Targeting EGFR with molecular degraders as a promising strategy to overcome resistance to EGFR inhibitors.

Abnormal activation of EGFR is often associated with various malignant tumors, making it an important target for antitumor therapy. However, traditional targeted inhibitors have several limitations, such as drug resistance and side effects. Many studies have focused on the development of EGFR degraders to overcome this resistance and enhance the therapeutic effect on tumors. Proteolysis targeting chimeras (PROTAC) and Lysosome-based degradation techniques have made significant progress in degrading EGFR. This review provides a summary of the structural and function of EGFR, the resistance, particularly the research progress and activity of EGFR degraders via the proteasome and lysosome. Furthermore, this review aims to provide insights for the development of the novel EGFR degraders.

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Synthesis and Biological Activity of Tetracyclic Dispiro Core Derivatives of Natural Products Dispirocochlearoids A-C.

Natural products dispirocochlearoids A-C, which are meroterpenoids derived from Ganoderma fungi, feature a 6/6/5/6/6/6 ring system and exhibit selective COX-2 inhibitory activity. Herein, the concise total synthesis of the tetracyclic core structure of dispirocochlearoids A-C was achieved through an aldol reaction/cyclization/deprotection/cyclization cascade sequence. A series of simplified tetracyclic analogues was successfully constructed and their anti-inflammatory activity was further explored, with several tetracyclic analogues (such as compound 8ab) exhibiting strong inhibitory activity against IL-1ß expression in lipopolysaccharide-stimulated bone marrow-derived macrophage cells (IC50 = 2.8 µM).

Design, Synthesis, and Biological Evaluation of Dual Inhibitors of EGFRL858R/T790M/ACK1 to Overcome Osimertinib Resistance in Nonsmall Cell Lung Cancers.

Activation of the alternative pathways and abnormal signaling transduction are frequently observed in third-generation EGFR-TKIs (epidermal growth factor receptor tyrosine kinase inhibitors)-resistant patients. Wherein, hyperphosphorylation of ACK1 contributes to EGFR-TKIs acquired resistance. Dual inhibition of EGFRL858R/T790M and ACK1 might improve therapeutic efficacy and overcome resistance in lung cancers treatment. Here, we identified a EGFRL858R/T790M/ACK1 dual-targeting compound 21a with aminoquinazoline scaffold, which showed excellent inhibitory activities against EGFRL858R/T790M (IC50 = 23 nM) and ACK1 (IC50 = 263 nM). The cocrystal and docking analysis showed that 21a occupied the ATP binding pockets of EGFRL858R/T790M and ACK1. Moreover, 21a showed potent antiproliferative activities against the H1975 cells, MCF-7 cells and osimertinib-resistant cells AZDR. Further, 21a showed significant antitumor effects and good safety in ADZR xenograft-bearing mice. Taken together, 21a was a potent dual inhibitor of EGFRL858R/T790M/ACK1, which is deserved as a potential lead for overcoming acquired resistance to osimertinib during the EGFR-targeted therapy.

Design, Synthesis, and Antitumor Activity of Potent and Selective EGFR L858R/T790M Inhibitors and Identification of a Combination Therapy to Overcome Acquired Resistance in Models of Non-small-cell Lung Cancer.

Epidermal growth factor receptor (EGFR) is one of the most studied drug targets for the treatment of non-small-cell lung cancer (NSCLC). Here, we report the identification, structure optimization, and structure-activity relationship studies of quinazoline derivatives as novel selective EGFR L858R/T790M inhibitors. The most promising compound, 28f, exhibited strong inhibitory activity against EGFR L858R/T790M (IC50 = 3.5 nM) and greater than 368-fold selectivity over EGFR WT (IC50 = 1290 nM), a 6.7-fold improvement over osimertinib. Furthermore, 28f effectively inhibited downstream signaling pathways and induced apoptosis in mutant cells. In the H1975 xenograft in vivo model, 28f exhibited a good tumor suppressive effect. Furthermore, the combination of 28f with the ACK1 inhibitor dasatinib produced synergistic antiproliferative efficacy with 28f in 28f-resistant cells and in vivo. In conclusion,28f could become a candidate drug for the treatment of NSCLC, and the combination of 28f and dasatinib is expected to overcome EGFR resistance.

A sulfhydryl blocking reagent BT-4 sensitizes cisplatin-based micelle prodrugs for efficient treatment of breast cancer.

