LIN28-Targeting Chromenopyrazoles and Tetrahydroquinolines Induced Cellular Morphological Changes and Showed High Biosimilarity with BRD PROTACs.

The probing of small molecules with heterocyclic scaffolds covering unexplored chemical space and the evaluation of their biological relevance are essential parts of forward chemical genetics approaches and for the development of potential small-molecule therapeutics. In this study, we profiled sets of chromenopyrazoles (CMPs) and tetrahydroquinolines (THQs), originally developed to target the protein-RNA interaction of LIN28-let-7, in a cell painting assay (CPA) measuring cellular morphological changes. Selected LIN28-inactive CMPs and THQs induced cellular morphological changes to different extents. The most CPA-active CMPs 2 and 3 exhibited high bio-similarity with the LCH and BET clusters, while the most CPA-active THQs 13 and 20 indicated a mechanism of action beyond the currently established biosimilarity clusters. Overall, this work demonstrated that CPA is useful in revealing "hidden" biological targets and mechanisms of action for biologically inactive small molecules, which are CMPs and THQs targeting the RNA-binding protein LIN28 in this case, evaluated in target-based strategies. When compared with annotated reference compounds, CMP 3 exhibited a high biosimilarity with the dual BRD7/9 degrading PROTAC VZ185, suggesting that CPA could potentially function as a new phenotypic approach to identify degrader molecules.

Rift Valley fever virus coordinates the assembly of a programmable E3 ligase to promote viral replication.

Viruses encode strategies to degrade cellular proteins to promote infection and pathogenesis. Here, we revealed that the non-structural protein NSs of Rift Valley fever virus forms a filamentous E3 ligase to trigger efficient degradation of targeted proteins. Reconstitution in vitro and cryoelectron microscopy analysis with the 2.9-Å resolution revealed that NSs forms right-handed helical fibrils. The NSs filamentous oligomers associate with the cellular FBXO3 to form a remodeled E3 ligase. The NSs-FBXO3 E3 ligase targets the cellular TFIIH complex through the NSs-P62 interaction, leading to ubiquitination and proteasome-dependent degradation of the TFIIH complex. NSs-FBXO3-triggered TFIIH complex degradation resulted in robust inhibition of antiviral immunity and promoted viral pathogenesis in vivo. Furthermore, it is demonstrated that NSs can be programmed to target additional proteins for proteasome-dependent degradation, serving as a versatile targeted protein degrader. These results showed that a virulence factor forms a filamentous and programmable degradation machinery to induce organized degradation of cellular proteins to promote viral infection.

Opportunities and challenges for targeting HPK1 in cancer immunotherapy.

Hematopoietic Progenitor Kinase 1 (HPK1, also known as MAP4K1) is a hematopoiesis-specific serine/threonine kinase that belongs to the MAP4K family of Ste20-related protein kinases. HPK1 has been identified as a negative regulator of T-cell receptor signaling. Recent studies have indicated that the inhibition or knockout of HPK1 kinase function can effectively alleviate T cell exhaustion, enhance T cell functionality, and improve the therapeutic efficacy of tumor immunotherapy. In recent years, small molecule chemical drugs targeting HPK1 have made significant progress and have become a hot topic in the research and development of tumor immunotherapy drugs. However, the advancement of small molecule drugs that target HPK1 is hindered by various challenges, including the limited selectivity, insufficient immune stimulation, and the ambiguity surrounding role of non-kinase scaffold functions of HPK1 in tumor immune responses. This review briefly describes the biological structure of HPK1 and its related signaling pathways in tumor immunity, systematically discusses the latest research progress in small molecule chemical drugs targeting HPK1. Finally, we summarize and prospect the opportunities and challenges in the drug development of small molecule chemical drugs targeting HPK1 in tumor immunity.

Powering up targeted protein degradation through active and passive tumour-targeting strategies: Current and future scopes.

