A team of researchers has found that a natural carotenoid pigment called beta-cryptoxanthin reduces tumor growth in mice suffering from nicotine-triggered lung cancer. Fresh foods, including peppers and citrus fruits, are rich in the compound. The findings may help smokers prevent or treat lung cancer in the early stages. The details are in a paper that was published in the journal Cancer Prevention Research.
Beta-cryptoxanthin (BCX) is a naturally-occurring carotenoid found in a variety of fresh fruits and vegetables. The pigment is primarily found in yellow, red, and orange foods such as oranges, squash, red bell peppers, and papaya. It’s found in some animal products, including eggs, but fruits and vegetables contain the highest concentrations. Previous studies had linked BCX to a reduced risk of nicotine-linked lung cancer but the actual mechanisms were unknown.
Researchers from the USDA’s Nutrition and Cancer Biology Laboratory studied the effects of BCX on laboratory mice. The team used mice that are especially prone to developing lung cancer tumors after exposure to a nicotine-based carcinogen called NNK. NNK is found in most tobacco products as well as many e-liquids that are designed for use in vapes and electronic cigarettes.
The mice were given a high dose of NNK to trigger tumor development. Some groups were fed BCX in their daily diets while others received low doses or no BCX at all. The animals were given realistic amounts of the carotenoid, the equivalent of a human eating a cup of fresh vegetables or fruits.
After 16 weeks, the scientists found that mice that had consumed BCX developed less tumors—a 52 to 63% reduction on average. The research team also conducted a separate experiment with human lung cancer cells and found that BCX treatment reduced the invasiveness of the tumor cells. BCX inhibited the activity of alpha7 nicotine receptors, which have already been linked to the growth and migration of cells. The team concluded that BCX may work as a preventative or early treatment for nicotine-triggered lung cancer.
The authors believe that BCX is a promising lung cancer preventative but caution that more studies, with human models, are needed.
Iskandar et al. β-Cryptoxanthin Reduced Lung Tumor Multiplicity and Inhibited Lung Cancer Cell Motility by Downregulating Nicotinic Acetylcholine Receptor α7 Signaling. Cancer Prevention Research (2016).