Glycogen Stores in Cancer Cells and Breast Cancer Metastasis

Introduction to Glycogen and Hypoxia in Tumors

High energy stores of glycogen found in cancer cells may contribute to the aggressive spread of breast cancer. Over fifty percent of solid tumors exhibit areas of hypoxia, which refers to regions with inadequate oxygen supply. This hypoxic condition is associated with metastasis, or the spread of cancer, and is linked to poorer outcomes in various cancer types, including breast cancer. Research indicates that hypoxic environments are closely tied to breast cancer progression and patient mortality.

The Role of Glycogen in Cancer Cell Survival

When cells experience oxygen deprivation, they activate specific cell signaling pathways to adapt. One significant response is the accumulation of glycogen, a primary energy-storing molecule. This glycogen serves as an energy source that facilitates the spread of breast cancer. Elevated glycogen levels have been observed in cancer cells and within the cores of hypoxic tumors in numerous cancers.

Research Findings on Glycogen and Cancer Metastasis

A recent study published in PLOS ONE by a team of researchers from the United States explored the relationship between glycogen stores in cancer and their influence on tumor invasion and dissemination. The researchers initially measured glycogen levels in different breast cancer cell types. They found that breast cancer cells can store significant energy, nearly equivalent to that of the liver, the primary organ for glycogen storage. This capability allows cancer cells to break down glycogen into energy, supporting their growth and spread.

Impact of Enzyme Inactivation on Glycogen Metabolism

The study also examined how glycogen energy stores and metabolism are affected by inactivating a protein enzyme known as PYG, which is crucial for glucose metabolism. The inactivation of this enzyme led to a reduced ability of cancer cells to break down glycogen for energy, subsequently diminishing the cancer’s capacity to proliferate and spread. This reduction in glycogen utilization resulted in less aggressive cancer behavior.

Implications for Future Research and Treatment

These significant findings should inform and direct future research into glucose metabolism not only in breast cancer but also in other malignancies. The research team aims to leverage these insights to explore the potential for developing new treatments targeting the PYG enzyme to treat or prevent breast cancer metastasis, with further studies planned in animal models.

Conclusion

Overall, the study underscores the importance of glycogen metabolism in the aggressiveness of breast cancer, highlighting a promising avenue for therapeutic intervention.

References

Altemus, M. A., Goo, L. E., Little, A. C., Yates, J. A., Cheriyan, H. G., Wu, Z. F., & Merajver, S. D. (2019). Breast cancers utilize hypoxic glycogen stores via PYGB, the brain isoform of glycogen phosphorylase, to promote metastatic phenotypes. Plos One, 14(9). doi: 10.1371/journal.pone.0220973

Study: Aggressive breast cancers store large amounts of energy, which enables it to spread. (2019, October 4). Retrieved from https://www.eurekalert.org/pub_releases/2019-10/mm-u-sab100419.php

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