Regulation of Glutathione S-Transferase Omega 1 Mediated by Cysteine Residues Sensing the Redox Environment.

Glutathione S-transferase omega 1 (GstO1) catalyzes deglutathionylation and plays an important role in the protein glutathionylation cycle in cells. GstO1 contains four conserved cysteine residues (C32, C90, C191, C236) found to be mutated in patients with associated diseases. In this study, we investigated the effects of cysteine mutations on the structure and function of GstO1 under different redox conditions. Wild-type GstO1 (WT) was highly sensitive to hydrogen peroxide (H2O2), which caused precipitation and denaturation at a physiological temperature. However, glutathione efficiently inhibited the H2O2-induced denaturation of GstO1. Cysteine mutants C32A and C236A exhibited redox-dependent stabilities and enzyme activities significantly different from those of WT. These results indicate that C32 and C236 play critical roles in GstO1 regulation by sensing redox environments and explain the pathological effect of cysteine mutations found in patients with associated diseases.

Study of Amiloride Binding to Human Serum Albumin: Insights from Thermodynamic, Spectroscopic, and Molecular Docking Investigations.

This study was undertaken to investigate the interaction between the sodium channel blocker amiloride (AML) and human serum albumin (HSA). A combination of multi-spectroscopic techniques and computational methods were employed to identify the AML binding site on HSA and the forces responsible for the formation of the HSA-AML complex. Our findings revealed that AML specifically binds to Sudlow's site II, located in subdomain IIIA of HSA, and that the complex formed is stabilized using van der Waals hydrogen-bonding and hydrophobic interactions. FRET analysis showed that the distance between AML and Trp214 was optimal for efficient quenching. UV-Vis spectroscopy and circular dichroism indicated minor changes in the structure of HSA after AML binding, and molecular dynamics simulations (MDS) conducted over 100 ns provided additional evidence of stable HSA-AML-complex formation. This study enhances understanding of the interaction between AML and HSA and the mechanism responsible.

Identification of New Mycobacterium tuberculosis Proteasome Inhibitors Using a Knowledge-Based Computational Screening Approach.

Mycobacterium tuberculosis (Mtb) is a deadly tuberculosis (TB)-causing pathogen. The proteasome is vital to the survival of Mtb and is therefore validated as a potential target for anti-TB therapy. Mtb resistance to existing antibacterial agents has enhanced drastically, becoming a worldwide health issue. Therefore, new potential therapeutic agents need to be developed that can overcome the complications of TB. With this purpose, in the present study, 224,205 natural compounds from the ZINC database have been screened against the catalytic site of Mtb proteasome by the computational approach. The best scoring hits, ZINC3875469, ZINC4076131, and ZINC1883067, demonstrated robust interaction with Mtb proteasome with binding energy values of -7.19, -7.95, and -7.21 kcal/mol for the monomer (K-chain) and -8.05, -9.10, and -7.07 kcal/mol for the dimer (both K and L chains) of the beta subunit, which is relatively higher than that of reference compound HT1171 (-5.83 kcal/mol (monomer) and -5.97 kcal/mol (dimer)). In-depth molecular docking of top-scoring compounds with Mtb proteasome reveals that amino acid residues Thr1, Arg19, Ser20, Thr21, Gln22, Gly23, Asn24, Lys33, Gly47, Asp124, Ala126, Trp129, and Ala180 are crucial in binding. Furthermore, a molecular dynamics study showed steady-state interaction of hit compounds with Mtb proteasome. Computational prediction of physicochemical property assessment showed that these hits are non-toxic and possess good drug-likeness properties. This study proposed that these compounds could be utilized as potential inhibitors of Mtb proteasome to combat TB infection. However, there is a need for further bench work experiments for their validation as inhibitors of Mtb proteasome.

Insight into the function of tetranectin in human diseases: A review and prospects for tetranectin-targeted disease treatment.

