Branched-chain amino acid transaminase 1 confers EGFR-TKI resistance through epigenetic glycolytic activation.

Third-generation EGFR tyrosine kinase inhibitors (TKIs), exemplified by osimertinib, have demonstrated promising clinical efficacy in the treatment of non-small cell lung cancer (NSCLC). Our previous work has identified ASK120067 as a novel third-generation EGFR TKI with remarkable antitumor effects that has undergone New Drug Application (NDA) submission in China. Despite substantial progress, acquired resistance to EGFR-TKIs remains a significant challenge, impeding the long-term effectiveness of therapeutic approaches. In this study, we conducted a comprehensive investigation utilizing high-throughput proteomics analysis on established TKI-resistant tumor models, and found a notable upregulation of branched-chain amino acid transaminase 1 (BCAT1) expression in both osimertinib- and ASK120067-resistant tumors compared with the parental TKI-sensitive NSCLC tumors. Genetic depletion or pharmacological inhibition of BCAT1 impaired the growth of resistant cells and partially re-sensitized tumor cells to EGFR TKIs. Mechanistically, upregulated BCAT1 in resistant cells reprogrammed branched-chain amino acid (BCAA) metabolism and promoted alpha ketoglutarate (α-KG)-dependent demethylation of lysine 27 on histone H3 (H3K27) and subsequent transcriptional derepression of glycolysis-related genes, thereby enhancing glycolysis and promoting tumor progression. Moreover, we identified WQQ-345 as a novel BCAT1 inhibitor exhibiting antitumor activity both in vitro and in vivo against TKI-resistant lung cancer with high BCAT1 expression. In summary, our study highlighted the crucial role of BCAT1 in mediating resistance to third-generation EGFR-TKIs through epigenetic activation of glycolysis in NSCLC, thereby supporting BCAT1 as a promising therapeutic target for the treatment of TKI-resistant NSCLC.

Discovery of a novel BTK inhibitor S-016 and identification of a new strategy for the treatment of lymphomas including BTK inhibitor-resistant lymphomas.

Bruton's tyrosine kinase (BTK) has emerged as a therapeutic target for B-cell malignancies, which is substantiated by the efficacy of various irreversible or reversible BTK inhibitors. However, on-target BTK mutations facilitating evasion from BTK inhibition lead to resistance that limits the therapeutic efficacy of BTK inhibitors. In this study we employed structure-based drug design strategies based on established BTK inhibitors and yielded a series of BTK targeting compounds. Among them, compound S-016 bearing a unique tricyclic structure exhibited potent BTK kinase inhibitory activity with an IC50 value of 0.5 nM, comparable to a commercially available BTK inhibitor ibrutinib (IC50 = 0.4 nM). S-016, as a novel irreversible BTK inhibitor, displayed superior kinase selectivity compared to ibrutinib and significant therapeutic effects against B-cell lymphoma both in vitro and in vivo. Furthermore, we generated BTK inhibitor-resistant lymphoma cells harboring BTK C481F or A428D to explore strategies for overcoming resistance. Co-culture of these DLBCL cells with M0 macrophages led to the polarization of M0 macrophages toward the M2 phenotype, a process known to support tumor progression. Intriguingly, we demonstrated that SYHA1813, a compound targeting both VEGFR and CSF1R, effectively reshaped the tumor microenvironment (TME) and significantly overcame the acquired resistance to BTK inhibitors in both BTK-mutated and wild-type BTK DLBCL models by inhibiting angiogenesis and modulating macrophage polarization. Overall, this study not only promotes the development of new BTK inhibitors but also offers innovative treatment strategies for B-cell lymphomas, including those with BTK mutations.

Dual-network DNA-silk fibroin hydrogels with controllable surface rigidity for regulating chondrogenic differentiation.

