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Thymine dimer repair in fibroblasts of patients with dysplastic naevus syndrome (DNS)
1Dept of Research, University Clinics, Kantonsspital, Basel, Switzerland.
Abstract:
Dysplastic naevus syndrome (DNS) is frequently observed in association with familial melanoma and xeroderma pigmentosum (XP), but the role of UV-light in the development of DNS has not been elucidated. Previous work has shown that UV-induced unscheduled DNA synthesis is associated with the early loss of antigenicity observed in immunoassays using a monoclonal antibody specific for thymine-thymine dimers. We now show that the rate of loss of antigenicity, which reflects the relative amount of bound antibody, observed during the first 60 min following 10 Jm-2 UVC irradiation is significantly reduced (p = 0.02) in cultures of fibroblasts from 7 out of 8 DNS patients compared with the results from cells of a group of 30 healthy volunteers. This observation suggests an early event in excision repair is altered in the majority of DNS patients.
Insights
Dysplastic naevus syndrome (DNS) patients show altered DNA repair after UV exposure. This suggests a potential link between UV sensitivity and DNS development, impacting melanoma risk.
Area of Science:
- Dermatology
- Molecular Biology
- Genetics
Background:
- Dysplastic naevus syndrome (DNS) is linked to familial melanoma and xeroderma pigmentosum (XP).
- The influence of UV radiation on DNS development remains unclear.
- UV-induced DNA damage and repair mechanisms are critical in skin cancer etiology.
Purpose of the Study:
- To investigate the role of UV light in the development of Dysplastic Naevus Syndrome (DNS).
- To assess DNA repair efficiency in fibroblasts from DNS patients following UV irradiation.
- To explore potential alterations in early excision repair pathways in DNS.
Main Methods:
- Fibroblast cultures from 8 DNS patients and 30 healthy volunteers were used.
- Cells were exposed to 10 Jm-2 UVC irradiation.
- The rate of loss of antigenicity, indicating DNA repair, was measured using monoclonal antibodies against thymine-thymine dimers.
Main Results:
- A significantly reduced rate of loss of antigenicity was observed in 7 out of 8 DNS patient fibroblast cultures within 60 minutes post-UVC irradiation (p = 0.02).
- This reduction suggests a slower or altered DNA repair process compared to healthy controls.
- The findings point towards an early defect in the DNA excision repair pathway in the majority of DNS patients.
Conclusions:
- The study indicates an alteration in an early event of DNA excision repair in most Dysplastic Naevus Syndrome patients.
- This finding suggests that impaired UV DNA repair may contribute to the pathogenesis of DNS and its association with melanoma.
- Further research into UV sensitivity and DNA repair mechanisms in DNS is warranted.