Tetranectin (TN), a serum protein, is closely associated with different types of cancers. TN binds plasminogen and promotes the proteolytic activation of plasminogen into plasmin, which suggests that TN is involved in remodeling the extracellular matrix and cancer tissues during cancer development. TN is also associated with other diseases, such as developmental disorders, cardiovascular diseases, neurological diseases, inflammation, and diabetes. Although the functional mechanism of TN in diseases is not fully elucidated, TN binds different proteins, such as structural protein, a growth factor, and a transcription regulator. Moreover, TN changes and regulates protein functions, indicating that TN-binding proteins mediate the association between TN and diseases. This review summarizes the current knowledge of TN-associated diseases and TN functions with TN-binding proteins in different diseases. In addition, potential TN-targeted disease treatment by inhibiting the interaction between TN and its binding proteins is discussed.

Unleashed Treasures of Solanaceae: Mechanistic Insights into Phytochemicals with Therapeutic Potential for Combatting Human Diseases.

Plants that possess a diverse range of bioactive compounds are essential for maintaining human health and survival. The diversity of bioactive compounds with distinct therapeutic potential contributes to their role in health systems, in addition to their function as a source of nutrients. Studies on the genetic makeup and composition of bioactive compounds have revealed them to be rich in steroidal alkaloids, saponins, terpenes, flavonoids, and phenolics. The Solanaceae family, having a rich abundance of bioactive compounds with varying degrees of pharmacological activities, holds significant promise in the management of different diseases. Investigation into Solanum species has revealed them to exhibit a wide range of pharmacological properties, including antioxidant, hepatoprotective, cardioprotective, nephroprotective, anti-inflammatory, and anti-ulcerogenic effects. Phytochemical analysis of isolated compounds such as diosgenin, solamargine, solanine, apigenin, and lupeol has shown them to be cytotoxic in different cancer cell lines, including liver cancer (HepG2, Hep3B, SMMC-772), lung cancer (A549, H441, H520), human breast cancer (HBL-100), and prostate cancer (PC3). Since analysis of their phytochemical constituents has shown them to have a notable effect on several signaling pathways, a great deal of attention has been paid to identifying the biological targets and cellular mechanisms involved therein. Considering the promising aspects of bioactive constituents of different Solanum members, the main emphasis was on finding and reporting notable cultivars, their phytochemical contents, and their pharmacological properties. This review offers mechanistic insights into the bioactive ingredients intended to treat different ailments with the least harmful effects for potential applications in the advancement of medical research.

Inhibition of glutathione S-transferase omega 1-catalyzed protein deglutathionylation suppresses adipocyte differentiation.

Glutathione S-transferase omega 1 (GstO1) is closely associated with various human diseases, including obesity and diabetes, but its functional mechanism is not fully understood. In the present study, we found that the GstO1-specific inhibitor C1-27 effectively suppressed the adipocyte differentiation of 3T3-L1 preadipocytes. GstO1 expression was immediately upregulated upon the induction of adipocyte differentiation, and barely altered by C1-27. However, C1-27 significantly decreased the stability of GstO1. Moreover, GstO1 catalyzed the deglutathionylation of cellular proteins during the early phase of adipocyte differentiation, and C1-27 inhibited this activity. These results demonstrate that GstO1 is involved in adipocyte differentiation by catalyzing the deglutathionylation of proteins critical for the early phase of adipocyte differentiation. [BMB Reports 2023; 56(8): 457-462].

Tetranectin targeting by epigallocatechin gallate suppresses colon cancer cell proliferation.

Tetranectin is a serum protein that binds to plasminogen and enhances its proteolytic activation, which underlies the involvement of tetranectin in the development of several carcinomas including colon cancer. In the present study, structure-based in silico screening of natural products showed that epigallocatechin gallate with anticancer effects binds to tetranectin. Binding to epigallocatechin gallate to tetranectin was confirmed by intrinsic fluorescence quenching assays and isothermal titration calorimetry. Furthermore, epigallocatechin gallate efficiently inhibited the activity of tetranectin to enhance the activation of plasminogen. We also found that tetranectin enhanced the proliferation of CT-26 colon cancer cells. Epigallocatechin gallate showed its cytotoxic effect on CT-26 cells due to its binding to tetranectin and the consequent suppression of the cell proliferation. These results demonstrate that the anticancer effect of epigallocatechin gallate is mediated, at least in part, by inhibiting tetranectin as a binding target.

Analysis of S-glutathionylated proteins during adipocyte differentiation using eosin-glutathione and glutaredoxin 1.

