Pharmacoinformatics approach for the screening of Kovidra (Bauhinia variegata) phytoconstituents against tumor suppressor protein in triple negative breast cancer

Globally, 2.3 million women were diagnosed with breast cancer, with 6,85000 mortalities in year 2021; making it the world's most prevalent cancer. This growing global burden necessitates a new treatment option, and plant-based medicines offers a promising alternative to conventional cancer treatment. In this work, screening of phytoconstituents of an indigenous therapeutic plant, Bauhinia variegata carried out for potential regulator of tumor suppressor protein p53. Here, an in-silico analysis was employed to develop more effective, pharmaceutically potent small drug-like compounds that target tumor suppressor protein p53. The methanol and aqueous powdered extracts of Bauhinia variegata were prepared and phytochemically evaluated along with antioxidant property evaluation. The LC50 of methanol (325.33 µg/ml) and aqueous extract (361.15 µg/ml) showed their cytotoxic characteristics. Further, GCMS analysis of both the extracts reveals total 57 secondary metabolites. Among these, four lead compounds; compound 1, compound 2, compound 3 and compound 4 were found to have the highest binding ability (-8.15 to -5.40 kcal/mol) with p53. MD simulation and binding free energy validates these findings with highest binding free energy (-67.09 ± 4.87 kcal/mol) towards p53 by the lead phytocompound 2. Selected compounds exhibit excellent pharmacokinetic features and drug-like characteristics. The acute toxicity (LD50) values of the lead phytocompounds ranges from 670 mg/kg to 3100 mg/kg, with toxicity classes of IV and V. As a result, these druggable phytochemicals could serve as potential lead applicants for triple negative breast cancer treatment. However, more in vitro and in vivo research is planned to produce future breast cancer medicine. HIGHLIGHTSScreening of phytoconstituents of an indigenous therapeutic plant, Bauhinia variegata, for potential regulator of tumor suppressor protein p53.The LC50 of methanol (325.33µg/ml) and aqueous extract (361.15µg/ml) showed their cytotoxic characteristics.GCMS analysis of both the extracts reveals total 57 secondary metabolites. Among these, four lead compounds were found to have the highest binding affinity (-8.153 to -5.401 kcal/mol) with tumor suppressor protein p53.MD simulation along with the Prime MM/GBSA binding free energy validates this discovery with highest binding free energy (-67.09 ± 4.87 kcal/mol) towards p53 by the lead compound 2.The acute toxicity (LD50) values of the lead phytocompounds ranges from 670 mg/kg to 3100 mg/kg, with toxicity classes of IV and V.As a result, these druggable phytochemicals could serve as potential lead applicants for triple negative breast cancer treatment.Communicated by Ramaswamy H. Sarma.

Dual inhibition of cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX) by resveratrol derivatives in cancer therapy: in silico approach

In a number of human cancers, both cycloxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX) are up-regulated and co-expressed, promoting cancer cell proliferation and angiogenesis. Resveratrol (3,4',5-trihydroxy-trans-stilbene) is a natural polyphenolic phytoalexin found in a variety of plants that influences various signal-transduction pathways which control apoptosis, cell growth and cell division, metastasis, angiogenesis and inflammation, and has an impact on cancer stages ranging from initiation to progression. In this work, molecular docking and molecular dynamics simulation method are employed to design resveratrol derivatives for COX-2 and 5-LOX enzymes. By attaching several functional groups on four different places of the resveratrol scaffold, the R group enumeration approach was employed to build four libraries of resveratrol derivatives. Thus, R group enumeration is done to focus on the enhancement of potency of compounds and other chemical characteristics like solubility. Drug-like filters such as REOS 1, 2, 3 and PAINS were applied to the libraries, generating a total of 5557 compounds. Drug-like filters such as REOS and PAINS-1, 2 and 3 were applied to the libraries, generating a total of 5557 compounds. All of these compounds were docked with both enzymes using the Glide SP and XP docking methods. Enrichment calculations were performed using 40 compounds from XP docking along with resveratrol, and 1000 decoy compounds from the DUD-E database to validate the docking protocol. The stability of the complexes was further studied using molecular dynamics simulation, radius of gyration, MM/GBSA, H bond monitoring and electrostatic potential surface (EPS). ADMET properties of compounds were studied using SwissADME and pkCSM server.Communicated by Ramaswamy H. Sarma.

An in-silico investigation and network pharmacology based approach to explore the anti-breast-cancer potential of Tecteria coadunata (Wall.) C. Chr

Uncontrolled cell proliferation is a common definition of cancer. After lung carcinoma, breast neoplasm is the second-most prevalent kind of cancer. The majority of breast cancer cells and healthy breast cells both have receptors for circulating oestrogen and progesterone. In order to promote the development and division of cancer cells, oestrogen and progesterone bind to the receptors and may collaborate with growth factors (such as oncogenes and mutant tumour suppressor genes). As per the literature, Tecteria coadunata (Wall.) C. Chr. has anticancer, antioxidant and anti-inflammatory potential. After the hydroalcoholic extraction of this rhizome, total of 200 phytochemicals were retrieved from HR-LCMS analysis. In this current study, Network pharmacology was carried out to explore the rationale of Tecteria coadunata (Wall.) C. Chr. by using different database using Cytoscape software. The network depicted the interaction of Bioactives with their targets and their association with several disease, especially breast cancer. Tecteria coadunata (Wall.) C. Chr. has offered new relationship with variety of genes and its applications in different types of breast cancers. Further Gene Ontology was carried out and it showed key targets were TP53, BRCA2, PGR and CHEK 2. Further Signalling pathways were also enriched. Flex-X software was used for molecular docking studies, and it verified that Dopaxanthin, Dantrolene and Orotidin shows the highest binding affinities with key targets. Additionally, Pharmacokinetic analysis revealed that all top three lead compounds which follows the Lipinski Rule (Rule of three) without interrupting the conditions of bioavailability with minimal toxicity.Communicated by Ramaswamy H. Sarma.

