Tyrosine Kinase Domain Research Articles

Saturation profiling of drug-resistant genetic variants using prime editing.

Methods to characterize the functional effects of genetic variants of uncertain significance (VUSs) have been limited by incomplete coverage of the mutational space. In clinical oncology, drug resistance arising from VUSs can prevent optimal treatment. Here we introduce PEER-seq, a high-throughput method based on prime editing that can evaluate the functional effects of single-nucleotide variants (SNVs). PEER-seq introduces both intended SNVs and synonymous marker mutations using prime editing and deep sequences the endogenous target regions to identify the introduced SNVs. We generate and functionally evaluate 2,476 SNVs in the epidermal growth factor receptor gene (EGFR), including 99% of all possible variants in the canonical tyrosine kinase domain. We determined resistance profiles of 95% of all possible EGFR protein variants encoded in the whole tyrosine kinase domain against the common tyrosine kinase inhibitors afatinib, osimertinib and osimertinib in the presence of the co-occurring substitution T790M, in PC-9 cells. Our study has the potential to substantially improve the precision of therapeutic choices in clinical settings.

Common epidermal growth factor receptor mutations in north Indian patients with non-small cell lung carcinoma: evidence from real-time polymerase chain reaction.

Lung carcinoma was the ace cause of cancer deaths globally in 2022, with non-small cell lung carcinoma (NSCLC) accounting for 81% of the burden. Due to promising tyrosine kinase inhibitor (TKI) trials, NSCLC patients harboring epidermal growth factor receptor (EGFR) gene mutations are of interest. Our aim was to determine EGFR mutation prevalence in north India and its histologic and demographic correlations. We investigated the frequency of EGFR mutations in 40 patients with histologically confirmed NSCLC using real-time polymerase chain reaction. A 15% mutation frequency was observed in the study sample, involving 32 males and 8 females with a median age of 59 years. Squamous cell carcinoma (SCC) patients had only EXON20 (T790M, exon20 insertion) mutations, while adenocarcinoma patients had mutations in both EXON20 (T790M) and 21 (L858R) with mutation frequencies of 22% and 10%, respectively. 28% of the SCC patients were non-smokers, and 60% of these non-smokers had an EGFR mutation. South Indian and Asian studies have identified EXON19 (19-Del) and EXON21 (L858R) mutations as "common mutations" that account for nearly 80-90% of all mutations and respond well to TKIs. Interestingly, "common mutations" were found seldom in our study population, while the uncommon variants constitute 83% of all mutations, which we assume is due to diverse Indian genetics and ethnicity and co-existing signature mutations that involve the tyrosine kinase domain of EXON20. We suggest future genome-wide association studies to identify plausible genetic polymorphisms responsible for interethnic differences in EGFR mutation, which will contribute to better treatment and prevention of NSCLCs.

Midostaurin shapes macroclonal and microclonal evolution of FLT3-mutated acute myeloid leukemia

AbstractDespite the use of midostaurin (MIDO) with intensive chemotherapy (ICT) as the frontline treatment for Fms-like tyrosine kinase 3 (FLT3)-mutated acute myeloid leukemia (AML), complete remission rates are close to 60% to 70%, and relapses occur in >40% of cases. Here, we studied the molecular mechanisms underlying refractory/relapsed (R/R) disease in patients with FLT3-mutated AML. We conducted a retrospective and multicenter study involving 150 patients with R/R AML harboring FLT3–internal tandem duplication (ITD) (n = 130) and/or FLT3–tyrosine kinase domain (n = 26) at diagnosis assessed by standard methods. Patients were treated in front line with ICT + MIDO (n = 54) or ICT alone (n = 96) according to the diagnosis date and label of MIDO. The evolution of FLT3 clones and comutations was analyzed in paired diagnosis–R/R samples by targeted high-throughput sequencing. Using a dedicated algorithm for FLT3-ITD detection, 189 FLT3-ITD microclones (allelic ratio [AR] of <0.05) and 225 macroclones (AR ≥ 0.05) were detected at both time points. At R/R disease, the rate of FLT3-ITD persistence was lower in patients treated with ICT + MIDO than in patients not receiving MIDO (68% vs 87.5%; P = .011). In patients receiving ICT + MIDO, detection of multiple FLT3-ITD clones (referred to as “clonal interference”) was associated with a higher FLT3-ITD persistence rate at R/R disease (multiple clones: 88% vs single clones: 57%; P = .049). Considering both treatment groups, if only 24% of FLT3-ITD microclones detected at diagnosis were retained at relapse, 43% became macroclones. Together, these results identify parameters influencing the fitness of FLT3-ITD clones and highlight the importance of using sensitive techniques for FLT3-ITD screening in clinical practice.

