Abstract The epidermal growth factor receptor (EGFR) family of receptor tyrosine kinases has been implicated in a variety of cancers. In particular, activating mutations such as the L858R point mutation in exon 21 and the small in-frame deletions in exon 19 of the EGFR tyrosine kinase domain are correlated with sensitivity to EGFR tyrosine kinase inhibitors in non-small cell lung cancer (NSCLC) patients. But clinical treatment is limited by the development of drug resistance resulting mainly from an acquired mutation (T790M). In this study, we evaluated the therapeutic potential of a novel, irreversible pan-HER inhibitor, HM781–36B. We demonstrated that HM781–36B is a potent EGFR inhibitor including the EGFR-acquired resistance mutation (IC50 4.2 nM in EGFR T790M and IC50 2.2 nM in EGFR L858R/T790M), as well as EGFR, HER-2 and HER-4 (IC50 3.2 nM, 5.3 nM and 23.5 nM, respectively), compared to other EGFR tyrosine kinases inhibitors (erlotinib, lapatinib and BIBW-2992), with kinase selectivity confirmed by 77 kinases panel assay except for Blk, Bmx and Btk. Strong growth inhibitory activity by the treatment of HM781–36B was confirmed with the range of IC50 0.6–6nM in NSCLC (HCC827, H358, H1975, Calu-3, and H1781), breast cancer (SK-Br3, BT474, MDA-175, and MDA-453), and gastric cancer (N87 and SNU-216) cell lines. HM781–36B showed 400–4,000 fold low growth inhibitory effect against normal cell lines (Hs-27 and Balb/c 3T3) relative to cancer cell lines. HM781–36B treatment results in the inhibition of EGFR phosphorylation and the subsequent deactivation of downstream signaling proteins in EGFR DelE746_A750-harboring erlotinib-sensitive HCC827 and EGFR L858R/T790M-harboring erlotinib-resistant NCI-H1975 NSCLC cells. HM781–36B interacts directly with its target enzyme (EGFR WT, EGFR T790M, HER-2), which was confirmed through prolongation study of phosphorylation inhibitory effect in A431 and SK-Br3 cells and direct fluorescence-based SDS-PAGE analysis by the incubation of Cy3-labeled HM781–36B probe. This irreversible occupation at the kinase domain leads to excellent in vivo efficacy of HM781–36B (1mg/kg – 5mg/kg) toward various xenograft models with EGFR-dependent cancers cells, including erlotinib-sensitive HCC827 NSCLC cells, erlotinib-resistant H1975 NSCLC cells, HER-2 overexpressing Calu-3 NSCLC cells, N87 gastric cancer cells, and SK-Ov3 ovarian cancer cells, and EGFR-overexpressing A431 epidermoid carcinoma cancer cells. On the basis of these preclinical results, HM781–36B was selected as a candidate for clinical development and a phase I study of HM781–36B is currently undergoing in South Korea. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-389. doi:10.1158/1538-7445.AM2011-LB-389
Abstract Small‐molecule glucose uptake enhancers targeted to myotubes and adipocytes were developed through a phenotypic screening linked with target identification and rational optimization. The target protein of glucose‐uptake enhancers was identified as a nuclear receptor PPARγ (peroxisome proliferator‐activated receptor gamma). Subsequent optimization of initial hits generated lead compounds with high potency for PPARγ transactivation and cellular glucose uptake. Finally, we confirmed that the chirality of optimized ligands differentiates their PPARγ transcriptional activity, binding affinity, and inhibitory activity toward Cdk5 (cyclin‐dependent kinase 5)‐mediated phosphorylation of PPARγ at Ser273. Using phenotype‐based lead discovery along with early‐stage target identification, this study has identified a new small‐molecule enhancer of glucose uptake that targets PPARγ.
A novel series of N4-(3-chlorophenyl)-5-(oxazol-2-yl)pyrimidine-4,6-diamines were synthesized and evaluated as dual inhibitors of HER-1/HER-2 tyrosine kinases. In contrast to the currently approved HER-2-targeted agent (lapatinib, 1), our irreversible HER-1/HER-2 inhibitors have the potential to overcome the clinically relevant and mutation-induced drug resistance. The selected compound (19a) showed excellent inhibitory activity toward HER-1/HER-2 tyrosine kinases with selectivity over 20 other kinases and inhibited the proliferation of both cancer cell types: lapatinib-sensitive cell lines (SK-Br3, MDA-MB-175, and N87) and lapatinib-resistant cell lines (MDA-MB-453, H1781, and H1975). The excellent pharmacokinetic profiles of 19a in mice and rats led us to further investigation of a novel therapeutic agent for HER-2-targeting treatment of solid tumors, especially HER-2-positive breast/gastric cancer and HER-2-mutated lung cancer.
We developed fluorescent biosensor systems that are either general or selective to fluoroquinolone antibiotics by using a single-chain variable-fragment (scFv) as a recognition element. The selectivity of these biosensors to fluoroquinolone antibiotics was rationally tuned through the structural modification on the pharmacophore of fluoroquinolone antibiotics and the subsequent selection of scFv receptor modules against these antibiotics-based antigens using phage display. The resulting A2 and F9 scFv's bound to their representative antigen with a moderate affinity (K(D) in micromolar range as determined by surface plasmon resonance). A2 is a specific binder for enrofloxacin and did not cross-react with other fluoroquinolone antibiotics including structurally similar ciprofloxacin, while F9 is a general fluoroquinolone binder that likely bound to the antigen at the common pyridone-carboxylic acid pharmacophore. These scFv-based receptors were successfully applied to the development of one-step fluorescent biosensor which can detect fluoroquinolone antibiotics at concentrations below the level suggested in animal drug application guidelines. The strategy described in this report can be applied to developing convenient field biosensors that can qualitatively detect overused/misused antibiotics in the livestock drinking water.
The phenotype-based discovery of novel therapeutic agents has suffered from the lengthy process of target deconvolution. In their Communication on page 5102 ff., S. B. Park et al. show that the convergent strategy of phenotype screening with early stage target identification can bridge the gap between phenotype-based hit discovery and rational drug discovery to generate a new class of therapeutic agents. They were able to identify a new small-molecule enhancer of cellular glucose uptake that targets PPARγ.
A novel series of (S)-1-acryloyl-N-[4-(arylamino)-7-(alkoxy)quinazolin-6-yl]pyrrolidine-2-carboxamides were synthesized and evaluated as Her-1/Her-2 dual inhibitors. In contrast to the Her-1 selective inhibitors, our novel compounds are irreversible inhibitors of Her-1 and Her-2 tyrosine kinases with the potential to overcome clinically relevant, mutation-induced drug resistance. The selected compounds (19c, 19d) showed excellent EGFR inhibition activity even toward the T790M mutation of Her-1 tyrosine kinase with excellent selectivity. The excellent pharmacokinetic profiles of these compounds in rats and their robust in vivo efficacy in an A431 xenograft model clearly demonstrate that they merit further investigation as novel therapeutic agents for EGFR-targeting treatment of solid tumors, especially Her-1 selective inhibitor-resistant non-small cell lung cancer.
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