Ranieri, Michela (2015) Regulation of p14ARF tumor suppressor activities and functions. [Tesi di dottorato]

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Item Type: Tesi di dottorato
Resource language: English
Title: Regulation of p14ARF tumor suppressor activities and functions
Creators:
CreatorsEmail
Ranieri, Michelamikiran1985@libero.it
Date: 31 March 2015
Number of Pages: 74
Institution: Università degli Studi di Napoli Federico II
Department: Medicina Molecolare e Biotecnologie Mediche
Scuola di dottorato: Medicina molecolare
Dottorato: Genetica e medicina molecolare
Ciclo di dottorato: 27
Coordinatore del Corso di dottorato:
nomeemail
Nitsch, Luciolucio.nitsch@unina.it
Tutor:
nomeemail
La Mantia, GirolamaUNSPECIFIED
Date: 31 March 2015
Number of Pages: 74
Keywords: ARF, Phosphorylation
Settori scientifico-disciplinari del MIUR: Area 05 - Scienze biologiche > BIO/18 - Genetica
Aree tematiche (7° programma Quadro): SALUTE e TUTELA DEL CONSUMATORE > Biotecnologie, strumenti e tecnologie generiche per la salute umana
Date Deposited: 11 Apr 2015 09:16
Last Modified: 13 Oct 2015 07:41
URI: http://www.fedoa.unina.it/id/eprint/10408
DOI: 10.6092/UNINA/FEDOA/10408

Collection description

The ARF protein is encoded by the alternative reading frame of the INK4a locus, one of the most frequent sites of genetic loss in human cancers. The ARF tumor suppressor function, as a sensor of hyper-proliferative stimuli, is to restrict cell proliferation through both p53-dependent and independent pathways. However, few studies started to address the possibility that ARF might promote the survival of subsets of tumors. In the past years, intensive studies have been focused not only on ARF activation at transcriptional level but also on the mechanisms regulating ARF protein turnover. Here we show that p14ARF is a PKC target. In fact, PKC activation mediates phosphorylation and stabilization of ARF endogenously expressed protein. Moreover, a phosphomimetic ARF mutant accumulates in the cytoplasm and, interestingly, despite the ability to stabilize p53 and bind MDM2, is not able to efficiently block cell growth in both human and mouse cell lines. These data could be interpreted as a way of cancer cells to escape ARF surveillance in tumorigenesis, but they might also indicate that ARF phosphorylation in tumor cells could be a mean to sustain tumor progression by conferring pro-survival properties to the cells. We thus explored the role of endogenously expressed ARF protein in some tumor and stabilized cell lines by knocking down ARF expression by siRNA. Unspectedly, we observed a block of cell proliferation and induction of DAPK mediated p53-dependent apoptosis in ARF depleted Hela and HaCat cells. Our results suggest that ARF might have a pro-survival role depending on cellular context.

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