Elucidating the role of N440K mutation in SARS-CoV-2 spike - ACE-2 binding affinity and COVID-19 severity by virtual screening, molecular docking and dynamics approach.

COVID-19 has become a public health concern around the world. The frequency of N440K variant was higher during the second wave in South India. The mutation was observed in the Receptor Binding Domain region (RBD) of the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) spike (S) protein. The binding affinity of SARS-CoV-2-Angiotensin-Converting Enzyme-2 (ACE-2) plays a major role in the transmission and severity of the disease. To understand the binding affinity of the wild and mutant SARS-CoV-2 S with ACE2, molecular modeling studies were carried out. We discovered that the wild SARS-CoV-2 S RBD-ACE-2 complex has a high binding affinity and stability than that of the mutant. The N440K strain escapes from antibody neutralization, which might increase reinfection and decrease vaccine efficiency. To find a potential inhibitor against mutant N440K SARS-CoV-2, a virtual screening process was carried out and found ZINC169293961, ZINC409421825 and ZINC22060839 as the best binding energy compounds. Communicated by Ramaswamy H. Sarma.

Comparison of mammosphere formation from stem-like cells of normal breast, malignant primary breast tumors, and MCF-7 cell line.

BACKGROUND: Mammosphere formation assay has become a versatile tool to quantify the activity of putative breast cancer stem cells in non-adherent in vitro cultures. However, optimizing the suspension culture system is crucial to establish mammosphere cultures from primary breast tumors. METHODS: This study aimed at determining the self-renewal and sphere-forming potential of breast cancer stem-like cells derived from human primary invasive ductal carcinoma and normal breast tissue samples, and MCF-7 breast cancer cell line using an optimal suspension culture system. Mammosphere-forming efficiency of the mammospheres generated from the tissue samples and cell line were compared. We evaluated the expression of CD44+/CD24-/low and CD49f+/EpCAM-/low phenotypes in the stem-like cells by flow cytometry. CK-18, CK-19, α-SMA, and EpCAM marker expression was assessed using immunohistochemical staining. RESULTS: Breast epithelial cells isolated from the three samples formed two-dimensional spheroids in suspension cultures. Interestingly, mammospheres formed from patient-derived primary breast tumors were enriched in breast cancer stem-like cells with the phenotype CD44+/CD24-/low and exhibited a relatively more number of large spheres when compared to the normal breast stem cells. MCF-7-derived SCs were more aggressive and resulted in the formation of a significantly higher number of spheroids. The expression of CK-18/CK-19 and α-SMA/EpCAM proteins was confirmed in breast cancer tissues. CONCLUSIONS: Thus, the use of primary tumor specimens and breast cancer cell lines as suitable models for elucidating the breast cancer stem cell activity was validated using mammosphere culture system.

Repurposing of potential antiviral drugs against RNA-dependent RNA polymerase of SARS-CoV-2 by computational approach.

The high incidences of COVID-19 cases are believed to be associated with high transmissibility rates, which emphasizes the need for the discovery of evidence-based antiviral therapies for curing the disease. The rationale of repurposing existing classes of antiviral small molecule therapeutics against SARS-CoV-2 infection has been expected to accelerate the tedious and expensive drug development process. While Remdesivir has been recently approved to be the first treatment option for specific groups of COVID-19 patients, combinatory therapy with potential antiviral drugs may be necessary to enhance the efficacy in different populations. Hence, a comprehensive list of investigational antimicrobial drug compounds such as Favipiravir, Fidaxomicin, Galidesivir, GC376, Ribavirin, Rifabutin, and Umifenovir were computationally evaluated in this study. We performed in silico docking and molecular dynamics simulation on the selected small molecules against RNA-dependent RNA polymerase, which is one of the key target proteins of SARS-CoV-2, using AutoDock and GROMACS. Interestingly, our results revealed that the macrocyclic antibiotic, Fidaxomicin, possesses the highest binding affinity with the lowest energy value of -8.97 kcal/mol binding to the same active sites of RdRp. GC376, Rifabutin, Umifenovir and Remdesivir were identified as the next best compounds. Therefore, the above-mentioned compounds could be considered good leads for further preclinical and clinical experimentations as potentially efficient antiviral inhibitors for combination therapies against SARS-CoV-2.

Ellagic Acid as a Potential Inhibitor against the Nonstructural Protein NS3 Helicase of Zika Virus: A Molecular Modelling Study.

