Abstract 40: HB-EGF‑mediated CITED4 signaling in lung cancer

Abstract

Abstract Abnormal activation of the EGF receptor (EGFR) signaling is a hallmark of lung cancer. However, the role of heparin-binding EGF-like growth factor (HB-EGF), one of EGFR ligands, in lung tumorigenesis has been unappreciated. In this study, we showed that HB-EGF was highly expressed in a subgroup of lung cancer cells, the proliferation of which was dependent on HB-EGF signaling. Members of CITED family proteins respond to various cytokine signalings, regulating cell proliferation; among them, we identified CITED4 as a downstream effecter of HB-EGF. We revealed that CITED4 was upregulated by HB-EGF through a STAT3 dependent pathway. Moreover, CITED4-silencing attenuated HB-EGF-mediated lung cancer cell proliferation. ChIP analysis and promoter reporter assay showed that STAT3 bound CITED4 promoter, enhancing CITED4 transcription. Co-immunoprecipitation analysis identified MYC as a CITED4-interacting protein. Furthermore, we found that CITED4 expression promoted MYC-mediated transcription of cyclin D1 promoter, leading to increased G1/S cell cycle transition. Thus, our findings support that HB-EGF-CITED4 signaling cascade plays a critical role in aberrant proliferation in lung cancer with potential as a biomarker for lung cancer progression. Citation Format: Cheng-Han Hsieh, Yu-Ting Chou, Cheng-Wen Wu. HB-EGF‑mediated CITED4 signaling in lung cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 40. doi:10.1158/1538-7445.AM2015-40