A research group led by Dr Rajesh Agarwal at the Colorado Cancer Center has identified silibinin, an extract from milk thistle, as a potential drug against UV-induced skin cancer.
UV radiation damages skin cells by causing lesions to be formed in the DNA; these can be noticed quickly and repaired by specific cellular mechanisms, or can accumulate to such a degree as to lead to cell death. Cancerous cells evade these death signals, and continue to grow, divide and build up mutations in their DNA – a condition that will often be fatal if left untreated.
Silibinin appears to protect the cells from UVB damage, as well as inducing cell death in those cells that have been damaged by UVA radiation. In the case of the former, the silibinin will induce the production of interleukin-12, a molecule that stimulates the repair machinery of these cells. With the latter, silibilin will increase the production of reactive oxygen intermediates, which (as their name suggests) will react detrimentally with various cellular components. The cell will eventually longer be able to sustain itself due to this damage, which inevitably results in cell death.
Dr Agarwal’s studies so far have shown the effectiveness of silibinin in both skin and solid cancers through studies on both cell cultures and mice. The group are now working towards starting therapeutic trials with sibilin-based drugs on human patients.
