Potent Selective Inhibitor Research Articles

Obicetrapib exhibits favorable physiochemical and pharmacokinetic properties compared to previous cholesteryl ester transfer protein inhibitors: An integrated summary of results from non-human primate studies and clinical trials.

Anacetrapib, a cholesteryl ester transfer protein (CETP) inhibitor previously under development, exhibited an usually extended terminal half-life and large food effect and accumulated in adipose tissue. Other CETP inhibitors have not shown such effects. Obicetrapib, a potent selective CETP inhibitor, is undergoing Phase III clinical development. Dedicated assessments were conducted in pre-clinical and Phase I and II clinical studies of obicetrapib to examine the pharmacokinetic issues observed with anacetrapib. After 9 months of dosing up to 50 mg/kg/day in cynomolgus monkeys, obicetrapib was completely eliminated from systemic circulation and not detected in adipose tissue after a 13-week recovery period. In healthy humans receiving 1-25 mg of obicetrapib, the mean terminal half-life of obicetrapib was 148, 131, and 121 h at 5, 10, and 25 mg, respectively, and food increased plasma levels by ~1.6-fold with a 10 mg dose. At the end of treatment in Phase II trials, mean plasma levels of obicetrapib ranged from 194.5 ng/mL with 2.5 mg to 506.3 ng/mL with 10 mg. Plasma levels of obicetrapib decreased by 92.2% and 98.5% at four and 15 weeks post-treatment, respectively. Obicetrapib shows no clinically relevant accumulation, is minimally affected by food, and has a mean terminal half-life of 131 h for the 10 mg dose. These data support once daily, chronic dosing of obicetrapib in Phase III trials for dyslipidemia management.

Design, synthesis and biological evaluation of sulfonylurea derivatives as NLRP3 inflammasome inhibitors

The NLRP3 inflammasome has been extensively studied in recent years and its aberrant activation can exacerbate inflammatory responses, contributing to various diseases. MCC950, a sulfonylurea drug, is a potent selective inhibitor of the NLRP3 inflammasome. However, its clinical development was halted due to hepatotoxicity, and studies have indicated significant reduction in activity among its metabolites. Building upon MCC950, we referenced substitution sites of NP3-146 for structural modifications aimed at addressing potential metabolism-related issues. Consequently, we synthesized a series of sulfonylurea derivatives. Ultimately, the optimized compound C4 exhibited a remarkable 80.39 % inhibition of IL-1β at 2 μM, with an IC50 value of 0.805 μM. In conclusion, compound C4 shows potential as a lead compound and warrants further development as an anti-inflammatory NLRP3 inhibitor.

Discovery of reversible and covalent TEAD 1 selective inhibitors MSC-1254 and MSC-5046 based on one scaffold

The Transcriptional Enhanced Associated Domain (TEAD) family of transcription factors are key components of the Hippo signalling family which play a crucial role in the regulation of cell proliferation, differentiation and apoptosis. The identification of inhibitors of the TEAD transcription factors are an attractive strategy for the development of novel anticancer therapies. A HTS campaign identified hit 1, which was optimised using structure-based drug design, to deliver potent TEAD1 selective inhibitors with both a reversible and covalent mode of inhibition. The preference for TEAD1 could be rationalised by steric differences observed in the lower pocket of the palmitoylation-site between subtypes, with TEAD1 having the largest available volume to accommodate substitution in this region.

Design of novel potent selective survivin inhibitors using 2D-QSAR modeling, molecular docking, molecular dynamics, and ADMET properties of new MX-106 hydroxyquinoline scaffold derivatives

Given the critical role of survivin (BIRC5) in tumor cell regulation, developing novel inhibitors represents a promising approach for cancer therapy. This study details the design of innovative survivin inhibitors based on the hydroxyquinoline scaffold of our previously reported lead compound, MX-106. Our study identified nine compounds whose inhibitory activity is expected to be superior to that of the most active molecule in the series. These compounds demonstrated potent suppression of MDA-MB-435 breast cancer cell proliferation in vitro and exhibited enhanced metabolic stability compared to the series' most active member. To evaluate these derivatives as potential survivin inhibitors, we employed a multi-faceted approach combining 2D-QSAR methods, molecular docking, molecular dynamics, and ADMET property assessment. Our molecular modeling studies led to the design of nine novel compounds (Pred1-Pred9) predicted to exhibit potent survivin inhibitory activity based on MLR models. To assess their suitability as drug candidates, we recommend a thorough evaluation of their ADMET properties. These compounds hold promise as innovative anticancer agents targeting survivin, similar to the established MX-106.

