Scientists have discovered the exact relationship between sugar and cancer by revealing that the way in which cancer cells break down sugar is linked to the stimulation of tumor growth.
Cancer cells tend to produce energy differently from normal cells – they use a process that involves fermentation of glucose into lactate, rather than ordinary respiration.
Every cell in the body needs sugar to survive. But cancer cells seem to require more than healthy cells do. They also seem to break sugar down faster. Cancer’s mechanism of speedily metabolizing sugar is known as the Warburg effect.
Scientists have long pondered whether this phenomenon is related to how aggressively tumors grow.
"Our research reveals how the hyperactive sugar consumption of cancerous cells leads to a vicious cycle of continued stimulation of cancer development and growth,” explained study author Professor Johan Thevelein, from Belgium’s VIB-KU Leuven Center for Cancer Biology, in a statement.
“Thus, it is able to explain the correlation between the strength of the Warburg effect and tumor aggressiveness. This link between sugar and cancer has sweeping consequences. Our results provide a foundation for future research in this domain, which can now be performed with a much more precise and relevant focus."
Before now it wasn’t clear whether the Warburg effect was just a symptom of cancer, or whether it could affect tumor growth. The new study shows that the Warburg effect actually stimulates the growth of cancerous tumors – although this in no way means that sugar causes cancer. The findings are published in the journal Nature Communications.
To conduct their research, the scientists used yeast as a model organism. Yeast also produces energy from sugar via fermentation, just like cancer cells do. It also contains the “Ras” proteins that are found in cancer.
One of the roles of Ras proteins in our bodies is to control cell growth. If the genes that control them mutate, Ras proteins can become permanently active, causing too much cell growth and hence the uncontrolled proliferation of cancer cells.
So, using yeast, the researchers looked at the relationship between Ras and high sugar metabolism.
"The main advantage of using yeast was that our research was not affected by the additional regulatory mechanisms of mammalian cells, which conceal crucial underlying processes. We were thus able to target this process in yeast cells and confirm its presence in mammalian cells,” explained Professor Thevelein.
These findings are very exciting in terms of the future of cancer research, as we know more about cancer’s relationship with sugar, but a breakthrough in research does not necessarily equal a breakthrough in medicine.
Whether increased sugar intake enhances cancer growth, or whether cancer’s sugar breakdown system could be interrupted, are still questions that remain unanswered.