Novel spirooxindole alkaloid derivatives from the medicinal insect Blaps japanensis and their biological evaluation.

Blapspirooxindoles A-C (1-3), three novel spirooxindole alkaloids with a unique spiro[chromane-4,3'-indoline]-2,2'-dione motif, blapcumaranons A and B (4 and 5), two new 2-cumaranon derivatives, blapoxindoles A-J (6-15), ten new oxindole alkaloid derivatives, along with one known compound (16), were isolated from the whole bodies of Blaps japanensis. Their structures including absolute configurations were determined by using spectroscopic, X-ray crystallographic, and computational methods. Compounds 1-11 and 13 exist as racemic mixtures in nature, and their (-)- and (+)-antipodes were separated by chiral HPLC. Biological evaluations of these compounds were determined with multiple assays including anti-tumor, anti-inflammatory, and renal protection activities in vitro. Several compounds displayed effective activity in one or more assays.

Eugenilones A-N: sesquiterpenoids from the fruits of Eugenia uniflora.

(+) and (-)-Eugenilones A-K, 11 pairs of undescribed enantiomeric sesquiterpenoids, together with three undescribed biogenetically related members eugenilones L-N, were discovered from the fruits of Eugenia uniflora Linn. (Myrtaceae). Structurally, eugenilones A-D were four caged sesquiterpenoids featuring 9,10-dioxatricyclo [6.2.2.02,7]dodecane, 11-oxatricyclo [5.3.1.03,8]undecane, and tricyclo [4.4.0.02,8]decane cores, respectively. Eugenilones E-K were eudesmane-type sesquiterpenoids, while eugenilones L-N were epoxy germacrane-type sesquiterpenoids. Notably, eugenilones A-K were efficiently resolved by chiral HPLC to give 11 pairs of optically pure enantiomers. The structures and absolute configurations of eugenilones A-N were determined through spectroscopic analyses, X-ray crystallography, and ECD calculations. The putative biosynthetic pathways for these undescribed isolates were proposed. Moreover, eugenilones A and E exhibited significant anti-inflammatory effects by inhibiting LPS-stimulated NO overproduction in RAW264.7 cells (IC50 values of 4.89 ± 0.37 µM and 20.89 ± 1.49 µM, respectively) and TNF-α-induced NF-κB activation in HEK293 cells (IC50 values of 10.97 ± 1.03 µM and 28.63 ± 1.59 µM, respectively).

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.

Design, Synthesis, and Biological Evaluation of 2-Formyl Tetrahydronaphthyridine Urea Derivatives as New Selective Covalently Reversible FGFR4 Inhibitors.

Aberrant FGF19/FGFR4 signaling is an oncogenic driver force for the development of human hepatocellular carcinoma (HCC). A series of 2-formyl tetrahydronaphthyridine urea derivatives were designed and synthesized as new covalently reversible inhibitors of FGFR4. The representative compound 9ka exhibited an IC50 value of 5.4 nM against FGFR4 and demonstrated extraordinary kinome selectivity. Compound 9ka also exhibited good oral pharmacokinetic properties with an AUC(0-t) value of 38 950.06 h·ng/mL, a T1/2 value of 3.06 h, and an oral bioavailability of 50.97%, at an oral dose of 25 mg/kg in Sprague-Dawley (SD) rats. Furthermore, compound 9ka induced significant tumor regressions in a xenograft mouse model of Hep3B2.1-7 HCC cell line without an obvious sign of toxicity upon 30 mg/kg oral administration. Compound 9ka may serve as a promising lead compound for further anticancer drug development.

Investigation of Covalent Warheads in the Design of 2-Aminopyrimidine-based FGFR4 Inhibitors.

Covalent kinase inhibitors are rapidly emerging as a class of therapeutics with clinical benefits. Herein we report a series of selective 2-aminopyrimidine-based fibroblast growth factor receptor 4 (FGFR4) inhibitors exploring different types of cysteine-targeting warheads. The structure-activity relationship study revealed that the chemically tuned warheads α-fluoro acrylamide, vinylsulfonamide, and acetaldehyde amine were suitable as covalent warheads for the design of selective FGFR4 inhibitors. Compounds 6a, 6h, and 6i selectively suppressed FGFR4 enzymatic activity with IC50 values of 53 ± 18, 45 ± 11, and 16 ± 4 nM, respectively, while sparing FGFR1/2/3. X-ray crystal structure and MALDI-TOF studies demonstrated that compound 6h bearing the α-fluoro acrylamide binds to FGFR4 with an irreversible binding mode, whereas compound 6i with an acetaldehyde amine binds to FGFR4 with a reversible covalent mode. 6h and 6i might provide some fundamental structural information for the rational design of new selective FGFR4 inhibitors.

