Elucidating the significance of molecular interaction between sulphur doped zinc oxide nanoparticles and serum albumin using multispectroscopic approach.

Ingenious nanomaterials with improved biocompatibility and multifunctional properties are gaining vital significance in biomedical applications, including advanced drug delivery and nanotheranostics. In a biological system, these nanoparticles interact with serum proteins forming a dynamic corona that affects their biological or toxicological properties producing undesirable effects. Thus, the current study focuses on the synthesis of sulphur-doped zinc oxide nanoparticles (ZnO/S NPs) and characterizing their mechanism of interaction with serum proteins using multispectroscopic approach. ZnO/S NPs were synthesized by employing a co-precipitation approach and characterized using various analytical techniques. The results of interaction studies demonstrated that ZnO/S NPs interact with serum albumins via the static quenching process. Analysis of thermodynamic parameters (ΔG, ΔH and ΔS) revealed that the binding process is spontaneous, exothermic and van der Waals force or hydrogen bonding plays a major role. The interaction of ZnO/S NPs with tyrosine residue in bovine serum albumin was established by synchronous fluorescence spectroscopy. In addition, the results of UV-visible, circular dichroism, Fourier transform infrared, Forster's resonance energy transfer theory and dynamic light scattering spectroscopic studies revealed that the ZnO/S NPs interact with albumin by inducing the conformational changes in secondary structure and reducing the α-helix content.

Molecular interaction studies of zinc sulphide nanoparticles with DNA and its consequence: a multitechnique approach.

Molecular interaction studies between nanoparticles (NPs) and biomolecules are of great importance in the field of nanomedicine as they affect many physiological processes. Therefore, the interaction of zinc sulphide nanoparticles (ZnS NPs) with calf thymus deoxyribonucleic acid (CT DNA) and its significance was analyzed using ultraviolet (UV)-visible light, fluorescence, circular dichroism (CD), zeta potential, viscometry, electrochemical, and polymerase chain reaction methods. Fluorescence quenching analysis revealed that the fluorescence of ZnS NPs was quenched using CT DNA through a static quenching mechanism. The negative values of thermodynamic parameters (ΔG, ΔH, and ΔS) showed that the binding process was spontaneous, exothermic, and van der Waals or hydrogen bonding plays an important role in the interaction of ZnS NPs with CT DNA. Thermal melting (Tm ) studies indicated a decrease in the Tm of CT DNA, suggesting the destabilization of CT DNA upon interaction with ZnS NPs. In addition, the results obtained from competitive binding, zeta potential, CD, and viscometry measurements showed that the interaction of ZnS NPs with CT DNA is through groove binding. Electrochemical analysis further confirmed the observed results from various spectroscopic and other related studies, in which decrease in the redox peak current along with changes in peak potential (CV) and increase in the electrical resistance (EIS) indicated the interaction between ZnS NPs and CT DNA. Furthermore, PCR analysis using DNA polymerase revealed the potential of ZnS NPs to inhibit DNA replication in vitro. ZnS NP-CT DNA interaction studies can be explored to define new horizons in biomedical applications of ZnS NPs.

Novel pyrazolo[3,4-d]pyrimidine derivatives inhibit human cancer cell proliferation and induce apoptosis by ROS generation.

The paucity of effective anticancer drugs for successful treatment is a major concern, indicating the strong need for novel therapeutic compounds. In the quest of new molecules, the present study aimed to explore the potential of pyrazolo[3,4-d]pyrimidine derivatives as antiproliferative agents. In vitro anticancer screening of selected compounds was done by the National Cancer Institute's Developmental Therapeutics Programme against a panel of 60 cancer cell lines. The lead compound PP-31d considerably inhibited the growth of cancer cells, such as NCI-H460 (non-small-cell lung cancer), OVCAR-4 (ovarian cancer), 786-0 (renal cancer), A549 (non-small-cell lung cancer), and ACHN (renal cancer), showing strong anticancer potential, among other derivatives. Kinetic studies of PP-31d on NCI-H460 cells revealed a dose-dependent effect with an IC50 of 2 µM. The observed inhibition by PP-31d is attributed to the generation of reactive oxygen species and the subsequent induction of cellular apoptosis, as evidenced by the increase in the hypodiploid (subG1) population, the early apoptotic cell population, and caspase-3/7 activity, the loss of the mitochondrial membrane potential, and the degradation of nuclear DNA. Collectively, our results demonstrated that pyrazolo[3,4-d]pyrimidine derivatives inhibit cancer cell proliferation by inducing apoptosis and, thus, have the potential to be further explored for anticancer properties.

Epigallocatechin gallate protects BEAS-2B cells from lipopolysaccharide-induced apoptosis through upregulation of gastrin-releasing peptide.

