Spleen tyrosine kinase (SYK): an emerging target for the assemblage of small molecule antitumor agents.

INTRODUCTION: Spleen tyrosine kinase (SYK), a nonreceptor tyrosine kinase, has emerged as a vital component in the complex symphony of cancer cell survival and division. SYK activation (constitutive) is documented in various B-cell malignancies, and its inhibition induces programmed cell death. In some instances, it also acts as a tumor suppressor. AREAS COVERED: Involvement of the SYK in the cancer growth, specifically in the progression of chronic lymphocytic leukemia (CLL), diffuse large B cell lymphomas (DLBCLs), acute myeloid leukemia (AML), and multiple myeloma (MM) is discussed. Therapeutic strategies to target SYK in cancer, including investigational SYK inhibitors, combinations of SYK inhibitors with other drugs targeting therapeutically relevant targets, and recent advancements in constructing new structural assemblages as SYK inhibitors, are also covered. EXPERT OPINION: The SYK inhibitor field is currently marred by the poor translation rate of SYK inhibitors from preclinical to clinical studies. Also, dose-limited toxicities associated with the applications of SYK inhibitors have been evidenced. Thus, the development of new SYK inhibitory structural templates is in the need of the hour. To accomplish the aforementioned, interdisciplinary teams should incessantly invest efforts to expand the size of the armory of SYK inhibitors.

Leveraging a rationally designed veliparib-based anilide eliciting anti-leukemic effects for the design of pH-responsive polymer nanoformulation.

Careful recruitment of the components of the HDAC inhibitory template culminated in veliparib-based anilide 8 that elicited remarkable cell growth inhibitory effects against HL-60 cell lines mediated via dual modulation of PARP [(IC50 (PARP1) = 0.02 nM) and IC50 (PARP2) = 1 nM)] and HDACs (IC50 value = 0.05, 0.147 and 0.393 µM (HDAC1, 2 and 3). Compound 8 downregulated the expression levels of signatory biomarkers of PARP and HDAC inhibition. Also, compound 8 arrested the cell cycle at the G0/G1 phase and induced autophagy. Polymer nanoformulation (mPEG-PCl copolymeric micelles loaded with compound 8) was prepared by the nanoprecipitation technique. The mPEG-PCL diblock copolymer was prepared by ring-opening polymerization method using stannous octoate as a catalyst. The morphology of the compound 8@mPEG-PCL was examined using TEM and the substance was determined to be monodispersed, spherical in form, and had an average diameter of 138 nm. The polymer nanoformulation manifested pH-sensitive behaviour as a greater release of compound 8 was observed at 6.2 pH as compared to 7.4 pH mimicking physiological settings. The aforementioned findings indicate that the acidic pH of the tumour microenvironment might stimulate the nanomedicine release which in turn can attenuate the off-target effects precedentially claimed to be associated with HDAC inhibitors.

Recent advances and future directions on small molecule VEGFR inhibitors in oncological conditions.

"A journey of mixed emotions" is a quote that best describes the progress chart of vascular endothelial growth factor receptor (VEGFR) inhibitors as cancer therapeutics in the last decade. Exhilarated with the Food and Drug Administration (FDA) approvals of numerous VEGFR inhibitors coupled with the annoyance of encountering the complications associated with their use, drug discovery enthusiasts are on their toes with an unswerving determination to enhance the rate of translation of VEGFR inhibitors from preclinical to clinical stage. The recently crafted armory of VEGFR inhibitors is a testament to their growing dominance over other antiangiogenic therapies for cancer treatment. This review perspicuously underscores the earnest attempts of the researchers to extract the antiproliferative potential of VEGFR inhibitors through the design of mechanistically diverse structural assemblages. Moreover, this review encompasses sections on structural/molecular properties and physiological functions of VEGFR, FDA-approved VEGFR inhibitors, and hurdles restricting the activity range/clinical applicability of VEGFR targeting antitumor agents. In addition, tactics to overcome the limitations of VEGFR inhibitors are discussed. A clear-cut viewpoint transmitted through this compilation can provide practical directions to push the cart of VEGFR inhibitors to advanced-stage clinical investigations in diverse malignancies.

Flavone-based dual PARP-Tubulin inhibitor manifesting efficacy against endometrial cancer.

