A protein that exists in milk can significantly reduce the rate at which colon cancer cells grow over time, researchers from the University of Lund, Sweden, reported in the Journal of Dairy Science, the official journal of the American Dairy Science Association.

Previous studies have shown that milk can reduce the risk of developing diabetes and metabolic syndrome. One study found that milk can also positively impact your brain and mental performance.

Professor Stina Oredsson and team found that Lfcin4-14 (lactoferricin4-14), a milk protein which researchers have known has several health benefits, considerably reduces the growth rate of colon cancer cells over the long term. The protein extends the cell cycle period before chromosomes are replicated.

The authors explained that treatment with lactoferricin4-14 reduced DNA damage in colon cancer cells caused by exposure to UV light.

Professor Oredsson said:

“We previously hypothesized that the prolongation of the cell cycle in colon cancer cells as a result of Lfcin4-14 treatment may give the cells extra time for DNA repair. Indeed, UV light-induced damage was decreased in colon cancer cells treated with Lfcin4-14 compared with controls. The differences were small but significant.”

The scientists first exposed the colon cancer cells to UV light, which damaged their DNA. They then grew the cells either with Lfcin4-14 present or without it.

DNA damage was assessed by using comet assay – a sensitive measuring technique. After being processed, the DNA-damaged cells look like a comet, with its characteristic tail. The ratio of the tail-intensity to the comet head indicates how extensive the DNA damage is. When exposed to UV light there were more comets. However, after being exposed to Lfcin4-14, the number of comets in the UV light-exposed cells went down.

The researchers wanted to find out which mechanism Lfcin4-14 used to reduce DNA damage. They evaluated the levels of a number of proteins involved in cell cycle progression, DNA repair, and cell death.

They found a rise in flap endonuclease-1, a protein linked to DNA synthesis; a drop in b-cell lymphoma 2-associated X protein, which plays an important role in cell death; and a fall in the level of -H2AX, suggesting improved DNA repair.

Dr. Oredsson said “These changes in expression support our hypothesis that Lfcin4-14 treatment resulted in increased DNA repair.”

Cancer cells typically have flaws in their DNA repair mechanisms, Dr. Oredsson explained.

Dr. Oredsson concluded:

“Our data suggest that the effects of Lfcin4-14 in prolonging the cell cycle may contribute to the cancer preventive effect of milk. This must be further investigated in different systems.”

Over one million people worldwide get colon cancer every year. Approximately half-a-million people die of the disease each year. Since 2008, colon cancer is the second most common cancer in adult females and the third most common in males. Colon cancer is much more common in industrialized nations.

US health authorities say that approximately 4.96% of US adults will be diagnosed with colorectal cancer at some time in their lives.

Written by Christian Nordqvist