PROTAC'ing oncoproteins: targeted protein degradation for cancer therapy.

Molecularly targeted cancer therapies substantially improve patient outcomes, although the durability of their effectiveness can be limited. Resistance to these therapies is often related to adaptive changes in the target oncoprotein which reduce binding affinity. The arsenal of targeted cancer therapies, moreover, lacks coverage of several notorious oncoproteins with challenging features for inhibitor development. Degraders are a relatively new therapeutic modality which deplete the target protein by hijacking the cellular protein destruction machinery. Degraders offer several advantages for cancer therapy including resiliency to acquired mutations in the target protein, enhanced selectivity, lower dosing requirements, and the potential to abrogate oncogenic transcription factors and scaffolding proteins. Herein, we review the development of proteolysis targeting chimeras (PROTACs) for selected cancer therapy targets and their reported biological activities. The medicinal chemistry of PROTAC design has been a challenging area of active research, but the recent advances in the field will usher in an era of rational degrader design.

Disruption of retinal inflammation and the development of diabetic retinopathy in mice by a CD40-derived peptide or mutation of CD40 in Müller cells.

AIMS/HYPOTHESIS: CD40 expressed in Müller cells is a central driver of diabetic retinopathy. CD40 causes phospholipase Cγ1 (PLCγ1)-dependent ATP release in Müller cells followed by purinergic receptor (P2X7)-dependent production of proinflammatory cytokines in myeloid cells. In the diabetic retina, CD40 and P2X7 upregulate a broad range of inflammatory molecules that promote development of diabetic retinopathy. The molecular event downstream of CD40 that activates the PLCγ1-ATP-P2X7-proinflammatory cytokine cascade and promotes development of diabetic retinopathy is unknown. We hypothesise that disruption of the CD40-driven molecular events that trigger this cascade prevents/treats diabetic retinopathy in mice. METHODS: B6 and transgenic mice with Müller cell-restricted expression of wild-type (WT) CD40 or CD40 with mutations in TNF receptor-associated factor (TRAF) binding sites were made diabetic using streptozotocin. Leucostasis was assessed using FITC-conjugated concanavalin A. Histopathology was examined in the retinal vasculature. Expression of inflammatory molecules and phospho-Tyr783 PLCγ1 (p-PLCγ1) were assessed using real-time PCR, immunoblot and/or immunohistochemistry. Release of ATP and cytokines were measured by ATP bioluminescence and ELISA, respectively. RESULTS: Human Müller cells with CD40 ΔT2,3 (lacks TRAF2,3 binding sites) were unable to phosphorylate PLCγ1 and release ATP in response to CD40 ligation, and could not induce TNF-α/IL-1ß secretion in bystander myeloid cells. CD40-TRAF signalling acted via Src to induce PLCγ1 phosphorylation. Diabetic mice in which WT CD40 in Müller cells was replaced by CD40 ΔT2,3 failed to exhibit phosphorylation of PLCγ1 in these cells and upregulate P2X7 and TNF-α in microglia/macrophages. P2x7 (also known as P2rx7), Tnf-α (also known as Tnf), Il-1ß (also known as Il1b), Nos2, Icam-1 (also known as Icam1) and Ccl2 mRNA were not increased in these mice and the mice did not develop retinal leucostasis and capillary degeneration. Diabetic B6 mice treated intravitreally with a cell-permeable peptide that disrupts CD40-TRAF2,3 signalling did not exhibit either upregulation of P2X7 and inflammatory molecules in the retina or leucostasis. CONCLUSIONS/INTERPRETATION: CD40-TRAF2,3 signalling activated the CD40-PLCγ1-ATP-P2X7-proinflammatory cytokine pathway. Src functioned as a link between CD40-TRAF2,3 and PLCγ1. Replacing WT CD40 with CD40 ΔT2,3 impaired activation of PLCγ1 in Müller cells, upregulation of P2X7 in microglia/macrophages, upregulation of a broad range of inflammatory molecules in the diabetic retina and the development of diabetic retinopathy. Administration of a peptide that disrupts CD40-TRAF2,3 signalling reduced retinal expression of inflammatory molecules and reduced leucostasis in diabetic mice, supporting the therapeutic potential of pharmacological inhibition of CD40-TRAF2,3 in diabetic retinopathy.

