Human Embryonic Kidney HEK293 Cells Research Articles

Pathogenicity assessment of seven RYR1 variants in patients with confirmed susceptibility to malignant hyperthermia in the Netherlands.

Malignant hyperthermia (MH) susceptibility is associated with variants in RYR1, the gene encoding the skeletal muscle ryanodine receptor-1 (RyR1), in 70-75% of patients. Functional characterisation demonstrating an increased sensitivity to RyR1 agonists is necessary among other criteria for inclusion in the European Malignant Hyperthermia Group list of MH susceptibility diagnostic variants. Seven variants in the RYR1 gene, p.Glu342Lys, p.Leu2288Ser, p.Phe2340Leu, p.Arg2676Trp, p.Val3324Ala, p.Phe4076Leu, and p.Trp5020Cys, identified in MH-susceptible individuals were introduced into the cDNA for the human RYR1 gene. These variants were tested in cultured human embryonic kidney HEK293 cells for their effect on calcium release in response to the RyR1 agonist 4-chloro-m-cresol. Calcium release of each variant was compared with wild-type and benign and pathogenic controls. Each variant was subjected to curation using the European Malignant Hyperthermia Group scoring matrix and ClinGen RYR1 Variant Curation Expert Panel guidelines. Six of seven RYR1 variants (p.Glu342Lys, p.Leu2288Ser, p.Phe2340Leu, p.Arg2676Trp, p.Val3324Ala, p.Phe4076Leu) showed hypersensitivity to 4-chloro-m-cresol compared with wild-type. The p.Trp5020Cys variant did not release calcium in response to 4-chloro-m-cresol. All variants had minor allele frequencies <0.1%. Rare exome variant ensemble learner scores of p.Glu342Lys, p.Leu2288Ser, p.Phe4076Leu, and p.Trp5020Cys were >0.85, supporting pathogenicity. The variants p.Glu342Lys, p.Leu2288Ser p.Phe2340Leu, and p.Arg2676Trp are pathogenic or likely pathogenic for MH and can be used for presymptomatic testing for MH susceptibility. As current knowledge on the p.Val3324Ala, p.Phe4076Leu, and p.Trp5020Cys variants remains insufficient, they are still classified as variants of uncertain significance.

Synthesis, cytotoxicity, apoptosis-inducing activity and molecular docking studies of novel isatin-podophyllotoxin hybrids.

Podophyllotoxin, along with its numerous derivatives and related compounds, is well known for its broad-spectrum pharmacological activity, especially for anticancer potential. In this study, several isatin-podophyllotoxin hybrid compounds were successfully synthesized with good yields through microwave-prompted three-component reactions of 2-amino-1,4-naphthoquinone, various substituted isatins, and tetronic acid. Their cytotoxicity was assessed against four types of human cancer cell lines, HepG2 (hepatoma carcinoma), MCF7 (breast cancer), A549 (non-small lung cancer), and KB (epidermoid carcinoma), alongside nontumorigenic HEK-293 human embryonic kidney cells. Among 14 compounds screened, 7f possessed the strongest cytotoxicity to KB and A549 cell lines, with IC50 values of 1.99 ± 0.22 and 0.90 ± 0.09 μM, respectively. Further studies revealed that product 7f could arrest the cell cycle of A549 cells at S phase and induce apoptosis of A549 cells. This compound was examined for its binding ability against cyclin-dependent kinases (CDKs) and procaspase/caspase systems. The results indicated that 7f exhibited significant interactions with the residues of the ATP binding sites of CDK2/cyclin A and CDK5/p25 and also activated procaspase 6 through stable zinc chelation. Additionally, physicochemical and pharmacokinetic properties related to drug-likeness, in parallel with toxicity, were computationally assessed to identify the main issues that need to be addressed in structural optimization. Taken together, compound 7f was identified as a potent cytotoxic agent that could be considered for anticancer drug discovery and development.

Carbidopa and ZnCarbidopa Induce Reductive Stress in MDA-MB-231 Cells.