Neolignans and Norlignans from Insect Medicine Polyphaga plancyi and Their Biological Activities.

Ten neolignans or norlignans (1-10) including eight new compounds were isolated from the whole bodies of Polyphaga plancyi Bolivar. Their structures were identified by spectroscopic data. Compounds 3, 4, 8, and 9 are racemates indicated by chiral HPLC analysis. Chiral separation followed by ECD calculations allowed to clarify the absolute configurations of all the antipodes. All the new compounds were evaluated for their biological properties toward extracellular matrix in rat renal proximal tubular cells, human cancer cells (K562, A549, and Huh7), EV71, ROCK2, JAK3, DDR1, and coagulation.

Sulfur and nitrogen-containing compounds from the whole bodies of Blaps japanensis.

Pipajiains H-J (1-3), three new phenolic derivatives with an unusual sulfone group, pipajiamides A-C (4-6), three new amide derivatives, pipajiaine A (7), one new imidazole analogue, and pipajiaine B (8), a pair of new pyrrolidine derivatives, along with three known compounds were isolated from the insect Blaps japanensis. Their structures were identified by spectroscopic and computational methods. Chiral HPLC was used to separate the (-)- and (+)-antipodes of 4 and 8. Biological activities of all the new compounds against extracellular matrix in rat renal proximal tubular cells, human cancer cells (A549, Huh-7, and K562), COX-2, ROCK1, and JAK3 were evaluated. The results show that compounds 2, (+)-4, and (-)-4 are active against kidney fibrosis, whereas, compound 9 is active toward human cancer cells, inflammation, and JAK3 kinase.

Design, synthesis, and Structure-Activity Relationships (SAR) of 3-vinylindazole derivatives as new selective tropomyosin receptor kinases (Trk) inhibitors.

Neurotrophic receptor tyrosine kinase (NTRK) fusions are oncogenic drivers for a variety of adult and pediatric tumors, validated by the US FDA approval of small molecular Trk inhibitors Larotrectinib (1, LOXO-101) and Entrectinib (2). However, gene mutation mediated resistance becomes a major challenge for Trk inhibitor therapies. Herein, we report the design, synthesis and Structure-Activity Relationship investigation of a series of 3-vinylindazole derivatives as new Trk inhibitors with low nanomolar potencies. A representative compound, 7mb, binds to TrkA/B/C with Kd values of 1.6, 3.1 and 4.9 nM, and suppresses their kinase functions with IC50 values of 1.6, 2.9 and 2.0 nM, respectively, but is obviously less potent for the majority of a panel of 403 wild-type kinases in a KINOMEscan selectivity investigation. The compound also potently suppresses proliferation of a panel of BaF3 cells stably transformed with NTRK fusions with IC50 values in low nM ranges. Additionally, the compound exhibits strong inhibition against the Larotrectinib-resistant cells with NTRK1-G667C or NTRK3-G696A mutations with IC50 values of 0.031 and 0.018 µM, respectively. Although the relatively poor oral bioavailability of 7mb will limit its further development, this compound may be utilized a lead molecule for further structural optimization.

Ansamycin derivatives from the marine-derived Streptomyces sp. SCSGAA 0027 and their cytotoxic and antiviral activities.

Fourteen ansamycin derivatives including seven new herbimycins G-L (1-6) and divergolide O (7), and seven known analogues were isolated from a culture broth of the marine-derived Streptomyces sp. SCSGAA 0027. Their complete structures were determined by detailed analysis of spectroscopic data and quantum chemical calculations. Compounds 1-5 and 7 featured an additional eight-membered O-heterocycle that has rarely been reported for ansamycins, and the Z,Z- and E,E-configurations for Δ2,Δ4 were reported for the first time in geldanamycin analogues. Compound 1 exhibited weak inhibition activity towards Hsp90α with an IC50 value of 96 µM, 2-5 showed mild cytotoxicity against four human cancer cell lines with IC50 values ranging from 13 µM to 86 µM, and 7 had moderate anti-HSV-1 activity with an IC50 value of 19 µM and very weak cytotoxicity towards Vero cell. The possible biosynthetic pathways for 1-5 were proposed. And their structure-bioactivity relationship was also discussed.

Design and Optimization of 3'-(Imidazo[1,2-a]pyrazin-3-yl)-[1,1'-biphenyl]-3-carboxamides as Selective DDR1 Inhibitors.

