Diamond, graphite, and graphene oxide nanoparticles decrease migration and invasiveness in glioblastoma cell lines by impairing extracellular adhesion

Neurodiagnostic and neurotherapeutic potential of graphene nanomaterials

Graphene has emerged as a highly promising nanomaterial for a variety of advanced technologies, including batteries, energy, electronics, and biotechnologies. Its recent contribution to neurotechnology is particularly noteworthy because its superior conductivity, chemical resilience, biocompatibility, thermal stability, and scalable nature make it well-suited for measuring brain activity and plasticity in health and disease. Graphene-mediated compounds are microfabricated in two central methods: chemical processes with natural graphite and chemical vapor deposition of graphene in a film form. They are widely used as biosensors and bioelectronics for neurodiagnostic and neurotherapeutic purposes in several brain disorders, such as Parkinson's disease, stroke, glioma, epilepsy, tinnitus, and Alzheimer's disease. This review provides an overview of studies that have demonstrated the technical advances of graphene nanomaterials in neuroscientific and clinical applications. We also discuss current limitations and future demands in relation to the clinical application of graphene, highlighting its potential technological and clinical significance for treating brain disorders. Our review underscores the potential of graphene nanomaterials as powerful tools for advancing the understanding of the brain and developing new therapeutic strategies.

Dependence of diamond nanoparticle cytotoxicity on physicochemical parameters: comparative studies of glioblastoma, breast cancer, and hepatocellular carcinoma cell lines

Reports on the cytotoxicity of diamond nanoparticles (ND) are ambiguous and depend on the physicochemical properties of the material and the tested cell lines. Thus, the aim of this research was to evaluate the influence of thirteen types of diamond nanoparticles, differing in production method, size, and surface functional groups, on their cytotoxicity against four tumor cell lines (T98G, U-118 MG, MCF-7, and Hep G2) and one non-tumor cell line (HFF-1). In order to understand the dependence of diamond nanoparticles on physicochemical properties, the following parameters were analyzed: viability, cell membrane damage, morphology, and the level of intracellular general ROS and mitochondrial superoxide. The performed analyses revealed that all diamond nanoparticles showed no toxicity to MCF-7, Hep G2, and HFF-1 cells. In contrast, the same nanomaterials were moderately toxic for the glioblastoma T98G and U-118 MG cell lines. In general, the effect of the production method did not influence ND toxicity. Some changes in cell response after treatment with modified nanomaterials were observed, with the presence of carboxyl groups having a more detrimental effect than the presence of other functional groups. Although nanoparticles of different sizes caused similar toxicity, nanomaterials with bigger particles caused a more pronounced effect.

Functional Graphene for Peritumoral Brain Microenvironment Modulation Therapy in Glioblastoma

Peritumoral brain invasion is the main target to cure glioblastoma. Chemoradiotherapy and targeted therapies fail to combat peritumoral relapse. Brain inaccessibility and tumor heterogeneity explain this failure, combined with overlooking the peritumor microenvironment. Reduce graphene oxide (rGO) provides a unique opportunity to modulate the local brain microenvironment. Multimodal graphene impacts are reported on glioblastoma cells in vitro but fail when translated in vivo because of low diffusion. This issue is solved by developing a new rGO formulation involving ultramixing during the functionalization with polyethyleneimine (PEI) leading to the formation of highly water-stable rGO-PEI. Wide mice brain diffusion and biocompatibility are demonstrated. Using an invasive GL261 model, an anti-invasive effect is observed. A major unexpected modification of the peritumoral area is also observed with the neutralization of gliosis. In vitro, mechanistic investigations are performed using primary astrocytes and cytokine array. The result suggests that direct contact of rGO-PEI_UT neutralizes astrogliosis, decreasing several proinflammatory cytokines that would explain a bystander tumor anti-invasive effect. rGO also significantly downregulates several proinvasive/protumoral cytokines at the tumor cell level. The results open the way to a new microenvironment anti-invasive nanotherapy using a new graphene nanomaterial that is optimized for in vivo brain delivery.

