Differences in Breast Cancer Cell Metabolism

            Breast cancer is a disease that affects 1 in 8 American women. In 2017, around 250,000 women will be diagnosed with breast cancer, and almost 41,000 of those women will die from the cancer (American Cancer Society, 2017). For those patients who die from breast cancer, the primary reason is because the cancer metastasized. Thus, trying to find therapies that prevent cancer from metastasizing is crucial. Health Minute (2017) reports on a new study that was published in Nature Communications discussing how breast cancer that metastasizes utilizes a different nutrient metabolism than non-metastasizing cancer cells. This is exciting because identifying the pathways by which the cancer cells metastasize can lead to therapies that prevent metastasis from occurring.  

            More specifically, the researchers identified proline as an important component of energy production. Elia et al. (2017) utilized 2D and 3D conditions, meaning that some breast cancer cells were grown in spheroids while others were grown as a monolayer. Cells in the 3D condition utilized protein catabolism more often than 2D cells using the enzyme proline dehydrogenase (Prodh). When Prodh was inhibited, there was less breast cancer metastasis in vitro. Prodh is important because it has been show to contribute electrons into the electron transport chain, helping to generate ATP. So it would make sense that cells that want to travel to different parts of the body would utilize an enzyme that helps produce more energy. However, the researchers note that the role of Prodh is more pronounced in early metastasis rather than in secondary tumors. Although this research found that proline catabolism is what drives metastasis, the researchers note that proline biosynthesis also seems to affect how the cancer cells progress. Thus, it is evident that more research needs to be done on proline metabolism and its role in cancer cells. Nonetheless, the authors believe that there research show lead to new therapies targeting Prodh.  

           Although this is promising research, it is clear that we do not have a full understanding of how proline metabolism works. If a compound were identified that could inhibit Prodh, it leads to the question of whether or not it is ethical to begin recommending clinical trials even though there is not a clear understanding of proline metabolism in cancer cells? Although these researchers have good intentions with wanting to find more therapies, would it do more harm than good for the patient? 

References:

American Cancer Society. (2017). How Common Is Breast Cancer? Retrieved December 03, 2017, from https://www.cancer.org/cancer/breast-cancer/about/how-common-is-breast-cancer.html

Elia, I., Broekaert, D., Christen, S., Boon, R., Radaelli, E., Orth, M. F., . . . Fendt, S. (2017). Proline metabolism supports metastasis formation and could be inhibited to selectively target metastasizing cancer cells. Nature Communications,8, 15267. doi:10.1038/ncomms15267

Health Minute. (2017). Nutrient metabolism that drives breast tumor metastasis. Health Minute . Retrieved from https://healthminute.org/2017/11/nutrient-metabolism-that-drives-breast-tumor-metastasis/