Exploring a repurposed candidate with dual hIDO1/hTDO2 inhibitory potential for anticancer efficacy identified through pharmacophore-based virtual screening and in vitro evaluation

Discovering effective anti-cancer agents poses a formidable challenge given the limited efficacy of current therapeutic modalities against various cancer types due to intrinsic resistance mechanisms. Cancer immunochemotherapy is an alternative strategy for breast cancer treatment and overcoming cancer resistance. Human Indoleamine 2,3-dioxygenase (hIDO1) and human Tryptophan 2,3-dioxygenase 2 (hTDO2) play pivotal roles in tryptophan metabolism, leading to the generation of kynurenine and other bioactive metabolites. This process facilitates the de novo synthesis of Nicotinamide Dinucleotide (NAD), promoting cancer resistance. This study identified a new dual hIDO1/hTDO2 inhibitor using a drug repurposing strategy of FDA-approved drugs. Herein, we delineate the development of a ligand-based pharmacophore model based on a training set of 12 compounds with reported hIDO1/hTDO2 inhibitory activity. We conducted a pharmacophore search followed by high-throughput virtual screening of 2568 FDA-approved drugs against both enzymes, resulting in ten hits, four of them with high potential of dual inhibitory activity. For further in silico and in vitro biological investigation, the anti-hypercholesterolemic drug Pitavastatin deemed the drug of choice in this study. Molecular dynamics (MD) simulations demonstrated that Pitavastatin forms stable complexes with both hIDO1 and hTDO2 receptors, providing a structural basis for its potential therapeutic efficacy. At nanomolar (nM) concentration, it exhibited remarkable in vitro enzyme inhibitory activity against both examined enzymes. Additionally, Pitavastatin demonstrated potent cytotoxic activity against BT-549, MCF-7, and HepG2 cell lines (IC50 = 16.82, 9.52, and 1.84 µM, respectively). Its anticancer activity was primarily due to the induction of G1/S phase arrest as discovered through cell cycle analysis of HepG2 cancer cells. Ultimately, treating HepG2 cancer cells with Pitavastatin affected significant activation of caspase-3 accompanied by down-regulation of cellular apoptotic biomarkers such as IDO, TDO, STAT3, P21, P27, IL-6, and AhR.

Patterns of Visual Task-based Functional MRI Activation in Chronic Posterior Cerebral Artery Stroke Patients

PURPOSE

Stroke is a principal cause of disability worldwide. In motor stroke, the tools for stratification and prognostication are plentiful. Conversely, in stroke causing mainly visual and cognitive problems, there is still no gold standard modality to use. The purpose of this study was to explore the fMRI recruitment pattern in chronic posterior cerebral artery (PCA) stroke patients and to investigate fMRI as a biomarker of disability in these patients.

METHODS

The study included 10 chronic PCA stroke patients and another 10 age-matched volunteer controls. The clinical presentation, cognitive state, and performance in visual perceptual skills battery (TVPS-3) were determined for both patients and control groups. Task-based fMRI scans were acquired while performing a passive visual task. Individual and group analyses of the fMRI scans as well as correlation analysis with the clinical and behavioral data were done.

RESULTS

At the level of behavioral assessment there was non-selective global impairment in all visual skills subtests. On visual task-based fMRI, patients recruited more brain areas than controls. These activations were present in the ipsilesional side distributed in the ipsilesional cerebellum, dorsolateral prefrontal cortex mainly Brodmann area (BA) 9, superior parietal lobule (somatosensory associative cortex, BA 7), superior temporal gyrus (BA 22), supramarginal gyrus (BA 40), and contralesional associative visual cortex (BA 19). Spearman's rank correlation was computed to assess the relationship between the TVPS scores and the numbers of fMRI neuronal clusters in each patient above the main control activations, there was a negative correlation between the two variables, r(10) = -0.85, p ≤ 0.001.

