A high-throughput screening system for SARS-CoV-2 entry inhibition, syncytia formation and cell toxicity.

Background: The entry of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) into the host cell is mediated through the binding of the SARS-CoV-2 Spike protein via the receptor binding domain (RBD) to human angiotensin-converting enzyme 2 (hACE2). Identifying compounds that inhibit Spike-ACE2 binding would be a promising and safe antiviral approach against COVID-19.

Methods: In this study, we used a BSL-2 compatible replication-competent vesicular stomatitis virus (VSV) expressing Spike protein of SARS-CoV-2 with eGFP reporter system (VSV-eGFP-SARS-CoV-2) in a recombinant permissive cell system for high-throughput screening of viral entry blockers.

A rapid bead-based assay for screening of SARS-CoV-2 neutralizing antibodies.

Quantitative determination of neutralizing antibodies against Severe Acute Respiratory Syndrome Corona Virus-2 (SARS-CoV-2) is paramount in immunodiagnostics, vaccine efficacy testing, and immune response profiling among the vaccinated population. Cost-effective, rapid, easy-to-perform assays are essential to support the vaccine development process and immunosurveillance studies. We describe a bead-based screening assay for S1-neutralization using recombinant fluorescent proteins of hACE2 and SARS-CoV2-S1, immobilized on solid beads employing nanobodies/metal-affinity tags.

ER alpha selective chromone, isoxazolylchromones, induces ROS-mediated cell death without autophagy.

Chromones are recognized as privileged structures and useful templates for the design of novel compounds with promising pharmacological activity. Several reports implicate chromone scaffold as an antitumor agent. The present study highlights synthesis, docking, and potential activity of isoxazolylchromones, 3(a-f), a new class of compounds as potential agents exhibiting ERα antagonism and ERβ agonism.

Nonsteroidal estrogen receptor isoform-selective biphenyls.

Estrogen receptor (ER) has been a therapeutic target to treat ER-positive breast cancer, most notably by agents known as selective estrogen receptor modulators (SERMs). However, resistance and severe adverse effects of known drugs gave impetus to the search for newer agents with better therapeutic profile. ERα and ERβ are two isoforms sharing 56% identity and having different physiological functions and expressions in various tissues.

A quantitative real-time approach for discriminating apoptosis and necrosis.

Apoptosis and necrosis are the two major forms of cell death mechanisms. Both forms of cell death are involved in several physiological and pathological conditions and also in the elimination of cancer cells following successful chemotherapy. Large number of cellular and biochemical assays have evolved to determine apoptosis or necrosis for qualitative and quantitative purposes.

Pyrenacantha volubilis Wight, (Icacinaceae) a rich source of camptothecine and its derivatives, from the Coromandel Coast forests of India.

Camptothecine, a potent eukaryotic topoisomerase inhibitor, is an important anticancer compound. The global demand for this compound was estimated to be $1 billion in 2003 and is only further expected to increase. Partly to meet the expected increase in demand, in the recent past, several efforts have been made to discover newer and alternative plant and fungal sources of camptothecine.

Tricin 4'-O-(erythro-β-guaiacylglyceryl) ether and tricin 4'-O-(threo-β-guaiacylglyceryl) ether isolated from Njavara (Oryza sativa L. var. Njavara), induce apoptosis in multiple tumor cells by mitochondrial pathway.

Njavara is an important medicinal rice variety of Kerala, India widely used in Ayurveda for the treatment of rheumatoid arthritis, paralysis, neurodegenerative diseases and in rejuvenation therapy. The study evaluated, for the first time, antitumor effects of the two rare flavonolignans, tricin 4'-O-(erythro-β-guaiacylglyceryl) ether (compound 1) and tricin 4'-O-(threo-β-guaiacylglyceryl) ether (compound 2), isolated from 'Njavara' black. Both the compounds induced apoptosis in three cancer cell lines colon adenocarcinoma cell line HCT 116, ovarian cancer cell line SKOV3 and breast cancer cell line MCF-7.

Fusarium proliferatum, an endophytic fungus from Dysoxylum binectariferum Hook.f, produces rohitukine, a chromane alkaloid possessing anti-cancer activity.

Rohitukine is a chromane alkaloid possessing anti-inflammatory, anti-cancer and immuno-modulatory properties. The compound was first reported from Amoora rohituka (Meliaceae) and later from Dysoxylum binectariferum (Meliaceae) and Schumanniophyton problematicum (Rubiaceae). Flavopiridol, a semi-synthetic derivative of rohitukine is a potent CDK inhibitor and is currently in Phase III clinical trials.

High throughput ratio imaging to profile caspase activity: potential application in multiparameter high content apoptosis analysis and drug screening.

Recent advancement in the area of green fluorescent protein techniques coupled with microscopic imaging has significantly contributed in defining and dissecting subcellular changes of apoptosis with high spatio-temporal resolution. Although single cell based studies using EGFP and associated techniques have provided valuable information of initiation and hierarchical changes of apoptosis, they are yet to be exploited for multiparameter cell based real time analysis for possible drug screening or pathway defining in a high throughput manner. Here we have developed multiple cancer cell lines expressing FRET sensors for active caspases and adapted them for high throughput live cell ratio imaging, enabling high content image based multiparameter analysis.

Dysoxylum binectariferum Hook.f (Meliaceae), a rich source of rohitukine.

Rohitukine, a chromane alkaloid, is a precursor of flavopiridol, a promising anti-cancer compound. Currently in Phase III clinical trials, flavopiridol is a potent inhibitor of several cyclin-dependent kinases (CDKs). Rohitukine was first reported from Amoora rohituka (0.