Design, synthesis and anticancer activity of 2-arylimidazo[1,2-a]pyridinyl-3-amines.

A series of imido-heterocycle compounds were designed, synthesized, characterized, and evaluated for the anticancer potential using breast (MCF-7 and MDA-MB-231), pancreatic (PANC-1), and colon (HCT-116 and HT-29) cancer cell lines and normal cells, while normal cells showed no toxicity. Among the screened compounds, 4h exhibited the best anticancer potential with IC50 values ranging from 1 to 5.5 µM. Compound 4h caused G2/M phase arrest and apoptosis in all the cell lines except MDA-MB-231 mammosphere formation was inhibited. In-vitro enzyme assay showed selective topoisomerase IIα inhibition by compound 4h, leading to DNA damage as observed by fluorescent staining. Cell signalling studies showed decreased expression of cell cycle promoting related proteins while apoptotic proteins were upregulated. Interestingly MDA-MB-231 cells showed only cytostatic effects upon treatment with compound 4h due to defective p53 status. Toxicity study using overexpression of dominant-negative mutant p53 in MCF-7 cells (which have wild type functional p53) showed that anticancer potential of compound 4h is positively correlated with p53 expression.

Synthesis of 1,4-dihydropyrazolo[4,3-b]indoles via intramolecular C(sp2)-N bond formation involving nitrene insertion, DFT study and their anticancer assessment.

We herein report a new synthetic route for a series of unreported 1,4-dihydropyrazolo[4,3-b]indoles (6-8) via deoxygenation of o-nitrophenyl-substituted N-aryl pyrazoles and subsequent intramolecular (sp2)-N bond formation under microwave irradiation expedite modified Cadogan condition. This method allows access to NH-free as well as N-substituted fused indoles. DFT study and controlled experiments highlighted the role of nitrene insertion as one of the plausible reaction mechanisms. Furthermore, the target compounds exhibited cytotoxicity at low micromolar concentration against lung (A549), colon (HCT-116), and breast (MDA-MB-231, and MCF-7) cancer cell lines, induced the ROS generation and altered the mitochondrial membrane potential of highly aggressive MDA-MB-231 cells. Further investigations revealed that these compounds were selective Topo I (6h) or Topo II (7a, 7b) inhibitors.

Design and Synthesis of Non-Covalent Imidazo[1,2-a]quinoxaline-Based Inhibitors of EGFR and Their Anti-Cancer Assessment.

A series of 30 non-covalent imidazo[1,2-a]quinoxaline-based inhibitors of epidermal growth factor receptor (EGFR) were designed and synthesized. EGFR inhibitory assessment (against wild type) data of compounds revealed 6b, 7h, 7j, 9a and 9c as potent EGFRWT inhibitors with IC50 values of 211.22, 222.21, 193.18, 223.32 and 221.53 nM, respectively, which were comparable to erlotinib (221.03 nM), a positive control. Furthermore, compounds exhibited excellent antiproliferative activity when tested against cancer cell lines harboring EGFRWT; A549, a non-small cell lung cancer (NSCLC), HCT-116 (colon), MDA-MB-231 (breast) and gefitinib-resistant NSCLC cell line H1975 harboring EGFRL858R/T790M. In particular, compound 6b demonstrated significant inhibitory potential against gefitinib-resistant H1975 cells (IC50 = 3.65 µM) as compared to gefitinib (IC50 > 20 µM). Moreover, molecular docking disclosed the binding mode of the 6b to the domain of EGFR (wild type and mutant type), indicating the basis of inhibition. Furthermore, its effects on redox modulation, mitochondrial membrane potential, cell cycle analysis and cell death mode in A549 lung cancer cells were also reported.

