Notch-1 regulates transcription of the epidermal growth factor receptor through p53.
The Notch pathway plays a key role in the development and is increasingly recognized for its importance in cancer. We demonstrated previously the overexpression of Notch-1 and its ligands in gliomas and showed that their knockdown inhibits glioma cell proliferation and survival. To elucidate the mechanisms downstream of Notch-1 in glioma cells, we performed microarray profiling of glioma cells transfected with Notch-1 small interfering RNA. Notable among downregulated transcripts was the epidermal growth factor receptor (EGFR), known to be overexpressed or amplified in gliomas and prominent in other cancers as well. Further studies confirmed that Notch-1 inhibition decreased EGFR messenger RNA (mRNA) and EGFR protein in glioma and other cell lines. Transfection with Notch-1 increased EGFR expression. Additionally, we found a significant correlation in levels of EGFR and Notch-1 mRNA in primary high-grade human gliomas. Subsequent experiments showed that p53, an activator of the EGFR promoter, is regulated by Notch-1. Experiments with p53-positive and -null cell lines confirmed that p53 partially mediates the effects of Notch-1 on EGFR expression. These results show for the first time that Notch-1 upregulates EGFR expression and also demonstrate Notch-1 regulation of p53 in gliomas. These observations have significant implications for understanding the mechanisms of Notch in cancer and development.
Purow
Benjamin W
BW
Department of Neurology, Division of Neuro-Oncology, University of Virginia, Charlottesville, VA 22908, USA. bwp5g@virginia.edu
Sundaresan
Tilak K
TK
Burdick
Michael J
MJ
Kefas
Benjamin A
BA
Comeau
Laurey D
LD
Hawkinson
Michael P
MP
Su
Qin
Q
Kotliarov
Yuri
Y
Lee
Jeongwu
J
Zhang
Wei
W
Fine
Howard A
HA
D001706:Biopsy; D001932:Brain Neoplasms / Q000235:genetics / Q000473:pathology; D066246:ErbB Receptors / Q000235:genetics*; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D016158:Genes, p53; D005910:Glioma / Q000235:genetics* / Q000473:pathology; D006801:Humans; D008156:Luciferases / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D051881:Receptor, Notch1 / Q000235:genetics / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic; D014162:Transfection; D016159:Tumor Suppressor Protein p53 / Q000235:genetics*
C497761:NOTCH1 protein, human; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D051881:Receptor, Notch1; D016159:Tumor Suppressor Protein p53; D008156:Luciferases; D066246:ErbB Receptors