41 research outputs found
Synergistic inactivation of AXL: a (cross)road to cure ovarian cancer?
No full textInternational audienceComment on: The tumour suppressor OPCML promotes AXL inactivation by the phosphatase PTPRG in ovarian cancer. [EMBO Rep. 2018]Inhibition of the receptor tyrosine kinase AXL, a key molecular driver of ovarian cancer, has recently been highlighted as promising therapeutic strategy. In this issue of EMBO Reports, Antony et al 1 have identified a novel mechanism of inhibition of AXL, wherein the GPI‐anchored tumour suppressor OPCML sequesters AXL into specialised plasma membrane domains where the phosphatase PTPRG is located, therefore facilitating AXL dephosphorylation. This [...
The SNP rs6508974 in AXL is a functional polymorphism and a promising biomarker for gefitinib treatment
No full textNagasaki University (長崎大学)博士(医学)Somatic mutations in epidermal growth factor receptor (EGFR) found in lung adenocarcinomas are used as biomarkers for the treatment with EGFR-tyrosine kinase inhibitors, including gefitinib. The bypass tracks with amplification of AXL is one of the mechanisms underlying the resistance to gefitinib. We, therefore, carried out a candidate gene approach method to identify AXL polymorphisms associated with the effectiveness of gefitinib. EGFR mutations were first identified by mutantenriched PCR-restriction fragment length polymorphism (RFLP), and then 2 tag single nucleotide polymorphisms (SNPs) of AXL were examined by PCR-RFLP in 62 Japanese patients with advanced lung adenocarcinoma and treated with gefitinib in two general hospitals in Nagasaki. Subsequently, the association of EFGR mutations and the AXL polymorphism with the effectiveness of gefitinib was examined in these patients. We next examined the effect of the AXL polymorphism on the
expression and function of this gene. It is worthy of note that EGFR mutations and the AXL polymorphism rs6508974 independently contributed to the effectiveness of gefitinib, and the polymorphism was proved to be a possible biomarker for selecting non-responders and responders to gefitinib treatment even in the absence of EGFR mutations. Furthermore, this SNP increased the transcriptional activity of the AXL transcript variant 3, one of the three AXL transcript variants, which to some extent increased the epithelial-mesenchymal transition in cancer cells. Taken together, AXL is one of the genes that determine the effectiveness of gefitinib and a biomarker for selecting non-responders and responders among lung adenocarcinoma patients with no EGFR mutations, suggesting that rs6508974 in AXL might be a functional SNP in lung adenocarcinoma.長崎大学学位論文 学位記番号:博(医歯薬)甲第1415号 学位授与年月日:令和4年3月2日Author: Megumi Kamikatahira, Tatsuo Inamine, Sara Kawano, Haruna Ohba, Kyohei Obata, Risako Iwanaga, Minoru Fukuda, Masaaki Fukuda, Hiroyuki Yamaguchi, Tatsuro Hirayama, Hiroshi Mukae, and Kazuhiro TsukamotoCitation: ACTA MEDICA NAGASAKIENSIA, 65(3), pp.111−121; 2022Nagasaki University (長崎大学), 博士(医学) (2022-03-02)doctoral thesi
Gas6 derived from cancer-associated fibroblasts promotes migration of Axl-expressing lung cancer cells during chemotherapy
No full textAlterations to the tumor stromal microenvironment induced by chemotherapy could influence the behavior of cancer cells. In the tumor stromal microenvironment, cancer-associated fibroblasts (CAFs) play an important role. Because the receptor tyrosine kinase Axl and its ligand Gas6 could be involved in promoting non-small cell lung cancer (NSCLC), we investigated the role of Gas6 secreted by CAFs during chemotherapy in NSCLC. In a murine model, we found that Gas6 expression by CAFs was upregulated following cisplatin treatment. Gas6 expression might be influenced by intratumoral hypoperfusion during chemotherapy, and it increased after serum starvation in a human lung CAF line, LCAFhTERT. Gas6 is associated with LCAFhTERT cell growth. Recombinant Gas6 promoted H1299 migration, and conditioned medium (CM) from LCAFhTERT cells activated Axl in H1299 cells and promoted migration. Silencing Gas6 in LCAFhTERT reduced the Axl activation and H1299 cell migration induced by CM from LCAFhTERT. In clinical samples, stromal Gas6 expression increased after chemotherapy. Five-year disease-free survival rates for patients with tumor Axl- and stromal Gas6-positive tumors (n = 37) was significantly worse than for the double negative group (n = 12) (21.9% vs 51.3%, p = 0.04). Based on these findings, it is presumed that Gas6 derived from CAFs promotes migration of Axl-expressing lung cancer cells during chemotherapy and is involved in poor clinical outcome. © 2017 The Author(s).金沢大学医薬保健研究域医学系journal articl
Paratope mapping of tilvestamab, an anti-AXL function-blocking antibody, using high-throughput bacterial expression of secreted scFv-ompY fusion proteins
No full textAbstract