Spontaneous Dimerization and Distinct Packing Modes of Transmembrane Domains in Receptor Tyrosine Kinases.

The insulin receptor (IR) and the insulin-like growth factor-1 receptor (IGF1R) are homodimeric transmembrane glycoproteins that transduce signals across the membrane on binding of extracellular peptide ligands. The structures of IR/IGF1R fragments in apo and liganded states have revealed that the extracellular subunits of these receptors adopt Λ-shaped configurations to which are connected the intracellular tyrosine kinase (TK) domains. The binding of peptide ligands induces structural transitions in the extracellular subunits leading to potential dimerization of transmembrane domains (TMDs) and autophosphorylation in TKs. However, the activation mechanisms of IR/IGF1R, especially the role of TMDs in coordinating signal-inducing structural transitions, remain poorly understood, in part due to the lack of structures of full-length receptors in apo or liganded states. While atomistic simulations of IR/IGF1R TMDs showed that these domains can dimerize in single component membranes, spontaneous unbiased dimerization in a plasma membrane having a physiologically representative lipid composition has not been observed. We address this limitation by employing coarse-grained (CG) molecular dynamics simulations to probe the dimerization propensity of IR/IGF1R TMDs. We observed that TMDs in both receptors spontaneously dimerized independent of their initial orientations in their dissociated states, signifying their natural propensity for dimerization. In the dimeric state, IR TMDs predominantly adopted X-shaped configurations with asymmetric helical packing and significant tilt relative to the membrane normal, while IGF1R TMDs adopted symmetric V-shaped or parallel configurations with either no tilt or a small tilt relative to the membrane normal. Our results suggest that IR/IGF1R TMDs spontaneously dimerize and adopt distinct dimerized configurations.

Efficacy of immune checkpoint inhibitors plus platinum-based chemotherapy as 1st line treatment for patients with non-small cell lung cancer harboring HER2 mutations: Results from LC-SCRUM-Asia

IntroductionHER2 mutations are reported to occur in 2%–5% of all cases of non-small cell lung cancer (NSCLC). The clinical outcomes in patients with HER2-mutant NSCLC treated with immune checkpoint inhibitors (ICIs) plus platinum-based chemotherapy as 1st line treatment still remain unclear. MethodsUsing the large-scale clinico-genomic database of LC-SCRUM-Asia, the clinico-genomic characteristics and therapeutic outcomes of patients with HER2-mutant NSCLC were investigated. ResultsOf the 15,251 patients with NSCLC enrolled in the LC-SCRUM-Asia database, tumor HER2 mutations were detected in 402 patients (2.6 %). The most common subtype of HER2 mutations was exon 20 in-frame insertions (79 %), followed in frequency by mutations in the tyrosine kinase domain other than Exon20ins (10 %) and mutations in extracellular domains (7 %). NSCLCs harboring HER2 mutations showed a higher tumor mutation burden (TMB) as compared with NSCLCs harboring EGFR mutations or ALK fusions (median: 4.22 vs. 2.54 and 2.52 mutation per megabase, respectively). Of the 402 patients, 268 patients had received platinum-based chemotherapy with ICIs (Chemo-ICI, n = 95) or without ICI (Chemo-alone, n = 173) as 1st line treatment. The progression-free survival (PFS) was significantly longer in the Chemo-ICI group as compared with the Chemo-alone group (median 8.5 vs. 6.3 months; HR [95 %CI]: 0.66 [0.50–0.88]; P < 0.005). Multivariate analysis identified use of ICIs in addition to platinum-based chemotherapy as an independent favorable prognostic factor for PFS. There was no significant difference in the overall survival between the patients of the Chemo-ICI and Chemo-alone groups (median 31.1 vs. 23.3 months; HR [95 %CI]: 0.80 [0.57–1.12], P = 0.20). ConclusionsAddition of ICIs to platinum-based chemotherapy in 1st line treatment may improve the PFS in patients with HER2-mutant NSCLC. The relatively high TMB might be involved in the prolongation of the PFS in patients with HER2-mutant NSCLC receiving platinum-based chemotherapy with ICIs.

