Fullerene C60 Penetration into Leukemic Cells and Its Photoinduced Cytotoxic Effects

Targeted therapy for leukemia based on nanomaterials

Leukemia is a kind of hematopoietic stem cell malignant clonal disease. Drug therapy is the core treatment strategy for leukemia, but the current therapeutic drugs have defects such as low bioavailability, large adverse reactions and inconvenient intravenous administration. Targeted therapy can combine drugs with specific carcinogenic sites on cells to kill cancer cells and avoid damage to normal cells, which has gradually become the mainstream method of leukemia treatment. In addition, nanomedicine delivery systems can significantly improve drug efficacy through controlled size and targeted optimization of drug delivery by modification strategies. Therefore, the targeted treatment of leukemia based on nanomaterials has great research value and application prospect. This paper gives an overview of the current therapeutic strategies for leukemia, and then reviews the cutting-edge targeted therapeutic nanomaterials for leukemia, including organic nanomaterials (mainly carbon-based nanomaterials, lipid materials, polymers, etc.) and inorganic nanomaterials (mainly noble metal nanoparticles, magnetic nanoparticles, hollow mesoporous materials, etc.). The challenges and prospects for the future development of targeted nanomaterials in the treatment of leukemia are also briefly reviewed.

Fullerene C60 Conjugate with Folic Acid and Polyvinylpyrrolidone for Targeted Delivery to Tumor Cells

The use of targeted drug delivery systems, including those based on selective absorption by certain receptors on the surface of the target cell, can lead to a decrease in the minimum effective dose and the accompanying toxicity of the drug, as well as an increase in therapeutic efficacy. A fullerene C60 conjugate (FA-PVP-C60) with polyvinylpyrrolidone (PVP) as a biocompatible spacer and folic acid (FA) as a targeting ligand for tumor cells with increased expression of folate receptors (FR) was obtained. Using 13C NMR spectroscopy, FT-IR, UV-Vis spectrometry, fluorometry and thermal analysis, the formation of the conjugate was confirmed and the nature of the binding of its components was established. The average particle sizes of the conjugate in aqueous solutions and cell culture medium were determined using dynamic light scattering (DLS) and nanoparticle tracking analysis (NTA). The FA-PVP-C60 showed antiradical activity against •DPPH, •OH and O2•-, but at the same time, it was shown to generate 1O2. It was found that the conjugate in the studied concentration range (up to 200 μg/mL) is non-toxic in vitro and does not affect the cell cycle. To confirm the ability of the conjugate to selectively accumulate through folate-mediated endocytosis, its uptake into cells was analyzed by flow cytometry and confocal microscopy. It was shown that the conjugate is less absorbed by A549 cells with low FR expression than by HeLa, which has a high level of expression of this receptor.

Comparative Studies of the Structural and Physicochemical Properties of the First Fullerene Derivative FD-C60 (Fullerenol) and Second Fullerene Derivate SD-C60 (3HFWC)

In order to maximally reduce the toxicity of fullerenol (the first derivative of C60, FD-C60), and increase its biomedical efficiency, the second derivative SD-C60 (3HFWC, Hyper-Harmonized Hydroxylated Fullerene Water Complex) was created. Several different methods were applied in the comparative characterization of FD-C60 and SD-C60 with the same OH groups in their core. FD-C60 as an individual structure was about 1.3 nm in size, while SD-C60 as an individual structure was 10-30 nm in size. Based on ten physicochemical methods and techniques, FD-C60 and SD-C60 were found to be two different substances in terms of size, structure, and physicochemical properties; FD-C60, at 100 °C, had endothermic characteristics, while SD-C60, at 133 °C, had exothermic characteristics; FD-C60 did not have water layers, while SD-C60 had water layers; the zeta potential of FD-C60 was -25.85 mV, while it was -43.29 mV for SD-C60. SD-C60 is a promising substance for use in cosmetics and pharmaceuticals.

Interactions between modified fullerenes and proteins in cancer nanotechnology

Fullerenes have numerous properties that fill the gap between small molecules and nanomaterials. Several types of chemical reaction allow their surface to be ornamented with functional groups designed to change them into 'ideal' nanodelivery systems. Improved stability, and bioavailability are important, but chemical modifications can render them practically soluble in water. 'Buckyball' fullerene scaffolds can interact with many biological targets and inhibit several proteins essential for tumorigeneses. Herein, we focus on the inhibitory properties of fullerene nanomaterials against essential proteins in cancer nanotechnology, as well as the use of dedicated proteins to improve the bioavailability of these promising nanomaterials.