Exploring Potential Non-Steroidal Aromatase Inhibitors for Therapeutic Application Against Estrogen-Dependent Breast Cancer

BACKGROUND

Breast cancer is one of the most commonly diagnosed cancer types among women worldwide. Cytochrome P450 aromatase (CYP19A1) is an enzyme in vertebrates that selectively catalyzes the biosynthesis of estrogens from androgenic precursors. Researchers have increasingly focused on developing non-steroidal aromatase inhibitors (NSAIs) for their potential clinical use, avoiding steroidal side effects.

OBJECTIVES

The objective of the present work is to search for potential lead compounds from the ZINC database through various in silico approaches.

METHODS

In the present study, compounds from the ZINC database were initially screened through receptor independent-based pharmacophore virtual screening. These screened molecules were subjected to several assessments, such as Lipinski rule of 5, SMART filtration, ADME prediction using SwissADME and lead optimization. Molecular docking was further applied to study the interaction of the filtered compounds with the active site of aromatase. Finally, the obtained hit compounds, consequently represented to be ideal lead candidates, were escalated to the MD simulations.

RESULTS

The results indicated that the lead compounds might be potential anti-aromatase drug candidate.

CONCLUSION

The findings provided a valuable approach in developing novel anti-aromatase inhibitors for the treatment of ER+ breast cancer.

GC-MS profiling of Bauhinia variegata major phytoconstituents with computational identification of potential lead inhibitors of SARS-CoV-2 Mpro

Severe acute respiratory syndrome coronavirus 2 was originally identified in Wuhan city of China in December 2019 and it spread rapidly throughout the globe, causing a threat to human life. Since targeted therapies are deficient, scientists all over the world have an opportunity to develop novel drug therapies to combat COVID-19. After the declaration of a global medical emergency, it was established that the Food and Drug Administration (FDA) could permit the use of emergency testing, treatments, and vaccines to decrease suffering, and loss of life, and restore the nation's health and security. The FDA has approved the use of remdesivir and its analogs as an antiviral medication, to treat COVID-19. The primary protease of SARS-CoV-2, which has the potential to regulate coronavirus proliferation, has been a viable target for the discovery of medicines against SARS-CoV-2. The present research deals with the in silico technique to screen phytocompounds from a traditional medicinal plant, Bauhinia variegata for potential inhibitors of the SARS-CoV-2 main protease. Dried leaves of the plant B. variegata were used to prepare aqueous and methanol extract and the constituents were analyzed using the GC-MS technique. A total of 57 compounds were retrieved from the aqueous and methanol extract analysis. Among these, three lead compounds (2,5 dimethyl 1-H Pyrrole, 2,3 diphenyl cyclopropyl methyl phenyl sulphoxide, and Benzonitrile m phenethyl) were shown to have the highest binding affinity (−5.719 to −5.580 kcal/mol) towards SARS-CoV-2 M^pro. The post MD simulation results also revealed the favorable confirmation and stability of the selected lead compounds with M^pro as per trajectory analysis. The Prime MM/GBSA binding free energy supports this finding, the top lead compound 2,3 diphenyl cyclopropyl methyl phenyl sulphoxide showed high binding free energy (−64.377 ± 5.24 kcal/mol) towards M^pro which reflects the binding stability of the molecule with M^pro. The binding free energy of the complexes was strongly influenced by His, Gln, and Glu residues. All of the molecules chosen are found to have strong pharmacokinetic characteristics and show drug-likeness properties. The lead compounds present acute toxicity (LD50) values ranging from 670 mg/kg to 2500 mg/kg; with toxicity classifications of 4 and 5 classes. Thus, these compounds could behave as probable lead candidates for treatment against SARS-CoV-2. However further in vitro and in vivo studies are required for the development of medication against SARS-CoV-2.

Novel B, C-ring truncated deguelin derivatives reveals as potential inhibitors of cyclin D1 and cyclin E using molecular docking and molecular dynamic simulation

The overexpression of cyclin D1 and cyclin E due to their oncogenic potential and amplification has been associated with a higher mortality rate in many cancers. The deguelin is a natural compound, has shown promising anti-cancer activity by directly binding cyclin D1 and cyclin E and thus suppressing its function. The C7a atomic position of deguelin structure contains a proton that generates stabilized radical, as a result, decomposed deguelin reduces its structural stability and significantly decreases its biological activity. To design deguelin derivatives with the reduced potential side effect, series of B, C-ring truncated derivatives were investigated as cyclin D1 and cyclin E inhibitors. R-group-based enumeration was implemented in the deguelin scaffold using the R-group enumeration module of Schrödinger. Drug-Like filters like, REOS and PAINs series were applied to the enumerated compound library to remove compounds containing reactive functional groups. Further, screened compounds were docked within the ligand-binding cavity of cyclin D1 and cyclin E crystal structure, using Glide SP and XP protocol to obtain docking poses. Enrichment calculations were done using SchrÖdinger software, with 1000 decoy compounds (from DUD.E database) and 60 compounds (XP best poses) along with deguelin, to validate the docking protocol. The receiver operating characteristic (ROC) curve indicates R² = 0.94 for cyclin D1 and R² = 0.79 for cyclin E, suggesting that the docking protocol is valid. Besides, we explored molecular dynamics simulation to probe the binding stability of deguelin and its derivatives within the binding cavity of cyclin D1 and cyclin E structures which are associated with the cyclin D1 and cyclin E inhibitory mechanism.

In Silico Exploration of Phytoconstituents From Phyllanthus emblica and Aegle marmelos as Potential Therapeutics Against SARS-CoV-2 RdRp

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) worldwide has increased the importance of computational tools to design a drug or vaccine in reduced time with minimum risk. Earlier studies have emphasized the important role of RNA-dependent RNA polymerase (RdRp) in SARS-CoV-2 replication as a potential drug target. In our study, comprehensive computational approaches were applied to identify potential compounds targeting RdRp of SARS-CoV-2. To study the binding affinity and stability of the phytocompounds from Phyllanthus emblica and Aegel marmelos within the defined binding site of SARS-CoV-2 RdRp, they were subjected to molecular docking, 100 ns molecular dynamics (MD) simulation followed by post-simulation analysis. Furthermore, to assess the importance of features involved in the strong binding affinity, molecular field-based similarity analysis was performed. Based on comparative molecular docking and simulation studies of the selected phytocompounds with SARS-CoV-2 RdRp revealed that EBDGp possesses a stronger binding affinity (-23.32 kcal/mol) and stability than other phytocompounds and reference compound, Remdesivir (-19.36 kcal/mol). Molecular field-based similarity profiling has supported our study in the validation of the importance of the presence of hydroxyl groups in EBDGp, involved in increasing its binding affinity toward SARS-CoV-2 RdRp. Molecular docking and dynamic simulation results confirmed that EBDGp has better inhibitory potential than Remdesivir and can be an effective novel drug for SARS-CoV-2 RdRp. Furthermore, binding free energy calculations confirmed the higher stability of the SARS-CoV-2 RdRp-EBDGp complex. These results suggest that the EBDGp compound may emerge as a promising drug against SARS-CoV-2 and hence requires further experimental validation.

