Pharmacological profile of novel anti-cancer drugs approved by USFDA in 2022: A Review.

BACKGROUND: For any drug molecule, it is mandatory to pass the drug approval process of the concerned regulatory authority, before being marketed. The Food and Drug Administration (FDA), throughout the year, approves several new drugs for safety and efficacy. In addition to new drug approvals, FDA also works on improving access to generic drugs, aimed to lower the cost of drugs for patients and improve access to treatments. In the year 2022 twelve new drug therapies were approved for managing varying cancers. METHOD: This manuscript is focused to describe the pharmacological aspects including therapeutic uses, mechanisms of actions, pharmacokinetics, adverse effects, doses, indication for special cases, contraindications, etc., of novel FDA-approved anticancer drug therapies in the year 2022. RESULT: FDA has approved about 29% (11 out of 37) novel drug therapies for varying types of cancers such as lung cancer, breast cancer, prostate cancer, melanoma, leukemia, etc. The Center for Drug Evaluation and Research CDER has reported that 90% of these anticancer drugs (e.g. Adagrasib, Futibatinib, Mirvetuximabsoravtansine-gynx, Mosunetuzumab-axb, Nivolumab and relatlimab-rmbw, Olutasidenib, Pacritinib, Tebentafusp-tebn, Teclistamab-cqyv, and Tremelimumab-actl) as orphan drugs and recommended to treat rare or uncommon cancers such as non-small cell lung cancer, metastatic intrahepatic cholangio-carcinoma, epithelial ovarian cancer, follicular lymphoma, metastatic melanoma, metastatic uveal melanoma, etc. CDER has identified six anticancer drugs (e.g. Lutetium (177Lu)vipivotidetetraxetan, Mirvetuximabsoravtansine-gynx, Mosunetuzumab-axb, Nivolumab and relatlimab-rmbw, Tebentafusp-tebn, Teclistamab-cqyv) as first-in-class drugs i.e. drugs having different mechanisms of action from the already existing ones. The newly approved anticancer drugs shall provide more efficient treatment options for cancer patients. Three FDA-approved anticancer drugs in the year 2023 are also briefly described in the manuscript. CONCLUSION: This manuscript, describing the pharmacological aspects of eleven anticancer novel drug therapies approved by the FDA, shall serve as a helpful document for cancer patients, concerned academicians, researchers, and clinicians, especially oncologists.

Mechanistic insights into global suppressors of protein folding defects.

Most amino acid substitutions in a protein either lead to partial loss-of-function or are near neutral. Several studies have shown the existence of second-site mutations that can rescue defects caused by diverse loss-of-function mutations. Such global suppressor mutations are key drivers of protein evolution. However, the mechanisms responsible for such suppression remain poorly understood. To address this, we characterized multiple suppressor mutations both in isolation and in combination with inactive mutants. We examined six global suppressors of the bacterial toxin CcdB, the known M182T global suppressor of TEM-1 ß-lactamase, the N239Y global suppressor of p53-DBD and three suppressors of the SARS-CoV-2 spike Receptor Binding Domain. When coupled to inactive mutants, they promote increased in-vivo solubilities as well as regain-of-function phenotypes. In the case of CcdB, where novel suppressors were isolated, we determined the crystal structures of three such suppressors to obtain insight into the specific molecular interactions responsible for the observed effects. While most individual suppressors result in small stability enhancements relative to wildtype, which can be combined to yield significant stability increments, thermodynamic stabilisation is neither necessary nor sufficient for suppressor action. Instead, in diverse systems, we observe that individual global suppressors greatly enhance the foldability of buried site mutants, primarily through increase in refolding rate parameters measured in vitro. In the crowded intracellular environment, mutations that slow down folding likely facilitate off-pathway aggregation. We suggest that suppressor mutations that accelerate refolding can counteract this, enhancing the yield of properly folded, functional protein in vivo.

A Systematic Review of updated mechanistic insights towards Alzheimer's disease.

