Secondary bile acids: an underrecognized cause of colon cancer

Abstract

Bile acids were first proposed as carcinogens in 1939. Since then, accumulated evidence has linked exposure of cells of the gastrointestinal tract to repeated high physiologic levels of bile acids as an important risk factor for gastrointestinal cancers. High exposure to bile acids may occur in a number of settings, but most importantly, is prevalent among individuals who have a high dietary fat intake.A rapid effect on cells of high bile acid exposure is the generation of reactive oxygen species and reactive nitrogen species, disruption of the cell membrane and mitochondria, induction of DNA damage, mutation and apoptosis, and development of reduced apoptosis capability upon chronic exposure. Here, we review the substantial evidence of the mechanism of secondary bile acids and their role in colon cancer.

The Role of Soluble, Insoluble Fibers and Their Bioactive Compounds in Cancer: A Mini Review

“…A report on concentration of secondary fecal bile including 15 healthy individuals concluded that wheat and rye fiber (rich in cellulose) lead to low concentration in the fecal bile [46]. High bile acid concentration can also lead to colon cancer, it was considered in "carcinogens" in 1939, and the most dominant cause was fat intake, since it was prevalent among individuals who have a high dietary fat intake [47]. Evidence has been showed to prove the mechanism of secondary bile acids effect leading to colon cancer [47].…”

“…High bile acid concentration can also lead to colon cancer, it was considered in "carcinogens" in 1939, and the most dominant cause was fat intake, since it was prevalent among individuals who have a high dietary fat intake [47]. Evidence has been showed to prove the mechanism of secondary bile acids effect leading to colon cancer [47]. Their amphipathic nature enables them to get involved in emulsification and digestion of dietary fats; yet, levels above those that are physiologic are potentially membrane damaging [48].…”

Bile acids cycle disruption in patients with nasopharyngeal carcinoma promotes the elevation of interleukin-10 secretion

“…For example, the dysregulation of bile acids has close relationship with gastrointestinal cancer 8 . Secondary bile acids have been considered to be a cause of colon cancer 9 . The experiments performed by Liu et al showed that conjugated bile acids promoted cholangiocarcinoma cell invasive growth through the activation of sphingosine 1-phosphate receptor 2 10 .…”

Serum diagnostic glycoprotein biomarkers for Barrett's esophagus and esophageal adenocarcinoma

“…When Nehra and colleagues profiled esophageal aspirates in the patients suffering from erosive esophagitis and Barrett's esophagus and compared with that of healthy individuals, they found significantly increased proportion of secondary bile acids, deoxycholic acid and taurodeoxycholic acids to be present in patients with erosive esophagitis and BE (505). Bile acids (especially secondary bile acids) are known for their causative roles for many gastrointestinal cancers (506,507). At physiological levels repeated and prolonged exposure of bile acids in esophageal tissue, which is not meant to deal with gastric/bile acid, can cause oxidative/nitrosative stress, DNA damage leading to generation of genomic instability, apoptosis, and ultimately cancer (508,509).…”

“…Bile acids are physiological detergents and enable absorption of lipids, cholesterol, and fatsoluble vitamins from the gastrointestinal tract (507). Cholic acid and chenodeoxycholic acid are primary bile acids which are derived from cholesterol by a sequence of enzymatic reactions that involve 17 different enzymes and occur mainly in the liver (510).…”