CONCLUSION

In chronic PCA stroke patients with residual visual impairments, the brain attempts to recruit more neighboring and distant functional areas for executing the impaired visual skill. This intense recruitment pattern in poorly recovering patients appears to be a sign of failed compensation. Consequently, fMRI has the potential for clinically relevant prognostic assessment in patients surviving PCA stroke; however, as this study included no longitudinal data, this potential should be further investigated in longitudinal imaging studies, with a larger cohort, and multiple time points.

MicroRNAs as Potential Orchestrators of Alzheimer's Disease-Related Pathologies: Insights on Current Status and Future Possibilities

Alzheimer's disease (AD) is a progressive and deleterious neurodegenerative disease, strongly affecting the cognitive functions and memory of seniors worldwide. Around 58% of the affected patients live in low and middle-income countries, with estimates of increasing deaths caused by AD in the coming decade. AD is a multifactor pathology. Mitochondrial function declines in AD brain and is currently emerging as a hallmark of this disease. It has been considered as one of the intracellular processes severely compromised in AD. Many mitochondrial parameters decline already during aging; mitochondrial efficiency for energy production, reactive oxygen species (ROS) metabolism and the de novo synthesis of pyrimidines, to reach an extensive functional failure, concomitant with the onset of neurodegenerative conditions. Besides its impact on cognitive functions, AD is characterized by loss of synapses, extracellular amyloid plaques composed of the amyloid-β peptide (Aβ), and intracellular aggregates of hyperphosphorylated Tau protein, accompanied by drastic sleep disorders, sensory function alterations and pain sensitization. Unfortunately, till date, effective management of AD-related disorders and early, non-invasive AD diagnostic markers are yet to be found. MicroRNAs (miRNAs) are small non-coding nucleic acids that regulate key signaling pathway(s) in various disease conditions. About 70% of experimentally detectable miRNAs are expressed in the brain where they regulate neurite outgrowth, dendritic spine morphology, and synaptic plasticity. Increasing studies suggest that miRNAs are intimately involved in synaptic function and specific signals during memory formation. This has been the pivotal key for considering miRNAs crucial molecules to be studied in AD. MicroRNAs dysfunctions are increasingly acknowledged as a pivotal contributor in AD via deregulating genes involved in AD pathogenesis. Moreover, miRNAs have been proved to control pain sensitization processes and regulate circadian clock system that affects the sleep process. Interestingly, the differential expression of miRNA panels implies their emerging potential as diagnostic AD biomarkers. In this review, we will present an updated analysis of miRNAs role in regulating signaling processes that are involved in AD-related pathologies. We will discuss the current challenges against wider use of miRNAs and the future promising capabilities of miRNAs as diagnostic and therapeutic means for better management of AD.

Feather protein lysate optimization and feather meal formation using YNDH protease with keratinolytic activity afterward enzyme partial purification and characterization

Incubation parameters used for the creation of a protein lysate from enzymatically degraded waste feathers using crude keratinase produced by the Laceyella sacchari strain YNDH were optimized using the Response Surface Methodology (RSM); amino acids quantification was also estimated. The optimization elevated the total protein to 2089.5 µg/ml through the application of the following optimal conditions: a time of 20.2 h, a feather concentration (conc.) of 3 g%, a keratinase activity of 24.5 U/100 ml, a pH of 10, and a cultivation temperature of 50 °C. The produced Feather Protein Lysate (FPL) was found to be enriched with essential and rare amino acids. Additionally, this YNDH enzyme group was partially purified, and some of its characteristics were studied. Crude enzymes were first concentrated with an Amicon Ultra 10-k centrifugal filter, and then concentrated proteins were applied to a "Q FF" strong anion column chromatography. The partially purified enzyme has an estimated molecular masses ranging from 6 to 10 kDa. The maximum enzyme activity was observed at 70 °C and for a pH of 10.4. Most characteristics of this protease/keratinase group were found to be nearly the same when the activity was measured with both casein and keratin-azure as substrates, suggesting that these three protein bands work together in order to degrade the keratin macromolecule. Interestingly, the keratinolytic activity of this group was not inhibited by ethylenediamine tetraacetic acid (EDTA), phenylmethanesulfonyl fluoride (PMSF), or iron-caused activation, indicating the presence of a mixed serine-metallo enzyme type.

