Cell Cytotoxicity Assay Research Articles

Carotenoid containing cationic nanoparticles for effective therapy for suppressing oxidative stress: An intranasal approach

Alzheimer's disease is the most common type of dementia. Oxidative stress is involved in the progression of aging and Alzheimer's disease. It is known that lutein is a carotenoid having antioxidant properties. The present research explores Lutein loaded chitosan nanoparticles for Suppressing Oxidative Stress in the treatment of Alzheimer's. The developed nanoparticles are administered through the nose to target brain via nose-to-brain pathway. For optimization of formulation a systematic QbD approach was used. The developed nanoparticles further characterized for Physicochemical parameters, Morphology, In-vitro drug releases, Ex-vivo diffusion, In-vitro Cell viability, cellular uptake, In-vitro BBB Permeation, antioxidant properties, In-vivo biodistribution, and stability study. The developed nanoparticles' surface morphology suggested homogeneously dispersed spherical nanoparticles having < 200 nm size. The drug release study demonstrate the controlled release of lutein for more than 96 h while less than 50% lutein was released after 24 h in an ex-vivo diffusion study. The cell cytotoxicity assay confirms the nontoxicity of l-CNPs. The cellular uptake study shows enhanced internalization of l-CNPs through the caveolae-mediated endocytosis pathway. The ROS generation confirmed the absence of any significant ROS generation nanoparticles. The antioxidant assay shows significant ROS scavenging activity of l-CNPs. In-vitro BBB permeation demonstrates the efficient passage of l-CNPs through BBB compared to pure lutein. This was further supported by bio-distribution demonstrating the deposition of nanoparticles in the brain through nasal administration. The acquired outcomes prove the possible activities of lutein-loaded l-CNPs for reducing oxidative stress in the brain for Alzheimer's treatment.

Regulating tumor microenvironments by a lymph node-targeting adjuvant via tumor-specific CTL-derived IFNγ

Inducing tumor-specific T cell responses and regulating suppressive tumor microenvironments have been a challenge for effective tumor therapy. CpG (ODN), the Toll-like receptor 9 agonist, has been widely used as adjuvants of cancer vaccines to induce T cell responses. We developed a novel adjuvant to improve the targeting of lymph nodes. CpG were modified with lipid and glycopolymers by the combination of photo-induced RAFT polymerization and click chemistry, and the novel adjuvant was termed as lipid-glycoadjuvant@AuNPs (LCpG). OVA protein was used as model antigen and melanoma model was established to test the immunotherapy effect of the adjuvant. In tumor model, the antitumor effect and mechanism of LCpG on the response of CTLs were examined by flow cytometry and cell cytotoxicity assay. The effects of LCpG on macrophage polarization and Tregs differentiation in tumor microenvironment were also studied by cell depletion assay and cytokine neutralization assay. We also tested the therapeutic effect of the combination of the adjuvant and anti-PD-1 treatment. LCpG could be rapidly transported to and retained longer in the lymphoid nodes than unmodified CpG. In melanoma model, LCpG controlled both primary tumor and its metastasis, and established long-term memory. In spleen and tumor draining lymphoid nodes, LCpG activated tumor-specific Tc1 responses, with increased CD8+ T-cell proliferation, antigen–specific Tc1 cytokine production and specific-tumor killing capacity. In tumor microenvironments, antigen-specific Tc1 induced by the LCpG promoted CTL infiltration, skewed tumor associated macrophages to M1 phenotype, regulated Treg and induced proinflammatory cytokines production in a CTL-derived IFN-γ-dependent manner. In vivo cell depletion and adoptive transfer experiments confirmed that antitumor activity of LCpG included vaccine was mainly dependent on CTL-derived IFN-γ. The anti-tumor efficacy of LCpG was dramatically enhanced when combined with anti-PD1 immunotherapy. LCpG was a promising adjuvant for vaccine formulation which could augment tumor-specific Tc1 activity, and regulate tumor microenvironments.

Targeting the monocarboxylate transporter MCT2 and lactate dehydrogenase A LDHA in cancer cells with FX-11 and AR-C155858 inhibitors.