Discovery of Potential Inhibitors of CDK1 by Integrating Pharmacophore-Based Virtual Screening, Molecular Docking, Molecular Dynamics Simulation Studies, and Evaluation of Their Inhibitory Activity.

The ability of CDK1 to compensate for the absence of other cell cycle CDKs poses a great challenge to treat cancers that overexpress these proteins. Despite several studies focusing on the area, there are no FDA-approved drugs selectively targeting CDK1. Here, the study aimed to develop potential CDK1 selective inhibitors through drug repurposing and leveraging the structural insights provided by the hit molecules generated. Approximately 280,000 compounds from DrugBank, Selleckchem, Otava and an in-house library were screened initially based on fit values using 3D QSAR pharmacophores built for CDK1 and subsequently through Lipinski, ADMET, and TOPKAT filters. 10,310 hits were investigated for docking into the binding site of CDK1 determined using the crystal structure of human CDK1 in complex with NU6102. The best 55 hits with better docking scores were further analyzed, and 12 hits were selected for 100 ns MD simulations followed by binding energy calculations using the MM-PBSA method. Finally, 10 hit molecules were tested in an in vitro CDK1 Kinase inhibition assay. Out of these, 3 hits showed significant CDK1 inhibitory potential with IC50 < 5 μM. These results indicate these compounds can be used to develop subtype-selective CDK1 inhibitors with better efficacy and reduced toxicities in the future.

Neurotoxicity, Neuroprotection, In Vitro MAOA/MAOB Inhibitory Activity Assessment, Molecular Docking, and Permeability Assay Studies of Newly Synthesized Hydrazones Containing a Pyrrole Ring.

Neurodegenerative diseases such as Parkinson's and Alzheimer's continue to be some of the most significant challenges in modern medicine. Recent research related to the molecular mechanisms of parkinsonism has opened up new approaches to antiparkinsonian therapy. In response to this, we present the evaluation of the potential neuroprotective and MAOA/MAOB inhibitory effects of newly synthesized hydrazones, containing a pyrrole moiety in the carboxyl fragment of the structure. The substances were studied on different brain subcellular fractions, including rat brain synaptosomes, mitochondria, and microsomes. The single application of 50 µM of each compound to the subcellular fractions showed that all substances exhibit a weak neurotoxic effect, with 7b, 7d, and 8d being the least neurotoxic representatives. The corresponding neuroprotective and antioxidant effects were also evaluated in different injury models on subcellular fractions, single out 7b, 7d, and 8d as the most prominent derivatives. A 1 µM concentration of each molecule from the series was also studied for potential hMAOA/hMAOB inhibitory effects. The results revealed a lack of hMAOA activity for all evaluated structures and the appearance of hMAOB effects, with compounds 7b, 7d, and 8d showing effects similar to those of selegiline. The best hMAOB selectivity index (>204) was determined for 7d and 8d, distinguishing these two representatives as the most promising molecules for further studies as potential selective MAOB inhibitors. The performed molecular docking simulations defined the appearance of selective MAOB inhibitory effects based on the interaction of the tested molecules with Tyr398, which is one of the components of the aromatic cage of MAOB and participated in π-π stabilization with the aromatic pyrrole ring. The preliminary PAMPA testing indicated that in relation to the blood-brain barrier (BBB) permeability, the tested pyrrole-based hydrazones may be considered as high permeable, except for 8a and 8e, which were established to be permeable in the medium range with -logP of 5.268 and 5.714, respectively, compared to the applied references.