Targeting AXL with a highly selective antibody presents a promising approach for inhibiting AXL and potentially improving cancer treatment. An essential step in antibody optimisation is the mapping of paratope residues to epitope residues. In this study, we identify the residues of tilvestamab, a function-blocking anti-AXL monoclonal antibody (mAb), that are essential for its binding to the extracellular domain of AXL. A single-chain variable fragment (scFv) fused to osmotically inducible protein Y (osmY) was designed to enable the secretion of soluble scFv-osmY mutants, which could be directly subjected to high-throughput biolayer interferometry (BLI) screening for binding to the AXL Ig1 domain. Each CDR residue of scFv was mutated to Ala, while additional mutations were made on the basis of predicted contribution to binding. We generated AlphaFold3 predictions for the scFv(tilvestamab)-AXL Ig1 complex to gain insights into the molecular interactions of the essential residues, as determined by the experimental data. Our study reveals that tilvestamab binds to the Ig1 domain of AXL, with twelve residues on scFv (tilvestamab) contributing most to binding, likely being situated at the binding interface. Glu2 near the N terminus of AXL is essential for binding. The data give a structural view into the AXL-tilvestamab complex and allow for further optimisation of the binding interface.Abstract
Targeting AXL with a highly selective antibody presents a promising approach for inhibiting AXL and potentially improving cancer treatment. An essential step in antibody optimisation is the mapping of paratope residues to epitope residues. In this study, we identify the residues of tilvestamab, a function-blocking anti-AXL monoclonal antibody (mAb), that are essential for its binding to the extracellular domain of AXL. A single-chain variable fragment (scFv) fused to osmotically inducible protein Y (osmY) was designed to enable the secretion of soluble scFv-osmY mutants, which could be directly subjected to high-throughput biolayer interferometry (BLI) screening for binding to the AXL Ig1 domain. Each CDR residue of scFv was mutated to Ala, while additional mutations were made on the basis of predicted contribution to binding. We generated AlphaFold3 predictions for the scFv(tilvestamab)-AXL Ig1 complex to gain insights into the molecular interactions of the essential residues, as determined by the experimental data. Our study reveals that tilvestamab binds to the Ig1 domain of AXL, with twelve residues on scFv (tilvestamab) contributing most to binding, likely being situated at the binding interface. Glu2 near the N terminus of AXL is essential for binding. The data give a structural view into the AXL-tilvestamab complex and allow for further optimisation of the binding interface
Overcoming PLK1 inhibitor resistance by targeting mevalonate pathway to impair AXL-TWIST axis in colorectal cancer
No full text© 2021 The Author(s).New therapeutic targets are revolutionizing colorectal cancer clinical management, opening new horizons in metastatic patients’ outcome. Polo Like Kinase1 (PLK1) inhibitors have high potential as antitumoral agents, however, the emergence of drug resistance is a major challenge for their use in clinical practice. Overcoming this challenge represents a hot topic in current drug discovery research. BI2536-resistant colorectal cancer cell lines HT29R, RKOR, SW837R and HCT116R, were generated in vitro and validated by IG50 assays and xenografts models by the T/C ratio. Exons 1 and 2 of PLK1 gene were sequenced by Sanger method. AXL pathway, Epithelial-to-Mesenchymal transition (EMT) and Multidrug Resistance (MDR1) were studied by qPCR and western blot in resistant cells. Simvastatin as a re-sensitizer drug was tested in vitro and the drug combination strategies were validated in vitro and in vivo. PLK1 gene mutation R136G was found for RKOR. AXL pathway trough TWIST1 transcription factor was identified as one of the mechanisms involved in HT29R, SW837R and HCT116R lines, inducing EMT and upregulation of MDR1. Simvastatin was able to impair the mechanisms activated by adaptive resistance and its combination with BI2536 re-sensitized resistant cells in vitro and in vivo. Targeting the mevalonate pathway contributes to re-sensitizing BI2536-resistant cells in vitro and in vivo, raising as a new strategy for the clinical management of PLK1 inhibitors.This study has been funded by Instituto de Salud Carlos III (ISCIII) -Fondos FEDER proyects PI16/01468 and PI19/01231
Phase I Study Evaluating Glesatinib (MGCD265), An Inhibitor of MET and AXL, in Patients with Non-small Cell Lung Cancer and Other Advanced Solid Tumors
No full textBackground: Heightened signaling by mesenchymal epithelial transition factor (MET) is implicated in tumorigenesis. Glesatinib is an investigational, oral inhibitor of MET and AXL.