Cellular Mechanisms of RET Receptor Dysfunction in Multiple Endocrine Neoplasia 2.

REarranged during Transfection (RET) is a developmentally important receptor tyrosine kinase that has been identified as an oncogenic driver in a number of cancers. Activating RET point-mutations give rise to the inherited cancer syndrome Multiple Endocrine Neoplasia type 2 (MEN2), characterized by medullary thyroid carcinoma. There are two MEN2 subtypes, MEN2A and MEN2B, that differ in tumour aggressiveness and the associated constellation of other disease features, which are caused by distinct patterns of RET amino acid substitution mutations. MEN2A-RET mutations affecting extracellular cysteine residues promote ligand independent dimerization and constitutive RET activity, while MEN2B is caused by a single amino acid change in the tyrosine kinase domain of RET, releasing autoinhibition and producing a more active MEN2B-RET kinase that can promote signalling as monomers or dimers in the absence of ligand. These mutations cause intrinsic biochemical changes in RET structure and activation but also trigger extrinsic effects that alter RET cellular location, interactions and mechanisms of downregulation that can prolong or mislocate RET activity, changing or enhancing functional outcomes. Together, changes in specific combinations of RET-mediated effects associated with different mutations give rise to the distinct MEN2 disease phenotypes. Here, we discuss the current understanding of the intrinsic and extrinsic characteristics of RET MEN2A cysteine and MEN2B mutants and how these contribute to transforming cellular processes and to differences in tumour progression and disease aggressiveness.

Safety, Efficacy and Biomarker Analysis of Crizotinib in MET Mutated Non-Small Cell Lung Cancer - Results from the Drug Rediscovery Protocol.

MET mutations occur in 3-4% of advanced non-small cell lung cancer (aNSCLC), correlating with poor survival. Despite known sensitivity of MET mutated (METmut) aNSCLC to c-MET-inhibition, no approved therapies existed until 2022. In the Drug Rediscovery Protocol (NCT0295234), patients with an actionable molecular profile are treated with off-label registered drugs. Both treated and untreated patients with aNSCLC harboring MET exon 14 skipping (METex14) or other METmuts received crizotinib 250 mg BID until disease progression or intolerable toxicity. Primary endpoints were clinical benefit (CB: RECIST v1.1 confirmed partial response (PR), complete response (CR) or stable disease (SD) ≥16 weeks) and safety. Patients were enrolled using a Simon-like two-stage design, with eight patients in stage 1 and if ≥1/8 patients had CB, 24 patients in stage 2. Whole genome and RNA-sequencing were performed on baseline biopsies. Between 09/2018 and 10/2022, 30 patients started treatment, and 24 were response-evaluable after completing ≥1 full treatment cycle. Two patients (8.3%) achieved CR, thirteen (54.2%) PR and two (8.3%) SD. The CB-rate was 70.8% (95%CI 48.9-87.4) and the objective response rate was 62.5% (95%CI 40.6-81.2). After 21.2 months median follow-up, median duration of response, progression-free and overall survival were 9.3 (95%CI 6.5-NA), 10.2 (95%CI 6.0-20.1) and 13.0 months (95%CI 9.0-NA), respectively. Twenty-three treatment-related grade ≥3 adverse events occurred in 12/30 patients (40%), causing treatment-discontinuation in three (10%). One patient (achieving CR) had a tyrosine kinase domain mutation (p.H1094Y), all other patients had METex14. Crizotinib is a valuable treatment option in METmut aNSCLC.