BACKGROUND AND PURPOSE: Alzheimer's disease (AD) is a degenerative neurological disorder that impairs memory, cognitive abilities, and the ability to do even most everyday activities. This neurodegenerative disease is growing increasingly common as the world's population ages. Here we reviewed some of the key findings that have shown the function of Aß peptide, oxidative stress, free radical damage Triggering Receptors Expressed on Myeloid Cells 2 (TREM2), Nitric Oxide (NO), and gut microbiota in the aetiology of AD. METHODOLOGY: The potentially relevant online medical databases, namely, PubMed, Scopus, Google Scholar, Cochrane Library, and JSTOR were exhaustively researched. In addition, the data reported in the present study were primarily intervened on the basis of the timeline selected from 1 January 2000 to 31 October 2021. The whole framework was designed substantially based on key terms and studies selected by virtue of their relevance to our investigations. RESULTS: Findings suggested that channels of free radicals, such as transition metal accumulation, and genetic factors are mainly accountable for the redox imbalance that assist to understand better the pathogenesis of AD and incorporate new therapeutic approaches. Moreover, TREM2 might elicit a protective function for microglia in AD. NO causes an increase in oxidative stress and mitochondrial damage, compromising cellular integrity and viability. The study also explored that the gut and CNS communicate with one another and that regulating gut commensal flora might be a viable therapeutic for neurodegenerative illnesses like AD. CONCLUSION: There are presently no viable therapies for Alzheimer's disease, but recent breakthroughs in our knowledge of the disease's pathophysiology may aid in the discovery of prospective therapeutic targets.

Bioisosteres of Indomethacin as Inhibitors of Aldo-Keto Reductase 1C3.

Aldo-keto reductase 1C3 (AKR1C3) is an attractive target in drug design for its role in resistance to anticancer therapy. Several nonsteroidal anti-inflammatory drugs such as indomethacin are known to inhibit AKR1C3 in a nonselective manner because of COX-off target effects. Here we designed two indomethacin analogues by proposing a bioisosteric connection between the indomethacin carboxylic acid function and either hydroxyfurazan or hydroxy triazole rings. Both compounds were found to target AKR1C3 in a selective manner. In particular, hydroxyfurazan derivative is highly selective for AKR1C3 over the 1C2 isoform (up to 90-times more) and inactive on COX enzymes. High-resolution crystal structure of its complex with AKR1C3 shed light onto the binding mode of the new inhibitors. In cell-based assays (on colorectal and prostate cancer cells), the two indomethacin analogues showed higher potency than indomethacin. Therefore, these two AKR1C3 inhibitors can be used to provide further insight into the role of AKR1C3 in cancer.

Hydroxyazole scaffold-based Plasmodium falciparum dihydroorotate dehydrogenase inhibitors: Synthesis, biological evaluation and X-ray structural studies.

Plasmodium falciparum dihydroorotate dehydrogenase (PfDHODH) has been clinically validated as a target for antimalarial drug discovery, as a triazolopyrimidine class inhibitor (DSM265) is currently undergoing clinical development. Here, we have identified new hydroxyazole scaffold-based PfDHODH inhibitors belonging to two different chemical series. The first series was designed by a scaffold hopping strategy that exploits the use of hydroxylated azoles. Within this series, the hydroxythiadiazole 3 was identified as the best selective PfDHODH inhibitor (IC50 12.0 µM). The second series was designed by modulating four different positions of the hydroxypyrazole scaffold. In particular, hydroxypyrazoles 7e and 7f were shown to be active in the low µM range (IC50 2.8 and 5.3 µM, respectively). All three compounds, 3, 7e and 7f showed clear selectivity over human DHODH (IC50 > 200 µM), low cytotoxicity, and retained micromolar activity in P. falciparum-infected erythrocytes. The crystallographic structures of PfDHODH in complex with compounds 3 and 7e proved their binding mode, supplying essential data for future optimization of these scaffolds.

Targeting Myeloid Differentiation Using Potent 2-Hydroxypyrazolo[1,5- a]pyridine Scaffold-Based Human Dihydroorotate Dehydrogenase Inhibitors.

