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Highlights • GNF-7, a multi-targeted kinase inhibitor, is highly potent against FGFR4. • GNF-7 and SIJ1263 are highly potent on Ba/F3 cells with wtFGFR4 or mtFGFR4. • GNF-7 and SIJ1263 are highly potent on HCC cells with FGFR4 activation. • GNF-7 and SIJ1263 strongly block FGFR signaling and induce apoptosis in HCC cells. • GNF-7 and SIJ1263 strongly suppress migration/invasion/AIG of HCC cells., Hepatocellular carcinoma (HCC) is disease with a high mortality rate and limited treatment options. Alterations of fibroblast growth factor receptor 4 (FGFR4) has been regarded as an oncogenic driver for HCC and a promising target for HCC therapeutics. Herein, we report that GNF-7, a multi-targeted kinase inhibitor, and its derivatives including SIJ1263 (IC50 < 1 nM against FGFR4) are highly potent FGFR4 inhibitors and are capable of strongly suppressing proliferation of HCC cells and Ba/F3 cells transformed with wtFGFR4 or mtFGFR4. Compared with known FGFR4 inhibitors, both GNF-7 and SIJ1263 possess much higher (up to 100-fold) anti-proliferative activities via FGFR signaling blockade and apoptosis on HCC cells. Especially, SIJ1263 is 80-fold more potent (GI50 = 24 nM) on TEL-FGFR4 V550E Ba/F3 cells than BLU9931, which suggests that SIJ1263 would be effective for overriding drug resistance. In addition, both substances strongly suppress migration/invasion and colony formation of HCC cells. It is worth noting that SIJ1263 is superior to GNF-7 with regards to the fact that activities of SIJ1263 are higher than those of GNF-7 in all assays performed in this study. Collectively, this study provides insight into designing highly potent FGFR4 inhibitors capable of potentially overcoming drug-resistance for the treatment of HCC patients.

BRAF mutants are categorized into three classes according to dependency on RAS signaling and RAF dimerization-dependency. Class I BRAF V600 mutants (RAS-independent monomer) are sensitive to vemurafenib. In contrast, both class II mutants (RAS-independent dimer) and class III mutants (RAS-dependent heterodimer) are insensitive to vemurafenib. It is not likely that BRAF inhibitors capable of inhibiting all classes of BRAF mutants are currently available. Herein, we report GNF-7 and its novel derivative, SIJ1227 as the first BRAF inhibitors capable of inhibiting all classes of BRAF mutants. Compared with vemurafenib and PLX8394, both GNF-7 and SIJ1227 possess much more strong anti-proliferative activities on melanoma (A375 and C8161) and lung cancer cells (H1755 and H1666) harboring BRAF V600E (class I mutant), BRAF G464E/G469A (class II mutant) and BRAF G466V (class III mutant), respectively. Also, both GNF-7 and SIJ1227 are capable of inhibiting more strongly colony formation than vemurafenib and PLX8394 in 3D soft agar assay using C8161 melanoma cells. In addition, GNF-7 and SIJ1227 suppress more strongly migration/invasion of these cancer cells than vemurafenib and PLX8394. Taken together, both GNF-7 and SIJ1227 are much superior to vemurafenib and PLX8394 in terms of capability to inhibit all classes of BRAF mutants.

Aurora kinases play an essential role in mitosis and cell cycle regulation. In recent years Aurora kinases have proved popular cancer targets and many inhibitors have been developed. The majority of these clinical candidates are multi-targeted, rendering them inappropriate as tools for studying Aurora kinase mediated signaling. Here we report discovery of a highly selective inhibitor of Aurora kinases A, B and C, with potent cellular activity and minimal off-target activity (PLK4). The X-ray co-crystal structure of Aurora A in complex with compound 2 is reported, and provides insights into the structural determinants of ligand binding and selectivity.