In 1930, Otto Warburg reported that "aerobic glycolysis" is the intrinsic property of all tumor cells' fermentation of glucose to L-Lactate by lactate dehydrogenase A (LDHA) activity. This only produces per mole of glucose two moles of adenosine triphosphate (ATP), compared with 32 moles of ATP in a normal cell. Thus, tumor cells have to uptake 30 folds more glucose, the resulting accumulated lactate are then transported by a monocarboxylate transporter (MCT) with the participation of a CD147 molecule. Inhibition of MCT1 by RNA interference (RNAi) disrupted the unique metabolism of the tumor and caused tumor cell death. However, the effectiveness of the strategies depends on the targeted delivery of the therapeutics. In this study, a synergistic approach was used to target LDHA and MCT1 with small molecule inhibitors FX11 and AR-C155858, respectively. Cell cytotoxicity assays (AlamarBlue assay), and Mitochondria Membrane Potential (JC-1) dye assays were performed on human breast cancer cells MCF-7 and colorectal cancer cells HCT116. To achieve this aim, the following objectives were proposed: the effect of metabolic inhibitors on tumor glycolytic metabolite environment, and the efficacy of metabolite inhibitors on human breast and colorectal cancer cells in vitro. Then, gene expression analysis was performed using Qiagen RT2 Profiler PCR array for apoptosis. All these assays were performed on human breast cancer cells MCF-7 and colorectal cancer cells HCT116. Normal human fibroblasts were used as control cells under normal and hypoxic culture conditions. In this study, the use of FX-11 inhibitors under normoxia or hypoxia in two or more cancer and normal cell lines has a direct effect on LDHA, whereby it inhibits its production, and this reduces the growth and cell proliferation of tumors. One of the more significant findings to emerge from this study is that using AR-C155858 inhibitor alone has increased the cell proliferation and showed no significant changes compared with the control. The other major finding was that combination of the two inhibitors, FX-11 and AR-C155858, under normoxia or hypoxia in two different cell lines MCF-7 and HCT-116 measured a decrease in the cells proliferative and red/green ratio. We successfully demonstrated that a combination of MCT1 inhibitor and LDHA inhibitor led to better outcomes. Indeed, this makes LDHA an ideal metabolic therapeutic target.

New Ligand-Based Metal Complexes: Synthesis, Spectroscopic Characterization, Thermal Behavior, Anticancer Properties, and Biological Activity

New ligands, N1, N4-bis (benzo[d]thiazol-2- ylcarbamothioyl) succinamide (L1) and N1, N4- bis (benzylcarbamothioyl)succinamide (L2), derived from succinyl chloride and 2-amino benzothiazole or benzylamine, respectively, have been used to prepare a set of transition metal complexes with the general formula [M2(L)Cl4], where L=L1 or L2, M = Mn(II), Ni(II), Cu(II), Cd(II), Co(II), Zn(II) or Hg(II). The synthesized compounds were characterized using various analytical techniques including TGA, 13C NMR, mass spectroscopy, 1H and Fourier-transform infrared (FTIR) spectroscopy, magnetic measurement, molar conductivity, electronic spectrum, (%M, %C, %H, %N) and atomic absorption flame (AAF) analysis. The results showed that (L1, L2) bind to the metal ion in a bidentate fashion through the (C=O) and (C=S) groups, and the complexes have a tetrahedral geometry. The antibacterial activity of the compounds was tested against two types of bacteria, Escherichia coli (−) and Staphylococcus aureus (+). Additionally, the anticancer activity of the Cu(II) and Co(II) complexes was evaluated by carrying out cell viability and cytotoxicity assays on the MCF-7 breast cancer cell line and comparing the results with those obtained for normal cells.

Functionalized europium-doped hollow mesoporous silica nanospheres as a cell imaging and drug delivery agents

In an effort to enhance the antitumor efficacy of breast cancer treatment, the chemotherapeutic agent Paclitaxel (PTX) was encapsulated within hyaluronic acid (HA) modified hollow mesoporous silica (HMSNs). In vitro drug release assays showed that the resulting formulation, Eu-HMSNs-HA-PTX, exhibited enzyme-responsive drug release. In addition, cell cytotoxicity and hemolysis assays demonstrated the favorable biocompatibility of both Eu-HMSNs and Eu-HMSNs-HA. Notably, compared to Eu-HMSNs alone, Eu-HMSNs-HA showed enhanced accumulation within CD44-expressing cancer cells (MDA-MB-231). As anticipated, apoptosis experiments indicated that Eu-HMSNs-HA-PTX displayed significantly greater cytotoxicity toward MDA-MB-231 cells than non-targeted Eu-HMSNs-PTX and free PTX. In conclusion, Eu-HMSNs-HA-PTX demonstrated excellent anticancer effects and holds promise as a potent candidate for the efficient therapy of breast cancer.

