induced by LPS stimulation, but only thapsigargin was able to induce IL-6 mRNA directly. TMB-8 but not verapamil inhibited LPS-stimulated MØ IL-6 mRNA. Finally, angiotensin II significantly altered the changes in intracellular [Ca(2+)] levels induced by LPS stimulation by reducing both the peak and slope of calcium spikes. CONCLUSIONS Our data show that calcium signaling is closely related to IL-6 mRNA expression. Angiotensin II inhibits IL-6 mRNA expression of LPS-stimulated MØ. The inhibitory effects of angiotensin II appear, at least in part, to be mediated through down regulating calcium dependent pathways.
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Affiliation(s)
- Chong-Jeh Lo
- Division of Trauma, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan.
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Ischemia-induced apoptosis of intestinal epithelial cells correlates with altered integrin distribution and disassembly of F-actin triggered by calcium overload. J Biomed Biotechnol 2012; 2012:617539. [PMID: 22701305 PMCID: PMC3369571 DOI: 10.1155/2012/617539] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Accepted: 03/23/2012] [Indexed: 12/18/2022] Open
Abstract
The present study examined intestinal epithelial cell (IEC) integrin distribution and disassembly of actin cytoskeleton in response to ischemia-anoxia. Protective effects of calcium channel blocker(CCB) were further examined to explore underlying mechanisms of cellular injury. Materials and Methods. Primary cultures of rat IECs and an in vitro model of ischemia/anoxia were established. IECs were exposed to ischemia/anoxia in the presence and absence of verapamil. The extent of exfoliation was determined using light microscopy while apoptosis rate was measured using flow cytometry. Changes in intracellular calcium, the distribution of integrins and the morphology of F-actin were assessed by confocal microscopy. Results. Detachment and apoptosis of IECs increased following ischemia/anoxia-induced injury. Treatment with verapamil inhibited the detachment and apoptosis. Under control conditions, the strongest fluorescent staining for integrins appeared on the basal surface of IECs while this re-distributed to the apical membrane in response to ischemic injury. Depolymerization of F-actin was also observed in the injured cells. Verapamil attenuated both changes of integrins and F-actin. Conclusions. Redistribution of integrins and disruption of F-actin under ischemia/anoxia injury is associated with IEC detachment and increased apoptosis. These events appeared to be triggered by an increase in Ca2+i suggesting a potential use for CCB in prevention and treatment of intestinal injury.
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Cai BZ, Meng FY, Zhu SL, Zhao J, Liu JQ, Liu CJ, Chen N, Ye ML, Li ZY, Ai J, Lu YJ, Yang BF. Arsenic trioxide induces the apoptosis in bone marrow mesenchymal stem cells by intracellular calcium signal and caspase-3 pathways. Toxicol Lett 2010; 193:173-8. [PMID: 20079407 DOI: 10.1016/j.toxlet.2010.01.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2009] [Revised: 12/08/2009] [Accepted: 01/06/2010] [Indexed: 01/09/2023]
Abstract
It was previously reported that excessive arsenic trioxide would produce cardiovascular toxicity. Bone marrow mesenchymal stem cells (BMSCs) have been shown to play a supporting role in cardiovascular functions. The increasing apoptosis of BMSCs commonly would promote the development of cardiovascular diseases. Thus we hypothesize that arsenic trioxide caused apoptosis in BMSCs, which provided a better understanding of arsenic toxicity in hearts. The present study was designed to investigate the proapoptotic effects of arsenic trioxide on BMSCs and explore the mechanism underlying arsenic trioxide-induced BMSCs apoptosis. We demonstrate that arsenic trioxide significantly inhibited survival ratios of BMSCs in a concentration-dependent and time-dependent manner. The Annexin V/PI staining and terminal deoxynucleotidyl transferasemediated dUTP nick-end labelling (TUNEL) assay also showed that arsenic trioxide markedly induced the apoptosis of BMSCs. The caspase-3 activity was obviously enhanced in the presence of arsenic trioxide in a concentration-dependent manner in BMSCs. Additionally, arsenic trioxide caused the increase of intracellular free calcium ([Ca(2+)](i)) in rat BMSCs. BAPTA pretreatment may attenuate the apoptosis of BMSCs induced by arsenic trioxide. Taken together, arsenic trioxide could inhibit the proliferation and induce the apoptosis of BMSCs by modulating intracellular [Ca(2+)](i), and activating the caspase-3 activity.