A highly diastereoselective and efficient convergent synthesis of mupirocin H starting from (+)-(R)-Roche ester was achieved. Grubbs cross metathesis was employed as the key step in the pathway to generate an important E-olefin intermediate. Other processes utilized in the route include a Pd-catalysed stereoselective substitution reaction of a cis epoxide, Sharpless epoxidation followed by Red-Al promoted epoxide ring opening, and Seebach methylation and a TEMPO/BAIB mediated oxidation-lactonization sequence. Finally, we observed that mupirocin H inhibits SbnE, a synthetase required for staphyloferrin B biosynthesis.

Nek9 is a member of the understudied Nek family of dark kinases. Aberrant activation of Nek9 kinase signaling has been linked to poor keratinocyte differentiation phenotypes, and is a key driver of nevus comedonicus, a rare, localized form of acne. Nek9 also has essential scaffolding roles; during mitosis the non-catalytic C-terminal domain of Nek9 binds to Nek6 and Nek7, releasing them from an auto-inhibitory conformation, and enabling proper mitotic progression. Finally, Nek9 expression has been linked to cancer proliferation. SiRNA mediated Nek9 knock-down in a panel of cancer cell lines induces G1 cell cycle arrest and inhibits proliferation when p53 is also inactivated; cell lines with functional p53 are unaffected. Presently, no selective small molecule Nek9 chemical probes are available, though a subset of promiscuous kinase inhibitors have Nek9 activity. Recently described targeted protein degradation approaches have shown that degrader molecules based on multi-targeted kinase inhibitors may effect selective kinase degradation, despite binding to many targets. In this study we report the identification and SAR of potent degraders of the NEK9 kinase that represent attractive leads for further development. Future work is needed to optimize the selectivity of the compounds.

A novel series of arylurea and arylamide derivatives 1a – z , 2a – d having aminoquinazoline scaffold was designed and synthesized. Their in vitro antiproliferative activities against RT112 bladder cancer cell line and inhibitory activities against FGFR3 kinase were tested. Most compounds showed good antiproliferative activities against RT112 bladder cancer cell line, and arylurea compounds 1a – z were more potent than arylamide compounds 2a – d . Among them, eight compounds 1a , 1d – g , 1l , 1y , and 1z showed potent activities with GI 50 values below submicromolar range. Especially, arylurea compounds 1d and 1g possessing 2,3-dimethyl and 3,4-dimethyl moieties exhibited superior or similar antiproliferative activity (GI 50 = 8.8 nM and 30.2 nM, respectively) to AZD4547 (GI 50 = 29.2 nM) as a reference standard.

Recently inhibition of ROS1 kinase has proven to be a promising strategy for several indications such as glioblastoma, non-small cell lung cancer (NSCLC), and cholangiocarcinoma. Our team reported trisubstituted pyrazole-based ROS1 inhibitors by which two inhibitors showed good IC₅₀ values in enzyme-based screening. To develop more advanced ROS1 inhibitors through SAR this trisubstituted pyrazole-based scaffold has been built. Consequently, 16 compounds have been designed, synthesized and shown potent IC₅₀ values in the enzymatic assay, which are from 13.6 to 283 nM. Molecular modeling studies explain how these ROS1 kinase inhibitors revealed effectively the key interactions with ROS1 ATP binding site. Among these compounds, compound 9a (IC₅₀=13.6 nM) has exerted 5 fold potency than crizotinib and exhibited high degree of selectivity (selectivity score value=0.028) representing the number of non-mutant kinases with biological activity over 90% at 10 μM.

The synthesis of the indolizidine alkaloid, (+)-lentiginosine, is described. A key feature of the preparative route is the efficient and stereoselective construction of a dihydroxylated pyrrolidine via Sharpless asymmetric dihydroxylation of an aziridine-enoate, which was prepared from commercially available 1-(S)-α-methylbenzylaziridine-2-methanol. In addition, a regioselective aziridine-to-pyrrolidinone ring expansion process followed by a Wittig olefination was employed to construct a late stage pyrrolidine intermediate that was transformed into (+)-lentiginosine.