Human dihydroorotate dehydrogenase ( hDHODH) catalyzes the rate-limiting step in de novo pyrimidine biosynthesis, the conversion of dihydroorotate to orotate. hDHODH has recently been found to be associated with acute myelogenous leukemia, a disease for which the standard of intensive care has not changed over decades. This work presents a novel class of hDHODH inhibitors, which are based on an unusual carboxylic group bioisostere 2-hydroxypyrazolo[1,5- a]pyridine, that has been designed starting from brequinar, one of the most potent hDHODH inhibitors. A combination of structure-based and ligand-based strategies produced compound 4, which shows brequinar-like hDHODH potency in vitro and is superior in terms of cytotoxicity and immunosuppression. Compound 4 also restores myeloid differentiation in leukemia cell lines at concentrations that are one log digit lower than those achieved in experiments with brequinar. This Article reports the design, synthesis, SAR, X-ray crystallography, biological assays, and physicochemical characterization of the new class of hDHODH inhibitors.

Substrate-bound outward-open structure of a Na+-coupled sialic acid symporter reveals a new Na+ site.

Many pathogenic bacteria utilise sialic acids as an energy source or use them as an external coating to evade immune detection. As such, bacteria that colonise sialylated environments deploy specific transporters to mediate import of scavenged sialic acids. Here, we report a substrate-bound 1.95 Å resolution structure and subsequent characterisation of SiaT, a sialic acid transporter from Proteus mirabilis. SiaT is a secondary active transporter of the sodium solute symporter (SSS) family, which use Na+ gradients to drive the uptake of extracellular substrates. SiaT adopts the LeuT-fold and is in an outward-open conformation in complex with the sialic acid N-acetylneuraminic acid and two Na+ ions. One Na+ binds to the conserved Na2 site, while the second Na+ binds to a new position, termed Na3, which is conserved in many SSS family members. Functional and molecular dynamics studies validate the substrate-binding site and demonstrate that both Na+ sites regulate N-acetylneuraminic acid transport.

Potent and selective aldo-keto reductase 1C3 (AKR1C3) inhibitors based on the benzoisoxazole moiety: application of a bioisosteric scaffold hopping approach to flufenamic acid.

The aldo-keto reductase 1C3 (AKR1C3) isoform plays a vital role in the biosynthesis of androgens and is considered an attractive target in prostate cancer (PCa). No AKR1C3-targeted agent has to date been approved for clinical use. Flufenamic acid and indomethacine are non-steroidal anti-inflammatory drugs known to inhibit AKR1C3 in a non-selective manner as COX off-target effects are also observed. Recently, we employed a scaffold hopping approach to design a new class of potent and selective AKR1C3 inhibitors based on a N-substituted hydroxylated triazole pharmacophore. Following a similar strategy, we designed a new series focused around an acidic hydroxybenzoisoxazole moiety, which was rationalised to mimic the benzoic acid role in the flufenamic scaffold. Through iterative rounds of drug design, synthesis and biological evaluation, several compounds were discovered to target AKR1C3 in a selective manner. The most promising compound of series (6) was found to be highly selective (up to 450-fold) for AKR1C3 over the 1C2 isoform with minimal COX1 and COX2 off-target effects. Other inhibitors were obtained modulating the best example of hydroxylated triazoles we previously presented. In cell-based assays, the most promising compounds of both series reduced the cell proliferation, prostate specific antigen (PSA) and testosterone production in AKR1C3-expressing 22RV1 prostate cancer cells and showed synergistic effect when assayed in combination with abiraterone and enzalutamide. Structure determination of AKR1C3 co-crystallized with one representative compound from each of the two series clearly identified both compounds in the androstenedione binding site, hence supporting the biochemical data.

"Just a spoonful of sugar...": import of sialic acid across bacterial cell membranes.

Eukaryotic cell surfaces are decorated with a complex array of glycoconjugates that are usually capped with sialic acids, a large family of over 50 structurally distinct nine-carbon amino sugars, the most common member of which is N-acetylneuraminic acid. Once made available through the action of neuraminidases, bacterial pathogens and commensals utilise host-derived sialic acid by degrading it for energy or repurposing the sialic acid onto their own cell surface to camouflage the bacterium from the immune system. A functional sialic acid transporter has been shown to be essential for the uptake of sialic acid in a range of human bacterial pathogens and important for host colonisation and persistence. Here, we review the state-of-play in the field with respect to the molecular mechanisms by which these bio-nanomachines transport sialic acids across bacterial cell membranes.

Antiurolithiatic Potential of Neeri against Calcium-Oxalate Stones by Crystallization Inhibition, Free Radicals Scavenging, and NRK-52E Cell Protection from Oxalate Injury.