Electrostatic polarization fields trigger glioblastoma stem cell differentiation

Over the last few years it has been understood that the interface between living cells and the underlying materials can be a powerful tool to manipulate cell functions. In this study, we explore the hypothesis that the electrical cell/material interface can regulate the differentiation of cancer stem-like cells (CSCs). Electrospun polymer fibres, either polyamide 66 or poly(lactic acid), with embedded graphene nanoplatelets (GnPs), have been fabricated as CSC scaffolds, providing both the 3D microenvironment and a suitable electrical environment favorable for CSCs adhesion, growth and differentiation. We have investigated the impact of these scaffolds on the morphological, immunostaining and electrophysiological properties of CSCs extracted from human glioblastoma multiform (GBM) tumor cell line. Our data provide evidence in favor of the ability of GnP-incorporating scaffolds to promote CSC differentiation to the glial phenotype. Numerical simulations support the hypothesis that the electrical interface promotes the hyperpolarization of the cell membrane potential, thus triggering the CSC differentiation. We propose that the electrical cell/material interface can regulate endogenous bioelectrical cues, through the membrane potential manipulation, resulting in the differentiation of CSCs. Material-induced differentiation of stem cells and particularly of CSCs, can open new horizons in tissue engineering and new approaches to cancer treatment, especially GBM.

Reduced Graphene Oxide Modulates the FAK-Dependent Signaling Pathway in Glioblastoma Multiforme Cells In Vitro

Aggressive invasiveness is a common feature of malignant gliomas, despite their high level of tumor heterogeneity and possible diverse cell origins. Therefore, it is important to explore new therapeutic methods. In this study, we evaluated and compared the effects of graphene (GN) and reduced graphene oxides (rGOs) on a highly invasive and neoplastic cell line, U87. The surface functional groups of the GN and rGO flakes were characterized by X-ray photoelectron spectroscopy. The antitumor activity of these flakes was obtained by using the neutral red assay and their anti-migratory activity was determined using the wound healing assay. Further, we investigated the mRNA and protein expression levels of important cell adhesion molecules involved in migration and invasiveness. The rGO flakes, particularly rGO/ATS and rGO/TUD, were found highly toxic. The migration potential of both U87 and Hs5 cells decreased, especially after rGO/TUD treatment. A post-treatment decrease in mobility and FAK expression was observed in U87 cells treated with rGO/ATS and rGO/TUD flakes. The rGO/TUD treatment also reduced β-catenin expression in U87 cells. Our results suggest that rGO flakes reduce the migration and invasiveness of U87 tumor cells and can, thus, be used as potential antitumor agents.

The Role of Graphene Oxide Nanocarriers in Treating Gliomas

Gliomas are the most common primary malignant tumors of the central nervous system, and their conventional treatment involves maximal safe surgical resection combined with radiotherapy and temozolomide chemotherapy; however, this treatment does not meet the requirements of patients in terms of survival and quality of life. Graphene oxide (GO) has excellent physical and chemical properties and plays an important role in the treatment of gliomas mainly through four applications, viz. direct killing, drug delivery, immunotherapy, and phototherapy. This article reviews research on GO nanocarriers in the treatment of gliomas in recent years and also highlights new ideas for the treatment of these tumors.

Diamond Nanofilm Normalizes Proliferation and Metabolism in Liver Cancer Cells

Purpose

Surgical resection of hepatocellular carcinoma can be associated with recurrence resulting from the degeneration of residual volume of the liver. The objective was to assess the possibility of using a biocompatible nanofilm, made of a colloid of diamond nanoparticles (nfND), to fill the side after tumour resection and optimize its contact with proliferating liver cells, minimizing their cancerous transformation.

Methods

HepG2 and C3A liver cancer cells and HS-5 non-cancer cells were used. An aqueous colloid of diamond nanoparticles, which covered the cell culture plate, was used to create the nanofilm. The roughness of the resulting nanofilm was measured by atomic force microscopy. Mitochondrial activity and cell proliferation were measured by XTT and BrdU assays. Cell morphology and a scratch test were used to evaluate the invasiveness of cells. Flow cytometry determined the number of cells within the cell cycle. Protein expression in was measured by mass spectrometry.