Effect of halogens on 3-[4-(dimethylamino) phenyl]-1-phenylprop-2-en-1-ones: development of a new class of monoamine oxidase-B inhibitors

Five dimethylamino-based chalcone derivatives (AC) were synthesized and evaluated for their inhibition degree against monoamine oxidase (MAO) enzymes. All AC compounds showed better inhibitory activity against MAO-B than that against MAO-A. AC4 showed the highest inhibitory ability with an IC50 value of 0.020 µM, similar to that of a reference drug safinamide (IC50 = 0.019 µM) against MAO-B, followed by AC1 (IC50 = 0.068 µM) and AC3 (IC50 = 0.083 µM). Substituent -F in ring A (AC4) increased the MAO-B inhibition, followed by -H (AC1), -Br (AC3), and -Cl (AC2). The selectivity index (SI) value of AC4 was high (SI = 82.00) as well as other compounds (44.41 to 98.15). AC4 was found to be a reversible inhibitor as confirmed through analysis using the dialysis method. Interestingly, AC4 was observed to be a noncompetitive MAO-B inhibitor with a rare case and with Ki values of 0.011 ± 0.0036 µM. These experiments confirmed that AC4 is a reversible and potent selective inhibitor of MAO-B. Molecular docking experiments revealed that AC4 showed the highest inhibitory activity with a docking score (-9.510 kcal/mol). A study using molecular dynamics modeling revealed that the protein–ligand complex was more stable. It was observed that AC4 was non-cytotoxic in the study using L929 cell line. In conclusion, compound AC4 shows promise as a MAO-B inhibitor.

Repurposing Duloxetine as a Potent Butyrylcholinesterase Inhibitor: Potential Cholinergic Enhancing Benefits for Elderly Individuals with Depression and Cognitive Impairment.

Despite the advent of new treatment strategies, cholinesterase inhibitors (ChEIs) are still the go-to treatment for dementia disorders. ChEIs act by inhibiting the main acetylcholine-degrading enzyme, acetylcholinesterase (AChE). Nonetheless, accumulating evidence indicates that the impact of inhibition of the sister enzyme, butyrylcholinesterase (BChE), could be even broader in older adults due to the multifaceted role of BChE in several biological functional pathways. Therefore, we employed an in silico modeling-based drug repurposing strategy to identify novel potent BChE inhibitors from the FDA drug database. This was followed by in vitro screening and ex vivo enzyme kinetic validation using human plasma samples as the source of BChE. The analysis revealed that the antidepressant drug, duloxetine, inhibited BChE with high selectivity in comparison to AChE. In contrast, two other antidepressants, namely, citalopram and escitalopram exhibited a weak to moderate activity. Ex vivo enzyme inhibition kinetic analyses indicated that duloxetine acted as a competitive inhibitor of BChE with an inhibition constant (K i) of 210 nM. This K i value is comparable with 100-400 nM concentration of duloxetine following normal dosages in humans, thereby indicating that duloxetine should be able to induce a pharmacologically and biologically relevant in vivo inhibition of BChE. Additionally, we performed the enzyme inhibition kinetic assessment in parallel for ethopropazine, a known potent selective BChE inhibitor, and physostigmine, a dual inhibitor of AChE and BChE. These analyses indicated that duloxetine should be considered a potent BChE inhibitor since its K i was comparable with ethopropazine (K i = 150 nM) but was 4 times smaller than that of physostigmine (K i = 840 nM). In conclusion, this study reports the discovery of duloxetine being a highly potent selective competitive BChE inhibitor. This, in turn, indicates that duloxetine could be the choice of antidepressive treatment in older adults with both depressive and dementia symptoms since it may offer additional clinically beneficial effects via this secondary mode of cholinergic enhancing action.

Unveiling the potential of phytochemicals to inhibit nuclear receptor binding SET domain protein 2 for cancer: Pharmacophore screening, molecular docking, ADME properties, and molecular dynamics simulation investigations.

Nuclear receptor binding SET domain protein 2 (NSD2) significantly contributes to the development of cancer, making it a promising target for cancer drug discovery. This research explores natural compounds as potential selective inhibitors for NSD2 in cancer treatment. Employing a comprehensive in silico approach, the study utilized pharmacophore modeling, molecular docking, pharmacokinetic profiling, and molecular dynamics simulations. An e-pharmacophore model-based screening using the first selective and potent ligand bound to NSD2 identified 49,248 natural compounds from the SuperNatural 3.0 database (containing 449,008 molecules) with acceptable alignment with the developed pharmacophore hypotheses. Subsequently, molecular docking was executed to assess the standout compounds which led to the selection of ten candidates that surpassed the reference inhibitor in accordance w the binding affinity expressed as a G score. Ligand-residue interaction analyses of the top three hits (SN0450102, SN0410255, and SN0142336) revealed diverse crucial interactions with the NSD2 active site, including hydrogen bonds, pi-pi stacking, and hydrophobic contacts with key amino acid residues in the NSD2-PWWP1 domain. Pharmacokinetic profiling confirmed the drug-likability for the refined hits, indicating good cellular permeability and minimal blood-brain barrier penetration. Molecular dynamics simulations for 200 nanoseconds affirmed the stability of protein-ligand complexes, with minimal fluctuations in root mean square deviation and root mean square fluctuation analyses. Overall, this study identified promising natural compounds as potential pharmaceutical agents in the treatment of NSD2-associated cancers.