Anticancer activity, DFT calculation, ADMET study and molecular docking of synthetic Chalcone (2E)-1-(4-Aminophenyl)-3-(3,4,5-trimethoxyphenyl)-2- propen-1-one in breast cancer cell line (MCF-7)

The (2E)-1-(4-Aminophenyl)-3-(3,4,5-trimethoxyphenyl)-2-propen-1-one was prepared by the reaction between 4-aminoacetophenone and 3,4,5, trimethoxy benzaldehyde in ethanolic NaOH. Then in vitro anticancer activity was evaluated against the MCF-7 breast cell line. The molecular properties like bond length, bond angle, molecular electrostatic potential surface (MEPs), Mullikan charge, HOMO-LUMO, and NBO analysis data obtained by DFT/B3LYP method using 6- 31+G(d,p) basis set to get electronic states and molecular parameters of the title molecule. Because of their advantageous pharmacokinetic properties, the synthesized compound was shown to have moderate anticancer activity and could advance to a higher level of the drug development process. Molecular docking studies were utilized to foresee the binding interactions of the title compound with the EGFR tyrosine kinase domain (PDB ID: 1M17). In silico ADME study is also performed to predict the pharmacokinetic profile which expressed good oral drug-like behavior.

Conserved regulatory motifs in the juxtamembrane domain and kinase N-lobe revealed through deep mutational scanning of the MET receptor tyrosine kinase domain.

MET is a receptor tyrosine kinase (RTK) responsible for initiating signaling pathways involved in development and wound repair. MET activation relies on ligand binding to the extracellular receptor, which prompts dimerization, intracellular phosphorylation, and recruitment of associated signaling proteins. Mutations, which are predominantly observed clinically in the intracellular juxtamembrane and kinase domains, can disrupt typical MET regulatory mechanisms. Understanding how juxtamembrane variants, such as exon 14 skipping (METΔEx14), and rare kinase domain mutations can increase signaling, often leading to cancer, remains a challenge. Here, we perform a parallel deep mutational scan (DMS) of the MET intracellular kinase domain in two fusion protein backgrounds: wild-type and METΔEx14. Our comparative approach has revealed a critical hydrophobic interaction between a juxtamembrane segment and the kinase ⍺C-helix, pointing to potential differences in regulatory mechanisms between MET and other RTKs. Additionally, we have uncovered a β5 motif that acts as a structural pivot for the kinase domain in MET and other TAM family of kinases. We also describe a number of previously unknown activating mutations, aiding the effort to annotate driver, passenger, and drug resistance mutations in the MET kinase domain.

Conserved regulatory motifs in the juxtamembrane domain and kinase N-lobe revealed through deep mutational scanning of the MET receptor tyrosine kinase domain

Conserved regulatory motifs in the juxtamembrane domain and kinase N-lobe revealed through deep mutational scanning of the MET receptor tyrosine kinase domain

Potentilla fulgens Wall. Ex sims. Upregulates insulin receptor substrate 1 and Akt in alloxan-induced diabetic mice

