Targeting EGFR degradation by autophagosome degraders.

Several generations of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors have been developed for the treatment of non-small cell lung cancer (NSCLC) in clinic. However, emerging drug resistance mediated by new EGFR mutations or activations by pass, leads to malignant progression of NSCLC. Proteolysis targeting chimeras (PROTACs) have been utilized to overcome the drug resistance acquired by mutant EGFR, newly potent and selective degraders are still need to be developed for clinical applications. Herein, we developed autophagosome-tethering compounds (ATTECs) in which EGFR can be anchored to microtubule-associated protein-1 light chain-3B (LC3B) on the autophagosome with the assistance of the LC3 ligand GW5074. A series of EGFR-ATTECs have been designed and synthesized. Biological evaluations showed that these compounds could degrade EGFR and exhibited moderate inhibitory effects on certain NSCLC cell lines. The ATTEC 12c potently induced the degradation of EGFR with a DC50 value of 0.98 µM and a Dmax value of 81% in HCC827 cells. Mechanistic exploration revealed that the lysosomal pathway was mainly involved in this degradation. Compound 12c also exhibited promising inhibitory activity, as well as degradation efficiency in vivo. Our study highlights that EGFR-ATTECs could be developed as a new expandable EGFR degradation tool and also reveals a novel potential therapeutic strategy to prevent drug resistance acquired EGFR mutations.

Discovery of LHF418 as a new potent SOS1 PROTAC degrader.

Son of sevenless homolog 1 (SOS1) plays a pivotal role as a molecular switch in the conversion of GDP-bound inactive KRAS to its active GTP-bound form, making SOS1 a promising therapeutic target for KRAS-driven cancers. While the most advanced SOS1 inhibitor has processed to phase I clinical trial, the exploration of novel SOS1 targeting strategies with distinct modes of action remains required. By employing proteolysis targeting chimera (PROTAC) technology, we obtained a series of new SOS1 degraders. The representative compound LHF418 potently induced SOS1 degradation with a DC50 value of 209.4 nM and a Dmax value of over 80 %. Mechanistic studies have illuminated that compound LHF418 induced the formation of ternary complex involving SOS1-PROTAC-cereblon (CRBN) and triggered SOS1 protein degradation in a CRBN- and proteasome-dependent manner. In addition, compound LHF418 effectively inhibited KRAS-RAF-ERK signalling, leading to the suppression of colony formation in KRAS-driven cancer cells. Overall, compound LHF418 represents a new lead compound in the developing novel and potent therapy for the treatment of KRAS-driven cancers.

Discovery of 5-aminopyrido[2,3-d]pyrimidin-7(8H)-one derivatives as new hematopoietic progenitor kinase 1 (HPK1) inhibitors.

Hematopoietic progenitor kinase 1 (HPK1) is a negative regulator of T-cell receptor signaling. While HPK1 is considered as a promising target for cancer immunotherapy, no small-molecule HPK1 inhibitors have been approved for cancer treatment. Herein, we report the discovery of a series of new HPK1 inhibitors with a 5-aminopyrido[2,3-d]pyrimidin-7(8H)-one scaffold. The most potent compound 9f inhibited HPK1 kinase activity with an IC50 of 0.32 nM in the time-resolved fluorescence resonance energy transfer (TR-FRET) assays, while displayed reasonable selectivity in a panel of 416 kinases. Cellular engagement of HPK1 by compound 9f was confirmed through the nano-bioluminescence resonance energy transfer (Nano-BRET) experiments. Compound 9f effectively reduced the phosphorylation of the downstream protein SLP-76 in primary peripheral blood mononuclear cells (PBMCs) and human T lymphocytic leukemia Jurkat cells. Compound 9f also enhanced the IL-2 and IFN-γ secretion in PBMCs. Furthermore, the binding mode of compound 9f with HPK1 was confirmed by the resolved cocrystal structure. Taken together, this study provides HPK1 inhibitors with a novel scaffold and clear binding mode for further development of HPK1-targeted therapeutic agents.

Development and validation of an interpretable model integrating multimodal information for improving ovarian cancer diagnosis.

