Identification of a natural product-like STAT3 dimerization inhibitor by structure-based virtual screening

A mitochondria-targeted iridium(III) complex-based sensor for endogenous GSH detection in living cells

Glutathione (GSH) plays an important role in maintaining redox homeostasis in biological systems. Development of reliable glutathione sensors is of great significance to better understand the role of biomolecules in living cells and organisms. Based on the advantages of the photophysical properties of iridium complexes, we proposed a "turn-on" phosphorescent sensor. Ir-DNFB has the characteristics of a large Stokes shift, high sensitivity for GSH detection, low cytotoxicity, and extremely short response time, and can specifically analyze glutathione in living cells and highly target endogenous glutathione in mitochondria. The N-H group on the imidazole ring of Ir-DNFB could form a new electrostatic interaction with the α-carboxyl group on the glutamate moiety of glutathione. The nucleophilic attack reaction was regulated by the sulfhydryl group on GSH, following which the ether bond linking the 2,4-dinitrobenzene to probe Ir-DNFB was broken, accompanied with a phosphorescence enhancement. Most importantly, the process of recognizing glutathione was not affected by other amino acids. Overall, this work provided a very useful tool for rapidly distinguishing between normal, inflammatory, and progressive tumor cells.

Computational screening and molecular dynamics of natural compounds targeting the SH2 domain of STAT3: a multitarget approach using network pharmacology

SH2 (Src Homology 2) domains play a crucial role in phosphotyrosine-mediated signaling and have emerged as promising drug targets, particularly in cancer therapy. STAT3 (Signal Transducer and Activator of Transcription 3), which contains an SH2 domain, plays a pivotal role in cancer progression and immune evasion because it facilitates the dimerization of STAT3, which is essential for their activation and subsequent nuclear translocation. SH2 domain-mediated STAT3 inhibition disrupts this binding, reduces phosphorylation of STAT3, and impairs dimerization. This study employed an in silico approach to screen potential natural compounds that could target the SH2 domain of STAT3 and inhibit its function. The phytomolecules (182455) were retrieved from the ZINC 15 database and were docked using various modes like HTVS, SP, and XP. The phytomolecules exhibiting higher binding affinity were selected. MM-GBSA was performed to determine binding free energy, and the QikProp tool was utilized to assess the pharmacokinetic properties of potential hit compounds, narrowing down the list of candidates. Molecular dynamics simulations, thermal MM-GBSA, and WaterMap analysis were performed on compounds that exhibited favorable binding affinities and pharmacokinetic characteristics. Based on docking scores and binding interactions, ZINC255200449, ZINC299817570, ZINC31167114, and ZINC67910988 were identified as potential STAT3 inhibitors. ZINC67910988 demonstrated superior stability in molecular dynamics simulation and WaterMap analysis. Furthermore, DFT was performed to determine energetic and electronic properties, and HOMO and LUMO sites were predicted for electronic structure calculation. Additionally, network pharmacology was performed to map the compounds' interactions within biological networks, highlighting their multitarget potential. Compound-target networks elucidate the relationships between compounds and multiple targets, along with their associated pathways and help to minimize off-target effects. The identified lead compound showed strong potential as a STAT3 inhibitor, warranting further validation through in vitro and in vivo studies.

STAT3 and the STAT3‑regulated inhibitor of apoptosis protein survivin as potential therapeutic targets in colorectal cancer (Review)

Colorectal cancer (CRC) is one of the leading types of cancer worldwide. CRC development has been associated with the constitutive activation of signal transducer and activator of transcription 3 (STAT3). STAT3 is a master regulator of inflammation during cancer-associated colitis, and becomes upregulated in CRC. In CRC, STAT3 is activated by IL-6, among other pro-inflammatory cytokines, inducing the expression of target genes that stimulate proliferation, angiogenesis and the inhibition of apoptosis. One of the main STAT3-regulated inhibitors of apoptosis is survivin, which is a bifunctional protein that regulates apoptosis and participates in cell mitosis. Survivin expression is normally limited to foetal tissue; however, survivin is also upregulated in tumours. In silico and experimental analyses have shown that the STAT3 interactome is relevant during CRC progression, and the constitutive STAT3-survivin axis participates in development of the tumour microenvironment and response to therapy. The presence of a STAT3-survivin axis has been documented in CRC cohorts, and the expression of these molecules is associated with poor prognosis and a higher mortality rate in patients with CRC. Thus, STAT3, survivin, and the upstream activators IL-6 and IL-6 receptor, are considered therapeutic targets for CRC. Efforts to develop drugs targeting the STAT3-survivin axis include the evaluation of phytochemical compounds, small molecules and monoclonal antibodies. In the present review, the expression, function and participation of the STAT3-survivin axis in the progression of CRC were investigated. In addition, an update on the pre-clinical and clinical trials evaluating potential treatments targeting the STAT3-survivin axis is presented.

In-silico assessment of novel peptidomimetics inhibitor targeting STAT3 and STAT4 N-terminal domain dimerization: A comprehensive study using molecular docking, molecular dynamics simulation, and binding free energy analysis

Dysregulation in Janus kinase-Signal Transducer and Activation of Transcription (JAK-STAT) pathway is closely linked to various cancer types. The N-terminal domain (NTD) of STAT proteins, upon dimerization, assumes a multifaceted role with remarkable adaptability in mediating interactions between proteins. Consequently, the strategic targeting of the N-terminal domain of STATs has emerged as a promising tactic for disrupting dimerization and impeding the translocation of STAT proteins. In this study, we have deployed an integrated in-silico methodology to rationally design Peptidomimetic foldamers as inhibitors of the N-terminal domains of STAT3 and STAT4, with the objective of disrupting protein dimerization. Consequently, we have judiciously designed a series of peptidomimetics that encompass β3-amino acids, bearing side chains that mimic the residues within interface II of the dimeric structures of the NTDs. Employing molecular docking techniques; we have assessed the binding affinity of these designed peptidomimetics toward both the NTDs. Furthermore, we have conducted an evaluation of the stability and conformational alterations within the docked complexes over an extensive Molecular Dynamics, subsequently computing the binding free energy utilizing MM/PBSA calculations. Our findings unequivocally demonstrate that the peptidomimetic foldamers we have devised (Peptide-A, Peptide-B, and Peptide-C) exhibit a propensity to bind to and impede the dimerization process of the NTDs of both STAT3 and STAT4. These outcomes serve to underscore the potential of these meticulously designed peptidomimetics as potential candidates meriting further exploration in the realm of cancer prevention and management.

Structure-Based identification of a potent KDM7A inhibitor exerts anticancer activity through transcriptionally reducing MKRN1 in taxol- resistant and -sensitive triple-negative breast cancer cells

KDM7A, a histone demethylase implicated in cancer proliferation, metastasis, and drug resistance, represents a crucial therapeutic target. Utilizing "mcule.com" for virtual screening of 100,000 compounds from the ZINC database, we identified 12 compounds with high affinity for KDM7A, with compound 4 emerging as the leading candidate for effectively inhibiting KDM7A's demethylase activity. Analysis of the GTRD database, the Breast Cancer Gene Expression Miner website, and recent studies highlighted MKRN1, a gene associated with cell proliferation and drug resistance, as a key intersecting factor. Compared to 2,4-pyridine dicarboxylic acid, compound 4 significantly reduced breast cancer stem cells and induced G1 phase cell cycle arrest. Mechanistically, compound 4 inhibited KDM7A's binding to H3K27me3, decreased MKRN1 transcription, and increased the levels of cell cycle regulators p16, p21, and p27, while reducing stem cell markers ALDH1A1, CD44, and CD133. These findings suggest that compound 4 could serve as a promising lead for selective KDM7A-targeting drugs. Additionally, this study is the first to demonstrate MKRN1 as a downstream gene of KDM7A, showing significant inhibitory effects in both taxol-resistant and drug-sensitive triple-negative breast cancer (TNBC) cells. This research offers new insights into the anticancer mechanisms of KDM7A inhibitors and underscores KDM7A's potential as a therapeutic target against TNBC.