Reactions of HDDA Benzynes with C,N-Diarylimines (ArCH=NAr').

o-Benzynes can be utilized to construct heterocyclic motifs using various nucleophilic and cycloaddition trapping reactions. Acridines have been synthesized by capture of C,N-diarylimines with benzynes generated by classical methods (i.e., from ortho-elimination of precursor arene compounds), although in poor yields. We report here that these imines can be trapped by benzynes generated by the hexadehydro-Diels-Alder (HDDA) reaction in an efficient manner to produce 1,4-dihydroacridine products. These dihydroacridines were subsequently aromatized using MnO2 to provide structurally complex acridines.

Neuro-Chikungunya: Acute Transverse Myelopathy Associated with Chikungunya Virus Infection.

Chikungunya is an arboviral infection caused by Chikungunya virus, an RNA virus from Togaviridae family.1 The disease manifests as fever, rash and characteristically, with arthralgia.1 Chikungunya is strongly believed to have neurotropism but has not been well studied like other neurotropic arboviruses.2 Encephalitis appears to represent the most common clinical manifestation6 and occurs either simultaneously or within few days of onset of systemic symptoms, during the period of viremia. A delay of more than two weeks has been reported with other complications like myelitis, Guillian Barre syndrome and optic neuritis. This case describes the clinical, serological, neuroimaging and CSF findings of Chikungunya induced acute transverse myelitis in a 13 years old male patient who responded to steroid treatment. It is a relatively unknown and very rare complication of Chikungunya virus infection during outbreak of Chikungunya infection in September 2016.

Double heteroannulation of S,N-acetals: a facile access to quinolone derivatives.

A rapid construction of quinolone fused heterocycles from single S,N-acetal precursors via double heteroannulation is described. The base, radical and metal-mediated reactions can control the C-N, C-S and C-O bond formations of the S,N-acetal with high chemoselectivity.

Contralateral reversed distal femoral locking plate for fixation of subtrochanteric femoral fractures.

PURPOSE: Subtrochanteric fractures of the femur are being managed successfully with various intramedullary and extramedulary implants with reasonable success. However, these implants require precise placement under image intensifier guidance, which exposes the surgeon to substantial amount of radiation. It also restricts the management of these fractures at peripheral centers where facility of image intensifiers is not available. Keeping this in mind we designed this study to identify if contralateral reversed distal femoral locking plate can be used successfully without the use of image intensifier. METHODS: Twenty-four consecutive patients (18 men and 6 women) with a mean age of 28 years (range 19-47 years) suffering subtrochanteric fractures of the femur underwent open reduction and internal fixation with reversed contralateral distal femoral locking plate. The outcome was assessed at the mean follow-up period of 3.2 years (range 2-4.6 years) using the Harris hip score. RESULTS: Twenty-one fractures united with the primary procedure, with a mean time of consolidation being 11 weeks (range, 9-16 weeks). One patient developed superficial suture line infection, which resolved with oral antibiotics. Another patient had a fall 3 weeks after surgery and broke the plate. Repeat surgery with reversed distal femoral locking compression plate was performed along with bone grafting and the fracture united. Two cases had nonunion, which went in for union after bone grafting. The mean Harris hip score at the time of final follow-up was 90.63 (range 82-97). CONCLUSION: The reversed contralateral distal femoral plate is a biomechanically sound implant, which when used for fixation of the subtrochanteric fractures with minimal soft tissue stripping shows results comparable to those achieved by using other extramedullary implants as well as intramedullary devices. The added advantage of this implant is its usability in the absence of an image intensifier.

Polysomnographic Assessment on Osahs Outcomes in Patients with Nasal Obstruction Undergoing Septoplasty with Partial Inferior Turbinectomy.