Ovarian cancer, a group of heterogeneous diseases, presents with extensive characteristics with the highest mortality among gynecological malignancies. Accurate and early diagnosis of ovarian cancer is of great significance. Here, we present OvcaFinder, an interpretable model constructed from ultrasound images-based deep learning (DL) predictions, Ovarian-Adnexal Reporting and Data System scores from radiologists, and routine clinical variables. OvcaFinder outperforms the clinical model and the DL model with area under the curves (AUCs) of 0.978, and 0.947 in the internal and external test datasets, respectively. OvcaFinder assistance led to improved AUCs of radiologists and inter-reader agreement. The average AUCs were improved from 0.927 to 0.977 and from 0.904 to 0.941, and the false positive rates were decreased by 13.4% and 8.3% in the internal and external test datasets, respectively. This highlights the potential of OvcaFinder to improve the diagnostic accuracy, and consistency of radiologists in identifying ovarian cancer.

Access to 2,4-Disubstituted Pyrrole-Based Polymer with Long-Wavelength and Stimuli-Responsive Properties via Copper-Catalyzed [3+2] Polycycloaddition.

Pyrrole-based polymers (PBPs), a type of fascinating functional polymers, play a crucial role in materials science. However, efficient synthetic strategies of PBPs with diverse structures are mainly focused on conjugated polypyrroles and still remain challenging. Herein, an atom and step economy protocol is described to access various 2,4-disubstituted PBPs by in situ formation of pyrrole core structure via copper-catalyzed [3+2] polycycloaddition of dialkynones and diisocyanoacetates. A series of PBPs is prepared with high molecular weight (Mw up to 18 200 Da) and moderate to good yield (up to 87%), which possesses a fluorescent emission located in the green to yellow light region. Blending the PBPs with polyvinyl alcohol, the stretchable composite films exhibit a significant strengthening of the mechanical properties (tensile stress up to 59 MPa, elongation at break >400%) and an unprecedented stress-responsive luminescence enhancement that over fourfold fluorescent emission intensity is maintained upon stretching up to 100%. On the basis of computational studies, the unique photophysical and mechanical properties are attributed to the substitution of carbonyl chromophores on the pyrrole unit.

Discovery of LWY713 as a potent and selective FLT3 PROTAC degrader with in vivo activity against acute myeloid leukemia.

Fms-like tyrosine kinase 3 (FLT3) has been validated as a therapeutic target for acute myeloid leukemia (AML). While a number of FLT3 kinase inhibitors have been approved for AML treatment, the clinical data revealed that they cannot achieve complete and sustained suppression of FLT3 signaling at the tolerated dose. Here we report a series of new, potent and selective FLT3 proteolysis targeting chimera degraders. The optimal compound LWY713 potently induced the degradation of FLT3 with a DC50 value of 0.64 nM and a Dmax value of 94.8% in AML MV4-11 cells with FLT3-internal tandem duplication (ITD) mutation. Mechanistic studies demonstrated that LWY713 selectively induced FLT3 degradation in a cereblon- and proteasome-dependent manner. LWY713 potently inhibited FLT3 signaling, suppressed cell proliferation, and induced cell G0/G1-phase arrest and apoptosis in MV4-11 cells. Importantly, LWY713 displayed potent in vivo antitumor activity in MV4-11 xenograft models.

Discovery of a First-in-Class Degrader for the Lipid Kinase PIKfyve.

The phosphoinositide kinase PIKfyve has emerged as a new potential therapeutic target in various cancers. However, limited clinical progress has been achieved with PIKfyve inhibitors. Here, we report the discovery of a first-in-class PIKfyve degrader 12d (PIK5-12d) by employing the proteolysis-targeting chimera approach. PIK5-12d potently degraded PIKfyve protein with a DC50 value of 1.48 nM and a Dmax value of 97.7% in prostate cancer VCaP cells. Mechanistic studies revealed that it selectively induced PIKfyve degradation in a VHL- and proteasome-dependent manner. PIKfyve degradation by PIK5-12d caused massive cytoplasmic vacuolization and blocked autophagic flux in multiple prostate cancer cell lines. Importantly, PIK5-12d was more effective in suppressing the growth of prostate cancer cells than the parent inhibitor and exerted prolonged inhibition of downstream signaling. Further, intraperitoneal administration of PIK5-12d exhibited potent PIKfyve degradation and suppressed tumor proliferation in vivo. Overall, PIK5-12d is a valuable chemical tool for exploring PIKfyve-based targeted therapy.