Results

The nfND created a surface with increased roughness and exposed oxygen groups compared with a standard plate. All cell lines were prone to settling on the nanofilm, but cancer cells formed more relaxed clusters. The surface compatibility was dependent on the cell type and decreased in the order C3A >HepG2 >HS-5. The invasion was reduced in cancer lines with the greatest effect on the C3A line, reducing proliferation and increasing the G2/M cell population. Among the proteins with altered expression, membrane and nuclear proteins dominated.

Conclusion

In vitro studies demonstrated the antiproliferative properties of nfND against C3A liver cancer cells. At the same time, the need to personalize potential therapy was indicated due to the differential protein synthetic responses in C3A vs HepG2 cells. We documented that nfND is a source of signals capable of normalizing the expression of many intracellular proteins involved in the transformation to non-cancerous cells.

Recent advances in nano delivery systems for blood-brain barrier (BBB) penetration and targeting of brain tumors

Gliomas constitute about 80% of brain tumors and have a meager two-year survival rate. The treatment options available are very few because of poor prognosis and a lack of targeted nanodelivery systems that can cross the blood-brain barrier (BBB) and the blood-tumor barrier. This short review attempts to clarify the challenges for delivery systems designed to cross the BBB, and provides a brief description of the different types of targeted nanodelivery system that have shown potential for success in delivering drugs to the brain. Further, this review describes the most recent studies that have developed nanoparticles for brain delivery in the past five years. We also provide an insight into the most recent clinical trials designed to assess the efficacy of these nanodelivery systems for glioma.

Tuning protein adsorption on graphene surfaces via laser-induced oxidation

An approach for controlled protein immobilization on laser-induced two-photon (2P) oxidation patterned graphene oxide (GO) surfaces is described. Selected proteins, horseradish peroxidase (HRP) and biotinylated bovine serum albumin (b-BSA) were successfully immobilized on oxidized graphene surfaces, via non-covalent interactions, by immersion of graphene-coated microchips in the protein solution. The effects of laser pulse energy, irradiation time, protein concentration and duration of incubation on the topography of immobilized proteins and consequent defects upon the lattice of graphene were systemically studied by atomic force microscopy (AFM) and Raman spectroscopy. AFM and fluorescence microscopy confirmed the selective aggregation of protein molecules towards the irradiated areas. In addition, the attachment of b-BSA was detected by a reaction with fluorescently labelled avidin-fluorescein isothiocyanate (Av-FITC). In contrast to chemically oxidized graphene, laser-induced oxidation introduces the capability for localization on oxidized areas and tunability of the levels of oxidation, resulting in controlled guidance of proteins by light over graphene surfaces and progressing towards graphene microchips suitable for biomedical applications.

Spray-On Nanocomposite Coatings: Wettability and Conductivity

Nanocomposite coatings, i.e., a combination of nanocompounds, and a polymer matrix together with suitable additives and solvents is a very versatile method for producing multifunctional coatings. Some of the most desired coating properties have a high repellency to liquids (e.g., superhydrophobic and/or superoleophobic) and electrical and thermal conductivities. From a practical perspective, coatings that can be sprayed are very suitable for large-scale production, conformity, and reduced time and cost. Carbon-based, metallic, and ceramic are the three groups of nanocompounds commonly used to formulate spray-on nanocomposite coatings. In this invited feature article, we discuss the applications, advantages, and challenges of using such nanocompounds to produce coatings with good water repellency or/and elevated electrical or/and thermal conductivities. We also discuss the role of additives and solvents briefly in relation to the properties of the coatings. Important spraying parameters, such as stand-off distance and its influence on the final coating properties, will also be examined. Our overall aim is to provide a guideline for the production of practical multifunctional nanocomposites utilizing carbon-based, metallic, or ceramic nanoparticles or nanofibers that covers both aspects of in-air wettability and conductivity under one umbrella.