Protein S-glutathionylation is a reversible post-translational modification on cysteine residues forming a mixed disulfide with glutathione. S-glutathionylation, not only protects proteins from oxidation but also regulates the functions of proteins involved in various cellular signaling pathways. In this study, we developed a method for the detection of S-glutathionylated proteins (ProSSG) using eosin-glutathione (E-GSH) and mouse glutaredoxin 1 (mGrx1). ProSSG was efficiently and specifically labeled with E-GSH to form ProSSG-E via thiol-disulfide exchange. ProSSG-E was readily luminescent allowing the detection of ProSSG with semi-quantitative determination. In addition, a deglutathionylation enzyme mGrx1 specifically released E-GSH from ProSSG-E, which increased fluorescence allowing a sensitive determination of ProSSG levels. Application of the method to the adipocyte differentiation of 3T3-L1 cells showed specific detection of ProSSG and its increase upon differentiation induction, which was consistent with the result obtained by conventional immunoblot analysis, but with greater specificity and sensitivity. [BMB Reports 2022; 55(3): 154-159].

Fruit Derived Potentially Bioactive Bioengineered Silver Nanoparticles.

INTRODUCTION: Protein-derived biogenic syntheses of inorganic nanoparticles have gained immense attention because of their broad spectrum of applications. Proteins offer a reducing environment to enable the synthesis of nanoparticles and encapsulate synthesized nanoparticles and provide them temporal stability in addition to biocompatibility. METHODS: In the present study, Benincasa hispida fruit proteins were used to synthesize silver nanoparticles (AgNPs) at 37 °C over five days of incubation. The synthesis of AgNPs was confirmed by UV-Vis spectroscopy, TEM, zeta potential, and DLS analyses. Further, these NPs depicted antibacterial and antibiofilm effects. Additionally, the anticancer activities of nanoparticles were also tested against the lung cancer cell line (A549) with respect to the normal cell line (NRK) using MTT assay. Further, the estimation of ROS generation through DCFH-DA staining along with a reduction in mitochondrial membrane potential by Mito Tracker Red CMX staining was carried out. Moreover, nuclear degradation in the AgNPs treated cells was cross-checked by DAPI staining. RESULTS: The average size of AgNPs was detected to be 27 ±1 nm by TEM analysis, whereas surface encapsulation by protein was determined by FTIR spectroscopy. These NPs were effective against bacterial pathogens such as Escherichia coli, Staphylococcus aureus, Salmonella enteric, and Staphylococcus epidermis with MICs of 148.12 µg/mL, 165.63 µg/mL, 162.77 µg/mL, and 124.88 µg/mL, respectively. Furthermore, these nanoparticles inhibit the formation of biofilms of E. coli, S. aureus, S. enteric, and S. epidermis by 71.14%, 73.89%, 66.66%, and 64.81%, respectively. Similarly, these nanoparticles were also found to inhibit (IC50 = 57.11 µM) the lung cancer cell line (A549). At the same time, they were non-toxic against NRK cells up to a concentration of 200 µM. DISCUSSION: We successfully synthesized potentially potent antibacterial, antibiofilm and anticancer biogenic AgNPs.

Potentially Bioactive Fungus Mediated Silver Nanoparticles.

Fungal metabolites, proteins, and enzymes have been rich sources of therapeutics so far. Therefore, in this study, the hypha extract of a newly identified noble fungus (Alternaria sp. with NCBI Accession number: MT982648) was used to synthesize silver nanoparticles (F-AgNPs) to utilize against bacteria, fungi, and lung cancer. F-AgNPs were characterized by using physical techniques, including UV-visible spectroscopy, zeta potential, DLS, XRD, TEM, and HR-TEM. The particles were found to be polydispersed and quasi-spherical in shape under TEM. They had an average size of ~15 nm. The well dispersed particles were found to have consistent crystallinity with cubic phase geometry under XRD and HR-TEM. The presence of different functional groups on the surfaces of biosynthesized F-AgNPs was confirmed by FTIR. The particle distribution index was found to be 0.447 with a hydrodynamic diameter of ~47 d.nm, and the high value of zeta potential (-20.3 mV) revealed the stability of the nanoemulsion. These particles were found to be active against Staphylococcus aureus (multidrug resistance-MDR), Klebsiella pneumonia, Salmonella abony, and Escherichia coli (MDR) with MIC50 10.3, 12.5, 22.69, and 16.25 µg/mL, respectively. Particles also showed inhibition against fungal strains, including A. flavus, A. niger, T. viridens, and F. oxysporium. Their inhibition of biofilm formation by the same panel of bacteria was also found to be very promising and ranged from 16.66 to 64.81%. F-AgNPs also showed anticancer potential (IC50-21.6 µg/mL) with respect to methotrexate (IC50-17.7 µg/mL) against lung cancer cell line A549, and they did not result in any significant inhibition of the normal cell line BEAS-2. The particles were found to alter the mitochondrial membrane potential, thereby disturbing ATP synthesis and leading to high ROS formation, which are responsible for cell membrane damage and release of LDH, intracellular proteins, lipids, and DNA. A high level of ROS also elicits pro-inflammatory signaling cascades that lead to programmed cell death by either apoptosis or necrosis.