Objective: This phase I study determined the maximum tolerated dose (MTD), recommended phase II dose (RP2D), and safety profile of glesatinib in patients with advanced or unresectable solid tumors. Antitumor activity and pharmacokinetics (PK) were secondary objectives.
Patients and methods: Four formulations of glesatinib glycolate salt (capsule, unmicronized, micronized, and micronized version 2 [V2] tablets) and two free-base formulations (free-base suspension [FBS] capsule and spray-dried dispersion [SDD] tablet), developed to enhance drug exposure and optimize manufacturing processes, were evaluated in patients with genetically unselected advanced/unresectable solid tumors. MTD, based on dose-limiting toxicities (DLTs) observed during the first 21-day treatment cycle, was further evaluated in dose-expansion cohorts comprising patients with overexpression of MET and/or AXL, MET/AXL amplification, MET-activating mutations, or MET/AXL rearrangements for confirmation as the RP2D.
Results: Glesatinib was evaluated across 27 dose-escalation cohorts (n = 108). Due to suboptimal exposure with glesatinib glycolate salt formulations in the initial cohorts, investigations subsequently focused on the FBS capsule and SDD tablet; for these formulations, MTD was identified as 1050 mg twice daily and 750 mg twice daily, respectively. An additional 71 patients received glesatinib in the FBS and SDD dose-expansion cohorts. At MTDs, the most frequent treatment-related adverse events were diarrhea (FBS, 83.3%; SDD, 75.0%), nausea (57.1%, 30.6%), vomiting (45.2%, 25.0%), increased alanine aminotransferase (45.2%, 30.6%), and increased aspartate aminotransferase (47.6%, 27.8%). Exploratory pharmacodynamic analyses indicated target engagement and inhibition of MET by glesatinib. Antitumor activity was observed with glesatinib FBS 1050 mg twice daily and SDD 750 mg twice daily in tumors harboring MET/AXL alteration or aberrant protein expression, particularly in patients with non--small cell lung cancer (NSCLC). In patients with NSCLC, the objective response rate was 25.9% in those with MET/AXL mutation or amplification and 30.0% in a subset with MET-activating mutations. All six partial responses occurred in patients with tumors carrying MET exon 14 deletion mutations.
Conclusions: The safety profile of single-agent glesatinib was acceptable. SDD 750 mg twice daily was selected as the preferred glesatinib formulation and dose based on clinical activity, safety, and PK data. Observations from this study led to initiation of a phase II study of glesatinib in patients with NSCLC stratified by type of MET alteration (NCT02544633).
Clinical trials registration: ClinicalTrials.gov NCT00697632; June 2008.
© 2022. The Author(s), under exclusive licence to Springer Nature Switzerland AG.restrictio
ANTIDIABETIC ACTIVITY TEST OF BITTER GOURD EXTRACT (Momordica charantia) AS AN INHIBITOR OF α - GLUCOSIDASE ENZYME BY IN SILICO
No full textABSTRACTDiabetes mellitus (DM) is a metabolic disorder that interferes with the metabolism of carbohydrates, fats, and proteins. This study aims to determine the types of bioactive compounds contained in bitter melon extract and to analyze interaction of targeted compounds against the α -glucosidase enzyme using the in silico approach. The results of the analysis using Gas Chromatography- Mass Spectrometer (GCMS) used to obtain information on bioactive compounds that will be used as ligands to be attached to the α-glucosidase enzyme. Furthermore, the potential ability of each compound as antidiabetic was test using PyRx application and Acarbose was its control. The results of the GCMS analysis of this study contained 23 compounds detected in the methanol extract of bitter melon. This research proves that the compound Spirost-8-en-11 one, 3 hydroxy, (3ß,5a,14ß, 20ß, 22ß, 25R) with a binding affinity of -9.0 kcal/mol and Cholesta-8,24-dien -3-ol, 4-methyl-, (3ß,4a)- with a binding affinity of -8.3 kcal/mol have a good conformation. This research can be concluded that the two compounds can be developed as antidiabetic.  Keywords: Bitter Melon (Momordica charantia), antidiabetic, α - Glucosidase enzyme, molecular dockin
PERKEMBANGAN DAN DASAR BIOLOGIS VIRUS WEST NILE