Pharmacoinformatics-based identification of transmembrane protease serine-2 inhibitors from Morus Alba as SARS-CoV-2 cell entry inhibitors

Transmembrane protease serine-2 (TMPRSS2) is a cell-surface protein expressed by epithelial cells of specific tissues including those in the aerodigestive tract. It helps the entry of novel coronavirus (n-CoV) or Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in the host cell. Successful inhibition of the TMPRSS2 can be one of the crucial strategies to stop the SARS-CoV-2 infection. In the present study, a set of bioactive molecules from Morus alba Linn. were screened against the TMPRSS2 through two widely used molecular docking engines such as Autodock vina and Glide. Molecules having a higher binding affinity toward the TMPRSS2 compared to Camostat and Ambroxol were considered for in-silico pharmacokinetic analyses. Based on acceptable pharmacokinetic parameters and drug-likeness, finally, five molecules were found to be important for the TMPRSS2 inhibition. A number of bonding interactions in terms of hydrogen bond and hydrophobic interactions were observed between the proposed molecules and ligand-interacting amino acids of the TMPRSS2. The dynamic behavior and stability of best-docked complex between TRMPRSS2 and proposed molecules were assessed through molecular dynamics (MD) simulation. Several parameters from MD simulation have suggested the stability between the protein and ligands. Binding free energy of each molecule calculated through MM-GBSA approach from the MD simulation trajectory suggested strong affection toward the TMPRSS2. Hence, proposed molecules might be crucial chemical components for the TMPRSS2 inhibition.

Molecular interaction studies of Deguelin and its derivatives with Cyclin D1 and Cyclin E in cancer cell signaling pathway: The computational approach

Deguelin is a major active ingredient and principal component in several plants and it is a potential molecule to target proteins of cancer cell signaling pathway. As a complex natural extract, deguelin interacts with various molecular targets to exert its anti-tumor properties at nanomolar level. It induces cell apoptosis by blocking anti-apoptotic pathways, while inhibiting tumor cell multiplication and malignant transformation through p27-cyclin-E-pRb-E2F1- cell cycle control and HIF-1alphaVEGF antiangiogenic pathways. In silico studies of deguelin and its derivatives is performed to explore interactions with Cyclin D1 and Cyclin E to understand the molecular insights of derivatives with the receptors. Deguelin and its derivatives are minimized by Avogadro to achieve stable conformation. All docking simulation are performed with AutoDockVina and virtual screening of docked ligands are carried out based on binding energy and number of hydrogen bonds. Molecular dynamics (MD) and Simulation of Cyclin D1 and Cyclin E1 is performed for 100 ns and stable conformation is obtained at 78 ns and 19 ns respectively. Ligands thus obtained from docking studies may be probable target to inhibit cancer cell signaling pathways.

Biofilm inhibition and anti-quorum sensing activity of phytosynthesized silver nanoparticles against the nosocomial pathogen Pseudomonas aeruginosa

Quorum sensing (QS), the communication signaling network, regulates biofilm formation and several virulence factors in Pseudomonas aeruginosa PAO1, a nosocomial opportunistic pathogen. QS is considered to be a challenging target for compounds antagonistic to virulent factors. Biologically synthesized silver nanoparticles (AgNPs) are reported as anti-QS and anti-biofilm drugs against bacterial infections. The present study reports on the synthesis and characterization of Piper betle (Pb) mediated AgNPs (Pb-AgNPs). The anti-QS activity of Pb-AgNPs against Chromobacterium violaceum and the potential effect of Pb-AgNPs on QS-regulated phenotypes in PAO1 were studied. FTIR analysis exhibited that Pb-AgNPs had been capped by phytochemical constituents of Pb. Eugenol is one of the active phenolic phytochemicals in Pb leaves, therefore molecular docking of eugenol-conjugated AgNPs on QS regulator proteins (LasR, LasI and MvfR) was performed. Eugenol-conjugated AgNPs showed considerable binding interactions with QS-associated proteins. These results provide novel insights into the development of phytochemically conjugated nanoparticles as promising anti-infective candidates.

Molecular Modeling, Docking, Dynamics and Simulation of Gefitinib and its Derivatives with EGFR in Non-small Cell Lung Cancer

BACKGROUND

Gefitinib (lressa) is the most prescribed drug, highly effective to treat nonsmall cell lung cancer; primarily it was considered that targeted therapy is a kinase inhibitor. The nonsmall cell lung cancer is caused by mutation in the Epithelial Growth Factor Receptor (EGFR) gene. Iressa works by blocking the EGFR protein that helps the cancer cell growth. EGFR protein has lead to the development of anticancer therapeutics directed against EGFR inhibitor including Gefitinib for non-small cell lung cancer.

METHODS

To explore the interaction between Gefitinib and its derivatives with crystal structure of EGFR to understand the better molecular insights interaction strategies. Molecular modeling of ligands (Gefitinib and its derivatives) was carried out by Avogadro software till atomic angle stable confirmation was obtained. The partial charges for the ligands were assigned as per standard protocol for molecular docking. All docking simulations were performed with AutoDockVina. Virtual screening was carried out based on binding energy and hydrogen bonding affinity. Molecular dynamics (MD) and Simulation EGFR were done using GROMACS 5.1.1 software to explore the interaction stability in a cell.