Melanoma Cell Reprogramming and Awakening of Antitumor Immunity as a Fingerprint of Hyper-Harmonized Hydroxylated Fullerene Water Complex (3HFWC) and Hyperpolarized Light Application In Vivo

In our recent study, we showed that in vitro treatment of melanoma cells with hyperpolarized light (HPL) as well as with the second derivative of fullerene, hyper-harmonized hydroxylated fullerene water complex (3HFWC) reduced viability of cells by decreasing their proliferative capacity and inducing senescence and reprogramming towards a normal, melanocytic phenotype. Therefore, we wanted to determine whether these effects persisted in vivo in the syngeneic mouse melanoma model with a combined treatment of HPL irradiation and 3HFWC per os. Our results demonstrated the potent antitumor effects of 3HFWC nanosubstance assisted by HPL irradiation. These effects were primarily driven by the stimulation of melanoma cell growth arrest, the establishment of a senescent phenotype, and melanocytic differentiation on the one hand, and the awakening of the antitumor immune response on the other. In addition, the combined treatment reduced the protumorigenic activity of immune cells by depleting T regulatory cells, myeloid-derived suppressors, and M2 macrophages. The support of the 3HFWC substance by HPL irradiation may be the axis of the new approach design based on tumor cell reprogramming synchronized with the mobilization of the host's protective immune response.

Silent Death by Sound: C60 Fullerene Sonodynamic Treatment of Cancer Cells

The acoustic pressure waves of ultrasound (US) not only penetrate biological tissues deeper than light, but they also generate light emission, termed sonoluminescence. This promoted the idea of its use as an alternative energy source for photosensitizer excitation. Pristine C₆₀ fullerene (C₆₀), an excellent photosensitizer, was explored in the frame of cancer sonodynamic therapy (SDT). For that purpose, we analyzed C₆₀ effects on human cervix carcinoma HeLa cells in combination with a low-intensity US treatment. The time-dependent accumulation of C₆₀ in HeLa cells reached its maximum at 24 h (800 ± 66 ng/10⁶ cells). Half of extranuclear C₆₀ is localized within mitochondria. The efficiency of the C₆₀ nanostructure's sonoexcitation with 1 MHz US was tested with cell-based assays. A significant proapoptotic sonotoxic effect of C₆₀ was found for HeLa cells. C₆₀'s ability to induce apoptosis of carcinoma cells after sonoexcitation with US provides a promising novel approach for cancer treatment.

Fullerenes for the treatment of cancer: an emerging tool

Cancer is a most common cause of mortality globally. Available medicines possess severe side effects owing to their non-specific targeting. Hence, there is a need of an alternative in the healthcare system that should have high efficacy with the least side effects, also having the ability to achieve site-specific targeting and be reproducible. This is possible with the help of fullerenes. Fullerenes are having the unique physicochemical and photosensitizer properties. This article discusses the synthesis, functionalization, mechanism, various properties, and applications of C60 fullerenes in the treatment of cancer. The review article also addresses the various factors influencing the activity of fullerenes including the environmental conditions, toxicity profile, and future prospective.

Nanoarchitectonics of Fullerene Based Enzyme Mimics for Osteogenic Induction of Stem Cells

Enzyme mimicry is a topic of considerable interest in the development of multifunctional biomimetic materials. Mimicking enzyme activity is a major challenge in biomaterials research, and artificial analogs that simultaneously recapitulate the catalytic and metabolic activity of native enzymes are considered to be the ultimate goal of this field. This consensus may be challenged by self-assembling multifunctional nanostructures to develop close-to-fidelity enzyme mimics. Here, we present the ability of fullerene nanostructures decorated with active units to form enzyme-like materials that can mimic phosphatases in a metal-free manner. These nanostructures self-assemble into nanoclusters forming multiple random active sites that can cleave both phosphomonoesters and phosphodiesters while being more specific for the phosphomonoesters. Moreover, they are reusable and show an increase in catalytic activity over multiple cycles similar to their natural counterparts. In addition to having enzyme-like catalytic properties, these nanocatalysts imitate the biological functions of their natural analogs by inducing biomineralization and osteoinduction in preosteoblast and mesenchymal stem cells in vitro studies. This article is protected by copyright. All rights reserved.

Combined Action of Hyper-Harmonized Hydroxylated Fullerene Water Complex and Hyperpolarized Light Leads to Melanoma Cell Reprogramming In Vitro

(1) Background: Their unique structure and electron deficiency have brought fullerenes into the focus of research in many fields, including medicine. The hyper-harmonized hydroxylated fullerene water complex (3HFWC) formulation has solved the limitations of the poor solubility and bioavailability of fullerenes. To achieve better antitumor activity, 3HFWC was combined with short-term irradiation of cells with hyperpolarized light (HPL) generated by the application of a nanophotonic fullerene filter in a Bioptron^® device. The benefits of HPL were confirmed in the microcirculation, wound healing and immunological function. (2) Methods: B16, B16-F10 and A375 melanoma cells were exposed to a wide spectrum of 3HFWC doses and to a single short-term HPL irradiation. (3) Results: Apart from the differences in the redox status and level of invasiveness, the effects of the treatments were quite similar. Decreased viability, morphological alteration, signs of melanocytic differentiation and cellular senescence were observed upon the successful internalization of the nanoquantum substance. (4) Conclusions: Overall, 3HFWC/HPL promoted melanoma cell reprogramming toward a normal phenotype.