The redox imbalance, caused by depletion or generation of reactive oxygen species (ROS), is a key mechanism by which metal complexes exert anticancer effects. Carbidopa has shown the ability to inhibit the MDA-MB-231 cell line, a highly aggressive triple-negative human breast adenocarcinoma, by inducing reductive stress. The metal complex of carbidopa with zinc (ZnCarbi) was designed to modify carbidopa's structure and exhibited increased cytotoxicity against MDA-MB-231 cells. Interestingly, ZnCarbi selectively targets certain cancer cells, showing no impact on the viability of normal HEK293 (human embryonic kidney) cells or other cancer cell lines like A549 (human lung adenocarcinoma), LM3 (murine breast adenocarcinoma), or HCT116 (human colon cancer). Treatment with carbidopa and ZnCarbi induces reductive stress, decreases ROS levels, increases the GSH/GSSG ratio, and protects cells from H2O2-induced death. Both compounds also cause mitochondrial damage, leading to cell death, and exhibit antimetastatic effects by inhibiting cell migration and invasion of MDA-MB-231 cells. Interaction studies with bovine serum albumin showed moderate binding through hydrophobic association. Overall, ZnCarbi demonstrates enhanced anticancer properties compared to carbidopa alone, highlighting its potential as an anticancer and antimetastatic compound.

Mono-N-alkylation of Amphotericin B and Nystatin A1 and Its Amides: Effect on the In Vitro Activity, Cytotoxicity and Permeabilization of Model Membranes.

Objectives: In 2022, the World Health Organization highlighted the necessity for the development of new antifungal agents. Polyene antibiotics are characterized by a low risk of drug resistance; however, their use is limited by low solubility and severe side effects. Methods: A series of N-alkylated derivatives of amphotericin B and nystatin A1 as well as their N-(2-hydroxyethyl)amides were synthesized. Their antifungal activity was evaluated against various Candida strains and Aspergillus fumigatus using the broth microdilution method. Cytotoxicity was assessed using an MTT assay on human embryonic kidney cells HEK293 and human skin fibroblast cells hFB-hTERT6, as well as a hemolysis assay on erythrocytes. Membrane activity was analyzed by fluorimetric measurement of calcein leakage from model liposomes. Results: Derivatives containing the N-(hydroxyethyl)amino)ethyl fragment (compounds 3 and 4) exhibited relatively high antifungal activity, as did N-(2-hydroxyethyl)amides 5 and 9. Bis-modified compounds 6 and 10 did not outperform their mono-modified analogues in terms of activity or cytotoxicity. The mono-N-alkylated compound 3 showed the highest activity/toxicity ratio, which correlated well with its selectivity for ergosterol-containing model membranes. Discussion: Combining two successful modifications does not necessarily improve the activity/toxicity ratio of polyenes. Further studies can be performed for the optimization of carboxyl group of 3.

Functional Interdependence of Anoctamins May Influence Conclusions from Overexpression Studies.

Anoctamin 6 (ANO6, TMEM16F) is a phospholipid (PL) scramblase that moves PLs between both plasma membrane (PM) leaflets and operates as an ion channel. It plays a role in development and is essential for hemostasis, bone mineralization and immune defense. However, ANO6 has also been shown to regulate cellular Ca2+ signaling and PM compartments, thereby controlling the expression of ion channels such as CFTR. Given these pleiotropic effects, we investigated the functional interdependence of the ubiquitous ANO6 with other commonly co-expressed anoctamins. As most expression studies on anoctamins use HEK293 human embryonic kidney cells, we compared ion currents, PL scrambling and Ca2+ signals induced by the overexpression of anoctamins in HEK293 wild-type parental and ANO6-knockout cells. The data suggest that the endogenous expression of ANO6 significantly affects the results obtained from overexpressed anoctamins, particularly after increasing intracellular Ca2+. Thus, a significant interdependence of anoctamins may influence the interpretation of data obtained from the functional analysis of overexpressed anoctamins.