Non-Small-Cell Lung Cancers (NSCLCs) Harboring RET Gene Fusion, from Their Discovery to the Advent of New Selective Potent RET Inhibitors: "Shadows and Fogs".

RET fusions are relatively rare in Non-Small-Cell Lung Cancers (NSCLCs), being around 1-2% of all NSCLCs. They share the same clinical features as the other fusion-driven NSCLC patients, as follows: younger age, adenocarcinoma histology, low exposure to tobacco, and high risk of spreading to the brain. Chemotherapy and immunotherapy have a low impact on the prognosis of these patients. Multitargeted RET inhibitors have shown modest activity jeopardized by high toxicity. New potent and selective RET inhibitors (RET-Is) (pralsetinib and selpercatinib) have achieved a higher efficacy minimizing the known toxicities of the multitargeted agents. This review will describe the sensitivity of immune-checkpoint inhibitors (ICIs) in RET fusion + NSCLC patients, as well their experiences with the 'old' multi-targeted RET inhibitors. This review will focus on the advent of new potent and selective RET-Is. We will describe their efficacy as well as the main mechanisms of resistance to them. We will further proceed to deal with the new drugs and strategies proposed to overcome the resistance to RET-Is. In the last section, we will also focus on the safety profile of RET-Is, dealing with the main toxicities as well as the rare but severe adverse events.

Inhibition of monoamine oxidases and neuroprotective effects: chalcones vs. chromones.

Eighteen compounds derived from two sub-series, (HC1-HC9) and (HF1-HF9), were synthesized and evaluated for their inhibitory activities against monoamine oxidase (MAO). HC (chalcone) series showed higher inhibitory activity against MAO-B than against MAO-A, whereas the HF (chromone) series showed reversed inhibitory activity. Compound HC4 most potently inhibited MAO-B with an IC50 value of 0.040μM, followed by HC3 (IC50 = 0.049μM), while compound HF4 most potently inhibited MAO-A (IC50 = 0.046μM), followed by HF2 (IC50 = 0.075μM). The selectivity index (SI) values of HC4 and HF4 were 50.40 and 0.59, respectively. Structurally, HC4 (4-OC2H5 in B-ring) showed higher MAO-B inhibition than other derivatives, suggesting that the -OC2H5 substitution of the 4-position in the B-ring contributes to the increase of MAO-B inhibition, especially -OC2H5 (HC4) > -OCH3 (HC3) > -F (HC7) > -CH3 (HC2) > -Br (HC8) > -H (HC1) in order. In MAO-A inhibition, the substituent 4-OC2H5 in the B-ring of HF4 contributed to an increase in inhibitory activity, followed by -CH3 (HF2), -F (HF7), -Br (HF8), -OCH3 (HF3), and-H (HF1). In the enzyme kinetics and reversibility study, the Ki value of HC4 for MAO-B was 0.035 ± 0.005μM, and that of HF4 for MAO-A was 0.035 ± 0.005μM, and both were reversible competitive inhibitors. We confirmed that HC4 and HF4 significantly ameliorated rotenone-induced neurotoxicity, as evidenced by the reactive oxygen species and superoxide dismutase assays. This study also supports the significant effect of HC4 and HF4 on mitochondrial membrane potential in rotenone-induced toxicity. A lead molecule was used for molecular docking and dynamic simulation studies. These results show that HC4 is a potent selective MAO-B inhibitor and HF4 is a potent MAO-A inhibitor, suggesting that both compounds can be used as treatment agents for neurological disorders.

Fisetin is a selective adenosine triphosphate-competitive inhibitor for mitogen-activated protein kinase kinase 4 to inhibit lipopolysaccharide-stimulated inflammation.

