The tumor-suppressive functions of the human INK4A locus.
The INK4A locus is often inactivated in human cancer. INK4A encodes for p14ARF and p16INK4A that inhibit growth through p53 and pRb, respectively. We used RNA interference vectors in transformation assays of human primary cells to analyze tumor-suppressive functions. We first show that a concerted inactivation of pRb and p53 is required for transformation. We then demonstrate that loss of p14ARF enhances growth in a p53-dependent manner but has little tumorigenic effect. In contrast, suppression of p16INK4A expression does not affect cellular proliferation but synergizes with p53 loss to accelerate growth and cause transformation. Our results delineate the functions of the human INK4A genes in normal and tumorigenic growth.
Division of Tumor Biology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands.
P Mathijs
PM
Voorhoeve
Reuven
R
Agami
D002455:Cell Division / Q000502:physiology*; D002478:Cells, Cultured; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000235:genetics / Q000378:metabolism*; D005347:Fibroblasts / Q000378:metabolism; D017353:Gene Deletion; D011905:Genes, ras / Q000235:genetics / Q000502:physiology; D006367:HeLa Cells; D006801:Humans; D009154:Mutation; D034741:RNA, Small Interfering / Q000378:metabolism; D016160:Retinoblastoma Protein / Q000378:metabolism; D012867:Skin / Q000378:metabolism; D025803:Tumor Suppressor Protein p14ARF / Q000235:genetics / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
D019941:Cyclin-Dependent Kinase Inhibitor p16; D034741:RNA, Small Interfering; D016160:Retinoblastoma Protein; D025803:Tumor Suppressor Protein p14ARF; D016159:Tumor Suppressor Protein p53