New research in cell cultures and mice reveals a surprising link between the essential amino acid leucine and resistance to tamoxifen in breast cancer.
Scientists from Harvard Medical School, in Boston, MA, recently made this “unexpected” discovery about estrogen receptor-positive (ER-positive) breast cancer in a study conducted with colleagues from other research centers.
In laboratory experiments, they also found that the cell surface protein SLC7A5, which helps cells to take in leucine, influences the response of ER-positive breast cancer cells to tamoxifen.
The study authors note, in a paper published in Nature, that “SLC7A5 was necessary and sufficient to confer resistance to tamoxifen treatment” and suggest that the protein could be a potential target for “overcoming resistance” to tamoxifen in ER-positive breast cancer.
In around three-quarters of breast cancers, the hormone estrogen helps the tumors grow and spread.
This is because the cancer cells, like healthy breast cells, have estrogen receptors that allow them to receive growth signals from the hormone.
Doctors commonly treat ER-positive breast cancer with the drug tamoxifen because it blocks the action of estrogen in the cancer cells.
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