Structural Optimization of Isoquinoline Derivatives from Lycobetaine and Their Inhibitory Activity against Neuroendocrine Prostate Cancer Cells.

Neuroendocrine prostate cancer (NEPC) is a highly aggressive cancer that is resistant to hormone therapy and characterized by poor prognosis, as well as limited therapeutic options. Since the natural product lycobetaine was reported to exhibit good antitumor activities against various types of cancers, we initially simplified the scaffold of lycobetaine to obtain the active compound 1, an isoquinoline derivative with an aryl moiety substitution at the 4-position, which showed apparent antiproliferative activities against NPEC cell line LASCPC-01 in vitro. Subsequently, we carried out structural optimization and systematic structure-activity relationship (SAR) studies on compound 1, leading to the discovery of compound 46, which demonstrated potent inhibitory activities against the LASCPC-01 cell line with an IC50 value of 0.47 µM. Moreover, compound 46 displayed remarkable selectivity over prostate cancer cell line PC-3 with a selectivity index greater than 190-fold. Further cell-based mechanism studies revealed that compound 46 and lycobetaine can effectively induce G1 cell cycle arrest and apoptosis dose dependently. However, lycobetaine inhibited the expression of neuroendocrine markers, while compound 46 slightly upregulated these proteins. This suggested that compound 46 might exert its antitumor activities through a different mechanism than lycobetaine, warranting further study.

A novel BODIPY-based theranostic agent for in vivo fluorescence imaging of cerebral Aß and ameliorating Aß-associated disorders in Alzheimer's disease transgenic mice.

ß-Amyloid (Aß) aggregation is increasingly recognized as both a biomarker and an inducer of the progression of Alzheimer's disease (AD). Here, we describe a novel fluorescent probe P14, developed based on the BODIPY structure, capable of simultaneous visualization and inhibition of Aß aggregation in vivo. P14 shows high binding affinity to Aß aggregates and selectively labels Aß plaques in the brain slices of APP/PS1 mice. Moreover, P14 is able to visualize overloaded Aß in both APP/PS1 and 5 × FAD transgenic mice in vivo. From the aspect of potential therapeutic effects, P14 administration inhibits Aß aggregation and alleviates Aß-induced neuronal damage in vitro, as well as reduces central Aß deposition and ameliorates cognitive impairment in APP/PS1 transgenic mice in vivo. Finally, P14 is applied to monitor the progression of Aß aggregation in the brain of 5 × FAD transgenic mice and the intervention effect itself by fluorescence imaging. In summary, the discovery of this fluorescent agent might provide important clues for the future development of theranostic drug candidates targeting Aß aggregation in AD.

A novel phthalazinone derivative as a capsid assembly modulator inhibits hepatitis B virus expression.

Development of new anti-hepatitis B virus (HBV) drugs that target viral capsid assembly is a very active research field. We identify a novel phthalazinone derivative, compound 5832, as a potent HBV inhibitor. In this study, we intend to elaborate the antiviral effect and mechanism of 5832 against HBV in vitro and in vivo. Compound 5832 treatment induces the formation of genome-free empty capsid by interfering with the core protein assembly domain, which significantly decreases the extracellular and intracellular HBV DNA. In the AAV-HBV transduced mouse model, 5832 suppresses serum HBV DNA after 4-week treatment, and decreases HBsAg and HBeAg levels. 5832 treatment also reduces intrahepatic HBV RNA, DNA and HBcAg levels. During the follow-up period after treatment withdrawal, serum antigen levels demonstrated no increase. We demonstrate 5832 treatment could active apoptotic signaling by elevating the expression of death receptor 5 (DR5), which participated in corresponding HBcAg-positive hepatocyte eradication. Phthalazinone derivative 5832 may serve as a promising anti-HBV drug candidate to improve the treatment options for chronic HBV infection.

Degradation of Cyclin-Dependent Kinase 9/Cyclin T1 by Optimized Microtubule-Associated Protein 1 Light Chain 3 Beta-Recruiting Coumarin Analogs.