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Affiliation(s)
- Ben-Zhi Cai
- Department of Pharmacology, Harbin Medical University, Baojian Road 157, Harbin 150081, China
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Wei WC, Lin HH, Shen MR, Tang MJ. Mechanosensing machinery for cells under low substratum rigidity. Am J Physiol Cell Physiol 2008; 295:C1579-89. [PMID: 18923058 DOI: 10.1152/ajpcell.00223.2008] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mechanical stimuli are essential during development and tumorigenesis. However, how cells sense their physical environment under low rigidity is still unknown. Here we show that low rigidity of collagen gel downregulates beta(1)-integrin activation, clustering, and focal adhesion kinase (FAK) Y397 phosphorylation, which is mediated by delayed raft formation. Moreover, overexpression of autoclustered beta(1)-integrin (V737N), but not constitutively active beta(1)-integrin (G429N), rescues FAKY397 phosphorylation level suppressed by low substratum rigidity. Using fluorescence resonance energy transfer to assess beta(1)-integrin clustering, we have found that substratum rigidity between 58 and 386 Pa triggers beta(1)-integrin clustering in a dose-dependent manner, which is highly dependent on actin filaments but not microtubules. Furthermore, augmentation of beta(1)-integrin clustering enhances the interaction between beta(1)-integrin, FAK, and talin. Our results indicate that contact with collagen fibrils is not sufficient for integrin activation. However, substratum rigidity is required for integrin clustering and activation. Together, our findings provide new insight into the mechanosensing machinery and the mode of action for epithelial cells in response to their physical environment under low rigidity.
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Affiliation(s)
- Wei-Chun Wei
- Department of Physiology, National Cheng Kung University, Medical College, Tainan 701, Taiwan
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Chiu WT, Tang MJ, Jao HC, Shen MR. Soft substrate up-regulates the interaction of STIM1 with store-operated Ca2+ channels that lead to normal epithelial cell apoptosis. Mol Biol Cell 2008; 19:2220-30. [PMID: 18337467 PMCID: PMC2366837 DOI: 10.1091/mbc.e07-11-1170] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2007] [Revised: 02/12/2008] [Accepted: 02/29/2008] [Indexed: 11/11/2022] Open
Abstract
We have demonstrated that soft substrate induced apoptosis in polarized cells, but not in transformed cells by disturbance of Ca(2+) homeostasis. This study aims to further investigate the regulatory mechanisms underlying the disruption of Ca(2+)-signaling integrity in soft substrate-induced epithelial apoptosis. Soft substrate up-regulated the store-operated Ca(2+) (SOC) entry across the plasma membrane of normal cervical epithelial cells, which resulted in increased cytosolic Ca(2+) levels. Concomitantly, soft substrate induced the aggregation and translocation of stromal interacting molecule 1 (STIM1) toward the cell periphery to colocalize with Orai1, an essential pore subunit of SOC channel, detected by fluorescence resonance energy transfer approach and confocal image analyses. The disturbed Ca(2+) homeostasis resulted in the activation of mu-calpain, which cleaved alpha-spectrin, induced actin disorganization, and caused apoptosis. In contrast, soft substrate did not disturb Ca(2+) homeostasis or induce apoptosis in cervical cancer cells. Chelating extracellular Ca(2+) by EGTA and down-regulated SOC entry by small interfering RNA targeting STIM1 or inhibitors targeting Ca(2+)-binding site of calpain significantly inhibited soft substrate-induced activation of mu-calpain and epithelial cell apoptosis. Thus, soft substrate up-regulates the interaction of STIM1 with SOC channels, which results in the activation of mu-calpain and subsequently induces normal epithelial cell apoptosis.
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Affiliation(s)
| | - Ming-Jer Tang
- Department of Physiology
- Center for Gene Regulation and Signal Transduction Research, and
| | | | - Meng-Ru Shen
- Center for Gene Regulation and Signal Transduction Research, and
- Departments of Pharmacology and
- Obstetrics and Gynecology, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan
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