Structural tailoring of the flavone framework (position 7) via organopalladium-catalyzed C-C bond formation was attempted in this study. The impact of substituents with varied electronic effects (phenyl ring, position 2 of the benzopyran scaffold) on the antitumor properties was also assessed. Resultantly, the efforts yielded a furyl arm bearing benzopyran possessing a 4-fluoro phenyl ring (position 2) (14) that manifested a magnificent antitumor profile against the Ishikawa cell lines mediated through dual inhibition of PARP and tubulin [(IC50 (PARP1) = 74 nM, IC50 (PARP2) = 109 nM) and tubulin (IC50 = 1.4 µM)]. Further investigations confirmed the ability of 14 to induce apoptosis as well as autophagy and cause cell cycle arrest at the G2/M phase. Overall, the outcome of the study culminated in a tractable dual PARP-tubulin inhibitor endowed with an impressive activity profile against endometrial cancer.

N-Heterocycle based Degraders (PROTACs) Manifesting Anticancer Efficacy: Recent Advances.

Proteolysis Targeting Chimeras (PROTACs) technology has emerged as a promising strategy for the treatment of undruggable therapeutic targets. Researchers have invested a great effort in developing druggable PROTACs; however, the problems associated with PROTACs, including poor solubility, metabolic stability, cell permeability, and pharmacokinetic profile, restrict their clinical utility. Thus, there is a pressing need to expand the size of the armory of PROTACs which will escalate the chances of pinpointing new PROTACs with optimum pharmacokinetic and pharmacodynamics properties. N- heterocycle is a class of organic frameworks that have been widely explored to construct new and novel PROTACs. This review provides an overview of recent efforts of medicinal chemists to develop N-heterocycle-based PROTACs as effective cancer therapeutics. Specifically, the recent endeavors centred on the discovery of PROTACs have been delved into various classes based on the E3 ligase they target (MDM2, IAP, CRBN, and other E3 ligases). Mechanistic insights revealed during the biological assessment of recently furnished Nheterocyclic- based PROTACs constructed via the utilization of ligands for various E3 ligases have been discussed.

Small molecule tractable PARP inhibitors: Scaffold construction approaches, mechanistic insights and structure activity relationship.

Diverse drug design strategies viz. molecular hybridization, substituent installation, scaffold hopping, isosteric replacement, high-throughput screening, induction and separation of chirality, structure modifications of phytoconstituents and use of structural templates have been exhaustively leveraged in the last decade to load the chemical toolbox of PARP inhibitors. Resultantly, numerous promising scaffolds have been pinpointed that in turn have led to the resuscitation of the credence to PARP inhibitors as cancer therapeutics. This review briefly presents the physiological functions of PARPs, the pharmacokinetics, and pharmacodynamics, and the interaction profiles of FDA-approved PARP inhibitors. Comprehensively covered is the section on the drug design strategies employed by drug discovery enthusiasts for furnishing PARP inhibitors. The impact of structural variations in the template of designed scaffolds on enzymatic and cellular activity (structure-activity relationship studies) has been discussed. The insights gained through the biological evaluation such as profiling of physicochemical properties andin vitroADME properties, PK assessments, and high-dose pharmacology are covered.

Prudent tactics to sail the boat of PARP inhibitors as therapeutics for diverse malignancies.

INTRODUCTION: PARP inhibitors block the DNA-repairing mechanism of PARP and represent a promising class of anti-cancer therapy. The last decade has witnessed FDA approvals of several PARP inhibitors, with some undergoing advanced-stage clinical investigation. Medicinal chemists have invested much effort to expand the structure pool of PARP inhibitors. Issues associated with the use of PARP inhibitors that make their standing disconcerting in the pharmaceutical sector have been addressed via the design of new structural assemblages. AREA COVERED: In this review, the authors present a detailed account of the medicinal chemistry campaigns conducted in the recent past for the construction of PARP1/PARP2 inhibitors, PARP1 biased inhibitors, and PARP targeting bifunctional inhibitors as well as PARP targeting degraders (PROTACs). Limitations associated with FDA-approved PARP inhibitors and strategies to outwit the limitations are also discussed. EXPERT OPINION: The PARP inhibitory field has been rejuvenated with numerous tractable entries in the last decade. With numerous magic bullets in hand coupled with unfolded tactics to outwit the notoriety of cancer cells developing resistance toward PARP inhibitors, the dominance of PARP inhibitors as a sagacious option of targeted therapy is highly likely to be witnessed soon.