TTI-101 targets STAT3/c-Myc signaling pathway to suppress cervical cancer progression: an integrated experimental and computational analysis

BACKGROUND

Cervical cancer (CC) is a significant global health concern, demanding the consideration of novel therapeutic strategies. The signal transducer and activator of transcription 3 (STAT3) pathway has been implicated in cancer progression and is a potential target for therapeutic intervention. This study aimed to explore the therapeutic potential of TTI-101, a small molecule STAT3 inhibitor, in CC and investigate its underlying mechanisms.

METHODS

Molecular docking studies and molecular dynamics simulations were performed to explore the binding interaction between TTI-101 and STAT3 and assess the stability of the STAT3-TTI-101 complex. Cell viability assays, wound healing assays, colony formation assays, flow cytometry analysis, and gene expression analysis were conducted. In vivo xenograft models were used to assess the antitumor efficacy of TTI-101.

RESULTS

The in silico analysis shows a stable binding interaction between TTI-101 and STAT3. TTI-101 treatment inhibits cell viability, clonogenic ability, and cell migration in CC cells. Furthermore, TTI-101 induces apoptosis and cell cycle arrest. Analysis of apoptosis-related markers demonstrated dysregulation of Bax, Bcl-2, and Caspase-3 upon TTI-101 treatment. Moreover, TTI-101 caused G2/M phase arrest accompanied by a decrease in CDK1 and Cyclin B1 at mRNA levels. In the xenograft model, TTI-101 significantly inhibited tumor growth without adverse effects on body weight.

CONCLUSION

TTI-101 exhibited anticancer effects by targeting the STAT3/c-Myc signaling pathway, inducing cell cycle arrest, and promoting apoptosis in CC cells. These findings provide valuable insights into the development of novel therapeutic strategies for cervical cancer. Further investigation is warranted to validate the clinical application of TTI-101.

Leonurine ameliorates the STAT3 pathway through the upregulation of SHP-1 to retard the growth of hepatocellular carcinoma cells

Signal transducer and activator of transcription 3 (STAT3) is a transcription factor that directs the transcription of genes involved in the promotion of cell survival and proliferation, inflammation, angiogenesis, invasion, and migration. Overactivation of STAT3 is often witnessed in human cancers, thereby making it a good target in oncology. Herein the efficacy of Leonurine (Leo), a bioactive alkaloid present in Herba leonuri, was investigated for its STAT3-inhibitory potential in hepatocellular carcinoma (HCC) cells. Leo downregulated the persistent as well as IL-6-driven activation of STAT3. Leo abrogated the nuclear localization and DNA interacting ability of STAT3. Leo was also found to impart STAT3 inhibition by mitigating the activation of upstream kinases such as JAK1, JAK2, and Src both in constitutive and IL-6 inducible systems. Leo curbed the STAT3-driven luciferase gene expression and the depletion of STAT3 resulted in the reduced responsiveness of HCC cells to Leo. Pervanadate exposure counteracted Leo-induced STAT3 inhibition suggesting the involvement of a protein tyrosine phosphatase. SHP-1 was significantly elevated upon Leo exposure whereas the depletion of SHP-1 was found to revert the effect of Leo on STAT3. Leo induced apoptosis and also significantly potentiated the cytotoxic effect of paclitaxel, doxorubicin, and sorafenib. Leo was found to be non-toxic up to the dose of 10 mg/kg in NCr nude mice. In conclusion, Leo was demonstrated to induce cytotoxicity in HCC cells by mitigating the persistent of activation of STAT3 pathway.

Anticancer Drug Discovery Based on Natural Products: From Computational Approaches to Clinical Studies

Globally, malignancies cause one out of six mortalities, which is a serious health problem. Cancer therapy has always been challenging, apart from major advances in immunotherapies, stem cell transplantation, targeted therapies, hormonal therapies, precision medicine, and palliative care, and traditional therapies such as surgery, radiation therapy, and chemotherapy. Natural products are integral to the development of innovative anticancer drugs in cancer research, offering the scientific community the possibility of exploring novel natural compounds against cancers. The role of natural products like Vincristine and Vinblastine has been thoroughly implicated in the management of leukemia and Hodgkin's disease. The computational method is the initial key approach in drug discovery, among various approaches. This review investigates the synergy between natural products and computational techniques, and highlights their significance in the drug discovery process. The transition from computational to experimental validation has been highlighted through in vitro and in vivo studies, with examples such as betulinic acid and withaferin A. The path toward therapeutic applications have been demonstrated through clinical studies of compounds such as silvestrol and artemisinin, from preclinical investigations to clinical trials. This article also addresses the challenges and limitations in the development of natural products as potential anti-cancer drugs. Moreover, the integration of deep learning and artificial intelligence with traditional computational drug discovery methods may be useful for enhancing the anticancer potential of natural products.

Hesperidin, a Bioflavonoid in Cancer Therapy: A Review for a Mechanism of Action through the Modulation of Cell Signaling Pathways

Cancer represents one of the most frequent causes of death in the world. The current therapeutic options, including radiation therapy and chemotherapy, have various adverse effects on patients' health. In this vista, the bioactive ingredient of natural products plays a vital role in disease management via the inhibition and activation of biological processes such as oxidative stress, inflammation, and cell signaling molecules. Although natural products are not a substitute for medicine, they can be effective adjuvants or a type of supporting therapy. Hesperidin, a flavonoid commonly found in citrus fruits, with its potential antioxidant, anti-inflammatory, and hepatoprotective properties, and cardio-preventive factor for disease prevention, is well-known. Furthermore, its anticancer potential has been suggested to be a promising alternative in cancer treatment or management through the modulation of signal transduction pathways, which includes apoptosis, cell cycle, angiogenesis, ERK/MAPK, signal transducer, and the activator of transcription and other cell signaling molecules. Moreover, its role in the synergistic effects with anticancer drugs and other natural compounds has been described properly. The present article describes how hesperidin affects various cancers by modulating the various cell signaling pathways.

Research progress of STAT3-based dual inhibitors for cancer therapy

Signal transducer and activator of transcription 3 (STAT3), a transcription factor, regulates gene levels that are associated with cell survival, cell cycle, and immune reaction. It is correlated with the grade of malignancy and the development of various cancers and targeting STAT3 protein is a potentially promising therapeutic strategy for tumors. Over the past 20 years, various compounds have been found to directly inhibit STAT3 activity via different strategies. However, numerous difficulties exist in the development of STAT3 inhibitors, such as serious toxic effects, poor therapeutic effects, and intrinsic and acquired drug resistance. STAT3 inhibitors synergistically suppress cancer development with additional anti-tumor drugs, such as indoleamine 2,3-dioxygenase 1 inhibitors (IDO1i), histone deacetylase inhibitors (HDACi), DNA inhibitors, pro-tumorigenic cytokine inhibitors (PTCi), NF-κB inhibitors, and tubulin inhibitors. Therefore, individual molecule- based dual-target inhibitors can be the candidate alternative or complementary treatment to overcome the disadvantages of just STAT3 or other targets as a monotherapy. In this review, we discuss the theoretical basis for formulating STAT3-based dual-target inhibitors and also summarize their structure-activity relationships (SARs).