The mitogen-activated protein kinase kinase 4 (MKK4), a member of the MAP kinase kinase family, directly phosphorylates and activates the c-Jun NH2-terminal kinases (JNK), in response to proinflammatory cytokines and cellular stresses. Regulation of the MKK4 activity is considered to be a novel approach for the prevention and treatment of inflammation. The aim of this study was to identify whether fisetin, a potential anti-inflammatory compound, targets MKK4-JNK cascade to inhibit lipopolysaccharide (LPS)-stimulated inflammatory response. RAW264 macrophage pretreated with fisetin following LPS stimulation was used as a cell model to investigate the transactivation and expression of related-inflammatory genes by transient transfection assay, electrophoretic mobility shift assay (EMSA), or enzyme-linked immunosorbent assay (ELISA), and cellular signaling as well as binding of related-signal proteins by Western blot, pull-down assay and kinase assay, and molecular modeling. The transactivation and expression of cyclooxygenase-2 (COX-2) gene as well as prostaglandin E2 (PGE2) secretion induced by LPS were inhibited by fisetin in a dose-dependent manner. Signaling transduction analysis demonstrated that fisetin selectively inhibited MKK4-JNK1/2 signaling to suppress the phosphorylation of transcription factor AP-1 without affecting the NF-κB and Jak2-Stat3 signaling as well as the phosphorylation of Src, Syk, and TAK1. Furthermore, in vitro and ex vivo pull-down assay using cell lysate or purified protein demonstrated that fisetin could bind directly to MKK4. Molecular modeling using the Molecular Operating Environment™ software indicated that fisetin docked into the ATP-binding pocket of MKK4 with a binding energy of -71.75 kcal/mol and formed a 1.70 Å hydrogen bound with Asp247 residue of MKK4. The IC50 of fisetin against MKK4 was estimated as 2.899 μM in the kinase assay, and the ATP-competitive effect was confirmed by ATP titration. Taken together, our data revealed that fisetin is a potent selective ATP-competitive MKK4 inhibitor to suppress MKK4-JNK1/2-AP-1 cascade for inhibiting LPS-induced inflammation.

Mitigating the resistance of MCF-7 cancer cells to Doxorubicin under hypoxic conditions with novel coumarin based carbonic anhydrase IX and XII inhibitors

In the present study, the design and synthesis of novel coumarin derivatives 8a-h, 11a-d and 16a-c as potential selective inhibitors for the tumor associated human carbonic anhydrase isoforms (hCA IX and XII) was reported. All the newly synthesized derivatives showed potent to mild activity against the targeted CA IX (KI = 0.08–9.57 µM), with selectivity indices over CA I (SI = 2.0–21.9) and over CA II (SI = 1.1–15.7). They showed similar activities against CA XII (KI = 0.06–9.48 µM) with selectivity indices over CA I (SI = 1.4–21.2) and CA II (SI = 0.9–15.5). Compound 16b featuring sulfonamide function possessed promising inhibitory activities against the targeted isoforms CA IX and XII with KI values of 0.08 and 0.06 µM, respectively. Interestingly, it was found that using compound 16b at a nontoxic concentration as an adjuvant with Doxorubicin against MCF-7 cells enhanced the cytotoxicity under hypoxia by almost 3.5 folds; IC50 decreased from 25.74 to 7.43 µM. Therefore, compound 16b restored the cytotoxicity of Doxorubicin against MCF-7 cells under hypoxia, almost as normoxia. Furthermore, flow cytometry analysis of a combination treatment of compound 16b and Doxorubicin to the MCF7 cell line revealed an increase in cell cycle arrest at the G2/M phase and a more efficient apoptotic effect than Doxorubicin alone. Furthermore, compound 16b showed no cytotoxicity against normal breast MCF-10A cell line (IC50 = 296.25 µM).

Structural modification of 2-phenylquinoline-4-carboxylic acid containing SIRT3 inhibitors for the cancer differentiation therapy.