Development and antioxidant evaluation of mango leaf (Mangifera indica L.) extract loaded silk fibroin nanoparticles

The main antioxidant polyphenol compounds in the mango (Mangifera indica L.) leaf extract are susceptible to environmental degradations. Thus, in biomedical applications, the mango leaf extract is commonly encapsulated in a carrier. However, most studies employed the synthetic carrier materials that could affect the human health, and the complicated formulation procedure that could hinder the scalability. Therefore, this work, for the first time, explored the use of silk fibroin (an FDA-approved biomaterial), in nanoparticles platform, to encapsulate and deliver the mango leaf extract, utilizing the simple coacervation preparation method. Initially, the mango leaf ethanolic extract was obtained through maceration, resulting in a total phenolic content of 76.39 ± 0.14 mg GAE/g DPW and a notably high antioxidant activity (IC50 = 6.872 ± 0.512 μg/mL). Subsequently, silk fibroin nanoparticles loaded with the extract were developed by the coacervation technique. Depending on the fibroin content, these nanoparticles exhibited an appropriate size range of 500–800 nm with narrow size distributions, a spherical shape with smooth surfaces, a dominant silk-II crystalline structure, a drug entrapment efficiency exceeding 70%, and retained the main biomarker mangiferin. Moreover, the phenolic-compounds release profiles from the particles followed the three-step process, the first burst-release step, the second sustained-release step, and the third degradation step. The particles were also non-toxic to the erythrocytes and the human embryonic kidney HEK-293 cell line. Lastly, the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay demonstrated that the antioxidant activity of the mango leaf extract was preserved within the extract-loaded nanoparticles. The results suggested that the silk fibroin nanoparticles could be a potential platform to effectively encapsulate and deliver the mango leaf extract for biomedical purposes.

Investigation of Anti-cancer Potential of &lt;i&gt;Solanum virginianum&lt;/i&gt; L. Fruit and Leaf Extracts by &lt;i&gt;In Vitro&lt;/i&gt; and &lt;i&gt;In Silico&lt;/i&gt; Studies

Background: Solanum virginianum L. is used as an ancient medicinal plant in Ayurveda. Aim: The present study aimed to elucidate the anticancer properties of S. virginianum through in vitro and in silico studies. Methods: The plant’s fruits and leaves were subjected to hot extraction using methanol and water as a solvent. The cytotoxicity assay was carried out on MCF-7 (Adenocarcinoma breast cancer cell line) and HEK-293 (Human embryonic kidney cell line—a normal cell line). Cell migration inhibition assay and colony formation assay were performed conform on the MCF-7 cell line. The leaf aqueous extract was subjected to HR-LCMS/MS to evaluate different phytocompounds. The in silico study was performed by checking the binding affinity between NINE-selected phytocompounds and specific apoptotic target proteins. Results: Amongst all extracts, the leaf aqueous extracts showed promising results, as at the 72-h incubation period, the IC50 concentration was 10.4 ± 1.13 μg/mL. Leaf aqueous extract also showed significant results in cell migration inhibition assay and colony-forming assay as compared to fruits. Finding metabolites in aqueous leaf extract was done using HR-LCMS/MS, which revealed the presence of more than 30 phytocompounds. Nine selected phytocompounds were characterized for their ability to bind to specific apoptotic target proteins. Out of the selected compounds docked, ritterazine A showed very strong binding with a binding energy of above -9kcal/mol with all the target proteins. Conclusion: Based on this study, we can conclude that the leaf of S. virginianum has potent anti-cancer activities. Furthermore, there is potential for doing comprehensive research on the therapeutic applications of this plant in breast cancer treatment.

Pharmacological Activation of SIRT3 Modulates the Response of Cancer Cells to Acidic pH.