RESULTS

The stable conformation for EGFR protein trajectories were captured at various time intervals 0-20ns. Few compounds screen based on high affinity as the inhibitor for EGFR may inhibit the cell cycle signaling in non-small cell lung cancer.

CONCLUSION

These result suggested a computer-aided screening approach of Gefitinib derivatives with regard to their binding to EGFR for identifying novel drugs for the treatment of non-small cell lung cancer.

Abstract P5-21-24: Retrospective assessment of treatment patterns and outcomes associated with palbociclib plus letrozole for postmenopausal women with HR+/HER2– advanced breast cancer enrolled in an early access program

Background: The objective of this study was to evaluate treatment patterns and clinical outcomes among patients who received palbociclib in combination with letrozole (P+L) for the treatment of HR+/HER2–advanced breast cancer (ABC) as part of an Expanded Access Program (EAP) in the United States.

Methods: Data were obtained by a retrospective chart review of patients previously enrolled in the EAP. Complete data from time of initial diagnosis of ABC until the date of chart abstraction (end of follow-up), including the post-EAP period, were obtained. Clinical outcomes assessed included clinical benefit rate (CBR), defined as complete response, partial response, or stable disease for ≥24 weeks from P + L initiation, progression free survival (PFS) and overall survival (OS). Survival outcomes were assessed using the Kaplan-Meier statistical analysis.

Results: Data from 126 patients were included in this analysis. Median age was 62.5 years at EAP enrollment, and a majority of patients were Caucasian (83%). Approximately 25% of patients had de novo metastatic disease. A majority of patients had a performance status of ECOG 0 (56%) or 1 (37%) at EAP enrollment. Visceral disease was present in 71% of patients and 16% had bone-only disease. The majority of patients in this cohort from the EAP were heavily pre-treated, having had up to 5 prior lines of therapy in the metastatic setting prior to initiating P + L therapy; nearly 59% received 3+ prior lines before initiating P + L. Only 11% of patients received P + L as their initial regimen for MBC. At the time of the last available record, 12 patients were still on P + L therapy, an average of 21 months after the start of the EAP program. Nearly 80% of patients had prior AI exposure and 69% had prior chemotherapy. CBR was 33% for the overall sample of patients treated with P + L and 22% in those with 3+ prior lines of treatment. Patients with prior AI exposure in the ABC setting (n=100) had a CBR of 27% while those without prior AI exposure had CBR of 58%. Patients with prior chemotherapy (n=87) had a CBR of 28% and those without prior chemotherapy had CBR of 46%. For the entire cohort, 6- and 12-month PFS rates were 40% and 25% respectively; 12- and 24-month OS rates were 66% and 44%, respectively. Patients receiving 3+ lines of prior therapy had 6- and 12-month PFS rates of 28% and 19%, respectively, and 12- and 24-month OS rates of 59% and 34% respectively.

Conclusions: Our results suggest that the majority of patients enrolled in the EAP program derived benefit from receiving treatment with P + L despite multiple prior lines of treatment and prior endocrine-based therapy, including prior AI. These findings further demonstrate the benefit of treatment with palbociclib combination therapy in HR+/HER2– MBC.

Citation Format: Brufsky A, Davis K, Mitra D, Nagar S, McRoy L, Cotter M, Stearns V. Retrospective assessment of treatment patterns and outcomes associated with palbociclib plus letrozole for postmenopausal women with HR+/HER2– advanced breast cancer enrolled in an early access program [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-21-24.

Drug-drug interactions in pharmacologic management of gastroparesis

BACKGROUND

Gastroparesis is a disorder characterized by delayed gastric emptying due to chronic abnormal gastric motility. The treatment of the disease often entails the co-administration of several classes of pharmacological agents. These agents may be metabolized via the same pathway. Inhibition or induction of a shared metabolic pathway leads to change in the systemic levels of prescribed drugs, possibly leading to undesired clinical outcomes.

PURPOSE

This review discusses different pharmacological treatment for gastroparesis patients and describes the potential for drug-drug interactions (DDIs) in some of the combinations that are currently used. Prokinetic agents such as metoclopramide and domperidone are the cornerstone in treatment of gastroparesis. Antiemetic agents such as promethazine and ondansetron are frequently administered to gastroparesis patients to reduce nausea and vomiting. Gastroparesis is prevalent in diabetic patients and therefore antidiabetic agents are also prescribed. Many of these co-administered drugs are metabolized via common drug metabolizing enzymes and this can trigger potential DDIs. The scientific literature was reviewed from the years 1975-2014 for original research articles and reviews that evaluated DDIs in gastroparesis. Many commonly prescribed combinations were predicted to cause potential DDIs in gastroparesis patients. This review will help inform about potential hazardous combinations. This information will hopefully lead to less adverse effects and more successful gastroparesis management.

Intracellular drug concentrations and transporters: measurement, modeling, and implications for the liver

Intracellular concentrations of drugs and metabolites are often important determinants of efficacy, toxicity, and drug interactions. Hepatic drug distribution can be affected by many factors, including physicochemical properties, uptake/efflux transporters, protein binding, organelle sequestration, and metabolism. This white paper highlights determinants of hepatocyte drug/metabolite concentrations and provides an update on model systems, methods, and modeling/simulation approaches used to quantitatively assess hepatocellular concentrations of molecules. The critical scientific gaps and future research directions in this field are discussed.

ITC recommendations for transporter kinetic parameter estimation and translational modeling of transport-mediated PK and DDIs in humans

This white paper provides a critical analysis of methods for estimating transporter kinetics and recommendations on proper parameter calculation in various experimental systems. Rational interpretation of transporter-knockout animal findings and application of static and dynamic physiologically based modeling approaches for prediction of human transporter-mediated pharmacokinetics and drug-drug interactions (DDIs) are presented. The objective is to provide appropriate guidance for the use of in vitro, in vivo, and modeling tools in translational transporter science.