The focal adhesion kinase (FAK) signaling cascade in cancer cells was profoundly inhibited by methyl violet 2B identified with the structure-based virtual screening. Methyl violet 2B was shown to be a non-competitive inhibitor of full-length FAK enzyme vs. ATP. It turned out that methyl violet 2B possesses extremely high kinase selectivity in biochemical kinase profiling using a large panel of kinases. Anti-proliferative activity measurement against several different cancer cells and Western blot analysis showed that this substance is capable of suppressing significantly the proliferation of cancer cells and is able to strongly block FAK/AKT/MAPK signaling pathways in a dose dependent manner at low nanomolar concentration. Especially, phosphorylation of Tyr925-FAK that is required for full activation of FAK was nearly completely suppressed even with 1 nM of methyl violet 2B in A375P cancer cells. To the best of our knowledge, it has never been reported that methyl violet possesses anti-cancer effects. Moreover, methyl violet 2B significantly inhibited FER kinase phosphorylation that activates FAK in cell. In addition, methyl violet 2B was found to induce cell apoptosis and to exhibit strong inhibitory effects on the focal adhesion, invasion, and migration of A375P cancer cells at low nanomolar concentrations. Taken together, these results show that methyl violet 2B is a novel, potent and selective blocker of FAK signaling cascade, which displays strong anti-proliferative activities against a variety of human cancer cells and suppresses adhesion/migration/invasion of tumor cells.

An efficient synthesis of (−)-8- epi -swainsonine, starting from a commercially available 1-( R )-α-methylbenzylaziridine-2-methanol, was developed. The synthetic route utilizes stereocontrolled Sharpless asymmetric dihydroxylation governed by AD-mix-β followed by an aziridine ring opening-cyclization sequence to generate the five membered N-heterocyclic ring system present in the bicyclic target. A subsequent stereoselective allylation and piperidine ring forming cyclization then produced a precursor that was converted into (−)-8- epi -swainsonine.

A synthesis of the E-isomer of the proposed structure of the novel tripeptide, lucentamycin A, was performed in an attempt to define the correct stereochemistry of this natural product. The synthetic route developed employs a stereoselective Rh-catalyzed reductive cyclization process to generate the key pyrrolidine residue in the target and a stereospecific inversion of the Z-olefin geometry to form desired E-isomer. Subsequent amide coupling reactions afforded the desired E-isomer of putative lucentamycin A. A comparison of the NMR data of synthetic E-1a with that of the naturally occurring lucentamycin A demonstrated that they are not identical substances and the E-1a was found to display no anti-proliferative activity on the colon cancer cell line HCT-116 in contrast to natural lucentamycin A.

A series of new diarylurea and diarylamide derivatives possessing acet(benz)amidophenyl scaffold was synthesized. Their in vitro antiproliferative activity was tested against A375P human melanoma cell line. Compounds 1c,d and 2c,d showed the highest potencies with IC(50) values in sub-micromolar scale. In addition, compounds 1b,e,l and 2e,l were more potent than Sorafenib but with IC(50) values in micromolar range. Moreover, compound 2c was equipotent to Vemurafenib, and 2d showed higher potency than Vemurafenib against A375P. Molar refractometry calculation and ADME profiling of the highest potent four derivatives 1c,d and 2c,d are also reported.

A Rh-catalyzed diastereoselective reductive cyclization, mediated by hydrogen, of optically active 1,6-enynes using chiral BINAP was successfully applied to the total synthesis of four stereoisomers of the proposed structure of lucentamycin A. In order to synthesize two of these four stereoisomers, we successfully constructed chiral proline derivatives bearing cis -carbon substituents at C2 and C3 positions based on Krische’s methodology, which has very rarely been reported. Anti-proliferative activities on HCT-116 cell line and NMR data of these four stereoisomers were compared with those of naturally occurring lucentamycine A. The results show that the proposed structure of lucentamycin A needs revision.

The mitogen activated kinases JNK1/2/3 are key enzymes in signaling modules that transduce and integrate extracellular stimuli into coordinated cellular response. Here we report the discovery of the first irreversible inhibitors of JNK1/2/3. We describe two JNK3 co-crystal structures at 2.60 and 2.97 Å resolutions that show the compounds form covalent bonds with a conserved cysteine residue. JNK-IN-8 is a selective JNK inhibitor that inhibits phosphorylation of c-Jun, a direct substrate of JNK kinase, in cells exposed to sub-micromolar drug in a manner that depends on covalent modification of the conserved cysteine residue. Extensive biochemical, cellular and pathway-based profiling establish the selectivity of JNK-IN-8 for JNK and suggest that the compound will be broadly useful as a pharmacological probe of JNK-dependent signal transduction. Potential lead compounds have also been identified for kinases including IRAK1, PIK3C3, PIP4K2C, and PIP5K3.