Effect of Graphene Family Materials on Multiple Myeloma and Non-Hodgkin's Lymphoma Cell Lines

The interest around the graphene family of materials is constantly growing due to their potential application in biomedical fields. The effect of graphene and its derivatives on cells varies amongst studies depending on the cell and tissue type. Since the toxicity against non-adherent cell lines has barely been studied, we investigated the effect of graphene and two different graphene oxides against four multiple myeloma cell lines, namely KMS-12-BM, H929, U226, and MM.1S, as well as two non-Hodgkin lymphoma cells lines, namely KARPAS299 and DOHH-2. We performed two types of viability assays, MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide conversion) and ATP (adenosine triphosphate detection), flow cytometry analysis of apoptosis induction and cell cycle, cell morphology, and direct interaction analysis using two approaches-visualization of living cells by two different systems, and visualization of fixed and dyed cells. Our results revealed that graphene and graphene oxides exhibit low to moderate cytotoxicity against cells, despite visible interaction between the cells and graphene oxide. This creates possibilities for the application of the selected graphene materials for drug delivery systems or theragnostics in hematological malignancies; however, further detailed studies are necessary to explain the nature of interactions between the cells and the materials.

Graphene oxide suppresses the growth and malignancy of glioblastoma stem cell-like spheroids via epigenetic mechanisms

Background

Glioblastoma stem-like cells (GSCs) are hypothesized to contribute to self-renewal and therapeutic resistance in glioblastoma multiforme (GBM) tumors. Constituting only a small percentage of cancer cells, GSCs possess “stem-like”, tumor-initiating properties and display resistance to irradiation and chemotherapy. Thus, novel approaches that can be used to suppress GSCs are urgently needed. A new carbon material—graphene oxide (GO), has been reported to show potential for use in tumor therapy. However, the exact effect of GO on GSCs and the inherent mechanism underlying its action are not clear. In this study, we aimed to investigate the usefulness of GO to inhibit the growth and promote the differentiation of GSCs, so as to suppress the malignancy of GBM.

Methods

In vitro effects of GO on sphere-forming ability, cell proliferation and differentiation were evaluated in U87, U251 GSCs and primary GSCs. The changes in cell cycle and the level of epigenetic modification H3K27me3 were examined. GO was also tested in vivo against U87 GSCs in mouse subcutaneous xenograft models by evaluating tumor growth and histological features.

Results

We cultured GSCs to explore the effect of GO and the underlying mechanism of its action. We found, for the first time, that GO triggers the inhibition of cell proliferation and induces apoptotic cell death in GSCs. Moreover, GO could promote the differentiation of GSCs by decreasing the expression of stem cell markers (SOX2 and CD133) and increasing the expression of differentiation-related markers (GFAP and β-III tubulin). Mechanistically, we found that GO had a striking effect on GSCs by inducing cell cycle arrest and epigenetic regulation. GO decreased H3K27me3 levels, which are regulated by EZH2 and associated with transcriptional silencing, in the promoters of the differentiation-related genes GFAP and β-III tubulin, thereby enhancing GSC differentiation. In addition, compared with untreated GSCs, GO-treated GSCs that were injected into nude mice exhibited decreased tumor growth in vivo.

Conclusion

These results suggested that GO could promote differentiation and reduce malignancy in GSCs via an unanticipated epigenetic mechanism, which further demonstrated that GO is a potent anti-GBM agent that could be useful for future clinical applications.