BACKGROUND: Neeri is a well-established polyherbal formulation prescribed for renal stones by the physicians but has not been experimentally evaluated for its antiurolithiatic potential using cell-lines. OBJECTIVE: This study is aimed to scientifically substantiate the antiurolithiatic effect of Neeri extract (NRE) through calcium oxalate (CaOx) crystallization inhibition, scavenging of free radicals, and protection of renal tubular epithelial NRK-52E cells from oxalate-induced injury. MATERIALS AND METHODS: The crystallization inhibition was studied by turbidimetric assay while the free radical scavenging potential was determined for superoxide and nitric oxide (NO) radicals. The cytoprotective effect against oxalate-induced injury was assessed by estimating lactate dehydrogenase (LDH) leakage and determining cell viability using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. RESULTS: NRE significantly inhibited the CaOx crystallization in a concentration-dependent manner and also scavenged superoxide (IC50 302.88 µg/ml) and NO (IC50 300.45 µg/ml) free radicals. It did not show any significant cytotoxicity for NRK-52E cells till the highest dose (500 µg/ml) and found to be safe. When NRK-52E cells, injured by exposing to oxalate crystals for 24 h, were treated with NRE, it appreciably prevented the cell injury in a dose-dependent manner. It significantly decreased the elevated LDH leakage toward normal range and improved renal cell viability (82.37% ± 0.87%), hence, prevented growth and retention of crystals. CONCLUSION: The experimental findings concluded that Neeri is a potent antiurolithiatic formulation that inhibited CaOx crystallization and prevented tubular retention of crystals by protecting the renal cells against oxalate-induced injury as well as reducing the oxidative stress by scavenging free radicals. SUMMARY: Neeri extract significantly (P < 0.001) inhibited the in vitro crystallization (88.11% ± 7.70%) of calcium oxalateIt reduced oxidative stress by scavenging superoxide and nitric oxide free radicalsIt significantly (P < 0.001) improved the cell viability by inhibiting the leakage of lactate dehydrogenase in a dose-dependent manner. Abbreviations used: Ac: Absorbance of control, At: Absorbance of test, ANOVA: Analysis of variance, CaOx: Calcium oxalate, DMEM: Dulbecco's Modified Eagle's Medium, DMSO: Dimethyl sulfoxide, EDTA: Ethylenediaminetetraacetic acid, FBS: Fetal bovine serum, INT: Iodonitrotetrazolium, LDH: Lactate dehydrogenase, M: Molar, ml: Milliliter, mM: Millimolar, MTT: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, NAD: Nicotinamide adenine dinucleotide, NADPH: Nicotinamide adenine dinucleotide phosphate, NBT: Nitro blue tetrazolium, nm: Nanometer, NO: Nitric oxide, NRE: Neeri extract, PMS: Phenazine methosulfate, ROS: Reactive oxygen species, Sc: Slope of the graph of control, SEM: Standard error of mean, Si: Slope of the graph with inhibitor, U/I: International unit, mg: Microgram, ml: Microliter.

Crystal structure of N-acetylmannosamine kinase from Fusobacterium nucleatum.

Sialic acids comprise a varied group of nine-carbon amino sugars that are widely distributed among mammals and higher metazoans. Some human commensals and bacterial pathogens can scavenge sialic acids from their environment and degrade them for use as a carbon and nitrogen source. The enzyme N-acetylmannosamine kinase (NanK; EC 2.7.1.60) belongs to the transcriptional repressors, uncharacterized open reading frames and sugar kinases (ROK) superfamily. NanK catalyzes the second step of the sialic acid catabolic pathway, transferring a phosphate group from adenosine 5'-triphosphate to the C6 position of N-acetylmannosamine to generate N-acetylmannosamine 6-phosphate. The structure of NanK from Fusobacterium nucleatum was determined to 2.23 Šresolution by X-ray crystallography. Unlike other NanK enzymes and ROK family members, F. nucleatum NanK does not have a conserved zinc-binding site. In spite of the absence of the zinc-binding site, all of the major structural features of enzymatic activity are conserved.

Design, synthesis, biological evaluation and X-ray structural studies of potent human dihydroorotate dehydrogenase inhibitors based on hydroxylated azole scaffolds.