The Potential Role of Fisetin, a Flavonoid in Cancer Prevention and Treatment

Cancer is a main culprit and the second-leading cause of death worldwide. The current mode of treatment strategies including surgery with chemotherapy and radiation therapy may be effective, but cancer is still considered a major cause of death. Plant-derived products or their purified bioactive compounds have confirmed health-promoting effects as well as cancer-preventive effects. Among these products, flavonoids belong to polyphenols, chiefly found in fruits, vegetables and in various seeds/flowers. It has been considered to be an effective antioxidant, anti-inflammatory and to play a vital role in diseases management. Besides these activities, flavonoids have been revealed to possess anticancer potential through the modulation of various cell signaling molecules. In this regard, fisetin, a naturally occurring flavonoid, has a confirmed role in disease management through antioxidant, neuro-protective, anti-diabetic, hepato-protective and reno-protective potential. As well, its cancer-preventive effects have been confirmed via modulating various cell signaling pathways including inflammation, apoptosis, angiogenesis, growth factor, transcription factor and other cell signaling pathways. This review presents an overview of the anti-cancer potential of fisetin in different types of cancer through the modulation of cell signaling pathways based on in vivo and in vitro studies. A synergistic effect with anticancer drugs and strategies to improve the bioavailability are described. More clinical trials need to be performed to explore the anti-cancer potential and mechanism-of-action of fisetin and its optimum therapeutic dose.

Role of STAT3 in the pathogenesis of nasopharyngeal carcinoma and its significance in anticancer therapy

Nasopharyngeal carcinoma (NPC) is a type of head and neck tumor with noticeable regional and ethnic differences. It is associated with Epstein-Barr virus infection and has a tendency for local and distant metastasis. NPC is also highly sensitive to radiotherapy and chemotherapy. Over 70% of patients present with locoregionally advanced disease, and distant metastasis is the primary reason for treatment failure. A signal transducer and activator of transcription 3 (STAT3) promotes NPC oncogenesis through mechanisms within cancerous cells and their interactions with the tumor microenvironment, which is critical in the initiation, progression, and metastasis of NPC. Further, p-STAT3 is strongly associated with advanced NPC. Recent research on STAT3 has focused on its expression at the center of various oncogenic pathways. Here, we discuss the role of STAT3 in NPC and its potential therapeutic inhibitors and analogs for the treatment and control of NPC.

Polypharmacology-based approach for screening TCM against coinfection of Mycoplasma gallisepticum and Escherichia coli

Natural products and their unique polypharmacology offer significant advantages for finding novel therapeutics particularly for the treatment of complex diseases. Meanwhile, Traditional Chinese Medicine exerts overall clinical benefits through a multi-component and multi-target approach. In this study, we used the previously established co-infection model of Mycoplasma gallisepticum and Escherichia coli as a representative of complex diseases. A new combination consisting of 6 herbs were obtained by using network pharmacology combined with transcriptomic analysis to reverse screen TCMs from the Chinese medicine database, containing Isatdis Radix, Forsythia Fructus, Ginkgo Folium, Mori Cortex, Licorice, and Radix Salviae. The results of therapeutic trials showed that the Chinese herbal compounds screened by the target network played a good therapeutic effect in the case of co-infection. In summary, these data suggested a new method to validate target combinations of natural products that can be used to optimize their multiple structure-activity relationships to obtain drug-like natural product derivatives.

Bioinformatics-Guided Identification of Ethyl Acetate Extract of Citri Reticulatae Pericarpium as a Functional Food Ingredient with Anti-Inflammatory Potential

Citri Reticulatae Pericarpium (CRP) is one of the most commonly used food supplements and folk medicines worldwide, and possesses cardiovascular, digestive, and respiratory protective effects partially through its antioxidant and anti-inflammatory functions. The unique aromatic flavor and mild side effects make CRP a promising candidate for the development of anti-inflammatory functional food. However, recent studies show that the crude alcoholic extract and some isolated compounds of CRP show compromised anti-inflammatory activity, which became the main factor hindering its further development. To identify the bioactive compounds with anti-inflammatory potential, and improve the anti-inflammatory effects of the extract, a bioinformatics-guided extraction protocol was employed in this study. The potential bioactive candidates were identified by combing network pharmacology analysis, molecular docking, principal components analysis, k-means clustering, and in vitro testing of reference compounds. Our results demonstrated that 66 compounds in CRP could be grouped into four clusters according to their docking score profile against 24 receptors, while the cluster containing flavonoids and phenols might possess a more promising anti-inflammatory function. In addition, in vitro anti-inflammatory tests of the seven reference compounds demonstrated that hesperitin, naringenin, and gardenin B, which were grouped into a cluster containing flavonoids and phenols, significantly decreased LPS-induced NO, TNF-α, and IL-6 production of macrophages. While the compounds outside of that cluster, such as neohesperidin, naringin, hesperidin, and sinensetin showed little effect on alleviating LPS-induced NO and proinflammatory cytokine production. Based on the chemical properties of selected compounds, ethyl acetate (EtOAc) was selected as the solvent for extraction, because of its promising solubility of flavonoids and phenols. Furthermore, the ethanol alcoholic extract was used as a reference. The chemical profiling of EtOAc and crude alcoholic extract by HPLC/MS/MS also demonstrated the decreased abundance of flavonoid glycosides in EtOAc extract but increased abundance of phenols, phenolic acid, and aglycones. In accordance with the prediction, the EtOAc extract of CRP, but not the crude alcoholic extract, significantly decreased the NO, IL-6, and TNF-α production. Taken together, the results suggested selective extraction of phenols and flavonoids rich extract was able to increase the anti-inflammatory potential of CRP partially because of the synergistic effects between flavonoids, phenols, and enriched polymethoxyflavones. Our study might pave the road for the development of ethyl acetate extract of CRP as a novel functional food with anti-inflammatory function.

Insights into the Cardiotoxic Effects of Veratrum Lobelianum Alkaloids: Pilot Study

Jervine, protoveratrine A (proA), and protoveratrine B (proB) are Veratrum alkaloids that are presented in some remedies obtained from Veratrum lobelianum, such as Veratrum aqua. This paper reports on a single-center pilot cardiotoxic mechanism study of jervine, proA, and proB in case series. The molecular aspects were studied via molecular dynamic simulation, molecular docking with cardiac sodium channel Na_V1.5, and machine learning-based structure–activity relationship modeling. HPLC-MS/MS method in combination with clinical events were used to analyze Veratrum alkaloid cardiotoxicity in patients. Jervine demonstrates the highest docking score (−10.8 kcal/mol), logP value (4.188), and pK_a value (9.64) compared with proA and proB. Also, this compound is characterized by the lowest calculated IC₅₀. In general, all three analyzed alkaloids show the affinity to Na_V1.5 that highly likely results in cardiotoxic action. The clinical data of seven cases of intoxication by Veratrum aqua confirms the results of molecular modeling. Patients exhibited nausea, muscle weakness, bradycardia, and arterial hypotension. The association between alkaloid concentrations in blood and urine and severity of patient condition is described. These experiments, while primary, confirmed that jervine, proA, and proB contribute to cardiotoxicity by Na_V1.5 inhibition.

Novel STAT3 Inhibitors Targeting STAT3 Dimerization by Binding to the STAT3 SH2 Domain

Our drug discovery model has identified two novel STAT3 SH2 domain inhibitors 323–1 and 323–2 (delavatine A stereoisomers) in a series of experiments. In silico computational modeling, drug affinity responsive target stability (DARTS), and fluorescence polarization (FP) assays altogether determined that 323–1 and 323–2 directly target the STAT3 SH2 domain and inhibited both phosphorylated and non-phosphorylated STAT3 dimerization. Computational docking predicted that compound 323s bind to three subpockets of the STAT3 SH2 domain. The 323s inhibition of STAT3 dimerization was more potent than the commercial STAT3 SH2 domain inhibitor S3I-201 in the co-immunoprecipitation assay, correlating with computational docking data. The fluorescence polarization assay further confirmed that the compound 323s target the STAT3 SH2 domain by competitively abrogating the interaction between STAT3 and the SH2-binding peptide GpYLPQTV. Compared with S3I-201, the 323 compounds exhibited stronger inhibition of STAT3 and reduced the level of IL-6-stimulated phosphorylation of STAT3 (Tyr705) in LNCaP cells over the phosphorylation of STAT1 (Tyr701) induced by IFN-ɣ in PC3 cells or the phosphorylation of STAT1 (Ser727) in DU145 cells. Both compounds downregulated STAT3 target genes MCL1 and cyclin D1. Thus, the two compounds are promising lead compounds for the treatment of cancers with hyper-activated STAT3.