Osteoarthritis (OA) is a common joint disease known for cartilage degeneration, leading to a substantial burden on individuals and society due to its high disability rate. However, current clinical treatments for cartilage defects remain unsatisfactory due to the unclear mechanisms underlying cartilage regeneration. Tissue engineering hydrogels have emerged as an attractive approach in cartilage repair. Recent research studies have indicated that stem cells can sense the mechanical strength of hydrogels, thereby regulating their differentiation fate. In this study, we present the groundbreaking construction of dual-network DNA-silk fibroin (SF) hydrogels with controllable surface rigidity. The supramolecular networks, formed through DNA base-pairing, induce the development of ß-sheet structures by constraining and aggregating SF molecules. Subsequently, SF was cross-linked via horseradish peroxidase (HRP)-mediated enzyme reactions to form the second network. Experimental results demonstrated a positive correlation between the surface rigidity of dual-network DNA-SF hydrogels and the DNA content. Interestingly, it was observed that dual-network DNA-SF hydrogels with moderate surface rigidity exhibited the highest effectiveness in facilitating the migration of bone marrow mesenchymal stem cells (BMSCs) and their chondrogenic differentiation. Transcriptome sequencing further confirmed that dual-network DNA-SF hydrogels primarily enhanced chondrogenic differentiation of BMSCs by upregulating the Wnt and TGF-ß signaling pathways while accelerating collagen II synthesis. Furthermore, in vivo studies revealed that dual-network DNA-SF hydrogels with moderate surface rigidity significantly accelerated cartilage regeneration. In summary, the dual-network DNA-SF hydrogels represent a promising and novel therapeutic strategy for cartilage regeneration.

Extracellular derivatives for bone metabolism.

BACKGROUND: Bone metabolism can maintain the normal homeostasis and function of bone tissue. Once the bone metabolism balance is broken, it will cause osteoporosis, osteoarthritis, bone defects, bone tumors, or other bone diseases. However, such orthopedic diseases still have many limitations in clinical treatment, such as drug restrictions, drug tolerance, drug side effects, and implant rejection. AIM OF REVIEW: In complex bone therapy and bone regeneration, extracellular derivatives have become a promising research focus to solve the problems of bone metabolic diseases. These derivatives, which include components such as extracellular matrix, growth factors, and extracellular vesicles, have significant therapeutic potential. It has the advantages of good biocompatibility, low immune response, and dynamic demand for bone tissue. The purpose of this review is to provide a comprehensive perspective on extracellular derivatives for bone metabolism and elucidate the intrinsic properties and versatility of extracellular derivatives. Further discussion of them as innovative advanced orthopedic materials for improving the effectiveness of bone therapy and regeneration processes. KEY SCIENTIFIC CONCEPTS OF REVIEW: In this review, we first listed the types and functions of three extracellular derivatives. Then, we discussed the effects of extracellular derivatives of different cell sources on bone metabolism. Subsequently, we collected applications of extracellular derivatives in the treatment of bone metabolic diseases and summarized the advantages and challenges of extracellular derivatives in clinical applications. Finally, we prospected the extracellular derivatives in novel orthopedic materials and clinical applications. We hope that the comprehensive understanding of extracellular derivatives in bone metabolism will provide new solutions to bone diseases.

Preclinical and early clinical studies of a novel compound SYHA1813 that efficiently crosses the blood-brain barrier and exhibits potent activity against glioblastoma.

Glioblastoma (GBM) is the most common and aggressive malignant brain tumor in adults and is poorly controlled. Previous studies have shown that both macrophages and angiogenesis play significant roles in GBM progression, and co-targeting of CSF1R and VEGFR is likely to be an effective strategy for GBM treatment. Therefore, this study developed a novel and selective inhibitor of CSF1R and VEGFR, SYHA1813, possessing potent antitumor activity against GBM. SYHA1813 inhibited VEGFR and CSF1R kinase activities with high potency and selectivity and thus blocked the cell viability of HUVECs and macrophages and exhibited anti-angiogenetic effects both in vitro and in vivo. SYHA1813 also displayed potent in vivo antitumor activity against GBM in immune-competent and immune-deficient mouse models, including temozolomide (TMZ) insensitive tumors. Notably, SYHA1813 could penetrate the blood-brain barrier (BBB) and prolong the survival time of mice bearing intracranial GBM xenografts. Moreover, SYHA1813 treatment resulted in a synergistic antitumor efficacy in combination with the PD-1 antibody. As a clinical proof of concept, SYHA1813 achieved confirmed responses in patients with recurrent GBM in an ongoing first-in-human phase I trial. The data of this study support the rationale for an ongoing phase I clinical study (ChiCTR2100045380).

