Vitamin B7 Shows Promise as Potential Weakness in Cancer Cells

Research reveals a hidden metabolic vulnerability in some cancer cells linked to vitamin B7 (biotin), offering potential new avenues for treatment.

All living cells must adapt to changes in nutrient availability to survive. Though, cancer cells often exhibit a strong dependence on glutamine, an amino acid crucial for building proteins and DNA. This “glutamine addiction” has long been considered a potential weakness, but many tumors develop ways to circumvent this dependence. Now, a study published in the journal Molecular Cell reveals how some cancer cells bypass this need for glutamine and identifies vitamin B7 as a key factor in this process.

How Cancer Cells Bypass Glutamine Dependence

Researchers at the University of Lausanne (Unil) in Switzerland discovered that cancer cells can utilize carbon-rich molecules, specifically pyruvate, to continue dividing even when glutamine levels are low. This workaround relies on an enzyme called pyruvate carboxylase, found within mitochondria – the cell’s energy-producing structures.

Crucially, pyruvate carboxylase requires vitamin B7 (biotin) to function. Without biotin, the enzyme remains inactive, effectively halting cancer cell growth. Biotin acts as a “metabolic license,” enabling pyruvate to enter the energy-producing pathways and compensate for the lack of glutamine [1].

The Role of the FBXW7 Gene

The research also uncovered the involvement of the FBXW7 gene. Mutations in this gene can lead to a decrease in pyruvate carboxylase, rendering pyruvate ineffective and forcing cancer cells to rely on glutamine once again. Researchers confirmed this connection by observing cancer patients, finding that specific FBXW7 mutations correlate with metabolic dependence on glutamine [1].

Implications for Cancer Treatment

These findings highlight a previously unknown metabolic vulnerability in certain cancer cells. By understanding how these cells bypass their dependence on glutamine, researchers hope to develop innovative treatment strategies. Targeting vitamin B7 metabolism, or the FBXW7 gene, could potentially disrupt this workaround and make cancer cells more susceptible to existing therapies [2], [3].

Further Research and Findings

A study published in Cell by Lisci et al. Further supports these findings, presenting a unified model of how cells escape glutamine addiction. The research demonstrates that biotin and the tumor suppressor FBXW7 sustain mitochondrial pyruvate carboxylation, with FBXW7 acting upstream of MYC-mediated transcriptional regulation [4].

Key Takeaways

• Some cancer cells can bypass their dependence on glutamine by utilizing pyruvate.
• Vitamin B7 (biotin) is essential for the enzyme pyruvate carboxylase to function, enabling this bypass.
• Mutations in the FBXW7 gene can disrupt this process, making cancer cells reliant on glutamine.
• These findings offer potential new targets for cancer treatment.