Discovery of new Lenalidomide derivatives as potent and selective GSPT1 degraders.

G1 to S phase transition 1 (GSPT1) is the requisite release factor for the translation termination. GSPT1 is identified as an oncogenic driver of several types of cancer and considered to be a promising cancer therapeutic target. Although two selective GSPT1 degraders were advanced into clinical trials, neither of them has been approved for clinical use. Here we developed a series of new selective GSPT1 degraders, among which the optimal compound 9q potently induced degradation of GSPT1 with a DC50 of 35 nM in U937 cells, and showed good selectivity in the global proteomic profiling study. Mechanism studies revealed that compound 9q induced GSPT1 degradation through the ubiquitin-proteasome system. Consistent with its potent GSPT1 degradation activity, compound 9q displayed good antiproliferative activities against U937 cells, MOLT-4 cells, and MV4-11 cells, with IC50 values of 0.019 µM, 0.006 µM, and 0.027 µM, respectively. Compound 9q also dose-dependently induced G0/G1 phase arrest and apoptosis in U937 cells.

Discovery of AXL Degraders with Improved Potencies in Triple-Negative Breast Cancer (TNBC) Cells.

AXL kinase is heavily involved in tumorigenesis, metastasis, and drug resistance of many cancers, and several AXL inhibitors are in clinical investigations. Recent studies demonstrated that the N-terminal distal region of AXL plays more important roles in cell invasiveness than its C-terminal kinase domain. Therefore, degradation of AXL may present a novel superior therapeutic approach than the kinase inhibitor therapy. Herein, we report the discovery of a series of new AXL PROTAC degraders. One representative compound 6n potently depletes AXL with a DC50 value of 5 nM in MDA-MB-231 TNBC cells. It also demonstrates significantly improved potencies against the AXL signaling activation, cell proliferation, migration and invasion of TNBC cells comparing with the corresponding kinase inhibitor. Moreover, the compound exhibits promising therapeutic potential both in patient-derived organoids and a xenograft mouse model of MDA-MB-231 cells.

1-Methyl-3-((4-(quinolin-4-yloxy)phenyl)amino)-1H-pyrazole-4-carboxamide derivatives as new rearranged during Transfection (RET) kinase inhibitors capable of suppressing resistant mutants in solvent-front regions.

REarranged during Transfection (RET) is a validated target for anticancer drug discovery and two selective RET inhibitors were approved by US FDA in 2020. However, acquired resistance mediated by secondary mutations in the solvent-front region of the kinase (e.g. G810C/S/R) becomes a major challenge for selective RET inhibitor therapies. Herein, we report a structure-based design of 1-methyl-3-((4-(quinolin-4-yloxy)phenyl)amino)-1H-pyrazole-4-carboxamide derivatives as new RET kinase inhibitors which are capable of suppressing the RETG810 C/R resistant mutants. One of the representative compounds, 8q, potently suppressed wild-type RET kinase with an IC50 value of 13.7 nM. It also strongly inhibited the proliferation of BaF3 cells stably expressing various oncogenic fusions of RET kinase with solvent-front mutations, e.g. CCDC6-RETG810C, CCDC6-RETG810R, KIF5B-RETG810C and KIF5B-RETG810R, with IC50 values of 15.4, 53.2, 54.2 and 120.0 nM, respectively. Furthermore, 8q dose-dependently inhibited the activation of RET and downstream signals and obviously triggered apoptosis in Ba/F3-CCDC6-RETG810 C/R cells. The compound also exhibited significant anti-tumor efficacy with a tumor growth inhibition (TGI) value of 66.9% at 30 mg/kg/day via i. p. in a Ba/F3-CCDC6-RETG810C xenograft mouse model. Compound 8q may be utilized as a lead compound for drug discovery combating acquired resistance against selective RET inhibitor therapies.

Discovery of the First Examples of Threonine Tyrosine Kinase PROTAC Degraders.