Inhibition of SIRT3 exhibited potency in triggering leukemic cell differentiation. In discovery of potent SIRT3 inhibitors for cancer differentiation therapy, structural modification was performed on the previously developed lead compound P6. A total of 33 compounds were designed and synthesized. In the enzyme inhibitory assay, several molecules S18, S26, S27 and T5 showed potent SIRT3 inhibitory activity with IC50 value of 0.53, 1.86, 5.06, and 2.88 μM, respectively. Moreover, the tested compounds exhibited SIRT3 inhibitory selectivity over SIRT1 and SIRT2. Compounds S27 and T5 were potent in inhibition the growth of MM1.S and RPMI-8226 cells in the invitro antiproliferative test. Significantly, representative compounds, especially S27 and T5, promoted differentiation of tested MM cells in the cellular morphological evaluation, accompanied by increasing the expression of differentiation antigen CD49e and human immunoglobulin light chain lambda and kappa. Additionally, molecule S18 without antiproliferative potency itself, showed significant inhibitory activity against growth factor IL-6 induced RPMI-8226 cell proliferation. Collectively, potent SIRT3 selective inhibitors with MM cell differentiation potency were developed for further discovery of anticancer drugs.

Design, synthesis and biological evaluation of novel SIRT3 inhibitors targeting both NAD+ and substrate binding sites for the treatment of acute myeloid leukemia

Acute myeloid leukemia (AML) represents a highly malignant subtype of leukemia with limited therapeutic options. In this study, we propose a novel therapeutic strategy for treating AML by inhibiting SIRT3 to regulate mitochondrial metabolism network involved in energy metabolism and epigenetic modifications essential for AML survival. A series of thieno [3,2-d]pyrimidine-6-carboxamide derivatives were designed and synthesized by structure-based strategy, 17f was documented to be a potent and acceptable selective SIRT3 inhibitor with IC50 value of 0.043 μM and exhibited profound anti-proliferative activity in MOLM13, MV4-11, and HL-60 cells. Through CETSA assay and the degree of deacetylation of intracellular SIRT3 substrates, we confirmed that 17f could effectively bind and inhibit SIRT3 activity in AML cells. Mechanistically, 17f suppressed mitochondrial function, triggered the accumulation of ROS, and significantly inhibited the production of ATP in AML cells. With the breakdown of mitochondrial function, 17f eventually induced apoptosis of AML cells. In addition, 17f also showed excellent anti-AML potential in nude mouse tumor models of HL-60-Luc. Collectively, these results demonstrate that 17f is a potent and acceptable selective SIRT3 inhibitor with promising potential to treat AML.

Discovery of Potent Selective HDAC6 Inhibitors with 5-Phenyl-1H-indole Fragment: Virtual Screening, Rational Design, and Biological Evaluation.

Among the HDACs family, histone deacetylase 6 (HDAC6) has attracted extensive attention due to its unique structure and biological functions. Numerous studies have shown that compared with broad-spectrum HDACs inhibitors, selective HDAC6 inhibitors exert ideal efficacy in tumor treatment with insignificant toxic and side effects, demonstrating promising clinical application prospect. Herein, we carried out rational drug design by integrating a deep learning model, molecular docking, and molecular dynamics simulation technology to construct a virtual screening process. The designed derivatives with 5-phenyl-1H-indole fragment as Cap showed desirable cytotoxicity to the various tumor cell lines, all of which were within 15 μM (ranging from 0.35 to 14.87 μM), among which compound 5i had the best antiproliferative activities against HL-60 (IC50 = 0.35 ± 0.07 μM) and arrested HL-60 cells in the G0/G1 phase. In addition, 5i exhibited better isotype selective inhibitory activities due to the potent potency against HDAC6 (IC50 = 5.16 ± 0.25 nM) and the reduced inhibitory activities against HDAC1 (selective index ≈ 124), which was further verified by immunoblotting results. Moreover, the representative binding conformation of 5i on HDAC6 was revealed and the key residues contributing 5i's binding were also identified via decomposition free-energy analysis. The discovery of lead compound 5i also indicates that virtual screening is still a beneficial tool in drug discovery and can provide more molecular skeletons with research potential for drug design, which is worthy of widespread application.