BackgroundPotentilla fulgens Wall. ex Sims. is a medicinal plant used by the locals of Meghalaya. However, its mechanism of action has not been well elucidated. Hence, this study investigated the effect of P. fulgens on IRS1 and Akt. The interaction of the various polyphenols present in P. fulgens with the IR tyrosine kinase and IRS1 PTB domain was studied using auto dock. Changes in expression of antioxidant enzymes, IRS-1, Akt and behavior of normal, diabetic, and diabetic mice treated mice were assessed after 14 days of treatment. Morphological changes in the liver tissue were determined by Transmission Electron Microscopy.ResultsThe effect of P. fulgens on blood glucose was time and dose dependent. Treatment with P. fulgens, Cat, E, CE, CEP and metformin improved the activity of catalase, glutathione peroxidase, glycogen, IRS-1 and Akt. The Forced Swimming test showed an altered behavior in diabetic mice. The altered mobility was reverted back to near normal on treatment with P.fulgens, Cat, E, CE, CEP and metformin. The morphological aberrations seen in diabetic animals considerably improved in the treated diabetic group.ConclusionP. fulgens and its phytochemicals-catechin and epicatechin are potent sources of antidiabetic drugs, possibly mediating their effects through upregulation of insulin IRS-1 and Akt.

1298P Epidemiological and genomic features of patients (pts) with advanced/metastatic (a/m) non-small cell lung cancer (NSCLC) with HER2/ERBB2 mutations within and outside the tyrosine kinase domain (TKD)

1298P Epidemiological and genomic features of patients (pts) with advanced/metastatic (a/m) non-small cell lung cancer (NSCLC) with HER2/ERBB2 mutations within and outside the tyrosine kinase domain (TKD)

Long-Lasting Response to Lorlatinib in Patients with ALK-Driven Relapsed or Refractory Neuroblastoma Monitored with Circulating Tumor DNA Analysis.

We present five patients with ALK-driven relapsed or refractory neuroblastoma treated with lorlatinib as monotherapy. All patients responded to treatment, and four of them were alive after 3 to 5 years of follow-up. We performed longitudinal ctDNA analysis with ultra-deep sequencing of the ALK tyrosine kinase domain. We conclude that ctDNA analysis may guide treatment decisions in ALK-driven neuroblastoma, also when the disease is undetectable using standard clinical methods.

Heterozygous missense CSF1R variants hamper in vitro CD34+-derived dendritic cell generation but not in vivo dendritic cell development

Colony stimulating factor 1 receptor (CSF1R) is an essential receptor for both colony stimulating factor 1 (CSF1) and interleukin (IL) 34 signaling expressed on monocyte precursors and myeloid cells, including monocytes, dendritic cells (DC), and microglia. In humans, dominant heterozygous pathogenic variants in CSF1R cause a neurological condition known as CSF1R-related disorder (CSF1R-RD), typically with late onset, previously referred to as adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP). CSF1R-RD is characterized by microglia reduction and altered monocyte function; however, the impact of pathogenic CSF1R variants on the human DC lineage remains largely unknown.We previously reported that cord blood CD34+ stem cell-derived DCs generated in vitro originate specifically from CSF1R expressing precursors. In this study, we examined the DC lineage of four unrelated patients with late-onset CSF1R-RD who carried heterozygous missense CSF1R variants (c.2330G>A, c.2375C>A, c.2329C>T, and c.2381T>C) affecting different amino acids in the protein tyrosine kinase domain of CSF1R. CD34+ stem cells and CD14+ monocytes were isolated from peripheral blood and subjected to an in vitro culture protocol to differentiate towards conventional DCs and monocyte-derived DCs, respectively. Flow cytometric analysis revealed that monocytes from patients with late-onset CSF1R-RD were still able to differentiate into monocyte-derived DCs in vitro, whereas the ability of CD34+ stem cells to differentiate into conventional DCs was impaired. Strikingly, the peripheral blood of patients contained all naturally occurring DC subsets. We conclude that the in vitro abrogation of DC-development in patients with heterozygous pathogenic missense CSF1R variants does not translate to an impairment in DC development in vivo and speculate that CSF1R signalling in vivo is compensated, which needs further study.

