Medicinal Chemistry Approaches Research Articles

Screening and design of PARP12 inhibitors from traditional Chinese medicine small molecules using computational modeling and simulation

The poly (ADP-ribose) polymerase (PARP) family of enzymes plays a pivotal role in orchestrating a multitude of cellular processes, including DNA repair mechanisms, transcriptional regulation, and modulation of immune responses. Within this family, PARP12 emerges as a noteworthy candidate for targeted cancer therapeutics. Consequently, this investigation endeavors to screen and design potential PARP12 inhibitors derived from traditional Chinese medicinal compounds by employing sophisticated molecular modeling and computational medicinal chemistry approaches. The compound RBN2397 is utilized as a benchmark, and the binding efficacies of the newly identified small molecules are assessed against a spectrum of criteria, encompassing molecular interactions, binding free energy, and extensive post-simulation analyses. The outcomes demonstrated that the identified small molecules, specifically tcm8650 and its derivative XC-1, possess remarkable binding affinities and exhibit reduced binding free energies compared to RBN2397. The molecular docking and interaction profiles of these compounds were also comprehensively scrutinized. Moreover, ADMET profiling meticulously evaluated the pharmacokinetic profiles and physicochemical characteristics of these promising molecules and their projected human physiological impact. These computational studies indicated their potential therapeutic applicability and predicted acceptable safety profile, advocating their further exploration as viable candidates in cancer treatment.

Quantifying and mitigating motor phenotypes induced by antisense oligonucleotides in the central nervous system

Antisense oligonucleotides (ASOs) are emerging as a promising class of therapeutics for neurological diseases. When injected directly into cerebrospinal fluid, ASOs distribute broadly across brain regions and exert long-lasting therapeutic effects. However, many phosphorothioate (PS)-modified gapmer ASOs show transient motor phenotypes when injected into the cerebrospinal fluid, ranging from reduced motor activity to ataxia or acute seizure-like phenotypes. Using a behavioral scoring assay customized to reflect the timing and nature of these effects, we show that both sugar and phosphate modifications influence acute motor phenotypes. Among sugar analogues, DNA induces the strongest motor phenotypes while 2'-substituted RNA modifications improve the tolerability of PS-ASOs. Reducing the PS content of gapmer ASOs, which contain a stretch of PS-DNA, improves their toxicity profile, but in some cases also reduces efficacy or duration of effect. We show that this acute toxicity is not mediated by major nucleic acid sensing immune pathways. Formulating ASOs with divalent ions before injection and avoiding phosphate-based buffers modestly improved tolerability through mechanisms at least partially distinct from reduced PS content. Overall, our work identifies and quantifies an understudied aspect of oligonucleotide toxicology in the CNS, explores its mechanism, and presents platform-level medicinal chemistry and formulation approaches that improve tolerability of this class of compounds.

In-Silico ADMET Prediction, Structure-Based Drug Design and Molecular Docking Studies of Quinazoline Derivatives as Novel EGFR Inhibitors

This Present research provides valuable insights and implications for the development of quinazoline derivatives as novel EGFR inhibitors. The in-silico ADMET predictions indicate that the quinazoline derivatives possess promising drug-like properties, suggesting their potential for further development as oral drugs. The low risk of toxicity and favorable metabolic and excretion profiles enhance their suitability for therapeutic applications Molecular docking studies revealed strong binding interactions between the quinazoline derivatives and the EGFR kinase domain. These interactions suggest that these compound shave the potential to effectively inhibit EGFR activity, making them promising candidates for anti- cancer drug development to progress from in-silico findings to clinical applications, further research is essential. Future work should encompass in vitro and in vivo experiments to validate the inhibitory potential of these compounds against EGFR. Additionally, pharmacokinetic studies are warranted to confirm their ADMET properties. Structural optimization through medicinal chemistry approaches may further enhance their binding affinities and specificity for EGFR. It represents a pivotal step in the exploration of quinazoline derivatives as novel EGFR inhibitors. The combined efforts in ADMET prediction, structure-based drug design, and molecular docking have provided a strong foundation for the development of innovative anti-cancer therapies. The potential of these compounds to target EGFR, a crucial player in various cancers, holds great promise for improving the treatment options available to patients and advancing the field of oncology.

A General and Scalable Method toward Enantioenriched C2-Substituted Azetidines Using Chiral tert-Butanesulfinamides.