SINBAD, structural, experimental and clinical characterization of STAT inhibitors and their potential applications

The abnormal activation of signal transducer and activator of transcription (STAT) protein family is recognized as cause or driving force behind multiple diseases progression. Therefore, searching for potential treatment strategy is pursued by multiple scientific groups. We consider that providing comprehensive, integrated and unified dataset for STAT inhibitory compounds may serve as important tool for other researchers. We developed SINBAD (STAT INhbitor Biology And Drug-ability) in response to our experience with inhibitory compound research, knowing that gathering detailed information is crucial for effective experiment design and also for finding potential solutions in case of obtaining inconclusive results. SINBAD is a curated database of STAT inhibitors which have been published and described in scientific articles providing prove of their inhibitory properties. It is a tool allowing easy analysis of experimental conditions and provides detailed information about known STAT inhibitory compounds.

Computational strategies to identify new drug candidates against neuroinflammation

The even more increasing application of computational approaches in these last decades has deeply modified the process of discovery and commercialization of new therapeutic entities. This is especially true in the field of neuroinflammation, in which both the peculiar anatomical localization and the presence of the blood-brain barrier makeit mandatory to finely tune the candidates' physicochemical properties from the early stages of the discovery pipeline. The aim of this review is therefore to provide a general overview to the readers about the topic of neuroinflammation, together with the most common computational strategies that can be exploited to discover and design small molecules controlling neuroinflammation, especially those based on the knowledge of the three-dimensional structure of the biological targets of therapeutic interest. The techniques used to describe the molecular recognition mechanisms, such as molecular docking and molecular dynamics, will therefore be eviscerated, highlighting their advantages and their limitations. Finally, we report several case studies in which computational methods have been applied in drug discovery on neuroinflammation, focusing on the last decade's research.

Repurposing FDA-Approved Compounds for the Discovery of Glutaminyl Cyclase Inhibitors as Drugs Against Alzheimer's Disease

Alzheimer's disease (AD) is one of the most common neurodegenerative causes of dementia, the pathology of which is still not much clear. It's challenging to discover the disease modifying agents for the prevention and treatment of AD over the years. Emerging evidence has been accumulated to reveal the crucial role of up-regulated glutaminyl cyclase (QC) in the initiation of AD. In the current study, the QC inhibitory potency of a library consisting of 1621 FDA-approved compounds was assessed. A total of 54 hits, 3.33 % of the pool, exhibited QC inhibitory activities. The Ki of the top 5 compounds with the highest QC inhibitory activities were measured. Among these selected hits, compounds affecting neuronal signaling pathways and other mechanisms were recognized. Moreover, several polyphenol derivatives with QC inhibitory activities were also identified. Frameworks and subsets contained in these hits were analyzed. Taken together, our results may contribute to the discovery and development of novel QC inhibitors as potential anti-AD agents.

Artificial intelligence to deep learning: machine intelligence approach for drug discovery

Drug designing and development is an important area of research for pharmaceutical companies and chemical scientists. However, low efficacy, off-target delivery, time consumption, and high cost impose a hurdle and challenges that impact drug design and discovery. Further, complex and big data from genomics, proteomics, microarray data, and clinical trials also impose an obstacle in the drug discovery pipeline. Artificial intelligence and machine learning technology play a crucial role in drug discovery and development. In other words, artificial neural networks and deep learning algorithms have modernized the area. Machine learning and deep learning algorithms have been implemented in several drug discovery processes such as peptide synthesis, structure-based virtual screening, ligand-based virtual screening, toxicity prediction, drug monitoring and release, pharmacophore modeling, quantitative structure-activity relationship, drug repositioning, polypharmacology, and physiochemical activity. Evidence from the past strengthens the implementation of artificial intelligence and deep learning in this field. Moreover, novel data mining, curation, and management techniques provided critical support to recently developed modeling algorithms. In summary, artificial intelligence and deep learning advancements provide an excellent opportunity for rational drug design and discovery process, which will eventually impact mankind. The primary concern associated with drug design and development is time consumption and production cost. Further, inefficiency, inaccurate target delivery, and inappropriate dosage are other hurdles that inhibit the process of drug delivery and development. With advancements in technology, computer-aided drug design integrating artificial intelligence algorithms can eliminate the challenges and hurdles of traditional drug design and development. Artificial intelligence is referred to as superset comprising machine learning, whereas machine learning comprises supervised learning, unsupervised learning, and reinforcement learning. Further, deep learning, a subset of machine learning, has been extensively implemented in drug design and development. The artificial neural network, deep neural network, support vector machines, classification and regression, generative adversarial networks, symbolic learning, and meta-learning are examples of the algorithms applied to the drug design and discovery process. Artificial intelligence has been applied to different areas of drug design and development process, such as from peptide synthesis to molecule design, virtual screening to molecular docking, quantitative structure-activity relationship to drug repositioning, protein misfolding to protein-protein interactions, and molecular pathway identification to polypharmacology. Artificial intelligence principles have been applied to the classification of active and inactive, monitoring drug release, pre-clinical and clinical development, primary and secondary drug screening, biomarker development, pharmaceutical manufacturing, bioactivity identification and physiochemical properties, prediction of toxicity, and identification of mode of action.

An optimized BRD4 inhibitor effectively eliminates NF-κB-driven triple-negative breast cancer cells

Acetylation of NF-κB's RelA subunit at lysine-310 (AcLys310) helps to maintain constitutive NF-κB activity in cancers such as triple-negative breast cancer (TNBC). Bromodomain-containing factor BRD4 binds to acetylated RelA to promote the activity of NF-κB. Hence, interfering with the acetylated RelA-BRD4 interaction is a potential strategy for treating NF-κB-driven TNBC. Here, a new compound 13a was obtained by structural optimization and modification of our previously reported compound. In comparison with the well-known BRD4 inhibitor (+)-JQ1, 13a showed more potent anticancer activity in NF-κB-active MDA-MB-231 cells. Mechanistically, 13a antagonized the protein-protein interaction (PPI) between BRD4 and acetylated RelA, decreased levels of IL-6, IL-8, Snail, Vimentin, and ZEB1, induced cell senescence and DNA damage, and weakened the adhesion, metastasis, and invasion ability of TNBC cells. Our results provide insights into avenues for the further development of potent BRD4-acetylated RelA PPI inhibitors. Moreover, our findings highlight the effectiveness and feasibility of blocking the interaction between BRD4 and acetylated RelA against NF-κB-active cancers, and of screening antagonists of this PPI.

Lung Cancer Management with Silibinin: A Historical and Translational Perspective

The flavonolignan silibinin, the major bioactive component of the silymarin extract of Silybum marianum (milk thistle) seeds, is gaining traction as a novel anti-cancer therapeutic. Here, we review the historical developments that have laid the groundwork for the evaluation of silibinin as a chemopreventive and therapeutic agent in human lung cancer, including translational insights into its mechanism of action to control the aggressive behavior of lung carcinoma subtypes prone to metastasis. First, we summarize the evidence from chemically induced primary lung tumors supporting a role for silibinin in lung cancer prevention. Second, we reassess the preclinical and clinical evidence on the effectiveness of silibinin against drug resistance and brain metastasis traits of lung carcinomas. Third, we revisit the transcription factor STAT3 as a central tumor-cell intrinsic and microenvironmental target of silibinin in primary lung tumors and brain metastasis. Finally, by unraveling the selective vulnerability of silibinin-treated tumor cells to drugs using CRISPR-based chemosensitivity screenings (e.g., the hexosamine biosynthesis pathway inhibitor azaserine), we illustrate how the therapeutic use of silibinin against targetable weaknesses might be capitalized in specific lung cancer subtypes (e.g., KRAS/STK11 co-mutant tumors). Forthcoming studies should take up the challenge of developing silibinin and/or next-generation silibinin derivatives as novel lung cancer-preventive and therapeutic biomolecules.