Spontaneous Dimerization and Distinct Packing Modes of Transmembrane Domains in Receptor Tyrosine Kinases.

The insulin receptor (IR) and the insulin-like growth factor-1 receptor (IGF1R) are homodimeric transmembrane glycoproteins that transduce signals across the membrane on binding of extracellular peptide ligands. The structures of IR/IGF1R fragments in apo and liganded states have revealed that the extracellular subunits of these receptors adopt Λ-shaped configurations to which are connected the intracellular tyrosine kinase (TK) domains. The binding of peptide ligands induces structural transitions in the extracellular subunits leading to potential dimerization of transmembrane domains (TMDs) and autophosphorylation in TKs. However, the activation mechanisms of IR/IGF1R, especially the role of TMDs in coordinating signal-inducing structural transitions, remain poorly understood, in part due to the lack of structures of full-length receptors in apo or liganded states. While atomistic simulations of IR/IGF1R TMDs showed that these domains can dimerize in single component membranes, spontaneous unbiased dimerization in a plasma membrane having physiologically representative lipid composition has not been observed. We address this limitation by employing coarse-grained (CG) molecular dynamics simulations to probe the dimerization propensity of IR/IGF1R TMDs. We observed that TMDs in both receptors spontaneously dimerized independent of their initial orientations in their dissociated states, signifying their natural propensity for dimerization. In the dimeric state, IR TMDs predominantly adopted X-shaped configurations with asymmetric helical packing and significant tilt relative to the membrane normal, while IGF1R TMDs adopted symmetric V-shaped or parallel configurations with either no tilt or a small tilt relative to the membrane normal. Our results suggest that IR/IGF1R TMDs spontaneously dimerize and adopt distinct dimerized configurations.

FGFR Alterations in Thyroid Carcinoma: A Novel Class of Primary Drivers with Significant Therapeutic Implications and Secondary Molecular Events Potentially Mediating Resistance in Thyroid Malignancy.

Background: Diagnostic classification of thyroid malignancy is primarily accomplished through examination of histomorphological features and may be substantiated and clarified by molecular data. Individual molecular drivers show relatively robust and specific associations with histological subtypes of thyroid malignancy, including BRAF sequence variants and kinase gene fusions in papillary thyroid carcinoma, predominantly RAS variants in follicular-patterned neoplasia, and additional "late" mutations affecting TERT promoter, TP53, and the PI3K/AKT/PTEN pathway in high-grade malignancies. Given the oncogenic role of FGFR, particularly FGFR1-3, the goal of this study was to explore the role of FGFR in thyroid carcinoma biology. Methods: We completed a multicenter retrospective observational study for thyroid carcinomas with pathogenic alterations in the FGFR gene family. We performed this study by querying the molecular data accumulated for thyroid carcinomas from each center. Results: Overall, 5030 sequenced thyroid malignancies were reviewed, yielding 17 tumors with FGFR alterations, including 11 where FGFR was the primary molecular driver and 6 where FGFR was a secondary pathogenic alteration, with a subset for which there was available clinical follow-up data. Of the 11 carcinomas with an FGFR driver, 9 were gene fusions involving FGFR2:VCL (4 tumors), TG::FGFR1 (3 tumors), FGFR2::CIT, and FGFR2::SHTN1, and the remaining 2 were driven by FGFR1 amplification. In the 6 tumors where a canonical driver of thyroid neoplasia was present (5 cases) or no clear primary driver was detected (1 case), sequencing detected secondary FGFR2 p.W290C, p.Y375C, and p.N549K, as well as FGFR1 p.N546K in the respective tyrosine kinase domains, some at subclonal variant allele frequencies. Conclusions: This study presents the first description of a collection of thyroid carcinomas grouped by primary driver alterations in FGFR, as well as a cohort of thyroid tumors with secondary alterations that potentially lead to tumor progression or resistance to targeted therapy. Given the availability of small molecular inhibitors targeting oncogenic FGFR, this study emphasizes the significant implications for patients from identification of FGFR alterations as they are currently under-recognized in the literature and, most importantly, have potential novel treatment options.