Antitumor efficiency of the natural alkaloid berberine complexed with C60 fullerene in Lewis lung carcinoma in vitro and in vivo

Background

Berberine (Ber) is a herbal alkaloid with pharmacological activity in general and a high anticancer potency in particular. However, due to its low bioavailability, the difficulty in reaching a target and choosing the right dose, there is a need to improve approaches of Ber use in anticancer therapy. In this study, Ber, noncovalently bound to a carbon nanostructure C60 fullerene (C60) at various molar ratios of the components, was explored against Lewis lung carcinoma (LLC).

Methods

C60–Ber noncovalent nanocomplexes were synthesized in 1:2, 1:1 and 2:1 molar ratios. Ber release from the nanocomplexes was studied after prolonged incubation at different pH with the liquid chromatography–mass spectrometry analysis of free Ber content. Biological effects of the free and C60-complaxated Ber were studied in vitro towards LLC cells with phase-contrast and fluorescence microscopy, flow cytometry, MTT reduction, caspase activity and wound closure assays. The treatment with C60–Ber nanocomplex was evaluated in vivo with the LLC-tumored C57Bl mice. The mice body weight, tumor size, tumor weight and tumor weight index were assessed for four groups, treated with saline, 15 mg C60/kg, 7.5 mg Ber/kg or 2:1 C60-Ber nanocomplex (15 mg C60/kg, 7.5 mg Ber/kg).

Results

Ber release from C60–Ber nanocomplexes was promoted with medium acidification. LLC cells treatment with C60–Ber nanocomplexes was followed by enhanced Ber intracellular uptake as compared to free Ber. The cytotoxicity of the studied agents followed the order: free Ber < 1:2 < 1:1 < 2:1 C60–Ber nanocomplex. The potency of cytotoxic effect of 2:1 C60–Ber nanocomplex was confirmed by 21.3-fold decrease of IC50 value (0.8 ± 0.3 µM) compared to IC50 for free Ber (17 ± 2 µM). C60–Ber nanocomplexes induced caspase 3/7 activation and suppressed the migration activity of LLC cells. The therapeutic potency of 2:1 C60–Ber nanocomplex was confirmed in a mouse model of LLC. The tumor growth in the group treated with 2:1 C60–Ber nanocomplex is suppressed by approximately 50% at the end of experiment, while in the tumor-bearing group treated with free Ber no therapeutic effect was detected.

Conclusions

This study indicates that complexation of natural alkaloid Ber with C60 may be a novel therapeutic strategy against lung carcinoma.

Graphical abstract

Effects of C60 Fullerene on Thioacetamide-Induced Rat Liver Toxicity and Gut Microbiome Changes

Thioacetamide (TAA) is widely used to study liver toxicity accompanied by oxidative stress, inflammation, cell necrosis, fibrosis, cholestasis, and hepatocellular carcinoma. As an efficient free radical's scavenger, C60 fullerene is considered a potential liver-protective agent in chemically-induced liver injury. In the present work, we examined the hepatoprotective effects of two C60 doses dissolved in virgin olive oil against TAA-induced hepatotoxicity in rats. We showed that TAA-induced increase in liver oxidative stress, judged by the changes in the activities of SOD, CAT, GPx, GR, GST, the content of GSH and 4-HNE, and expression of HO-1, MnSOD, and CuZnSOD, was more effectively ameliorated with a lower C60 dose. Improvement in liver antioxidative status caused by C60 was accompanied by a decrease in liver HMGB1 expression and an increase in nuclear Nrf2/NF-κB p65 ratio, suggesting a reduction in inflammation, necrosis and fibrosis. These results were in accordance with liver histology analysis, liver comet assay, and changes in serum levels of ALT, AST, and AP. The changes observed in gut microbiome support detrimental effects of TAA and hepatoprotective effects of low C60 dose. Less protective effects of a higher C60 dose could be a consequence of its enhanced aggregation and related pro-oxidant role.

Antitumor Activity and Potential Mechanism of Novel Fullerene Derivative Nanoparticles

The development of novel nanoparticles as a new generation therapeutic drug platform is an active field of chemistry and cancer research. In recent years, fullerene nanoparticles have received extensive attention due to their unique physical and chemical properties. Properly modified fullerene nanoparticles have excellent biocompatibility and significant anti-tumor activity, which makes them have broad application prospects in the field of cancer therapy. Therefore, understanding the anti-tumor mechanism of fullerene nanoparticles is of great significance for the design and development of anti-tumor drugs with low toxicity and high targeting. This review has focused on various anti-tumor mechanisms of fullerene derivatives and discusses their toxicity and their distribution in organisms. Finally, the review points out some urgent problems that need solution before fullerene derivatives as a new generation of anti-tumor nano-drug platform enter clinical research.