Dalbergia sissoo phytochemicals as EGFR inhibitors: an in vitro and in silico approach

The safest and most effective sources of medications are natural and traditional medicines derived from plants and herbs. In Western India, various parts of the Dalbergia sissoo plant, which belongs to the Fabaceae family, have been traditionally used to treat different types of cancer by the local tribes. However, this claim has not been scientifically proven yet. Thus, the purpose of this study was to examine the antioxidant (2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity) and anticancer effects of different plant extracts from Dalbergia sissoo bark, root, and branch on six different cancer cell lines (K562, PC3, A431, A549, NCIH 460, and HEK 293 T) using in vitro cell viability and cytotoxicity assays. The study also involved in silico docking, MD simulation, and ADME studies of previously reported bioactive compounds from the same parts of the plant to confirm their bioactivity. The DPPH radical scavenging experiment findings showed that the methanol: water extract of the bark had a more significant antioxidant activity IC50 (45.63 ± 1.24 mg/mL). Furthermore, the extract prevented the growth of the A431, A549, and NCIH 460 cancer cell lines with the lowest IC50 values of 15.37, 29.09, and 17.02 g/mL, respectively, demonstrating remarkable anticancer potential. Molecular docking and dynamic simulation studies revealed that Prunetin, Tectorigenin, and Prunetin 4'-O-Galactoside show efficient binding to the EGFR binding domain. This study suggests that tested hits may have antioxidant and anticancer agents and can be considered for future applications in the pharma sector. Communicated by Ramaswamy H. Sarma

Prognostic impact of peripheral natural killer cells in primary central nervous system lymphoma.

Primary central nervous system lymphoma (PCNSL) is an aggressive extranodal non-Hodgkin lymphoma with a poor prognosis. We aimed to evaluate the prognostic impact of circulating NK cells in PCNSL. Patients diagnosed with PCNSL who were treated at our institution between December 2018 and December 2019 were retrospectively screened. Patient variables including age, sex, Karnofsky performance status, diagnostic methods, location of lesions, lactate dehydrogenase, cerebrospinal fluids (CSF), and vitreous fluids involvement or not were documented. NK cell count and NK cell proportion (NK cell count/lymphocyte count) in the peripheral blood were evaluated by flow cytometry. Some patients underwent two consecutive NK cell tests before and three weeks after chemotherapy (before the next chemotherapy). The fold change in NK cell proportion and NK cell counts were calculated. CD56-positive NK cells in tumor tissue were assessed by immunohistochemistry. NK cell cytotoxicity assay was performed using flow cytometry. A total of 161 patients with PCNSL were included in this study. The median NK cell count of all NK cell tests was 197.73/μL (range 13.11-1889.90 cells/μL). The median proportion of NK cells was 14.11% (range 1.68-45.15%) for all. Responders had a higher median NK cell count (p<0.0001) and NK cell proportion (p<0.0001) than non-responders. Furthermore, Responders had a higher median fold change in NK cell proportion than non-responders (p=0.019) or patients in complete remission/partial remission (p<0.0001). A higher median fold change in NK cell count was observed in responders than in non-responders (p=0.0224) or patients in complete remission/partial remission (p=0.0002). For newly diagnosed PCNSL, patients with a high NK cell count (>165 cells/μL) appeared to have a longer median overall survival than those with a low NK cell count (p=0.0054). A high fold change in the proportion of NK cells (>0.1957; p=0.0367) or NK cell count (>0.1045; p=0.0356) was associated with longer progression-free survival. Circulating NK cells from newly-diagnosed PCNSL demonstrated an impaired cytotoxicity capacity compared to those from patients with PCNSL in complete remission or healthy donors. Our study indicated that circulating NK cells had some impact on the outcome of PCNSL.

Emergence of ST463 exoU-Positive, Imipenem-Nonsusceptible Pseudomonas aeruginosa Isolates in China.

This study investigated the resistance mechanisms and the distribution and proportions of virulence genes, including exoU, in 182 imipenem-nonsusceptible Pseudomonas aeruginosa (INS-PA) strains collected from China in 2019. There was no obvious prevalent sequence type or concentrated evolutionary multilocus sequence typing (MLST) type on the INS-PA phylogenetic tree in China. All of the INS-PA isolates harbored β-lactamases with/without other antimicrobial mechanisms, such as gross disruption of oprD and overexpression of efflux genes. Compared with exoU-negative isolates, exoU-positive isolates (25.3%, 46/182) presented higher virulence in A549 cell cytotoxicity assays. The southeast region of China had the highest proportion (52.2%, 24/46) of exoU-positive strains. The most frequent exoU-positive strains belonged to sequence type 463 (ST463) (23.9%, 11/46) and presented multiple resistance mechanisms and higher virulence in the Galleria mellonella infection model. The complex resistance mechanisms in INS-PA and the emergence of ST463 exoU-positive, multidrug-resistant P. aeruginosa strains in southeast China indicated a challenge that might lead to clinical treatment failure and higher mortality. IMPORTANCE This study investigates the resistance mechanisms and distribution and proportions of virulence genes of imipenem-nonsusceptible Pseudomonas aeruginosa (INS-PA) isolates in China in 2019. Harboring PDC and OXA-50-like genes is discovered as the most prevalent resistance mechanism in INS-PA, and the virulence of exoU-positive INS-PA isolates was significantly higher than that of exoU-negative INS-PA isolates. There was an emergence of ST463 exoU-positive INS-PA isolates in Zhejiang, China, most of which presented multidrug resistance and hypervirulence.

