A functional screen identifies hDRIL1 as an oncogene that rescues RAS-induced senescence.
Primary fibroblasts respond to activated H-RAS(V12) by undergoing premature arrest, which resembles replicative senescence. This irreversible 'fail-safe mechanism' requires p19(ARF), p53 and the Retinoblastoma (Rb) family: upon their disruption, RAS(V12)-expressing cells fail to undergo senescence and continue to proliferate. Similarly, co-expression of oncogenes such as c-MYC or E1A rescues RAS(V12)-induced senescence. To identify novel genes that allow escape from RAS(V12)-induced senescence, we designed an unbiased, retroviral complementary DNA library screen. We report on the identification of DRIL1, the human orthologue of the mouse Bright and Drosophila dead ringer transcriptional regulators. DRIL1 renders primary murine fibroblasts unresponsive to RAS(V12)-induced anti-proliferative signalling by p19(ARF)/p53/p21(CIP1), as well as by p16(INK4a). In this way, DRIL1 not only rescues RAS(V12)-induced senescence but also causes these fibroblasts to become highly oncogenic. Furthermore, DRIL1 immortalizes mouse fibroblasts, in the presence of high levels of p16(INK4a). Immortalization by DRIL1, whose product binds the pRB-controlled transcription factor E2F1 (ref. 8), is correlated with induction of E2F1 activity. Correspondingly, DRIL1 induces the E2F1 target Cyclin E1, overexpression of which is sufficient to trigger escape from senescence. Thus, DRIL1 disrupts cellular protection against RAS(V12)-induced proliferation downstream of the p19(ARF)/p53 pathway.
Peeper
Daniel S
DS
Division of Molecular Carcinogenesis and Center for Biomedical Genetics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands.
Shvarts
Avi
A
Brummelkamp
Thijn
T
Douma
Sirith
S
Koh
Eugene Y
EY
Daley
George Q
GQ
Bernards
René
R
D000818:Animals; D002478:Cells, Cultured; D016922:Cellular Senescence / Q000502:physiology*; D019927:Cyclin E / Q000235:genetics / Q000378:metabolism; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D011905:Genes, ras / Q000235:genetics*; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D009857:Oncogenes; D015398:Signal Transduction / Q000502:physiology; D015534:Trans-Activators; D014157:Transcription Factors; D025803:Tumor Suppressor Protein p14ARF / Q000378:metabolism
C490798:ARID3A protein, human; C097532:Arid3a protein, mouse; C417743:Cdkn2a protein, mouse; D019927:Cyclin E; D019941:Cyclin-Dependent Kinase Inhibitor p16; D004268:DNA-Binding Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D025803:Tumor Suppressor Protein p14ARF