Activation of stress-related signalling pathway in human cells upon SiO2 nanoparticles exposure as an early indicator of cytotoxicity

Mohamed, Bashir M.; Verma, Navin Kumar; Prina-Mello, Adriele; Williams, Yvonne; Davies, Anthony M.; Bakos, Gábor; Tormey, Laragh; Edwards, C.C.; Hanrahan, John P.; Salvati, Anna; Lynch, Iseult; Dawson, Kenneth A.; Kelleher, Dermot; Volkov, Yuri

doi:10.1186/1477-3155-9-29

Cited by 79 publications

(76 citation statements)

References 74 publications

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“…Adhesion of cells on anti-integrin antibody or fibronectin coated surfaces was detected and subsequently quantified using a cell based high content analysis (HCA) system. The assay operates on the principle of fully automated fluorescent microscopy described previously (30)(31)(32) and allows multiplexing of key reporter parameters including cell-adhesion. Untreated or PBOX-15 pre-treated cells were added to fibronectin, anti-α4-, β1-, or β2-integrin antibody coated 24-well or 96-well plates (Nunc, Roskilide, Denmark) at a density of 2x10 5 or 1x10 4 cells/well respectively.…”

Section: Methodsmentioning

confidence: 99%

The microtubule targeting agent PBOX-15 inhibits integrin-mediated cell adhesion and induces apoptosis in acute lymphoblastic leukaemia cells

Lysaght

Verma

Maginn

et al. 2012

International Journal of Oncology

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Abstract. Although recent decades have seen an improved cure rate for newly diagnosed paediatric acute lymphoplastic leukaemia (ALL), the treatment options for adult ALL, T-cell ALL (T-ALL) and relapsed disease remain poor. We have developed a novel series of pyrrolo-1,5-benzoxazepine (PBOX) compounds and established their anticancer efficacy in a variety of human tumour cell types. Here, we demonstrate that PBOX-15 inhibits cell growth, and induces G2/M cell cycle arrest and apoptosis in both T-ALL and B-cell ALL (B-ALL) cells. In addition, prior to PBOX-15-induced apoptosis, PBOX-15 decreases ALL cell adhesion, spreading and migration. Concurrently, PBOX-15 differentially down-regulates β1-, β2-and α4-integrin expression in ALL cells and significantly decreases integrin-mediated cell attachment. PBOX-15 interferes with the lateral mobility and clustering of integrins in both B-ALL and T-ALL cells. These data suggest that PBOX-15 is not only effective in inducing apoptosis in ALL cells, but also has the potential to disrupt integrin-mediated adhesion of malignant lymphocytes, which represents a novel avenue for regulating leukaemic cell homing and migration. IntroductionAcute lymphoblastic leukaemia (ALL) refers to a group of malignancies arising from lymphoid progenitors that may be of B-or T-cell lineage (B-ALL or T-ALL), resulting in proliferation and expansion of lymphoid blasts in bone marrow, blood and other organs. ALL has an overall incidence of 1-1.5 per 100,000 individuals and exhibits a bimodal age distribution with an early peak between ages 2-5 years (4-5 per 100,000 individuals, accounting for 80% of all childhood leukaemia), followed by a second peak after the age of 50 years (1). The treatment of ALL involves complex therapeutic programmes using intensive combination chemotherapy in dose-and timespecific sequences resulting in survival rates greater than 80% in children (2). However, there is a need for novel treatment options as only 30-40% of adults achieve long-term diseasefree survival and both childhood T-ALL and relapsed ALL are associated with poor clinical outcome (3,4).Microtubule targeting agents (MTAs) have been shown to be effective against ALL cells and vincristine is a key component of induction, consolidation and maintenance treatment protocols (3). We have previously described a novel MTA, pyrrolo-1,5-benzoxazepine-15 (PBOX-15), which exhibits anticancer activity against a variety of human tumour cell types, including those derived from both solid and haematological malignancies (5-10). Importantly, PBOX-15 and other related PBOX compounds display minimal toxicity against normal human blood and bone marrow cells, and are well tolerated by both tumour-bearing and healthy mice (7,11).MTA's interference with tubulin dynamics during mitotic spindle formation is well established; however, due to the critical role of microtubules in cell motility and homeostasis, the activity of MTAs may extend beyond inhibition of cytokinesis and subsequent induction of apoptosis. For example, we have...

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Section: Methodsmentioning

confidence: 99%

The microtubule targeting agent PBOX-15 inhibits integrin-mediated cell adhesion and induces apoptosis in acute lymphoblastic leukaemia cells

Lysaght

Verma

Maginn

et al. 2012

International Journal of Oncology

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“…SiO 2 NPs may exist in many different forms, including different crystallinity, morphology, and pore structure, with each form exhibiting unique characteristics [31][32][33]. Although several in vitro studies using SiO 2 NPs have been performed to show either cytotoxicity [34][35][36] or no effect on viability in vitro [34,37,38], there is limited information regarding SiO 2 NPs interference with plate-based assays. For example, it is known that ViaLight substrate (fluorescent ATP) caused precipitation of 15 nm SiO 2 NP resulting in a cloudy appearance of NP, but without ultimately affecting luminescence signal [22], and SiO 2 NPs (15 nm) caused precipitation of LDH resulting in high absorbance values and false-positive results [22]; astrocytes treated with mesoporous silica NPs (SiO 2 NP) show decreased MTT signal due to SiO 2 NP-mediated formazan exocytosis as opposed to decreased viability [39].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Viability and Proliferation Profiles on Macrophages Treated with Silica Nanoparticles In Vitro via Plate-Based, Flow Cytometry, and Coulter Counter Assays