Nanomaterials and hepatic disease: toxicokinetics, disease types, intrinsic mechanisms, liver susceptibility, and influencing factors

The widespread use of nanomaterials (NMs) has raised concerns that exposure to them may introduce potential risks to the human body and environment. The liver is the main target organ for NMs. Hepatotoxic effects caused by NMs have been observed in recent studies but have not been linked to liver disease, and the intrinsic mechanisms are poorly elucidated. Additionally, NMs exhibit varied toxicokinetics and induce enhanced toxic effects in susceptible livers; however, thus far, this issue has not been thoroughly reviewed. This review provides an overview of the toxicokinetics of NMs. We highlight the possibility that NMs induce hepatic diseases, including nonalcoholic steatohepatitis (NASH), fibrosis, liver cancer, and metabolic disorders, and explore the underlying intrinsic mechanisms. Additionally, NM toxicokinetics and the potential induced risks in the livers of susceptible individuals, including subjects with liver disease, obese individuals, aging individuals and individuals of both sexes, are summarized. To understand how NM type affect their toxicity, the influences of the physicochemical and morphological (PCM) properties of NMs on their toxicokinetics and toxicity are also explored. This review provides guidance for further toxicological studies on NMs and will be important for the further development of NMs for applications in various fields.

Effects of fullerene C60 in blue mussels: Role of mTOR in autophagy related cellular/tissue alterations

The effects of C₆₀ on mTOR (mechanistic Target of Rapamycin) activity in mussel digestive gland were investigated. mTOR is a kinase that senses physiological and environmental signals to control eukaryotic cell growth. mTOR is present in two complexes: the phosphorylated mTORC1 regulates cell growth by activating anabolic processes, and by inhibiting catabolic processes (i.e. autophagy); mTORC2 also modulates actin cytoskeleton organization. Mussels were exposed to C₆₀ (0.01, 0.1 and 1 mg/L) for 72 h. Immunocytochemical analysis using a specific antibody revealed the cellular distribution of C₆₀ in mussel digestive gland, already at the lowest concentration. In exposed mussels, the dephosphorylation of mTORC1 and mTORC2 may explain the C₆₀ effects, i.e. the reduction of lysosomal membrane stability, the enhancement of LC3B protein, and the increase of lysosomal/cytoplasmic volume ratio; as well the cytoskeletal alterations. No oxidative stress was observed. Multivariate analysis was used to facilitate the interpretation of the biomarker data. Finally, a low density oligo-microarray was used to understand the cellular responses to fullerene. Transcriptomics identified a number of differentially expressed genes (DEGs) showing a maximum in animals exposed to 0.1 mg/L C₆₀. The most affected processes are associated with energy metabolism, lysosomal activity and cytoskeleton organization. In this study, we report the first data on the subcellular distribution of C₆₀ in mussel's cells; and on the involvement of mTOR inhibition in the alterations due to nanoparticle accumulation. Overall, mTOR deregulation, by affecting protein synthesis, energy metabolism and autophagy, may reduce the capacity of the organisms to effectively grow and reproduce.

A Multiparametric Study of Internalization of Fullerenol C60(OH)36 Nanoparticles into Peripheral Blood Mononuclear Cells: Cytotoxicity in Oxidative Stress Induced by Ionizing Radiation

The aim of this study was to investigate the uptake and accumulation of fullerenol C₆₀(OH)₃₆ into peripheral blood mononuclear cells (PBMCs). Some additional studies were also performed: measurement of fullerenol nanoparticle size, zeta potential, and the influence of fullerenol on the ionizing radiation-induced damage to PMBCs. Fullerenol C₆₀(OH)₃₆ demonstrated an ability to accumulate in PBMCs. The accumulation of fullerenol in those cells did not have a significant effect on cell survival, nor on the distribution of phosphatidylserine in the plasma membrane. However, fullerenol-induced depolarization of the mitochondrial membrane proportional to the compound level in the medium was observed. Results also indicated that increased fullerenol level in the medium was associated with its enhanced transport into cells, corresponding to its influence on the mitochondrial membrane. The obtained results clearly showed the ability of C₆₀(OH)₃₆ to enter cells and its effect on PBMC mitochondrial membrane potential. However, we did not observe radioprotective properties of fullerenol under the conditions used in our study.

Effects of Pristine C60 Fullerenes on Liver and Pancreas in α-Naphthylisothiocyanate-Induced Cholangitis

BACKGROUND

A significant role in pathogenesis of cholangitis is attributed to excessive reactive oxygen species production and oxidative stress. Therefore, antioxidants could be promising therapeutics.

AIMS

The effects of powerful free radical scavenger C₆₀ fullerene on hepatic and pancreatic manifestations of acute and chronic cholangitis in rats were aimed to be discovered.