Gastrin-releasing peptide (GRP) plays a major role in the development and maintenance of lung epithelial cells by promoting cell division, whereas its suppression causes growth arrest and apoptosis. The present study shows that human bronchial epithelial BEAS-2B cells challenged with lipopolysaccharide (LPS), an endotoxin from gram-negative bacteria, downregulated GRP expression and induced apoptosis via upregulation of p53 and active caspase-3, signifying the importance of GRP in lung epithelial cell survival. However, in the presence of epigallocatechin-3-gallate (EGCG), a polyphenol in green tea, BEAS-2B cells resisted LPS-induced apoptosis and restored the expression of GRP and its downstream effectors such as epidermal growth factor receptor and NF-κB, as analysed by immunoblotting and qPCR. Based on our findings, we objectify that cytoprotective functions of EGCG, via upregulation of GRP in cells challenged with LPS, are novel and can be further explored in a therapeutic point of view for diseases such as septic shock.

A Redox Modulatory Mn3 O4 Nanozyme with Multi-Enzyme Activity Provides Efficient Cytoprotection to Human Cells in a Parkinson's Disease Model.

Nanomaterials with enzyme-like activities (nanozymes) attracts significant interest due to their therapeutic potential for the treatment of various diseases. Herein, we report that a Mn3 O4 nanozyme functionally mimics three major antioxidant enzymes, that is, superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) and the multienzyme activity is size as well as morphology-dependent. The redox modulatory effect of Mn3 O4 plays a crucial role in protecting the cells from MPP+ induced cytotoxicity in a Parkinson disease (PD)-like cellular model, indicating that manganese-based nanomaterials having multi-enzyme activity can robustly rescue the cells from oxidative damage and thereby possess therapeutic potential to prevent ROS-mediated neurological disorders.

The TF-antigen binding lectin from Sclerotium rolfsii inhibits growth of human colon cancer cells by inducing apoptosis in vitro and suppresses tumor growth in vivo.

Glycan array analysis of Sclerotium rolfsii lectin (SRL) revealed its exquisite binding specificity to the oncofetal Thomsen-Friedenreich (Galß1-3GalNAcα-O-Ser/Thr, T or TF) antigen and its derivatives. This study shows that SRL strongly inhibits the growth of human colon cancer HT29 and DLD-1 cells by binding to cell surface glycans and induction of apoptosis through both the caspase-8 and -9 mediated signaling. SRL showed no or very weak binding to normal human colon tissues but strong binding to cancerous and metastatic tissues. Intratumor injection of SRL at subtoxic concentrations in NOD-SCID mice bearing HT29 xenografts resulted in total tumor regression in 9 days and no subsequent tumor recurrence. As the increased expression of TF-associated glycans is commonly seen in human cancers, SRL has the potential to be developed as a therapeutic agent for cancer.

Implementing Logic Gates for Safer Immunotherapy of Cancer.

Targeting solid tumors with absolute precision is a long-standing challenge in cancer immunotherapy. The identification of antigens, which are expressed by a large fraction of tumors of a given type and, preferably, across various types, but not by normal cells, holds the key to developing safe, off-the-shelf immunotherapies. Although the quest for widely shared, strictly tumor-specific antigens has been the focus of tremendous effort, only few such candidates have been implicated. Almost all antigens that are currently explored as targets for chimeric antigen receptor (CAR) or T cell receptor (TCR)-T cell therapy are also expressed by healthy cells and the risk of on-target off-tumor toxicity has remained a major concern. Recent studies suggest that this risk could be obviated by targeting instead combinations of two or more antigens, which are co-expressed by tumor but not normal cells and, as such, are tumor-specific. Moreover, the expression of a shared tumor antigen along with the lack of a second antigen that is expressed by normal tissues can also be exploited for precise recognition. Additional cues, antigenic or non-antigenic ones, which characterize the tumor microenvironment, could be harnessed to further increase precision. This review focuses on attempts to define the targetable signatures of tumors and assesses different strategies employing advanced synthetic biology for translating such information into safer modes of immunotherapy, implementing the principles of Boolean logic gates.

Evaluation of cell wall-associated direct extracellular electron transfer in thermophilic Geobacillus sp.

In this study, a cell wall-associated extracellular electron transfer (EET) was determined in the thermophilic Geobacillus sp. to utilize iron as a terminal electron acceptor. The direct extracellular transfer of its electrons was primarily linked to the cell wall cytochrome-c and diffusible redox mediators like flavins during the anoxic condition. Based on the azo dye decolouration and protein film voltammetry, it was revealed that, in the absence of surface polysaccharide and diffusible mediators, the cell wall-associated EET pathway was likely to be a favorable mechanism in Geobacillus sp. Since the permeability of such redox molecule is primarily limited to the cell wall, the electron transfer occurs by direct contact with cell wall-associated cytochrome and final electron acceptor. Furthermore, transfer of electrons with the help of redox shuttling molecules like riboflavin from cytochrome to cells, vice versa indicates that Geoabcillus sp. has adopted this unique pathway during an anoxic environment for its respiration. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13205-021-02917-2.

A manganese oxide nanozyme prevents the oxidative damage of biomolecules without affecting the endogenous antioxidant system.

