Chemoprevention with phytonutrients and microalgae products in chronic inflammation and colon cancer

Inflammatory bowel disease (IBD) is a chronic inflammatory disorder caused by deregulated immune responses in a genetically predisposed individual. This is a complex process mediated by cytokines, chemokines, adhesion molecules, cytoplasm nuclear receptors, among others. Recent data support a participation of the endoplasmic reticulum (ER) stress and mitochondrial dysfunctions in IBD. Moreover, now it is evident that chronic degenerative pathologies, including IBD, share comparable disease mechanisms at the cellular level with alteration of the autophagy mechanisms. Mounting evidence suggests that the risk of developing colorectal cancer (CRC) is dramatically increased in patients with chronic inflammatory disease. Chronic inflammation in IBD exposes these patients to a number of signals known to have tumorigenic effects including nuclear factor kappa B (NF-κB) activation, proinflammatory cytokines and prostaglandins release and reactive oxygen species (ROS) production. Chemoprevention consists in the use of drugs, vitamins, or nutritional supplements to reduce the risk of developing, or having a recurrence of cancer. Numerous in vitro and animal studies have established the potential colon cancer chemopreventive properties of phytochemicals derived from both plants (curcumin, resveratrol, epigallocatechin gallate, quercetin or genistein) and substances from marine environment, including microalgae species and their products. This review summarizes the mechanisms by which these naturally occurring compounds may mediate chemopreventive effects on cancer. These actions include induction of cell cycle arrest and apoptosis, inhibition of cell proliferation, stimulation of antimetastatic and antiangiogenic responses and increased antioxidant and anti-inflammatory activity.