Inhibitor repurposing reveals ALK, LTK, FGFR, RET and TRK kinases as the targets of AZD1480

Discovery of 9H-pyrimido[4,5-b]indole derivatives as dual RET/TRKA inhibitors

Aberrant RET kinase signaling is activated in numerous cancers including lung, thyroid, breast, pancreatic, and prostate. Recent approvals of selective RET inhibitors, pralsetinib and selpercatinib, has shifted the focus of RET kinase drug discovery programs towards the development of selective inhibitors. However, selective inhibitors invariably lose efficacy as the selective nature of the inhibitor places Darwinian-like pressure on the tumor to bypass treatment through the selection of novel oncogenic drivers. Further, selective inhibitors are restricted for use in tumors with specific genetic backgrounds that do not encompass diverse patient classes. Here we report the identification of a pyrimido indole RET inhibitor found to also have activity against TRK. This selective dual RET/TRK inhibitor can be utilized in tumors with both RET and TRK genetic backgrounds and can also provide blockade of NTRK-fusions that are selected for from RET inhibitor treatments. Efforts towards developing dual RET/TRK inhibitors can be beneficial in terms of encompassing more diverse patient classes while also achieving blockade against emerging resistance mechanisms.

The Application of Artificial Intelligence and Drug Repositioning for the Identification of Fibroblast Growth Factor Receptor Inhibitors: A Review

Artificial intelligence talks about modeling intelligent behavior through a computer with the least human involvement. Drug repositioning techniques based on artificial intelligence accelerate the research process and decrease the cost of experimental studies. Dysregulation of fibroblast growth factor (FGF) receptors as the tyrosine kinase family of receptors plays a vital role in a wide range of malignancies. Because of their functional significance, they were considered promising drug targets for the therapy of various cancers. This review has summarized small molecules capable of inhibiting FGF receptors that progressed using artificial intelligence and repositioning drugs examined in clinical trials associated with cancer therapy. This review is based on a literature search in PubMed, Web of Science, Scopus EMBASE, and Google Scholar databases to gather the necessary information in each chapter by employing keywords like artificial intelligence, computational drug design, drug repositioning, and FGF receptor inhibitors. To achieve this goal, a spacious literature review of human studies in these fields-published over the last 20 decades-was performed. According to published reports, nonselective FGF receptor inhibitors can be used for cancer management, and multitarget kinase inhibitors are the first drug class approved due to more advanced clinical studies. For example, AZD4547 and BGJ398 are gradually entering the consumption cycle and are good options as combined treatments. Artificial intelligence and drug repositioning methods can help preselect suitable drug targets more successfully for future inhibition of carcinogenicity.

Anti-Tumor Activity of AZD4547 Against NTRK1 Fusion Positive Cancer Cells Through Inhibition of NTRKs

Inhibitors of tropomyosin-related kinases (TRKs) display remarkable outcomes in the regression of cancers harboring the Neurotrophin Receptors Tyrosine Kinase (NTRK) fusion gene. As a result, TRKs have become attractive targets in anti-cancer drug discovery programs. Here, we demonstrate that AZD4547, a highly potent and selective inhibitor of fibroblast growth factor receptor (FGFR), displays anti-tumor activity against KM12(Luc) harboring the TPM3-NTRK1 fusion gene associated with its direct inhibition of TRKs. The results of profiling, using a 64-member in-house cancer cell panel, show that AZD4547 displays anti-proliferation activity against KM12(Luc) with a GI₅₀ of 100 nM. In vitro biochemical assays reveal that AZD4547 has IC₅₀ values of 18.7, 22.6 and 2.9 nM against TRKA, B and C, respectively. In a cellular context, AZD4547 blocks auto-phosphorylation of TRKs and phosphorylation of its downstream molecules including PLC-gamma and AKT in a dose dependent manner. Also, AZD4547 at 0.1 μM concentration downregulates expression of MAPK target genes (DUSP6, CCND1 and ETV1) as well as the E2F pathway. Furthermore, AZD4547 induces G0/G1 arrest and apoptosis, and suppresses anchorage independent growth of KM12(Luc). Oral administration of 40 mpk AZD4547 dramatically delays tumor growth in a KM12(Luc) implemented xenograft model, without promoting body weight changes. The capability of AZD4547 to inhibit TRKA, TRKB and clinically relevant mutants (TRKA G595R, G667S, G667C and G667A) was also evaluated using Ba/F3 cells harboring the ETV6-NTRKs fusion gene. The combined observations demonstrate the potential application of AZD4547 for treatment of NTRK fusion driven cancers.

Pyrazoloadenine Inhibitors of the RET Lung Cancer Oncoprotein Discovered by a Fragment Optimization Approach

A fragment-based drug-discovery approach was used on a pyrazoloadenine fragment library to uncover new molecules that target the RET (REarranged during Transfection) oncoprotein, which is a driver oncoprotein in ∼2 % of non-small-cell lung cancers. The fragment library was screened against the RET kinase and LC-2/ad (RET-driven), KM-12 (TRKA-driven matched control) and A549 (cytotoxic control) cells to identify selective scaffolds that could inhibit RET-driven growth. An unsubstituted pyrazoloadenine fragment was found to be active on RET in a biochemical assay, but reduced cell viability in non-RET-driven cell lines (EC₅₀ =1 and 3 μM, respectively). To increase selectivity for RET, the pyrazoloadenine was modeled in the RET active site, and two domains were identified that were probed with pyrazoloadenine fragment derivatives to improve RET affinity. Scaffolds at each domain were merged to generate a novel lead compound, 8 p, which exhibited improved activity and selectivity for the RET oncoprotein (A549 EC₅₀ =5.92 μM, LC-2/ad EC₅₀ =0.016 μM, RET IC₅₀ =0.000326 μM).

Comparative Genomics within and across Bilaterians Illuminates the Evolutionary History of ALK and LTK Proto-Oncogene Origination and Diversification

Comparative genomic analyses have enormous potential for identifying key genes central to human health phenotypes, including those that promote cancers. In particular, the successful development of novel therapeutics using model species requires phylogenetic analyses to determine molecular homology. Accordingly, we investigate the evolutionary histories of anaplastic lymphoma kinase (ALK)—which can underlie tumorigenesis in neuroblastoma, nonsmall cell lung cancer, and anaplastic large-cell lymphoma—its close relative leukocyte tyrosine kinase (LTK) and their candidate ligands. Homology of ligands identified in model organisms to those functioning in humans remains unclear. Therefore, we searched for homologs of the human genes across metazoan genomes, finding that the candidate ligands Jeb and Hen-1 were restricted to nonvertebrate species. In contrast, the ligand augmentor (AUG) was only identified in vertebrates. We found two ALK-like and four AUG-like protein-coding genes in lamprey. Of these six genes, only one ALK-like and two AUG-like genes exhibited early embryonic expression that parallels model mammal systems. Two copies of AUG are present in nearly all jawed vertebrates. Our phylogenetic analysis strongly supports the presence of previously unrecognized functional convergences of ALK and LTK between actinopterygians and sarcopterygians—despite contemporaneous, highly conserved synteny of ALK and LTK. These findings provide critical guidance regarding the propriety of fish and mammal models with regard to model organism-based investigation of these medically important genes. In sum, our results provide the phylogenetic context necessary for effective investigations of the functional roles and biology of these critically important receptors.