METHODS

Acute (AC, 3 days) and chronic (CC, 28 days) cholangitis models were simulated by single (AC) and 4 weekly (CC) α-naphthylisothiocyanate per os administrations. Pristine C₆₀ fullerene aqueous colloid solution (C₆₀FAS, 0.15 mg/ml, size of aggregates 1.2-100 nm) was administered either per os or intraperitoneally at a dose of 0.5 mg/kg C₆₀ fullerene daily (AC) and every other day (CC). Prednisolone was used as a reference. Liver and pancreas autopsies were analyzed, and blood serum biochemical markers were measured. Pan-cytokeratin expression in HepG2 cells was assessed after 48-h incubation with C₆₀FAS.

RESULTS

On AC, C₆₀FAS normalized elevated bilirubin, alkaline phosphatase, and triglycerides, diminished fibrotic alterations in liver, and improved pancreas state when applied by both ways. Additionally, C₆₀FAS per os significantly reduced the signs of inflammation in liver and pancreas. On CC, C₆₀FAS also mitigated liver fibrosis and inflammation, improved pancreas state, and normalized alkaline phosphatase and triglycerides. The remedy effect of C₆₀FAS was more expressed compared to that of prednisolone on both models. Furthermore, C₆₀FAS inhibited pan-cytokeratin expression in HepG2 cells in a dose-dependent manner.

CONCLUSION

Pristine C₆₀ fullerene inhibits liver inflammation and fibrogenesis and partially improved liver and pancreas state under acute and chronic cholangitis.

C60 Fullerene as an Effective Nanoplatform of Alkaloid Berberine Delivery into Leukemic Cells

A herbal alkaloid Berberine (Ber), used for centuries in Ayurvedic, Chinese, Middle-Eastern, and native American folk medicines, is nowadays proved to function as a safe anticancer agent. Yet, its poor water solubility, stability, and bioavailability hinder clinical application. In this study, we have explored a nanosized carbon nanoparticle-C₆₀ fullerene (C₆₀)-for optimized Ber delivery into leukemic cells. Water dispersions of noncovalent C₆₀-Ber nanocomplexes in the 1:2, 1:1, and 2:1 molar ratios were prepared. UV-Vis spectroscopy, dynamic light scattering (DLS), and atomic force microscopy (AFM) evidenced a complexation of the Ber cation with the negatively charged C₆₀ molecule. The computer simulation showed that π-stacking dominates in Ber and C₆₀ binding in an aqueous solution. Complexation with C₆₀ was found to promote Ber intracellular uptake. By increasing C₆₀ concentration, the C₆₀-Ber nanocomplexes exhibited higher antiproliferative potential towards CCRF-CEM cells, in accordance with the following order: free Ber < 1:2 < 1:1 < 2:1 (the most toxic). The activation of caspase 3/7 and accumulation in the sub-G1 phase of CCRF-CEM cells treated with C₆₀-Ber nanocomplexes evidenced apoptosis induction. Thus, this study indicates that the fast and easy noncovalent complexation of alkaloid Ber with C₆₀ improved its in vitro efficiency against cancer cells.

Synergy of Chemo- and Photodynamic Therapies with C60 Fullerene-Doxorubicin Nanocomplex

A nanosized drug complex was explored to improve the efficiency of cancer chemotherapy, complementing it with nanodelivery and photodynamic therapy. For this, nanomolar amounts of a non-covalent nanocomplex of Doxorubicin (Dox) with carbon nanoparticle C60 fullerene (C60) were applied in 1:1 and 2:1 molar ratio, exploiting C60 both as a drug-carrier and as a photosensitizer. The fluorescence microscopy analysis of human leukemic CCRF-CEM cells, in vitro cancer model, treated with nanocomplexes showed Dox's nuclear and C60's extranuclear localization. It gave an opportunity to realize a double hit strategy against cancer cells based on Dox's antiproliferative activity and C60's photoinduced pro-oxidant activity. When cells were treated with 2:1 C60-Dox and irradiated at 405 nm the high cytotoxicity of photo-irradiated C60-Dox enabled a nanomolar concentration of Dox and C60 to efficiently kill cancer cells in vitro. The high pro-oxidant and pro-apoptotic efficiency decreased IC50 16, 9 and 7 × 103-fold, if compared with the action of Dox, non-irradiated nanocomplex, and C60's photodynamic effect, correspondingly. Hereafter, a strong synergy of therapy arising from the combination of C60-mediated Dox delivery and C60 photoexcitation was revealed. Our data indicate that a combination of chemo- and photodynamic therapies with C60-Dox nanoformulation provides a promising synergetic approach for cancer treatment.

