TrkA kinase inhibitors from a library of modified and isosteric Staurosporine aglycone

Ligand-based computer aided drug design reveals new tropomycin receptor kinase a (TrkA) inhibitors

Targeting tropomycin kinase A (TrkA) by small molecule inhibitors is considered as a promising strategy for treating several human cancers. To achieve this goal, a ligand based QSAR model was applied using the Discovery studio 4.5 (DS 4.5). Hence, a total list of 161 TrkA inhibitors was investigated. The TrkA inhibitors were extensively explored to detect their optimal physicochemical properties and pharmacophoric binding modes, which were converted into numeric descriptors and allowed to compete within the context of the Genetic Function Algorithm (GFA) approximations to find the subset of terms that correlates best with the activity. The resulted successful QSAR equation had statistical criteria of (r²₁₂₉=0.67, r²_LOO=0.61 r²_PRESS against 32 external test inhibitors=0.50). Afterwards, the most successful pharmacophore: HypoB-T5-3, was used to screen compounds within the National Cancer institute (NCI) database. Only 41 compounds were retrieved and 21 of them exhibited anti-TrkA activity. The most potent hit had an IC₅₀ value of 2.4μM. Later, upon docking the active hits into the TrkA binding pocket, important interactions were revealed including hydrogen bonding with the amino acids Asp668 and Lys544 in addition to the cation-π interactions with the sidechain of Arg559.

Synthesis of N-(Hetero)aryl Carbamates via CuI/MNAO Catalyzed Cross-Coupling of (Hetero)aryl Halides with Potassium Cyanate in Alcohols

An efficient route to N-(hetero)aryl carbamates was developed through CuI/MNAO [2-((2-methylnaphthalen-1-yl)amino)-2-oxoacetic acid] catalyzed cross-coupling of (hetero)aryl chlorides with potassium cyanate in alcohols at 120-130 °C. This method utilizes broadly available substrates to afford various N-(hetero)aryl carbamates in good to excellent yields. Moreover, (hetero)aryl bromides and (hetero)aryl iodides were also reacted at low catalyst loadings and relatively low temperatures to provide N-(hetero)aryl carbamates.

Discovery of wrightiadione as a novel template for the TrkA kinase inhibitors

Enzymatic kinase assays and docking simulation studies have shown that the natural product wrightiadione displays inhibitory activity toward TrkA and PLK3. In this study, the template of wrightiadione served as a starting point for Trk inhibitor development campaigns. Molecular simulation provided structural insights for the design of derivatives that were efficiently generated by our recently developed 3-step tandem synthetic approach, resulting in the discovery of compound 2h with biochemical potency at the single-digit micromolar level.

Identification of pyrazine-based TrkA inhibitors: design, synthesis, evaluation, and computational modeling studies

Trk receptors play a key role in the development and maintenance of neuronal networks. Recent evidence suggests that the Trk family, specifically TrkA, is an important driver for tumour growth, inflammatory and neuropathic pain, and chemoresistance. Through a computational screen, a novel Trk active pharmacophore was identified and a series of pyrazine-based inhibitors were developed, which potently inhibited TrkA. Inhibitors displayed the highest activity on TrkA when screened against a small, tyrosine kinase panel and also exhibited a non-linear SAR. Predicted binding modes of the inhibitors were examined, which identified exploitable regions for future development of more advanced inhibitors.

Indenoindoles and cyclopentacarbazoles as bioactive compounds: synthesis and biological applications

Indenoindoles and their isomers cyclopentacarbazoles represent a wide class of synthetic and natural compounds. The great interest of these structures in (bio)organic chemistry is due to the use of various building blocks to get the elemental four ring structure. Depending on the synthetic route chosen, the chemists can achieve a large number of regioisomers. Each regioisomer can be considered as a template for specific functionalizations. Therefore, this mini-review aims (i) to present an overview on how to access this large family of heterocyclic compounds and (ii) to discuss their various biological applications and drug development in oncology (e.g. kinases), in CNS disorders (e.g. Alzheimer's disease), in endocrinology (e.g. hormone replacement therapy) and oxidative stress (e.g. organ preservation). Past and present works will be presented through the systems 6-5-5-6 and 6-5-6-5 (combination of 6-membered and 5-membered rings).

Identification of a Novel Series of Potent TrkA Receptor Tyrosine Kinase Inhibitors

A novel series of N-(3-(6-substituted-aminopyridin-3-yloxy)phenyl)-2-oxo-3-phenylimidazolidine-1-carboxamides targeting TrkA receptor tyrosine kinase was identified. SAR study of the series allowed us to design and synthesize compounds possessing inhibitory activity of TrkA kinase enzyme in the low nanomolar range with low residual activity against c-Met and with no significant activity against VEGFR2.

Identification of novel inhibitors of tropomyosin-related kinase A through the structure-based virtual screening with homology-modeled protein structure

Tropomyosin-related kinase A (TrkA) is a promising target for the development of cancer and pain therapeutics. Here, we report the first successful example of the use of a structure-based virtual screening to identify novel TrkA inhibitors. The accuracy of the virtual screening was improved by introducing an accurate solvation free energy term into the original AutoDock scoring function. We applied a drug design protocol involving homology modeling, docking analysis of a large chemical library, and enzyme inhibition assays to identify six structurally diverse TrkA inhibitors with K(d) values ranging from 3 to 40 μM. The significant potencies and good physicochemical properties of these drug candidates strongly support their consideration in a development effort that would involve structure-activity relationship (SAR) studies to optimize the inhibitory activities. We also addressed the structural and energetic features associated with binding of the newly identified inhibitors in the ATP-binding site of TrkA. The results indicate that any structural modifications introduced for the purpose of enhancing the activity of TrkA inhibitors should maximize the attractive interactions within the ATP-binding site and simultaneously minimize the desolvation cost for complexation.

Trk kinase inhibitors as new treatments for cancer and pain

BACKGROUND

Tropomyosin-related kinases (Trks) are a family of receptor tyrosine kinases activated by neurotrophins. Trks play important roles in pain sensation as well as tumour cell growth and survival signaling. Thus, inhibitors of Trk receptor kinases might provide targeted treatments for pain and cancer.

OBJECTIVE

This paper reviews those patent applications since 2002 claiming small-molecule inhibitors of Trk receptor kinases.

METHODS

Primary literature and patents were searched with SciFinder and Google Scholar. Patents were selected based on their relevance to Trks and were evaluated and representative compounds were listed as examples.

RESULTS/CONCLUSION

Several series of Trk inhibitors with excellent in vitro potencies have been reported and a number of compounds have gone into the clinic. It should be noted that few of these inhibitors are Trk selective, demonstrating that targeting Trk kinases for treatment of pain and/or cancer offers a promising but also challenging approach.