Nuclear translocation of epidermal growth factor receptor by Akt-dependent phosphorylation enhances breast cancer-resistant protein expression in gefitinib-resistant cells.
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Huang WC, Chen YJ, Li LY, Wei YL, Hsu SC, Tsai SL, Chiu PC, Huang WP, Wang YN, Chen CH, Chang WC, Chang WC, Chen AJ, Tsai CH, Hung MC
Nuclear translocation of epidermal growth factor receptor by Akt-dependent phosphorylation enhances breast cancer-resistant protein expression in gefitinib-resistant cells.
J Biol Chem. 2011 Jun 10;286(23):20558-68. doi: 10.1074/jbc.M111.240796. Epub 2011 Apr 12.
- PubMed ID
- 21487020 [ View in PubMed]
- Abstract
Epidermal growth factor receptor (EGFR), an aberrantly overexpressed or activated receptor-tyrosine kinase in many cancers, plays a pivotal role in cancer progression and has been an attractive target for cancer therapy. Gefitinib and erlotinib, two EGFR-tyrosine kinase inhibitors, have been approved for non-small cell lung cancer. However, durable clinical efficacy of these EGFR inhibitors is severely limited by the emergence of acquired resistance. For example, the expression of breast cancer-resistant protein (BCRP/ABCG2) has been shown to confer acquired resistance of wild-type EGFR (wtEGFR)-expressing cancer cells to gefitinib. However, the underlying molecular mechanisms still remain unclear. Here, we show that wtEGFR expression is elevated in the nucleus of acquired gefitinib-resistant cancer cells. Moreover, nuclear translocation of EGFR requires phosphorylation at Ser-229 by Akt. In the nucleus, EGFR then targets the proximal promoter of BCRP/ABCG2 and thereby enhances its gene transcription. The nuclear EGFR-mediated BCRP/ABCG2 expression may contribute at least in part to the acquired resistance of wtEGFR-expressing cancer cells to gefitinib. Our findings shed light on the role of nuclear EGFR in the sensitivity of wtEGFR-expressing cancer cells to EGFR tyrosine kinase inhibitors and also deciphered a putative molecular mechanism contributing to gefitinib resistance through BCRP/ABCG2 expression.