title: p53 Stabilization induces cell growth inhibition and affects IGF2 pathway in response to radiotherapy in adrenocortical cancer cells.
abstract: Adrenocortical carcinoma (ACC) is a very rare endocrine tumour, with variable prognosis, depending on tumour stage and time of diagnosis. However, it is generally fatal, with an overall survival of 5 years from detection. Radiotherapy usefulness for ACC treatment has been widely debated and seems to be dependent on molecular alterations, which in turn lead to increased radio-resistance. Many studies have shown that p53 loss is an important risk factor for malignant adrenocortical tumour onset and it has been reported that somatic mutations in TP53 gene occur in 27 to 70% of adult sporadic ACCs. In this study, we investigated the role of somatic mutations of the TP53 gene in response to ionizing radiation (IR). We studied the status of p53 in two adrenocortical cell lines, H295R and SW-13, harbouring non-functioning forms of this protein, owing to the lack of exons 8 and 9 and a point mutation in exon 6, respectively. Moreover, these cell lines show high levels of p-Akt and IGF2, especially H295R. We noticed that restoration of p53 activity led to inhibition of growth after transient transfection of cells with wild type p53. Evaluation of their response to IR in terms of cell proliferation and viability was determined by means of cell count and TUNEL assay.(wt)p53 over-expression also increased cell death by apoptosis following radiation in both cell lines. Moreover, RT-PCR and Western blotting analysis of some p53 target genes, such as BCL2, IGF2 and Akt demonstrated that p53 activation following IR led to a decrease in IGF2 expression. This was associated with a reduction in the active form of Akt. Taken together, these results highlight the role of p53 in response to radiation of ACC cell lines, suggesting its importance as a predictive factor for radiotherapy in malignant adrenocortical tumours cases.
authors.affiliation: Endocrinology, Department of Clinical and Molecular Medicine, Sant'Andrea Hospital, Faculty of Medicine and Psychology "Sapienza" University of Rome, Rome, Italy.
authors.forename: Camilla
authors.initials: C
authors.lastname: Sampaoli
authors.forename: Lidia
authors.initials: L
authors.lastname: Cerquetti
authors.forename: Randa El
authors.initials: RE
authors.lastname: Gawhary
authors.forename: Barbara
authors.initials: B
authors.lastname: Bucci
authors.forename: Donatella
authors.initials: D
authors.lastname: Amendola
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Marchese
authors.forename: Silvia
authors.initials: S
authors.lastname: Misiti
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Novelli
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Toscano
authors.forename: Antonio
authors.initials: A
authors.lastname: Stigliano
mesh_terms: D018268:Adrenocortical Carcinoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology* / Q000532:radiotherapy*; D000595:Amino Acid Sequence; D001483:Base Sequence; D016923:Cell Death / Q000528:radiation effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000528:radiation effects; D004789:Enzyme Activation / Q000528:radiation effects; D015972:Gene Expression Regulation, Neoplastic / Q000528:radiation effects; D006801:Humans; D020287:In Situ Nick-End Labeling; D007335:Insulin-Like Growth Factor II / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D055550:Protein Stability / Q000528:radiation effects; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011839:Radiation, Ionizing; D017422:Sequence Analysis, DNA; D015398:Signal Transduction / Q000528:radiation effects; D016159:Tumor Suppressor Protein p53 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D012333:RNA, Messenger; D016159:Tumor Suppressor Protein p53; D007335:Insulin-Like Growth Factor II; D051057:Proto-Oncogene Proteins c-akt