A team of scientists has made a discovery that could lead to better treatments for aggressive forms of breast cancer. A devastating form of cancer called triple negative breast cancer can “starve” to death if deprived of cystine molecules. The findings could lead to the development of effective treatments for one of the deadliest types of breast cancer. The details are in a paper that was just published in the journal Oncogene.
Triple negative breast cancer (TNBC) is one of the most difficult forms of breast cancer to treat. TNBC doesn’t respond to typical treatments since the tumors lack the three receptors that are the usual therapeutic targets: the progesterone receptor, the estrogen receptor, and the Her2/neu receptor. Patients diagnosed with TNBC have few options and usually undergo chemotherapy or surgery. Up to 20% of new annual breast cancer cases are TNBC forms. An effective treatment for TNBC could save many lives each year.
Researchers from Duke University attempted to identify the chemicals and nutrients that TNBC tumor cells need to survive and proliferate. In one experiment, a team of scientists grew TNBC tumor cells but deprived each group of a specific amino acid. The only absent amino acid that led to cell death was cysteine. After further analysis, the team found that the tumor cells needed a molecule called cystine in order to survive. Cystine consists of two cysteine molecules linked together and the TNBC cells were using it to metastasize. Metastasis is the process that tumor cells use to spread to other parts of the body. In this case, TNBC cells required cystine to accomplish this type of movement. Depriving the cells of cysteine had the side effect of removing cystine molecules from the TNBC cells, starving them. In fact, this deprivation killed TNBC cells very quickly and prevented them from spreading.
A research team has finally pinpointed a possible target for treatment of aggressive TNBC. The team is already conducting further research to determine the best way to safely administer cystine-blocking molecules to tumor sites.
Tang et al. Cystine addiction of triple-negative breast cancer associated with EMT augmented death signaling. Oncogene (2016).