Liver cancer growth tied to tryptophan intake

Medical Xpress / UT Southwestern Medical Center / Nature Communications ^ | Aug. 1, 2024 | Niranjan Venkateswaran et al

[ConservativeMind]

Researchers have discovered that a diet free of the amino acid tryptophan can effectively halt the growth of liver cancer in mice. Their findings offer new insights for dietary-based cancer treatments and highlight the critical role of the tryptophan metabolite indole 3-pyruvate (I3P) in liver tumor development.

Hepatocellular carcinoma (HCC) is the third-leading cause of cancer-related mortality worldwide, with limited options for effective treatment and a five-year survival rate of about 30%. The study shows that growth of liver cancers driven by the MYC oncogene is particularly dependent on tryptophan, which is converted into I3P as well as other metabolites.

By removing tryptophan from the diet of mice, researchers stopped the growth of MYC-driven liver tumors and restored normal gene expression in liver cells. Notably, this dietary intervention did not affect protein synthesis in normal cells, suggesting a targeted therapeutic approach that spares healthy tissues.

"Liver tumors require large amounts of tryptophan to generate the oncometabolite I3P," Dr. Conacci-Sorrell said. "A tryptophan-free diet prevents liver tumor growth by a mechanism that depends on I3P but is independent of translation, the process by which proteins are synthesized from amino acid building blocks. Because tryptophan is the amino acid with the lowest abundance in the proteome, short-term dietary manipulation is safe for healthy tissues but not for cancer cells."

Among foods high in tryptophan are turkey, red meat, pork, chicken, tofu, milk, soybeans (including edamame), quinoa, oats, and fish.

The research highlights the complex role of tryptophan metabolism in cancer. While tryptophan is known to be metabolized into several important compounds, including the neurotransmitter serotonin and kynurenine, a precursor of the B vitamin niacin, the study showed MYC-driven liver tumors preferentially utilize tryptophan to produce I3P rather than kynurenine. This shift underscores the potential for targeting specific metabolic pathways in cancer treatment.

[lee martell]

Good suggestions. I love passing a long day making soups, stews or what I call Michigan Gumbo, using smelts, if you can find them. Back in college, I was the only one of 3 roommates who liked cooking and eating beef liver.

[aimhigh]

A lot of cancer cures work in mice, that don’t work in humans. I’d want to know if this worked in humans before changing my diet.