Ceruloplasmin alters intracellular iron regulated proteins and pathways: ferritin, transferrin receptor, glutamate and hypoxia-inducible factor-1α

Ceruloplasmin (Cp) is a ferroxidase important to the regulation of both systemic and intracellular iron levels. Cp has a critical role in iron metabolism in the brain and retina as shown in patients with aceruloplasminemia and in Cp-/-hep-/y mice where iron accumulates and neural and retinal degeneration ensue. We have previously shown that cultured lens epithelial cells (LEC) secrete Cp. The purpose of the current study was to determine if cultured retinal pigmented epithelial cells (RPE) also secrete Cp. In addition, the effects of exogenously added Cp on iron regulated proteins and pathways, ferritin, transferrin receptor, glutamate secretion and levels of hypoxia-inducible factor-1α in the nucleus were determined. Like LEC, RPE secrete Cp. Cp was found diffusely distributed within both cultured LEC and RPE, but the cell membranes had more intense staining. Exogenously added Cp caused an increase in ferritin levels in both cell types and increased secretion of glutamate. The Cp-induced increase in glutamate secretion was inhibited by both the aconitase inhibitor oxalomalic acid as well as iron chelators. As predicted by the canonical view of the iron regulatory protein (IRP) as the predominant controller of cellular iron status these results indicate that there is an increase in available iron (called the labile iron pool (LIP)) in the cytoplasm. However, both transferrin receptor (TfR) and nuclear levels of HIF-1α were increased and these results point to a decrease in available iron. Such confounding results have been found in other systems and indicate that there is a much more complex regulation of intracellularly available iron (LIP) and its downstream effects on cell metabolism. Importantly, the Cp increased production and secretion of the neurotransmitter, glutamate, is a substantive finding of clinical relevance because of the neural and retinal degeneration found in aceruloplasminemia patients. This finding and Cp-induced nuclear translocation of the hypoxia-inducible factor-1 (HIF1) subunit HIF-1α adds novel information to the list of critical pathways impacted by Cp.

What do we (not) know about how paracetamol (acetaminophen) works?

WHAT IS KNOWN AND BACKGROUND

Although paracetamol (acetaminophen), N-(4-Hydroxyphenyl)acetamide, is one of the world's most widely used analgesics, the mechanism by which it produces its analgesic effect is largely unknown. This lack is relevant because: (i) optimal pain treatment matches the analgesic mechanism to the (patho)physiology of the pain and (ii) modern drug discovery relies on an appropriate screening assay.

OBJECTIVE

To review the clinical profile and preclinical studies of paracetamol as means of gaining insight into its mechanism of analgesic action.

METHODS

A literature search was conducted of clinical and preclinical literature and the information obtained was organized and reviewed from the perspective of its contribution to an understanding of the mechanism of analgesic action of paracetamol.

RESULTS

Paracetamol's broad spectrum of analgesic and other pharmacological actions is presented, along with its multiple postulated mechanism(s) of action. No one mechanism has been definitively shown to account for its analgesic activity.

WHAT IS NEW AND CONCLUSION

Further research is needed to uncover the mechanism of analgesic action of paracetamol. The lack of this knowledge affects optimal clinical use and impedes drug discovery efforts.

Cytochrome P450 CYP2C19 genotypes in Nigerian sickle-cell disease patients and normal controls

BACKGROUND AND OBJECTIVE

Subjects with different CYP2C19 genotypes may metabolize proguanil, a pro-drug used for malaria prophylaxis differently and the frequency of the different alleles may be different in patients with sickle-cell disease (SCD) and normal controls. The objective of this study was to evaluate CYP2C19 *1, *2 and *3 allele and genotype frequencies in Nigerian normal controls and SCD patients, and to further compare variant CYP2C19 frequencies in Nigerians with other African populations.

METHODS

Genotyping was carried out with PCR and restriction fragment length polymorphism analysis.

RESULTS AND DISCUSSION

CYP2C19 *1 (84·3 vs. 84·9%) or *2 allele frequency (15·7 vs. 15·1%) was not significantly different between patients with SCD and normal subjects. No *3 allele was detected in the cohort. The SCD group exhibited a statistically significantly lower frequency of *1/*1 genotype (69·6%) compared with normal controls (74·4%). Frequency of *2/*2 was significantly lower in SCD (0·9%) compared with normal controls (4·7%). Frequencies of *1/*2 (29·6 vs. 20·9%) were no different in SCD and normal controls.

CONCLUSION

Prevalence of CYP2C19 polymorphisms was defined for the first time in Nigerian normal and SCD populations. Nigerian SCD patients exhibited significantly lower CYP2C19 *1/*1 and *2/*2 frequencies than normal controls. No differences were detected in CYP2C19 allele or genotype frequencies in normal subjects between this study and previous reports in other African populations.

Avian influenza virus H9N2 survival at different temperatures and pHs

The H9N2 avian influenza virus (AIV) subtype has become endemic in Israel since its introduction in 2000. The disease has been economically damaging to the commercial poultry industry, in part because of the synergistic pathology of coinfection with other viral and/or bacterial pathogens. Avian influenza virus viability in the environment depends on the cumulative effects of chemical and physical factors, such as humidity, temperature, pH, salinity, and organic compounds, as well as differences in the virus itself. We sought to analyze the viability of AIV H9N2 strains at three temperatures (37, 20, and 4 C) and at 2 pHs (5.0 and 7.0). Our findings indicated that at 37 C AIV H9N2 isolate 1525 (subgroup IV) survived for a period of time 18 times shorter at 20 C, and 70 times shorter period at 4 C, as measured by a decrease in titer. In addition, the virus was sensitive to a lower pH (pH 5.0) with no detectable virus after 1 wk incubation at 20 C as compared to virus at pH 7.0, which was viable for at least 3 wk at that temperature. The temperature sensitivity of the virus corresponds to the occurrence of H9N2 outbreaks during the winter, and lower pH can greatly affect the viability of the virus.