Cancer cells modulate their metabolism, creating an acidic microenvironment that, in turn, can favor tumor progression and chemotherapy resistance. Tumor cells adopt strategies to survive a drop in extracellular pH (pHe). In the present manuscript, we investigated the contribution of mitochondrial sirtuin 3 (SIRT3) to the adaptation and survival of cancer cells to a low pHe. SIRT3-overexpressing and silenced breast cancer cells MDA-MB-231 and human embryonic kidney HEK293 cells were grown in buffered and unbuffered media at pH 7.4 and 6.8 for different times. mRNA expression of SIRT3 and CAVB, was measured by RT-PCR. Protein expression of SIRT3, CAVB and autophagy proteins was estimated by western blot. SIRT3-CAVB interaction was determined by immunoprecipitation and proximity ligation assays (PLA). Induction of autophagy was studied by western blot and TEM. SIRT3 overexpression increases the survival of both cell lines. Moreover, we demonstrated that SIRT3 controls intracellular pH (pHi) through the regulation of mitochondrial carbonic anhydrase VB (CAVB). Interestingly, we obtained similar results by using MC2791, a new SIRT3 activator. Our results point to the possibility of modulating SIRT3 to decrease the response and resistance of tumor cells to the acidic microenvironment and ameliorate the effectiveness of anticancer therapy.

Propafenone-induced connexin-43 protein accumulation and intracellular dynamics

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): China Scholarship Council Background Connexin-43 (Cx43) plays a pivotal role in intercellular communication through gap junctions. It is instrumental in propagating electrical signals and allowing ions to flow between neighboring cardiomyocytes. This synchronized electrical activity allows the heart to work as a functional syncytium. Any disruption or malfunction of Cx43 can lead to arrhythmias and other cardiac issues. Understanding the functions and regulation of Cx43 is vital in both basic research and clinical contexts. Propafenone, a class Ic antiarrhythmic drug, has shown promise in rhythm control; however, its precise impact on cardiac cellular physiology, particularly regarding Cx43, remains incompletely understood. Purpose To investigate propafenone’s effect on Cx43 expression, physiology, and underlying mechanisms in cell systems. Methods Used cell lines include human embryonic kidney HEK293 cells transfected with Cx43; differentiated murine embryonic carcinoma EPI7 cells with an epithelioid morphology and visceral endoderm-like END2 cells, endogenously expressing high amounts of functional Cx43. Cx43 protein expression levels were determined by Western blot analysis, whereas immunofluorescence (IF) imaged by a Total Internal Reflection Fluorescence (TIRF) microscope was used to assess the subcellular localization of Cx43 proteins. Dye injections were used to gain insight into the effects of propafenone on Cx43 metabolic coupling. Results and Conclusion Full length Cx43 protein levels were increased after treatment with propafenone and IF microscopy showed an intracellular accumulation of Cx43 protein, both on ectopically and endogenously expressed Cx43. Propafenone did not alter Cx43 half-life, in contrast to the lysosomal inhibitor chloroquine. Finally, gap-junctional coupling was decreased by chronic propafenone treatment. We conclude that the class 1c antiarrhythmic drug propanone increases Cx43 protein expression, resulting in its intracellular accumulation, as a side effect.

New piperazine derivatives helvamides B–C from the marine-derived fungus Penicillium velutinum ZK-14 uncovered by OSMAC (One Strain Many Compounds) strategy

Four extracts of the marine-derived fungus Penicillium velutinum J.F.H. Beyma were obtained via metal ions stress conditions based on the OSMAC (One Strain Many Compounds) strategy. Using a combination of modern approaches such as LC/UV, LC/MS and bioactivity data analysis, as well as in silico calculations, influence metal stress factors to change metabolite profiles Penicillium velutinum were analyzed. From the ethyl acetate extract of the P. velutinum were isolated two new piperazine derivatives helvamides B (1) and C (2) together with known saroclazin A (3) (4S,5R,7S)-4,11-dihydroxy-guaia-1(2),9(10)-dien (4). Their structures were established based on spectroscopic methods. The absolute configuration of helvamide B (1) as 2R,5R was determined by a combination of the X-ray analysis and by time-dependent density functional theory (TD-DFT) calculations of electronic circular dichroism (ECD) spectra. The cytotoxic activity of the isolated compounds against human prostate cancer PC-3 and human embryonic kidney HEK-293 cells and growth inhibition activity against yeast-like fungi Candida albicans were assayed.Graphical

Toward Photosynthetic Mammalian Cells through Artificial Endosymbiosis.