The relationship between nasal obstruction and obstructive sleep apnea has raised interest among otolaryngologists since years. There are studies that suggest that surgical correction of nasal obstruction improves sleep quality and reduces symptoms of sleep apnea. This lead to our study to understand the effect of nasal surgery on obstructive sleep apnea hypopnea syndrome (OSAHS). AIM: To assess the effect of nasal surgery in improvement in Obstructive Sleep Apnoea Hypopnoea Syndrome in patients with nasal obstruction by Polysomnography (PSG). MATERIAL AND METHODS: This study included 30 patients with nasal obstruction who underwent septoplasty and/or turbinate reduction procedure with pre and post operative assessment of respiratory distress index (RDI) including apnoea hypopnoea index (AHI), obstructive apnoea index (OAI), Snoring Index (SI) using polysomnography (PSG). RESULT: Nasal correction surgery showed statistically significant improvement (p-value < 0.001) in RDI from 13.66 to 6.66, OAI from 6.34 to 3.18 and Snoring Index from 161.77 to 62.23 as assessed by polysomnography. There was statistically significant improvement in minimal saturation levels (during sleep) and positional sleep apnoea. CONCLUSION: Isolated nasal surgery like septoplasty and/or turbinate reduction improved sleep parameters and alleviated OSA symptoms in patients with static nasal obstruction and obstructive sleep apnoea/hypopnoea syndrome. However, patients with multilevel or dynamic airway obstruction may need further intervention.

Current insights and molecular docking studies of HIV-1 reverse transcriptase inhibitors.

Human immunodeficiency virus (HIV) causes acquired immunodeficiency syndrome (AIDS), a lethal disease that is prevalent worldwide. According to the Joint United Nations Programme on HIV/AIDS (UNAIDS) data, 38.4 million people worldwide were living with HIV in 2021. Viral reverse transcriptase (RT) is an excellent target for drug intervention. Nucleoside reverse transcriptase inhibitors (NRTIs) were the first class of approved antiretroviral drugs. Later, a new type of non-nucleoside reverse transcriptase inhibitors (NNRTIs) were approved as anti-HIV drugs. Zidovudine, didanosine, and stavudine are FDA-approved NRTIs, while nevirapine, efavirenz, and delavirdine are FDA-approved NNRTIs. Several agents are in clinical trials, including apricitabine, racivir, elvucitabine, doravirine, dapivirine, and elsulfavirine. This review addresses HIV-1 structure, replication cycle, reverse transcription, and HIV drug targets. This study focuses on NRTIs and NNRTIs, their binding sites, mechanisms of action, FDA-approved drugs and drugs in clinical trials, their resistance and adverse effects, their molecular docking studies, and highly active antiretroviral therapy (HAART).

Potential role of herbal nanoformulations for skin disorders: a review.

Aim: In the recent advanced study, the popularity of herbal nano-formulation has gained around the whole world. As we know the reason behind it is that herbal products have comparatively lesser side effects than other synthetic products. Significance: These natural plant extracts have wide medicinal importance as they increase the overall bioavailability of products toward tissues. Key findings: This review provides the use of different herbal nano-formulations, their safety considerations, and the challenges being faced. It also highlights the various Clinical Trials and Patents that are published for skin disorders. Conclusion: The present review describes how the rise of herbal products has made wider interest in transdermal formulations and improve the overall productivity by preventing various skin disorders.

A Short Appraisal of Biomimetic Hydrogels to Improve Penetration of Poorly Permeable Drugs.

Effective drug delivery to target sites is critical for achieving desired therapeutic outcomes. However, the poor permeability of certain drugs poses significant challenges in achieving adequate drug concentrations at the desired locations. Biomimetic hydrogels have emerged as a promising approach to enhance the penetration of poorly permeable drugs. These hydrogels, designed to mimic natural biological systems, offer unique properties and functionalities that enable improved drug permeation. In this review, we provide a comprehensive appraisal of the role of biomimetic hydrogels in enhancing drug penetration. We discuss the design principles, properties, and mechanisms by which these hydrogels facilitate drug permeation. Specifically, we explore the applications and benefits of biomimetic hydrogels in controlled drug release, mimicking extracellular matrix microenvironments, promoting cell-mimetic interactions, and enabling targeted drug delivery. Through an examination of key studies and advancements, we highlight the potential of biomimetic hydrogels in enhancing drug penetration and their implications for therapeutic interventions. This review contributes to a deeper understanding of biomimetic hydrogels as a promising strategy for overcoming drug penetration challenges and advancing drug delivery systems, ultimately leading to improved therapeutic efficacy.

The design of PINO-like hydrogen-atom-transfer catalysts.