A new generation of potent hDHODH inhibitors designed by a scaffold-hopping replacement of the quinolinecarboxylate moiety of brequinar, one of the most potent known hDHODH inhibitors, is presented here. Their general structure is characterized by a biphenyl moiety joined through an amide bridge with an acidic hydroxyazole scaffold (hydroxylated thiadiazole, pyrazole and triazole). Molecular modelling suggested that these structures should adopt a brequinar-like binding mode involving interactions with subsites 1, 2 and 4 of the hDHODH binding site. Initially, the inhibitory activity of the compounds was studied on recombinant hDHODH. The most potent compound of the series in the enzymatic assays was the thiadiazole analogue 4 (IC50 16 nM). The activity was found to be dependent on the fluoro substitution pattern at the biphenyl moiety as well as on the choice/substitution of the heterocyclic ring. Structure determination of hDHODH co-crystallized with one representative compound from each series (4, 5 and 6) confirmed the brequinar-like binding mode as suggested by modelling. The specificity of the observed effects of the compound series was tested in cell-based assays for antiproliferation activity using Jurkat cells and PHA-stimulated PBMC. These tests were also verified by addition of exogenous uridine to the culture medium. In particular, the triazole analogue 6 (IC50 against hDHODH: 45 nM) exerted potent in vitro antiproliferative and immunosuppressive activity without affecting cell survival.

Multiple enzymatic activities of ParB/Srx superfamily mediate sexual conflict among conjugative plasmids.

Conjugative plasmids are typically locked in intergenomic and sexual conflicts with co-resident rivals, whose translocation they block using fertility inhibition factors (FINs). We describe here the first crystal structure of an enigmatic FIN Osa deployed by the proteobacterial plasmid pSa. Osa contains a catalytically active version of the ParB/Sulfiredoxin fold with both ATPase and DNase activity, the latter being regulated by an ATP-dependent switch. Using the Agrobacterium tumefaciens VirB/D4 type IV secretion system (T4SS), a relative of the conjugative T4SS, we demonstrate that catalytically active Osa blocks T-DNA transfer into plants. With a partially reconstituted T4SS in vitro, we show that Osa degrades T-DNA in the T-DNA-VirD2 complex before its translocation. Further, we present evidence for conservation and interplay between ATPase and DNase activities throughout the ParB/Sulfiredoxin fold, using other members of the family, namely P1 ParB and RK2 KorB, which have general functional implications across diverse biological contexts.

Structural and mechanistic insights into the bacterial amyloid secretion channel CsgG.

Curli are functional amyloid fibres that constitute the major protein component of the extracellular matrix in pellicle biofilms formed by Bacteroidetes and Proteobacteria (predominantly of the α and γ classes). They provide a fitness advantage in pathogenic strains and induce a strong pro-inflammatory response during bacteraemia. Curli formation requires a dedicated protein secretion machinery comprising the outer membrane lipoprotein CsgG and two soluble accessory proteins, CsgE and CsgF. Here we report the X-ray structure of Escherichia coli CsgG in a non-lipidated, soluble form as well as in its native membrane-extracted conformation. CsgG forms an oligomeric transport complex composed of nine anticodon-binding-domain-like units that give rise to a 36-stranded ß-barrel that traverses the bilayer and is connected to a cage-like vestibule in the periplasm. The transmembrane and periplasmic domains are separated by a 0.9-nm channel constriction composed of three stacked concentric phenylalanine, asparagine and tyrosine rings that may guide the extended polypeptide substrate through the secretion pore. The specificity factor CsgE forms a nonameric adaptor that binds and closes off the periplasmic face of the secretion channel, creating a 24,000 Å(3) pre-constriction chamber. Our structural, functional and electrophysiological analyses imply that CsgG is an ungated, non-selective protein secretion channel that is expected to employ a diffusion-based, entropy-driven transport mechanism.

Secretion and functional display of fusion proteins through the curli biogenesis pathway.