Targeted protein degradation (TPD) has emerged as a prominent and vital strategy for therapeutic intervention of cancers and other diseases. One such approach involves the exploration of proteolysis targeting chimeras (PROTACs) for the selective elimination of disease-causing proteins through the innate ubiquitin-proteasome pathway. Due to the unprecedented achievements of various PROTAC molecules in clinical trials, researchers have moved towards other physiological protein degradation approaches for the targeted degradation of abnormal proteins, including lysosome-targeting chimeras (LYTACs), autophagy-targeting chimeras (AUTACs), autophagosome-tethering compounds (ATTECs), molecular glue degraders, and other derivatives for their precise mode of action. Despite numerous advantages, these molecules face challenges in solubility, permeability, bioavailability, and potential off-target or on-target off-tissue effects. Thus, an urgent need arises to direct the action of these degrader molecules specifically against cancer cells, leaving the proteins of non-cancerous cells intact. Recent advancements in TPD have led to innovative delivery methods that ensure the degraders are delivered in a cell- or tissue-specific manner to achieve cell/tissue-selective degradation of target proteins. Such receptor-specific active delivery or nano-based passive delivery of the PROTACs could be achieved by conjugating them with targeting ligands (antibodies, aptamers, peptides, or small molecule ligands) or nano-based carriers. These techniques help to achieve precise delivery of PROTAC payloads to the target sites. Notably, the successful entry of a Degrader Antibody Conjugate (DAC), ORM-5029, into a phase 1 clinical trial underscores the therapeutic potential of these conjugates, including LYTAC-antibody conjugates (LACs) and aptamer-based targeted protein degraders. Further, using bispecific antibody-based degraders (AbTACs) and delivering the PROTAC pre-fused with E3 ligases provides a solution for cell type-specific protein degradation. Here, we highlighted the current advancements and challenges associated with developing new tumour-specific protein degrader approaches and summarized their potential as single agents or combination therapeutics for cancer.

Oral SERDs changing the scenery in hormone receptor positive breast cancer, a comprehensive review.

BACKGROUND: Primary and acquired endocrine resistance remains a major issue in the treatment of hormone receptor positive breast cancer. Acquired resistance often results from estrogen receptor 1 (ESR1) mutations leading to estrogen independent estrogen receptor activation. Selective estrogen receptor degraders (SERDs) induce degradation of this receptor, thereby overcoming this resistance. The intramuscular administration and modest efficacy of fulvestrant, the first SERD, triggered development of oral, more potent SERDs. This narrative review gives an overview of the current evidence regarding this new drug class. METHODS: Medline/PubMed and Embase database were screened using a systematic search strategy. We assessed the San Antonio Breast Cancer Symposium abstract reports, the European Society of Medical Oncology (ESMO) and American Society of Clinical Oncology (ASCO) meeting resources by applying the following terms: 'SERD', 'giredestrant', 'elacestrant', 'imlunestrant', 'amcenestrant', 'camizestrant' and 'rintodestrant'. CLINICALTRIALS: gov was consulted to include ongoing trials. RESULTS: The search retrieved 1191 articles. After screening, 108 articles were retained. In the phase 3 EMERALD trial, elacestrant demonstrated benefit in progression free survival (PFS) in second line metastatic disease in postmenopausal women or men, leading to Food and Drug Administration (FDA) and European Medicines Agency (EMA) approval for the ESR1 mutated population. This PFS advantage was more pronounced among patients who had priorly received at least 12 months of a cyclin-dependent kinases 4/6 inhibitor (CDK4/6i). In the phase 2 SERENA-2 trial, camizestrant improved PFS as second line treatment. However, trials of giredestrant and amcenestrant failed to show PFS benefit in second line metastatic setting. In the preoperative setting, several oral SERDs resulted in a significant reduction of tumoral proliferation. Furthermore, many trials are still in progress. CONCLUSION: Oral SERDs constitute an exciting new drug class. Ongoing and future research will further refine the role of these drugs next to standard endocrine treatments and targeted therapies.

Safety and clinical activity of BMS-986365 (CC-94676), a dual androgen receptor ligand-directed degrader and antagonist, in heavily pretreated patients with metastatic castration-resistant prostate cancer.