Cytogenotoxic effects of fullerene C60 in the freshwater teleostean fish, Anabas testudineus (Bloch, 1792)

In recent years, carbon nanomaterials, including fullerene C₆₀ is regarded as the building block in nanotechnology because of its widespread use in medicine, industry, cosmetics and commercial products. Despite the special properties, several reports have raised public health concerns due to the unknown and practically unexplored toxic effects of nanomaterials. However, there have been relatively few studies regarding the genotoxic responses of fullerene C₆₀in vivo. Genotoxic effects of DMSO-solublized C₆₀ nanomaterial suspension at sublethal concentrations (5 and 10 mg/L) were investigated on adult freshwater fish, Anabas testudineus using micronucleus and comet assays. An assessment of micronucleus induction showed severe cytoplasmic and nuclear abnormalities in erythrocytes, gill and liver cells. Abnormalities in cytoplasm were identified as formation of sticky cells, vacuolated cytoplasm, cytoplasmic degeneration, echinocyte, acanthocyte, anisochromatic cells and abnormal erythrocyte membrane. The nuclear abnormalities included micronucleus, binucleated cells, nuclear buds, irregular nucleus, vacuolated, notched and serrated nucleus in the erythrocytes compared to the control groups. Similarly, significant increase (P < 0.05) in micronucleus frequencies were observed in gill and liver cells. The high frequency of micronucleus was observed in the gill cells followed by liver and erythrocytes, respectively, at both sublethal concentrations, and the severity was duration and concentration-dependent. In comet assay, significant increase (P < 0.05) in DNA damage was observed using the comet parameter, percent tail DNA. The highest level of comet damage with grade 3 was observed in blood, gill and liver cells on increase in duration and concentration when compared to the respective control groups. Thus the results revealed that fullerene C₆₀ nanomaterials may pose risk to aquatic organisms, especially fish, by the induction of genotoxicity. Further studies are warranted to provide new insights on the mechanisms and consequences of C₆₀ nanomaterials interactions with biological membranes.

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.

Mode of photoexcited C60 fullerene involvement in potentiating cisplatin toxicity against drug-resistant L1210 cells

Introduction: C₆₀ fullerene has received great attention as a candidate for biomedical applications. Due to unique structure and properties, C₆₀ fullerene nanoparticles are supposed to be useful in drug delivery, photodynamic therapy (PDT) of cancer, and reversion of tumor cells’ multidrug resistance. The aim of this study was to elucidate the possible molecular mechanisms involved in photoexcited C₆₀ fullerene-dependent enhancement of cisplatin toxicity against leukemic cells resistant to cisplatin.

Methods: Stable homogeneous pristine C₆₀ fullerene aqueous colloid solution (10^-4 М, purity 99.5%) was used in the study. The photoactivation of C₆₀ fullerene accumulated by L1210R cells was done by irradiation in microplates with light-emitting diode lamp (420-700 nm light, 100 mW·cm^-2). Cells were further incubated with the addition of Cis-Pt to a final concentration of 1 μg/mL. Activation of p38 MAPK was visualized by Western blot analysis. Flow cytometry was used for the estimation of cells distribution on cell cycle. Mitochondrial membrane potential (Δψ_m) was estimated with the use of fluorescent potential-sensitive probe TMRE (Tetramethylrhodamine Ethyl Ester).

Results: Cis-Pt applied alone at 1 μg/mL concentration failed to affect mitochondrial membrane potential in L1210R cells or cell cycle distribution as compared with untreated cells. Activation of ROS-sensitive proapoptotic p38 kinase and enhanced content of cells in subG1 phase were detected after irradiation of L1210R cells treated with 10^-5M C₆₀ fullerene. Combined treatment with photoexcited C₆₀ fullerene and Cis-Pt was followed by the dissipation of Δψ_m at early-term period, blockage of cell transition into S phase, and considerable accumulation of cells in proapoptotic subG1 phase at prolonged incubation.

Conclusion: The effect of the synergic cytotoxic activity of both agents allowed to suppose that photoexcited C₆₀ fullerene promoted Cis-Pt accumulation in leukemic cells resistant to Cis-Pt. The data obtained could be useful for the development of new approaches to overcome drug-resistance of leukemic cells.

Toxicity of C60 fullerene-cisplatin nanocomplex against Lewis lung carcinoma cells

Cisplatin (Cis-Pt) is the cytotoxic agent widely used against tumors of various origin, but its therapeutic efficiency is substantially limited by a non-selective effect and high toxicity. Conjugation of Cis-Pt with nanocarriers is thought to be one option to enable drug targeting. The aim of this study was to estimate toxic effects of the nanocomplex formed by noncovalent interaction of C₆₀ fullerene with Cis-Pt against Lewis lung carcinoma (LLC) cells in comparison with free drug. Scanning tunneling microscopy showed that the minimum size of C₆₀-Cis-Pt nanoparticles in aqueous colloid solution was 1.1 nm whereas that of C₆₀ fullerene was 0.72 nm, thus confirming formation of the nanocomplex. The cytotoxic effect of C₆₀-Cis-Pt nanocomplex against LLC cells was shown to be higher with IC₅₀ values 3.3 and 4.5 times lower at 48 h and 72 h, respectively, as compared to the free drug. 12.5 µM Cis-Pt had no effect on LLC cell viability and morphology while C₆₀-Cis-Pt nanocomplex in Cis-Pt-equivalent concentration substantially decreased the cell viability, impaired their shape and adhesion, inhibited migration and induced accumulation in proapoptotic subG1 phase. Apoptosis induced by the C₆₀-Cis-Pt nanocomplex was confirmed by caspase 3/7 activation and externalization of phosphatidylserine on the outer surface of LLC cells with the double Annexin V-FITC/PI staining. We assume that C₆₀ fullerene as a component of the C₆₀-Cis-Pt nanocomplex promoted Cis-Pt entry and intracellular accumulation thus contributing to intensification of the drug's toxic effect against lung cancer cells.

