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Am J Respir Crit Care Med. 2016 Apr 1;193(7):753-66. doi: 10.1164/rccm.201502-0250OC.

Small Molecule T315 Promotes Casitas B-Lineage Lymphoma-Dependent Degradation of Epidermal Growth Factor Receptor via Y1045 Autophosphorylation.

Author information

1
1 Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan.
2
2 Research Center for Tumor Medical Science, China Medical University, Taichung, Taiwan.
3
3 Institute of Biomedical Sciences.
4
4 Research Center for Industry of Human Ecology.
5
5 Graduate Institute of Health Industry Technology, Chang Gung University of Science and Technology, Kwei-San, Tao-Yuan, Taiwan.
6
6 Department of Medical Research, Taichung Veterans General Hospital, Taichung, Taiwan.
7
7 Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, and.
8
8 Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan.
9
9 Department of Clinical and Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Taipei, Taiwan.
10
10 NTU Center of Genomic Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan.
11
11 Institute of Clinical Medicine, National Cheng Kung University College of Medicine, Tainan, Taiwan; and.
12
12 Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan.
13
13 Division of Medicinal Chemistry, College of Pharmacy and Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio.
14
14 Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan.

Abstract

RATIONALE:

Despite the fact that tyrosine kinase inhibitors (TKIs) have been found effective in treating patients harboring activating mutations of epidermal growth factor receptor (EGFR), an acquired secondary mutation, T790M, which lowers the affinity to TKIs, can lead to EGFR TKI resistance after this standard treatment.

OBJECTIVES:

To evaluate the effect of small molecule T315 on EGFR degradation and its therapeutic efficacy in vitro and in vivo.

METHODS:

Lung adenocarcinoma cells were treated with T315, and cell proliferation and apoptotic proportion were determined by the CellTiter 96 AQueous MTS (3-[4,5-dimethylthiazol-2-yl]-5-[3-carboxymethoxyphenyl]-2-[4-sulfophenyl]-2H-tetrazolium, inner salt) assay and flow cytometry. The effects of T315 on EGFR mRNA and protein levels, autophosphorylation, ubiquitination, and degradation were evaluated by real-time polymerase chain reaction and Western blot, respectively. Direct targeting of T315 to EGFR was confirmed by the in vitro kinase assay and mass spectrometry. Finally, the preclinical effect of T315 was validated in the murine xenograft model in combination with a second-generation TKI, afatinib.

MEASUREMENTS AND MAIN RESULTS:

We identified T315 as a novel, potent small molecule for suppressing cancer cell proliferation in vitro and in vivo. The therapeutic effect was verified after T315 was combined with a second-generation TKI, afatinib, compared with a single drug administration. We found a new mechanism of action, in that T315 appears to directly bind EGFR and triggers EGFR-Y1045 autophosphorylation, whereby its degradation is triggered through the ubiquitin-proteasome pathway.

CONCLUSIONS:

Our evidence suggests that T315 is a novel class of anticancer drug that is able to inhibit the growth of EGFR-TKI-resistant lung adenocarcinoma cells by inducing the degradation of EGFR.

KEYWORDS:

T315; casitas B-lineage lymphoma; epidermal growth factor receptor degradation; lung adenocarcinoma

PMID:
26583948
DOI:
10.1164/rccm.201502-0250OC
[Indexed for MEDLINE]

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