Effective multi-functional biotechnological applications of protease/keratinase enzyme produced by new Egyptian isolate (Laceyella sacchari YNDH)

BACKGROUND

Due to a multitude of industrial applications of keratinolytic proteases, their demands are increasing. The present investigation studied the production and monitoring of the most possible multi-functional applications of YNDH thermoalkaline keratin-degrading enzyme.

RESULTS

This work is considered the first that reported YNDH strain closely related to Laceyella sacchari strain; YNDH is a producer of protease/keratinase enzyme and able to degrade natural keratin such as feathers, wool, human hairs, and nails. Experimental design Plackett-Burman (PBD) was applied to evaluate culture conditions affecting the production of thermoalkaline protease/keratinase. Afterwards, Box-Behnken design (BBD) was applied to find out the optimum level of significant variables namely, NH₄Cl, yeast extract, and NaNO3 with a predicted activity of 1324.7 U/ml. Accordingly, the following medium composition and parameters were calculated to be optimum (%w/v): NH4Cl, 0.08; feather, 1; yeast extract, 0.04; MgSO₄.7H₂O, 0.02; NaNO₃, 0.016; KH₂PO₄, 0.01; K₂HPO_4, 0.01; pH, 8; inoculum size; 5%, cultivation temperature (Temp.) 45 °C and incubation time 48 h. The studied enzyme can degrade keratin-azure, remove proteinaceous materials, and is able to remove hairs from goat hides. These interesting characteristics make this enzyme a good candidate in many applications especially in detergent (Det.), in leather industries, and in pharmaceuticals particularly in nail treatment.

CONCLUSION

The promising properties of the newly keratin-degrading protease enzyme from Laceyella sacchari strain YNDH would underpin its efficient exploitation in several industries to cope with the demands of worldwide enzyme markets.

Valproic acid potentiates curcumin-mediated neuroprotection in lipopolysaccharide induced rats

The etiology of neuroinflammation is complex and comprises multifactorial, involving both genetic and environmental factors during which diverse genetic and epigenetic modulations are implicated. Curcumin (Cur) and valproic acid (VPA), histone deacetylase 1 inhibitor, have neuroprotective effects. The present study was designed with an aim to investigate the ability of co-treatment of both compounds (Cur or VPA, 200 mg/kg) for 4 weeks to augment neuroprotection and enhance brain recovery from intra-peritoneal injection of (250 μg/kg) lipopolysaccharide-stimulated neuroinflammatory condition on rat brain cortex. Cortex activation and the effects of combined treatment and production of proinflammatory mediators, cyclooxygenase-2 (COX-2), APE1, and nitric oxide/inducible nitric oxide synthase (iNOS) were investigated. Neuroinflammation development was assessed by histological analyses and by investigating associated indices [β-secretase (BACE1), amyloid protein precursor (APP), presenilin (PSEN-1), and PSEN-2)]. Furthermore we measured the expression profile of lethal-7 (let-7) miRNAs members a, b, c, e, and f in all groups, a highly abundant regulator of gene expression in the CNS. Protein and mRNA levels of neuroinflammation markers COX-2, BACE1, APP, and iNOS were also attenuated by combined therapy. On the other hand, assessment of the indicated five let-7 members, showed distinct expression profile pattern in the different groups. Let-7 a, b, and c disappeared in the induced group, an effect that was partially suppressed by co-addition of either Cur or VPA. These data suggest that the combined treatment induced significantly the expression of the five members when compared to rats treated with Cur or VPA only as well as to self-recovery group, which indicates a possible benefit from the synergistic effect of Cur-VPA combination as therapeutic agents for neuroinflammation and its associated disorders. The mechanism elucidated here highlights the particular drug-induced expression profile of let-7 family as new targets for future pharmacological development.