Lactate-induced lactylation circularly regulates glucose metabolism enzymes in breast cancer.

e13092 Background: Breast cancer is the most common malignant tumor in the female population worldwide and has become the disease with the highest cancer-related mortality. Among the molecular subtypes of breast cancer, triple-negative breast cancer accounts for only 15% of primary malignancies, but due to its increasing recurrence, metastasis, and mortality, we need to find new therapeutic targets to address this phenomenon. Analysis from the field of metabolism found that the level of glycolysis in triple-negative breast cancer was significantly higher than that in other cancers. Glycolysis is a common malignant phenotype of cancer, namely the famous Warburg effect. LDHA is the last metabolic enzyme in the glycolytic pathway, and its expression is increased in triple-negative breast cancer. Lactate is the final product of glycolysis, which converts pyruvate to lactate and NADH to NAD+ under the catalysis of LDHA. The acidic tumor microenvironment formed by the accumulation of lactate will not only affect the progression of tumors and the therapeutic effect of anticancer drugs, but also inhibit the function of immune cells. Lactic acid groups can bind to histones and non-histone proteins to produce a new post-translational modification, lactylation. Methods: Breast cancer cells were infected with lentivirus vectors overexpressing or knocking down LDHA, and cell proliferation and cytotoxicity assay, transwell assay and Lactic Acid Content Assay were performed. To further explore the presence of lactylation of LDHA, immunoprecipitation experiments were performed and the modification sites were mutated to examine the enzymatic activity and function of LDHA. Results: In triple negative breast cancer with strong glycolytic metabolic phenotype, altering LDHA level can affect the biological function of breast cancer cells. Secondly, RNA-seq sequencing results showed that LDHA can affect the protein and transcription levels of MEST and CSTA. Finally, the lactylation of histones was also significantly changed after LDHA dysregulated. Reduced levels of LDHA were accompanied by reduced levels of MEST, CSTA, and histone lactylation. In addition, LDHA itself also has lactic acid modification, and mutations in the modification sites can change the enzymatic activity and function of LDHA. Conclusions: The regulatory axis of LDHA-lactate-lactylation has important value and function in the occurrence and development of breast cancer. LDHA regulates the function of some genes by lactate-induced lactylation of histones. In addition, the lactylation of LDHA can alter the enzyme activity, which may be a new therapeutic target for breast cancer.

Evaluation of physicochemical properties, release kinetics, and in vitro/in vivo wound healing activity of the electrospun nanofibres loaded with the natural antioxidant oil from Pistacia atlantica

Herbal medicine is an extraordinary source of bioactive compounds, and developing them can aid in the wound healing process. This study focuses on the optimal production of nanofibres containing an effective herbal extract. The nanofibres were produced by electrospinning a polymer solution containing polyvinyl alcohol (PVA) and sodium alginate (ALG) with Pistacia atlantica oil (PAO) (0, 1.5%, and 2.5% (w/v)). The PAO is rich in different biological properties including antioxidant, anti-inflammatory and antibacterial activities. The addition of 1.5% (w/v) PAO to PVA/ALG solutions increased surface tension and conductivity by 3.5% and 3.86%, respectively. Besides, the scanning electron microscopy (SEM) images revealed that the diameter of the nanofibres increased from 191 nm ± 15 nm–259 nm ± 10 nm. According to differential scanning calorimetry (DSC) results, the nanofibres loaded with 1.5% (w/v) PAO exhibited higher thermal stability compared to PVA/ALG nanofibres without PAO. Based on the in vitro drug release experiments, the PAO release from nanofibres followed the Korsmeyer-Peppas model and the pseudo-Fickian mechanism. Cell culture and cytotoxicity assay results illustrated that the PAO-loaded nanofibres had non-cytotoxic effects against L-929 cells with suitable fibroblast cell proliferation and cell viability. Animal test results showed that the PAO-loaded nanofibres significantly enhanced wound closure by 92.07% compared to PAO-unloaded nanofibres (p < 0.02). The wound healing ability of PAO was also confirmed by the histopathological findings, with PAO increasing re-epithelization and successfully attenuating tissue inflammation. Overall, this study introduces a new type of wound dressing containing PAO, a wound healing stimulant with excellent properties such as uniform structure, antibacterial activity, and breathability. Consequently, the results suggest that the investigated nanofibres may merit being considered as an ideal wound dressing for future clinical investigations into wound therapy and regeneration.