Scaffold-hopping of Linifanib to Design 6-phenylisoxazolo[3,4-b]pyridin-3-amine Derivatives as FLT3 Inhibitors for Treating Acute Myeloid Leukemia

Background: Acute myeloid leukemia (AML) is the most common type of blood cancer. Fmslike tyrosine kinase 3 (FLT3) is a member of the class III receptor tyrosine kinase family. Overexpression of FLT3 was found in 70-100% of patients with acute myeloid leukaemia. FLT3 internal tandem duplication alteration (ITD) and the tyrosine kinase domain (TKD) are the most common molecular alteration in AML, and FLT3 has become a promising drug target for AML. Objective: A series of 6-phenylisoxazolo[3,4-b]pyridin-3-amine derivatives F1–F15 with amide bonds as FLT3 inhibitors were designed and synthesized in order to find a new lead compound to treat AML. Methods: We designed an original scaffold-hopping protocol by combing the RECAP tool with the Gilde-Based Core-Hopping tool to design novel FLT3 inhibitors based on Linifanib. Inhibitors assembled were ranked by the docking scores generated by Glide. Compounds undisclosed among the top 10 were selected to design a series of 6-phenylisoxazolo[3,4-b]pyridin-3-amine derivatives as FLT3 inhibitors. The kinase inhibitory activities of the fifteen compounds were assayed on FLT3 and FLT3-ITD. The antitumor activities of the structurally modified compounds F1–F15 were evaluated against MOLM-13 and MV4-11, typical FLT3-dependent human AML cells carrying FLT3-ITD mutants and the FLT3- independent human cervical carcinoma cell line HL-60 (harboring wide-type FLT3). Results: Structure–activity relationship (SAR) analysis showed that F14 could inhibit FLT3 and FLT3- ITD by 52% and 45.55%, respectively, at the concentration of 1 mΜ. F14 exhibited potent activity against FLT3-dependent human acute myeloid leukemia (AML) cell lines, MOLM-13, and MV4-11 (harboring FLT3-ITD mutant) with IC50 values of 2.558 μM and 1.785 μM, respectively. Conclusion: F14 could be used as a novel lead compound to further develop FLT3 inhibitors against AML with FLT3-ITD mutant.

The oncogenic fusion protein EML4-NTRK3 requires three salt bridges for stability and biological activity

Aim of studyChromosomal translocations involving neurotrophic receptor tyrosine kinases (NTRKs) have been identified in 20 % of soft tissue sarcomas. This work focuses on the EML4-NTRK3 translocation identified in cases of Infantile Fibrosarcoma, which contains the coiled-coil multimerization domain of Echinoderm Microtubule-like protein 4 (EML4) fused with the tyrosine kinase domain of Neurotrophic Receptor Tyrosine Kinase 3 (NTRK3). The aim of the study was to test the importance of tyrosine kinase activity and multimerization for the oncogenic activity of EML4-NTRK3. MethodsThese studies examined EML4-NTRK3 proteins containing a kinase-dead or WT kinase domain, together with mutations in specific salt bridge residues within the coiled-coil domain. Biological activity was assayed using focus assays in NIH3T3 cells. The MAPK/ERK, JAK/STAT3 and PI3K/AKT pathways were analyzed for downstream activation of signaling pathways. Localization of EML4-NTRK3 proteins was examined by immunofluorescence microscopy, and the ability of the EML4 coiled-coil domain to drive protein multimerization was examined by biochemical assays. ResultsActivation of EML4-NTRK3 relies on both the tyrosine kinase activity of NTRK3 and salt-bridge stabilization within the coiled-coil domain of EML4. The tyrosine kinase activity of NTRK3 is essential for the biological activation of EML4-NTRK3. Furthermore, EML4-NTRK3 activates downstream signaling pathways MAPK/ERK, JAK/STAT3 and PKC/PLCγ. The disruption of three specific salt bridge interactions within the EML4 coiled-coil domain of EML4-NTRK3 blocks downstream activation, biological activity, and the ability to hetero-multimerize with EML4. We also demonstrate that EML4-NTRK3 is localized in the cytoplasm and fails to associate with microtubules. Concluding statementThese data suggest potential therapeutic strategies for Infantile Fibrosarcoma cases bearing EML4-NTRK3 fusion through inhibition of salt bridge interactions and disruption of multimerization.