Diverse ranges of chiral nitrogen-containing heterocycles serve as a molecular toolbox for modulating a wide array of biological processes, but enantioenriched production of smaller chiral heterocycles is a bottleneck. There is a lack of general approaches for the stereoselective preparation of chiral 4-membered monocyclic C2-substituted azetidines, where many routes to different substitution types are possible, but no simple and common approach exists. To bridge this gap, inexpensive and widely available chiral tert-butanesulfinamides are harnessed for chiral induction with 1,3-bis-electrophilic 3-chloropropanal, providing a three-step approach to C2-substituted azetidines with aryl, vinyl, allyl, branched alkyl, and linear alkyl substituents. Eleven azetidine products are produced, and the approach is shown to be effective on a gram-scale with a single purification of the protected azetidine product in 44% yield over three steps in an 85:15 diastereomeric ratio. In most cases, the diastereomers are separable using normal phase chromatography, often resulting in previously elusive enantiopure azetidine products. Protected azetidines were shown to undergo rapid and efficient sulfinamide cleavage, producing an azetidine hydrochloride salt that was subjected to derivatization reactions, highlighting the method's applicability to medicinal chemistry approaches.

Targeting HSP90 for Cancer Therapy: Current Progress and Emerging Prospects.

Heat shock protein 90 (HSP90), a highly conserved member of the heat shock protein family, regulates various proteins and signaling pathways involved in cancer, making it a promising target for cancer therapy. Traditional HSP90 inhibitors have demonstrated significant antitumor potential in preclinical trials, with over 20 compounds advancing to clinical trials and showing promising results. However, the limited clinical efficacy and shared toxicity of these inhibitors restrict their further clinical use. Encouragingly, developing novel inhibitors using conventional medicinal chemistry approaches─such as selective inhibitors, dual inhibitors, protein-protein interaction inhibitors, and proteolysis-targeting chimeras─is expected to address these challenges. Notably, the selective inhibitor TAS-116 has already been successfully marketed. In this Perspective, we summarize the structure, biological functions, and roles of HSP90 in cancer, analyze the clinical status of HSP90 inhibitors, and highlight the latest advancements in novel strategies, offering insights into their future development.

State-of-the-Art Nrf2 Inhibitors: Therapeutic Opportunities in Non-Cancer Diseases.

Nuclear factor erythroid 2-related factor (Nrf2) is a cytoprotective transcription factor that induces the transcription of genes responsible for the cell's response to oxidative stress. While Nrf2 activation has led to the development of clinically relevant therapeutics, the oncogenic role of Nrf2 in the proliferation of cancer cells has underscored the complex nature of Nrf2 and the necessity for the development of Nrf2 inhibitors. Although the application of Nrf2 inhibitors appears limited as anticancer agents, recent studies have begun to pinpoint the impairment of autophagy in diseases as a cellular marker that shifts Nrf2 from a protective to a deleterious state. Therefore, the cytoplasmic accumulation of Nrf2 can lead to the accumulation of lipid hydroperoxides and, ultimately, to ferroptosis. However, some studies aimed at elucidating the role of Nrf2 in non-cancer diseases have yielded conflicting results, attributed to differences in approaches used to inhibit or activate Nrf2, as well as variations in in vitro and/or in vivo disease models. Overall, these results highlight the necessity for a deeper evaluation of Nrf2's role in diseases, especially chronic diseases. In this review, we discuss diseases where Nrf2 inhibition holds potential for beneficial therapeutic effects and summarize recently reported Nrf2 inhibitors exploiting medicinal chemistry approaches suitable for targeting transcription factors like Nrf2.

N-Methyl-D-Aspartate (NMDA) Receptor Antagonists and their Pharmacological Implication: A Medicinal Chemistry-oriented Perspective Outline.

N-methyl-D-aspartate (NMDA) receptors, i.e., inotropic glutamate receptors, are important in synaptic plasticity, brain growth, memory, and learning. The activation of NMDA is done by neurotransmitter glutamate and co-agonist (glycine or D-serine) binding. However, the over-activation of NMDA elevates the intracellular calcium influx, which causes various neurological diseases and disorders. Therefore, to prevent excitotoxicity and neuronal death, inhibition of NMDA must be done using its antagonist. This review delineates the structure of subunits of NMDA and the conformational changes induced after the binding of agonists (glycine and D-serine) and antagonists (ifenprodil, etc.). Additionally, reported NMDA antagonists from different sources, such as synthetic, semisynthetic, and natural resources, are explained by their mechanism of action and pharmacological role. The comprehensive report also addresses the chemical spacing of NMDA inhibitors and in-vivo and in-vitro models to test NMDA antagonists. Since the Blood-Brain Barrier (BBB) is the primary membrane that prevents the penetration of a wide variety of drug molecules, we also elaborate on the medicinal chemistry approach to improve the effectiveness of their antagonists.