Photosynthesis in plants occurs within specialized organelles known as chloroplasts, which are postulated to have originated through endosymbiosis with cyanobacteria. In nature, instances are also observed wherein specific invertebrates engage in symbiotic relationships with photosynthetic bacteria, allowing them to subsist as photoautotrophic organisms over extended durations. Consequently, the concept of engineering artificial endosymbiosis between mammalian cells and cyanobacteria represents a promising avenue for enabling photosynthesis in mammals. The study embarked with the identification of Synechocystis PCC 6803 as a suitable candidate for establishing a long-term endosymbiotic relationship with macrophages. The cyanobacteria internalized by macrophages exhibited the capacity to rescue ATP deficiencies within their host cells under conditions of illumination. Following this discovery, a membrane-coating strategy is developed for the intracellular delivery of cyanobacteria into non-macrophage mammalian cells. This pioneering technique led to the identification of human embryonic kidney cells HEK293 as optimal hosts for achieving sustained endosymbiosis with Synechocystis PCC 6803. The study offers valuable insights that may serve as a reference for the eventual achievement of artificial photosynthesis in mammals.

Antiplatelet activity and toxicity profile of novel phosphonium salts derived from Michael reaction

In this work, five novel phosphonium salts derived from the Michael reaction were screened for their antiplatelet activity. Our findings revealed that compounds 2a, 2b, 2c, and 2d significantly inhibit platelet aggregation triggered by ADP or collagen (P < 0.001). Notably, compound 2c inhibited the arachidonic acid pathway (P < 0.001). Moreover, the selected compounds reduce CD62-P expression and inhibit GPIIb/IIIa activation. The interactions of the active compounds with their targets, ADP and collagen receptors, P2Y12 and GPVI respectively were investigated in silico using molecular docking studies. The results revealed a strong affinity of the active compounds for P2Y12 and GPVI. Additionally, cytotoxicity assays on platelets, erythrocytes, and human embryonic kidney HEK293 cells showed that compounds 2a, 2c and 2d were non-toxic even at high concentrations. In summary, our study shows that phosphonium salts can have strong antiplatelet power and suggests that compounds 2a, 2c and 2d could be promising antiplatelet agents for the management of cardiovascular diseases.

Insights into the characterization and therapeutic potential of Tasar silkworm pupal oil

Oil extracted from various species of silkworm pupae emerged as an alternative source of edible oil with great therapeutic value. However, the Tasar silkworm, is mainly known for producing more textured silk than the applications of its pupal oil. The current study aimed to extract characterize and investigate edible and therapeutic properties of Tasar Pupal Oil (TPO).TPO was extracted by Soxhlet extraction method. Characterization of TPO was conducted by GC/MS and FTIR. The Total phenolic content of TPO was evaluated by Folin-Ciocalteu assay. The safety evaluation of TPO was checked on healthy HEK293 (human embryonic kidney cells) using MTT assay. Whereas, therapeutic properties of TPO were analyzed through DPPH, FRAP, SRB assay and agar-well diffusion method. GC/MS study revealed that α-linolenic acid (ALA) (38%) was the major component of TPO followed by n-hexadecanoic acid (25.64%), and other minor compounds were detected in small amounts. The functional groups of TPO shown by FTIR analysis correspond with similar peaks of edible oils. The TPO was reported to be low in phenolic content. The DPPH and FRAP radical scavenging assays demonstrate that TPO exhibits significant antioxidant capabilities. Further, TPO revealed a substantial dose-dependent anticancer activity against colon cancer cells, with a GI50 value of ≤20 μg/ml. Interestingly, TPO was safe and non-toxic on HEK293 cells. Further, TPO exhibited antibacterial activity against S. typhi and S. mutans at various dilutions. Our findings clearly reveal the potentiality of TPO by displaying the characteristics of edible oil and therapeutic properties including antioxidant, anticancer, and antibacterial.

