Abstract 5045: Critical role of zinc finger protein 521 in the control of growth, clonogenicity and tumorigenic potential of medulloblastoma cells.

Abstract

Abstract The stem cell-associated transcription co-factor ZNF521 has been implicated in the control of haematopoietic, osteogenic and neural progenitors. Very high expression of this factor is present in cerebellum and particularly in the granule layer of neonatal cerebellum, that contains candidate cells-of-origin of medulloblastoma. Here we have explored the possible involvement of ZNF521 in the development of this tumour. As an experimental system we used the human medulloblastoma cell line, DAOY, and primary cells from medulloblastomas occurring in Ptc1-/+ mice. To investigate the effect of ZNF521 on the growth and tumourigenic potential of these cells, its expression was modulated using lentiviral vectors carrying the ZNF521 cDNA, or containing shRNAs that silence its expression. Enforced overexpression of ZNF521 in DAOY cells, that normally produce relatively low amounts of this protein, was associated with a significant increase in their proliferation rate. This was mirrored by an increase in the ability to grow as spheroids and clonogenicity in single-cell cultures and in semisolid media, and accompanied by an enhanced migratory capacity in wound-healing assays. Finally, ZNF521-expressing DAOY cells demonstrated a greatly enhanced tumourigenic potential in nude mice. All these activities required the presence of an N-terminal domain of ZNF521 that recruits the nucleosome remodeling and histone deacetylase (NuRD) complex. Consistently with the effects of ZNF521 overexpression in DAOY, silencing of Zfp521 in Ptc1-/+ medulloblastoma cells resulted in a drastic decrease in their proliferation and tumourigenic potential, lending further support to the notion that zinc finger protein 521 may contribute to the generation and/or maintenance of the cancer-initiating cell compartment in this cancer. Preliminary experiments detected a selective up-regulation of HES5 mRNA in DAOY overexpressing ZNF521, raising the possibility that some of the effects illustrated here may at least in part be mediated by the co-operation of ZNF521 with the Notch pathway. Citation Format: Raffaella Spina, Gessica Filocamo, Enrico Iaccino, Stefania Scicchitano, Michela Lupia, Emanuela Chiarella, Tiziana Mega, Daniela Pelaggi, Maria Mesuraca, Eli E. Bar, Heather M. Bond, Charles G. Eberhart, Christian Steinkuhler, Gianni Morrone. Critical role of zinc finger protein 521 in the control of growth, clonogenicity and tumorigenic potential of medulloblastoma cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5045. doi:10.1158/1538-7445.AM2013-5045 Note: This abstract was not presented at the AACR Annual Meeting 2013 because the presenter was unable to attend.