Targeting key transcriptional factor STAT3 in colorectal cancer

In developed countries, colorectal cancer (CRC) is the fourth most common cancer and the second leading cause of malignant-related deaths. CRC is treatable cancer when diagnosed early; however, diagnosis at the advanced stage is associated with a poor prognosis. Although chemotherapy is generally very promising, STAT3 protein which is overexpressed and persistently activated in CRC cells is observed to be the major contributor of chemoresistance development. It has been shown to play a prominent and pathogenic role in CRC initiation, progression, and metastasis. While over the past few years, research has been focused on STAT3 which is expressed at the center of various oncogenic pathways. This review is a discussion of the oncogenic role of STAT3 in CRC and potential therapeutic STAT3 inhibitors and analogs used to control and treat CRC.

Targeting Imd pathway receptor in Drosophila melanogaster and repurposing of phyto-inhibitors: structural modulation and molecular dynamics

Dysbiosis is a major cause of disease in an individual, generally initiated in the gastrointestinal tract. The gut, also known as the second brain, constitutes a major role in immune signaling. To study the immunity cascade, the Drosophila model was considered targeting the Imd pathway receptor (2F2L) located in the midgut. This receptor further initiates the immune signaling mechanism influenced by bacteria. To inhibit the Imd pathway, the crystal structure of Imd with PDB: 2F2L was considered for the screening of suitable ligand/inhibitor. In light of our previous studies, repurposing of anti-diabetic ligands from the banana plant namely lupeol (LUP), stigmasterol (STI), β-sitosterol (BST) and umbelliferone (UMB) were screened. This study identifies the potential inhibitor along with the tracheal toxin (TCT), a major peptidoglycan constituent of microbes. The molecular docking and molecular dynamics simulation of complexes 2F2L-MLD, 2F2L- CAP, 2F2L-LUP, 2F2L-BST, 2F2L-STI and 2F2L-UMB elucidates the intermolecular interaction into the inhibitory property of ligands. The results of this study infer LUP and UMB as better ligands with high stability and functionality among the screened candidates. This study provides insights into the dysbiosis and its amelioration by plant-derived molecules. The identified drugs (LUP & UMB) will probably act as an inhibitor against microbial dysbiosis and other related pathogenesis (diabetes and diabetic neuropathy). Further, this study will widen avenues in fly biology research and which could be used as a therapeutic model in the rapid, reliable and reproducible screening of phytobiologics in complementary and alternative medicine for various lifestyle associated complications.Communicated by Ramaswamy H. Sarma.

Noncanonical pS727 post translational modification dictates major STAT3 activation and downstream functions in breast cancer

Activation of STAT3 via Y705-phosphorylation is well documented across multiple cancer types and thus forms the basis of canonical pathway to judge STAT3 activation. Recently, important roles of two other post translational modification (PTM) sites, i.e. S727-phosphorylation and K685-acetylation, leading to STAT3 activation are reported. However, their critical mode of function in controlling STAT3 dimerization and signaling, independent of canonical activation remains elusive. Therefore, to understand the functional relevance of each STAT3 PTMs in breast cancer (BC), cell models are developed by stable overexpression of PTM-site specific point mutants, i.e. Y705F, S727A or K685R, in a 3'UTR-STAT3 knockdown BC cell background. Results using this model system reveal novel findings showing that phosphorylation at S727 can lead to STAT3 activation independent of phosphoY705. We also demonstrate that loss of pS727 or K685ac significantly affects functional phenotypes such as cell survival and proliferation as well as downstream transcriptional activity (Twist 1, Socs3, c-Myc, Bcl-1 and Mcl-1) of STAT3. Thereafter, by utilizing a BRET biosensor for measuring STAT3 phosphorylation in live cells, a crucial role of pS727 in dictating STAT3 activation and homodimerization formation is uncovered. Further by performing retrospective IHC analysis of total and phospho-forms of STAT3 in a cohort of 76 triple negative breast cancer (TNBC) patient samples, a significant dominant expression of phosphoS727 over phosphoY705 PTM (p < 0.001) is found in STAT3 positive cases. We also focus on validating known STAT3 inhibitor molecules for their action against both pY705 and pS727 activation. This study for the first time demonstrates that an anti-helminth drug compound, Niclosamide, is capable of inactivating both phospho-PTM sites on STAT3 and exhibits excellent anticancer efficacy in preclinical TNBC tumour model.

Case studies on computer-based identification of natural products as lead molecules

The development and application of computer-aided drug design/discovery (CADD) techniques (such as structured-base virtual screening, ligand-based virtual screening and neural networks approaches) are on the point of disintermediation in the pharmaceutical drug discovery processes. The application of these CADD methods are standing out positively as compared to other experimental approaches in the identification of hits. In order to venture into new chemical spaces, research groups are exploring natural products (NPs) for the search and identification of new hits and more efficient leads as well as the repurposing of approved NPs. The chemical space of NPs is continuously increasing as a result of millions of years of evolution of species and these data are mainly stored in the form of databases providing access to scientists around the world to conduct studies using them. Investigation of these NP databases with the help of CADD methodologies in combination with experimental validation techniques is essential to identify and propose new drug molecules. In this chapter, we highlight the importance of the chemical diversity of NPs as a source for potential drugs as well as some of the success stories of NP-derived candidates against important therapeutic targets. The focus is on studies that applied a healthy dose of the emerging CADD methodologies (structure-based, ligand-based and machine learning).

Structure-based virtual screening, biological evaluation and biophysical study of novel Mcl-1 inhibitors

Aim: Targeting the protein-protein interactions (PPIs) associated with Mcl-1 has become a promising therapeutic approach for cancer. Herein, we reported the discovery of novel Mcl-1 inhibitors using an integrated computational approach. Results: Among 30 virtual screening hits, five compounds show inhibitory activities against Mcl-1. The most potent inhibitors M02 (K _i  = 5.4 μM) and M08 (K_i = 0.53 μM) exhibit good selectivity against Bcl-2 and Bcl-xL. Compound M08 exhibits anti-proliferation activity and induces caspase-3 activation in Jurkat cancer cells. Moreover, ¹H⁄¹⁵N HSQC NMR experiments suggested that compound M08 likely binds in the P2 pocket of Mcl-1 and engages R263 in a salt bridge. Conclusion: Our study provides a good starting point for future discovery of more potent Mcl-1 selective inhibitors.

Synergistic Effect of Chlorogenic Acid and Caffeic Acid with Fosfomycin on Growth Inhibition of a Resistant Listeria monocytogenes Strain

Listeria monocytogenes, a human foodborne pathogen that causes listeriosis with high-rate mortality, has been reported to be resistant to commonly used antibiotics. New antibiotics or cocktails of existing antibiotics with synergistic compounds are in high demand for treating this multi-drug-resistant pathogen. Fosfomycin is one of the novel and promising therapeutic antibiotics for the treatment of listeriosis. However, some L. monocytogenes strains with the FosX gene were recently reported to survive from the fosfomycin treatment. This work aims to identify FosX inhibitors that can revive fosfomycin in treating resistant L. monocytogenes. Since structures and activities of the FosX protein in L. monocytogenes have been well studied, we used an integrated computational and experimental approach to identify FosX inhibitors that show synergistic effect with fosfomycin in treating resistant L. monocytogenes. Specifically, automated ligand docking was implemented to perform virtual screening of the Indofine natural-product database and FDA-approved drugs to identify potential inhibitors. An in vitro bacterial growth inhibition test was then utilized to verify the effectiveness of identified compounds combined with fosfomycin in inhibiting the resistant L. monocytogenes strains. Two phenolic acids, i.e., caffeic acid and chlorogenic acid, were predicted as high-affinity FosX inhibitors from the ligand-docking platform. Experiments with these compounds indicated that the cocktail of either caffeic acid (1.5 mg/mL) or chlorogenic acid (3 mg/mL) with fosfomycin (50 mg/L) was able to significantly inhibit the growth of the pathogen. The finding of this work implies that the combination of fosfomycin with either caffeic acid or chlorogenic acid is of potential to be used in the clinical treatment of Listeria infections.

