Totan Ghosh

Zinc sulfide nanoparticles selectively induce cytotoxic and genotoxic effects on leukemic cells: involvement of reactive oxygen species and tumor necrosis factor alpha

The aim of the present study was to develop zinc sulfide nanoparticles (ZnS NPs) and to study their cytotoxicity against the KG‐1A (human acute myeloid leukemia) cell line. ZnS NPs were synthesized using the pyrolytic method and characterized by X‐ray diffraction, dynamic light scattering, surface zeta potential, scanning electron microscopy and atomic force microscopy. Cell viability study and flow cytometric analysis confirmed the potent cytotoxic effects of ZnS NPs on cancer cells in a dose‐dependent fashion. Successful uptakes of ZnS NPs by leukemic cells were confirmed by phase contrast fluorescence microscopy. pH‐dependent dissolution of ZnS NPs was done using atomic absorption microscopy to understand the cell‐specific internalization of Zn+. This internalization of NPs facilitated the generation of excess reactive oxygen species (ROS), followed by tumor necrosis factor alpha (TNF‐α) secretion which caused severe DNA damage as observed in the comet assay and altered the mitochondrial membrane potential (MMP) in leukemic cells. Surprisingly ZnS NPs had no toxic effects on normal lymphocytes at doses up to 50 µg ml–1. Pre‐treatment with ROS and TNF‐α inhibitor confirmed that these nanoparticles were able to kill leukemic cells by generating an excess amount of ROS and thereby initiated TNF‐α mediated apoptosis pathway. These findings clarify the mechanism with which ZnS NPs induced anticancer activities in vitro. To elicit its utilities and its application to cancer treatment in vivo is under investigation. Copyright

Anticancer and immunostimulatory role of encapsulated tumor antigen containing cobalt oxide nanoparticles

The purpose of this study is to evaluate the prospect of using surface modified cobalt oxide(CoO) nanoparticles as carriers of cancerantigens to human macrophages. N-Phosnomethyliminodiacetic acid (PMIDA) was used for surface modification to overcome the toxic effect of CoO nanoparticles. Here, the phosphonate group of the PMIDA acts as a surface-anchoring agent and the remaining –COOH groups bind nonspecifically with tumor associated antigens. This modification allows the conjugation of human oral carcinoma (KB) cell lysate (CL) as an antigen with PMIDA coated CoO nanoparticles (CL–PMIDA–CoO). Particle characterization was performed by dynamic light scattering, atomic force microscopy, and scanning electron microscopy studies. Fourier transform IR spectroscopy was used to investigate conjugation of the protein with nanoparticles. Protein encapsulation was confirmed by protein gel electrophoresis. Active uptake of antigen-conjugated nanoparticles by macrophages was confirmed by fluorescence microscopy. The antitumor activity of the nanocomplex pulsed macrophages was investigated on a human oral carcinoma cell line (KB) in vitro. The modified nanocomplexes upregulate IFN-γ and TNF-α and induce an anticancer immune response by activating macrophages. The use of TNF-α inhibitor confirmed the ability of the CL–PMIDA–CoO nanocomplex to stimulate TNF-α mediated immunostimulation. CL–PMIDA–CoO nanoparticles efficiently increased the CD4+ population. Thus, our findings provide insight into the use of PMIDA coated CoO nanoparticles as antigen delivery vehicles.Graphical abstract

Chitosan-modified cobalt oxide nanoparticles stimulate TNF-α-mediated apoptosis in human leukemic cells

The objective of this study was to develop chitosan-based delivery of cobalt oxide nanoparticles to human leukemic cells and investigate their specific induction of apoptosis. The physicochemical properties of the chitosan-coated cobalt oxide nanoparticles were characterized using transmission electron microscopy, dynamic light scattering, X-ray diffraction, and Fourier transform infrared spectroscopy. The solubility of chitosan-coated cobalt oxide nanoparticles was higher at acidic pH, which helps to release more cobalt ions into the medium. Chitosan-coated cobalt oxide nanoparticles showed good compatibility with normal cells. However, our results showed that exposure of leukemic cells (Jurkat cells) to chitosan-coated cobalt oxide nanoparticles caused an increase in reactive oxygen species generation that was abolished by pretreatment of cells with the reactive oxygen species scavenger N-acetyl-l-cysteine. The apoptosis of Jurkat cells was confirmed by flow-cytometric analysis. Induction of TNF-α secretion was observed from stimulation of Jurkat cells with chitosan-coated cobalt oxide nanoparticles. We also tested the role of TNF-α in the induction of Jurkat cell death in the presence of TNF-α and caspase inhibitors. Treatment of leukemic cells with a blocker had a greater effect on cancer cell viability. From our findings, oxidative stress and caspase activation are involved in cancer cell death induced by chitosan-coated cobalt oxide nanoparticles.Graphical abstract