Repurposing of known drugs from multiple libraries to identify novel and potential selective inhibitors of HDAC6 via in silico approach and molecular modeling

Histone deacetylase 6 (HDAC6, Class IIb) is a promising target for anticancer drugs. So far, few nonselective HDAC inhibitors have received regulatory approval as anticancer agents. However, they are associated with cell toxicity. Thus, isoform-selective inhibitors may be desirable. Here, we conducted structure-based virtual screening of multiple libraries containing a total of 2,250,135 compounds against HDAC6. The top hits with good docking scores and potential selectivity over HDAC10 (Class IIb) were submitted to 100 ns molecular dynamics simulation to monitor their dynamic behaviors and stability in the binding pockets of these enzymes. Furthermore, the drug-likeness and ADMET properties of these hits were estimated computationally. Four diverse compounds from different sources, including NCI and ZINC databases (BDH33926500, CID667061, Cromolyn, and ZINC000103531486), show potential selectivity for HDAC6.

Abstract PO-036: Targeting the CBM signalosome with a MALT1 scaffolding inhibitor for treatment of non-Hodgkin lymphomas

Abstract Introduction: The CBM signalosome (CARDs/BCL10/MALT1) is an evolutionarily conserved key regulator of canonical NF-κB signaling. Activating mutations of the CBM signalosome constitutively activate NF-κB, driving tumorigenesis in B-cell Non-Hodgkin Lymphoma (B-NHL). Depletion of individual components of the CBM complex including MALT1 was shown preclinically to suppress NF-κB driven Activated B-Cell Diffuse Large B-Cell Lymphoma (ABC-DLBCL), inspiring many efforts to develop MALT1 inhibitors for therapeutic use. MALT1 is a dual function protein with two independent roles. Primarily, MALT1 is a scaffold protein organizing the CBM complex and directly transducing canonical NF-κB signaling. Secondarily, MALT1 is a paracaspase, fine-tuning multiple signaling pathways, including NF-κB, via substrate cleavage. Research indicates that targeting MALT1 scaffolding activity is likely the preferred approach for effectively suppressing NF-κB activity while minimizing impact on the immune system. Using our Smart AllosteryTM platform, we have developed potentially the first-in-class MALT1 scaffolding inhibitors targeting the CBM signalosome as a more directed approach to specifically block NF-κB signaling. Here, we disclose the distinctive mechanism of action of scaffolding inhibitors. Experiments: The mechanistic studies of MALT1 scaffolding inhibition were explored through comprehensive cellular assays and in vivo analyses. Engineered cell models were utilized to elucidate novel mechanisms of action. Results: We have developed a series of potent MALT1 scaffolding selective inhibitors with cellular IC50 values approximating 250nM for scaffolding activity, 80nM for NF-κB activity, and 590nM for AP-1 activity. Using TR-FRET, NanoBRET, and TurboID assays, we observed scaffolding inhibitors did not interrupt the interaction of MALT1-TRAF6. Rather, they induced a non-productive signalosome blocking NF-κB activity. Scaffolding inhibitors did not inhibit MALT1 protease activity; in fact, inhibition of MALT1 scaffolding activity modestly increased its protease activity, which is consistent with observations in MALT1 scaffolding mutant mice. This distinctive consequence of MALT1 scaffolding inhibition translated to no detrimental effects on T-cell activation or Treg differentiation, both of which are dependent on MALT1 protease activity and cause associated safety concerns with chronic MALT1 protease inhibitor treatment. The distinct and superior mode of action of MALT1 scaffolding inhibitors manifested in a more potent and broad anti-proliferative activity against a panel of B-NHL cell lines dependent on intrinsic BCR or NF-κB activity for growth. Conclusions: The potential first-in-class MALT1 scaffolding inhibitor offers what we believe is a best-in-class approach to targeting CBM-complex-driven NF-κB signaling. Scaffolding inhibitors effectively blocked both NF-κB and AP-1 signaling without impairing protease activity and avoided negative effects on T-cell function. Scaffolding inhibitors offer a promising therapeutic approach for NF-kB driven cancers. Citation Format: Yi Yao, Kevin Ling, Huili Xia, Huadong Sun, Yingzhi Bi, Jun Kuai, Joe Wahle, Wei Liu, Ken Carson, Gerry Harriman, Fang Wang. Targeting the CBM signalosome with a MALT1 scaffolding inhibitor for treatment of non-Hodgkin lymphomas [abstract]. In: Proceedings of the Fourth AACR International Meeting on Advances in Malignant Lymphoma: Maximizing the Basic-Translational Interface for Clinical Application; 2024 Jun 19-22; Philadelphia, PA. Philadelphia (PA): AACR; Blood Cancer Discov 2024;5(3_Suppl):Abstract nr PO-036.