The design and development of covalent protein-protein interaction inhibitors for cancer treatment

Protein-protein interactions (PPIs) are central to a variety of biological processes, and their dysfunction is implicated in the pathogenesis of a range of human diseases, including cancer. Hence, the inhibition of PPIs has attracted significant attention in drug discovery. Covalent inhibitors have been reported to achieve high efficiency through forming covalent bonds with cysteine or other nucleophilic residues in the target protein. Evidence suggests that there is a reduced risk for the development of drug resistance against covalent drugs, which is a major challenge in areas such as oncology and infectious diseases. Recent improvements in structural biology and chemical reactivity have enabled the design and development of potent and selective covalent PPI inhibitors. In this review, we will highlight the design and development of therapeutic agents targeting PPIs for cancer therapy.

Signal Transducer and Activator of Transcription Protein 3 (STAT3): An Update on its Direct Inhibitors as Promising Anticancer Agents

BACKGROUND

Since Signal Transducer and Activator of Transcription 3 (STAT3) is a transcription factor which plays an important role in multiple aspects of cancer, including progression and migration, and it is constitutively activated in various human tumors, STAT3 inhibition has emerged as a validated strategy for the treatment of several malignancies. The aim of this review is to provide an update on the identification of new promising direct inhibitors targeting STAT3 domains, as potential anticancer agents.

METHODS

A thorough literature search focused on recently reported STAT3 direct inhibitors was undertaken. We considered the relevant developments regarding the STAT3 domains, which have been identified as potential drug targets.

RESULTS

In detail, 135 peer-reviewed papers and 7 patents were cited; the inhibitors we took into account targeted the DNA binding domain (compounds were grouped into natural derivatives, small molecules, peptides, aptamers and oligonucleotides), the SH2 binding domain (natural, semi-synthetic and synthetic compounds) and specific residues, like cysteines (natural, semi-synthetic, synthetic compounds and dual inhibitors) and tyrosine 705.

CONCLUSION

The huge number of direct STAT3 inhibitors recently identified demonstrates a strong interest in the investigation of this target, although it represents a challenging task considering that no drug targeting this enzyme is currently available for anticancer therapy. Notably, many studies on the available inhibitors evidenced that some of them possess a dual mechanism of action.

PTPRT epigenetic silencing defines lung cancer with STAT3 activation and can direct STAT3 targeted therapies

Signal Transducers and Activators of Transcription-3 (STAT3), a potent oncogenic transcription factor, is constitutively activated in lung cancer, but mutations in pathway genes are infrequent. Protein Tyrosine Phosphatase Receptor-T (PTPRT) is an endogenous inhibitor of STAT3 and PTPRT loss-of-function represents one potential mechanism of STAT3 hyperactivation as observed in other malignancies. We determined the role of PTPRT promoter methylation and sensitivity to STAT3 pathway inhibitors in non-small cell lung cancer (NSCLC). TCGA and Pittsburgh lung cancer cohort methylation data revealed hypermethylation of PTPRT associated with diminished mRNA expression in a subset of NSCLC patients. We report frequent hypermethylation of the PTPRT promoter which correlates with transcriptional silencing of PTPRT and increased STAT3 phosphorylation (Y705) as determined by methylation-specific PCR (MSP) and real time quantitative reverse transcription (RT)-PCR in NSCLC cell lines. Silencing of PTPRT using siRNA in H520 lung cancer cell line resulted in increased pSTAT3_Tyr705 and upregulation of STAT3 target genes such as Cyclin D1 and Bcl-X_L expression. We show this association of PRPRT methylation with upregulation of the STAT3 target genes Cyclin D1 and Bcl-X_L in patient derived lung tumour samples. We further demonstrate that PTPRT promoter methylation associated with different levels of pSTAT3_Ty705 in lung cancer cell lines had selective sensitivity to STAT3 pathway small molecule inhibitors (SID 864,669 and SID 4,248,543). Our data strongly suggest that silencing of PTPRT by promoter hypermethylation is an important mechanism of STAT3 hyperactivation and targeting STAT3 may be an effective approach for the development of new lung cancer therapeutics.

Inhibition of Stat3 Signaling Pathway by Natural Product Pectolinarigenin Attenuates Breast Cancer Metastasis

Background: Breast cancer is the most common female cancer with considerable metastatic potential, which urges the need for developing novel potential drug candidate to inhibit tumor metastasis. Signal transducer and activator of transcription 3 (Stat3) have critical roles in cancer growth and metastasis and have been confirmed as a promising anticancer target. Here, we report our finding with pectolinarigenin, a flavonoid compound isolated from the aerial parts of Cirsium chanroenicum.

Methods: The role of Pec. in cell proliferation, cell apoptosis, and cell migration and invasion in three breast cancer cells (4T1, MDA-MB-231, MCF-7) was investigated. Cell proliferation was determined by MTT assay, cell apoptosis was determined by flow cytometry, and protein expression was detected by western blotting. Tumor xenograft mice model and breast tumor metastasis model in vivo were built to further assess the effects of Pec. on 4T1 cells.

Results: Intraperitoneal administrations of pectolinarigenin significantly inhibited breast cancer metastasis to lungs without affecting the tumor growth of incubated 4T1 breast cancer cells. Pectolinarigenin could also recruit CD8⁺ T cells to mediate tumor immune response. Furthermore, pectolinarigenin markedly impaired cancer cell migration and invasion by down-regulating phosphorylated-Stat3, and expression of matrix metalloproteinase (MMP)-2, MMP-9, while up-regulating the expression of TIMP2. We also found that pectolinarigenin inhibited breast cancer cell proliferation and induced apoptosis via mitochondrial-related apoptosis pathway, reduced mitochondrial membrane potential and the expression of Bcl-2, increased expression of Bax, and cleaved caspase-3 as well as disturbed the ROS generation.

Conclusions: Pectolinarigenin might potentially be a candidate for metastasis of breast cancer by mediating Stat3 pathway.

Neuroprotection induced by Navβ2‑knockdown in APP/PS1 transgenic neurons is associated with NEP regulation

Voltage‑gated sodium channel β2 (Navβ2), as an unconventional substrate of β‑site amyloid precursor protein cleaving enzyme 1, is involved in regulating the neuronal surface expression of sodium channels. A previous study demonstrated that knockdown of Navβ2 protected neurons and induced spatial cognition improvement by partially reducing pathological amyloidogenic processing of amyloid precursor protein (APP) in aged APP/presenilin 1 (PS1) transgenic mice. The present study aimed to investigate whether Navβ2 knockdown altered APP metabolism via regulation of the Aβ‑degrading enzyme neprilysin (NEP). APPswe/PS1ΔE9 mice (APP/PS1 transgenic mice with a C57BL/6J genetic background) carrying a Navβ2‑knockdown mutation (APP/PS1/Navβ2‑kd) or without Navβ2 knockdown (APP/PS1) were used for cell culture and further analysis. The present results demonstrated that in APP/PS1 mouse‑derived neurons, Navβ2 knockdown partially reversed the reduction in pathological APP cleavage, and the recovery of neurite extension and neuron area. Additionally, Navβ2 knockdown increased NEP activity and levels, and the levels of intracellular domain fragment binding to the NEP promoter. The present findings suggested that knockdown of Navβ2 reversed the APP/PS1 mutation‑induced deficiency in amyloid β degradation by regulating NEP.