Zika virus is a member of the Flaviviridae family and genus Flavivirus, which has a phylogenetic relationship with spondweni virus. It spreads to humans through a mosquito bite. To identify potential inhibitors for the Zika virus with biosafety, we selected natural antiviral compounds isolated from plant sources and screened against NS3 helicase of the Zika virus. The enzymatic activity of the NS3 helicase is associated with the C-terminal region and is concerned with RNA synthesis and genome replication. It serves as a crucial target for the Zika virus. We carried out molecular docking for the target NS3 helicase against the selected 25 phytochemicals using AutoDock Vina software. Among the 25 plant compounds, we identified NS3 helicase-ellagic acid (-9.9 kcal/mol), NS3 helicase-hypericin (-9.8 kcal/mol), and NS3 helicase-pentagalloylglucose (-9.5 kcal/mol) as the best binding affinity compounds based on their binding energies. To understand the stability of these complexes, molecular dynamic simulations were executed and the trajectory analysis exposed that the NS3 helicase-ellagic acid complex possesses greater stability than the other two complexes such as NS3 helicase-hypericin and NS3 helicase-pentagalloylglucose. The ADMET property prediction of these compounds resulted in nontoxicity and noncarcinogenicity.

A Computational approach to screen, predict and annotate human and chimpanzee PHEX intronic miRNAs, their gene targets, and regulatory interaction networks.

The knowledge of what separates us genetically from our less-evolved relatives is crucial for gaining new biomedical insight about the human-chimpanzee relatedness that could influence the development of new treatments and diagnostic aids for various ailments. Especially, more than 300 diseases have been mapped to the X chromosome, which has unique and complicated characteristics than other chromosomes in the human genome. Although the genomes of humans and chimpanzees share 99% similarity, significant differences exist between the two species in their non-coding intronic regions. Therefore, this evolutionary-based genome annotation study attempted to computationally compare, contrast, and annotate the homologous miRNAs and their gene regulatory mechanisms in the intronic regions of the PHEX gene on the human X chromosome of the two species. From our results, we identified a total of 1296 human miRNAs and 46, 957 gene targets. Similarly, 30, 563 targets of homologous chimp miRNAs were predicted. miRNAs like hsa-miR-17-5p showed a maximum number of interactions while miRNAs like hsa-miR-107 with the least number of interactions in the human/chimp gene networks. A few top-ranked miRNAs such as hsa-miR-24, hsa-miR-145, hsa-miR-34a, and hsa-miR-378 were observed to be common between the two genera. The cooperativity and multiplicity of certain miRNAs were predicted to regulate the expression of diverse cancer-associated genes such as Cyclin D1, Notch1, CDK-6, E2F3, ALK4, CKDN2A, DHFR, and MAPK14. Nevertheless, further in vitro and in vivo experimental validations of these gene candidates are required before they could be used as potential diagnostic markers and drug targets.

Plant-Derived Antiviral Compounds as Potential Entry Inhibitors against Spike Protein of SARS-CoV-2 Wild-Type and Delta Variant: An Integrative in SilicoApproach.

The wild-type SARS-CoV-2 has continuously evolved into several variants with increased transmissibility and virulence. The Delta variant which was initially identified in India created a devastating impact throughout the country during the second wave. While the efficacy of the existing vaccines against the latest SARS-CoV-2 variants remains unclear, extensive research is being carried out to develop potential antiviral drugs through approaches like in silico screening and drug-repurposing. This study aimed to conduct the docking-based virtual screening of 50 potential phytochemical compounds against a Spike glycoprotein of the wild-type and the Delta SARS-CoV-2 variant. Subsequently, molecular docking was performed for the five best compounds, such as Lupeol, Betulin, Hypericin, Corilagin, and Geraniin, along with synthetic controls. From the results obtained, it was evident that Lupeol exhibited a remarkable binding affinity towards the wild-type Spike protein (-8.54 kcal/mol), while Betulin showed significant binding interactions with the mutated Spike protein (-8.83 kcal/mol), respectively. The binding energy values of the selected plant compounds were slightly higher than that of the controls. Key hydrogen bonding and hydrophobic interactions of the resulting complexes were visualized, which explained their greater binding affinity against the target proteins-the Delta S protein of SARS-CoV-2, in particular. The lower RMSD, the RMSF values of the complexes and the ligands, Rg, H-bonds, and the binding free energies of the complexes together revealed the stability of the complexes and significant binding affinities of the ligands towards the target proteins. Our study suggests that Lupeol and Betulin could be considered as potential ligands for SARS-CoV-2 spike antagonists. Further experimental validations might provide new insights for the possible antiviral therapeutic interventions of the identified lead compounds and their analogs against COVID-19 infection.

Machine learning modeling to identify affinity improved biobetter anticancer drug trastuzumab and the insight of molecular recognition of trastuzumab towards its antigen HER2.

