A p21-ZEB1 Complex Inhibits Epithelial-Mesenchymal Transition through the MicroRNA 183-96-182 Cluster

Abstract

The tumor suppressor p21 acts as a cell cycle inhibitor and has also been shown to regulate gene expression by functioning as a transcription corepressor. Here, we identified p21-regulated microRNAs (miRNAs) by sequencing small RNAs from isogenic p21^+/+ and p21^−/− cells. Three abundant miRNA clusters, miR-200b-200a-429, miR-200c-141, and miR-183-96-182, were downregulated in p21-deficient cells. Consistent with the known function of the miR-200 family and p21 in inhibition of the epithelial-mesenchymal transition (EMT), we observed EMT upon loss of p21 in multiple model systems. To explore a role of the miR-183-96-182 cluster in EMT, we identified its genome-wide targets and found that miR-183 and miR-96 repressed common targets, including SLUG, ZEB1, ITGB1, and KLF4. Reintroduction of miR-200, miR-183, or miR-96 in p21^−/− cells inhibited EMT, cell migration, and invasion. Conversely, antagonizing miR-200 and miR-183-96-182 cluster miRNAs in p21^+/+ cells increased invasion and elevated the levels of VIM, ZEB1, and SLUG mRNAs. Furthermore, we found that p21 forms a complex with ZEB1 at the miR-183-96-182 cluster promoter to inhibit transcriptional repression of this cluster by ZEB1, suggesting a reciprocal feedback loop.

SUPPLEMENTAL MATERIAL

Supplemental material for this article may be found at http://dx.doi.org/10.1128/MCB.01043-13.

ACKNOWLEDGMENTS

Ashish Lal was supported by the Intramural Research Program of the National Institutes of Health, National Cancer Institute, Center for Cancer Research. Thomas Brabletz was supported by the DFG (BR 1399/6-1, SFB 850/B2, and SFB992/C6) and the Deutsche Krebshilfe (grant no. 109430). Sudha Sharma was supported by the National Institute of General Medical Sciences of the National Institutes of Health under award number SC1GM093999.

We thank K. Prasanth (University of Illinois at Urbana-Champaign) and Marshall Thomas (Harvard University) for their comments on the manuscript. The HCT116 isogenic cell lines were a kind gift from Bert Vogelstein (Johns Hopkins University), and the Ago2 antibody was a kind gift from Zissimos Mourelators (University of Pennsylvania).