Aptamer-integrated α-Gal liposomes as bispecific agents to trigger immune response for killing tumor cells

A novel bispecific α-Gal liposome was constructed by self-assembling AS1411 aptamers into the α-Gal containing liposomes. The α-Gal liposomes were prepared using cell membranes of red blood cells from rabbit, which are composed of cholesterol, phospholipids, and α-Gal glycolipids. AS1411 is a DNA aptamer with high specificity and affinity for nucleolin and could integrate into liposomes by the modification of cholesterol. The bispecific α-Gal liposomes surface-functionalized by α-Gal and AS1411 aptamer could recognize anti-Gal antibodies and nucleolin overexpressed by tumor cells simultaneously, followed by activating the immune system to attack the tumor cells, resulting in the lysis of the tumor cells by antibody dependent cell-mediated cytotoxicity. Under simulated tumor environment, the lysis rate of MCF-7 cells treated by the AS1411 modified α-Gal liposomes drastically increased compared to the liposomes without AS1411 aptamer. This study suggests that the AS1411 modified α-Gal liposomes can recognize nucleolin-overexpressing tumor cells selectively, subsequently improve the effect of the immunotherapy with high specificity. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 1176-1183, 2019.

Aurone derivatives as Vps34 inhibitors that modulate autophagy

We report in this study the identification of a natural product-like antagonist (1a) of Vps34 as a potent autophagy modulator via structure-based virtual screening. Aurone derivative 1a strongly inhibited Vps34 activity in cell-free and cell-based assays. Significantly, 1a prevents autophagy in human cells induced either by starvation or by an mTOR inhibitor. In silico modeling and kinetic data revealed that 1a could function as an ATP-competitive inhibitor of Vps34. Moreover, it suppressed autophagy in vivo and without inducing heart or liver damage in mice. 1a could be utilized as a new motif for more selective and efficacious antagonists of Vps34 for the potential treatment of autophagy-related human diseases.

Butoxy Mansonone G Inhibits STAT3 and Akt Signaling Pathways in Non-Small Cell Lung Cancers: Combined Experimental and Theoretical Investigations

Epidermal growth factor receptor (EGFR) is the key molecular target for non-small cell lung cancer (NSCLC) due to its major contribution to complex signaling cascades modulating the survival of cancer cells. Targeting EGFR-mediated signaling pathways has been proved as a potential strategy for NSCLC treatment. In the present study, mansonone G (MG), a naturally occurring quinone-containing compound, and its semi-synthetic ether derivatives were subjected to investigate the anticancer effects on human NSCLC cell lines expressing wild-type EGFR (A549) and mutant EGFR (H1975). In vitro cytotoxicity screening results demonstrated that butoxy MG (MG3) exhibits the potent cytotoxic effect on both A549 (IC₅₀ of 8.54 μM) and H1975 (IC₅₀ of 4.21 μM) NSCLC cell lines with low toxicity against PCS201-010 normal fibroblast cells (IC₅₀ of 21.16 μM). Western blotting and flow cytometric analyses revealed that MG3 induces a caspase-dependent apoptosis mechanism through: (i) inhibition of p-STAT3 and p-Akt without affecting upstream p-EGFR and (ii) activation of p-Erk. The 500-ns molecular dynamics simulations and the molecular mechanics combined with generalized Born surface area (MM/GBSA)-based binding free energy calculations suggested that MG3 could possibly interact with STAT3 SH2 domain and ATP-binding pocket of Akt. According to principal component analysis, the binding of MG3 toward STAT3 and Akt dramatically altered the conformation of proteins, especially the residues in the active site, stabilizing MG3 mainly through van der Waals interactions.

Structure-Based Discovery of a Selective KDM5A Inhibitor that Exhibits Anti-Cancer Activity via Inducing Cell Cycle Arrest and Senescence in Breast Cancer Cell Lines

Breast cancer is the one of the most frequent causes of female cancer mortality. KDM5A, a histone demethylase, can increase the proliferation, metastasis, and drug resistance of cancers, including breast cancer, and is thus an important therapeutic target. In the present work, we performed hierarchical virtual screening towards the KDM5A catalytic pocket from a chemical library containing 90,000 compounds. Using multiple biochemical methods, the cyclopenta[c]chromen derivative 1 was identified as the top candidate for KDM5A demethylase inhibitory activity. Compared with the well-known KDM5 inhibitor CPI-455 (18), 1 exhibited higher potency against KDM5A and much higher selectivity for KDM5A over both KDM4A and other KDM5 family members (KDM5B and KDM5C). Additionally, compound 1 repressed the proliferation of various KDM5A-overexpressing breast cancer cell lines. Mechanistically, 1 promoted accumulation of p16 and p27 by blocking KDM5A-mediated H3K4me3 demethylation, leading to cell cycle arrest and senescence. To date, compound 1 is the first cyclopenta[c]chromen-based KDM5A inhibitor reported, and may serve as a novel motif for developing more selective and efficacious pharmacological molecules targeting KDM5A. In addition, our research provides a possible anti-cancer mechanism of KDM5A inhibitors and highlights the feasibility and significance of KDM5A as a therapeutic target for KDM5A-overexpressing breast cancer.

Astragalus polysaccharide from Astragalus Melittin ameliorates inflammation via suppressing the activation of TLR-4/NF-κB p65 signal pathway and protects mice from CVB3-induced virus myocarditis

Inflammation plays a crucial role in regulating cardiomyopathy and injuries of coxsackievirus B3 (CVB3)-induced viral myocarditis (VM). It has been reported that Astragalus polysaccharide (AP) from Astragalus Melittin could inhabit inflammatory gene expression under a variety of pathological conditions. However, the functional roles of AP in CVB3-induced VM still remain unknown. Here, we found that AP significantly enhanced survival for CVB3-induced mice. AP protected the mice against CVB3-induced myocardial injuries characterized by the increased body weight and depressed serum level of creatine kinase-MB (CK-MB), aspartate transaminases (AST) and lactate dehydrogenase (LDH), enhanced left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS). At the pathological level, AP ameliorated the mice against CVB3-induced myocardial damage, dilated cardiomyopathy and chronic myocardial fibrosis. We subsequently found that AP significantly suppressed CVB3-induced expression of inflammation marker (IL-1β, IL-6, TNF-α, INF-γ and MCP-1) in heart. Furthermore, we confirmed that AP suppressed the CVB3-induced expression of TLR-4 and phosphorylated NF-κB p65 in heart. Taken together, the data suggest that AP protects against CVB3-induced myocardial damage and inflammation, which may partly attribute to the regulation of TLR-4/NF-κB p65 signal pathway, moreover, suppressive effect of AP on CVB3-induced activation of TLR-4/NF-κB p65 signal was TNF-α-independent.

In silico polypharmacology of natural products

Natural products with polypharmacological profiles have demonstrated promise as novel therapeutics for various complex diseases, including cancer. Currently, many gaps exist in our knowledge of which compounds interact with which targets, and experimentally testing all possible interactions is infeasible. Recent advances and developments of systems pharmacology and computational (in silico) approaches provide powerful tools for exploring the polypharmacological profiles of natural products. In this review, we introduce recent progresses and advances of computational tools and systems pharmacology approaches for identifying drug targets of natural products by focusing on the development of targeted cancer therapy. We survey the polypharmacological and systems immunology profiles of five representative natural products that are being considered as cancer therapies. We summarize various chemoinformatics, bioinformatics and systems biology resources for reconstructing drug-target networks of natural products. We then review currently available computational approaches and tools for prediction of drug-target interactions by focusing on five domains: target-based, ligand-based, chemogenomics-based, network-based and omics-based systems biology approaches. In addition, we describe a practical example of the application of systems pharmacology approaches by integrating the polypharmacology of natural products and large-scale cancer genomics data for the development of precision oncology under the systems biology framework. Finally, we highlight the promise of cancer immunotherapies and combination therapies that target tumor ecosystems (e.g. clones or 'selfish' sub-clones) via exploiting the immunological and inflammatory 'side' effects of natural products in the cancer post-genomics era.