Apurinic/apyrimidinic endonuclease 1 is a key modulator of aluminum-induced neuroinflammation

Background

Chronic administration of Aluminum is proposed as an environmental factor that may affect several enzymes and other biomolecules related to neurotoxicity and Alzheimer's disease (AD). APE1 a multifunctional protein, functions in DNA repair and plays a key role in cell survival versus cell death upon stimulation with cytotoxic agent, making it an attractive emerging therapeutic target. The promising protective effect of resveratrol (resv), which is known to exert potent anti-inflammatory effects on neurotoxicity induced by aluminum chloride (AlCl₃), may be derived from its own antioxidant properties. In the present work we investigated the modulation of APE1 expression during AlCl₃-induced neuroinflammation (25 mg/Kg body weight by oral gavages) in experimental rats. We tested the hypothesis that a reactive oxygen species (ROS)-scavenger, resveratrol at 0.5 mg/kg bodyweight, which is known to exert potent anti-inflammatory effects, would attenuate central inflammation and modulate APE1 expression in AlCl₃-fed rats. Neuroinflammation-induced genes including β-secretase (BACE), amyloid-β precursor protein (APP), presenilin 2 (PSEN-2) and sirt-2 were determined by RT-PCR. APE1 is determined at mRNA and protein levels and confirmed by immunohistochemistry. The expression of pro-inflammatory cytokines (TNF-α, IL6) and iNOS by the rat brain extract were measured by RT-PCR.

Result

Our results indicate that resveratrol may attenuate AlCl₃-induced direct neuroinflammation in rats, and its mechanisms are, at least partly, due to maintaining high APE1 level. Resveratrol co-administration with aluminum chloride exerted more protective effect than pre-administration or treatment of induced rats. A significant elevation of APE1 at both mRNA and protein levels was observed in addition to a marked reduction in β-secretase and amyloid-β. We found that AlCl₃ stimulated the expression of TNF-α, IL-6, and iNOS in rat brain in which NF-κB was involved. Resveratrol inhibited AlCl₃-induced expression and release of TNF-α, IL-6, and iNOS in rat brain.

Conclusions

These findings establish a role for APE1 as a master regulator of AlCl₃ dependent inflammatory responses in rat brain. In addition, there was an ameliorative change with resveratrol against AlCl₃-induced neurotoxicity. These results suggest that rat brain cells produce pro-inflammatory cytokines in response to AlCl₃ in a similar pattern, and further suggest that resveratrol exerts anti-inflammatory effects in rat brain, at least partly, by inhibiting different pro-inflammatory cytokines and key signaling molecules. It might be a potential agent for treatment of neuroinflammation-related diseases, such as AD.

Curcumin and EGCG Suppress Apurinic/Apyrimidinic Endonuclease 1 and Induce Complete Remission in B-cell Non-Hodgkin's lymphoma Patients