Tirbanibulin (KX2-391) analog KX2-361 inhibits botulinum neurotoxin serotype A mediated SNAP-25 cleavage in pre- and post-intoxication models in cells.

Botulinum neurotoxins (BoNT) inhibit neuroexocytosis, leading to the potentially lethal disease botulism. BoNTserotype A is responsible for most human botulism cases, and there are no approved therapeutics to treat already intoxicated patients. A growing body of research has demonstrated that BoNT/A can escape into the central nervous system, and therefore, identification of BoNT/A inhibitors that can penetrate BBB and neutralize the toxin within intoxicated neurons would be important. We previously identified an FDA-approved, orally bioavailable compound, KX2-391 (Tirbanibulin)that inhibits BoNT/A in motor neuron assays. Recently, a structural analog of KX2-391, KX2-361, has been shown to exhibit good oral bioavailability and cross BBB with high efficiency in mouse experiments. Therefore, in this work, we evaluated the inhibitory effects of KX2-361 against BoNT/A. Toward this goal, we first evaluated the compound for its effects on cell viability in PC12 cells, via MTT assay, and in mouse embryonic stem cell (mESC)-derived motor neurons, with imaging-based assays. Following, we tested KX2-361 in mESC-derived motor neurons intoxicated with BoNT/A holotoxin, and the compound exhibited activity against the toxin in both pre- and post-intoxication conditions. Excitingly, KX2-361 also inhibited BoNT/A enzymatic component (light chain; LC) in PC12 cells transfected with BoNT/A LC. Furthermore, our molecular docking analyses suggested that KX2-361 can directly bind to BoNT/A LC. Medicinal chemistry approaches to develop structural analogs of KX2-361 to increase its efficacy against BoNT/A may provide a critical lead compound with BBB penetration capacity for drug development efforts against BoNT/A intoxication.

Biochar from malt residue: Toward a circular economy for sustainable fluoroquinolone removal in aqueous systems

Malt bagasse holds potential as a high-value material, contributing to a circular economy. Biochars were synthesized via pyrolysis (PC-500) and hydrothermal carbonization (HC-150), with one-pot activation using phosphoric acid. Additionally, PC-500 activated with H3PO4 was synthesized for comparison. Various analytical methods were used to characterize the materials. The PC-500 and PCA-500 samples exhibited higher degrees of carbonization, whereas the HC-150 sample retained its functional groups more effectively. Biochars showed higher porosity than biomass, with microspheres present in HC-150. Evaluations were conducted on the removal of fluoroquinolones from water using biochars. Maximum removal efficiency was obtained at pH 8, favoring neutral fluoroquinolone species with a Brønsted acid-base nature. The experimental outcomes were further rationalized by the computational calculation of the physicochemical properties of the adsorbates, in analogy with the structural activity relationship approach in medicinal chemistry. The pseudo-second-order kinetic model proved to be the most suitable for fitting the experimental data, while the Langmuir model effectively described the adsorption isotherms. Ciprofloxacin, enrofloxacin, and norfloxacin showed maximum adsorption capacities (qmax) of 95, 164, and 99 mg g−1, respectively, when HC-150 was used. On the other hand, with PC-500, qmax of 57, 12, and 20 mg g−1 were obtained for ciprofloxacin, enrofloxacin, and norfloxacin, respectively. Although PCA-500 enhanced adsorption capacity compared to PC-500, the qmax remained lower than the results obtained with HC-500, measuring at 51, 102, and 95 mg g−1. These findings emphasize malt bagasse biochar as a viable adsorbent.

Synthesis and Biological Evaluation of Pyrazole-Pyrimidones as a New Class of Correctors of the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR).