Design, Synthesis, and Evaluation of (R)-8-((Tetrahydrofuran-2-yl)methyl)pyrido[2,3-d]pyrimidin-7-ones as Novel Selective ACK1 Inhibitors to Combat Acquired Resistance to the Third-Generation EGFR Inhibitor.

Activated Cdc42-associated kinase 1 (ACK1) alterations have been considered to mediate bypass acquired resistance to the third-generation EGFR inhibitors (ASK120067 and osimertinib) in NSCLC. Despite many efforts to develop ACK1 small molecule inhibitors, no selective inhibitors have entered clinical trials. We used structure-based drug design to obtain a series of (R)-8-((tetrahydrofuran-2-yl)methyl)pyrido [2,3-d]pyrimidin-7-ones as novel selective ACK1 inhibitors. One of the representative compounds, 10zi, potently inhibited ACK1 kinase with an IC50 of 2.1 nM, while sparing SRC kinase (IC50 = 218.7 nM). Further, 10zi displayed good kinome selectivity in a profiling of 468 kinases. In the ASK120067-resistant lung cancer cell line (67R), 10zi dose-dependently inhibited the phosphorylation of ACK1 and downstream AKT pathway and showed a strong synergistic anti-tumor effect in combination with ASK120067 in vitro. Additionally, 10zi also exhibited reasonable PK profiles with an oral bioavailability of 19.8% at the dose of 10 mg/kg, which provided a promising lead for further development of new anticancer drugs.

Discovery of HCD3514 as a potent EGFR inhibitor against C797S mutation in vitro and in vivo.

Osimertinib (AZD9291), a third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKI), has significantly improved the survival of non-small cell lung cancer (NSCLC) patients with EGFRT790M mutation, the major mechanism of acquired resistance to first-generation EGFR TKI. However, resistance to AZD9291 arises eventually and EGFRC797S mutation was reported to be a major resistance mechanism. Thus, it is highly valuable to develop novel EGFR fourth-generation inhibitors targeting C797S mutation to override the acquired resistance. In this study, we identified HCD3514 as a novel EGFR fourth-generation inhibitors targeting C797S triple mutation. It strongly inhibited EGFRL858R/T790M/C797S and EGFR19del/T790M/C797S mutations with IC50 values of 1.0 and 2.0 nM, respectively. HCD3514 dose-dependently inhibited the activation of EGFR in both engineered BaF3 cells and tumor cells harboring EGFRC797S triple mutant and thus effectively suppressed the proliferation of the cells. Moreover, HCD3514 caused a dose-dependent increase of apoptosis in C797S triple mutant cells accompanied by increased levels of cleaved caspase-3 and cleaved PARP. Furthermore, HCD3514 induced tumor growth inhibition in EGFR19del/T790M/C797S xenograft model as a single oral agent by decreasing the activation of EGFR. In addition to EGFRC797S triple mutations, HCD3514 also potently and selectively inhibited EGFRT790M double mutations (L858R/T790M and 19del/T790M). Collectively, HCD3514 is a highly selective and potent EGFR inhibitor against EGFRC797S triple mutations as well as EGFRT790M double mutations and is confirmed potently anti-tumor activity in preclinical models.

ASK120067 potently suppresses B-cell or T-cell malignancies in vitro and in vivo by inhibiting BTK and ITK.