The first examples of threonine tyrosine kinase (TTK) PROTACs were designed and synthesized. Two of the most potent molecules, 8e and 8j, demonstrated strong TTK degradation in COLO-205 human colorectal cancer cells with DC50 values of 1.7 and 3.1 nM, respectively. Proteasome-mediated degradation by the compounds could last for approximately 8 h after washout. The degraders 8e and 8j demonstrated improved antiproliferative activities comparing with the structurally similar inhibitor counterparts 8q and 8r. Degraders 8e and 8j also demonstrated reasonable PK profiles and exhibited potent target degradation and in vivo anticancer efficacy in a xenograft mouse model of COLO-205 human colorectal cancer cells upon i.p. administration.

Copper(i)-catalyzed asymmetric intramolecular C-arylation with ureas as the additives: highly enantioselective formation of spirooxindoles.

A cooperative catalytic strategy is developed for a copper-catalyzed asymmetric intramolecular C-arylation reaction with ureas as the co-catalysts. By forming hydrogen bonds with 1,3-dicarbonyl structures, ureas can activate the substrates, stabilize the carbanion intermediates and the products, and fix the syn-configurations of 1,3-dicarbonyl structures. They help enhance the reactivity, prevent side reactions and improve the enantioselectivities.

Transition metal-free approach to azafluoranthene scaffolds by aldol condensation/[1+2+3] annulation tandem reaction of isocyanoacetates with 8-(alkynyl)-1-naphthaldehydes.

A transition metal-free aldol condensation/[1+2+3] annulation reaction of isocyanoacetates with 8-(alkynyl)-1-naphthaldehydes has been developed for the general synthesis of azafluoranthenes. This domino reaction enables successive formation of three new bonds and two rings from readily accessible starting materials in a single operation. Furthermore, this methodology can also be utilized to construct chromeno[4,3-c]pyridines and benzo[c][2,6]naphthyridines in moderate yields.

Metal-free tandem reactions of 2-iodoaryl ynones with sodium azide for the synthesis of benzoisoxazole containing 1,2,3-triazoles.

A metal-free approach has been developed for the synthesis of benzo[c]isoxazole (anthranils) containing 1,2,3-triazoles. The reaction proceeded efficiently through a [3 + 2] azide-alkyne cycloaddition, SNAr azidation and denitrogenative cyclization sequence. The metal-free protocol enabled effective construction of one N-O and three C-N bonds in one pot. In addition, the synthetic utility of the current methodology was further demonstrated by late stage modification of the obtained products.

Conductive Antibacterial Hemostatic Multifunctional Scaffolds Based on Ti3C2Tx MXene Nanosheets for Promoting Multidrug-Resistant Bacteria-Infected Wound Healing.

Chronic bacterial-infected wound healing/skin regeneration remains a challenge due to drug resistance and the poor quality of wound repair. The ideal strategy is combating bacterial infection, while facilitating satisfactory wound healing. However, the reported strategy hardly achieves these two goals simultaneously without the help of antibiotics or bioactive molecules. In this work, a two-dimensional (2D) Ti3C2Tx MXene with excellent conductivity, biocompatibility, and antibacterial ability was applied in developing multifunctional scaffolds (HPEM) for methicillin-resistant Staphylococcus aureus (MRSA)-infected wound healing. HPEM scaffolds were fabricated by the reaction between the poly(glycerol-ethylenimine), Ti3C2Tx MXene@polydopamine (MXene@PDA) nanosheets, and oxidized hyaluronic acid (HCHO). HPEM scaffolds presented multifunctional properties containing self-healing behavior, electrical conductivity, tissue-adhesive feature, antibacterial activity especially for MRSA resistant to many commonly used antibiotics (antibacterial efficiency was 99.03%), and rapid hemostatic capability. HPEM scaffolds enhanced the proliferation of normal skin cells with negligible toxicity. Additionally, HPEM scaffolds obviously accelerated the MRSA-infected wound healing (wound closure ratio was 96.31%) by efficient anti-inflammation effects, promoting cell proliferation, and the angiogenic process, stimulating granulation tissue formation, collagen deposition, vascular endothelial differentiation, and angiogenesis. This study indicates the important role of multifunctional 2D MXene@PDA nanosheets in infected wound healing. HPEM scaffolds with multifunctional properties provide a potential strategy for MRSA-infected wound healing/skin regeneration.

Metal-Free Tandem Approach for Triazole-Fused Diazepinone Scaffolds via [3 + 2]Cycloaddition/C-N Coupling Reaction.

