Blockage of melatonin receptors impairs p53-mediated prevention of DNA damage accumulation

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Published on Monday, 28 July 2014

Abstract

Melatonin has been known to be a chemopreventive agent since its levels inversely correlate with the risk of developing cancer.

We have recently shown that melatonin induces p38-dependent phosphorylation of both p53 and histone H2AX. This is associated with a p53-mediated increase in repair of both endogenous and chemotherapy-induced DNA damage. In addition, the inhibition of p38 activities impairs melatonin's capability to induce a p53-dependent DNA damage response and thus its ability to maintain genome integrity.

Since melatonin-induced p53 phosphorylation requires an intact p38 phosphorylation cascade and p38 can be activated by G proteins, we supposed that melatonin's activities could be mediated by its G-protein-coupled membrane receptors, MT1 and MT2.

Here, we show that the activation of the p53-dependent DNA damage response by melatonin is indeed mediated by MT1 and MT2.

As a result, the absence of either receptor impairs melatonin's ability to reduce both cell proliferation and clonogenic potential of cancer cells. In addition, this causes an impairment of the p53-dependent DNA damage response.

By providing molecular insight, our findings might have translational impact, suggesting the involvement of melatonin receptors in tumorigenesis.

 

 

Supplementary Figures can be found here.

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See also About Melatonin.