C60 fullerenes selectively inhibit BKCa but not Kv channels in pulmonary artery smooth muscle cells

Possessing unique physical and chemical properties, C₆₀ fullerenes are arising as a potential nanotechnological tool that can strongly affect various biological processes. Recent molecular modeling studies have shown that C₆₀ fullerenes can interact with ion channels, but there is lack of data about possible effects of C₆₀ molecule on ion channels expressed in smooth muscle cells (SMC). Here we show both computationally and experimentally that water-soluble pristine C₆₀ fullerene strongly inhibits the large conductance Ca²⁺-dependent K⁺ (BK_Ca), but not voltage-gated K⁺ (K_v) channels in pulmonary artery SMC. Both molecular docking simulations and analysis of single channel activity indicate that C₆₀ fullerene blocks BK_Ca channel pore in its open state. In functional tests, C₆₀ fullerene enhanced phenylephrine-induced contraction of pulmonary artery rings by about 25% and reduced endothelium-dependent acetylcholine-induced relaxation by up to 40%. These findings suggest a novel strategy for biomedical application of water-soluble pristine C₆₀ fullerene in vascular dysfunction.

C60 fullerene accumulation in human leukemic cells and perspectives of LED-mediated photodynamic therapy

Recent progress in nanobiotechnology has attracted interest to a biomedical application of the carbon nanostructure C₆₀ fullerene since it possesses a unique structure and versatile biological activity. C₆₀ fullerene potential application in the frame of cancer photodynamic therapy (PDT) relies on rapid development of new light sources as well as on better understanding of the fullerene interaction with cells. The aim of this study was to analyze C₆₀ fullerene effects on human leukemic cells (CCRF-CEM) in combination with high power single chip light-emitting diodes (LEDs) light irradiation of different wavelengths: ultraviolet (UV, 365 nm), violet (405 nm), green (515 nm) and red (632 nm). The time-dependent accumulation of fullerene C₆₀ in CCRF-CEM cells up to 250 ng/10⁶ cells at 24 h with predominant localization within mitochondria was demonstrated with immunocytochemical staining and liquid chromatography mass spectrometry. In a cell viability assay we studied photoexcitation of the accumulated C₆₀ nanostructures with ultraviolet or violet LEDs and could prove that significant phototoxic effects did arise. A less pronounced C₆₀ fullerene phototoxic effect was observed after irradiation with green, and no effect was detected with red light. A C₆₀ fullerene photoactivation with violet light induced substantial ROS generation and apoptotic cell death, confirmed by caspase3/7 activation and plasma membrane phosphatidylserine externalization. Our work proved C₆₀ fullerene ability to induce apoptosis of leukemic cells after photoexcitation with high power single chip 405 nm LED as a light source. This underlined the potential for application of C₆₀ nanostructure as a photosensitizer for anticancer therapy.

A Novel Nanoconjugate of Landomycin A with C60 Fullerene for Cancer Targeted Therapy: In Vitro Studies

Introduction

Landomycins are a subgroup of angucycline antibiotics that are produced by Streptomyces bacteria and possess strong antineoplastic potential. Literature data suggest that enhancement of the therapeutic activity of this drug may be achieved by means of creating specific drug delivery systems. Here we propose to adopt C₆₀ fullerene as flexible and stable nanocarrier for landomycin delivery into tumor cells.

Methods

The methods of molecular modelling, dynamic light scattering and Fourier transform infrared spectroscopy were used to study the assembly of C₆₀ fullerene and the anticancer drug Landomycin A (LA) in aqueous solution. Cytotoxic activity of this nanocomplex was studied in vitro towards two cancer cell lines in comparison to human mesenchymal stem cells (hMSCs) using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) test and a live/dead assay. The morphology of the cells incubated with fullerene-drug nanoparticles and their uptake into target cells were studied by scanning electron microscopy and fluorescence light microscopy.

Results

The viability of primary cells (hMSCs, as a model for healthy cells) and cancer cell lines (human osteosarcoma cells, MG-63, and mouse mammary cells, 4T1, as models for cancer cells) was studied after incubation with water-soluble C₆₀ fullerenes, LA and the mixture C₆₀ + LA. The C₆₀ + LA nanocomplex in contrast to LA alone showed higher toxicity towards cancer cells and lower toxicity towards normal cells, whereas the water-soluble C₆₀ fullerenes at the same concentration were not toxic for the cells.