Alginate-based ‘nano-micro’ hybrid matrices developed using ultrasonic atomization for Co-delivery of chemotherapeutic drugs against superficial tumors

Cancer has remained a life-threatening condition, with about 9.6 million deaths globally, despite the advancements and research in therapeutic approaches. Several chemotherapeutic agents are available which can reduce the size of tumors but have non-specific adverse effects on surrounding cells and the propensity to cause the formation of multi-drug resistant tumors. This report investigates a novel and facile method of ultrasonic atomization for the synthesis of Doxorubicin (Dox) loaded chitosan and Piperine (Pip) loaded Poly lactide-co-glycolide (PLGA) nanoparticles (Dox-Ch-NP, Pip-PLGA-NP). Further co-encapsulate these drug-loaded nanoparticles in hybrid alginate microspheres (HAM) using the same technique. The nanoparticles and microspheres were analyzed for size and morphology by DLS, SEM, TEM and CLSM. In vitro studies were performed to determine encapsulation efficiency, drug release and cell cytotoxicity. For the in-vivo evaluation of this co-delivery vehicle Swiss Albino Mice were used. The ultrasonic atomization process led to the development of Dox-Ch-NP (50–150 nm), Pip-PLGA-NP (50–200 nm) and HAM (5 μm). The encapsulation efficiency was 32% and 67% in the case of Dox-Ch-NP and Pip-PLGA-NP, respectively. Sustained in vitro release of both drugs was achieved for 15 days. MTT-based cell cytotoxicity assay shows 88% cell viability in HEK-293 and 51% in HeLa cells after 24Hrs of treatment with HAM. The in-vivo study suggested 93% of tumor reduction with Dox-Ch-NP treatment, 75% reduction with Pip-PLGA-NP treatment While 100% reduction in tumor volume after 15 days of treatment completion. The in-vivo study also showed higher and faster tumor volume reduction in co-delivered drugs via HAM than in single drug-loaded nanoparticles. The results indicate the successful formulation of multi-drug hybrid carriers which can aid in generating an efficient anti-tumor therapeutic regimen for localized tumors with reduced chances of occurrence of multi-drug resistant tumors.

Preparation of biomolecules-mimic poly (ether sulfone)-based hydrogels and their anti-thrombotic, endothelialization and anti-microbial properties

The development of novel hydrogels with high biocompatibility is a vital and active topic of study. Here, we used a facile polycondensation approach to develop multifunctional poly (ether sulfone) (PES)-based hydrogels with diverse functional groups (−SO3Na, −COONa, −OH, and − NH2), as indicated by flourier transformed infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The chemical structure of the PES-based hydrogels could be modulated by monomer selection and post-treatment, resulting in a wide range of biomolecule-mimic structures and matching biological functions. In the current investigation, heparin-mimic PES-based hydrogels demonstrated good hemocompatibility, as evident by reduced platelet adhesion and activation, delayed clotting times, suppressed blood-related complement activations, and CD11b expression on leukocytes in the blood. Moreover, hyper-sulfonated PES-based hydrogels showed exceptional cytocompatibility with human umbilical vein endothelial cells (HUVECs) and considerable antiproliferative activity against human umbilical artery smooth muscle cells (HUASMCs), as revealed by cell proliferation and cytotoxicity assay findings. Finally, chitosan-mimic PES-based hydrogels had marked anti-microbial properties against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), as shown by the number of colonies. The aforementioned bio-functions were attributed to the formation of various chemical structures on the surfaces of PES-based hydrogels. The distinctive PES-based hydrogels synthesized in this work would be of high utility not only in the synthesis of biomedical hydrogels but also in the rational design of various types of biocompatible materials.

