Arya AK, El-Fert A, Devling T, Eccles RM, Aslam MA, Rubbi CP, Vlatković N, Fenwick J, Lloyd BH, Sibson DR, Jones TM, Boyd MT. Nutlin-3, the small-molecule inhibitor of MDM2, promotes senescence and radiosensitises laryngeal carcinoma cells harbouring wild-type p53.
Br J Cancer 2010;
103:186-95. [PMID:
20588277 PMCID:
PMC2906734 DOI:
10.1038/sj.bjc.6605739]
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Abstract
BACKGROUND
Primary radiotherapy (RT) is a mainstay of treatment for laryngeal squamous cell carcinoma (LSCC). Although the cure rates for early (T1) vocal cord tumours are high, RT proves ineffective in up to a third of T3 carcinomas. Moreover, RT is associated with debilitating early- and late-treatment-related toxicity, thus finding means to de-escalate therapy, while retaining/augmenting therapeutic effectiveness, is highly desirable. p53 is a key mediator of radiation responses; we therefore investigated whether Nutlin-3, a small-molecule inhibitor of MDM2 (mouse double minute 2; an essential negative regulator of p53), might radiosensitise LSCC cells.
METHODS
We performed clonogenic assays to measure radiosensitivity in a panel of LSCC cell lines (for which we determined p53 mutational status) in the presence and absence of Nutlin-3.
RESULTS
LSCC cells harbouring wild-type p53 were significantly radiosensitised by Nutlin-3 (P<0.0001; log-rank scale), and displayed increased cell cycle arrest and significantly increased senescence (P<0.001) in the absence of increased apoptosis; thus, our data suggest that senescence may mediate this increased radiosensitivity.
CONCLUSION
This is the first study showing Nutlin-3 as an effective radiosensitiser in LSCC cells that retain wild-type p53. The clinical application of Nutlin-3 might improve local recurrence rates or allow treatment de-escalation in these patients.
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