Graphene-Induced Transdifferentiation of Cancer Stem Cells as a Therapeutic Strategy against Glioblastoma

Glioblastoma (GBM) is an extremely malignant tumor of the central nervous system, characterized by low response to treatments and reoccurrence. This therapeutic resistance is believed to arise mostly from the presence of a subpopulation of tumorigenic stem cells, known as cancer stem cells (CSCs). In addition, the surrounding microenvironment is known to maintain CSCs, thus supporting tumor development and aggressiveness. This review focuses on a therapeutic strategy involving the stem cell trans-differentiating ability of graphene and its derivatives. Graphene distinguishes itself from other carbon-based nanomaterials due to an array of properties that makes it suitable for many purposes, from bioengineering to biomedical applications. Studies have shown that graphene is able to promote and direct the differentiation of CSCs. In addition, potential usage of graphene in GBM treatment represents a challenge in respect to its administration method. The present review also provides a general outlook of the potential side effects (e.g., cell toxicity) that graphene could have. Overall, this report discusses certain graphene-based therapeutic strategies targeting CSCs, which can be considered as prospective effective GBM treatments.

Use of Selected Carbon Nanoparticles as Melittin Carriers for MCF-7 and MDA-MB-231 Human Breast Cancer Cells

Despite advanced techniques in medicine, breast cancer caused the deaths of 627,000 women in 2018. Melittin, the main component of bee venom, has lytic properties for many types of cells, including cancer cells. To increase its toxic effect, carbon nanoparticles, graphene oxide, pristine graphene, and diamond were used as carriers of melittin to breast cancer cells. To date, the effects of carbon nanoparticles as carriers of melittin on cancer cells have not been studied. The present study was carried out on MCF-7 and MDA-MB-231 cell lines. The investigation consisted of structural analysis of complexes using transmission electron microscopy, zeta potential measurements, evaluation of cell morphology, assessment of cell viability and membrane integrity, investigation of reactive oxygen species production, and investigation of mitochondrial membrane potential. Cell death was examined by flow cytometry and a membrane test for 43 apoptotic proteins. The results indicate that melittin complex with nanographene oxide has a stronger toxic effect on breast cancer cells than melittin alone. Moreover, nanodiamonds can protect cells against the lytic effects of melittin. All complexes reduced, but not completely eliminated the level of necrosis, compared to melittin. Thus, results suggest that the use of carbon nanoparticles as carriers for melittin may find use in medicine in the future.

Nanoformulations for glioblastoma multiforme: a new hope for treatment

Glioblastoma multiforme (GBM) is the most common primary malignant brain tumor in adults, associated with a high mortality rate and a survival of between 12 and 15 months after diagnosis. Due to current treatment limitations involving surgery, radiotherapy and chemotherapy with temozolamide, there is a high rate of treatment failure and recurrence. To try to overcome these limitations nanotechnology has emerged as a novel alternative. Lipid, polymeric, silica and magnetic nanoparticles, among others, are being developed to improve GBM treatment and diagnosis. These nanoformulations have many advantages, including lower toxicity, biocompatibility and the ability to be directed toward the tumor. This article reviews the progress that have been made and the large variety of nanoparticles currently under study for GBM.

N-acetyl cysteine-loaded graphene oxide-collagen hybrid membrane for scarless wound healing

Wound dressings composed of natural polymers, such as type I collagen, possess good biocompatibility, water holding capacity, air permeability, and degradability, and can be used in wound repair. However, due to the persistent oxidative stress in the wound area, the migration and proliferation of fibroblasts might be suppressed, leading to poor healing. Thus, collagen-containing scaffolds are not suitable for accelerated wound healing. Antioxidant N-acetyl cysteine (NAC) is known to reduce the reactive oxygen species (ROS) and has been widely used in the clinic. Theoretically, the carboxyl group of NAC allows loading of graphene oxide (GO) for sustained release and may also enhance the mechanical properties of the collagen scaffold, making it a better wound-dressing material. Herein, we demonstrated an innovative approach for a potential skin-regenerating hybrid membrane using GO incorporated with collagen I and NAC (N-Col-GO) capable of continuously releasing antioxidant NAC. Methods: The mechanical stability, water holding capacity, and biocompatibility of the N-Col-GO hybrid membrane were measured in vitro. A 20 mm rat full-skin defect model was created to evaluate the repair efficiency of the N-Col-GO hybrid membrane. The vascularization and scar-related genes in the wound area were also examined. Results: Compared to the Col only scaffold, N-Col-GO hybrid membrane exhibited a better mechanical property, stronger water retention capacity, and slower NAC release ability, which likely promote fibroblast migration and proliferation. Treatment with the N-Col-GO hybrid membrane in the rat wound model showed complete healing 14 days after application which was 22% faster than the control group. HE and Masson staining confirmed faster collagen deposition and better epithelization, while CD31 staining revealed a noticeable increase of vascularization. Furthermore, Rt-PCR demonstrated decreased mRNA expression of profibrotic and overexpression of anti-fibrotic factors indicative of the anti-scar effect. Conclusion: These findings suggest that N-Col-GO drug release hybrid membrane serves as a better platform for scarless skin regeneration.

