p53-Responsive micrornas 192 and 215 are capable of inducing cell cycle arrest.
microRNAs provide a novel layer of regulation for gene expression by interfering with the stability and/or translation of specific target mRNAs. Overall levels of microRNAs are frequently down-regulated in cancer cells, and reducing general microRNA processing increases cancerogenesis in transgenic models, suggesting that at least some microRNAs might act as effectors in tumor suppression. Accordingly, the tumor suppressor p53 up-regulates miR-34a, a microRNA that contributes to apoptosis and acute senescence. Here, we used array hybridization to find that p53 induces two additional, mutually related clusters of microRNAs, leading to the up-regulation of miR-192, miR-194, and miR-215. The same microRNAs were detected at high levels in normal colon tissue but were severely reduced in many colon cancer samples. On the other hand, miR-192 and its cousin miR-215 can each contribute to enhanced CDKN1A/p21 levels, colony suppression, cell cycle arrest, and cell detachment from a solid support. These effects were partially dependent on the presence of wild-type p53. Antagonizing endogenous miR-192 attenuated 5-fluorouracil-induced accumulation of p21. Hence, miR-192 and miR-215 can act as effectors as well as regulators of p53; they seem to suppress cancerogenesis through p21 accumulation and cell cycle arrest.
Braun
Christian J
CJ
Department of Molecular Oncology, Göttingen Center of Molecular Biosciences, University of Göttingen, Göttingen, Germany.
Zhang
Xin
X
Savelyeva
Irina
I
Wolff
Sonja
S
Moll
Ute M
UM
Schepeler
Troels
T
Ørntoft
Torben F
TF
Andersen
Claus L
CL
Dobbelstein
Matthias
M
D001859:Bone Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D002448:Cell Adhesion / Q000235:genetics; D002453:Cell Cycle / Q000235:genetics; D045744:Cell Line, Tumor; D003110:Colonic Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000096:biosynthesis / Q000235:genetics; D016158:Genes, p53; D045325:HCT116 Cells; D019073:HT29 Cells; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D035683:MicroRNAs / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000235:genetics; D009369:Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology*; D020411:Oligonucleotide Array Sequence Analysis; D012516:Osteosarcoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D010879:Piperazines / Q000494:pharmacology; D051736:Proto-Oncogene Proteins c-mdm2 / Q000378:metabolism; D014162:Transfection; D016159:Tumor Suppressor Protein p53 / Q000235:genetics* / Q000378:metabolism; D015854:Up-Regulation
C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D007093:Imidazoles; D035683:MicroRNAs; D010879:Piperazines; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; C482205:nutlin 3; C497206:MDM2 protein, human; D051736:Proto-Oncogene Proteins c-mdm2