Modeling of diarylalkyl-imidazole and diarylalkyl-triazole derivatives as potent aromatase inhibitors for treatment of hormone-dependent cancer

Aromatase is an enzyme that catalyzes the final step in the conversion of androgen to estrogen. It has become an attractive target for the treatment of estrogen responsive breast cancer. The study has been focused on designing aromatase inhibitors (AIs) that can be selected as probable drug candidate for the treatment of breast cancer. In the present study, long chain diarylalkyl-imidazole and -triazole scaffolds have been considered for exploring pharmacophores as potent AIs using QSAR (Quantitative SAR) and pharmacophore mapping studies. The model generated in linear free energy QSAR study (R(2) = 0.905, Q(2)= 0.885, R(2)(pred(ts)) = 0.763) showed the importance of hydrophobicity, size and shape of the molecule, van der Waals surface and hydrogen atom contribution influence the activity. 3D QSAR of comparative molecular field analysis (CoMFA, R(2)= 0.921, Q(2) = 0.741, R(2)(pred(ts))= 0.583) showed that steric and electrostatic features along with hydrophobicity and electronic charge contribution at C(4) (Fig. 1) influence on the inhibitory activity. Comparative molecular similarity analysis (CoMSIA, R(2) = 0.874, Q(2) = 0.716, R(2)(pred(ts)) = 0.591) study adjudged the presence of steric, electrostatic and hydrophobic fields together with hydrogen bond (HB) donor and acceptor play significant role in inhibitory activity to aromatase enzyme. Further pharmacophore mapping study (Q(2) = 0.947, Delta(cost) = 113.171, R(2)(pred(ts)) = 0.857) suggested that presence of HB acceptor, hydrophobicity with aromatic ring, and the importance of steric contribution influence on the activity. The critical distances among the features are also important for the inhibitor activity.

Metabolic interactions between prokinetic agents domperidone and erythromycin: an in vitro analysis

This study examined in vitro interaction between domperidone and erythromycin. Both are prescribed for refractory gastroparesis. Domperidone is metabolized via human cytochrome P4503A4. Erythromycin is a CYP3A4 inhibitor. Incubations evaluated domperidone metabolite formation in human liver microsomes and recombinant CYP3A4. Concentration- and time-dependent inhibition of 500 microM domperidone was studied with 2.5-200 microM erythromycin over 10-40 min. Domperidone metabolite (5-hydroxy domperidone, M3) formation was inhibited by erythromycin in a concentration- and time-dependent manner. The K(I) estimate was 18.4 microM in human liver microsomes and 4.1 microM in CYP3A4. Using a model incorporating CYP3A4 hepatic and gut inhibition, in vitro estimates from human liver microsomes and CYP3A4 were used to predict in vivo AUCi/AUC ratios of 2.54 and 4.95, respectively. Significant inhibition of domperidone metabolism by erythromycin occurs. This predicts greater domperidone drug exposure when used with erythromycin. This important drug-drug interaction will be evaluated in future human studies.

Distribution of ferritin chains in canine lenses with and without age-related nuclear cataracts

PURPOSE

It was determined in an earlier study that ferritin-heavy (H) and -light (L) chains in lens fiber cells are modified in comparison to those in lens epithelial cells. The purpose of the present study was to determine whether changes in ferritin chain characteristics are developmental, age-related, or associated with cataractogenesis, by analyzing the distribution of modified chains throughout the lens fiber mass.

METHODS

After removing the capsule, noncataractous and cataractous lenses were separated into six layers of fiber cells. The content of ferritin H and L chains in each layer was determined by western blotting with chain-specific antibodies. The level of ferritin complex (450 kDa protein made up of assembled L and H chains) was determined using the enzyme-linked immunosorbent assay. The ability of ferritin complex to bind iron was assessed by in vitro labeling with (59)Fe.

RESULTS

Fiber cell ferritin L chains were 30 kDa (modified from the normal 19 kDa), and were present at the highest level in the outermost layers of both cataractous and non-cataractous lenses. The amount of modified L chains decreased gradually in the inner layers of the fiber mass, and was undetectable in the inner two layers of cataractous lenses. The ferritin H chains were also modified to 12 kDa (perhaps truncated from the normal 21 kDa size) in both cataractous and non-cataractous lenses. Similar levels of this modified H chain were found throughout the normal lens. Interestingly, in cataractous lenses, the modified H chains were found in decreasing amounts towards the interior of the lens, and were undetectable in the nucleus. However, in these cataractous lenses, the normal-sized ferritin H chains (21 kDA) appear in small quantities in the outer fiber layers, and increase in quantity and size (to 29 kDa) in the inner layers. This observation was best seen and demonstrated in advanced cataracts. Ferritin, which can bind iron, was found mainly in the outer layers of the lens fiber mass of normal lenses, but was more evenly distributed in fiber layers from cataractous lenses.

CONCLUSIONS

Both ferritin H and L chains were modified in lens fiber cells from normal and cataractous canine lenses. These modifications were not age-related, and most likely occur during the differentiation of epithelial cells to fiber cells, since only normal-sized chains have been found in lens epithelial cells. In addition, there was a specific and distinct distribution of these modified chains throughout the lens fiber mass. The most striking differences between normal and cataractous lenses fiber cells were the appearance of normal-sized ferritin H chains and the relatively even distribution of iron binding capacity throughout the fiber mass of the cataractous lenses. These differences may reflect a response of the lens to increased oxidative stress during cataractogenesis.

The chemokine system and CCR5 antagonists: potential in HIV treatment and other novel therapies

Since the recognition of human acquired immune deficiency syndrome, numerous classes of pharmacologic therapeutics have been developed to manage the disease. Current therapy includes co-administration of combinations of drugs classified by their mechanism of action as 'transcriptase inhibitors', 'protease inhibitors', 'integrase inhibitors' and the more recent 'fusion inhibitors'. This review focuses on the chemokine system and the recognition of chemokine receptors as targets for anti-human immunodeficiency virus (HIV) therapy. The FDA-approved chemokine (C-C motif) receptor 5 (CCR5) antagonist maraviroc (Selzentry) is discussed in detail, along with another compound vicriviroc, currently in clinical trials. The mechanism of action, pharmacokinetics, toxicity and current status of research on CCR5 antagonists is described. Further, potential therapeutic uses of these agents other than anti-HIV therapy are discussed.

Iron metabolism in the eye: a review

This review article covers all aspects of iron metabolism, which include studies of iron levels within the eye and the processes used to maintain normal levels of iron in ocular tissues. In addition, the involvement of iron in ocular pathology is explored. In each section there is a short introduction to a specific metabolic process responsible for iron homeostasis, which for the most part has been studied in non-ocular tissues. This is followed by a summary of our current knowledge of the process in ocular tissues.