Mechano-signalling, induced by fullerene C60 nanofilms, arrests the cell cycle in the G2/M phase and decreases proliferation of liver cancer cells

INTRODUCTION AND OBJECTIVE

Degradation of the extracellular matrix (ECM) changes the physicochemical properties and dysregulates ECM-cell interactions, leading to several pathological conditions, such as invasive cancer. Carbon nanofilm, as a biocompatible and easy to functionalize material, could be used to mimic ECM structures, changing cancer cell behavior to perform like normal cells.

METHODS

Experiments were performed in vitro with HS-5 cells (as a control) and HepG2 and C3A cancer cells. An aqueous solution of fullerene C60 was used to form a nanofilm. The morphological properties of cells cultivated on C60 nanofilms were evaluated with light, confocal, electron and atomic force microscopy. The cell viability and proliferation were measured by XTT and BrdU assays. Immunoblotting and flow cytometry were used to evaluate the expression level of proliferating cell nuclear antigen and determine the number of cells in the G2/M phase.

RESULTS

All cell lines were spread on C60 nanofilms, showing a high affinity to the nanofilm surface. We found that C60 nanofilm mimicked the niche/ECM of cells, was biocompatible and non-toxic, but the mechanical signal from C60 nanofilm created an environment that affected the cell cycle and reduced cell proliferation.

CONCLUSION

The results indicate that C60 nanofilms might be a suitable, substitute component for the niche of cancer cells. The incorporation of fullerene C60 in the ECM/niche may be an alternative treatment for hepatocellular carcinoma.

Diamond Nanoparticles Downregulate Expression of CycD and CycE in Glioma Cells

Our previous studies have shown that diamond nanoparticles (NDs) exhibited antiangiogenic and proapoptotic properties in vitro in glioblastoma multiforme (GBM) cells and in tumors in vivo. Moreover, NDs inhibited adhesion, leading to the suppression of migration and invasion of GBM. In the present study, we hypothesized that the NDs might also inhibit proliferation and cell cycle in glioma cells. Experiments were performed in vitro with the U87 and U118 lines of GBM cells, and for comparison, the Hs5 line of stromal cells (normal cells) after 24 h and 72 h of treatment. The analyses included cell morphology, cell death, viability, and cell cycle analysis, double timing assay, and gene expression (Rb, E2F1, CycA, CycB, CycD, CycE, PTEN, Ki-67). After 72 h of ND treatment, the expression level of Rb, CycD, and CycE in the U118 cells, and E2F1, CycD, and CycE in the U87 cells were significantly lower in comparison to those in the control group. We observed that decreased expression of cyclins inhibited the G1/S phase transition, arresting the cell cycle in the G0/G1 phase in glioma cells. The NDs did not affect the cell cycle as well as PTEN and Ki-67 expression in normal cells (Hs5), although it can be assumed that the NDs reduced proliferation and altered the cell cycle in fast dividing cells.

Nanostructures of diamond, graphene oxide and graphite inhibit CYP1A2, CYP2D6 and CYP3A4 enzymes and downregulate their genes in liver cells

INTRODUCTION AND OBJECTIVE

Currently, carbon nanostructures are vastly explored materials with potential for future employment in biomedicine. The possibility of employment of diamond nanoparticles (DN), graphene oxide (GO) or graphite nanoparticles (GN) for in vivo applications raises a question of their safety. Even though they do not induce a direct toxic effect, due to their unique properties, they can still interact with molecular pathways. The objective of this study was to assess if DN, GO and GN affect three isoforms of cytochrome P450 (CYP) enzymes, namely, CYP1A2, CYP2D6 and CYP3A4, expressed in the liver.