Synthesis of a new series of diarylureas and diarylamides having 1 H -pyrrolo[3,2- c ]pyridine scaffold is described. Their in vitro antiproliferative activity against A375P human melanoma cell line was tested and the effect of substituents on pyrrolo[3,2- c ]pyridine nucleus was investigated. The newly synthesized compounds, except three N -tolyl derivatives ( 8f , 9f , and 9h ), generally showed superior activity against A375P to Sorafenib. Among all of these derivatives, compounds 8b , 8g , and 9a–e showed the highest potency against A375P with IC 50 in nanomolar range. In addition, compounds 8d , 8e , 8h , 9g , 9i , and 9j were more potent than Sorafenib but with IC 50 in micromolar range. Compounds 8b , 8g , 9b–d , and 9i demonstrated higher selectivity towards A375P compared with NIH3T3 fibroblasts. The most potent diarylurea 8g and diarylamide 9d were further tested and showed high potency over nine melanoma cell lines at the NCI.

The synthesis of a novel series of aminoquinazoline derivatives 1a-r and their antiproliferative activities against A375 human melanoma cell line were described. Among them, six compounds showed superior antiproliferative activities to Sorafenib as a reference compound. In particular, the representative compound 1q bearing chromen-4-one moiety exhibited excellent antiproliferative activity (IC(50)=0.006 μM) and good selectivity over HS27 fibroblast cell line.

Naturally occurring L-783277 which belongs to 14-membered resorcylic acid lactones (RALs) turned out to be a potent kinase inhibitor against MEK (MAP kinase kinase). We successfully accomplished efficient and enantioselective total synthesis of L-783277 based on convergent assembly of one aromatic unit and two chiral building blocks with efficient orthogonal protection-deprotection strategy. Three key steps composed of olefin cross metathesis, addition of acetylene derivative to aldehyde, and Yamaguchi macrolactonization were subsequently employed to construct the framework of L-783277. The optical rotation value of L-783277 is for the first time presented in this Letter.

Synthesis of a new series of diarylureas and amides having pyrrolo[3,2-b]pyridine scaffold is described. Their in vitro antiproliferative activity against human melanoma cell line A375 and HS 27 human fibroblast cell line was tested and the effect of substituents on the pyrrolo[3,2-b]pyridine was investigated. The newly synthesized compounds, except meta-substituted derivatives (Ij-k and Iv-w), generally showed superior or similar activity against A375 to Sorafenib. Among all of these derivatives, compounds Ir and It having 5-benzylamide substituted 4'-amide moieties showed the most potent antiproliferative activity against A375.

Synthesis of a new series of diarylureas and amides having pyrrolo[2,3-d]pyrimidine scaffold is described. Their in vitro antiproliferative activities against A375 human melanoma cell line and HS 27 fibroblast cell line were tested and the effect of substituents on pyrrolo[2,3-d]pyrimidine was investigated. The newly synthesized compounds, except N-acetyl derivatives (Id, Ie, and Im), generally showed superior or similar activity against A375 to Sorafenib. Among all of these derivatives, compounds Iq and Ir having imidazole and morpholine moieties, respectively, showed the most potent antiproliferative activity against A375.

A series of 4-amino-6-benzimidazole-pyrimidines was designed to target lymphocyte-specific tyrosine kinase (Lck), a member of the Src-family kinases (SFKs). These type II inhibitors were optimized using a cellular Lck-dependent proliferation assay and are capable of inhibiting Lck at single-digit nanomolar concentrations. This scaffold is likely to serve a valuable template for developing potent inhibitors of a number of SFKs.