Beyond the vaccines: a glance at the small molecule and peptide-based anti-COVID19 arsenal.

Unprecedented efforts of the researchers have been witnessed in the recent past towards the development of vaccine platforms for the control of the COVID-19 pandemic. Albeit, vaccination stands as a practical strategy to prevent SARS-CoV-2 infection, supplementing the anti-COVID19 arsenal with therapeutic options such as small molecules/peptides and antibodies is being conceived as a prudent strategy to tackle the emerging SARS-CoV-2 variants. Noteworthy to mention that collective efforts from numerous teams have led to the generation of a voluminous library composed of chemically and mechanistically diverse small molecules as anti-COVID19 scaffolds. This review article presents an overview of medicinal chemistry campaigns and drug repurposing programs that culminated in the identification of a plethora of small molecule-based anti-COVID19 drugs mediating their antiviral effects through inhibition of proteases, S protein, RdRp, ACE2, TMPRSS2, cathepsin and other targets. In light of the evidence ascertaining the potential of small molecule drugs to approach conserved proteins required for the viral replication of all coronaviruses, accelerated FDA approvals are anticipated for small molecules for the treatment of COVID19 shortly. Though the recent attempts invested in this direction in pursuit of enrichment of the anti-COVID-19 armoury (chemical tools) are praiseworthy, some strategies need to be implemented to extract conclusive benefits of the recently reported small molecule viz. (i) detailed preclinical investigation of the generated anti-COVID19 scaffolds (ii) in-vitro profiling of the inhibitors against the emerging SARS-CoV-2 variants (iii) development of assays enabling rapid screening of the libraries of anti-COVID19 scaffold (iv) leveraging the applications of machine learning based predictive models to expedite the anti-COVID19 drug discovery campaign (v) design of antibody-drug conjugates.

Glioblastoma: Current Status, Emerging Targets, and Recent Advances.

Glioblastoma (GBM) is a highly malignant brain tumor characterized by a heterogeneous population of genetically unstable and highly infiltrative cells that are resistant to chemotherapy. Although substantial efforts have been invested in the field of anti-GBM drug discovery in the past decade, success has primarily been confined to the preclinical level, and clinical studies have often been hampered due to efficacy-, selectivity-, or physicochemical property-related issues. Thus, expansion of the list of molecular targets coupled with a pragmatic design of new small-molecule inhibitors with central nervous system (CNS)-penetrating ability is required to steer the wheels of anti-GBM drug discovery endeavors. This Perspective presents various aspects of drug discovery (challenges in GBM drug discovery and delivery, therapeutic targets, and agents under clinical investigation). The comprehensively covered sections include the recent medicinal chemistry campaigns embarked upon to validate the potential of numerous enzymes/proteins/receptors as therapeutic targets in GBM.

A Review on the Arylpiperazine Derivatives as Potential Therapeutics for the Treatment of Various Neurological Disorders.

Neurological disorders are disease conditions related to the neurons and central nervous system (CNS). Any structural, electrical, biochemical, and functional abnormalities in neurons can lead to various types of disorders, like Alzheimer's disease (AD), depression, Parkinson's disease (PD), epilepsy, stroke, etc. Currently available medicines are symptomatic and do not treat the disease state. Thus, novel CNS active agents with the potential to completely treat an illness are highly desired. A range of small organic molecules is being explored as potential drug candidates to cure different neurological disorders. In this context, arylpiperazinehas been found to be a versatile scaffold and indispensable pharmacophore in many CNS active agents. Several molecules with arylpiperazine nucleus have been developed as potent leads for the treatment of AD, PD, depression, and other disorders. The arylpiperazine nucleus can be optionally substituted at different chemical structures and offer flexibility for the synthesis of a large number of derivatives. In the current review article, we have explored the role of various arylpiperazine containing scaffolds against different neurological disorders, including AD, PD, and depression. The structure-activity relationship studies were conducted for recognizing potent lead compounds. This review article may provide important insights into the structural requirements for designing and synthesizing effective molecules as curative agents for different neurological disorders.

The Role of Epigenetic Mechanisms in Autoimmune, Neurodegenerative, Cardiovascular, and Imprinting Disorders.