Identifying potential drug targets in the kinomes of two monogenean species.

Protein kinases are enzymes involved in essential biological processes such as signal transduction, transcription, metabolism, and the cell cycle. Human kinases are targets for several drugs approved by the US Food and Drug Administration. Therefore, the identification and classification of kinases in other organisms, including pathogenic parasites, is an interesting subject of study. Monogeneans are platyhelminths, mainly ectoparasites, capable of causing health problems in farmed fish. Although some genomes and transcriptomes are available for monogenean species, their full repertoire of kinases is unknown. The aim of this study was to identify and classify the putative kinases in the transcriptomes of two monogeneans, Rhabdosynochus viridisi and Scutogyrus longicornis, and then to predict potential monogenean drug targets (MDTs) and selective inhibitor drugs using computational approaches. Monogenean kinases having orthologs in the lethal phenotype of C. elegans but not in fish or humans were considered MDTs. A total of 160 and 193 kinases were identified in R. viridisi and S. longicornis, respectively. Of these, 22 kinases, belonging mainly to the major groups CAMK, AGC, and TK, were classified as MDTs, five of which were evaluated further. Molecular docking analysis indicated that dihydroergotamine, ergotamine, and lomitapide have the highest affinity for the kinases BRSK and MEKK1. These well-known drugs could be evaluated in future studies for potential repurposing as anti-monogenean agents. The present study contributes valuable data for the development of new antiparasitic candidates for finfish aquaculture.

Depletion of histone H3K27 demethylase exerts anti-tumor activity as a monotherapy and in combination therapy with ceralasertib in non-small cell lung carcinoma.

e20035 Background: Lung cancer is one of the most frequently diagnosed cancers and is the leading cause of cancer-related death worldwide. Non-small cell lung carcinoma (NSCLC) represents 85% of lung cancers and is the most common type with poor prognosis. The lysine-specific demethylase UTX (gene name KDM6A) demethylates H3K27me2/3 at genes and enhancers and have been shown to support oncogenic transcription factors. We hypothesize that UTX is a highly pleiotropic factor in tumorigenesis and may plays a critical role in controlling DNA replication-associated gene activation as well as in replication stress-related DNA damage repair. Methods: To evaluate the role of UTX in tumorigenesis, shRNA-mediated UTX knockdown was employed in NCI-H1975 cells followed by cell cycle and cell proliferation assays. In the UTX-knocked down NCI-H1975 cells, target genes involved in DNA replication and DNA damage repair were discovered by RNA sequencing and further validated with RT-qPCR. Effects of UTX depletion on DNA replication and radiation-induced DNA repair were analyzed by immunofluorescence. Effects of UTX depletion on cell cycle arrest and the ATR–CHK1 checkpoint signaling pathway were analyzed by flow cytometry and immunoblotting. In vivo response to UTX inhibition monotherapy (UTX knockdown) and combination therapy of UTX knockdown with ceralasertib, a selective ATR kinase inhibitor, was evaluated in dox-inducible UTX knockdown NCI-H1975 xenografts. Results: Induction of UTX knockdown significantly reduced the NCI-H1975 tumor volume compared to the control group, showing anti-tumor activity. Furthermore, loss of UTX induced hyperactivation of ATR–CHK1 checkpoint signaling pathway, suggesting the UTX-depleted tumor cells attempt to alleviate replication stress to escape from apoptosis. To inhibit the UTX-depletion induced ATR–CHK1 pathway, ceralasertib (formerly AZD6738), an oral potent selective inhibitor of ATR, was combined with UTX-knockdown for in vitro and in vivo evaluation. Consistent with in vitro cell-based assay, combination therapy of ceralasertib with UTX depletion showed enhanced tumor growth inhibition and regression in the NCI-H1975 xenograft model. Conclusions: Our findings provide new insights into a pro-oncogenic role of UTX in supporting tumor maintenance via engaging DNA replication and repair pathway. Depletion of UTX alone may serve as a new therapeutic target in non-small cell lung carcinoma; and further combination with ceralasertib enhances the anti-tumor activity of UTX knockdown by inhibiting the ATR–CHK1 checkpoint signaling pathway.