The p53 tumor suppressor gene and precursor of addiction to tanning

According to U.S. researchers, the tumor suppressor gene p53 is not only involved in the regulation of cell proliferation. It would also contribute to the process of pigmentation of the skin exposed to UV and would have a role in addiction to tanning.
An important mechanism
The responsibility of the p53 gene is large: it is the guardian of the integrity of the genome of the cells. Once an anomaly appears at the DNA level, it stops momentarily the cell division cycle and activates repair mechanisms of the genome. At worst, it triggers apoptosis, cell suicide, to prevent irreparable damage are transmitted to subsequent generations.

Repairing or removing defective genomes, the p53 gene limits the development of cancer, which earned him the name of the tumor suppressor gene. The findings also revealed a protective role, since in case of attack by free cells, damaging DNA radicals, it activates genes encoding proteins capable of maintaining a protective antioxidant environment.

The potential of p53 expands again with the results of a study by David Fischer at Dana-Farber Cancer Institute in Boston, reported in the latest edition of the Bulletin of cancer. The researchers say that the cutaneous level, the gene also contributes to the formation of melanin, responsible for skin pigmentation when it is exposed to sunlight.

The value remains the same: to protect DNA, but this time against the harmful effects of ultraviolet light, causing the development of skin cancers.

Relief of inflammation
Keratinocytes, superficial skin cells, are more exposed to UV radiation. According to researchers, it is predominantly in the genome of these cells as the p53 gene is activated upon exposure to sunlight, then inducing, by means of another gene, the formation of a polypeptide, the proopiomelanocortin (POMC), the origin of the complex process of tanning.

To produce melanin which kératynocytes protect against the sun, melanocytes located in the lower layers of the skin, need to be stimulated by the hormone MSH (Melanocyt Stimulating Hormone) which comes precisely cutting proteolysis of POMC . It is also, as the authors point out, a failure in MSH receptor in people with fair skin which explains their difficulty tanning.

The relationship between P53 and tan extends even beyond the effect of MSH génoprotecteur since the two other molecules derived from the cleavage of POMC, the adrénocortocotrophique hormone (ACTH) and endorphin involved in relief of irritation and local inflammation of sunburn and skin too exposed to UV.

According to the researchers, the endorphin as antalgic natural, may even induce addiction to sun exposure and would therefore be responsible in the development of risk behaviors.