Background: Follicular lymphoma (FL) is the most common subtype of indolent lymphoma. FL is still considered to be an incurable disease and palliation of symptoms is an acceptable approach to the expected pattern of repeated relapses due to developing resistance to chemotherapy agents. Apurinic/apyrimidinic endonuclease/redox factor-1 (APE1/Ref-1) is a multifunctional protein involved in DNA base excision repair (BER) of oxidative DNA damage and in redox regulation of a number of transcription factors. It was observed that cytoplasmic APE1 induced COX-2 expression through NF-κB activation. It has been shown that chemopreventive agents potentiate the efficacy of chemotherapy through the regulation of multiple signaling pathways, including NF-κB, c-Myc, cyclooxygenase-2, apoptosis, and others, suggesting a multitargeted nature of chemopreventive agents. We hypothesized that curcumin, a polyphenolic antioxidant derived from the spice turmeric, and epigallocatechin gallate (EGCG) from green tea would potentiate the effect of chemotherapy in B-cell lymphoma.Objective: We examined the role of human apurinic/apyrimidinic endonuclease 1 (APE1) in resistance and prognosis in patients with FL. Our major objective was to update the safety and efficacy results of the antitumor effect of combination of curcumin and EGCG therapy in relapsed or resistant indolent or transformed non-Hodgkin follicular lymphoma patients and their peripheral blood mononuclear cells (PBMCs) compared with healthy donors’ controls. Methods: Thirty patients with FL with over-expression of constitutive active NF-κB in their PBMCs received regular CHOP and consumed capsules compatible with curcumin doses between 0.9 and 5.4 g daily for up to 9 months and 9.0 g/day green tea whole extract "1000 mg tablets of green tea whole extract containing 200 mg EGCG. We designed a dose-escalation study to explore the efficacy of CHOP in combination with curcumin and the green tea extract epigallocatechin-3 gallate (EGCG) on the viability of patients’ peripheral blood mononuclear cells (PBMCs) lymphocytes. Results: Treatment of patients with the combination of curcumin and EGCG, significantly lower cytoplasmic APE1 and the levels of the transcription factor were lower than those predicted from the effects of the CHOP agents (cyclophosphamide, doxorubicin, vincristine, and prednisone) alone, especially with a blunting of the remarkable increases in NF- κB activation induced by CHOP. Eighteen of the patients had a CR (18/30), and twelve patients had PR (12/30) within 9 month treatment and followed up to 12 months. They remain disease-free a mean of 8.6 y (range, 7.9–9.2 y) after this combination therapy.Conclusion: Optimal patient benefit might be obtained in follicular lymphoma when administering curcumin up-front in combination with chemotherapy and EGCG treatment. The combination of curcumin with EGCG resulted in a synergistic antitumor activity and that with CHOP agents in additivity or sub-additivity, down-regulated the expression of all NF-κB regulated gene products, leading to the suppression of angiogenesis, metastasis and entering in complete remission as indicated by β2-microglobulin and lactate dehydrogenase (LDH) levels. Key words: Curcumin, EGCG, B- cell NHL, NF-κB, VEGF, APE1, lymphoma

Alteration of AP-endonuclease1 expression in curcumin-treated fibrotic rats

BACKGROUND

Apurinic/apyrimidinic endonuclease1/ redox factor-1 (APE1/Ref-1) is a multifunctional protein involved in DNA base excision repair and redox regulation of many transcription factors. It is an important pro-survival protein activated in response to oxidative stress. Increased level of this essential redox sensitive protein correlates closely with cellular survival against oxidative insults. Curcumin (diferuloylmethane) a naturally occurring compound derived from turmeric has attracted interest because of its anti-inflammatory, anti-oxidative, and chemopreventive activities.

MATERIAL AND METHODS

The current study evaluates the in vivo role of curcumin in protecting and treating liver injury and fibrogenesis caused by carbon tetrachloride (CCl4) in rats. It also addresses the possible involvement of the multifunctional protein APE1 in hepatoprotection. Analysis of APE1 expression was performed at mRNA and protein levels by reverse transcriptase (RT)-PCR and western blotting respectively. Profile of HSCs-activation related genes were assayed by RT-PCR and pro-inflammatory cytokines levels were determined by enzyme-linked immune assays.

RESULTS

Here we show that oral administration of curcumin was accompanied by a robust increase in APE1 protein and mRNA levels, and improved the histological architecture of rat liver. In addition, curcumin attenuated oxidative stress by increasing the content of hepatic glutathione within normal values, leading to the reduction in the level of lipid hydroperoxide. Curcumin remarkably suppressed inflammation by reducing levels of inflammatory cytokines, including tumor necrosis factor-α (TNF-α), nuclear factor-kappa B (NF-κB) and interleukin-6 (IL-6). It also inhibited hepatic stellate cells (HSCs) activation by elevating the level of PPARγ and reducing the abundance of transforming growth factor-β (TGF-β). We found that oral administration of curcumin at 200 mg/kg dose not only protected against CCl4-induced hepatic injury, but also resulted in more than two-fold induction of APE1 protein expression in CCl4-induced rat group.