Autophagy is an efficient and attractive protein degradation pathway in addition to the ubiquitin-proteasome system. Herein, systematic optimization of coumarin analogs linked with the CDK9 inhibitor SNS-032 is reported that may bind to cyclin-dependent kinase 9 (CDK9) and microtubule-associated protein 1 light chain 3 beta (LC3B) simultaneously, which leads to the selective autophagic degradation of targeted CDK9/cyclin T1 and is different from the PROTAC degrader THAL-SNS-032. Further mechanism studies revealed an autophagy-lysosome pathway, where the degraders possibly formed a ternary complex with CDK9 and LC3B. In addition, degrader 10 showed antitumor efficacy in vivo. Our work optimized a potent LC3B recruiter and demonstrated the feasibility of autophagy-tethering compounds (ATTECs), which could be applied for the degradation of diverse intracellular pathogenic proteins to treat related diseases.

Anti-melanoma differentiation-associated gene 5 and anti-Ro52 antibody-dual positive dermatomyositis accompanied by rapidly lung disease: Three case reports.

BACKGROUND: Clinically amyopathic deramatomyositis was manifested as the various cutaneous dermatomyositis (DM) manifestations without muscle weakness. Anti-melanoma differentiation-associated gene 5 (anti-MDA5) and anti-Ro52 antibody-dual positive clinically amyopathic DM patients are at a high risk of developing rapidly progressive interstitial lung disease, and they exhibit an immensely high half-year mortality. CASE SUMMARY: We presented three patients with anti-MDA5 and anti-Ro52 antibody-dual positive DM patients and we reviewed the previous studies on the link between anti-MDA5 and anti-Ro52 antibody-dual positive DM. Although we aggressively treated these patients similarly, but they all exhibited different prognoses. We reviewed the importance of clinical cutaneous rashes as well as the pathogenesis and treatment in the dual positive anti-MDA5 and anti-Ro52 associated DM. CONCLUSION: Patients with anti-MDA5 anti-Ro52 antibody-dual positive DM should be accurately diagnosed at an early stage and should be treated aggressively, thus, the patient's prognosis can be significantly modified.

Discovery of (S)-N-(2-Amino-4-fluorophenyl)-4-(1-(3-(4-((dimethylamino)methyl)phenyl)-6-oxopyridazin-1(6H)-yl)ethyl)benzamide as Potent Class I Selective HDAC Inhibitor for Oral Anticancer Drug Candidate.

A novel series of benzamide derivatives were successively designed and synthesized prepared from the pyridazinone scaffold. Among them, (S)-17b, demonstrated potent inhibitory activity in vitro toward human class I HDAC isoforms and human myelodysplastic syndrome (SKM-1) cell line. Also, (S)-17b strongly increased the intracellular level of acetyl-histone H3 and P21 simultaneously and effectively induced G1 cell cycle arrest and apoptosis. Through oral dosing in SKM-1 xenograft models, (S)-17b exhibited excellent in vivo antitumor activity. In addition, compound (S)-17b showed better antitumor efficacy on mouse models with intact immune system than those with thymus deficiencies. Furthermore, this compound displayed a favorable pharmacokinetic profile in ICR mice and SD rat, respectively, minimal metabolic property differences among hepatocytes from five species, and a low inhibition upon the human ether-a-go-go (hERG) channel with an IC50 value of 34.6 µΜ. This novel compound (S)-17b may serve as a new drug candidate for further investigation.

A prodrug of the capsid assembly modulator improved druggability and lowing HBsAg and HBeAg for the treatment of chronic hepatitis B.

CAMs were disclosed to alter cccDNA levels with sustained hepatitis B surface antigen (HBsAg) loss or seroconversion in preclinical investigation. Here, we report the discovery of a prodrug Yhhu6669 as CAMs based on the intestinal peptide transporter. This compound exhibited the promising anti-HBV activity with sustained suppression of HBV DNA, as well as HBsAg and HBeAg in the AAV HBV mouse model by oral treatment for 7 weeks and maintained for a further 8 weeks following drug withdraw. Our results show an alternative possibility for a functional cure by specific CAMs and provide the basis for the further mechanism study.

Discovery of selective NaV1.8 inhibitors based on 5-chloro-2-(4,4-difluoroazepan-1-yl)-6-methyl nicotinamide scaffold for the treatment of pain.