Interaction and antibacterial activity of ciprofloxacin with choline based ionic liquid and CTAB: A comparative spectroscopic study

In this study, the complexation of potential chemo-therapeutic antibacterial drug, ciprofloxacin (CIP) with varying concentrations of surface active compounds (SACs) i.e., (N-(2-hydroxyethyl)-N,N-dimethyl-1-dodecanaminium bromide (12Cho.Br) and cetyltrimethylammonium bromide (CTAB) has been studied. Multispectroscopic techniques were exploited to carry out the study. The higher binding constant (Kb) value for CIP-CTAB than CIP-12Cho.Br obtained from fluorescence data revealed stronger binding of CTAB than 12Cho.Br, owing to the stronger hydrophobic-hydrophobic interaction betweeen CIP and CTAB compared to CIP and 12Cho.Br. The time resolve fluorescence decay shows changes in average lifetime (τavg) with the increasing concentration of 12Cho.Br and CTAB. The changes in τavg suggests that complex formation is taking place between CIP and 12Cho.Br / CTAB. Further, the formation of micelles by 12Cho.Br / CTAB and the effect of alkyl chain length was studied by dynamic light scattering (DLS) and zeta potential to confirm the drug complexation with 12Cho.Br and CTAB. The antibacterial activity has been performed for CIP and 12Cho.Br and CTAB. It was observed that in presence of lower concentrations of 12Cho.Br/ CTAB, the activity of the drug increased. The activity was also found cationic alkyl chain length dependent. Moreover, in-vitro cytotoxicity of CIP and its combinations with 12Cho.Br and CTAB was performed using MTT assay on HEK293 (Human embryonic kidney cells).

Biooriented Synthesis of Ibuprofen-Clubbed Novel Bis-Schiff Base Derivatives as Potential Hits for Malignant Glioma: In Vitro Anticancer Activity and In Silico Approach.

This research work is based on the synthesis of bis-Schiff base derivatives of the commercially available ibuprofen drug in outstanding yields through multistep reactions. Structures of the synthesized compounds were confirmed by the help of modern spectroscopic techniques including high-resolution electrospray ionization mass spectrometry (HR-ESI-MS), 1H NMR, and 13C NMR. The synthesized compounds were evaluated for their anticancer activity using a normal human embryonic kidney HEK293 cell and U87-malignant glioma (ATCC-HTB-14) as a cancer cell line. All of the synthesized compounds among the series exhibited excellent to less antiproliferative activity having IC50 values ranging from 5.75 ± 0.43 to 150.45 ± 0.20 μM. Among them, compound 5e (IC50 = 5.75 ± 0.43 μM) was found as the most potent antiprolifarative agent, while 5f, 5b, 5a, 5n, 5r, 5s, 5g, 5q, 5i, and 5j exhibited good activity with IC50 values from 24.17 ± 0.46 to 43.71 ± 0.07 μM. These findings suggest that these cells (HEK293) are less cytotoxic to the activities of compounds and increase the cancer cell death in brain, while the lower cytotoxicity of the potent compounds in noncancerous cells suggests that these derivatives will provide promising treatment for patients suffering from brain cancer. The results of the docking study exposed a promising affinity of the active compounds toward casein kinase-2 enzyme, which shows green signal for cancer treatment.

Synthesis and biological evaluation of novel salicylidene uracils: Cytotoxic activity on human cancer cell lines and inhibitory action on enzymatic activity.