Andrographolide derivative as STAT3 inhibitor that protects acute liver damage in mice

Sustained activation of the Janus kinase-signal transducers and activators of transcription (JAK-STAT) pathway contributed to the progression of cancer and liver diseases. STAT3 signaling inhibitor has been extensively investigated for pharmacological use. We synthesized a series of andrographolide derivatives, and characterized their activity against STAT3 signaling pathway both in vitro and in the CCl₄-induced acute liver damage mice model. Among these derivatives, compound 24 effectively inhibited phosphorylation and dimerization of STAT3 but not its DNA binding activity. Compound 24 significantly ameliorated carbon tetrachloride-induced acute liver damage in vivo without changing mice body weight. Treatment with 24 attenuated hepatic pathologic damage and promoted hepatic proliferation and activation of STAT3. Compound 24 inhibited elevated expression of α-smooth muscle actin and serum pro-inflammatory cytokines downstream of STAT3 but not those factors that are regulated by NF-κB or SMADs. In summary, our results suggest that compound 24 may serve as a potential therapeutic agent for the treatment of hepatic damage or a liver protection agent via regulating STAT3 activation.

Lycorine Displays Potent Antitumor Efficacy in Colon Carcinoma by Targeting STAT3

Signal transducer and activator of transcription 3 (STAT3) is an attractive therapeutic target for cancer treatment. In this study, we identify lycorine is an effective inhibitor of STAT3, leading to repression of multiple oncogenic processes in colon carcinoma. Lycorine selectively inactivates phospho-STAT3 (Tyr-705), and subsequent molecular docking uncovers that lycorine directly binds to the SH2 domain of STAT3. Consequently, we find that lycorine exhibits anti-proliferative activity and induces cell apoptosis on human colorectal cancer (CRC) in vitro. Lycorine induces the activation of the caspase-dependent mitochondrial apoptotic pathway, as indicated by activation of caspase and increase of the ratio of Bax/Bcl-2 and mitochondrial depolarization. Overexpressing STAT3 greatly blocks these effects by lycorine in CRC cells. Finally, lycorine exhibits a potential therapeutic effect in xenograft colorectal tumors by targeting STAT3 without observed toxicity. Taken together, the present study indicates that lycorine acts as a promising inhibitor of STAT3, which blocks tumorigenesis in colon carcinoma.

Purification, characterization and anti-fatigue activity of polysaccharide fractions from okra (Abelmoschus esculentus (L.) Moench)

The aim of this study was to investigate the anti-fatigue activity of polysaccharide fractions from Abelmoschus esculentus (L.) Moench (AE) in mice. After crude polysaccharide (CAEP) was extracted from AE and purified by DEAE cellulose-52 column, two polysaccharide fractions (AEP-1 and AEP-2) were obtained. The structural analysis suggested that AEP-1 and AEP-2 were a RG-I polysaccharide and an AG-II polysaccharide, respectively. According to the results of the weight-loaded swimming test, compared with the negative control group, the CAEP, AEP-1 and AEP-2 treatment groups could prolong the swimming time, decrease serum urea nitrogen (SUN) and blood lactic acid (BLA), and increase hepatic glycogen (HG) and muscle glycogen (MG), which indicated that okra polysaccharides have an effective anti-fatigue activity. Furthermore, our study exhibited the anti-fatigue mechanism of okra polysaccharide was correlated with retarding the accumulation of creatine kinase (CK) and lactate dehydrogenase (LDH) in serum, and enhancing succinate dehydrogenase (SDH), adenosine triphosphate (ATP) and adenosine triphosphatase (ATPase) levels. In addition, the anti-fatigue activity of AEP-1 was stronger than that of AEP-2, and significantly better than that of CAEP. Therefore, AEP-1 and AEP-2 may be the main active anti-fatigue functional substances of AE.

Assessing the intracellular fate of rhodium(ii) complexes

Rhodium(ii)-fluorophore conjugates have strong rhodium-based fluorescence quenching that can be harnessed to report on a conjugate's cellular uptake and the intracellular decomposition rate. Information gleened from this study allowed the design of an improved STAT3 metalloinhibitor.

Cardioprotection of Sheng Mai Yin a classic formula on adriamycin induced myocardial injury in Wistar rats

BACKGROUND

Sheng Mai Yin (SMY), a well-known Chinese herbal medicine, is widely used to treat cardiac diseases characterized by the deficiency of Qi and Yin syndrome in China. SMY-based treatment has been derived from Traditional Chinese Medicine (TCM), officially recorded in the Chinese Pharmacopoeia.

PURPOSE

We aimed to clarify whether SMY attenuates myocardial injury induced by adriamycin in Wistar rats with chronic heart failure (CHF).

METHODS

To quantify ginsenoside Rg1, ophiopogonin D, ophiopogonin D', schisandrin by HPLC. To establish CHF animal model, adriamycin was intraperitoneally injected in Wistar rats for 7 weeks at a dose of 2 mg/kg body weight. Overall, 180 rats were randomly assigned to six groups: control, CHF model, captopril (positive control), high dose (HSMY), medium dose (MSMY), and low dose (LSMY). Experimental rats were fed 0.625 mg/kg captopril and 90 mg/kg, 45 mg/kg, and 22.5 mg/kg SMY, respectively, over 7 weeks. The inflammatory cytokines TNF-α and IL-6 were measured using ELISA. Matrix metalloproteinases (MMPs) were identified using immunohistochemistry (IHC). Both IHC and RT-PCR were used for quantification of COL-IV expression levels in the heart tissues. Scanning electron microscopy (SEM) was used for the visualization of myocardium morphology.

RESULTS

The concentration of ginsenoside Rg1, ophiopogonin D, ophiopogonin D' and schisandrin in SMY was found to be 25.63 ± 3.42 mg, 11.00 ± 1.17 mg, 7.02 ± 0.51 mg, and 25.31 ± 4.28 mg per gram of SMY, respectively. Compared with CHF model group, TNF-α levels were significantly lower (p < .01) in the four drug-administered groups. Moreover, except in the SYM low dose group, IL-6 levels in the other 3 drug-administered groups were also significantly reduced (p < .01). COL-IV expression was also significantly reduced on treatment with high SYM dose (p < .05). IHC results confirmed that SMY and captopril significantly reduced MMPs expression in the heart.

CONCLUSION

SMY could control or slow CHF progression by suppressing pathological changes in the myocardium in CHF models. This could be attributed at least partly to the downregulation of IL-6 and TNF-α and inhibition of overexpression of MMPs and COL-IV, which significantly relieved the cardiac-linked pathologies, decreased the risk of myocardial fibrosis, and inhibited cardiac remodeling. These findings suggested that SMY and captopril have similar efficacy for the treatment of adriamycin-induced myocardial injury. In addition, Chinese herbal preparation SMY may play a role in the treatment of cardiac diseases.

Inhibition of the p53/hDM2 protein-protein interaction by cyclometallated iridium(III) compounds

Inactivation of the p53 transcription factor by mutation or other mechanisms is a frequent event in tumorigenesis. One of the major endogenous negative regulators of p53 in humans is hDM2, a ubiquitin E3 ligase that binds to p53 causing proteasomal p53 degradation. In this work, a library of organometallic iridium(III) compounds were synthesized and evaluated for their ability to disrupt the p53/hDM2 protein-protein interaction. The novel cyclometallated iridium(III) compound 1 [Ir(eppy)₂(dcphen)](PF₆) (where eppy = 2-(4-ethylphenyl)pyridine and dcphen = 4, 7-dichloro-1, 10-phenanthroline) blocked the interaction of p53/hDM2 in human amelanotic melanoma cells. Finally, 1 exhibited anti-proliferative activity and induced apoptosis in cancer cell lines consistent with inhibition of the p53/hDM2 interaction. Compound 1 represents the first reported organometallic p53/hDM2 protein-protein interaction inhibitor.