Hyperactivation of Bruton's tyrosine kinase (BTK) or interleukin-2-inducible T cell kinase (ITK) has been attributed to the pathogenesis of B-cell lymphoma or T-cell leukemia, respectively, which suggests that Bruton's tyrosine kinase and interleukin-2-inducible T cell kinase are critical targets for the treatment of hematological malignancies. We identified a novel third-generation epidermal growth factor receptor (EGFR) inhibitor, ASK120067 (limertinib) in our previous research, which has been applied as a new drug application against non-small cell lung cancer in China. In this work, we found that ASK120067 displayed potent in vitro inhibitory efficacy against Bruton's tyrosine kinase protein and interleukin-2-inducible T cell kinase protein via covalent binding. In cell-based assays, ASK120067 dose-dependently suppressed Bruton's tyrosine kinase phosphorylation and exhibited anti-proliferation potency by inducing apoptosis in numerous B-lymphoma cells. Meanwhile, it caused growth arrest and induced the apoptosis of T-cell leukemia cells by attenuating interleukin-2-inducible T cell kinase activation. Oral administration of ASK120067 led to significant tumor regression in B-cell lymphoma and T-cell leukemia xenograft models by weakening Bruton's tyrosine kinase and interleukin-2-inducible T cell kinase signaling, respectively. Taken together, our studies demonstrated that ASK120067 exerted preclinical anti-tumor activities against B-/T-cell malignancy by targeting BTK/ITK.

LS-106, a novel EGFR inhibitor targeting C797S, exhibits antitumor activities both in vitro and in vivo.

With the wide clinical use of the third-generation epidermal growth factor receptor (EGFR) inhibitor osimertinib for the treatment of EGFR-mutated non-small cell lung cancer (NSCLC), acquired resistance caused by EGFR C797S tertiary mutation has become a concern. Therefore, fourth-generation EGFR inhibitors that could overcome this mutation have gained increasing attention in recent years. Here, we identified LS-106 as a novel EGFR inhibitor against C797S mutation and evaluated its antitumor activity both in vitro and in vivo. In cell-free assay, LS-106 potently inhibited the kinase activities of EGFR19del/T790M/C797S and EGFRL858R/T790M/C797S with IC50 values of 2.4 nmol/L and 3.1 nmol/L, respectively, which was more potent than osimertinib. Meanwhile, LS-106 exhibited comparable kinase inhibitory effect to osimertinib on EGFRL858R/T790M and wild-type EGFR. Results from cellular experiments demonstrated that LS-106 potently blocked the phosphorylation of EGFR C797S triple mutations in the constructed BaF3 cells that highly expressed EGFR19del/T790M/C797S or EGFRL858R/T790M/C797S , and thus inhibited the proliferation of these cells. We also constructed tumor cells harboring EGFR19del/T790M/C797S (named PC-9-OR cells) using the CRISPR/Cas9 system and found that LS-106 markedly suppressed the activation of EGFR19del/T790M/C797S and the proliferation of PC-9-OR cells. Moreover, cells harboring EGFR19del/T790M/C797S underwent remarkable apoptosis upon LS-106 treatment. In vivo experiments further demonstrated that oral administration of LS-106 caused significant tumor regression in a PC-9-OR xenograft model, with a tumor growth inhibition rate (TGI) of 83.5% and 136.6% at doses of 30 and 60 mg/kg, respectively. Taken together, we identified LS-106 as a novel fourth-generation EGFR inhibitor against C797S mutation and confirmed its preclinical antitumor effects in C797S-triple-mutant tumor models.

Discovery of a novel third-generation EGFR inhibitor and identification of a potential combination strategy to overcome resistance.