Cystic fibrosis (CF) is caused by the functional expression defect of the cystic fibrosis transmembrane conductance regulator (CFTR) protein. Despite the recent success in CFTR modulator development, the available correctors only partially restore the F508del-CFTR channel function, and several rare CF mutations show resistance to available drugs. We previously identified compound 4172 that synergistically rescued the F508del-CFTR folding defect in combination with the existing corrector drugs VX-809 and VX-661. Here, novel CFTR correctors were designed by applying a classical medicinal chemistry approach on the 4172 scaffold. Molecular docking and three-dimensional quantitative structure-activity relationship (3D-QSAR) studies were conducted to propose a plausible binding site and design more potent and effective analogs. We identified three optimized compounds, which, in combination with VX-809 and the investigational corrector 3151, increased the plasma membrane density and function of F508del-CFTR and other rare CFTR mutants resistant to the currently approved therapies.

Molecular basis of inhibition of the amino acid transporter B0AT1 (SLC6A19)

The epithelial neutral amino acid transporter B0AT1 (SLC6A19) is the major transporter for the absorption of neutral amino acids in the intestine and their reabsorption in the kidney. Mouse models have demonstrated that lack of B0AT1 can normalize elevated plasma amino acids in rare disorders of amino acid metabolism such as phenylketonuria and urea-cycle disorders, implying a pharmacological approach for their treatment. Here we employ a medicinal chemistry approach to generate B0AT1 inhibitors with IC50-values of 31-90 nM. High-resolution cryo-EM structures of B0AT1 in the presence of two compounds from this series identified an allosteric binding site in the vestibule of the transporter. Mechanistically, binding of these inhibitors prevents a movement of TM1 and TM6 that is required for the transporter to make a conformational change from an outward open state to the occluded state.

From lab to clinic: The discovery and optimization journey of PI3K inhibitors

PI3K inhibitors have emerged as promising therapeutic agents due to their critical role in various cellular processes, particularly in cancer, where the PI3K pathway is frequently dysregulated. This review explores the evolutionary path of PI3K inhibitors from laboratory discovery to clinical application. The journey begins with early laboratory investigations into PI3K signaling and inhibitor development, highlighting fundamental discoveries that laid the foundation for subsequent advancements. Optimization strategies, including medicinal chemistry approaches and structural modifications, are scrutinized for their contributions to enhancing inhibitor potency, selectivity, and pharmacokinetic properties. The translation from preclinical studies to clinical trials is examined, emphasizing pivotal trials that evaluated efficacy and safety profiles. Challenges encountered during clinical development are critically assessed. Finally, the review discusses ongoing research directions and prospects for PI3K inhibitors, underscoring these agents' continuous evolution and therapeutic potential.

Abstract We110: Novel allosteric ligand designed to prevent Autoantibody targeting the Angiotensin Type 1 Receptor (AT1R) in cardiovascular diseases (CVD)

Background: The clinical data suggest an association of autoantibodies (AAb) targeting angiotensin II type1 receptor (AT1R) and outcomes in heart failure (HF) and preeclampsia. Notably, patient’s risk increases 2 to 4-fold for heart diseases and hypertension. Although AT1R blockers (ARBs) have emerged as a key component in the therapeutic arsenal against CVD, we believe that rather than completely blocking AT1R signaling, maintaining a balanced signaling is crucial for cardiovascular homeostasis. Therefore, we posit that reducing AT1R overactivation and blocking AAb-mediated activation could benefit cardiac health and attenuate the progression of CVD. In our previous study (PMID:36440576), we identified small molecules capable of inhibiting AAb-induced AT1R signaling. Leveraging these observations, we have developed a novel AT1R allosteric ligand that inhibits autoantibody binding to AT1R while still retaining normal AT1R signaling. Methods: Using computational and medicinal chemistry approaches, we designed a series of novel AT1R ligands and obtained compounds with >98% purity through chemical synthesis. Monoclonal antibodies mimicking AT1R-AAb have been generated. Serum samples from dilated cardiomyopathy (DCM) and preeclampsia (PE) patient cohorts were collected and presence of AT1R-AAb was determined using ELISA and epitope-peptide competition studies. Pharmacological characterization of compounds was performed using calcium mobilization, 125I -AngII binding, ex vivo vasoconstriction, and ELISA assays. Results: We identified an AT1R allosteric compound that reduced AngII-mediated calcium signaling with a 5-fold shift in EC 50 . The IC 50 was determined to be 18 µM. It reduces the AngII-mediated vasoconstriction while blocking both monoclonal and patient-derived autoantibody binding with an IC 50 of 5 µM. Conclusion: We have identified a novel AT1R allosteric ligand with negative allosteric modulator (NAM) properties, which has the potential to block autoantibodies and could serve as a new generation of ARBs. Uniquely, it retains beneficial AT1R signaling without competing with AngII, and its allosteric ligand property can be tailored to achieve optimal AT1R signaling.