BACKGROUND: Metastatic castration-resistant prostate cancer (mCRPC) that progresses on androgen receptor pathway inhibitors (ARPIs) may continue to be driven by AR signaling. BMS-986365 is an orally administered ligand-directed degrader targeting the AR via a first-in-class dual mechanism of AR degradation and antagonism. CC-94676-PCA-001 (NCT04428788) is a phase 1 multicenter study of BMS-986365 in patients with progressive mCRPC. PATIENTS AND METHODS: Patients who progressed on androgen deprivation therapy, ≥ 1 ARPI, and taxane chemotherapy (unless declined/ineligible) were enrolled. The study included dose escalation (Part A) and expansion (Part B) of BMS-986365 up to 900 mg twice daily (BID). Primary objectives were safety, tolerability, and to define maximum tolerated dose (MTD) and/or recommended phase 2 dose (RP2D). Key secondary endpoints included decline in prostate-specific antigen ≥50% (PSA50) and radiographic progression-free survival (rPFS). RESULTS: Parts A and B enrolled 27 and 68 patients, respectively. In Part B, the median number of prior therapies was 4 (range 2-11). The most common treatment-related adverse events (TRAEs) were asymptomatic prolonged corrected QT interval (47%) and bradycardia (34%). Part A MTD was not reached and RP2D selection is ongoing. Across Part B three highest doses (400-900 mg BID, n = 60), PSA50 was 32% (n = 19), including 50% (n = 10/20) at 900 mg; median rPFS (95% CI) was 6.3 months (5.3-12.6), including 8.3 months (3.8-16.6) at 900 mg; and rPFS was longer in patients without versus with prior chemotherapy: 16.5 months (5.5-not evaluable) versus 5.5 months (2.7-8.3), respectively. Efficacy was observed in patients with AR ligand binding domain (LBD) WT or with AR LBD mutations. CONCLUSIONS: BMS-986365 was well tolerated, with a manageable safety profile, and demonstrated activity in heavily pretreated patients with potentially higher benefit in chemotherapy-naïve patients. These data show BMS-986365's potential to overcome resistance to current ARPIs, regardless of AR LBD mutation status.

PROTAC-mediated conditional degradation of the WRN helicase as a potential strategy for selective killing of cancer cells with microsatellite instability.

Multiple studies have demonstrated that cancer cells with microsatellite instability (MSI) are intolerant to loss of the Werner syndrome helicase (WRN), whereas microsatellite-stable (MSS) cancer cells are not. Therefore, WRN represents a promising new synthetic lethal target for developing drugs to treat cancers with MSI. Given the uncertainty of how effective inhibitors of WRN activity will prove in clinical trials, and the likelihood of tumours developing resistance to WRN inhibitors, alternative strategies for impeding WRN function are needed. Proteolysis-targeting chimeras (PROTACs) are heterobifunctional small molecules that target specific proteins for degradation. Here, we engineered the WRN locus so that the gene product is fused to a bromodomain (Bd)-tag, enabling conditional WRN degradation with the AGB-1 PROTAC specific for the Bd-tag. Our data revealed that WRN degradation is highly toxic in MSI but not MSS cell lines. In MSI cells, WRN degradation caused G2/M arrest, chromosome breakage and ATM kinase activation. We also describe a multi-colour cell-based platform for facile testing of selective toxicity in MSI versus MSS cell lines. Together, our data show that a degrader approach is a potentially powerful way of targeting WRN in MSI cancers and paves the way for the development of WRN-specific PROTAC compounds.

Translational modelling to predict human pharmacokinetics and pharmacodynamics of a Bruton's tyrosine kinase-targeted protein degrader BGB-16673.

BACKGROUND AND PURPOSE: Bifunctional small molecule degraders, which link the target protein with E3 ubiquitin ligase, could lead to the efficient degradation of the target protein. BGB-16673 is a Bruton's tyrosine kinase (BTK) degrader. A translational PK/PD modelling approach was used to predict the human BTK degradation of BGB-16673 from preclinical in vitro and in vivo data. EXPERIMENTAL APPROACH: A simplified mechanistic PK/PD model was used to establish the correlation between the in vitro and in vivo BTK degradation by BGB-16673 in a mouse model. Human and mouse species differences were compared using the parameters generated from in vitro human or mouse blood, and human or mouse serum spiked TMD-8 cells. Human PD was then predicted using the simplified mechanistic PK/PD model. KEY RESULTS: BGB-16673 showed potent BTK degradation in mouse whole blood, human whole blood, and TMD-8 tumour cells in vitro. Furthermore, BGB-16673 showed BTK degradation in a murine TMD-8 xenograft model in vivo. The PK/PD model predicted human PD and the observed BTK degradation in clinical studies both showed robust BTK degradation in blood and tumour at clinical dose range. CONCLUSION AND IMPLICATIONS: The presented simplified mechanistic model with reduced number of model parameters is practically easier to be applied to research projects compared with the full mechanistic model. It can be used as a tool to better understand the PK/PD behaviour for targeted protein degraders and increase the confidence when moving to the clinical stage.

Discovery of KW0113 as a First and Effective PROTAC Degrader of DNMT1 Protein.