Conclusions

The obtained physico-chemical data indicate a complexation between the two compounds, leading to the formation of a C₆₀ + LA nanocomposite. It was concluded that immobilization of LA on C₆₀ fullerene enhances selectivity of action of this anticancer drug in vitro, indicating on possibility of further preclinical studies of novel C₆₀ + LA nanocomposites on animal tumor models.

C60 Fullerenes Diminish Muscle Fatigue in Rats Comparable to N-acetylcysteine or β-Alanine

The aim of this study is to detect the effects of C60 fullerenes, which possess pronounced antioxidant properties, in comparison with the actions of the known exogenous antioxidants N-acetylcysteine (NAC) and β-Alanine in terms of exercise tolerance and contractile property changes of the m. triceps surae (TS) during development of the muscle fatigue in rats. The electrical stimulation of the TS muscle during four 30 min series in control rats led to total reduction of the muscle contraction force. Furthermore, the effects of prior intraperitoneal (i.p.) or oral C60FAS application and preliminary i.p. injection of NAC or β-Alanine on muscle contraction force under fatigue development conditions is studied. In contrast to control rats, animals with C60FAS, NAC, or β-Alanine administration could maintain a constant level of muscle effort over five stimulation series. The accumulation of secondary products and changes in antioxidant levels in the muscle tissues were also determined after the fatigue tests. The increased levels of lactic acid, thiobarbituric acid reactive substances and H2O2 after stimulation were statistically significant with respect to intact muscles. In the working muscle, there was a significant (p < 0.05) increase in the activity of endogenous antioxidants: reduced glutathione, catalase, glutathione peroxidase, and superoxide dismutase. Treated animal groups showed a decrease in endogenous antioxidant activity relative to the fatigue-induced animals (P < 0.05). Oral C60FAS administration clearly demonstrated an action on skeletal muscle fatigue development similar to the effects of i.p. injections of the exogenous antioxidants NAC or β-Alanine. This creates opportunities to oral use of C60FAS as a potential therapeutic agent. Due to the membranotropic activity of C60 fullerenes, non-toxic C60FAS has a more pronounced effect on the prooxidant-antioxidant homeostasis of muscle tissues in rats.

Effect of C60 fullerene nanoparticles on the diet-induced obesity in rats

BACKGROUND

Obesity is a growing global health problem. Since increased oxidative stress is one of the key pathological mechanisms underpinning overweight and strongly correlates with progression of obesity-related complications we hypothesized that C₆₀ fullerene nanoparticles, due to their strong antioxidant capacity, could be the promising therapeutic agent in the treatment of this disease. Here we investigated whether the C₆₀ fullerenes can alleviate diet-induced obesity (DIO) and metabolic impairments associated with it.

METHODS

To determine the effect of C₆₀ fullerenes on some nutritional and metabolic parameters, rats were fed either a normal diet (6.7% fat, 15.27 kJ·g^-1) or a high-fat diet (38.8% fat, 28.71 kJ·g^-1) for 70 days and were simultaneously treated per os with pristine C₆₀ fullerene aqueous solution (C₆₀FAS; 0.3 mg·kg^-1 every other day) since the 28^th day from the start of the experiment.

RESULTS

Rats fed with high fat diet had significantly increased body mass index (BMI), levels of insulin, glucose, glycosilated hemoglobin (HbA1c) and serum pro-inflammatory cytokines compared with control rats fed with low-fat chow. C₆₀ fullerenes normalized the metabolic parameters and partially reduced BMI in DIO animals. Pro-inflammatory cytokines (IL-1b, IL-12, INFγ) were also decreased in serum of DIO rats treated with C₆₀ fullerenes while anti-inflammatory cytokines (IL-4, IL-10) were at the control levels. High fat diet caused the increased level of oxidative stress products, and this was accompanied by decreased activity both the superoxide dismutase and catalase, whereas the administration of C₆₀ fullerenes markedly decreased level of oxidative stress and enhanced antioxidant enzyme activities.

CONCLUSION

These data indicate that water-soluble pristine C₆₀ fullerenes reduce chronic inflammation, restore glucose homeostasis as well as positively affects on prooxidant-antioxidant homeostasis. C₆₀ fullerenes could be represented as a promising therapeutic agent in the treatment of obesity and its related complications.

Fullerenes in Biology and Medicine

Fullerenes and related carbon based derivatives have shown a growing relevance in biology and medicine, mainly due to the unique electronic and structural properties that make them excellent candidates for multiple functionalization. This review focuses on the most recent developments of fullerene derivatives for different biological applications.

C60@lysozyme: a new photosensitizing agent for photodynamic therapy

C₆₀@lysozyme showed significant visible light-induced singlet oxygen generation in a physiological environment, indicating the potential of this hybrid as an agent for photodynamic therapy.