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Vulin et al. PATCHED1 and radiosensitivity IJROBP Oct 2018.pdf (1.16 MB)

Severe PATCHED1 deficiency in cancer-prone Gorlin patient cells results in intrinsic radiosensitivity

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posted on 2023-06-09, 15:34 authored by Adeline Vulin, Melissa Sedkaoui, Sandra Moratille, Nicolas Sevenet, Pascal Soularne, Odile Rigaud, Laure Guibbal, Joshua Dulong, Penny Jeggo, Jean-François Deleuze, Jérôme Lamartine, Martin Martin
PURPOSE: Gorlin syndrome (or basal-cell nevus syndrome) is a cancer-prone genetic disease in which hypersusceptibility to secondary cancer and tissue reaction after radiation therapy is debated, as is increased radiosensitivity at cellular level. Gorlin syndrome results from heterozygous mutations in the PTCH1 gene for 60% of patients, and we therefore aimed to highlight correlations between intrinsic radiosensitivity and PTCH1 gene expression in fibroblasts from adult patients with Gorlin syndrome. METHODS AND MATERIALS: The radiosensitivity of fibroblasts from 6 patients with Gorlin syndrome was determined by cell-survival assay after high (0.5-3.5 Gy) and low (50-250 mGy) ?-ray doses. PTCH1 and DNA damage response gene expression was characterized by real-time polymerase chain reaction and Western blotting. DNA damage and repair were investigated by ?H2AX and 53BP1 foci assay. PTCH1 knockdown was performed in cells from healthy donors by using stable RNA interference. Gorlin cells were genotyped by 2 complementary sequencing methods. RESULTS: Only cells from patients with Gorlin syndrome who presented severe deficiency in PATCHED1 protein exhibited a significant increase in cellular radiosensitivity, affecting cell responses to both high and low radiation doses. For 2 of the radiosensitive cell strains, heterozygous mutations in the 5' end of PTCH1 gene explain PATCHED1 protein deficiency. In all sensitive cells, DNA damage response pathways (ATM, CHK2, and P53 levels and activation by phosphorylation) were deregulated after irradiation, whereas DSB repair recognition was unimpaired. Furthermore, normal cells with RNA interference-mediated PTCH1 deficiency showed reduced survival after irradiation, directly linking this gene to high- and low-dose radiosensitivity. CONCLUSIONS: In the present study, we show an inverse correlation between PTCH1 expression level and cellular radiosensitivity, suggesting an explanation for the conflicting results previously reported for Gorlin syndrome and possibly providing a basis for prognostic screens for radiosensitive patients with Gorlin syndrome and PTCH1 mutations.

History

Publication status

  • Published

File Version

  • Published version

Journal

International Journal of Radiation Oncology - Biology - Physics

ISSN

0360-3016

Publisher

Elsevier

Issue

2

Volume

102

Page range

417-425

Department affiliated with

  • Sussex Centre for Genome Damage Stability Publications

Research groups affiliated with

  • Genome Damage and Stability Centre Publications

Full text available

  • Yes

Peer reviewed?

  • Yes

Legacy Posted Date

2018-10-19

First Open Access (FOA) Date

2018-10-19

First Compliant Deposit (FCD) Date

2018-10-19

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