CONCLUSIONS

It can be concluded that curcumin reduced markers of liver damage in rats treated with CCl4, with concomitant elevation in APE1 protein level indicating a possible protective effect with unknown mechanism. The induction of DNA repair enzymes may be an important and novel strategy for hepatic protection against oxidative injury.

Modulation of AP-endonuclease1 levels associated with hepatic cirrhosis in rat model treated with human umbilical cord blood mononuclear stem cells

Oxidative stress in liver cells may contribute to the etiology of hepatic diseases, as in liver cirrhosis. AP-Endonuclease1 (APE1/Ref-1) is essential for cell protection toward oxidative stress by acting as a transcriptional regulator of pro-survival genes and as a redox sensitive protein. The aim of this study was to critically analyze the various parameters governing the success of human umbilical cord blood mononuclear stem cell-based (MNCs) therapy without the use of an immunosuppressant and to investigate for the first time the expression of APE1 during thioacetamide (TAA)-induced cirrhosis and MNCs therapy in a rat model. Umbilical cord blood samples from full-term deliveries were collected. Lethal fulminant hepatic cirrhosis in rats was induced by intraperitoneal injection of thio-acetamide. MNCs were then intrahepatically transplanted. We measured APE1 expression at mRNA and protein levels, mRNA expression of TGF-β, α-SMA, STAP, CTGF, MMP-9 and TIMP-1 in a follow up study. Histopathological and immunohistochemical analyses were performed 10 weeks after intrahepatic injection of the cells. Transdifferentiated cells could be efficiently stained with antihuman hepatocytes. Interestingly, human hepatocyte-specific markers, human albumin, cytokeratin-18 and cytokeratin-19 mRNAs were detected in rat liver after 10 days of MNCs infusion. MNC transplanted by intrahepatic route, could engraft recipient liver, differentiated into functional hepatocytes, and rescued liver failure. Moreover up regulation of APE1 expression confirmed by marked immunohistochemical staining may be involved in MNCs-induced hepatocytes regeneration suggesting that maintaining high level of APE1 has protective effect as pro-survival signal.

Accelerated onset of albuminuria in diabetic rats preimmunized with glucosylated rat serum albumin

Young adult rats were immunized with either in vitro glucosylated or unmodified rat serum albumin (RSA) followed by induction of the diabetic state. At various times after streptozotocin administration, sera were evaluated for specific antibody response using the enzyme-linked immunosorbent assay while urine was monitored for the presence of albumin by radial immunodiffusion. The data indicate that glucosylated RSA is capable of eliciting the production of antibodies, but unmodified RSA is not. The specificity of the generated antibodies appears to be directed toward the glucitol-lysine residues of the modified albumin. Preimmunization of rats with glucosylated RSA followed by induction of diabetes causes a rapid decline in specific antibody titers and greatly enhances the rate of progression to albuminuria. These results demonstrate that in vitro and in vivo glucosylation of an endogenous protein provide products with identical antigenicity. They also suggest an animal model for the study of diabetic autoimmunity involving glucosylated endogenous proteins.

Glucosylated collagen is antigenic

Sera from rats inoculated with in vitro glucosylated rat skin acid-soluble collagen were evaluated for specific antibody response using the enzyme-linked immunosorbent assay. The data indicate that the altered protein is capable of eliciting the production of antibodies, but unmodified collagen is not. The specificity of the generated antibodies appears to be directed toward the glucitollysine residues of the modified collagen. Sera from streptozotocin-induced diabetic rats contain antibodies that clearly bind glucosylated collagen. These results provide support for the hypothesis that in diabetes mellitus increased collagen glucosylation during chronic hyperglycemia may be the initiating event of an autoimmune response leading to the long-term complications.