Animal Lipids Linked to Inflammation and Cancer

Lisa Franchi November 05, 2014

Researchers from Children’s Hospital Oakland Research Institute found that lipids found in mammalian food products and generated by normal human cells can contribute to inflammation of the colon, inflammatory bowel disease (IBD) and inflammation-associated colon cancer, whereas soy and plant-type lipids may protect against these conditions.

For decades, scientists have linked inflammation with cancer. Such link is particularly evident in colon carcinogenesis, because patients with IBD have a higher incidence of colon cancer than the general population. Evidence suggests that inflammation contributes to the earliest stages of carcinogenesis, namely in the process of cell transformation, where the cell acquires many aspects of cancer characteristics. The observation that IBD and colon cancer incidence rise as nations industrialise suggests that changes in diet and nutrition contribute to colitis and colitis-associated colon cancer.

In the current study, researchers found that mice with higher levels of sphingosine-1-phosphate (S1P) had more inflammation and a higher incidence of tumours on this regimen. Using a combination of mouse and cell culture experiments, the scientists identified a cascade of steps downstream of S1P that lead eventually to the silencing of two tumour suppressing proteins whose functions are to protect against the formation of cancer.

On the other hand, the soy or plant-type sphingolipids called sphingadienes cannot be metabolised to S1P and instead enhance the metabolism of S1P by increasing SPL levels in gut tissues when fed to mice. Further, sphingadiene treatment of mice reduced inflammation, signs of IBD, and the incidence of tumours. Finally, the researchers showed an increase in S1P-related gene expression in the colons of patients with IBD compared to controls.

According to the researchers, this suggests that while mammalian sphingolipids may promote inflammation and carcinogenesis, plant/soy sphingolipids cannot be converted into S1P, are anti-inflammatory and reduce the activity of several cancer signalling pathways. The data suggests that dietary sphingolipids may enhance or inhibit colon carcinogenesis, depending on their ability to be metabolised to S1P.

The study was published online in the Journal of Clinical Investigation.

Source of this article: Sphingosine-1-phosphate lyase downregulation promotes colon carcinogenesis through STAT3-activated microRNAs