Epigenetic mutations like aberrant DNA methylation, histone modifications, or RNA silencing are found in a number of human diseases. This review article discusses the epigenetic mechanisms involved in neurodegenerative disorders, cardiovascular disorders, auto-immune disorders and genomic imprinting disorders. In addition, emerging epigenetic therapeutic strategies for the treatment of such disorders are presented. Medicinal chemistry campaigns highlighting the efforts of the chemists invested towards the rational design of small molecule inhibitors have also been included. Pleasingly, several classes of epigenetic inhibitors, DNMT, HDAC, BET, HAT, and HMT inhibitors, along with RNA based therapies, have exhibited the potential to emerge as therapeutics in the longer run. It is quite hopeful that epigenetic modulator-based therapies will advance to clinical stage investigations by leaps and bounds.

A Review on Post-traumatic Stress Disorder (PTSD): Symptoms, Therapies and Recent Case Studies.

Post-traumatic stress disorder (PTSD), previously known as battle fatigue syndrome or shell shock, is a severe mental disturbance condition that is normally triggered by the experience of some frightening/scary events or trauma where a person undergoes some serious physical or mental harm or threatened. PTSD is a long-life effect of the continuous occurrence of traumatic conditions, leading to the production of feelings of helplessness, intense fear, and horror in the person. There are various examples of events that can cause PTSD, such as physical, mental, or sexual assault at home or working place by others, unexpected death of a loved one, an accidental event, war, or some kind of natural disaster. Treatment of PTSD includes the removal or reduction of these emotional feelings or symptoms with the aim to improve the daily life functioning of a person. Problems which are needed to be considered in case of PTSD like ongoing trauma, abusive or bad relationships. Various drugs which are used for the treatment of PTSD include selective serotonin reuptake inhibitors (SSRIs) (citalopram, fluvoxamine, fluoxetine, etc.); tricyclic antidepressants (amitriptyline and isocarboxazid); mood stabilizers (Divalproex and lamotrigine); atypical antipsychotics (aripiprazole and quetiapine), etc. In this review, we have covered the different risk factors, case studies related to various treatment options with different age group of peoples with PTSD and their effects on them. We have also covered the symptoms and associated disorders which can play a key role in the development of PTSD.

Multi-Target-Directed Ligands as an Effective Strategy for the Treatment of Alzheimer's Disease.

Alzheimer's disease (AD) is a complex neurological disorder and multiple pathological factors are believed to be involved in the genesis and progression of the disease. A number of hypothesis including Acetylcholinesterase, Monoamine oxidase, ß- Amyloid, Tau protein etc. have been proposed for the initiation and progression of the disease. At present, acetylcholine esterase inhibitors and memantine (NMDAR antagonist) are the only approved therapy for the symptomatic management of AD. Most of these single-target drugs have miserably failed in the treatment or halting the progression of the disease. Multi-factorial diseases like AD require complex treatment strategies that involve simultaneous modulation of a network of interacting targets. Since last few years, Multi-Target-Directed Ligands (MTDLs) strategy, drugs that can simultaneously hit multiple targets, is being explored as an effective therapeutic approach for the treatment of AD. In the current review article, the authors have briefly described various pathogenic pathways associated with the AD. Importance of Multi-Target-Directed Ligands and their design strategies in recently reported articles have been discussed in detail. Potent leads identified through various structure-activity relationship studies and their drug like characteristics are described. Recently developed promising compounds have been summarized in the article. Some of these MTDLs with balanced activity profile against different targets have the potential to be developed as drug candidates for the treatment of AD.

Role of Vitamins in Neurodegenerative Diseases: A Review.