Effects of metformin on human gingival fibroblasts: an in vitro study

ObjectiveTo investigate the effects of metformin (MF) treatment on the matrix metalloproteinases (MMPs) and proinflammatory cytokines production from lipopolysaccharide (LPS) - stimulated human gingival fibroblasts (HGFs).MethodsHGFs were obtained from subcultures of biopsies from clinically healthy gingival tissues of patients undergoing oral surgeries. Cell cytotoxicity assay was used to determine the effect of different concentrations of MF on viability of HGFs. HGFs were then incubated and treated with different concentrations of MF and Porphyromonas gingivais (Pg) LPS. MMP-1, MMP-2, MMP-8, MMP-9, IL-1β, and IL-8 expression analysis was performed using xMAP technology (Luminex 200, Luminex, Austin, TX, USA). Student’s t-test for a single sample was used to compare the mean values of the study groups with the control value. A p-value of <0.05 and 95% confidence intervals were used to report the statistical significance and precision of mean values.ResultsConcentrations of 0.5, 1- and 2-mM MF had a minimal non-significant cytotoxic effect on the HGFs and caused statistically significant reduction of MMP-1, MMP-2, MMP-8 and IL-8 expressed by the LPS-stimulated HGFs.ConclusionThe results of the present study confirm that MF suppresses MMP-1, MMP-2, MMP-8 and IL-8 in LPS-stimulated HGFs suggesting an anti-inflammatory effect of MF and potential adjunct therapeutic role in the treatment of periodontal diseases.

Novel Pyrimidine Derivatives as Antioxidant and Anticancer Agents: Design, Synthesis and Molecular Modeling Studies.

The heterocyclic ring system of pyrido [2,3-d]pyrimidines is a privileged scaffold in medicinal chemistry, possessing several biological activities. The synthesis of the pyrimidine derivatives was performed via the condensation of a suitable α,β-unsaturated ketone with 4-amino-6-hydroxy-2-mercaptopyrimidine monohydrate in glacial acetic acid. Chalcones were synthesized, as starting materials, via the Claisen-Schmidt condensation of an appropriately substituted ketone and an appropriately substituted aldehyde in the presence of aqueous KOH 40% w/v in ethanol. All the synthesized compounds were characterized using IR, 1H-NMR, 13C-NMR, LC-MS and elemental analysis. The synthesized compounds were evaluated for their antioxidant (DPPH assay), anti-lipid peroxidation (AAPH), anti-LOX activities and ability to interact with glutathione. The compounds do not interact significantly with DPPH but strongly inhibit lipid peroxidation. Pyrimidine derivatives 2a (IC50 = 42 μΜ), 2f (IC50 = 47.5 μΜ) and chalcone 1g (IC50 = 17 μM) were the most potent lipoxygenase inhibitors. All the tested compounds were found to interact with glutathione, apart from 1h. Cell viability and cytotoxicity assays were performed with the HaCaT and A549 cell lines, respectively. In the MTT assay towards the HaCaT cell line, none of the compounds presented viability at 100 μM. On the contrary, in the MTT assay towards the A549 cell line, the tested compounds showed strong cytotoxicity at 100 μM, with derivative 2d presenting the strongest cytotoxic effects at the concentration of 50 μΜ.

Involvement of the excretory/secretory and surface-associated antigens of Dirofilaria immitis adult worms in the angiogenic response in an in-vitro endothelial cell model

Angiogenesis is a process by which new vessels are formed from pre-existing ones when the physiological conditions of the vascular endothelium are altered. Heartworm disease, caused by Dirofilaria immitis, causes changes in the vascular endothelium of the pulmonary arteries due to obstruction, friction, and hypoxia. The aim of this study was to analyze whether the excretory/secretory and surface-associated antigens of adult worms interact and modulates the angiogenic mechanism, viable cell number and cell migration, as well as the formation of pseudo-capillaries. Cultures of human vascular endothelial cells (HUVECs) stimulated with excretory/secretory antigens (DiES), surface-associated antigens (Cut) from D. immitis adult worms, VEFG-A (Vascular Endothelial Growth Factor A), as well as DiES+VEFG-A and Cut+VEFG-A were used. The production of VEFG-A and other proangiogenic [soluble VEFGR-2 (sVEFGR-2), membrane Endoglin (mEndoglin)] and antiangiogenic [VEFGR-1/soluble Flt (sFlt), soluble Endoglin (sEndoglin)] molecules was assessed using commercial ELISA kits. Cell viability was analyzed by live cell count and cytotoxicity assays by a commercial kit. In addition, viable cell number by MTT-based assay, cell migration by wound-healing assay carrying out scratched wounds, and the capacity of pseudo-capillary formation to analyze cell connections and cell groups in Matrigel cell cultures, were evaluated. In all cases, non‑stimulated cultures were used as controls. DiES+VEFG-A and Cut+VEFG-A significantly increased the production of VEFG-A and sVEFGR-2, and only Cut+VEFG-A significantly increased the production of VEFGR-1/sFlt compared to other groups and non-stimulated cultures. Moreover, only DiES+VEFG-A produced a significant increase in viable cell number and significant decrease cell migration, as well as in the organization and number of cell connections. Excretory/secretory and surface-associated antigens of adult D. immitis activated the angiogenic mechanism by mainly stimulating the synthesis of proangiogenic factors, and only excretory/secretory antigens increased viable cell number, activated cell migration and the formation of pseudo-capillaries. These processes could lead to vascular endothelial remodeling of the infected host and favor the long-term survival of the parasite.

