E2F-1 up-regulates c-Myc and p14(ARF) and induces apoptosis in colon cancer cells.
Clin Cancer Res
; 7(11): 3590-7, 2001 Nov.
Article
de En
| MEDLINE
| ID: mdl-11705881
ABSTRACT
Although overexpression of E2F-1 can induce apoptosis in a variety of tumor cell lines, the mechanisms by which E2F-1 induces apoptosis remain ambiguous. In this study, we examine the ability of E2F-1 to induce apoptosis in colon cancer and the molecular mechanisms underlying E2F-1-mediated apoptosis. HT-29 and SW-620 colon adenocarcinoma cells (both mutant p53) were treated by mock infection or adenoviral vectors Ad5CMV (empty vector), Ad5CMVLacZ (beta-galactosidase), and Ad5CMVE2F-1 (E2F-1) at multiplicity of infection of 100. Western blot analysis confirmed marked overexpression of E2F-1 in both cell lines. By 5 days after infection, E2F-1 overexpression resulted in >25-fold reduction in cell growth and >90% loss of cell viability in both cell lines. Cell cycle analysis of Ad-E2F-1-infected cells revealed an increase in G(2)/M and sub-G(1) populations. By in situ terminal deoxynucleotidyl transferase (Tdt)-mediated nick end labeling analysis, evidence of apoptosis was observed including internucleosomal DNA fragmentation and the formation of apoptotic bodies. In addition, caspase-3 and poly(ADP-ribose) polymerase apoptotic fragments were detected by 48 h after treatment with Ad-E2F-1. Of mechanistic importance, overexpression of E2F-1 caused a G(2)/M arrest followed by increased levels of c-Myc and p14(ARF) proteins. Additionally, expression of the antiapoptotic Bcl-2 family member Mcl-1 was down-regulated in E2F-1-overexpressing cells. In conclusion, E2F-1 overexpression initiates apoptosis and suppresses growth in HT-29 and SW620 colon adenocarcinoma cells. Overexpression of E2F-1 triggers apoptosis and is associated with up-regulation of c-Myc and p14(ARF) proteins and down-regulation of Mcl-1. Therefore, E2F-1 is a potentially active gene therapy agent for the treatment of colon cancer.
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Collection:
01-internacional
Base de données:
MEDLINE
Sujet principal:
Facteurs de transcription
/
Protéines proto-oncogènes c-myc
/
Apoptose
/
Tumeurs du côlon
/
Protéines du cycle cellulaire
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Protéine p14(ARF) suppresseur de tumeur
/
Protéines de liaison à l'ADN
Limites:
Humans
Langue:
En
Journal:
Clin Cancer Res
Sujet du journal:
NEOPLASIAS
Année:
2001
Type de document:
Article
Pays d'affiliation:
États-Unis d'Amérique