BACKGROUND: Vitamins are the micronutrients required for boosting the immune system and managing any future infection. Vitamins are involved in neurogenesis, a defense mechanism working in neurons, metabolic reactions, neuronal survival, and neuronal transmission. Their deficiency leads to abnormal functions in the brain like oxidative stress, mitochondrial dysfunction, accumulation of proteins (synuclein, Aß plaques), neurodegeneration, and excitotoxicity. METHODS: In this review, we have compiled various reports collected from PubMed, Scholar Google, Research gate, and Science direct. The findings were evaluated, compiled, and represented in this manuscript. CONCLUSION: The deficiency of vitamins in the body causes various neurological disorders like Alzheimer's disease, Parkinson's disease, Huntington's disease, and depression. We have discussed the role of vitamins in neurological disorders and the normal human body. Depression is linked to a deficiency of vitamin-C and vitamin B. In the case of Alzheimer's disease, there is a lack of vitamin- B1, B12, and vitamin-A, which results in Aß-plaques. Similarly, in Parkinson's disease, vitamin- D deficiency leads to a decrease in the level of dopamine, and imbalance in vitamin D leads to accumulation of synuclein. In MS, vitamin-C and vitamin-D deficiency causes demyelination of neurons. In Huntington's disease, vitamin- C deficiency decreases the antioxidant level, enhances oxidative stress, and disrupts the glucose cycle. vitamin B5 deficiency in Huntington's disease disrupts the synthesis of acetylcholine and hormones in the brain.

Association of heart rate variability, blood pressure variability, and baroreflex sensitivity with gastric motility at rest and during cold pressor test.

AIM: To understand the mutual interaction of gastric motility and autonomic functions, the present study evaluated the association of heart rate variability (HRV), blood pressure variability (BPV), and baroreflex sensitivity (BRS) with gastric motility assessed by electrogastrography (EGG) at rest and during CPT and explored the effect of sympathetic activation by cold pressor test (CPT) on gastric motility. BACKGROUND: The autonomic nervous system has a significant influence on gastrointestinal motility. HRV is commonly employed to assess the functions of the autonomic nervous system. BPV and BRS are relatively newer techniques and give a more holistic picture of autonomic functions along with the short-term regulation of blood pressure (BP). METHODS: In fourteen young, healthy subjects, gastric motility was assessed by EGG. Beat-to-beat BP and lead II ECG were recorded to assess HRV, BPV, and BRS. BPV and BRS parameters were calculated for systolic, mean, and diastolic BP. Parameters of HRV and BPV were calculated for time and frequency domains. BRS was calculated by sequence and spectral methods. RESULTS: Significant increases in diastolic BP (p = <0.0001) and EGG frequency (p = 0.0229) were observed during CPT. Significant correlations were observed between EGG frequencies and many of the HRV, BPV, and BRS parameters. The correlation coefficient was found to be highest between total power of HRV and EGG frequencies during baseline (p = 0.0107, r = -0.6571) and during CPT (p = 0.0059, r = -0.6935). CONCLUSION: EGG frequency can be decreased by an acute increase in sympathetic activity induced by CPT. The novel findings are the significant correlations between many of the HRV, BPV, and BRS parameters and EGG frequency.

Steering the antitumor drug discovery campaign towards structurally diverse indolines.

Indoline framework is often perpended as a privileged heterocycle present in medicinally valuable compounds of natural and synthetic origin. This review article presents the rational approaches/strategies employed for the design of anticancer indolines along with the structure activity relationship and mechanistic insights revealed in the in-vitro and in-vivo assays. The chemist has always been fascinated towards the indoline ring for the construction of antitumor scaffolds owing to its versatility as evidenced by its existence in scaffolds inducing antiproliferative effects via diverse mechanisms. To the delight of medicinal chemist, the applicability of indoline has also been expanded towards the design of dual inhibitors (multitargeting anticancer agents) as well as PROTACS. Overall, it can be concluded that indoline moiety is a magic bullet and the scaffolds containing this ring are foraying towards detailed preclinical and clinical stage investigations by leaps and bounds.

Targeting Cancer Stem Cells Pathways for the Effective Treatment of Cancer.

Resistance to chemotherapy and relapse are major hurdles for the effective treatment of cancer. Major reason for this is a small sub population of cancer stem cells (CSCs) and its microenvironment. CSCs are critical driving force for several types of cancer, such as gastric, colon, breast and many more. Hence, for the complete eradication of cancer, it is necessary to develop therapeutic approaches that can specifically target CSCs. Chemical agents that target different proteins involved in CSC signaling pathways, either as single agent or simultaneously targeting two or more proteins have generated promising pre-clinical and clinical results. In the current review article, we have discussed various targets and cellular pathways that can be explored for the effective and complete eradication of CSCs. Some latest developments in the field of design, synthesis and screening of ligands to target cancer stem cells have been summarized in the current review article.