A series of salicylidene uracil (1-18) derived from 5-aminouracil and substituted salicylaldehydes were analyzed for cytotoxic activity and enzyme inhibitory potency. Nine out of eighteen derivatives (6-8, 10, 12-15, 18) are novel molecules synthesized for the first time in this work, and other derivatives were previously synthesized by our group. The compounds were characterized by Proton nuclear magnetic resonance, carbon nuclear magnetic resonance, fourier transform infrared spectroscopy, and elemental analysis. All compounds were tested for their in vitro cytotoxicity against PC-3 (human prostate adenocarcinoma), A549 (human alveolar adenocarcinoma), and SHSY-5Y (human neuroblastoma) cancer cell lines and the nontumorigenic HEK293 (human embryonic kidney cells) cell line. The 3,5-di-tert-butylsalicylaldehyde derived compound (8) was toxic to PC-3 human prostate adenocarcinoma cells, showing a promising IC50 value at 7.05 ± 0.76 μM. The present study also aimed to evaluate the inhibitory effects of the compounds against several key enzymes, namely carbonic anhydrase I and II (CA I and CA II), acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and glutathione reductase (GR), which are implicated in various global disorders, such as Alzheimer's disease, epilepsy, cancer, malaria, diabetes, and glaucoma. The inhibitory profiles of the tested compounds were assessed by determining their Ki values, which ranged from 2.96 to 9.24 nM for AChE, 3.78 to 12.57 nM for BChE, 8.42 to 25.74 nM for CA I, 7.24 to 19.74 nM for CA II, and 0.541 to 1.124 μM for GR. Molecular docking studies were also performed for all compounds. Most derivatives exhibited much more effective inhibitory action compared with clinically used standards. Thus, our findings indicate that the salicylidene derivatives presented in this study are promising drug candidates that need further evaluation.

A study on phytochemical composition, antioxidant, and anti-cancer activities of Gingko biloba L.

The study aims to investigate the phytochemical composition, antioxidant potential, and anti-cancer activities of Ginkgo biloba L. leaf methanol extract. In this study, the phytochemical compounds, total phenolic and flavonoid contents of G. biloba leaf methanol extract were investigated. Additionally, antioxidant and anti-cancer activities [against HT-29 (human colon cancer line), HeLa (human cervical cancer line), and HEK-293 (human embryonic kidney cell line)] were assayed. The main phytochemical compounds were identified as gallic (0.94±0.01 mg/g), p-hydroxy benzoic (0.71±0.01 mg/g), and protocatechuic (0.60±0.02 mg/g) acids in G. biloba leaf methanol extract by HPLC. The total phenolic and total flavonoid contents were measured as 71.20±0.42 µg GAE/mg extract and 13.24±0.35 µg QE/mg extract, respectively. The high antioxidant activity was found in ABTS•+ assay (89.04±0.71%) while moderate antioxidant activity was observed in DPPH• (43.31±0.75%), metal chelating (49.04±0.49%), CUPRAC (absorbance: 0.85±0.01), and phosphomolybdenum (absorbance: 1.16±0.02) assays at 400 µg/mL. The IC50 values of G. biloba leaf methanol extract on HT-29, HeLa, and HEK-293 cell lines were recorded as 406.70±1.55, 84.86±0.98, and &gt;800 µg/mL, respectively. The present study features a new addition to the antioxidant and anti-cancer properties of the therapeutically valuable G. biloba with its phytochemical content.

Redox Properties and in Vivo Magnetic Resonance Imaging of Cyclodextrin-Polynitroxides Contrast Agents.

