5 research outputs found
Quantitation of endogenous metabolites in mouse tumors using mass-spectrometry imaging
Described is a quantitative-mass-spectrometryimaging
(qMSI) methodology for the analysis of lactate and
glutamate distributions in order to delineate heterogeneity
among mouse tumor models used to support drug-discovery
efficacy testing. We evaluate and report on preanalysisstabilization
methods aimed at improving the reproducibility
and efficiency of quantitative assessments of endogenous
molecules in tissues. Stability experiments demonstrate that
optimum stabilization protocols consist of frozen-tissue
embedding, post-tissue-sectioning desiccation, and storage at
−80 °C of tissue sections sealed in vacuum-tight containers.
Optimized stabilization protocols are used in combination with qMSI methodology for the absolute quantitation of lactate and
glutamate in tumors, incorporating the use of two different stable-isotope-labeled versions of each analyte and spectral-clustering
performed on each tissue section using k-means clustering to allow region-specific, pixel-by-pixel quantitation. Region-specific
qMSI was used to screen different tumor models and identify a phenotype that has low lactate heterogeneity, which will enable
accurate measurements of lactate modulation in future drug-discovery studies. We conclude that using optimized qMSI
protocols, it is possible to quantify endogenous metabolites within tumors, and region-specific quantitation can provide valuable
insight into tissue heterogeneity and the tumor microenvironment
AZD9291, an irreversible EGFR TKI, overcomes T790M-mediated resistance to EGFR inhibitors in lung cancer
First-generation EGFR tyrosine kinase inhibitors (EGFR TKI) provide significant clinical benefit in patients with advanced EGFR-mutant (EGFRm(+)) non-small cell lung cancer (NSCLC). Patients ultimately develop disease progression, often driven by acquisition of a second T790M EGFR TKI resistance mutation. AZD9291 is a novel oral, potent, and selective third-generation irreversible inhibitor of both EGFRm(+) sensitizing and T790M resistance mutants that spares wild-type EGFR. This mono-anilino-pyrimidine compound is structurally distinct from other third-generation EGFR TKIs and offers a pharmacologically differentiated profile from earlier generation EGFR TKIs. Preclinically, the drug potently inhibits signaling pathways and cellular growth in both EGFRm(+) and EGFRm(+)/T790M(+) mutant cell lines in vitro, with lower activity against wild-type EGFR lines, translating into profound and sustained tumor regression in EGFR-mutant tumor xenograft and transgenic models. The treatment of 2 patients with advanced EGFRm(+) T790M(+) NSCLC is described as proof of principle. SIGNIFICANCE: We report the development of a novel structurally distinct third-generation EGFR TKI, AZD9291, that irreversibly and selectively targets both sensitizing and resistant T790M(+) mutant EGFR while harboring less activity toward wild-type EGFR. AZD9291 is showing promising responses in a phase I trial even at the first-dose level, with first published clinical proof-of-principle validation being presented. (C) 2014 AACR.
Discovery of a potent and selective EGFR inhibitor (AZD9291) of both sensitizing and T790M resistance mutations that spares the wild type form of the receptor
Discovery of a Potent and Selective EGFR Inhibitor (AZD9291) of Both Sensitizing and T790M Resistance Mutations That Spares the Wild Type Form of the Receptor
Epidermal growth factor receptor
(EGFR) inhibitors have been used clinically in the treatment of non-small-cell
lung cancer (NSCLC) patients harboring sensitizing (or activating)
mutations for a number of years. Despite encouraging clinical efficacy
with these agents, in many patients resistance develops leading to
disease progression. In most cases, this resistance is in the form
of the T790M mutation. In addition, EGFR wild type receptor inhibition
inherent with these agents can lead to dose limiting toxicities of
rash and diarrhea. We describe herein the evolution of an early, mutant
selective lead to the clinical candidate AZD9291, an irreversible
inhibitor of both EGFR sensitizing (EGFRm+) and T790M resistance mutations
with selectivity over the wild type form of the receptor. Following
observations of significant tumor inhibition in preclinical models,
the clinical candidate was administered clinically to patients with
T790M positive EGFR-TKI resistant NSCLC and early efficacy has been
observed, accompanied by an encouraging safety profile