DDR1 is considered as a promising target for cancer therapy, and selective inhibitors against DDR1 over other kinases may be considered as promising therapeutic agents. Herein, we have identified a series of 3'-(imidazo[1,2-a]pyrazin-3-yl)-[1,1'-biphenyl]-3-carboxamides as novel selective DDR1 inhibitors. Among these, compound 8v potently inhibited DDR1 with an IC50 of 23.8 nM, while it showed less inhibitory activity against DDR2 (IC50 = 1740 nM) and negligible activities against Bcr-Abl (IC50 > 10 µM) and c-Kit (IC50 > 10 µM). 8v also exhibited excellent selectivity in a KINOMEscan screening platform with 468 kinases. This compound dose-dependently suppressed NSCLC cell tumorigenicity, migration, and invasion. Collectively, these studies support its potential application for treatment of NSCLC.

(±) Gancochlearols A and B: cytotoxic and COX-2 inhibitory meroterpenoids from Ganoderma cochlear.

(+)- and (-)-gancochlearols A (1) and B (2), two pairs of dimeric mertoterpenoid enantiomers were isolated from the fruiting bodies of Ganoderma cochlear. Their structures were identified by spectroscopic methods. Biological assessments show that the enantiomers of 1 and 2 are cytotoxic against three human cancer cell lines (A549, K562, Huh-7) and could inhibit COX-2 expression with IC50 values less than 10 µM.

Design, Synthesis, and Structure-Activity Relationships of 1,2,3-Triazole Benzenesulfonamides as New Selective Leucine-Zipper and Sterile-α Motif Kinase (ZAK) Inhibitors.

ZAK is a new promising target for discovery of drugs with activity against antihypertrophic cardiomyopathy (HCM). A series of 1,2,3-triazole benzenesulfonamides were designed and synthesized as selective ZAK inhibitors. One of these compounds, 6p binds tightly to ZAK protein (Kd = 8.0 nM) and potently suppresses the kinase function of ZAK with single-digit nM (IC50 = 4.0 nM) and exhibits excellent selectivity in a KINOMEscan screening platform against a panel of 403 wild-type kinases. This compound dose dependently blocks p38/GATA-4 and JNK/c-Jun signaling and demonstrates promising in vivo anti-HCM efficacy upon oral administration in a spontaneous hypertensive rat (SHR) model. Compound 6p may serve as a lead compound for new anti-HCM drug discovery.

2-Amino-2,3-dihydro-1H-indene-5-carboxamide-Based Discoidin Domain Receptor 1 (DDR1) Inhibitors: Design, Synthesis, and in Vivo Antipancreatic Cancer Efficacy.

A series of 2-amino-2,3-dihydro-1H-indene-5-carboxamides were designed and synthesized as new selective discoidin domain receptor 1 (DDR1) inhibitors. One of the representative compounds, 7f, bound with DDR1 with a Kd value of 5.9 nM and suppressed the kinase activity with an half-maximal (50%) inhibitory concentration value of 14.9 nM. 7f potently inhibited collagen-induced DDR1 signaling and epithelial-mesenchymal transition, dose-dependently suppressed colony formation of pancreatic cancer cells, and exhibited promising in vivo therapeutic efficacy in orthotopic mouse models of pancreatic cancer.

Quinolone antibiotic derivatives as new selective Axl kinase inhibitors.

Axl is a new promising molecular target for antineoplastic therapies. A series of quinolone antibiotic derivatives were designed and synthesized as new selective Axl inhibitors. One of the most promising compound 8i bound tightly to Axl with a Kd value of 1.1 nM, and inhibited its kinase activity with an IC50 value of 26 nM. The compound also significantly inhibited the phosphorylation of Axl and dose dependently inhibited cell invasion and migration in TGF-ß1 induced MDA-MD-231 breast cancer cells. In addition, 8i demonstrated reasonable pharmacokinetic properties and exhibited extraordinary target selectivity over 468 kinases except for Flt3 (IC50 = 50 nM)), with a S(10) and S(35) value of 0.022 and 0.42 at 1.0 µM, respectively. Compound 8i may serve as a new valuable lead compound for future anticancer drug discovery.

Nucleoside and N-acetyldopamine derivatives from the insect Aspongopus chinensis.