This paper reports the synthesis, characterization and in vivo application of water-soluble supramolecular contrast agents (Mw: 5-5.6 kDa) for MRI obtained from β-cyclodextrin functionalized with different kinds of nitroxide radicals, both with piperidine structure (CD2 and CD3) and with pyrrolidine structure (CD4 and CD5). As to the stability of the radicals in presence of ascorbic acid, CD4 and CD5 have low second order kinetic constants (≤0.05 M-1 s-1 ) compared to CD2 (3.5 M-1 s-1 ) and CD3 (0.73 M-1 s-1 ). Relaxivity (r1 ) measurements on compounds CD3-CD5 were carried out at different magnetic field strength (0.7, 3, 7 and 9.4 T). At 0.7 T, r1 values comprised between 1.5 mM-1 s-1 and 1.9 mM-1 s-1 were found while a significant reduction was observed at higher fields (r1 ≈0.6-0.9 mM-1 s-1 at 9.4 T). Tests in vitro on HEK293 human embryonic kidney cells, L929 mouse fibroblasts and U87 glioblastoma cells indicated that all compounds were non-cytotoxic at concentrations below 1 μmol mL-1 . MRI in vivo was carried out at 9.4 T on glioma-bearing rats using the compounds CD3-CD5. The experiments showed a good lowering of T1 relaxation in tumor with a retention of the contrast for at least 60 mins confirming improved stability also in vivo conditions.

Cytotoxic and apoptotic effects of chemically synthesized silver nanoparticles loaded with recombinant Staphylococcus LukS-PV toxin.

Chronic myeloid leukemia (CML) accounts for approximately 15% of leukemias. LukS-PV, a Panton-Valentine leucocidin (PVL) component, is secreted by Staphylococcus aureus. Silver nanoparticles have increasingly been used for different purposes, most notably for drug delivery and anticancer agents. In this work, the cytotoxicity effect of recombinant LukS-PV protein, chemically synthesized AgNPs, and recombinant LukS-PV protein-loaded silver nanoparticles was investigated on human Chronic myeloid leukemia K562 cells and human normal embryonic kidney HEK293 cells. Cell apoptosis was investigated by staining with Annexin V/propidium iodide. The recombinant LukS-PV protein-loaded silver nanoparticles exhibited dose-dependent cytotoxicity and induced apoptosis in the K562 cells but had little effect on normal HEK293 cells. After 24h of exposure to recombinant LukS-PV protein-loaded silver nanoparticles (IC50 concentration), flow cytometry showed that 31.17% of K562 cells were apoptotic. These results indicate that recombinant LukS-PV protein-loaded silver nanoparticles maybe are a potential chemotherapeutic agent candidate against K562 cells. Hence, silver nanoparticles could be used as drug carriers for toxin release to cancer cells.

Multimerization of HIF enhances transcription of target genes containing the hypoxia ancillary sequence

Transcriptional activity of the hypoxia inducible factor (HIF) relies on the formation of a heterodimer composed of an oxygen-regulated α-subunit and a stably expressed β-subunit. Heterodimeric HIF activates expression by binding to RCGTG motifs within promoters of hypoxia-activated genes. Some hypoxia targets also possess an adjacent HIF ancillary sequence (HAS) reported to increase transcription but whose function remains obscure. Here, we investigate the contribution of the HAS element to the hypoxia response and its mechanism of action, using the HAS-containing prolyl 4-hydroxylase subunit α1 (P4HA1) as a gene model in NIH/3T3 mouse embryonic fibroblasts and HEK293 human embryonic kidney cells. Our HIF overexpression experiments demonstrate that the HAS motif is essential for full induction by hypoxia and that the presence of the tandem HAS/HIF, as opposed to HIF-only sequences, provides HIF proteins with the capacity to form complexes of stoichiometry beyond the classical heterodimer, likely tetramers, to cooperatively potentiate hypoxia-induced transcription. We also provide evidence of the crucial role played by the Fα helix of the PAS-B domain of the HIF1β subunit to support the interaction between heterodimers. Functional analysis showed that human genes containing the HAS/HIF motifs are better responders to hypoxia, and their promoters are enriched for specific transcription factor binding sites. Gene ontology enrichment revealed a predominance of HAS/HIF in genes primarily related to tissue formation and development. Our findings add an extra level of regulation of the hypoxia/HIF signaling through multimerization of HIF proteins on regulatory elements containing the HAS/HIF motifs.