DNA methyltransferase 1 (DNMT1) is an attractive therapeutic target for acute myelocytic leukemia (AML) and other malignancies. It has been reported that the genetic depletion of DNMT1 inhibited AML cell proliferation through reversing DNA methylation abnormalities. However, no DNMT1-targeted PROTAC degraders have been reported yet. Herein, a series of proteolysis-targeting chimera (PROTAC) degrader of DNMT1 based on dicyanopyridine scaffold and VHL E3 ubiquitin ligase ligand was developed. Among them, KW0113 (DC50 = 643/899 nM in MV4-11/MOLM-13 cells) exhibited optimal DNMT1 degradation. KW0113 induced DNMT1-selective degradation in a dose- and time-dependent manner through VHL engagement. Moreover, KW0113 inhibited AML cell growth by reversing promoter DNA hypermethylation and tumor-suppressor genes silencing. In conclusion, these findings proved the capability of PROTAC strategy for inducing DNMT1 degradation, demonstrated the therapeutic potential of DNMT1-targeted PROTACs. This work also provided a convenient chemical knockdown tool for DNMT1-related studies.

PROTAC based STING degrader attenuates acute colitis by inhibiting macrophage M1 polarization and intestinal epithelial cells pyroptosis mediated by STING-NLRP3 axis.

Inflammatory bowel diseases (IBDs) are chronic, relapsing, and inflammatory disorders of the gastrointestinal tract characterized by abnormal immune responses. Recently, STING has emerged as a promising therapeutic target for various autoinflammatory diseases. However, few STING-selective small molecules have been investigated as novel strategies for IBD. In this study, we sought to examine the effects of PROTAC-based STING degrader SP23 on acute colitis and explore its underlying mechanism. SP23 treatment notably alleviates dextran sulfate sodium (DSS)-induced colitis. Pharmacological degradation of STING significantly reduced the production of inflammatory cytokines, such as TNF-α, IL-1ß, and IL-6, and inhibited macrophage polarization towards the M1 type. Furthermore, SP23 administration decreased the loss of tight junction proteins, including ZO-1, occludin, and claudin-1, and downregulated STING and NLRP3 signaling pathways in intestinal inflammation. In vitro, STING activated NLRP3 inflammasome-mediated pyroptosis in intestinal epithelial cells, which could be abrogated by SP23 and STING siRNA intervention. In conclusion, these findings provide new evidence for STING as a novel therapeutic target for IBD, and reveal that hyperactivation of STING could exaggerate colitis by inducing NLRP3/Caspase-1/GSDMD axis mediated intestinal epithelial cells pyroptosis.

ER membrane remodeling by targeting RTN4 induces pyroptosis to facilitate antitumor immune.

Pyroptosis is an identified programmed cell death that has been highly linked to endoplasmic reticulum (ER) dynamics. However, the crucial proteins for modulating dynamic ER membrane curvature change that trigger pyroptosis are currently not well understood. In this study, a biotin-labeled chemical probe of potent pyroptosis inducer α-mangostin (α-MG) was synthesized. Through protein microarray analysis, reticulon-4 (RTN4/Nogo), a crucial regulator of ER membrane curvature, was identified as a target of α-MG. We observed that chemically induced proteasome degradation of RTN4 by α-MG through recruiting E3 ligase UBR5 significantly enhances the pyroptosis phenotype in cancer cells. Interestingly, the downregulation of RTN4 expression significantly facilitated a dynamic remodeling of ER membrane curvature through a transition from tubules to sheets, consequently leading to rapid fusion of the ER with the cell plasma membrane. In particular, the ER-to-plasma membrane fusion process is supported by the observed translocation of several crucial ER markers to the "bubble" structures of pyroptotic cells. Furthermore, α-MG-induced RTN4 knockdown leads to PKM2-dependent conventional caspase-3/GSDME cleavages for pyroptosis progression. In vivo, we observed that chemical or genetic RTN4 knockdown significantly inhibited cancer cells growth, which further exhibited an antitumor immune response with anti-PD-1. In translational research, RTN4 high expression was closely correlated with the tumor metastasis and death of patients. Taken together, RTN4 plays a fundamental role in inducing pyroptosis through the modulation of ER membrane curvature remodeling, thus representing a prospective druggable target for anticancer immunotherapy.

Inducing or enhancing protein-protein interaction to develop drugs: Molecular glues with various biological activity.

Over the past two decades, molecular glues (MGs) have gradually attracted the attention of the pharmaceutical community with the advent of MG degraders such as IMiDs and indisulam. Such molecules degrade the target protein by promoting the interaction between the target protein and E3 ligase. In addition, as a chemical inducer, MGs promote the dimerization of homologous proteins and heterologous proteins to form ternary complexes, which have great prospects in regulating biological activities. This review focuses on the application of MGs in the field of drug development including protein-protein interaction (PPI) stability and protein degradation. We thoroughly analyze the structure of various MGs and the interactions between MGs and various biologically active molecules, thus providing new perspectives for the development of PPI stabilizers and new degraders.