BACKGROUND: Non-small cell lung cancer (NSCLC) patients with activating EGFR mutations initially respond to first-generation EGFR inhibitors; however, the efficacy of these drugs is limited by acquired resistance driven by the EGFR T790M mutation. The discovery of third-generation EGFR inhibitors overcoming EGFR T790M and their new resistance mechanisms have attracted much attention. METHODS: We examined the antitumor activities and potential resistance mechanism of a novel EGFR third-generation inhibitor in vitro and in vivo using ELISA, SRB assay, immunoblotting, flow cytometric analysis, kinase array, qRT-PCR and tumor xenograft models. The clinical effect on a patient was evaluated by computed tomography scan. RESULTS: We identified compound ASK120067 as a novel inhibitor of EGFR T790M, with selectivity over EGFR WT. ASK120067 exhibited potent anti-proliferation activity in tumor cells harboring EGFR T790M (NCI-H1975) and sensitizing mutations (PC-9 and HCC827) while showed moderate or weak inhibition in cells expressing EGFR WT. Oral administration of ASK120067 induced tumor regression in NSCLC xenograft models and in a PDX model harboring EGFR T790M. The treatment of one patient with advanced EGFR T790M-positive NSCLC was described as proof of principle. Moreover, we found that hyperphosphorylation of Ack1 and the subsequent activation of antiapoptotic signaling via the AKT pathway contributed to ASK120067 resistance. Concomitant targeting of EGFR and Ack1 effectively overrode the acquired resistance of ASK120067 both in vitro and in vivo. CONCLUSIONS: Our results idenfity ASK120067 as a promising third-generation EGFR inhibitor and reveal for the first time that Ack1 activation as a novel resistance mechanism to EGFR inhibitors that guide to potential combination strategy.

Design and synthesis of Imidazo[1,2-b]pyridazine IRAK4 inhibitors for the treatment of mutant MYD88 L265P diffuse large B-cell lymphoma.

Harboring MYD88 L265P mutation triggers tumors growth through the activation of NF-κB by interleukin-1 receptor associated kinase 4 (IRAK4) in diffuse large B-cell lymphoma (DLBCL), highlighting IRAK4 as a therapeutic target for tumors driven by aberrant MYD88 signaling. Herein, we report the design, synthesis, and structure-activity relationships of imidazo[1,2-b]pyridazines as potent IRAK4 inhibitors. The representative compound 5 exhibited excellent IRAK4 potency (IRAK4 IC50 = 1.3 nM) and favorable kinase selectivity profile. It demonstrated cellular selectivity for activated B cell-like (ABC) subtype DLBCL with MYD88 L265P mutation in cytotoxicity assay. The kinase inhibitory efficiency of compound 5 was further validated by Western blot analysis of phosphorylation of IRAK4 and downstream signaling in OCI-LY10 and TMD8 cells. Besides, combination of compound 5 and BTK inhibitor ibrutinib synergistically reduced the viability of TMD8 cells. These results indicated that compound 5 could be a promising IRAK4 inhibitor for the treatment of mutant MYD88 DLBCL.

Discovery and biological evaluation of N-(3-(7-((2-methoxy-4-(4-methylpiperazin-1-yl)phenyl)amino)-4-methyl-2-oxo-2H-pyrimido[4,5-d][1,3]oxazin-1(4H)-yl)phenyl)acrylamide as potent Bruton's tyrosine kinase inhibitors.

Bruton's tyrosine kinase (BTK) is a key component of the B cell receptor (BCR) signaling pathway and plays a crucial role in B cell malignancies and autoimmune disorders; thus, it is an attractive target for the treatment of B cell related diseases. Here, we evaluated the BTK inhibitory activity of a series of pyrimido[4,5-d][1,3]oxazin-2-one derivatives. Combining this evaluation with structure-activity relationship (SAR) analysis, we found that compound 2 exhibited potent BTK kinase inhibitory activity, with an IC50 of 7 nM. This derivative markedly inhibited BTK activation in TMD8 B cell lymphoma cells and thus inhibited the in vitro growth of the cells. Further studies revealed that compound 2 dose dependently arrested TMD8 cells at G1 phase, accompanied by decreased levels of Rb, phosphorylated Rb, and cyclin D1. Moreover, following treatment with compound 2, TMD8 cells underwent apoptosis associated with PARP and caspase 3 cleavage. Interestingly, the results of the kinase activity assay on a small panel of 35 kinases showed that the kinase selectivity of compound 2 was superior to that of the first-generation inhibitor ibrutinib, suggesting that compound 2 could be a second-generation inhibitor of BTK. In conclusion, we identified a potent and highly selective BTK inhibitor worthy of further development.