Lack of interaction between metoclopramide and morphine in vitro and in mice

1. This study examined interactions via common metabolism or via common pharmacodynamic pathways between frequently co-prescribed metoclopramide (a prokinetic) and morphine (an opioid analgesic). 2. In human liver microsomes, morphine 3-glucuronide and morphine 6-glucuronide formation had V(max) estimates of 6.2 +/- 0.07 and 0.75 +/- 0.01 (nmole min(-1) mg(-1) protein) and K(m) estimates of 1080 +/- 37 and 665 +/- 55 (microM), respectively. The in vitro K(i) for morphine 3-glucuronide formation in the presence of metoclopramide in human liver microsomes or recombinant uridine diphosphoglucuronosyltransferase 2B7 predicted a lack of in vivo interaction. 3. Morphine (2 mg kg(-1) subcutaneously) delayed gastrointestinal meal transit in mice, metoclopramide (10 mg kg(-1) subcutaneously) had no effect on meal transit, and metoclopramide did not alter this effect of morphine. 4. Morphine (2 or 5 mg kg(-1) subcutaneously) was antinociceptive in mice (hot plate test) and metoclopramide (10 mg kg(-1) subcutaneously) did not alter the antinociceptive effects of morphine. 5. Together, the data suggest a lack of interaction between morphine and metoclopramide.

Pharmacophore mapping of flavone derivatives for aromatase inhibition

Aromatase, which catalyses the final step in the steroidogenesis pathway of estrogen, has been target for the design of inhibitor in the treatment of hormone dependent breast cancer for postmenopausal women. The extensive SAR studies performed in the last 30 years to search for potent, selective and less toxic compounds, have led to the development of second and third generation of non-steroidal aromatase inhibitors (AI). Besides the development of synthetic compounds, several naturally occurring and synthetic flavonoids, which are ubiquitous natural phenolic compounds and mediate the host of biological activities, are found to demonstrate inhibitory effects on aromatase. The present study explores the pharmacophores, i.e., the structural requirements of flavones (Fig. 1) for inhibition of aromatase activity, using quantitative structure activity relationship (QSAR) and space modeling approaches. The classical QSAR studies generate the model (R (2) = 0.924, Q (2) = 0.895, s = 0.233) that shows the importance of aromatic rings A and C, along with substitutional requirements in meta and para positions of ring C for the activity. 3D QSAR of Comparative Molecular Field Analysis (CoMFA, R (2) = 0.996, R(2)(cv) = 0.791) and Comparative Molecular Similarity Analysis (CoMSIA, R (2) = 0.992, R(2)(cv) = 0.806) studies show contour maps of steric and hydrophobic properties and contribution of acceptor and donor of the molecule, suggesting the presence of steric hindrance due to ring C and R''-substituent, bulky hydrophobic substitution in ring A, along with acceptors at positions 11, and alpha and gamma of imidazole ring, and donor in ring C favor the inhibitory activity. Further space modeling (CATALYST) study (R = 0.941, Delta( cost ) = 96.96, rmsd = 0.876) adjudge the presence of hydrogen bond acceptor (keto functional group), hydrophobic (ring A) and aromatic rings (steric hindrance) along with critical distance among features are important for the inhibitory activity.

Pharmacophore mapping of arylbenzothiophene derivatives for MCF cell inhibition using classical and 3D space modeling approaches

Considering the worth of developing non-steroidal estrogen analogs, the present study explores the pharmacophore features of arylbenzothiophene derivatives for inhibitory activity to MCF-7 cells using classical QSAR and 3D space modeling approaches. The analysis shows that presence of phenolic hydroxyl group and ketonic linkage in the basic side chain of 2-arylbenzothiophene core of raloxifene derivatives are crucial. Additionally piperidine ring connected through ether linkage is favorable for inhibition of breast cancer cell line. These features for inhibitory activity are also highlighted through 3D space modeling approach that explored importance of critical inter features distance among HB-acceptor lipid, hydrophobic and HB-donor features in the arylbenzothiophene scaffold for activity.

The endocannabinoid system and rimonabant: a new drug with a novel mechanism of action involving cannabinoid CB1 receptor antagonism--or inverse agonism--as potential obesity treatment and other therapeutic use

There is considerable evidence that the endocannabinoid (endogenous cannabinoid) system plays a significant role in appetitive drive and associated behaviours. It is therefore reasonable to hypothesize that the attenuation of the activity of this system would have therapeutic benefit in treating disorders that might have a component of excess appetitive drive or over-activity of the endocannabinoid system, such as obesity, ethanol and other drug abuse, and a variety of central nervous system and other disorders. Towards this end, antagonists of cannabinoid receptors have been designed through rational drug discovery efforts. Devoid of the abuse concerns that confound and impede the use of cannabinoid receptor agonists for legitimate medical purposes, investigation of the use of cannabinoid receptor antagonists as possible pharmacotherapeutic agents is currently being actively investigated. The compound furthest along this pathway is rimonabant, a selective CB(1) (cannabinoid receptor subtype 1) antagonist, or inverse agonist, approved in the European Union and under regulatory review in the United States for the treatment of obesity. This article summarizes the basic science of the endocannabinoid system and the therapeutic potential of cannabinoid receptor antagonists, with emphasis on the treatment of obesity.

Pharmacophore Mapping of Selective Binding Affinity of Estrogen Modulators through Classical and Space Modeling Approaches: Exploration of Bridged-Cyclic Compounds with Diarylethylene Linkage

Research on Selective Estrogen Receptor Modulators (SERMs) has been driven by interest in discovering target selective molecules. In view of such significance, the present work explored the pharmacophores of estrogen receptor (ER) subtypes specific binding affinities of diverse compounds belonging to the category of bridged bicyclic-1,1-diarylethylene derivatives. Implementing classical QSAR and CATALYST based space-modeling approaches, it has been explored that attachment of aryl ring systems to unsaturated linkages, availability of phenolic hydroxyl group, global hydrophobicity, and stereochemistry of certain functional groups might be important for governing the subtype specific estrogenic behavior of this group of compounds. Supplementing this deduction, critical interfeature distances between hydrogen bond acceptor, hydrophobic, and ring aromatic features along with steric influence are found to primarily influence the ER-subtypes specific binding of this series of compounds.