Esterase Specific Fluorescent Probe: Mechanistic Understanding Using QM/MM Calculation and Cell States Discrimination.

Esterases enzymes regulate the body's homeostasis by catalyzing the hydrolysis of various esters. These are also involved in protein metabolism, detoxification, and signal transmission. Most importantly, esterase plays a significant role in cell viability and cytotoxicity assays. Hence, developing an efficient chemical probe is essential for monitoring the esterase activity. Several fluorescent probes for esterase have also been reported targeting cytosol and lysosomes. However, the ability to create efficient probes is constrained due to a lack of understanding of the esterase's active site for hydrolyzing the substrate. In addition, the fluorescent turn-on may limit efficient monitoring. Herein, we have developed a unique fluorescent probe, PM-OAc, to monitor mitochondrial esterase enzyme activity ratiometrically. This probe exhibited a bathochromic wavelength shift with esterase enzyme in alkaline pH (pH∼8.0) due to an intramolecular charge transfer (ICT) process. The phenomenon is well supported by TD-DFT calculation. Moreover, the substrate (PM-OAc) binding at the active site of esterase and its catalytic mechanism to hydrolyze the ester bond are elucidated by molecular dynamics (MD) simulation and QM/MM (Quantum mechanics/molecular mechanics) calculations, respectively. Fluorescent image-based analysis of the cellular environment reveals that our probe can distinguish between live and dead cells based on esterase enzyme activity.

Assessing Acanthamoeba cytotoxicity: comparison of common cell viability assays.

In vitro models for studying interactions between Acanthamoeba and host cells are crucial for understanding the pathomechanism of Acanthamoeba and assessing differences between strains and cell types. The virulence of Acanthamoeba strains is usually assessed and monitored by using cell cytotoxicity assays. The aim of the present study was to evaluate and compare the most widely used cytotoxicity assays for their suitability to assess Acanthamoeba cytopathogenicity. The viability of human corneal epithelial cells (HCECs) after co-culture with Acanthamoeba was evaluated in phase contrast microscopy. It was shown that Acanthamoeba is unable to considerably reduce the tetrazolium salt and the NanoLuc® Luciferase prosubstrate to formazan and the luciferase substrate, respectively. This incapacity helped to generate a cell density-dependent signal allowing to accurately quantify Acanthamoeba cytotoxicity. The lactate dehydrogenase (LDH) assay led to an underestimation of the cytotoxic effect of Acanthamoeba on HCECs since their co-incubation negatively affected the lactate dehydrogenase activity. Our findings demonstrate that cell-based assays using the aqueous soluble tetrazolium-formazan, and the NanoLuc® Luciferase prosubstrate products, in contrast to LDH, are excellent markers to monitor the interaction of Acanthamoeba with human cell lines and to determine and quantify effectively the cytotoxic effect induced by the amoebae. Furthermore, our data indicate that protease activity may have an impact on the outcome and thus the reliability of these tests.

Modulatory role of copper on hIAPP aggregation and toxicity in presence of insulin

Aggregation of the human islets amyloid polypeptide, or hIAPP, is linked to β-cell death in type II diabetes mellitus (T2DM). Different pancreatic β-cell environmental variables such as pH, insulin and metal ions play a key role in controlling the hIAPP aggregation. Since insulin and hIAPP are co-secreted, it is known from numerous studies that insulin suppresses hIAPP fibrillation by preventing the initial dimerization process. On the other hand, zinc and copper each have an inhibitory impact on hIAPP fibrillation, but copper promotes the production of toxic oligomers. Interestingly, the insulin oligomeric equilibrium is controlled by the concentration of zinc ions when the effect of insulin and zinc has been tested together. Lower zinc concentrations cause the equilibrium to shift towards the monomer and dimer states of insulin, which bind to monomeric hIAPP and stop it from developing into a fibril. On the other hand, the combined effects of copper and insulin have not yet been studied. In this study, we have demonstrated how the presence of copper affects hIAPP aggregation and the toxicity of the resultant conformers with or without insulin. For this purpose, we have used a set of biophysical techniques, including NMR, fluorescence, CD etc., in combination with AFM and cell cytotoxicity assay. In the presence and/or absence of insulin, copper induces hIAPP to form structurally distinct stable toxic oligomers, deterring the fibrillation process. More specifically, the oligomers generated in the presence of insulin have slightly higher toxicity than those formed in the absence of insulin. This research will increase our understanding of the combined modulatory effect of two β-cell environmental factors on hIAPP aggregation.