The NaV1.8 channel is a genetically validated target for pain and it is mostly expressed in the peripheral nervous system. Based on the disclosed structures of NaV1.8-selective inhibitors, we designed and synthesized a series of compounds by introducing bicyclic aromatic fragments based on the nicotinamide scaffold. In this research, a systematic structure-activity relationship study was carried out. While compound 2c possessed moderate inhibitory activity (IC50 = 50.18 ± 0.04 nM) in HEK293 cells stably expressing human NaV1.8 channels, it showed potent inhibitory activity in DRG neurons and isoform selectivity (>200-fold against human NaV1.1, NaV1.5 and NaV1.7 channels). Moreover, the analgesic potency of compound 2c was identified in a post-surgical mouse model. These data demonstrate that compound 2c can be further evaluated as a non-addictive analgesic agent with reduced cardiac liabilities.

Treatment of paradoxical eczematous eruption in psoriasis treated with secukinumab: A case report.

RATIONALE: Eczematous eruption is an increasingly recognized form of drug-related eruption, typically reported in association with interleukin 17 (IL-17)A inhibitors. However, severe paradoxical eczematous eruption due to IL-17A inhibitors has been rarely reported. Herein, we reported a case of a man with severe psoriasis with erythematous scaly plaques on the scalp, trunk, and arms and legs after the administration of secukinumab was initiated. PATIENT CONCERNS: We reported a case of a 20-year-old man with severe psoriasis with erythematous scaly plaques on the scalp, trunk, and arms and legs after the administration of secukinumab was initiated. A skin biopsy was performed. It revealed spongiotic dermatitis consistent with eczematous reaction. Direct and indirect immunofluorescence assays were negative. DIAGNOSES: He was diagnosed with eczematous eruption. INTERVENTIONS: Discontinuation of secukinumab and administration of cyclosporine and prednisone were considered. OUTCOMES: Significant improvement was observed, with no adverse events. CONCLUSION: Our case shows that eczematous eruption can paradoxically occur in patients on IL-17A inhibitors and this report is expected to increase awareness of the rising number of cutaneous eruptions related to biological agents.

Protein C-Terminal Tyrosine Conjugation via Recyclable Immobilized BmTYR.

Protein modification plays an essential role in biological and pharmaceutical research. Due to the ordinary selectivity and inevitable damage to proteins of chemical synthetic methods, increased efforts were focused on biocatalysts which exhibited high regioselectivity and mild reaction conditions. However, separation of the biocatalysts and modified proteins remained a problem, especially when scaling up. Here, we developed a simple method for site-specific protein modification with a recyclable biocatalyst. The immobilizing tyrosinase (BmTYR) on magnetic beads can oxidize C-terminal tyrosine residues of the target protein to o-quinone, followed by the spontaneous addition of different nucleophiles (e.g., aniline derivatives), resulting in a C-terminal modified protein. Compared to the homogeneous biocatalytic system reported before, this heterogeneous system leads to an easier separation. Furthermore, the solid-phase biocatalyst can be regenerated during separation, providing reusability and lower costs.

Discovery of potent ebola entry inhibitors with (3S,4aS,8aS)-2-(3-amino-2-hydroxypropyl) decahydroisoquinoline-3-carboxamide scaffold.

Ebola virus (EBOV), one member of the family Filoviridae, can causes hemorrhagic fever and other severe diseases in humans with a high mortality rate (25-90%). Until recently, there were no approved drugs and very limited treatment method for Ebola virus disease. In this study, we discovered a series of potent Ebola entry inhibitors with the (3S,4aS,8aS)-2-(3-amino-2-hydroxypropyl)decahydroisoquinoline-3-carboxamide scaffold from high-throughput screening in reported pseudotyped virus system. Further optimization resulted a most potent compound 28 (IC50= 0.05 µM, SI = 98), which displayed 3-fold potency compared to the known inhibitor Toremifene (IC50= 0.17 µM, SI = 55). Moreover, compound 28 exhibited the remarkable selectivity between EBOV-GP and VSV-G (Spec. Index = 58), thus could exclude nonspecific effects. Structure-activity relationship and molecular docking analysis of the new chemical scaffold provided more information on the binding modes and the spare volume at the binding cavity, thus can guide the design of the further potent compounds.

Adjusted degradation of BRD4 S and BRD4 L based on fine structural modifications of the pyrrolopyridone scaffold.