Phthalimide-N-oxyl (PINO) is a valuable hydrogen-atom-transfer (HAT) catalyst for selective C-H functionalization. To advance and optimize PINO-catalysed HAT reactions, researchers have been focused on modifying the phthalimide core structure. Despite much effort and some notable advances, the modifications to date have centred on optimization of a single parameter of the catalyst, such as reactivity, solubility or stability. Unfortunately, the optimization with respect to one parameter is often associated with a worsening of the others. The derivation of a single catalyst structure with optimal performance across multiple parameters has therefore remained elusive. Here we present an analysis of the structure-activity relationships of PINO and its derivatives as HAT catalysts, which we hope will stimulate further development of PINO-catalysed HAT reactions and, ultimately, lead to much improved catalysts for real-world applications.

Onion ring sign on spectral domain optical coherence tomography in diabetic macular edema: Its evolution and outcomes.

PURPOSE: To report evolution and outcomes of hyperreflective crystalline deposit (HCD) on optical coherence tomography (OCT) in diabetic maculopathy (DM). METHODS: Patients with DM showing HCD on OCT for the first time between June 2017 and May 2021 were included in the study. Demographic, ophthalmic and OCT features were documented and analysed. Factors leading to the development of HCD and its effect on the functional outcome were analysed and described in this study. RESULTS: Sixty cases of HCD were identified in 45 (males -33; females - 12) patients for the first-time during the defined study period. Mean age of the eligible patients was 61.53 ± 8.19 years. Average duration of diabetes was 13.82 ± 7.38 years. Mean visual acuity of these patients was 0.902 ± 0.438 logMAR units (Snellen equivalent = 20/160). Patients with HCD showed subretinal hard exudates, were on anti-cholesterol medications (n = 36, 80%) and showed reduced visual acuity (20/160) if the HCD involved the fovea. The median time taken for the development of HCD was 28 months. Mean follow-up duration of the study was 26.19 ± 27.98 months. Persistence of HCD in all cases (n = 42, 100%) was noted at the last follow-up visit. CONCLUSION: Horizontal, single or multi-layered HCDs on OCT in DM represent intraretinal or subretinal cholesterol crystal precipitates evolving from the hard exudates identical to the "onion ring sign" seen in neovascular AMD. HCDs or CCs depict deranged lipid metabolism, chronic vascular leakage and can lead to substantial visual impairment if the fovea gets involved.

Choroidal changes in posterior microphthalmos.

PURPOSE: To describe the choroidal variations in posterior microphthalmos (PM). METHODS: In this observational case series, four eyes of two patients diagnosed as PM based on the characteristic clinical features were included. Multimodal retinal imaging with clinical fundus documentation using ultrawide field fundus camera, optical coherence tomography (OCT) and indocyanine green angiography (ICGA) was done for these cases. RESULTS: Multimodal imaging of these cases confirmed the variations in the choroid in PM cases. In both cases, on OCT, the retina and choroid were thick. retinal papillomacular fold (RPMF) was noted in all four eyes. On ICGA, the dye transit time from the arm to choroid and retina were within normal limits. Choroidal vasculature in the far retinal periphery was reduced and was noted as hypocyanescent areas anterior to the equator while the density of choroidal vessels was significantly more posterior to the equator. Vortex veins were not visualised in both cases. CONCLUSION: Choroidal structure and vessels undergo alterations in PM. Further validation of these findings is required in a larger cohort of PM cases.

ALK and ERBB2 Protein Inhibition is Involved in the Prevention of Lung Cancer Development by Vincamine.