Recent Updates on Oncogenic Signaling of Aurora Kinases in Chemosensitive, Chemoresistant Cancers: Novel Medicinal Chemistry Approaches for Targeting Aurora Kinases.

The Aurora Kinase family (AKI) is composed of serine-threonine protein kinases involved in the modulation of the cell cycle and mitosis. These kinases are required for regulating the adherence of hereditary-related data. Members of this family can be categorized into aurora kinase A (Ark-A), aurora kinase B (Ark-B), and aurora kinase C (Ark-C), consisting of highly conserved threonine protein kinases. These kinases can modulate cell processes such as spindle assembly, checkpoint pathway, and cytokinesis during cell division. The main aim of this review is to explore recent updates on the oncogenic signaling of aurora kinases in chemosensitive/chemoresistant cancers and to explore the various medicinal chemistry approaches to target these kinases. We searched Pubmed, Scopus, NLM, Pubchem, and Relemed to obtain information pertinent to the updated signaling role of aurora kinases and medicinal chemistry approaches and discussed the recently updated roles of each aurora kinases and their downstream signaling cascades in the progression of several chemosensitive/chemoresistant cancers; subsequently, we discussed the natural products (scoulerine, Corynoline, Hesperidin Jadomycin-B, fisetin), and synthetic, medicinal chemistry molecules as aurora kinase inhibitors (AKIs). Several natural products' efficacy was explained as AKIs in chemosensitization and chemoresistant cancers. For instance, novel triazole molecules have been used against gastric cancer, whereas cyanopyridines are used against colorectal cancer and trifluoroacetate derivatives could be used for esophageal cancer. Furthermore, quinolone hydrazine derivatives can be used to target breast cancer and cervical cancer. In contrast, the indole derivatives can be preferred to target oral cancer whereas thiosemicarbazone-indole could be used against prostate cancer, as reported in an earlier investigation against cancerous cells. Moreover, these chemical derivatives can be examined as AKIs through preclinical studies. In addition, the synthesis of novel AKIs through these medicinal chemistry substrates in the laboratory using in silico and synthetic routes could be beneficial to develop prospective novel AKIs to target chemoresistant cancers. This study is beneficial to oncologists, chemists, and medicinal chemists to explore novel chemical moiety synthesis to target specifically the peptide sequences of aurora kinases in several chemoresistant cancer cell types.

Glycan synthesis: An update

Carbohydrate synthesis presents several challenges due to the intricate nature of molecules and their complex structures. Since certain pathogens are difficult to culture in the laboratory under some circumstances, and the isolation of glycans in pure structural forms is an arduous undertaking, the medicinal chemistry approach offers a fascinating and attractive option. The efforts being made to develop an automated system for oligosaccharide synthesis are expected to produce immense effects and revolutionize the understanding of the role of carbohydrates in biological systems. Glycovaccines aid in saving millions of lives around the world annually by protecting children and adults from bacterial infections. These vaccines further expand the therapeutic armamentarium against several microbial infectious diseases. This review highlights the different clinical applications of glycan and the progress made in their synthetic process.

Abstract 7122: A novel USP1 inhibitor coupled with a novel proteomic response biomarker for precision oncology therapy

Abstract Ubiquitin-specific protease 1 (USP1) is a well-characterized deubiquitinating enzyme (DUB) that plays a critical role in DNA damage repair (DDR). It was shown to regulate various key repair processes, most notably proliferating cell nuclear antigen (PCNA) in the Translesion Repair (TLS) pathway and FANCD2/FANCI in the Fanconi Anemia (FA) repair pathway. Research indicates that USP1 deficiency leads to a decrease in cell survival and disruption of genomic stability, suggesting that USP1 inhibitors (USP1i) may hold promise in treating DDR deficient tumors. Through the integration of computational and medicinal chemistry approaches, we discovered a novel, potent inhibitor of USP1, showing anti-USP1 activity in both cell-free enzymatic assay and in measurement of PCNA-ubiquitination change upon USP1 inhibition in cells. We demonstrate anti tumor activity in DDR-related and other indications. By utilizing our platform to analyze the basal proteomics of resistant and sensitive cell lines treated with USP1i, we revealed a distinctive proteomic biomarker signature for USP1i response. This data demonstrates the potential of our novel USP1 inhibitor to serve as a potent therapeutic agent for DDR-deficient and other biomarker-positive cancer patients. Citation Format: Iris Alchanati, Andrew Morley, Avital Hay-Koren, Fabrizio Fierro, Galina Otonin, Shay Herman, Alon Shtrikman, Yonatan Katzenelenbogen, Gali Arad, Barr Tivon, Kirill Pevzner, Eran Seger. A novel USP1 inhibitor coupled with a novel proteomic response biomarker for precision oncology therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7122.