Discovery and Biological evaluation of pyrimido[4,5-d]pyrimidine-2,4(1H,3H)-dione derivatives as potent Bruton's tyrosine kinase inhibitors.

Aberrant activation of B cell receptor (BCR) signal transduction cascade contributes to the propagation and maintenance of B cell malignancies. The discovery of mall molecules with high potency and selectivity against Bruton's tyrosine kinase (BTK), a key signaling molecule in this cascade, is particularly urgent in modern treatment regimens. Herein, a series of pyrimido[4,5-d]pyrimidine-2,4(1H,3H)-dione derivatives were reported as potent BTK inhibitors. Compounds 17 and 18 displayed strong BTK inhibitory activities in the enzymatic inhibition assay, with the IC50 values of 1.2 and 0.8 nM, respectively, which were comparable to that of ibrutinib (IC50 = 0.6 nM). Additionally, compound 17 had a more selective profile over EGFR than ibrutinib. According to the putative binding poses, the molecular basis of this series of compounds with respect to potency against BTK and selectivity over EGFR was elucidated. In further experiments at cellular level, compounds 17 and 18 significantly inhibited the proliferation of Ramos and TMD8 cells. And they arrested 75.4% and 75.2% of TMD8 cells in G1 phase, respectively, at the concentration of 1 µM.

Discovery and biological evaluation of N5-substituted 6,7-dioxo-6,7-dihydropteridine derivatives as potent Bruton's tyrosine kinase inhibitors.

Bruton's tyrosine kinase (BTK) plays a critical role in B cell receptor (BCR)-mediated signaling pathways responsible for the development and function of B cells, which makes it an attractive target for the treatment of many types of B-cell malignancies. Herein, a series of N5-substituted 6,7-dioxo-6,7-dihydropteridine-based, irreversible BTK inhibitors were reported with IC50 values ranging from 1.9 to 236.6 nM in the enzymatic inhibition assay. Compounds 6 and 7 significantly inhibited the proliferation of Ramos cells which overexpress the BTK enzyme, as well as the autophosphorylation of BTK at Tyr223 and the activation of its downstream signaling molecule PLCγ2. Overall, this series of compounds could provide a promising starting point for further development of potent BTK inhibitors for B-cell malignancy treatment.

Discovery of 4,7-Diamino-5-(4-phenoxyphenyl)-6-methylene-pyrimido[5,4- b]pyrrolizines as Novel Bruton's Tyrosine Kinase Inhibitors.

An alternative medicinal chemistry approach was conducted on Bruton's tyrosine kinase (BTK) inhibitor 1 (ibrutinib) by merging the pyrazolo[3,4- d]pyrimidine component into a tricyclic skeleton. Two types of compounds were prepared, and their biochemical activities on BTK as well as stereochemistry effects were determined. Structural optimization focusing on the reactive binding group to BTK Cys481 and on the metabolic site guided by metabolic study were conducted. 7S was identified as the most potent showing an IC50 value of 0.4 nM against BTK and 16 nM against BTK-dependent TMD8 cells. Compared to 1, 7S was slightly more selective with strong inhibition on the B-cell receptor signaling pathway. In a TMD8 cell-derived animal xenograft model, 7S showed a relative tumor volume of 5.3 at 15 mg/kg QD dosage that was more efficacious than 1 (RTV 6.6) at a higher dose of 25 mg/kg QD. All these results suggest 7S as a new BTK inhibitor worthy of further profiling.