p21CIP1 attenuates Ras- and c-Myc-dependent breast tumor epithelial mesenchymal transition and cancer stem cell-like gene expression in vivo.

Abstract

p21(CIP1/WAF1) is a downstream effector of tumor suppressors and functions as a cyclin-dependent kinase inhibitor to block cellular proliferation. Breast tumors may derive from self-renewing tumor-initiating cells (BT-ICs), which contribute to tumor progression, recurrence, and therapy resistance. The role of p21(CIP1) in regulating features of tumor stem cells in vivo is unknown. Herein, deletion of p21(CIP1), which enhanced the rate of tumorigenesis induced by mammary-targeted Ha-Ras or c-Myc, enhanced gene expression profiles and immunohistochemical features of epithelial mesenchymal transition (EMT) and putative cancer stem cells in vivo. Silencing of p21(CIP1) enhanced, and expression of p21(CIP1) repressed, features of EMT in transformed immortal human MEC lines. p21(CIP1) attenuated oncogene-induced BT-IC and mammosphere formation. Thus, the in vitro cell culture assays reflect the changes observed in vivo in transgenic mice. These findings establish a link between the loss of p21(CIP1) and the acquisition of breast cancer EMT and stem cell properties in vivo.

• Authors: Manran Liu, Mathew C Casimiro, Chenguang Wang, L Andrew Shirley, Xuanmao Jiao, Sanjay Katiyar, Xiaoming Ju, Zhiping Li, Zuoren Yu, Jie Zhou, Michael Johnson, Paolo Fortina, Terry Hyslop, Jolene J Windle, Richard G Pestell
• Journal: Proceedings of the National Academy of Sciences of the United States of America (Proc Natl Acad Sci U S A) Vol. 106 Issue 45 Pg. 19035-9 (Nov 10 2009) ISSN: 1091-6490 [Electronic] United States
• PMID: 19858489 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• Cdkn1a protein, mouse
• Cyclin-Dependent Kinase Inhibitor p21
• Myc protein, mouse
• Proto-Oncogene Proteins c-myc
• Proto-Oncogene Proteins p21(ras)

Topics

• Animals
• Breast Neoplasms (metabolism)
• Cell Line, Tumor
• Cell Transformation, Neoplastic (metabolism)
• Cyclin-Dependent Kinase Inhibitor p21 (metabolism)
• Epithelial Cells (metabolism, pathology)
• Gene Expression Regulation, Neoplastic
• Humans
• Immunohistochemistry
• Mice
• Mice, Transgenic
• Neoplastic Stem Cells (cytology, metabolism)
• Oligonucleotide Array Sequence Analysis
• Proto-Oncogene Proteins c-myc (metabolism)
• Proto-Oncogene Proteins p21(ras) (metabolism)
• Reverse Transcriptase Polymerase Chain Reaction