Folate decorated delivery of self assembled betulinic acid nano fibers: a biocompatible anti-leukemic therapy

The objective of this study was to develop folate receptor mediated delivery of self assembled betulinic acid nano fibers (SA-BA) to human leukemic cells and to investigate their specific induction of apoptosis. The physicochemical properties of PEG conjugated SA-BA followed by conjugated with folic acid (FA–PEG–SA-BA) were examined using Fourier transform infrared spectroscopy, thermogravimetry analysis, X-ray diffraction analysis, thin layer chromatography and scanning electron microscopy. The stability of folic acid with PEG–SA-BA conjugate was higher at acidic pH, which helps to maintain the conjugate structure for internalization of folate receptor over expressing cells. FA–PEG–SA-BA showed good compatibility with normal cells. The internalization of FA–PEG–SA-BA was significantly observed in folate receptor over expressing K562 cells while showing comparatively lower impact on folate receptor lower expressing KG-1A cells. This intracellular localization of conjugate facilitated the generation of excess reactive oxygen species (ROS), followed by elevation of tumor necrosis factor alpha (TNF-α) secretion. The effective contribution of ROS and TNF-α in FA–PEG–SA-BA mediated leukemic cell death was confirmed by pretreatment of cells with the ROS scavenger (N-acetyl-L-cysteine) and pentoxifylline, a potent TNF-α blocker. The mode of leukemic cell death was confirmed by flow-cytometric analysis. We also tested the possible involvement of caspase activation in TNF-α mediated leukemic cell death by immunoflouroscence staining of apoptotic marker proteins (caspase 8 and caspase 3).

Surface modification of cobalt oxide nanoparticles using phosphonomethyl iminodiacetic acid followed by folic acid: a biocompatible vehicle for targeted anticancer drug delivery

The aim of our study was to prepare multifunctional, biocompatible nanoparticles for site-specific drug delivery. Hydrophilic nanoparticles with surface-adorned amine, carboxyl, or aldehyde groups, to be later used for bio-conjugation, were designed using phosphonomethyl iminodiacetic acid (PMIDA) as the coupling agent. These PMIDA-coated cobalt oxide nanoparticles (PMIDA-CoO) were further functionalized with folic acid (FA), using simple technique. The particles show excellent aqueous dispersion stability in physiological pH without any deterioration in hydrodynamic size. The cytotoxicity and internalization efficiency of these nanocarriers have been evaluated on folate receptor over expressed KB and folate receptor lower expressed KG1a cells. Anticancer drugs such as doxorubicin and methotrexate were successfully attached to the folic acid-decoded PMIDA-CoO nanoparticles by simple reactions. Anticancer drug-loaded nanoparticles (FA-PMIDA-CoO) exhibit elevated cytotoxicity and induce apoptosis in cancer cells, which were confirmed by flow cytometry. Fluorescence microscopy study shows the higher amount of internalization of the noncomplex by KB cells, which clearly demonstrated that cells overexpressing the human folate receptor internalized a higher level of these nanoparticles–folate conjugates than folate receptor-negative control cells.