In the present study, a machine learning (ML) model was developed to predict the epistatic phenomena of combination mutants to improve the anticancer antibody-drug trastuzumab's binding affinity towards its antigen human epidermal growth factor receptor 2 (HER2). An ML algorithm, Support Vector Regression (SVR) was used to develop ML models with a data set consists of 193 affinity values of single mutants of trastuzumab and its associated various amino acid sequence derived descriptors. The subset selection of descriptors and SVR hyperparameters were done using the Genetic Algorithm (GA) within the SVR and the wrapper approach called GA-SVR. A 100 evolutionary cycles of GA produced the best 100 probable GA-SVR models based on their fitness score (Q2) estimated using a stratified 5 fold cross-validation procedure. The final ML model found to be highly predictive of test data set of six combination mutants and one single mutant with Rpre2 = 0.71. The analysis of descriptors in the ML model highlighted the importance of mutant induced secondary structural variation causes the binding affinity variation of the trastuzumab. The same was verified using a short 20 ns and a long 100 ns in duplicate molecular dynamics simulation of a wild and mutant variant of trastuzumab. The secondary structure induced affinity change due to mutations in the CDR-H3 is a novel insight that came out of this study. That should help rational mutant selection to develop a biobetter trastuzumab with a multifold improved binding affinity into the market quickly.Communicated by Ramaswamy H. Sarma.

Structure-Based Virtual Screening of Benzaldehyde Thiosemicarbazone Derivatives against DNA Gyrase B of Mycobacterium tuberculosis.

Emergence of antibiotic-resistant Mycobacterium tuberculosis (M. tuberculosis) restricts the availability of drugs for the treatment of tuberculosis, which leads to the increased morbidity and mortality of the disease worldwide. There are many intrinsic and extrinsic factors that have been reported for the resistance mechanism. To overcome such mechanisms, chemically synthesized benzaldehyde thiosemicarbazone derivatives were screened against M. tuberculosis to find potential inhibitor for tuberculosis. Such filtering process resulted in compound 13, compound 21, and compound 20 as the best binding energy compounds against DNA gyrase B, an important protein in the replication process. The ADMET prediction has shown the oral bioavailability of the novel compounds.

Molecular docking data of E3 ubiquitin-protein ligase WWP1 with compounds from a medicinal plant Justicia adhatoda L.

It is known that E3 ubiquitin-protein ligase WWP1 is linked to oral cancer. Therefore, it is of interest to document molecular docking data of E3 ubiquitin-protein ligase WWP1 with compounds ((Stigmasterol, Pyrazinamide, Vasicinone and Ethambutol)) from a medicinal plant Justicia adhatoda L for further consideration.

Molecular docking analysis of SARS-CoV-2 linked RNA dependent RNA polymerase (RdRp) with compounds from Plectranthus amboinicus.

It is of interest to document the moelcular docking analysis of SARS-CoV-2 linked RNA dependent RNA polymerase (RdRp) with compounds from Plectranthus amboinicus. Hence, we report the binding features of rutin, Luteolin, Salvianolic acid A, Rosmarinic acid and p-Coumaric acid with the target protein SARS-CoV-2 linked RNA dependent RNA polymerase (RdRp) for further consideration.

Molecular modeling of cornulin (CRNN) for docking with phytocompounds from Justicia adhatoda L.

Cornulin (CRNN) is linked with tumour progression. Therefore, it is of interest to document data on the molecular modeling of cornulin (CRNN) for docking with phytocompounds (Pyrazinamide, Anisotine, Vasicinone, Vasicoline) from Justicia adhatoda L. Thus, we document the optimal binding features of these compounds with the cornulin model for further consideration.

Molecular docking of alkaloid compounds with the matrix metalloproteinase 2.

Matrix metalloproteinase protein-2 (MMP-2) is linked to the human oral squamous cell carcinoma. Therefore, it is of interest to design new inhibitors for MMP-2 to combat the disease. Thus, we document the molecular docking features of Aristolochic acid, Cryptopleurine, Epipodophyllotoxin, and Fagaronine with MMP-2 for further consideration.

Molecular docking of potential inhibitors with the mTOR protein.

The mTOR (mammalian or mechanistic Target of Rapamycin) is linked with oral cancer. Therefore, it is of interest to study the molecular docking-based binding of paclitaxel (a FDA approved drug for oral cancer) and its analogues with mTOR. Hence, we report the binding features of 10-Deacetyltaxol, 7-Epi-10-deacetyltaxol, 7-Epi-Taxol and 6alpha-Hydroxypaclitaxel with mTOR for further consideration.

Comparison of Immunological Profiles of SARS-CoV-2 Variants in the COVID-19 Pandemic Trends: An Immunoinformatics Approach.