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.

[Box: see text].

Design, synthesis, anti-tumor activity and mechanism of novel PROTACs as degraders of PD-L1 and inhibitors of PD-1/PD-L1 interaction.

Currently, antibody drugs targeting programmed cell death ligand 1 (PD-L1) have achieved promising results in cancer treatment, while the development of small-molecule drugs lags behind. In this study, we designed and synthesized a series of PD-L1-degrading agents based on the PROTAC design principle, utilizing the PD-L1 inhibitor A56. Through systematic screening of ligands and linkers and investigating the structure-activity relationship of the degraders, we identified two highly active compounds, 9i and 9j. These compounds enhance levels of CD4+, CD8+, granzyme B, and perforin, demonstrating significant in vivo antitumor effects with a tumor growth inhibition (TGI) of up to 57.35 %. Both compounds facilitate the internalization of PD-L1 from the cell surface and promote its degradation through proteasomal and lysosomal pathways, while also maintaining inhibition of the PD-1/PD-L1 interaction. In summary, our findings provide a novel strategy and mechanism for developing biphenyl-based PROTAC antitumor drugs targeting and degrading PD-L1.

Elacestrant in the treatment landscape of ER-positive, HER2-negative, ESR1-mutated advanced breast cancer: a contemporary narrative review.

Introduction: Estrogen receptor-positive (ER+), human epidermal growth factor receptor 2-negative (HER2-) breast cancer with ESR1 mutations presents a significant therapeutic challenge due to its adaptive resistance mechanisms to chemotherapy, especially endocrine treatment. Elacestrant, a novel oral selective estrogen receptor degrader (SERD), has emerged as a promising agent in this treatment-resistant era. Method: A comprehensive search was conducted on pivotal clinical trials, including the RAD1901-005 Trial, EMERALD TRIAL, ELIPSE, and ELEVATE, focusing on their methodologies, patient populations, treatment regimens, and outcomes. Discussion: This narrative review describes the available preclinical and clinical evidence on elacestrant, focusing on its pharmacodynamics, pharmacokinetics, efficacy, and safety within the existing literature. Elacestrant has demonstrated excellent activity against ESR1 mutations associated with resistance to first-line endocrine therapies. Clinical trials have shown improved progression-free survival in patients with advanced ER+/HER2-, ESR1-mutated breast cancer. Safety profiles indicate a tolerable side effect spectrum consistent with other agents. Its oral bioavailability offers a convenient alternative to injectable SERDs, with potential implications for patient adherence and quality of life. The review also discusses the comparative efficacy of elacestrant relative to existing endocrine therapies and its possible use in combination regimens. Conclusion: Ongoing clinical trials assessing elacestrant and other SERDs will yield data that might aid clinicians in determining the optimal selection and order of endocrine treatment drugs for ER+ breast cancer. The integration of targeted and immunotherapeutic agents with traditional chemotherapy represents a pivotal shift in Breast Cancer treatment, moving towards more personalized and effective regimens.

Design, synthesis and biological evaluation of a novel PAK1 degrader for the treatment of triple negative breast cancer.

Triple-negative breast cancer is one of the most malignant subtypes in clinical practice, and it is urgent to find new therapies. The p21-activated kinase I (PAK1) has been considered to be an attractive therapeutic target for TNBC. In this study, we designed and synthesized a series of novel PROTAC PAK1 degraders by conjugating VHL or CRBN ligase ligands to PAK1 inhibitors which are connected by alkyl chains or PEG chains. The most promising compound, 19s, can significantly degrade PAK1 protein at concentrations as low as 0.1 µM, and achieves potent anti-proliferative activity with an IC50 value of 1.27 µM in MDA-MB-231 cells. Additionally, 19s exhibits potent anti-migration activity in vitro and induces rapid tumor regression in vivo. Collectively, these findings document that 19s is a potent and novel PAK1 degrader with promising potential for TNBC treatment.

UBX-390: A Novel Androgen Receptor Degrader for Therapeutic Intervention in Prostate Cancer.