Two new nucleoside derivatives, named asponguanosines A and B (1 and 2), three new N-acetyldopamine analogues, aspongamides C-E (3-5), one new sesquiterpene, aspongnoid D (6), and three known compounds were isolated from the medicinal insect Aspongopus chinensis. Their structures including absolute configurations were assigned by using spectroscopic methods and ECD and 13C NMR calculations. Biological activities of compounds 3-7 towards human cancer cells, COX-2, ROCK1, and JAK3 were evaluated.

(±) Cochlearoids N-P: three pairs of phenolic meroterpenoids from the fungus Ganoderma cochlear and their bioactivities.

Three pairs of meroterpenoids (±) cochlearoids N-P (1-3) were isolated from the fruiting bodies of Ganoderma cochlear. Their structures including absolute configurations were assigned by spectroscopic techniques. All the isolated compounds were tested for their inhibitory activities toward BRD4, human cancer cells, and micro-organisms. The results show that the enantiomers of (±)-1 are BRD4 inhibitors, (-)-1 and (+)-3 are cytotoxic against human cancer cells (K562) with IC50 values of 7.68 and 6.68 µM, respectively. Besides compounds (±)-2 and (±)-3 exhibit potent inhibitory activity against Staphylococcus aureus with IC50 values in the range of 5.43-17.99 µM.

Structure-based drug design: Synthesis and biological evaluation of quinazolin-4-amine derivatives as selective Aurora A kinase inhibitors.

Aurora kinases play critical roles in the regulation of the cell cycle and mitotic spindle assembly. Aurora A kinase, a member of the Aurora protein family, is frequently highly expressed in tumors, and selective Aurora A inhibition serves as a significant component of anticancer therapy. However, designing highly selective Aurora A inhibitors is difficult because Aurora A and B share high homology and differ only by three residues in their ATP-binding pockets. Through structure-based drug design, we designed and synthesized a series of novel quinazolin-4-amine derivatives. These derivatives act as selective Aurora A kinase inhibitors by exploiting the structural differences between Aurora A and B. The selectivities of most compounds were improved (the best up to >757-fold) when comparing with the lead compound (3-fold). In vitro biochemical and cellular assays revealed that compound 6 potently inhibited Aurora A kinase and most human tumor cells. Furthermore, compound 6 effectively suppressed carcinoma, such as triple-negative breast cancers (TNBC) in an animal model. Therefore, compound 6 might serve as a promising anticancer drug. Moreover, through molecular dynamic (MD) analysis, we have identified that a salt bridge formed in Aurora B is key contributor for the isoform selectivity of the inhibitor. This salt bridge has not been previously detected in the reported crystal structure of Aurora B. These results might provide a crucial basis for the further development of highly potent inhibitors with high selectivity for Aurora A.

Meroterpenoid dimers from Ganoderma cochlear and their cytotoxic and COX-2 inhibitory activities.

(+)- and (-)-Spirocochlealactones A-C (1-3), three pairs of new spiro meroterpenoidal dimeric enantiomers together with one known compound ganodilactone (4), were isolated from the fruiting bodies of Ganoderma cochlear. Their structures including absolute configurations were assigned by using spectroscopic methods and ECD calculations. All the isolated compounds were tested for their COX-2 inhibitory and cytotoxic activities toward human cancer lines (A549, K562, and Huh-7). The results show that all the compounds could inhibit COX-2 with IC50 values in the range of 1.29 to 3.63 µM. In addition, (+)-spirocochlealactone A and (+)-ganodilactone were found to be moderate activities against human cancer cell line A549 with the IC50 values of 7.14 and 9.47 µM, respectively.

Design, Synthesis, and Structure-Activity Relationship Study of 2-Oxo-3,4-dihydropyrimido[4,5- d]pyrimidines as New Colony Stimulating Factor 1 Receptor (CSF1R) Kinase Inhibitors.

Colony stimulating factor 1 receptor kinase (CSF1R) is a well validated molecular target for anticancer drug discovery. Herein, we report the design, synthesis, and structure-activity relationship study of 2-oxo-3,4-dihydropyrimido[4,5- d]pyrimidines as new orally bioavailable CSF1R inhibitors. One of the most promising compounds, 3bw, potently inhibits CSF1R kinase with an IC50 value of 3.0 nM, while it is less potent against structurally related epidermal growth factor receptor (EGFR) and other kinases. The kinase inhibition of 3bw was further validated by Western blotting analysis in RAW264.7 macrophages. The molecule also potently blocks macrophage infiltration, abrogates the protumorigenic influences of macrophages, and exhibits reasonable pharmacokinetic profile. Compound 3bw may serve as a new valuable lead compound for future anticancer drug discovery.