Curli are functional amyloids expressed as fibres on the surface of Enterobacteriaceae. Contrary to the protein misfolding events associated with pathogenic amyloidosis, curli are the result of a dedicated biosynthetic pathway. A specialized transporter in the outer membrane, CsgG, operates in conjunction with the two accessory proteins CsgE and CsgF to secrete curlin subunits to the extracellular surface, where they nucleate into cross-beta strand fibres. Here we investigate the substrate tolerance of the CsgG transporter and the capability of heterologous sequences to be built into curli fibres. Non-native polypeptides ranging up to at least 260 residues were exported when fused to the curli subunit CsgA. Secretion efficiency depended on the folding properties of the passenger sequences, with substrates exceeding an approximately 2 nm transverse diameter blocking passage through the transport channel. Secretion of smaller passengers was compatible with prior DsbA-mediated disulphide bridge formation in the fusion partner, indicating that CsgG is capable of translocating non-linear polypeptide stretches. Using fusions we further demonstrate the exported or secreted heterologous passenger proteins can attain their native, active fold, establishing curli biogenesis pathway as a platform for the secretion and surface display of small heterologous proteins.

Crystallization and preliminary X-ray crystallographic analysis of the curli transporter CsgG.

Gram-negative bacteria have eight known protein secretion systems. The type-VIII secretion system, also known as the curli biosynthesis system, is responsible for the formation of aggregative fibres known in Escherichia coli as curli. Curli are extracellular proteinaceous fibres primarily involved in bacterial biofilm formation and attachment to nonbiotic surfaces. The secretion of curli subunits depends on a dedicated lipoprotein, CsgG, which is found to form an oligomeric secretion channel in the outer membrane. A nonlipidated mutant of CsgG was expressed and crystallized in a soluble form. The crystals diffracted to 3.15 Å resolution and belong to space group P1 with a unit cell containing a predicted 16 molecules per asymmetric unit.

The mannose-specific lectin domains of Flo1p from Saccharomyces cerevisiae and Lg-Flo1p from S. pastorianus: crystallization and preliminary X-ray diffraction analysis of the adhesin-carbohydrate complexes.

Flo1p and Lg-Flo1p are two cell-wall adhesins belonging to the Flo (flocculation) protein family from the yeasts Saccharomyces cerevisiae and S. pastorianus. The main function of these modular proteins endowed with calcium-dependent lectin activity is to mediate cell-cell adhesion events during yeast flocculation, a process which is well known at the cellular level but still not fully characterized from a molecular perspective. Recently, structural features of the N-terminal Flo lectin domains, including the N-terminal domain of Lg-Flo1p (N-Lg-Flo1p), and their interactions with carbohydrate molecules have been investigated. However, structural data concerning the N-terminal domain of Flo1p (N-Flo1p), which is the most specific among the Flo proteins, are missing and information about the N-Lg-Flo1p-carbohydrate interaction still lacks detailed structural insight. Here, the crystallization and preliminary X-ray characterization of the apo form and the mannose complex of N-Flo1p and X-ray analysis of N-Lg-Flo1p crystals soaked in α-1,2-mannobiose are reported. The N-Flo1p crystals diffracted to a resolution of 1.43 Å in the case of the apo form and to 2.12 Å resolution for the mannose complex. Both crystals were orthorhombic and belonged to space group P212121, with one molecule in the asymmetric unit. The N-Lg-Flo1p-α-1,2-mannobiose complex crystal diffracted to 1.73 Å resolution and belonged to the monoclinic space group P1211 with two molecules in the asymmetric unit.

Inhibition of MAO and GABA: probable mechanisms for antidepressant-like activity of Nardostachys jatamansi DC. in mice.

Ethanolic extract (100, 200 and 400 mg/kg, po) of N. jatamansi administered for 14 successive days to Swiss young albino mice (either sex) produced significant antidepressant-like effect in both tail suspension and forced swim tests. The efficacy of the extract was found to be comparable to imipramine (15 mg/kg, po) and sertraline (20 mg/kg, po). Ethanolic extract (200 mg/kg, po) did not show any significant change on locomotor activity of mice as compared to control; hence it did not produce any motor effects. Further, the extract decreased the whole brain MAO-A and MAO-B activities as compared tocontrol, thus increased the levels of monoamines. The antidepressant effect of the extract was also significantly reversed by pretreatment of animals with baclofen (GABAB agonist); when tested in tail suspension test. The results suggested that the antidepressant-like effect of the extract may also be due to interaction with GABAB receptors, resulting in decrease in the levels of GABA in mouse brain. Thus, the extract may have potential therapeutic value for the management of mental depression.