Detoxification of glutathione (GSH) and insufficient cellular uptake of cisplatin (CDDP) severely compromised the therapeutic efficacy of CDDP. Here, a nano-delivery system (BT-4@PtPPNPs) for CDDP prodrug (C16-Pt(Ⅳ)-PEG) based on a novel sulfhydryl blocking reagent methyl 2-(methylsulfonyl) benzothiazole-6-carboxylate (BT-4) was developed. On the one hand, BT-4 can deplete GSH in tumor cells by directly interacting with reactive sulfhydryl group on GSH, thereby increasing the cytotoxicity of CDDP. On the other hand, the CDDP prodrug carrier C16-Pt(IV)-PEG can promote the distribution of CDDP in tumors, reduce the probability of unexpected inactivation of CDDP, and reduce the content of GSH in tumor cells during the conversion to CDDP, thereby making CDDP more effective for treatment. The results showed that the optimized BT-4@PtPPNPs with a small particle size (130 nm) exhibited notable cytotoxicity and apoptosis of 4T1 cells. BT-4@PtPPNPs not only significantly improved the uptake of drugs by tumor cells, but also rapidly targeted and accumulated in the tumors for a long time. Moreover, in vivo efficacy studies showed that BT-4@PtPPNPs could effectively inhibit tumor growth, inhibiting 60.85 % of tumors in a 4T1 breast cancer mice model, showing superior antitumor activity, which can be attributed to GSH-triggered CDDP tolerance reversal. Overall, this study provides an attractive and simple strategy to combine novel sulfhydryl blockers and CDDP prodrugs to potentiate the efficacy of CDDP in breast cancer.

Emerging strategies to overcome resistance to third-generation EGFR inhibitors.

Epidermal growth factor receptor (EGFR), the receptor for members of the epidermal growth factor family, regulates cell proliferation and signal transduction; moreover, EGFR is related to the inhibition of tumor cell proliferation, angiogenesis, invasion, metastasis, and apoptosis. Therefore, EGFR has become an important target for the treatment of cancer, including non-small cell lung cancer, head and neck cancer, breast cancer, glioma, cervical cancer, and bladder cancer. First- to third-generation EGFR inhibitors have shown considerable efficacy and have significantly improved disease prognosis. However, most patients develop drug resistance after treatment. The challenge of overcoming intrinsic and acquired resistance in primary and recurrent cancer mediated by EGFR mutations is thus driving the search for alternative strategies in the design of new therapeutic agents. In view of resistance to third-generation inhibitors, understanding the intricate mechanisms of resistance will offer insight for the development of more advanced targeted therapies. In this review, we discuss the molecular mechanisms of resistance to third-generation EGFR inhibitors and review recent strategies for overcoming resistance, new challenges, and future development directions.

Development of small molecule extracellular signal-regulated kinases (ERKs) inhibitors for cancer therapy.

The mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase 1/2 (ERK1/2) signaling pathway is widely activated by a variety of extracellular stimuli, and its dysregulation is associated with the proliferation, invasion, and migration of cancer cells. ERK1/2 is located at the distal end of this pathway and rarely undergoes mutations, making it an attractive target for anticancer drug development. Currently, an increasing number of ERK1/2 inhibitors have been designed and synthesized for antitumor therapy, among which representative compounds have entered clinical trials. When ERK1/2 signal transduction is eliminated, ERK5 may provide a bypass route to rescue proliferation, and weaken the potency of ERK1/2 inhibitors. Therefore, drug research targeting ERK5 or based on the compensatory mechanism of ERK5 for ERK1/2 opens up a new way for oncotherapy. This review provides an overview of the physiological and biological functions of ERKs, focuses on the structure-activity relationships of small molecule inhibitors targeting ERKs, with a view to providing guidance for future drug design and optimization, and discusses the potential therapeutic strategies to overcome drug resistance.

Unraveling the Design and Discovery of c-Jun N-Terminal Kinase Inhibitors and Their Therapeutic Potential in Human Diseases.

c-Jun N-terminal kinases (JNKs), members of the mitogen-activated protein kinase (MAPK) family, are encoded by three genes: jnk1, jnk2, and jnk3. JNKs are involved in the pathogenesis and development of many diseases, such as neurodegenerative diseases, inflammation, and cancers. Therefore, JNKs have become important therapeutic targets. Many JNK inhibitors have been discovered, and some have been introduced into clinical trials. However, the study of isoform-selective JNK inhibitors is still a challenging task. To further develop novel JNK inhibitors with clinical value, a comprehensive understanding of JNKs and their corresponding inhibitors is required. In this Perspective, we introduced the JNK signaling pathways and reviewed different chemical types of JNK inhibitors, focusing on their structure-activity relationships and biological activities. The challenges and strategies for the development of JNK inhibitors are also discussed. It is hoped that this Perspective will provide valuable references for the development of novel selective JNK inhibitors.