Selected Gut Bacteria from Water Monitor Lizard Exhibit Effects against Pathogenic Acanthamoeba castellanii Belonging to the T4 Genotype.

Water monitor lizards (WMLs) reside in unhygienic and challenging ecological surroundings and are routinely exposed to various pathogenic microorganisms. It is possible that their gut microbiota produces substances to counter microbial infections. Here we determine whether selected gut bacteria of water monitor lizards (WMLs) possess anti-amoebic properties using Acanthamoeba castellanii of the T4 genotype. Conditioned media (CM) were prepared from bacteria isolated from WML. The CM were tested using amoebicidal, adhesion, encystation, excystation, cell cytotoxicity and amoeba-mediated host cell cytotoxicity assays in vitro. Amoebicidal assays revealed that CM exhibited anti-amoebic effects. CM inhibited both excystation and encystation in A. castellanii. CM inhibited amoebae binding to and cytotoxicity of host cells. In contrast, CM alone showed limited toxic effects against human cells in vitro. Mass spectrometry revealed several antimicrobials, anticancer, neurotransmitters, anti-depressant and other metabolites with biological functions. Overall, these findings imply that bacteria from unusual places, such as WML gut, produce molecules with anti-acanthamoebic capabilities.

Abstract 913: Engineering allogeneic off-the-shelf CD19-directed CAR-iNKT cells without additional genetic manipulations for the treatment of hematological malignancies

Abstract Despite the approval of three autologous CAR-T cell products, B-cell malignancies still represent an unmet need as several of the relapsed/refractory patients are ineligible for autologous CART cell therapies. Invariant natural killer T (iNKT) cells are a unique subset of immune cells that display properties of both T cells and natural killer cells and bridge the innate and adaptive immune responses upon antigen recognition. Unlike conventional β T cells, iNKT cells express an invariant T cell receptor (TCR) that recognize glycolipids presented in the context of the monomorphic, MHC-class I related molecule, CD1d. iNKT cells are ideal cell types for allogeneic, off the shelf approach as they can target cancers without the risk of graft-versus-host disease (GvHD), circumventing the need to delete or knock out the endogenous TCR. Here, we report the engineering of ‘off-the-shelf’ iNKT cells directed against CD19 and their robust in vitro and in vivo functional profile. Briefly, peripheral blood derived iNKT cells were isolated from healthy donors and were engineered to express a CD19 CAR using a 3rd generation lentiviral vector. To demonstrate the CAR-dependent and independent anti-tumor activity, CAR19-iNKT cells were compared in vitro against non-transduced (NT) iNKT cells in cytotoxicity assays and intracellular cytokine staining assays. Allogeneic CAR19-iNKT cells upregulated activation markers, secreted cytokines, and lysed cancer cell lines and primary tumor cells from chronic lymphocytic leukemia and marginal zone lymphoma patients in an antigen-specific manner. Excellent post thaw recovery and viability was noted in cryopreserved CAR19-iNKT cells. Finally, the anti-tumor activity of cryopreserved CAR19-iNKT cells were evaluated in an established aggressive NSG mice model of SEM-luc, a B cell lymphoblastic leukemia cell line expressing luciferase. Robust antitumor activity by CAR19-iNKT cells was observed without any obvious adverse effects compared to controls (untreated and NT iNKT cells). The persistence of CAR19-iNKT cells in this model is currently being evaluated. These data demonstrate a unique, off the shelf CAR19-iNKT cell platform for targeting hematological malignancies that combines the specificity of CD19 targeting CAR with the innate features of iNKT cells. The data indicates that iNKT cells are a potent cell type for generating allogeneic off the shelf products for treating a broad spectrum of hematological malignancies and solid tumors by targeting different receptors on the respective tumors. Citation Format: Kanagaraju Ponnusamy, Janani Kanagaraju, Yingxin Wang, Bryan Lye, Hongwei Ren, Sandhya Buchanan, Michael J. Baker, Mini Bharathan, Anastasios Karadimitris. Engineering allogeneic off-the-shelf CD19-directed CAR-iNKT cells without additional genetic manipulations for the treatment of hematological malignancies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 913.