Novel pyrrolopyridone BET degraders were designed and synthesized based on the binding mode between the pyrrolopyridone BET inhibitor with the BRD4 protein. The potent degraders on MV-4-11 cells were discovered through structure-activity relationship study. Modification of warhead on pyrrolopyridone BET degraders significantly regulates BRD4 isoform (long and short) protein degradation, which induces differential cell cycle arrest and apoptosis on MV-4-11 cells. Docking study revealed that the fine structural modification of BET degraders may bind with the BD domain of BRD4 protein to engage various surface areas that bind with CRBN.

Indoles Oxidative Ring-Opening/Cyclization Cascade with the 1,2-Diaminoarenes: Direct Synthesis of 2-Aryl-3-(2-aminoaryl)quinoxalines.

A mild oxidative sequential tandem reaction was developed to rapidly generate 2-aryl-3-(2-aminoaryl) quinoxalines. This method exploited 2-substituted indoles as substrate to form quinoxalines in a one-pot reaction. The key to this tandem reaction was the formation of 3-iodoindoles, which underwent Kornblum-type oxidation with DMSO to generate active imine 2-substitued 3H-indol-3-ones. The active imines were captured in situ by 1,2-diaminobenzenes to construct diverse quinoxalines. The transformation can be accomplished at room temperature with excellent functional group tolerance.

Discovery of highly potent SARS-CoV-2 Mpro inhibitors based on benzoisothiazolone scaffold.

The COVID-19 pandemic has drastically impacted global economies and public health. Although vaccine development has been successful, it was not sufficient against more infectious mutant strains including the Delta variant indicating a need for alternative treatment strategies such as small molecular compound development. In this work, a series of SARS-CoV-2 main protease (Mpro) inhibitors were designed and tested based on the active compound from high-throughput diverse compound library screens. The most efficacious compound (16b-3) displayed potent SARS-CoV-2 Mpro inhibition with an IC50 value of 116 nM and selectivity against SARS-CoV-2 Mpro when compared to PLpro and RdRp. This new class of compounds could be used as potential leads for further optimization in anti COVID-19 drug discovery.

Discovery of Potent Antiallergic Agents Based on an o-Aminopyridinyl Alkynyl Scaffold.

Effective therapeutic agents are highly desired for immune-mediated allergic diseases. Herein, we report the design, synthesis, and structure-activity relationship of an o-aminopyridinyl alkyne series as novel orally bioavailable antiallergic agents, which was identified through phenotypic screening. Compound optimization yielded a highly potent compound 36, which effectively suppressed mast cell degranulation in a dose-dependent manner (IC50, 2.54 nM for RBL-2H3 cells; 48.28 nM for peritoneal mast cells (PMCs)) with a good therapeutic index. It also regulated the activation of FcεRI-mediated downstream signaling proteins in IgE/Ag-stimulated RBL-2H3 cells. In addition, 36 exhibited excellent in vivo pharmacokinetic properties and antiallergic efficacy in both passive systemic anaphylaxis (PSA) and house dust mite (HDM)-induced murine models of pulmonary allergic inflammation. Furthermore, preliminary analysis of the kinases profile identified Src-family kinases as potential targets for 36. Compound 36 may serve as a new valuable lead compound for future antiallergic drug discovery.

The Novel RET Inhibitor SYHA1815 Inhibits RET-Driven Cancers and Overcomes Gatekeeper Mutations by Inducing G1 Cell-Cycle Arrest through c-Myc Downregulation.

Rearranged during transfection (RET), an oncogenic driver, has been found in multiple tumor types and is thus a promising anticancer therapeutic target. Novel selective RET inhibitors (RETi) that can overcome V804 gatekeeper mutations, endowing resistance to multikinase inhibitors (MKI) and, in particular, achieving KDR selectivity, are needed. In addition, the mechanisms underlying RET-inhibition-induced antiproliferative effects in the context of RET addiction are incompletely understood. This study describes a novel selective RETi, SYHA1815, which inhibited the kinase activity of RET wild type and V804 mutant with an IC50 in the subnanomolar to nanomolar range. Notably, SYHA1815 exhibited approximately 20-fold selectivity for RET over KDR, almost equivalent to that of the launched selective inhibitor pralsetinib. SYHA1815 had only a marginal inhibitory effect on cellular KDR signaling at a high (200 nmol/L) concentration, confirming the selectivity over KDR. In addition, SYHA1815 exhibited a favorable selectivity profile, with greater than 100-fold selectivity for RET over 347 other kinases. It exhibited potent antitumor efficacy and overcame V804 mutations in vitro and in vivo by targeting RET. Then, using SYHA1815 as a probe, we found that RET inhibition suppressed RET-driven cell proliferation via G1 cell-cycle arrest through downregulating c-Myc. Furthermore, disruption of c-Myc upon Brd4 inhibitor treatment led to G1 cell-cycle arrest and overrode RET-driven cell proliferation. Moreover, consistent with the marked in vivo efficacy of RET inhibition, the intratumoral c-Myc level was significantly decreased. In summary, SYHA1815 is a promising RETi for RET-aberrant cancer treatment that is currently in a phase I trial.