Uridine diphosphoglucuronosyltransferase pharmacogenetics and cancer

The uridine diphosphoglucuronosyltransferases (UGTs) belong to a superfamily of enzymes that catalyse the glucuronidation of numerous endobiotics and xenobiotics. Several human hepatic and extrahepatic UGT isozymes have been characterized with respect to their substrate specificity, tissue expression and gene structure. Genetic polymorphisms have been identified for almost all the UGT family members. A wide variety of anticancer drugs, dietary chemopreventives and carcinogens are known to be conjugated by members of both UGT1A and UGT2B subfamilies. This review examines in detail each UGT isozyme known to be associated with cancer and carcinogenesis. The cancer-related substrates for several UGTs are summarized, and the functionally relevant genetic polymorphisms of UGTs are reviewed. A number of genotype-phenotype association studies have been carried out to characterize the role of UGT pharmacogenetics in several types of cancer, and these examples are discussed here. In summary, this review focuses on the role of the human UGT genetic polymorphisms in carcinogenesis, chemoprevention and cancer risk.

Is there any correlation between severity of epilepsy and cognitive abilities in patients with temporal lobe epilepsy?

Frequent refractory seizures may cause cognitive deterioration when they present at an early age, especially in infants. The findings of previous studies designed to examine the impact of repetitive seizures on cognition in adolescents and adults, however, have shown wide variation. We analyzed the data of neuropsychological evaluations of patients before they underwent temporal lobe resection because of refractory seizure disorder in our institution from 1998 to 2001. Forty-four consecutive patients aged 12-48 years underwent a comprehensive neuropsychological evaluation that included a battery of selected visual and verbal memory tests. Statistical analysis revealed no significant correlation between disease-related parameters, such as age of onset, duration of active disease, estimated cumulative number of complex partial seizures and secondarily generalized seizures, and the results of neuropsychological tests. These findings support the hypothesis that factors other than repetitive seizures are responsible for cognitive dysfunction among adolescents and adults.

A meta-analysis of salvage therapy for Pneumocystis carinii pneumonia

OBJECTIVE

To determine the relative efficacies of alternative antipneumocystis agents in human immunodeficiency virus (HIV)-infected patients with Pneumocystis carinii pneumonia unresponsive to primary drug treatment with a combination product of trimethoprim and sulfamethoxazole or parenteral pentamidine.

METHODS

Meta-analysis of 27 published clinical drug trials, case series, and case reports involving P carinii pneumonia. Data extracted included underlying disease, primary antipneumocystis treatment, days of failed primary treatment, salvage regimen, use of systemic corticosteroids and antiretroviral drugs, and clinical outcome.

RESULTS

In 497 patients with microbiologically confirmed P carinii pneumonia (456 with HIV or acquired immunodeficiency syndrome), initial antipneumocystis treatment failed and they therefore required alternative drug therapy. Failed regimens included trimethoprim-sulfamethoxazole (160 patients), intravenous pentamidine (63 patients), trimethoprim-sulfamethoxazole and/or pentamidine (258 patients), aerosolized pentamidine (6 patients), atovaquone (3 patients), dapsone (3 patients), a combination product of trimethoprim and dapsone (2 patients), and trimethoprim-sulfamethoxazole followed by a combination of clindamycin and primaquine phosphate (2 patients). Efficacies of salvage regimens were as follows: clindamycin-primaquine (42 to 44 [88%-92%] of 48 patients; P<10(-8)), atovaquone (4 [80%] of 5), eflornithine hydrochloride (40 [57%] of 70; P<.01), trimethoprim-sulfamethoxazole (27 [53%] of 51; P<.08), pentamidine (64 [39%] of 164), and trimetrexate (47 [30%] of 159).

CONCLUSION

The combination of clindamycin plus primaquine appears to be the most effective alternative treatment for patients with P carinii pneumonia who are unresponsive to conventional antipneumocystis agents.

Mutations in the alpha-synuclein gene in Parkinson's disease among Indians

OBJECTIVE

To investigate the prevalence of G88C, G209A and any other mutation(s) in exons 3 and 4 of the alpha-synuclein gene in Indian patients with Parkinson's disease (PD).

METHODS

A total of 169 PD patients comprising 18 familial, 3 juvenile, 48 early onset and 100 sporadic cases were included in this study. Genomic DNA was amplified by PCR using primers specific for Exons 3 and 4. Mutations at G88C and G209A were screened following restriction enzyme digestion of the PCR product. Direct PCR product sequencing of entire exons 3 and 4 was carried out for at least one proband each from the 10 familial cases.

RESULTS

Neither G88C and G209A mutations nor any other mutation in exons 3 and 4 was found in the PD patients analysed.

CONCLUSION

The G88C and G209A mutations do not seem to be the predominant genetic determinant of PD among Indians.

A geminivirus replication protein interacts with the retinoblastoma protein through a novel domain to determine symptoms and tissue specificity of infection in plants

Geminiviruses replicate in nuclei of mature plant cells after inducing the accumulation of host DNA replication machinery. Earlier studies showed that the viral replication factor, AL1, is sufficient for host induction and interacts with the cell cycle regulator, retinoblastoma (pRb). Unlike other DNA virus proteins, AL1 does not contain the pRb binding consensus, LXCXE, and interacts with plant pRb homo logues (pRBR) through a novel amino acid sequence. We mapped the pRBR binding domain of AL1 between amino acids 101 and 180 and identified two mutants that are differentially impacted for AL1-pRBR interactions. Plants infected with the E-N140 mutant, which is wild-type for pRBR binding, developed wild-type symptoms and accumulated viral DNA and AL1 protein in epidermal, mesophyll and vascular cells of mature leaves. Plants inoculated with the KEE146 mutant, which retains 16% pRBR binding activity, only developed chlorosis along the veins, and viral DNA, AL1 protein and the host DNA synthesis factor, proliferating cell nuclear antigen, were localized to vascular tissue. These results established the importance of AL1-pRBR interactions during geminivirus infection of plants.