Mechanistic Investigation of Thiazole-Based Pyruvate Kinase M2 Inhibitor Causing Tumor Regression in Triple-Negative Breast Cancer.

Triple-negative breast cancer (TNBC) is a deadly breast cancer with a poor prognosis. Pyruvate kinase M2 (PKM2), a key rate-limiting enzyme in glycolysis, is abnormally highly expressed in TNBC. Overexpressed PKM2 amplifies glucose uptake, enhances lactate production, and suppresses autophagy, thereby expediting the progression of oncogenic processes. A high mortality rate demands novel chemotherapeutic regimens at once. Herein, we report the rational development of an imidazopyridine-based thiazole derivative 7d as an anticancer agent inhibiting PKM2. Nanomolar range PKM2 inhibitors with favorable drug-like properties emerged through enzyme assays. Experiments on two-dimensional (2D)/three-dimensional (3D) cell cultures, lactate release assay, surface plasmon resonance (SPR), and quantitative real-time polymerase chain reaction (qRT-PCR) validated 7d preclinically. In vivo, 7d outperformed lapatinib in tumor regression. This investigation introduces a lead-based approach characterized by its clear-cut chemistry and robust efficacy in designing an exceptionally potent inhibitor targeting PKM2, with a focus on combating TNBC.

Comprehensive characterization and preclinical assessment of an imidazopyridine-based anticancer lead molecule.

Imidazopyridine scaffold holds significant pharmacological importance in the treatment of cancer. An in-house synthesized imidazopyridine-based molecule was found to have promising anticancer activity against breast cancer, lung cancer, and colon cancer. The molecule is an inhibitor of pyruvate kinase M2, the enzyme that elevates tumor growth, metastasis and chemoresistance by directly controlling tumor cell metabolism. Screening of the physicochemical properties of any lead molecules is essential to avoid failure in late-stage drug development. In this research, the physicochemical properties of the molecule including log P, log D, pKa, and plasma protein binding were assessed to check its drug-likeness. Plasma and metabolic stability of the molecule were also evaluated. Moreover, pharmacokinetic profiles of the lead molecule in Sprague-Dawley rats and in vitro metabolite identification studies were also performed. Finally, an in silico software, Pro-Tox-II, was used to predict toxicity of the molecule and its metabolites. Log P, Log D (pH 7.4), pKa, and plasma protein binding of the molecule were found to be 2.03%, 2.42%, 10.4%, and 98%, respectively. The molecule was stable in plasma and metabolic conditions. A total of nine new metabolites were identified and characterized. Cmax and t½ of this molecule were found to be 4016 ± 313.95 ng/mL and 9.57 ± 3.05 h, respectively. Based on the previously reported study and this finding, the molecule can be considered as a promising anticancer lead with potential drug-likeness properties. Further preclinical and clinical drug discovery studies may be initiated in continuation of this study in search of a potential anticancer lead.

Roadmap to Pyruvate Kinase M2 Modulation - A Computational Chronicle.

Pyruvate kinase M2 (PKM2) has surfaced as a potential target for anti-cancer therapy. PKM2 is known to be overexpressed in the tumor cells and is a critical metabolic conduit in supplying the augmented bioenergetic demands of the recalcitrant cancer cells. The presence of PKM2 in structurally diverse tetrameric as well as dimeric forms has opened new avenues to design novel modulators. It is also a truism to state that drug discovery has advanced significantly from various computational techniques like molecular docking, virtual screening, molecular dynamics, and pharmacophore mapping. The present review focuses on the role of computational tools in exploring novel modulators of PKM2. The structural features of various isoforms of PKM2 have been discussed along with reported modulators. An extensive analysis of the structure-based and ligand- based in silico methods aimed at PKM2 modulation has been conducted with an in-depth review of the literature. The role of advanced tools like QSAR and quantum mechanics has been established with a brief discussion of future perspectives.

PROTACting the kinome with covalent warheads.

The dawn of targeted degradation using proteolysis-targeting chimeras (PROTACs) against recalcitrant proteins has prompted numerous efforts to develop complementary drugs. Although many of these are specifically directed against undruggable proteins, there is increasing interest in small molecule-based PROTACs that target intracellular pathways, and some have recently entered clinical trials. Concurrently, small molecule-based PROTACs that target protumorigenic pathways in cancer cells, the tumor microenvironment (TME), and angiogenesis have been found to have potent effects that synergize with the action of antibodies. This has led to the augmentation of PROTACs with variable substitution patterns. Several combinations with small molecules targeting undruggable proteins are now under clinical investigation. In this review, we discuss the recent milestones achieved as well as challenges encountered in this area of drug development, as well as our opinion on the best path forward.

