Excessive Intake of This Amino Acid Promotes Tumor Growth

• Facebook
• Twitter
• Reddit
• Tumblr
• LinkedIn
• Pinterest
• RSS Feed
• Link

Excessive Intake of This Amino Acid Promotes Tumor Growth; Limiting Intake Can Inhibit Tumor Growth Without Affecting Normal Cells

• Shocking! All existing AIDS vaccine developments have failed 
• Sanofi Japan Data Breach: 730000 Healthcare Professionals’ Information Exposed
• CT Radiation Exposure Linked to Blood Cancer in Children and Adolescents
• FDA has mandated a top-level black box warning for all marketed CAR-T therapies
• Can people with high blood pressure eat peanuts?
• What is the difference between dopamine and dobutamine?
• How long can the patient live after heart stent surgery?

Excessive Intake of This Amino Acid Promotes Tumor Growth; Limiting Intake Can Inhibit Tumor Growth Without Affecting Normal Cells

Tryptophan, an essential amino acid required by the human body, plays multiple important roles including protein synthesis, and the production of various bioactive substances such as serotonin and melatonin. It is commonly found in foods like beef, lamb, chicken, turkey, and milk.

Liver cancer is one of the most common malignant tumors and the third leading cause of cancer-related deaths worldwide, with a five-year survival rate of only 30%. China has the highest incidence of liver cancer globally.

Different types of cancers vary in their metabolic activities, preferred energy sources, and nutritional dependencies. Therefore, dietary interventions can selectively disrupt cancer cells while minimizing impact on healthy tissues.

Recently, researchers from the University of Texas Southwestern Medical Center published a study in the journal “Nature Communications” titled “Tryptophan fuels MYC-dependent liver tumorigenesis through indole 3-pyruvate synthesis.”

The study showed that restricting tryptophan intake can prevent MYC-driven liver cancer growth and restore normal gene expression in liver cells without affecting the protein synthesis of normal cells.

Additionally, the study found that the tryptophan metabolite indole-3-pyruvate (I3P) plays a crucial role in liver cancer growth. Supplementing I3P can restore the growth of liver cancer cells lacking tryptophan, indicating that targeting I3P is a potential therapeutic approach that does not harm healthy tissues.

The oncogene MYC is abnormally activated in liver cancer patients and is associated with poor prognosis. In mice, MYC is one of the most potent drivers of liver cancer. Previous studies have shown that MYC-driven liver cancer growth is particularly dependent on tryptophan, promoting the growth of cancer cells in vitro.

In this study, researchers compared normal liver tissues with MYC-driven liver tumors and found increased levels of tryptophan and its transport proteins in tumors, without a corresponding increase in tryptophan-metabolizing enzymes. The elevated tryptophan transport protein levels were induced by MYC.

Further analysis using carbon isotope-labeled tryptophan in MYC-driven liver cancer mice showed that MYC-driven liver cancers exhibited increased tryptophan uptake.

Next, researchers divided mice overexpressing MYC into three groups: control, low-tryptophan, and tryptophan-free diets, and fed them for 21 days to analyze the importance of tryptophan in MYC-driven liver cancer.

The results showed that a tryptophan-free diet prevented MYC-driven liver cancer growth, restored normal gene expression in liver cells, and reduced tumor burden, although the tumors did not disappear, indicating that short-term tryptophan restriction can inhibit tumor growth.

Notably, the tryptophan-free diet did not affect the protein synthesis of normal cells, suggesting this is a targeted treatment method that does not harm healthy tissues.

Moreover, researchers analyzed the effect of tryptophan metabolites on tumor growth and found that in MYC-driven liver cancer, the levels of the tryptophan metabolite I3P were higher than those of tryptophan itself. Supplementing I3P could restore the growth of tryptophan-deficient liver cancer cells, highlighting I3P’s crucial role in liver cancer growth.

Researchers noted that liver tumors require large amounts of tryptophan to produce the carcinogenic metabolite I3P. Since tryptophan is the least abundant amino acid in the proteome, short-term restriction is safe for healthy tissues but significantly impacts cancer cells.

This study underscores the complex role of tryptophan metabolism in cancer and suggests that MYC-driven liver tumors preferentially utilize tryptophan to produce I3P. This highlights the potential of targeting specific metabolic pathways in cancer treatment and suggests that targeting I3P or its production pathways may be a viable therapeutic strategy.

In summary, the results indicate that limiting tryptophan intake can prevent MYC-driven liver cancer growth without affecting the protein synthesis of normal cells. Future research is needed to determine the long-term effects and safety of tryptophan restriction on tumors.

For more details, you can read the full paper at: https://doi.org/10.1038/s41467-024-47868-3

Excessive Intake of This Amino Acid Promotes Tumor Growth; Limiting Intake Can Inhibit Tumor Growth Without Affecting Normal Cells

(source:internet, reference only)

Disclaimer of medicaltrend.org

Important Note: The information provided is for informational purposes only and should not be considered as medical advice.