Bancos

Tsai

Hackley

et al. 2012

ISRN Nanotechnology

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Nanoparticles (NPs) are known to interfere with many high-throughput cell viability and cell proliferation assays, which complicates the assessment of their potential toxic effects. The aim of this study was to compare viability and proliferation results for colloidal silica (SiO 2 NP; 7 nm) in the RAW 264.7 mouse macrophage cell line using three different techniques: plate-based assays, flow cytometry analysis, and Coulter counter assays. Our data indicate that CellTiter-Blue, XTT, and CyQuant plate-based assays show increased values over control at low SiO 2 NPs concentrations (0.001-0.01 g/L). SiO 2 NPs show little-to-no interference with flow cytometry and Coulter counter assays, which not only were more reliable in determining cell viability and proliferation at low concentrations in vitro, but also identified changes in cell granularity and size that were not captured by the plate-based assays. At high SiO 2 NP concentrations (1 g/L) all techniques indicated cytotoxicity. In conclusion, flow cytometry and Coulter counter identified new cellular features, and flow cytometry offered more flexibility in analyzing the viability and proliferation profile of SiO 2 NP-treated RAW 264.7 cells.

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“…Before the start of the experiments, the nuclei were stained with Hoechst (1:1000 from stock of 1 mg/mL) for 5 minutes. After washing the cells with medium, endothelial monolayers (normal or supplemented with tumor necrosis factor-α [TNF-α] at 10 ng/mL for 12 hours) were exposed to QD2.7, QD4.7, or NP50 suspended in PBS under low, medium, and high SS rates (0.05, 0.10, and 0.50 Pa, respectively) for 20 minutes using 41 …”

Section: Evaluation Of Nanoparticle Uptake By Human Umbilical Vein Enmentioning

confidence: 99%

Multifactorial determinants that govern nanoparticle uptake by human endothelial cells under flow

Samuel¹,

Jain²,

O'Dowd³

et al. 2012

IJN

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Vascular endothelium is a potential target for therapeutic intervention in diverse pathological processes, including inflammation, atherosclerosis, and thrombosis. By virtue of their intravascular topography, endothelial cells are exposed to dynamically changing mechanical forces that are generated by blood flow. In the present study, we investigated the interactions of negatively charged 2.7 nm and 4.7 nm CdTe quantum dots and 50 nm silica particles with cultured endothelial cells under regulated shear stress (SS) conditions. Cultured cells within the engineered microfluidic channels were exposed to nanoparticles under static condition or under low, medium, and high SS rates (0.05, 0.1, and 0.5 Pa, respectively). Vascular inflammation and associated endothelial damage were simulated by treatment with tumor necrosis factor-α (TNF-α) or by compromising the cell membrane with the use of low Triton X-100 concentration. Our results demonstrate that SS is critical for nanoparticle uptake by endothelial cells. Maximal uptake was registered at the SS rate of 0.05 Pa. By contrast, endothelial exposure to mild detergents or TNF-α treatment had no significant effect on nanoparticle uptake. Atomic force microscopy demonstrated the increased formation of actin-based cytoskeletal structures, including stress fibers and membrane ruffles, which have been associated with nanoparticle endocytosis. In conclusion, the combinatorial effects of SS rates, vascular endothelial conditions, and nanoparticle physical and chemical properties must be taken into account for the successful design of nanoparticle-drug conjugates intended for parenteral delivery. Keywords: endothelium, shear stress, quantum dots, membrane ruffling, stress fibers, atomic force microscopy, microfluidics Nanoparticle (NP) technologies are significantly affecting the development of both therapeutic and diagnostic agents. Although enormous progress in the field of nanotechnology has been achieved, basic discoveries have not yet translated into effective targeted therapies. NPs can potentially improve the pharmacokinetics and pharmacodynamics of drugs; however, the complexity of in vivo systems imposes multiple barriers that severely inhibit efficiency, which must be overcome to fully exploit the theoretical potential of NPs. Endothelial cells (ECs) that line the interior of the entire vascular system represent a major barrier for therapeutic agents traveling from the bloodstream to the target tissues. Recent studies have focused on targeting the endothelium with NPs as therapeutic agents for a variety of pathological conditions in the vascular system because of the large population of ECs and their proximity to the blood flow.ECs in vivo are exposed to a variety of hemodynamic forces that are created by blood flow and by the pulse wave dictated by the cardiac cycle. Shear stress (SS) is the dragging mechanical force that acts at the interface between flowing blood and Dovepress submit your manuscript | www.dovepress.com the vessel wall. ECs recognize SS a...

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Activation of stress-related signalling pathway in human cells upon SiO2 nanoparticles exposure as an early indicator of cytotoxicity

Cited by 79 publications

References 74 publications

The microtubule targeting agent PBOX-15 inhibits integrin-mediated cell adhesion and induces apoptosis in acute lymphoblastic leukaemia cells

The microtubule targeting agent PBOX-15 inhibits integrin-mediated cell adhesion and induces apoptosis in acute lymphoblastic leukaemia cells

Evaluation of Viability and Proliferation Profiles on Macrophages Treated with Silica Nanoparticles In Vitro via Plate-Based, Flow Cytometry, and Coulter Counter Assays

Multifactorial determinants that govern nanoparticle uptake by human endothelial cells under flow

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