METHODS

Dose-dependent effect of the DN, GO and GN nanostructures on the catalytic activity of CYPs was examined using microsome-based model. Cytotoxicity of DN, GO and GN, as well as the influence of the nanostructures on mRNA expression of CYP genes and CYP-associated receptor genes were studied in vitro using HepG2 and HepaRG cell lines.

RESULTS

All three nanostructures interacted with the CYP enzymes and inhibited their catalytic activity in microsomal-based models. CYP gene expression at the mRNA level was also downregulated in HepG2 and HepaRG cell lines. Among the three nanostructures, GO showed the most significant influence on the enzymes, while DN was the most inert.

CONCLUSION

Our findings revealed that DN, GO and GN might interfere with xenobiotic and drug metabolism in the liver by interactions with CYP isoenzymes responsible for the process. Such results should be considered if DN, GO and GN are used in medical applications.

Deciphering the transcription factor-microRNA-target gene regulatory network associated with graphene oxide cytotoxicity

Graphene oxide (GO) has recently emanated as a promising material in cancer treatment. To unveil the underlying mechanisms of microRNAs (miRNAs) and potential target genes involved in GO cytotoxicity, we firstly compiled GO-related miRNAs and genes in human cancer cell lines treated with GO from public databases and published works. Besides miRNAs as post-transcriptional regulators of gene expression, transcription factors (TFs) are also the main regulators at the transcriptional level. In the following, we explored the regulatory relationships between miRNAs, target genes, and TFs. Thereafter, a gene regulatory network consisting of GO-responsive miRNAs, GO-responsive genes, and known human TFs was constructed. Then, 3-node regulatory motif types were detected in the resulting network. Among them, miRNA-FFL (feed-forward loop) was identified as a significant motif type. A total of 184 miRNA-FFLs were found and merged to generate a regulatory sub-network. Pathway analysis of the resulting sub-network highlighted adherens junction, focal adhesion, and TGFβ signaling pathways as the major pathways that previous studies demonstrate them to be the affected pathways in GO-treated cells. Functional investigations displayed that miRNAs might be involved in the control of apoptosis through disruption of cell adhesion in response to cytotoxicity. Moreover, GO-cell interactions can lead to miRNA targeting of genes (i.e. Rac1 and RhoA) involved in the cytoskeleton assembly process. These specific toxic properties support biomedical applications of GO, especially for cancer therapy.

NF-κB-related decrease of glioma angiogenic potential by graphite nanoparticles and graphene oxide nanoplatelets

Gliomas develop an expanded vessel network and a microenvironment characterized by an altered redox environment, which produces high levels of reactive oxygen species (ROS) and reactive nitrogen species (RNS) that fuel its growth and malignancy. ROS and RNS can influence tumor cell malignancy via the redox-regulated transcription factor NF-κB, whose activation is further regulated by the mutation status of p53. The objective of this study was to assess the influence of graphite nanoparticles (NG) and graphene oxide nanoplatelets (nGO) on the angiogenic potential of glioma cell lines with different p53 statuses. Nanoparticle treatment of glioma cells decreased the angiogenesis of human umbilical vein endothelial cells (HUVEC) cocultured with U87 (p53 wild type) and was not effective for U118 (p53 mutant) cells. Nanoparticle activity was related to the decreased level of intracellular ROS and RNS, which downregulated NF-κB signaling depending on the p53 status of the cell line. Activation of NF-κB signaling affected downstream protein levels of interleukin 6, interleukin 8, growth-regulated oncogene α, and monocyte chemotactic protein 1. These results indicate that the activity of NG and nGO can be regulated by the mutation status of glioma cells and therefore give new insights into the use of nanoparticles in personalized biomedical applications regarding glioma angiogenesis and its microenvironment.