Self-assembled betulinic acid protects doxorubicin induced apoptosis followed by reduction of ROS–TNF-α–caspase-3 activity

Doxorubicin (DOX) is a well-known drug used to treat a wide range of solid tumor and hematological malignancies, but the use of this drug is now restricted owing to its severe side effects, including normal cellular toxicity. This study was conducted to evaluate the potency of self-assembled betulinic acid (SA-BA) against DOX induced chemotherapeutic toxicity in human peripheral blood lymphocytes (PBLs). The isolated betulinic acid from the bark of Ziziphus jujuba tree was purified by column chromatography and characterized by FT-IR, XRD, (1)H NMR and self-assembly property was investigated by SEM imaging. DOX treatment produced significant reduction of viability of PBLs mainly by lowering cellular anti-oxidant pool and elevating the reactive oxygen species level. Pre-treatment with SA-BA followed by DOX exposure for 24h protected the PBLs from DOX induced oxidative stress. Potent anti-apoptotic role of SA-BA was also confirmed by FACS analysis and western blot assay. Severe inflammation is one of the major concerns in DOX treatment. We found that pre-treatment with SA-BA on PBLs significantly protected the PBLs from DOX induced inflammation. Thus, our finding confirms that SA-BA can be used to ameliorate the cytotoxic effects of DOX, which can be a helpful strategy during DOX mediated chemotherapy in cancer patients.

Preparation of antiferromagnetic Co3O4 nanoparticles from two different precursors by pyrolytic method: in vitro antimicrobial activity

Two varieties of Co3O4 nano particles (Co3O4-I and Co3O4-II) have been synthesized from two different precursors using a pyrolytic technique. Co3O4-I was prepared by using a coordination polymer [Co(dca)2(2-benzoylpyridine)]n (dca = dicyanamide) as sole precursor, whereas Co3O4-II was obtained from a dinuclear complex [Co2(HL)(OAc)2](OAc)2·4H2O [HL = 2,6-bis(N-ethylpiperazine-iminomethyl)-4-methyl phenol]. The synthesized nanoparticles were characterized by FTIR spectroscopy, magnetic measurements and X-ray diffraction studies. Both Co3O4-I and Co3O4-II are high-quality mono-dispersed, stable and defect-free nanoparticles. The surface morphology of these nanoparticles was revealed by scanning electron microscopy. Co3O4-I nanoparticles have square shape and size ranging from 10 to 25 nm, whereas Co3O4-II nanoparticles have hexagonal shape with larger particle size (100–150 nm). The size distribution of the nanoparticles was determined by dynamic light scattering. The particle size and microstructure were studied by transmission electron microscopy (TEM) images. These nanoparticles show an effective anti-microbial activity, employing Staphylococcus aureus and Escherichia coli as model microbial species, evidenced from the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) values.

Antileukemic Efficacy of Monomeric Manganese-Based Metal Complex on KG-1A and K562 Cell Lines

Transitional metals and metal compounds have been used in versatile platforms for biomedical applications and therapeutic intervention. Severe side effects of anticancer drugs produce an urgent urge to develop new classes of anticancer agents with great potency as well as selectivity. In this background, recent studies demonstrate that monomeric manganese (MnII) thiocyanate complex (MMTC) holds great promise to exert effective antileukemic effects. MMTC was developed by a simple chemical reaction and characterized by elemental analyses, thermal analyses, and Fourier transform infrared (FTIR) spectroscopy. Anti-leukemic efficacy of the developed MMTC was estimated in KG-1A (AML) and K562 (CML) cell lines. Cell viability study, drug uptake assay, cellular redox balance (GSH and GSSG level), nitric oxide (NO) release level, reactive oxygen species (ROS) formation, alteration of mitochondrial membrane potential (MMP), and DNA fragmentation revealed that MMTC was able to produce significant antiproliferative effects on both cell lines at 25 μg mL−1 without showing any toxicological impact on normal lymphocytes. These findings will enlighten the biomedical application of manganese-based metal complexes as anti-leukemic agents.

Structure and luminescence of a nitrate-bridged heterotrinuclear Cu2-Pr complex with compartmental Schiff base ligand

A unique heterotrinuclear nitrate-bridged complex of hexanitrate praseodymium(III) and dicopper(II) compartmental species has been synthesized and characterized by X-ray single crystal structure analysis. The structure determination indicates that the dinuclear copper moiety undergoes a tilted deformation (with respect to the dicopper complex) upon connection to the lanthanide species via a rare nitrate bridge. The trinuclear species is highly fluorescent owing to the presence of praseodymium.