Abstract 1340: Modulation of the natural killer cell immune response to tumor with a synthetic tumor -immune cell agonist, NK-TICA™

Abstract Natural Killer (NK) cells are highly responsive cytotoxic immune cells of the innate immune system with well characterized anti-tumor properties. Their ability to directly kill malignant cells and elicit an adaptive immune response makes them a promising candidate for a precision guided immunotherapy in oncology. Bicycle® peptides are small (ca.1.5kDa), chemically synthetic, structurally constrained peptides discovered via phage display and optimized using structure-driven design and medicinal chemistry approaches. We have applied the Bicycle® platform technology to discover and evaluate a new class of fully synthetic molecules termed NK tumor immune cell agonists (NK-TICA™). The NK-TICA™ consists of chemically coupled Bicycle® peptides that bind specifically to the key activating receptor, NKp46, and to tumor antigens, that results in highly potent, antigen-dependent receptor activation and NK cell function. We demonstrate potent, selective binding of our Bicycle® peptides to receptor-expressing cells and the capability of the bifunctional molecule to induce NK cell function in vitro. With Bicycle’s novel NK-TICA™ compound, we demonstrate the engagement of NK cells, the specific activation and function of NK cells, and enhanced tumor cytotoxicity in a tumor target- and dose-dependent manner. In conclusion, NK-TICAs drive NK cell-mediated tumor cell killing and cytokine production in vitro and as such have the potential to catalyze the development of durable anti-tumor immunity in tumor types not well served by current therapies. We hypothesize that utilization of Bicycle® NK-TICA™ as a multifunctional immune cell engager will promote the modulation and anti-tumor activity of peripheral and intra-tumoral NK cells to solid tumors. Citation Format: Fay Dufort, Tucker Ezell, Alexandra Rezvaya, Kathleen Ho, Christopher Leitheiser, Philip Brandish, Kevin McDonnell, Nicholas Keen. Modulation of the natural killer cell immune response to tumor with a synthetic tumor -immune cell agonist, NK-TICA™ [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1340.

Abstract 607: Development of a novel, selective, and potent inhibitor of RON kinase

Abstract Purpose: Receptor d’origine nantais (RON) is a highly conserved transmembrane protein expressed at low levels in healthy adult tissues of epithelial origin and at various levels in immune cells such as macrophages. Aberrant activation of RON has been described in many solid tumors, and it contributes to tumorigenesis by modulating the immune tumor microenvironment, activating numerous oncogenic signaling pathways, and protecting tumor cells under stress. The overexpression of RON protein and the subsequent generation of oncogenic variants are mainly responsible for the persistent activation of downstream signaling pathways. In breast cancer, more than 80% of primary cancer samples are positive for RON expression, with overexpression reported in approximately 50% of cases. Importantly, tumoral RON expression correlates with increased breast cancer progression, metastasis, and poor prognosis independent of molecular subtype. We hypothesize that a small molecule inhibitor of RON that can target both full-length and truncated isoforms will promote anti-tumor immunity within the tumor microenvironment and block pro-metastatic signaling pathways. Herein, we report the development of a novel, orally bioavailable, selective, and potent inhibitor of RON kinase. Methods: With structure-guided and iterative medicinal chemistry approaches, we identified a novel chemical entity that potently inhibited RON kinase activity. Further optimization resulted in the identification of ZB-60 with improved potency, selectivity, and desirable drug-like properties. In vitro kinase assays were performed using ADP-Glo RON kinase assay kit (Promega). Changes in phosphorylation of RON was demonstrated by Western blotting. Plasma pharmacokinetics (PK) was conducted in mice to measure exposures and to determine the oral bioavailability of ZB-60. In vivo efficacy of ZB-60 was evaluated in syngeneic mouse models of breast (EMT6) and colorectal (CT26) cancer. Results: ZB-60 inhibited RON kinase activity with an IC50 of 56 nM and showed greater than 40-fold selectivity against MET and other closest members of the tyrosine kinase family. In ZB-60 treated breast cancer cells, there was a dose dependent reduction of RON phosphorylation and downstream signaling. PK analysis showed a high oral bioavailability with low clearance. In vivo evaluation of ZB-60 showed inhibition of tumor growth in EMT6 and CT26 models. Ongoing studies are focused on testing ZB-60 in combination with checkpoint inhibitors. The results from these studies along with ADME-TOX and pharmacokinetics will be presented. Conclusion: ZB-60 has target specific activity and exhibits favorable drug-like properties. Citation Format: Mohan Rao Kaadige, Trason Thode, Jaime Fornetti, Alexis Weston, Serina Ng, Tithi Ghosh-Halder, Taylor Bargenquast, Brian Durbin, Srinivas Kasibhatla, Raffaella Soldi, Alana Welm, Sunil Sharma. Development of a novel, selective, and potent inhibitor of RON kinase [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 607.