The androgen receptor (AR) is an attractive target for treating prostate cancer, considering its role in the development and progression of localized and metastatic prostate cancer. The high global mortality burden of prostate cancer, despite medical treatments such as androgen deprivation or AR antagonist therapy, highlights the need to explore alternative strategies. One strategy involves the use of heterobifunctional degraders, also known as proteolysis-targeting chimeras, which are novel small-molecule therapeutics that inhibit amplified or mutated targets. Here, the study reports a novel cereblon-based AR degrader, UBX-390, and demonstrates its superior activity over established AR degraders, such as ARV-110 or ARCC-4, in prostate cancer cells under short- and long-term treatment conditions. UBX-390 suppresses chromatin binding and gene expression of AR and demonstrates substantial efficacy in the degradation of AR mutants in patients with treatment-resistant prostate cancer. UBX-390 is presented as an optimized AR degrader with remarkable potential for treating castration-resistant prostate cancer.

SIP-metagenomics reveals key drivers of rhizospheric Benzo[a]pyrene bioremediation via bioaugmentation with indigenous soil microbes.

Rhizoremediation and bioaugmentation have proven effective in promoting benzo[a]pyrene (BaP) degradation in contaminated soils. However, the mechanism underlying bioaugmented rhizospheric BaP degradation with native microbes is poorly understood. In this study, an indigenous BaP degrader (Stenotrophomonas BaP-1) isolated from petroleum-contaminated soil was introduced into ryegrass rhizosphere to investigate the relationship between indigenous degraders and rhizospheric BaP degradation. Stable isotope probing and 16S rRNA gene amplicon sequencing subsequently revealed 15 BaP degraders, 8 of which were directly associated with BaP degradation including Bradyrhizobium and Streptomyces. Bioaugmentation with strain BaP-1 significantly enhanced rhizospheric BaP degradation and shaped the microbial community structure. A correlation of BaP degraders, BaP degradation efficiency, and functional genes identified active degraders and genes encoding polycyclic aromatic hydrocarbon-ring hydroxylating dioxygenase (PAH-RHD) genes as the primary drivers of rhizospheric BaP degradation. Furthermore, strain BaP-1 was shown to not only engage in BaP metabolism but also to increase the abundance of other BaP degraders and PAH-RHD genes, resulting in enhanced rhizospheric BaP degradation. Metagenomic and correlation analyses indicated a significant positive relationship between glyoxylate and dicarboxylate metabolism and BaP degradation, suggesting a role for these pathways in rhizospheric BaP biodegradation. By identifying BaP degraders and characterizing their metabolic characteristics within intricate microbial communities, our study offers valuable insights into the mechanisms of bioaugmented rhizoremediation with indigenous bacteria for high-molecular-weight PAHs in petroleum-contaminated soils.

Discovery of bivalent small molecule degraders of cyclin-dependent kinase 7 (CDK7).

Cyclin-dependent kinase 7, along with cyclin H and MAT1, forms the CDK-activating complex (CAK), which directs cell cycle progression via T-loop phosphorylation of cell cycle CDKs. Pharmacological inhibition of CDK7 leads to selective anti-cancer effects in cellular and in vivo models, motivating several ongoing clinical investigations of this target. Current CDK7 inhibitors are either reversible or covalent inhibitors of its catalytic activity. We hypothesized that small molecule targeted protein degradation (TPD) might result in differentiated pharmacology due to the loss of scaffolding functions. Here, we report the design and characterization of a potent CDK7 degrader that is comprised of an ATP-competitive CDK7 binder linked to a CRL2VHL recruiter. JWZ-5-13 effectively degrades CDK7 in multiple cancer cells and leads to a potent inhibition of cell proliferation. Additionally, compound JWZ-5-13 displayed bioavailability in a pharmacokinetic study conducted in mice. Therefore, JWZ-5-13 is a useful chemical probe to investigate the pharmacological consequences of CDK7 degradation.

BTK inhibitors: past, present, and future.

Bruton's tyrosine kinase (BTK) inhibitors have revolutionized the treatment landscape for B cell lymphomas such as chronic lymphocytic leukemia (CLL). The first-in-class BTK inhibitor ibrutinib has recently been succeeded by covalent BTK inhibitors that are safer but still face challenges of resistance mutations. The noncovalent BTK inhibitor pirtobrutinib was recently approved for relapsed and refractory CLL, and whether noncovalent BTK inhibitors will supplant covalent BTK inhibitors as upfront treatment options either alone or in combination will be determined. Meanwhile, newer BTK inhibitors and BTK degraders are vying for their place in the potential future landscape of B cell cancers as well as autoimmune diseases. This review will cover the latest progress in BTK inhibitor development and where the field is moving in light of these recent discoveries.