Interactive Analysis of UTX-114 Family With EGFR-tyk: Molecular Features of Acetyl Glycosylated Gefitinib.

Acetyl glucose adducts (UTX-114, -115, and -116) were prepared from gefitinib, and their characteristics (e.g., anticancer activity, structural property) were analyzed. Cytotoxicity and radiosensitizing properties of the UTX-114 family were examined using A431 cells. Supramolecular associations between the UTX-114 family compounds and the tyrosine kinase domain of epidermal growth factor receptor (EGFR-tyk) were also examined. The interactive analyses of the UTX-114 family compounds with EGFR-tyk were performed using docking simulation technique. The UTX-114 family showed a similar cytotoxicity as gefitinib, yielding IC50 values of 31.2 μM (gefitinib), 34.3 μM (UTX-114), 36.8 μM (UTX-115), and 39.4 μM (UTX-116). The EGFR-tyk inhibition ratios (IR) of UTX-114, -115, and -116 to gefitinib were 1.515, 0.983, and 0.551, respectively. The EGFR-tyk inhibitory activity of UTX-114 was higher than that of gefitinib. UTX-114 also showed the highest radiosensitizing activity among the tested compounds. UTX-114 expressed 1841 conformers (-8.989~15.718 kcal/mol) with the solvation free energy (dGW) of UTX-114 decreasing with increasing conformational energy, ranging between -354.955~ -260.815 kJ/mol. Interactive energies of gefitinib, UTX-114, -115, and -116 with EGFR-tyk were -123.640, -144.053, -120.830, and -124.658 kcal/mol, respectively. UTX-114 yielded the lowest interaction energy with EGFR-tyk among tested compounds. Given the association behavior between UTX-114 and EGFR-tyk, along with its other observed properties, UTX-114 appears to be a viable therapeutic possibility.

In-silico molecular docking, ADME study, and molecular dynamic simulation of new azetidin-2-one derivatives with antiproliferative activity

Over the past two decades, protein kinase has been a heavily studied target in the development of new anti-proliferative medications. Heterocyclic systems have been identified as the preferred scaffold because of their wide range of biological properties. In this research, the objective was to design and develop fifteen novel azetidin-2-one derivatives and assess their cytotoxic potential as inhibitors of the epidermal growth factor receptor, which is considered one of the key factors influencing cell growth and proliferation. The crystal structure of inactive EGFR tyrosine kinase domain ligand erlotinib from protein data bank was retrieved in order to be docked with our proposed azetidine-2-one derivatives to evaluate their activity as anti-proliferative agents. In this article, an in-silico molecular docking approach proposes that these azetidine-2-one derivatives have satisfactory binding contact with the erlotinib binding site. Although, three compounds have been identified as the most powerful as they have PLP fitness scores of (77.79, 76.68 and 71.46), respectively, while the reference ligand’s fitness score was (71.94). Additionally, all of our derivatives have satisfied the Swiss-ADME parameters, indicating that they may be orally active compounds. In conclusion, two compounds (A-2 and A-8) have better PLP fitness, and one (A-14) has a comparable score in comparison to the reference ligand, at the active site of epidermal growth factor receptor. indicating that the novel azetidine-2-one derivatives have shown interesting results and could be used as model compounds to create novel anti-proliferative drugs. However, more pharmacological evaluation is needed.