Cisplatin bioconjugated enzymatic GNPs amplify the effect of cisplatin with acquiescence.

Enzymatic gold nanoparticles (B-GNPs) have been synthesized using a natural anticancer agent bromelain (a cysteine protease) and these nanoparticles were used to bioconjugate Cisplatin (highly effective against osteosarcoma and lung cancer). Cisplatin bioconjugated bromelain encapsulated gold nanoparticles (B-C-GNPs) were found profoundly potent against same cancers at much lower concentration with minimum side effects due to the synergistic effect of bromelain. The B-C-GNPs have been observed to inhibit the proliferation of osteosarcoma cell lines Saos-2 and MG-63 with IC50 estimation of 4.51 µg/ml and 3.21 µg/ml, respectively, and against small lung cancer cell line A-549 with IC50 2.5 µg/ml which is lower than IC50 of cisplatin against same cell lines. The B-GNPs/B-C-GNPs were characterized by TEM, UV-Visible spectroscopy, Zeta potential and DLS to confirm the production, purity, crystalline nature, stability of nanoemulsion, size and shape distribution. The change in 2D and 3D conformation of bromelain after encapsulation was studied by Circular Dichroism and Fluorometry, respectively. It was found that after encapsulation, a 19.4% loss in secondary structure was observed, but tertiary structure was not altered significantly and this loss improved the anticancer activity. The confirmation of bioconjugation of cisplatin with B-GNPs was done by UV-Visible spectroscopy, TEM, FTIR, 2D 1H NMR DOSY and ICP-MS. Further, it was found that almost ~4 cisplatin molecules bound with each B-GNPs nanoparticle.

Gold nanoconjugates reinforce the potency of conjugated cisplatin and doxorubicin.

Osteosarcoma or osteogenic sarcoma is the most common and prevalent cancerous tumor of bone and occurs especially in children and teens. Recent treatment strategy includes a combination of both chemotherapy and surgeries. Although, the use of single drug-based chemotherapy treatment remains unsatisfactory. Therefore, combinatorial therapy has emerged as a potential strategy for treatment with limited side- effects. Here, we evaluated the combinatorial anticancerous effect of cisplatin (CIS) and doxorubicin (DOX) bioconjugated bromelain encapsulated gold nanoparticles (B-AuNPs conjugated CIS and DOX) in the treatment of osteosarcoma. The synthesized B-AuNPs conjugated CIS and DOX were characterized by various characterization techniques like UV-vis spectroscopy, TEM, DLS and zeta potential to ensure the synthesis, size, shape, size distribution and stability. Drug loading efficiency bioconjugation of CIS and DOX was ensured by UV-vis spectroscopy. Bioconjugation of CIS and DOX was further confirmed using UV-vis spectroscopy, TEM, DLS, Zeta potential and FT-IR analysis. The combinatorial effect of CIS and DOX in B-AuNPs conjugated CIS and DOX showed highly improved potency against MG-63 and Saos-2 cells at a very low concentration where primary osteoblasts didn't show any cytotoxic effect. The apoptotic effect of B-AuNPs conjugated CIS and DOX on osteosarcoma and primary osteoblasts cells were analyzed by increased permeability of the cell membrane, condensed chromatin and deep blue fluorescent condensed nucleus. The results clearly showed that B-AuNPs conjugated CIS and DOX significantly improved the potency of both the chemotherapeutic drugs by delivering them specifically into the nucleus of cancer cells through caveolae-dependent endocytosis. Thus, the greater inhibitory effect of combinatorial drugs (B-AuNPs conjugated CIS and DOX) over single drug based chemotherapy would be of great advantage during osteosarcoma treatment.

