We should have listened to our mothers, always telling us to wear sunscreen. That’s because skin cancer is the most common form of cancer in the United States and, due to its ability to metastasize quickly, melanoma is the most dangerous type.

But you’re in luck. An article published this week in PNAS demonstrates a potential new target for preventing the spread of melanoma. Based on previous work, which showed that microRNAs (miRNAs), small endogenous noncoding RNAs that regulate gene expression, exhibited DNA copy number alterations in a variety of cancers, a group at NYU Medical Center decided to investigate the role of miRNAs in the spread of melanoma. Using quantitative RT-PCR and in situ hybridization of tissue microarrays, researchers found that expression of miRNA-182 (miR-182) is upregulated in melanomas. When expression of miR-182 was knocked down, the invasive behavior of melanoma cells was diminished and the cells began to die. Conversely, increased expression of miR-182 improved the metastatic behavior of the cells in vitro and in vivo.

Using public databases for potential target genes, the researchers went on to characterize the targets of miR-182, which might promote the progression of melanoma by improving the invasive behavior of the cells. Two targets identified were microphthalmia-assocaited transcription factor (MITF) and forkhead box O3 (FOXO3) transcription factor, whose expression was suppressed by miR-182. Previously, FOXO3 had been shown to mediate cell death, which suggests that miR-182 inhibits expression of FOXO3 and MITF, promoting cell survival and metastasis. Perhaps, in the future, miRNA therapies aimed at miR-182 and its targets could be used in the treatment of melanoma and other forms of cancer.

But for now, listen to your mother, wear your sunscreen, and avoid a cancerous situation all together.

M. F. Segura, D. Hanniford, S. Menendez, L. Reavie, X. Zou, S. Alvarez-Diaz, J. Zakrzewski, E. Blochin, A. Rose, D. Bogunovic, D. Polsky, J. Wei, P. Lee, I. Belitskaya-Levy, N. Bhardwaj, I. Osman, E. Hernando (2009). Aberrant miR-182 expression promotes melanoma metastasis by repressing FOXO3 and microphthalmia-associated transcription factor Proceedings of the National Academy of Sciences, 106 (6), 1814-1819 DOI: 10.1073/pnas.0808263106