The current dynamics of the COVID-19 pandemic have become a serious concern with the emergence of a series of mutant variants of the SARS-CoV-2 virus. Unlike the previous strain, it is reported that the descendants are associated with increased risk of transmission yet causing less impact in terms of hospital admission, the severity of illness, or mortality. Moreover, the vaccine efficacy is also not believed to vary among the population depending on the variants of the virus and ethnicity. It has been determined that the mutations recorded in the spike gene and protein of the newly evolved viruses are specificallyresponsible for this transformation in the behavior of the virus and its disease condition. Hence, this study aimed to compare the immunogenic profiles of the spike protein from the latest variants of the SARS-CoV-2 virus concerning the probability of COVID-19 severity. Genome sequences of the latest SARS-CoV-2 variants were obtained from GISAID and NCBI repositories. The translated protein sequences were run against T-cell and B-cell epitope prediction tools. Subsequently, antigenicity, immunogenicity, allergenicity, toxicity, and conservancy of the identified epitopes were ascertained using various prediction servers. Only the non-allergic and non-toxic potential epitopes were matched for population relevance by using the Human Leucocyte Antigen population registry in IEDB. Finally, the selected epitopes were validated by docking and simulation studies. The evaluated immunological parameters would concurrently reveal the severity of COVID-19, determining the infection rate of the pathogen. Our immunoinformatics approach disclosed that spike protein of the five variants was capable of forming potential T and B-cell epitopes with varying immune responses. Although the Wuhan strain showed a high number of epitope/HLA combinations, relatively less antigenicity and higher immunogenicity results in poor neutralizing capacity, which could be associated with increased disease severity. Our data demonstrate that increased viral antigenicity with moderate to high immunogenicity, and several potential epitope/HLA combinations in England strain, the USA, India, and South Africa variants, could possess a high neutralizing ability. Therefore, our findings reinforce that the newly circulating variants of SARS-CoV-2 might be associated with more infectiousness and less severe disease condition despite their greater viremia, as reported in the recent COVID-19 cases, whichconsequently determine their increased epidemiological fitness.

Understanding the binding conformation of ceftolozane/tazobactam with Metallo-ß-lactamases VIM-5 and IMP-7 of Pseudomonas aeruginosa: A molecular docking and virtual screening process.

Pseudomonas aeruginosa (P. aeruginosa) is one of the community-acquired and healthcare-associated infections causing organisms. It has become resistant to most of the available antibiotics and is termed multi-drug resistance (MDR). There are a limited number of antibiotics are available to treat such MDR organism causing infections. The ceftolozane/tazobactam is one among the combination drug therapy (CDT) prescribed for the treatment of MDR causing infections. The resistance for the same CDT was observed in the MDR P. aeruginosa harboring VIM-5 and IMP-7 Metallo beta (ß)-lactamases (MBLs). To explore the resistance mechanism at the molecular level, docking studies were carried out for antibiotics against VIM-5 and IMP-7 MBLs. The Zn2 metal ions carry out the nucleophile attack on the carbonyl carbon of the ß-lactam ring along with conserved water molecules. To find lead compounds against the MBLs, a virtual screening process was carried out. We have employed MODELLER for structure modeling, AutoDock for molecular docking and AutoDock Vina, Molinspiration, PASS prediction & admetSAR in virtual screening. The search of low binding energy ceftolozane analogs against VIM-5 and IMP-7 MBLs has resulted in the ZINC000029060075 and ZINC000009163636 analogs. Similarly, the screening of high binding energy inhibitors against VIM-5 and IMP-7 MBLs has resulted in ZINC000003831503 and ZINC000000897247 tazobactam analogs respectively. The ADMET prediction results in the non-toxicity of the lead compounds. Our study may provide new insights for the scientist who are designing novel drugs against MDR P. aeruginosa causing infections.

Knowledge on cervical cancer and perceived barriers to the uptake of HPV vaccination among health professionals.

BACKGROUND: Despite the fact that cervical cancer is preventable and curable in the early stages, it still remains to be a major public health problem in India. This study was conducted to assess the knowledge and awareness regarding the Human Papilloma Virus (HPV) vaccination among health care professionals working in a tertiary care hospital in urban India. METHODS: To this aim, we conducted a cross-sectional study among 318 health care professionals working in tertiary hospitals across Chennai, Tamil Nadu, India. Our research group designed a structured questionnaire with 31 items to assess the knowledge and attitudes on cervical cancer, its prevention, and HPV vaccination. RESULTS: Among the 318 respondents, 90.6% were aware of cervical cancer, 83.3% were aware that PAP (Papanicolaou) smear test detects cervical cancer, and 86.2% of the respondents knew that HPV causes cervical cancer. 29.2% of the eligible respondents underwent the screening against cervical cancer, and 19.8% of the study participants were vaccinated for HPV. Only 34.9% know that the HPV vaccine could be given to boys. The most common reason for not being vaccinated against HPV was the lack of awareness. In our study, 77.2% of the respondents were willing to be vaccinated and recommend HPV vaccination to their family members. CONCLUSION: From this study, it was evident that there is a lack of awareness about HPV vaccination and its importance in preventing cervical cancer among healthcare professionals. Our finding clearly establishes the need to devise intervention programs to promote vaccination against HPV and periodical screening for cervical cancer among healthcare professionals.