LC/Q-TOF MS and LC/QQQ MS based bioanalysis of a new ferrocene derivative as a potential anticancer lead with promising drug-like characteristics.

Pyrazolopyrimidine ring present in various approved drugs is reported to target the tyrosine kinase receptor. A new pyrazolopyrimidine ferrocene derivative, which targets tumor pyruvate kinase M2 showed an impressive antiproliferative profile against human oral squamous cell carcinoma cell line CAL27 assessed using Alamar blue assay. In line with the lead optimization process, the molecule was studied for physicochemical properties where a bioanalytical method has been developed in plasma on liquid chromatography-mass spectrometry and validated following the USFDA bioanalytical method validation guideline. Plasma stability and plasma protein binding potential of the molecule have been evaluated. All the major metabolites of the compound have been identified through in vitro metabolite study employing rat liver microsome, human liver microsome, and human S9 fractions. The in silico toxicity profile of the metabolites was assessed using ProTox II software. Log P, Log D, and pKa of the molecule were found to be 4.5, 5, and 12, respectively. The molecule was found to be quite stable in plasma and have a moderate affinity towards plasma proteins (about 75 % binding). Four major metabolites have been identified and characterized by UHPLCQ-TOF-MS. The metabolites were found to have a moderate safety profile. The validated bioanalytical method and the metabolic pathway will be useful for future clinical studies and to assess the safety profile of the molecule. The finding of this study may also be useful in analyzing the desired drug-like properties through bioanalysis while designing new chemical entities based on metallocenes.

Objective assessment of adrenocortical carcinoma driver genes and their correlation with tumor pyruvate kinase M2.

Glandular cancers have a significant share of the total cancer patients all over the world. In the case of adrenocortical carcinomas (ACCs), although the benign form is more frequent and common, the malignant form provides a very less percentage of patients with five or more than five years of survival rate. There are gene alterations that are involved as a crucial factor behind the occurrence of ACCs. Out of these, the most prominent genetic alterations (PRKAR-1A, CTNNB1, ZNRF3, TP53, CCNE1 and TERF2 genes) are linked with a glycolytic enzyme pyruvate kinase M2 (PKM2), which converts phosphoenolpyruvate (PEP) to pyruvate in the glycolytic pathway. The involvementof PKM2 renders a cumulative effect through different pathways that may result in the onset of ACCs. Thus, this review aims to establish a link between ACCs, alterations of specific genes and PKM2.

Design and In-silico Screening of Peptide Nucleic Acid (PNA) Inspired Novel Pronucleotide Scaffolds Targeting COVID-19.

INTRODUCTION: The outburst of the novel coronavirus COVID-19, at the end of December 2019 has turned into a pandemic, risking many human lives. The causal agent being SARS-CoV-2, a member of the long-known Coronaviridae family, is a positive-sense single-stranded enveloped virus and closely related to SARS-CoV. It has become the need of the hour to understand the pathophysiology of this disease, so that drugs, vaccines, treatment regimens and plausible therapeutic agents can be produced. METHODS: In this regard, recent studies uncovered the fact that the viral genome of SARS-CoV-2 encodes non-structural proteins like RNA-dependent RNA polymerase (RdRp) which is an important tool for its transcription and replication process. A large number of nucleic acid-based anti-viral drugs are being repurposed for treating COVID-19 targeting RdRp. Few of them are at the advanced stage of clinical trials, including remdesivir. While performing a detailed investigation of the large set of nucleic acid-based drugs, we were surprised to find that the synthetic nucleic acid backbone has been explored very little or rare. RESULTS: We designed scaffolds derived from peptide nucleic acid (PNA) and subjected them to in- -silico screening systematically. These designed molecules have demonstrated excellent binding towards RdRp. Compound 12 was found to possess a similar binding affinity as remdesivir with comparable pharmacokinetics. However, the in-silico toxicity prediction indicates that compound 12 may be a superior molecule which can be explored further due to its excellent safety-profile with LD50 12,000mg/kg as opposed to remdesivir (LD50 =1000mg/kg). CONCLUSION: Compound 12 falls in the safe category of class 6. Synthetic feasibility, equipotent binding and very low toxicity of this peptide nucleic acid-derived compound can make it a leading scaffold to design, synthesize and evaluate many similar compounds for the treatment of COVID-19.