Biocompatible nanoparticles with an intrinsic ability to mimic the cellular antioxidant enzymes are potential candidates for the development of new therapeutics for various oxidative stress related disorders. However, the understanding of the interaction and the mechanistic crosstalk between the nanoparticles and the cellular biomolecules is limited. Here we show that the multienzyme mimic manganese(ii,iii) oxide, Mn3O4, in nanoform (Mp) rescues the cells from oxidative damage induced by reactive oxygen species (ROS). The nanoparticles provide remarkable protection to biomolecules against the ROS-mediated protein oxidation, lipid peroxidation and DNA damage. Interestingly, the endogenous antioxidant machinery remains unaltered in the presence of these nanozymes, indicating the small molecule targeting of these nanoparticles in the cellular redox modulation. This study delineates the possible mechanism by which the nanoparticles provide protection to the cells against the adverse effects of oxidative stress. Based on our observation, we suggest that the multienzyme mimic Mn3O4 nanoparticles possess great potential in suppressing the oxidative stress-mediated pathophysiological conditions under which the antioxidant system is overwhelmed.

Effects of methyl jasmonate and carotenogenic inhibitors on gene expression and carotenoid accumulation in coriander (Coriandrum sativum L.) foliage.

Coriander (Coriandrum sativum L.), a commonly used annual herb that accumulates carotenoids upon methyl jasmonate (MeJA) treatment, provides an excellent model to investigate carotenogenesis and gene regulation. To explore key mechanisms involved in enhancing carotenoids, transcriptional expression profile of ten carotenogenic genes in the presence of MeJA and various gene specific inhibitors were investigated. Foliar application of MeJA (10 µM) increased expression levels of CsPDS (phytoene desaturase), CsZDS (ς-carotene desaturase), CsCHYE (carotene ε - hydroxylase) and CsLCYE (lycopene ß-cyclase) genes, and their transcript levels were strongly associated with carotenoid content, where, three days after treatment, 3.9 & 6.1 fold increase was observed for ß-carotene and lutein respectively. The regulatory effect of key genes, CsPDS, CsZDS, CsLCYE and LCYB were further confirmed by using gene-specific inhibitors fosmidomycin, norflurazon and amitrol. Norflurazon- the phytoene desaturation inhibitor leads to a decrease in ß-carotene and lutein content correlated with CsPDS, CsZDS gene induction. Our results clearly demonstrate that MeJA induced-signalling network evokes carotenogenic genes, leading to the accumulation of carotenoids. This knowledge may help to develop precise strategies for remodelling carotenoid pathway so that desired levels of a particular carotenoid in leafy vegetables is achievable.

Novel Folate Binding Protein in Arabidopsis Expressed during Salicylic Acid-Induced Folate Accumulation.

Increasing the quantity of natural folates in plant foods is recently gaining significant interest, owing to their acute deficiencies in various populations. This study observed that foliar salicylic acid treatment enhanced the accumulation of folates in Arabidopsis, which correlated with the increase in a folate binding protein (FBP) and the expression of mRNA of a putative folate binding protein At5G27830. A protein band corresponding to ∼43 kDa was observed after resolving the affinity-purified protein on SDS-PAGE, and the partial amino acid sequence indicated that the protein is indeed At5G27830. Docking studies performed with At5G27830 confirmed specific binding of folic acid to predicted site. Heterologous expression of At5G27830 in the yeast resulted in significant uptake and accumulation of folic acid in cells. This novel study of a plant FBP will be useful for folate metabolic engineering of a wide range of crops.

Sclerotium rolfsii lectin induces stronger inhibition of proliferation in human breast cancer cells than normal human mammary epithelial cells by induction of cell apoptosis.

Sclerotium rolfsii lectin (SRL) isolated from the phytopathogenic fungus Sclerotium rolfsii has exquisite binding specificity towards O-linked, Thomsen-Freidenreich (Galß1-3GalNAcα1-Ser/Thr, TF) associated glycans. This study investigated the influence of SRL on proliferation of human breast cancer cells (MCF-7 and ZR-75), non-tumorigenic breast epithelial cells (MCF-10A) and normal mammary epithelial cells (HMECs). SRL caused marked, dose-dependent, inhibition of proliferation of MCF-7 and ZR-75 cells but only weak inhibition of proliferation of non-tumorigenic MCF-10A and HMEC cells. The inhibitory effect of SRL on cancer cell proliferation was shown to be a consequence of SRL cell surface binding and subsequent induction of cellular apoptosis, an effect that was largely prevented by the presence of inhibitors against caspases -3, -8, or -9. Lectin histochemistry using biotin-labelled SRL showed little binding of SRL to normal human breast tissue but intense binding to cancerous tissues. In conclusion, SRL inhibits the growth of human breast cancer cells via induction of cell apoptosis but has substantially less effect on normal epithelial cells. As a lectin that binds specifically to a cancer-associated glycan, has potential to be developed as an anti-cancer agent.