Synthesis And Anticancer Activity Of New Hybrid 3-Methylidene-2,3-Dihydro-1,8-Naphthyridinones.

Synthesis of molecular hybrids, obtained by combination of two or more pharmacophoric groups of different bioactive substances in order to produce more efficient drugs, is now a frequently used approach in medicinal chemistry. Following this strategy, we synthetized a library of 3-methylidene-1-tosyl-2,3-dihydro-1,8-naphthyridin-4(1H)-ones, combining a 1,8-naphthyridin-4-one motif with an exo-methylidene bond conjugated with a carbonyl group, pharmacophoric units that are present in many natural, biologically active compounds with anticancer potential. We reasoned that such bifunctional conjugates may have enhanced cytotoxic activity. The title compounds were synthesized in a four step reaction sequence. β-Ketophosphonate, obtained from methyl N-tosylnicotinate and diethyl methylphosphonate, was reacted with various aldehydes giving 3-diethoxyphosphoryl-2,3-dihydro-1,8-naphthyridin-4(1H)-ones as keto-enol tautomers. Later, these compounds were transformed into 3-methylidene-1-tosyl-2,3-dihydro-1,8-naphthyridin-4(1H)-ones applying the Horner-Wadsworth-Emmons methodology. Then, the cytotoxicity of the new compounds was assessed on two cancer cell lines, promyelocytic leukemia HL-60 and breast cancer adenocarcinoma MCF-7, and for comparison, on human umbilical vein endothelial cells HUVEC. The most active and selective analog, 2-ethyl-3-methylidene-1-tosyl-2,3-dihydro-1,8-naphthyridin-4(1H)-one 4 a was chosen for more detailed studies on HL-60 cell line, to determine molecular mechanisms of its anticancer activity. It was shown that 4 a strongly inhibited proliferation and induced apoptosis which could be attributed to its ability to cause DNA damage.

Ligand-based design and synthesis of new trityl histamine and trityl cysteamine derivatives as SIRT2 inhibitors for cancer therapy

The relentless pursuit of novel therapeutic agents against cancer has led to the identification of multiple molecular targets, among which Sirtuin 2 (SIRT2) has garnered significant attention. This study presents an extensive SAR study of our reported trityl scaffold-based SIRT2 inhibitors. This study encompasses a range of different medicinal chemistry approaches to improve the activity of the lead compounds TH-3 and STCY1. The rationally designed and synthesized structures were confirmed using NMR and high-resolution mass spectroscopy before performing SIRT2 inhibition assay, NCI60 cytotoxicity test, and cell cycle analysis. Indeed, our strategies afforded hitherto unreported SIRT2 inhibitors with high activity, particularly 2a, 4a, 7c, and 7f. Remarkably, the presence of a lipophilic para substitution on the phenyl group of a freely rotating or a locked trityl moiety enhanced activity SIRT2 inhibition. Concomitantly, the synthesized compounds showed prominent activity against different cancer lines from the NCI60 assay. Of interest, compound 7c stands out as a potent and highly selective antiproliferative agent against leukemia and colon cancer panels. Furthermore, 7c treatment resulted in cell cycle arrest in MCF-7 cells at G2 phase and did not cause in vitro DNA cleavage.