No full textABSTRACTWest Nile virus is a neurotropic pathogen that can cause West Nile fever or encephalitis. The expansion of west nile virus is strongly influenced by mosquitoes, especially with the type of culex sp and aedes sp. The virus has a single-stranded RNA genome that is believed to have very rapid adaptation and spread. Mutations in west nile virus can occur in both structural proteins and non-structural proteins. In previous studies, it was explained that mutations in the structural protein west nile virus are beneficial because they can reduce mortility by up to 50% in invivo test. However, antiviral drugs and vaccines in humans specific to west nile virus are still being temporarily developed. This review discusses more about the development, biological basis and diagnosis of therapy and prevention of the spread of west nile virus.Keywords: West nile virus, Evolution, Biological Basis, Diagnosis, Treatment and Pevention ABSTRAKVirus West Nile merupakan patogen yang bersifat neurotropik yang dapat menyebabkan demam west nile maupun ensefalitis. Perluasan dari virus west nile ini sangat dipengaruhi oleh nyamuk terutama dengan jenis culex sp dan aedes sp. Virus ini memiliki genom single-stranded RNA yang dipercaya memiliki adaptasi dan penyebaran yang sangat cepat. Mutasi pada virus west nile dapat terjadi baik pada protein struktural maupun protein non-struktural. Pada penelitian sebelumnya dijelaskan bahwa mutasi pada protein structural virus west nile bersifat menguntungkan dikarenakan mampu menurunkan mortilitas hingga 50% pada hewan uji. Namun, Obat antiviral dan vaksin pada manusia yang spesifik terhadap virus west nile ini masih sementara dikembangkan. Ulasan ini membahas lebih lanjut mengenai perkembangan, dasar biologis serta diagnosis terapi dan pencegahan dari penyebaran virus west nile.Kata kunci: Virus west nile, Perkembangan, Dasar Biologis, Diagnosis, Pengobatan dan Pencegaha
In vivo turnover and biodistribution of soluble AXL: implications for biomarker development
No full textAbstract
Soluble biomarkers are paramount to personalized medicine. However, the in vivo turnover and biodistribution of soluble proteins is seldom characterized. The cleaved extracellular domain of the AXL receptor (sAXL) is a prognostic biomarker in several diseases and a predictive marker of AXL targeting agents. Plasma sAXL reflects a balance between production in tissues with lymphatic transport into the circulation and removal from blood by degradation or excretion. It is unclear how this transport cycle affects plasma sAXL levels that are the metric for biomarker development. Radiolabeled mouse sAxl was monitored after intravenous injection to measure degradation and urinary excretion of sAxl, and after intradermal injection to mimic tissue or tumor production. sAxl was rapidly taken-up and degraded by the liver and kidney cortex. Surprisingly, intact sAxl was detectable in urine, indicating passage through the glomerular filter and a unique sampling opportunity. The structure of sAxl showed an elongated, flexible molecule with a length of 18 nm and a thickness of only 3 nm, allowing passage through the glomerulus and excretion into the urine. Intradermally injected sAxl passed through local and distant lymph nodes, followed by uptake in liver and kidney cortex. Low levels of sAxl were seen in the plasma, consistent with an extended transit time from local tissue to circulation. The rapid plasma clearance of sAxl suggests that steady-state levels in blood will sensitively and dynamically reflect the rate of production of sAxl in the tissues but will be influenced by perturbations of liver and kidney function.Abstract
Soluble biomarkers are paramount to personalized medicine. However, the in vivo turnover and biodistribution of soluble proteins is seldom characterized. The cleaved extracellular domain of the AXL receptor (sAXL) is a prognostic biomarker in several diseases and a predictive marker of AXL targeting agents. Plasma sAXL reflects a balance between production in tissues with lymphatic transport into the circulation and removal from blood by degradation or excretion. It is unclear how this transport cycle affects plasma sAXL levels that are the metric for biomarker development. Radiolabeled mouse sAxl was monitored after intravenous injection to measure degradation and urinary excretion of sAxl, and after intradermal injection to mimic tissue or tumor production. sAxl was rapidly taken-up and degraded by the liver and kidney cortex. Surprisingly, intact sAxl was detectable in urine, indicating passage through the glomerular filter and a unique sampling opportunity. The structure of sAxl showed an elongated, flexible molecule with a length of 18 nm and a thickness of only 3 nm, allowing passage through the glomerulus and excretion into the urine. Intradermally injected sAxl passed through local and distant lymph nodes, followed by uptake in liver and kidney cortex. Low levels of sAxl were seen in the plasma, consistent with an extended transit time from local tissue to circulation. The rapid plasma clearance of sAxl suggests that steady-state levels in blood will sensitively and dynamically reflect the rate of production of sAxl in the tissues but will be influenced by perturbations of liver and kidney function