Targeting Lysosomal Degradation Pathways: New Strategies and Techniques for Drug Discovery.

A series of tools for targeted protein degradation are inspiring scientists to develop new drugs with advantages over traditional small-molecule drugs. Among these tools, proteolysis-targeting chimeras (PROTACs) are most representative of the technology based on proteasomes. However, the proteasome has little degradation effect on certain macromolecular proteins or aggregates, extracellular proteins, and organelles, which limits the application of PROTACs. Additionally, lysosomes play an important role in protein degradation. Therefore, lysosome-induced protein degradation drugs can directly regulate protein levels in vivo, achieve the goal of treating diseases, and provide new strategies for drug discovery. Lysosome-based degradation technology has the potential for clinical translation. In this review, strategies targeting lysosomal pathways and lysosome-based degradation techniques are summarized. In addition, lysosome-based degrading drugs are described, and the advantages and challenges are listed. Our efforts will certainly promote the design, discovery, and clinical application of drugs associated with this technology.

Targeting autophagy using small-molecule compounds to improve potential therapy of Parkinson's disease.

Parkinson's disease (PD), known as one of the most universal neurodegenerative diseases, is a serious threat to the health of the elderly. The current treatment has been demonstrated to relieve symptoms, and the discovery of new small-molecule compounds has been regarded as a promising strategy. Of note, the homeostasis of the autolysosome pathway (ALP) is closely associated with PD, and impaired autophagy may cause the death of neurons and thereby accelerating the progress of PD. Thus, pharmacological targeting autophagy with small-molecule compounds has been drawn a rising attention so far. In this review, we focus on summarizing several autophagy-associated targets, such as AMPK, mTORC1, ULK1, IMPase, LRRK2, beclin-1, TFEB, GCase, ERRα, C-Abelson, and as well as their relevant small-molecule compounds in PD models, which will shed light on a clue on exploiting more potential targeted small-molecule drugs tracking PD treatment in the near future.

Small Molecules Targeting Activated Cdc42-Associated Kinase 1 (ACK1/TNK2) for the Treatment of Cancers.

Activated Cdc42-associated kinase 1 (ACK1/TNK2) is a nonreceptor tyrosine kinase with a unique structure. It not only can act as an activated transmembrane effector of receptor tyrosine kinases (RTKs) to transmit various RTK signals but also can play a corresponding role in epigenetic regulation. A number of studies have shown that ACK1 is a carcinogenic factor. Blockage of ACK1 has been proven to be able to inhibit cancer cell survival, proliferation, migration, and radiation resistance. Thus, ACK1 is a promising potential antitumor target. To date, despite many efforts to develop ACK1 inhibitors, no specific small molecule inhibitors have entered clinical trials. This Perspective provides an overview of the structural features, biological functions, and association with diseases of ACK1 and in vitro and in vivo activities, selectivity, and therapeutic potential of small molecule ACK1 inhibitors with different chemotypes.

Developing potent LC3-targeting AUTAC tools for protein degradation with selective autophagy.

Autophagy-based protein degradation is emerging as a promising technology for anti-diseases and innovative drug discovery. Here, we demonstrate a novel type of autophagy-targeting chimera (AUTAC) to degrade protein by targeting autophagy key protein LC3. The best compound 10f powerfully degraded BRD4 protein through the autophagy pathway and exhibited good anti-proliferative activity in multiple tumor cells, providing a powerful toolbox for medicinal chemists to study disease-related targets with autophagy-based degradation.

Asymmetric organocatalytic multicomponent reactions for efficient construction of bicyclic compounds bearing bisacetal and isoxazolidine moieties.

An organocatalytic multicomponent reaction of N-protected hydroxylamines, acrylaldehyde and acetal-containing enones was developed. Bisacetal-containing bicyclic isoxazolidine derivatives bearing four continuous stereocenters were formed with excellent stereoselectivities. A plausible reaction pathway was proposed based on 18O-labeling control experiments.

Asymmetric Organocatalytic Sequential Reaction of Structurally Complex Cyclic Hemiacetals and Functionalized Nitro-olefins To Synthesize Diverse Heterocycles.

Structurally complex cyclic hemiacetals bearing a racemic tetrasubstituted stereocenter have been prepared in a concise manner and were successfully used in an organocatalytic enantioselective sequence to react with functionalized nitro-olefins, providing bicyclic acetal-containing compounds as two separable epimers with excellent stereoselectivity. The reaction showed broad substrate scope, with respect to the starting hemiacetals. Moreover, this protocol allows the synthetic transformation of the products to various interesting heterocyclic compounds with substantial structural diversity and broad functionality.