A molecular perspective for the use of type IV tyrosine kinase inhibitors as anticancer therapeutics.

Tyrosine kinases are enzymes that can transfer a phosphate group from ATP to a specific protein tyrosine, serine or threonine residue within a cell, operating as a switch that can turn 'on' and 'off' causing different physiological alterations in the body. Mutated kinases have been shown to display an equilibrium shift toward the activated state. Types I-III have been studied intensively leading to drugs like imatinib (type II), cobimetinib (type III), among others. It is the same scenario for types V-VII; however, there is a lacuna in information regarding type IV inhibitors, although recently some advances have surfaced. This review aims to accumulate the knowledge gained so far about type IV inhibitors.

Potassium tert-butoxide mediated C-C, C-N, C-O and C-S bond forming reactions.

Potassium tertiary butoxide (KOtBu) mediated constructions of C-C, C-O, C-N, and C-S bonds are reviewed with special emphasis on their synthetic applications. KOtBu can be used to perform reactions already known to be carried out using transition metals, but it has advantages in terms of environmental congruence and economic cost. KOtBu is widely employed in organic synthesis to mediate the construction of C-C, C-O, C-N, C-S and miscellaneous bonds in good to excellent yields. Synthetic uses of KOtBu in coupling, alkylation, arylation, α-phenylation, cyclization, Heck-type, annulation, photo-arylation, aromatic-substitution, amidation, and silylation reactions are summarized and discussed. The mechanisms through which KOtBu carries out a specific reaction are also discussed. One of the goals of this review is to attract the attention of chemists as to the benefits of using KOtBu as an environmentally benign alternative to transition metals and its applications in the construction of chemical bonds with predominant importance in organic synthesis. This review completely covers the synthetic protocols that have been performed using KOtBu in the last two decades.

Old Drugs with New Tricks: Paradigm in Drug Development Pipeline for Alzheimer's Disease.

The most common reason behind dementia is Alzheimer's disease (AD) and it is predicted to be the third life-threatening disease apart from stroke and cancer for the geriatric population. Till now, only four drugs are available on the market for symptomatic relief. The complex nature of disease pathophysiology and lack of concrete evidence of molecular targets are the major hurdles for developing a new drug to treat AD. The rate of attrition of many advanced drugs at clinical stages makes the de novo discovery process very expensive. Alternatively, Drug Repurposing (DR) is an attractive tool to develop drugs for AD in a less tedious and economic way. Therefore, continuous efforts are being made to develop a new drug for AD by repurposing old drugs through screening and data mining. For example, the survey in the drug pipeline for Phase III clinical trials (till February 2019) consists of 27 candidates, and around half of the number are drugs which have already been approved for other indications. Although in the past, the drug repurposing process for AD has been reviewed in the context of disease areas, molecular targets, there is no systematic review of repurposed drugs for AD from the recent drug development pipeline (2019-2020). In this manuscript, we have reviewed the clinical candidates for AD with emphasis on their development history, including molecular targets and the relevance of the target for AD.

Ultrashort Peptides-A Glimpse into the Structural Modifications and Their Applications as Biomaterials.

Because of their commanding properties, ultrashort and short peptides are gaining significance as viable candidates for molecular self-assembly, which is a naturally inspired approach for developing supramolecular structures and can be used to design various strategies of significance in the field of biomaterials. Self-assembly of biomolecules like proteins, lipids, and nucleic acids is observed in living organisms, various biological-process-based examples like amyloid-ß plaque formation, lipid bilayer assembly, and the complementary binding of the nucleotide bases of nucleic acids involve self-assembly. Among all biomolecules, peptide-based self-assembly has the advantage of the availability of the source, peptides can be easily synthesized or obtained from the natural degradation process and can be engineered to modulate their action, making them an area of immense interest for research. Multiple modification options provide a wide area for the engineering of amino acid sequences. Understanding of the amino acid residues with their existing properties and modified properties is very helpful for further improvements. Computational approaches like molecular dynamics simulations provide atomistic-level insight into the self-assembly process, by which newer physical-chemical modifications can be planned. Virtual screening of the peptides on the basis of their properties and probability for the desired activity are helpful as well. Engineered and programmed peptides have been reported for various applications like drug delivery and target specific formulations. A combined approach of computational and experimental studies is helpful to understand and optimize the self-assembly process and mechanism at the atomic level. These self-assembled ultrashort peptides have been used in a wide range of applications from hydrogels to drug delivery agents, biosensors, emulsifiers, and so on.