A novel metal-free, efficient cascade reaction has been developed to construct 1,2,3-triazole-fused 1,4-diazepinone skeletons. Mechanism investigation indicated that sodium azide has not only served as a 1,3-dipoles synthon in [3 + 2] cycloaddition but also prompted C-N bond formation. Furthermore, the potential utility of this protocol was demonstrated by scale-up synthesis of 1,2,3-triazole-fused diazepinone derivatives and the derivatization of them.

Biodegradable conductive multifunctional branched poly(glycerol-amino acid)-based scaffolds for tumor/infection-impaired skin multimodal therapy.

The tumor/infection-impaired skin regeneration is still a challenge and the single modal therapy strategy is usually inefficient. Herein, a multimodal tumor therapy and antiinfection method based on the conductive multifunctional poly(glycerol-amino acid)-based scaffolds is reported. The multifunctional conductive scaffolds were formed through the crosslinking between branched poly(glycerol-amino acid), polypyrrole@polydopamine (PPy@PDA) nanoparticles and aldehyde F127 (PGFP scaffolds). PGFP scaffolds possessed controlled electrical conductivity, skin-adhesive behavior, broad-spectrum antibacterial activity, photothermal-responsive drug release and good cytocompatibility. Thus, PGFP scaffolds demonstrated the significant photothermo-chemo tumor and multidrug resistant infection therapy in vitro and in vivo, while promoting granulation tissue formation, collagen deposition, vascular endothelial differentiation and accelerated skin regeneration. This work also firstly demonstrated the important role of multifunctional conductive PPy@PDA nanoparticles in tumor/infection-impaired skin multimodal therapy. This study suggests that efficient multimodal therapy on diseased-impaired skin could be achieved through optimizing the structure and multifunctional properties of biomaterials.

Identification and Development of 1,4-Diaryl-1,2,3-triazolo-Based Ureas as Novel FLT3 Inhibitors.

A class of 1,4-diaryl-1,2,3-triazolo-based ureas were synthesized and developed as novel FLT3 inhibitors. The representative compound 28 strongly inhibited FLT3-ITD kinase (IC50 = 32.8 nM) and isogenic BaF3-FLT3-ITD cell (GI50 = 0.6 nM). It exhibited potent inhibition against FLT3-ITD positive MV4-11 (GI50 = 3.0 nM) and MOLM-13 (GI50 = 5.9 nM) cell lines and high selectivity over FLT3-WT cell lines. It also displayed good pharmacokinetics properties and demonstrated promising oral in vivo efficacy in a MV4-11 cell xenografted mouse model. It might be a potent lead compound for further development to treat FLT3-ITD driven acute myloid leukemia.

A Disulfonimide Catalyst for Highly Enantioselective Mukaiyama-Mannich Reaction.

A new BINOL-derived chiral disulfonimide has been developed by introducing 4-methyl-3,5-dinitrophenyl substituents at its 3- and 3'-positions. This chiral disulfonimide catalyst displays high catalytic efficacy toward the asymmetric Mukaiyama-Mannich reaction of imines with ketene silyl acetals leading to ß-amino acid esters in good yields (up to 99%) with high diastereoselectivities (syn/anti up to 97:3) and enantioselectivities (up to 98% ee). The long-standing problem of the chiral phosphoric acid-catalyzed asymmetric Mukaiyama-Mannich reaction that requires a 2-hydroxyphenyl moiety was solved by this disulfonimide catalyst.

A Powerful Chiral Phosphoric Acid Catalyst for Enantioselective Mukaiyama-Mannich Reactions.

A new BINOL-derived chiral phosphoric acid bearing 2,4,6-trimethyl-3,5-dinitrophenyl substituents at the 3,3'-positions was developed. The utility of this chiral phosphoric acid is demonstrated by a highly enantioselective (ee up to >99 %) and diastereoselective (syn/anti up to >99:1) asymmetric Mukaiyama-Mannich reaction of imines with a wide range of ketene silyl acetals. Moreover, this method was successfully applied to the construction of vicinal tertiary and quaternary stereogenic centers with excellent diastereo- and enantioselectivity. Significantly, BINOL-derived N-triflyl phosphoramide constitutes a complementary catalyst system that allows the title reaction to be applied to more challenging imines without an N-(2-hydroxyphenyl) moiety.