Discovery of 1,5-Dihydro-4H-imidazol-4-one Derivatives as Potent, Selective Antagonists of CXC Chemokine Receptor 2.

CXC chemokine receptors 1 (CXCR1) and 2 (CXCR2) have been demonstrated to have critical roles in cancer metastasis. Because they share high homology sequences, it is still unclear how to design selective CXCR1 or CXCR2 antagonists. Based on a pharmacophore model we built, compound 2 bearing a 1,5-dihydro-4H-imidazol-4-one scaffold was identified as a selective CXCR2 antagonist with a low CXCR1 antagonism preference. Further optimization and structure-activity relationship studies led to compound C5 that overcame the disadvantages of compound 2 and performed with higher selectivity. It showed excellent oral bioavailability and in vitro anticancer metastasis activity. Further dynamic simulation of the molecular protein complex showed that the amino acid residue K320 of CXCR2 contributed most to the selectivity of C5. This study provides important clues for the design of new CXCR2 selective antagonists, and C5 can be a molecular tool for investigating the difference in the biological function of CXCR1 and CXCR2.

DGAT1 inhibitors protect pancreatic ß-cells from palmitic acid-induced apoptosis.

Previous studies demonstrated that prolonged exposure to elevated levels of free fatty acids (FFA), especially saturated fatty acids, could lead to pancreatic ß-cell apoptosis, which plays an important role in the progression of type 2 diabetes (T2D). Diacylglycerol acyltransferase 1 (DGAT1), an enzyme that catalyzes the final step of triglyceride (TG) synthesis, has been reported as a novel target for the treatment of multiple metabolic diseases. In this study we evaluated the potential beneficial effects of DGAT1 inhibitors on pancreatic ß-cells, and further verified their antidiabetic effects in db/db mice. We showed that DGAT1 inhibitors (4a and LCQ908) at the concentration of 1 µM significantly ameliorated palmitic acid (PA)-induced apoptosis in MIN6 pancreatic ß-cells and primary cultured mouse islets; oral administration of a DGAT1 inhibitor (4a) (100 mg/kg) for 4 weeks significantly reduced the apoptosis of pancreatic islets in db/db mice. Meanwhile, 4a administration significantly decreased fasting blood glucose and TG levels, and improved glucose tolerance and insulin tolerance in db/db mice. Furthermore, we revealed that pretreatment with 4a (1 µM) significantly alleviated PA-induced intracellular lipid accumulation, endoplasmic reticulum (ER) stress, and proinflammatory responses in MIN6 cells, which might contribute to the protective effects of DGAT1 inhibitors on pancreatic ß-cells. These findings provided a better understanding of the antidiabetic effects of DGAT1 inhibitors.

GPR52 Antagonist Reduces Huntingtin Levels and Ameliorates Huntington's Disease-Related Phenotypes.

GPR52 is an orphan G protein-coupled receptor (GPCR) that has been recently implicated as a potential drug target of Huntington's disease (HD), an incurable monogenic neurodegenerative disorder. In this research, we found that striatal knockdown of GPR52 reduces mHTT levels in adult HdhQ140 mice, validating GPR52 as an HD target. In addition, we discovered a highly potent and specific GPR52 antagonist Comp-43 with an IC50 value of 0.63 µM by a structure-activity relationship (SAR) study. Further studies showed that Comp-43 reduces mHTT levels by targeting GPR52 and promotes survival of mouse primary striatal neurons. Moreover, in vivo study showed that Comp-43 not only reduces mHTT levels but also rescues HD-related phenotypes in HdhQ140 mice. Taken together, our study confirms that inhibition of GPR52 is a promising strategy for HD therapy, and the GPR52 antagonist Comp-43 might serve as a lead compound for further investigation.