p63 Sustains self-renewal of mammary cancer stem cells through regulation of Sonic Hedgehog signaling.
The predominant p63 isoform, ΔNp63, is a master regulator of normal epithelial stem cell (SC) maintenance. However, in vivo evidence of the regulation of cancer stem cell (CSC) properties by p63 is still limited. Here, we exploit the transgenic MMTV-ErbB2 (v-erb-b2 avian erythroblastic leukemia viral oncogene homolog 2) mouse model of carcinogenesis to dissect the role of p63 in the regulation of mammary CSC self-renewal and breast tumorigenesis. ErbB2 tumor cells enriched for SC-like properties display increased levels of ΔNp63 expression compared with normal mammary progenitors. Down-regulation of p63 in ErbB2 mammospheres markedly restricts self-renewal and expansion of CSCs, and this action is fully independent of p53. Furthermore, transplantation of ErbB2 progenitors expressing shRNAs against p63 into the mammary fat pads of syngeneic mice delays tumor growth in vivo. p63 knockdown in ErbB2 progenitors diminishes the expression of genes encoding components of the Sonic Hedgehog (Hh) signaling pathway, a driver of mammary SC self-renewal. Remarkably, p63 regulates the expression of Sonic Hedgehog (Shh), GLI family zinc finger 2 (Gli2), and Patched1 (Ptch1) genes by directly binding to their gene regulatory regions, and eventually contributes to pathway activation. Collectively, these studies highlight the importance of p63 in maintaining the self-renewal potential of mammary CSCs via a positive modulation of the Hh signaling pathway.
Biochemistry Laboratory, Istituto Dermopatico dell'Immacolata, Istituto di Ricovero e Cura a Carattere Scientifico, Department of Experimental Medicine and Surgery, University of Rome "Tor Vergata," 00133 Rome, Italy;
Elisa Maria
EM
Memmi
Biochemistry Laboratory, Istituto Dermopatico dell'Immacolata, Istituto di Ricovero e Cura a Carattere Scientifico, Department of Experimental Medicine and Surgery, University of Rome "Tor Vergata," 00133 Rome, Italy;
Anna Giulia
AG
Sanarico
Biochemistry Laboratory, Istituto Dermopatico dell'Immacolata, Istituto di Ricovero e Cura a Carattere Scientifico, Department of Experimental Medicine and Surgery, University of Rome "Tor Vergata," 00133 Rome, Italy;
Arianna
A
Giacobbe
Department of Biochemical Sciences, Institute of Cellular Biology and Neurobiology, Consiglio Nazionale delle Ricerche, 00015 Rome, Italy;
Angelo
A
Peschiaroli
Biochemistry Laboratory, Istituto Dermopatico dell'Immacolata, Istituto di Ricovero e Cura a Carattere Scientifico, Department of Experimental Medicine and Surgery, University of Rome "Tor Vergata," 00133 Rome, Italy;
Valentina
V
Frezza
Department of Experimental Oncology, European Institute of Oncology, 20141 Milan, Italy;
Angelo
A
Cicalese
Institute of Molecular Oncology (IFOM) of the Italian Foundation for Cancer Research (FIRC), 20139 Milan, Italy;
Federica
F
Pisati
Department of Experimental Oncology, European Institute of Oncology, 20141 Milan, Italy;
Daniela
D
Tosoni
Department of Molecular Developmental Biology, Faculty of Science, Radboud University, and Department of Human Genetics, Radboud University Nijmegen Medical Centre, 6525 GA, Nijmegen, The Netherlands;
Huiqing
H
Zhou
Functional Genomics of Cancer Unit, Division of Molecular Oncology, San Raffaele Scientific Institute, 20132 Milan, Italy;
Giovanni
G
Tonon
Medical Research Council, Toxicology Unit, Leicester University, Leicester LE1 9HN, United Kingdom; and.
Alexey
A
Antonov
Biochemistry Laboratory, Istituto Dermopatico dell'Immacolata, Istituto di Ricovero e Cura a Carattere Scientifico, Department of Experimental Medicine and Surgery, University of Rome "Tor Vergata," 00133 Rome, Italy; Medical Research Council, Toxicology Unit, Leicester University, Leicester LE1 9HN, United Kingdom; and melino@uniroma2.it piergiuseppe.pelicci@ieo.eu bernasso@uniroma2.it.
Gerry
G
Melino
Department of Experimental Oncology, European Institute of Oncology, 20141 Milan, Italy; Department of Health Sciences, Milan University, 20142 Milan, Italy melino@uniroma2.it piergiuseppe.pelicci@ieo.eu bernasso@uniroma2.it.
Pier Giuseppe
PG
Pelicci
Biochemistry Laboratory, Istituto Dermopatico dell'Immacolata, Istituto di Ricovero e Cura a Carattere Scientifico, Department of Experimental Medicine and Surgery, University of Rome "Tor Vergata," 00133 Rome, Italy; Department of Experimental Oncology, European Institute of Oncology, 20141 Milan, Italy; melino@uniroma2.it piergiuseppe.pelicci@ieo.eu bernasso@uniroma2.it.
Francesca
F
Bernassola
D000818:Animals; D049109:Cell Proliferation; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D053823:Hedgehog Proteins / Q000378:metabolism*; D008321:Mammary Glands, Animal / Q000473:pathology*; D008325:Mammary Neoplasms, Experimental / Q000235:genetics / Q000473:pathology; D008810:Mice, Inbred C57BL; D014411:Neoplastic Stem Cells / Q000378:metabolism* / Q000473:pathology*; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
D053823:Hedgehog Proteins; D010750:Phosphoproteins; D018719:Erb-b2 Receptor Tyrosine Kinases; D015534:Trans-Activators; C465570:Shh protein, mouse; C486419:Trp63 protein, mouse; C524056:Erbb2 protein, mouse
breast cancer; mammary stem cells; p53 family