Allosteric kinase inhibitors hold promise for revealing unique features of kinases that may not be apparent using conventional ATP-competitive inhibitors. Here we explore the activity of a previously reported allosteric inhibitor of BCR-Abl kinase, GNF-2, against two cellular isoforms of Abl tyrosine kinase: one that carries a myristate in the N terminus and the other that is deficient in N-myristoylation. Our results show that GNF-2 inhibits the kinase activity of non-myristoylated c-Abl more potently than that of myristoylated c-Abl by binding to the myristate-binding pocket in the C-lobe of the kinase domain. Unexpectedly, indirect immunofluorescence reveals a translocation of myristoylated c-Abl to the endoplasmic reticulum in GNF-2-treated cells, whereas GNF-2 has no detectable effect on the localization of non-myristoylated c-Abl. These results indicate that GNF-2 competes with the NH(2)-terminal myristate for binding to the c-Abl kinase myristate-binding pocket and that the exposed myristoyl group accounts for the localization to the endoplasmic reticulum. We also demonstrate that GNF-2 can inhibit enzymatic and cellular kinase activity of Arg, a kinase highly homologous to c-Abl, which is also likely to be regulated through intramolecular binding of an NH(2)-terminal myristate lipid. These results suggest that non-ATP-competitive inhibitors, such as GNF-2, can serve as chemical tools that can discriminate between c-Abl isoform-specific behaviors.

The synthesis of a novel series of aminoquinoline derivatives 1a–p and their antiproliferative activities against A375 human melanoma cell line were described. Most compounds showed superior antiproliferative activities to Sorafenib as a reference compound. Among them, quinolinyloxymethylphenyl compounds 1k and 1l exhibited potent activities (IC50 = 0.77 and 0.79 μM, respectively) and excellent selectivity against melanoma and fibroblast cell lines.

A series of 4-amino-6-benzimidazole-pyrimidines was designed to target lymphocyte-specific tyrosine kinase (Lck), a member of the Src kinase family. Highly efficient parallel syntheses were devised to prepare analogues for SAR studies. A number of these 4-amino-6-benzimidazole-pyrimidines exhibited single-digit nanomolar IC50s against Lck in biochemical and cellular assays. These 4-amino-6-benzimidazole-pyrimidines represent a new class of tyrosine kinase inhibitors.

A highly efficient method for the synthesis of 1,4-dideoxy-1,4-imino- d - and l -arabinitol ( d -AB1, 1 and l -AB1, 3 ) and 1,4-dideoxy-1,4-imino- d - and l -xylitol ( d -DIX, 2 and l -DIX, 4 ) starting from commercially available chiral aziridines was developed. The general strategy employs a sequence involving two-carbon homologation, dihydroxylation, and regioselective aziridine ring opening/intramolecular five-membered iminosugar ring formation. The facile use of recrystallization to generate pure diastereomers makes the routes more amenable to large-scale synthesis.

Reliable technologies for addressing target identification and validation are the foundation of successful drug development. Microarrays have been well utilized in genomics/proteomics approaches for gene/protein expression profiling and tissue/cell-scale target validation. Besides being used as an essential step in analyzing high-throughput experiments such as those involving microarrays, bioinformatics can also contribute to the processes of target identification and validation by providing functional information about target candidates and positioning information to biological networks. Antisense technologies (including RNA interference technology, which is recently very 'hot') enable sequence-based gene knockdown at the RNA level. Zinc finger proteins are a DNA transcription-targeting version of knockdown. Chemical genomics and proteomics are emerging tools for generating phenotype changes, thus leading to target and hit identifications. NMR-based screening, as well as activity-based protein profiling, are trying to meet the requirement of high-throughput target identification.

A facile one-step transformation of methylsulfanyl and arylsulfanyl groups on pyrimidine ring system into the corresponding chloride group was achieved using sulfuryl chloride in acetonitrile/dichloromethane.

Alkyl iodides can be coupled with α,β-unsaturated esters using Ni2B(0.05–0.2 eq)-BER(3 eq) in methanol at room temperature. Products (68–95%) are conveniently isolated, simply filtering the resin and evaporating the excess enoates and methanol.