Egr1 Transcription Factor: Multiple Roles in Prostate Tumor Cell Growth and SurvivalAdamson E.D. · Mercola D.
aBurnham Institute, La Jolla, Calif., and bSidney Kimmel Cancer Center, San Diego, Calif., USA
The transcription factor, Egr1, so-called because it is encoded by the immediate early growth response gene, Egr1, is rapidly induced by growth factors to transduce the proliferative signal. The induction of Egr1 by external stimuli is generally transient but appears to be sustained in some prostate tumor cell lines and tumors, suggesting that Egr1 stimulates tumor cell growth. In contradiction, in breast, lung and brain tumors, Egr1 expression is often absent or reduced and when re-expressed, results in growth suppression. Re-expression of Egr1 in tumor cells also leads to antiapoptotic activity, which would encourage tumor cell survival. Egr1 is also required for, or stimulates, the differentiation of several cell types. Another contradiction is that after stress stimuli to some cell types, Egr1 is required for programmed cell death or apoptosis in both normal and tumor cells. Egr1 also plays a role in tumor progression, through the hypoxic signal generated in growing tumors. Egr1 is highly induced under these conditions and its activities stimulate angiogenesis and improved survival of tumor cells. How this large agenda can be achieved lies in the choice of Egr1 target genes, and varying patterns of coordinated expression have been described, but the mechanisms for this choice are not clear. This review points to areas where research should be focussed.
La Jolla Cancer Research Center, The Burnham Institute
10901 North Torrey Pines Rd.
La Jolla, CA 92037 (USA)
Tel. +1 858 646 3137, Fax +1 858 646 3198, E-Mail firstname.lastname@example.org
Received: Received: September 21, 2001
Accepted after revision: December 10, 2001
Number of Print Pages : 10
Number of Figures : 1, Number of Tables : 1, Number of References : 141
Tumor Biology (Tumor Markers and Translational Cancer Research)
Founded 1980 as ‘Oncodevelopmental Biology and Medicine’ by the ISOBM, continued 1984–1986 as ‘Tumour Biology’
The Journal of the International Society for Oncodevelopmental Biology and Medicine (ISOBM)
Vol. 23, No. 2, Year 2002 (Cover Date: March-April 2002 (Released June 2002))
Journal Editor: T. Stigbrand, Umeå; Managing Editor: P.D. Rye, Oslo
ISSN: 1010–4283 (print), 1423–0380 (Online)
For additional information: http://www.karger.com/journals/tbi