BACKGROUND: According to the WHO report of 2022, 2.21 million new cases and 1.80 million deaths were reported for lung cancer in the year 2020. Therefore, there is an urgent need to explore novel, safe, and effective therapeutic interventions for lung cancer. OBJECTIVE: To find the potential targets of vincamine using a network pharmacology approach and docking studies and to evaluate the anti-cancer effect of vincamine on A549 cell line. METHODS: Hence, in the present study, we explored the anti-cancer potential of vincamine by using network pharmacology, molecular docking, and in vitro approaches. Network pharmacology demonstrated that the most common targets of vincamine are G-protein coupled receptors, cytosolic proteins, and enzymes. Among these targets, two targets, ALK and ERBB2 protein, were common between vincamine and non-small cell lung cancer. RESULTS: We discovered a link between these two targets and their companion proteins, as well as cancer-related pathways. In addition, a docking investigation between the ligand for vincamine and two targeted genes revealed a strong affinity toward these targeted proteins. Further, the in vitro study demonstrated that vincamine treatment for 72 h led to dosedependent (0-500 µM) cytotoxicity on the A549 lung cancer cell line with an IC50 value of 291.7 µΜ. The wound-healing assay showed that vincamine treatment (150 and 300 µM) significantly inhibited cell migration and invasion. Interestingly, acridine orange/ethidium bromide dual staining demonstrated that vincamine treatment induces apoptosis in A549 cells. Additionally, the dichloro-dihydro-fluorescein diacetate (DCFH-DA) assay showed an increased level of reactive oxygen species (ROS) after the vincamine treatment, indicating ROS-mediated apoptosis in A549 cells. CONCLUSION: Altogether, based on our findings, we hypothesize that vincamine-induced apoptosis of lung cancer cells via ALK and ERBB2 protein modulation may be an attractive futuristic strategy for managing lung cancer in combination with chemotherapeutic agents to obtain synergistic effects with reduced side effects.

Targeting the Epidermal Growth Factor Receptor with Molecular Degraders: State-of-the-Art and Future Opportunities.

Epidermal growth factor receptor (EGFR) is an oncogenic drug target and plays a critical role in several cellular functions including cancer cell growth, survival, proliferation, differentiation, and motility. Several small-molecule tyrosine kinase inhibitors (TKIs) and monoclonal antibodies (mAbs) have been approved for targeting intracellular and extracellular domains of EGFR, respectively. However, cancer heterogeneity, mutations in the catalytic domain of EGFR, and persistent drug resistance limited their use. Different novel modalities are gaining a position in the limelight of anti-EGFR therapeutics to overcome such limitations. The current perspective reflects upon newer modalities, importantly the molecular degraders such as PROTACs, LYTACs, AUTECs, and ATTECs, etc., beginning with a snapshot of traditional and existing anti-EGFR therapies including small molecule inhibitors, mAbs, and antibody drug conjugates (ADCs). Further, a special emphasis has been made on the design, synthesis, successful applications, state-of-the-art, and emerging future opportunities of each discussed modality.

TMPRSS2 Inhibitor Discovery Facilitated through an In Silico and Biochemical Screening Platform.

The COVID-19 pandemic has highlighted the need for new antiviral approaches because many of the currently approved drugs have proven ineffective against mitigating SARS-CoV-2 infections. The host transmembrane serine protease TMPRSS2 is a promising antiviral target because it plays a role in priming the spike protein before viral entry occurs for the most virulent variants. Further, TMPRSS2 has no established physiological role, thereby increasing its attractiveness as a target for antiviral agents. Here, we utilize virtual screening to curate large libraries into a focused collection of potential inhibitors. Optimization of a recombinant expression and purification protocol for the TMPRSS2 peptidase domain facilitates subsequent biochemical screening and characterization of selected compounds from the curated collection in a kinetic assay. In doing so, we identify new noncovalent TMPRSS2 inhibitors that block SARS-CoV-2 infectivity in a cellular model. One such inhibitor, debrisoquine, has high ligand efficiency, and an initial structure-activity relationship study demonstrates that debrisoquine is a tractable hit compound for TMPRSS2.

Trapping Reactions of Benzynes Initiated by Intramolecular Nucleophilic Addition of a Carbonyl Oxygen to the Electrophilic Aryne.

We describe here reactions in which a carbonyl oxygen atom initiates cascade reactions by nucleophilic attack on a covalently attached benzyne. The benzynes are produced by thermal cyclization of triynes via hexadehydro-Diels-Alder reaction. The initially produced oxocarbenium/aryl carbanionic zwitterion is protonated in situ by an external protic nucleophile (NuH) of appropriate acidity. The resulting ion pair (oxocarbenium+/Nu-) collapses through several different mechanistic manifolds, adding to the diversity of structural classes that can be generated.