Biogenic terbium oxide nanoparticles as the vanguard against osteosarcoma.

The synthesis of inner transition metal nanoparticles via an ecofriendly route is quite difficult. This study, for the first time, reports synthesis of terbium oxide nanoparticles using fungus, Fusarium oxysporum. The biocompatible terbium oxide nanoparticles (Tb2O3 NPs) were synthesized by incubating Tb4O7 with the biomass of fungus F. oxysporum. Multiple physical characterization techniques, such as UV-visible and photoluminescence spectroscopy, TEM, SAED, and zeta-potential were used to confirm the synthesis, purity, optical and surface characteristics, crystallinity, size, shape, distribution, and stability of the nanoemulsion of Tb2O3 NPs. The Tb2O3 NPs were found to inhibit the propagation of MG-63 and Saos-2 cell-lines (IC50 value of 0.102µg/mL) and remained non-toxic up to a concentration of 0.373µg/mL toward primary osteoblasts. Cell viability decreased in a concentration-dependent manner upon exposure to 10nm Tb2O3 NPs in the concentration range 0.023-0.373µg/mL. Cell toxicity was evaluated by observing changes in cell morphology, cell viability, oxidative stress parameters, and FACS analysis. Morphological examinations of cells revealed cell shrinkage, nuclear condensation, and formation of apoptotic bodies. The level of ROS within the cells-an indicator of oxidative stress was significantly increased. The induction of apoptosis at concentrations ≤IC50 was corroborated by 4',6-diamidino-2-phenylindole dihydrochloride (DAPI) staining (DNA damage and nuclear fragmentation). Flow-cytometric studies indicated that the response was dose dependent with a threshold effect.

Glycation-assisted synthesized gold nanoparticles inhibit growth of bone cancer cells.

This study presents a novel approach to synthesize glycogenic gold nanoparticles (glycogenic GNps) capped with glycated products (Schiff's base, Heyns products, fructosylamine etc.). These glycogenic GNps have been found to be active against human osteosarcoma cell line (Saos-2) with an IC50 of 0.187 mM, while the normal human embryonic lung cell line (L-132) remained unaffected up to 1mM concentration. The size of glycogenic GNps can also be controlled by varying the time of incubation of gold solution. Glycation reactions involving a combination of fructose and HSA (Human Serum Albumin) were found to be effective in the reduction of gold to glycogenic GNps whereas glucose in combination with HSA did not result in the reduction of gold. The progress of the reaction was followed using UV-visible spectroscopy and NBT (Nitroblue tetrazolium) assay. The glycogenic GNps were found to be spherical in shape with an average size of 24.3 nm, in a stable emulsion. These GNps were characterized using UV-visible spectroscopy, zeta potential analysis, transmission electron microscopy (TEM) and scanning electron microscopy (SEM).

Diversity-oriented synthesis of α-aminophosphonates: a new class of potential anticancer agents.

A small library of structurally diverse α-aminophosphonates has been synthesized by reacting alkyl/aryl aldehydes, alkyl/aryl amines and alkyl/aryl phosphites in one-pot catalyzed by Amberlite-IR 120 resin (acidic). All the synthesized α-aminophosphonates were assayed for their in vitro cytotoxic activities against a panel of five human cancer cell lines including A-549, NCI-H23 (Lung), Colo 320DM (Colon), MG-63 (Bone marrow) and Jurkat (Blood T lymphocytes). Compound 4n having (R)-1-phenylethanamine was found to be the most active amongst all the synthesized α-aminophosphonates against all the five cancer cell lines, most prominent being against Jurkat cell line with an IC50 value of 4 µM. Surprisingly, compound 4o having (S)-1-phenylethanamine was found to be devoid of any cytotoxicity. Our finding suggests that these chemical entities could further serve as interesting template for the design of potential anticancer agents.