Discovery of novel hypoxia-activated, nitroimidazole constructed multi-target kinase inhibitors on the basis of AZD9291 for the treatment of human lung cancer.

A group of 4-(1-methyl-1H-indol-3-yl)pyrimidin-2-amine derivatives containing a hypoxia-activated nitroimidazole group were designed as EGFR inhibitors. Among this series, A14 was identified as the optimal compound, exhibiting potent anti-proliferative activities against H1975 and HCC827 cells. Under hypoxic condition, the anti-proliferative activities of A14 improved by 4-6-fold (IC50 < 10 nM), indicating its hypoxia-selectivity. A14's high potency may be attributed to its inhibition against multiple kinases, including EGFR, JAK2, ROS1, FLT3, FLT4 and PDGFRα, which was confirmed by binding assays on a panel of 30 kinases. Furthermore, A14 exhibited good bio-reductive property and could bind with nucleophilic amino acids after being activated under hypoxic conditions. With its anti-proliferative activities and selectivity for hypoxia and oncogenic kinases, A14 shows promise as a multi-target kinase inhibitor for cancer therapy.

Design, synthesis and biological evaluation of the tumor hypoxia-activated PROTACs bearing caged CRBN E3 ligase ligands.

Tumor hypoxia-activated proteolysis targeting chimeras (ha-PROTACs) 9 and 10 were designed and synthesized by incorporating the hypoxia-activated leaving group (1-methyl-2-nitro-1H-imidazol-5-yl)methyl or 4­nitrobenzyl into the structure of the cereblon (CRBN) E3 ligand of an epidermal growth factor receptor 19 deletions (EGFRDel19-based PROTAC 8. The in vitro protein degradation assay demonstrated that 9 and 10 could effectively and selectively degrade EGFRDel19 in tumor hypoxia. Meanwhile, these two compounds showed higher potency in inhibiting cell viability and migration, as well as in promoting cells apoptosis in tumor hypoxia. Moreover, nitroreductase reductive activation assay indicated that prodrugs 9 and 10 could successfully release the active compound 8. This study confirmed the feasibility to develop ha-PROTACs to enhance the selectivity of PROTACs by caging CRBN E3 ligase ligand.

Chemoproteomics reveals arctigenin as a phagophore-closure blocker via targeting ESCRT-I subunit VPS28.

Arctigenin is the active ingredient of the traditional medicines Arctium lappa and Fructus Arctii and has been extensively investigated for its diverse pharmacological functions, including its novel anti-austerity activity. Although several mechanisms have been proposed, the direct target of arctigenin to induce anti-austerity activity remains unclear. In this study, we designed and synthesized photo-crosslinkable arctigenin probes and utilized them in the chemoproteomic profiling of potential target proteins directly in living cells. Vacuolar protein sorting-associated protein 28 (VPS28), a key subunit of the ESCRT-I complex implicated in phagophore closure, was successfully identified. Unexpectedly, we found that arctigenin degraded VPS28 via the ubiquitin-proteasome pathway. We also demonstrated that arctigenin induces a prominent phagophore closure-blockade phenotype in PANC-1 cells. To the best of our knowledge, this is the first report of a small molecule acting as a phagophore-closure blocker and a VPS28 degrader. The arctigenin-modulating phagophore closure provides a new druggable target for cancers that rely heavily on autophagy activation and may also be used for other diseases associated with the ESCRT system.

Research progress and challenges of TRPV1 channel modulators as a prospective therapy for diabetic neuropathic pain.

Diabetic neuropathic pain (DNP) is a common, complex, and severe complication of diabetes. It can lead to increased mortality, lower-limb amputations, and distressing neuropathic symptoms. Available therapies for DNP are broad-spectrum analgesics, related to various side effects. Transient receptor potential vanilloid-1 (TRPV1) is widely expressed within the peripheral and central nervous systems and plays an essential role in pain perception and regulation. Both TRPV1 agonists and antagonists could reduce the sensitivity to nociception. Some exhibit blood glucose homeostasis regulates function by influencing insulin secretion and receptor sensitivity. Since TRPV1 has exhibited the unique advantages of simultaneously managing blood sugar and pain, developing new TRPV1 channel modulators for diabetes-related pain syndrome is a promising alternative to conventional therapy. In this review, the role of TRPV1 in the pathogenesis of DNP has been described and challenges of TRPV1 modulators have been explored to be a new therapy for DNP.

Design, synthesis and biological evaluation of novel tumor hypoxia-activated EGFR tyrosine kinase inhibitors.

Hypoxia is widespread in solid tumors, such as NSCLC, and has become a very attractive target. On the basis of AZD9291 scaffold, novel hypoxia-targeted EGFR inhibitors without the acrylamide warhead but containing hypoxic reductive activation groups were described. Among them, compound JT21 exhibited impressive inhibitory activity (IC50 = 23 nM) against EGFRL858R/T790M and displayed about 21-fold inhibitory activity decrease against EGFRwt. Under hypoxia, JT21 exhibited more significant proliferation inhibitory activities against H1975 cells (IC50 = 7.39 ± 2.20 nM) and HCC827 cells (IC50 = 5.88 ± 0.85 nM) than that of AZD9291, which was about 5 times more effective than normoxia activities. Meanwhile, the weak inhibition effects on A549 and BEAS-2B cells suggested JT21 might be a selective inhibitor for EGFR mutations with low toxicity. Furthermore, JT21 could induce apoptosis of H1975 cells under hypoxia and showed good bio-reductive property.

Design, Synthesis, and Biological Evaluation of 2-Anilino-4-Triazolpyrimidine Derivatives as CDK4/HDACs Inhibitors.

Purpose: To enhance the cytotoxicities of our obtained CDK4 inhibitors and get CDK4/HDACs inhibitors with potent enzymatic inhibitory and anti-proliferative activities. Methods: A series of novel CDK4/HDACs inhibitors were designed and synthesized by incorporating the HDAC pharmacophores (hydroxylamine or o-diaminoaniline) into the basic structure of our newly obtained 2-anilino-4-triazolpyrimidine based CDK4 inhibitors. The enzymatic inhibitory (HDAC1, CDK2, CDK4, and CDK6) activities and cytotoxicities of these compounds were evaluated. Moreover, HDAC isoforms inhibitory activity, cell cycle arrest assay, cell apoptosis analysis, cell migration, and cell colony formation assay were performed for the representative compound 11k. Results: Most of these compounds showed excellent HDAC1 inhibitory activities (IC50s: 0.68~244.5 nM) and anti-proliferative activities against cancer cell lines. Some compounds displayed potent CDK4 inhibitory activities and a certain selectivity towards CDK2 and CDK6. Compound 11k exhibited potent enzymatic (CDK4: IC50=23.59 nM; HDAC1: IC50=61.11 nM; HDAC2: IC50=80.62 nM; HDAC6: IC50=45.33 nM) and anti-proliferative activities against H460, MDA-MB-468, HCT116, and HepG2 cell lines with IC50 values 1.20, 1.34, 2.07, and 2.66 µM, respectively. Further mechanistic studies revealed that compound 11k could arrest the cell cycle in G0/G1 phase and induce apoptosis in HCT116 and MDA-MB-468 cells. In addition, compound 11k significantly inhibited the migration and cell colony formation of H460 and HCT116 cells. Conclusion: This study suggested that the incorporation of the HDAC pharmacophore into CDK4 inhibitor scaffold to design CDK/HDAC inhibitors might be a tractable strategy to enhance the antitumor potency of compounds.