scientists, including an Indian-American researcher, have identified a molecule that can help treat breast cancer, giving hope to patients who have become resistant to traditional therapies. A first-in-class molecule shuts down estrogen-sensitive breast cancer in a new way, researchers report. First-class drugs are those that work by a unique mechanism—in this case, a molecule that targets a protein on the estrogen receptor of tumor cells.
A potential drug offers hope for patients whose breast cancer has become resistant to traditional therapies.” This is a fundamentally different, new class of agents for estrogen receptor-positive breast cancer,” said Ganesh Raj, a professor at the University of Texas Southwestern (UT Southwestern) Simmons Cancer Center.”Its unique mechanism of action overcomes the limitations of current therapies,” said Raj.
All breast cancers are tested to see if they need estrogen to grow, and about 80 percent are found to be sensitive to estrogen, the researchers said. These cancers can often be effectively treated with hormone therapy such as tamoxifen, but up to a third of these cancers eventually become resistant, they said. The new compound is a potentially highly effective next-line treatment for these patients, Raj said.
Traditional hormone drugs such as tamoxifen work by binding to a molecule called the estrogen receptor on cancer cells, preventing estrogen from binding to the receptor, a necessary step for cancer cells to multiply. However, the estrogen receptor can mutate and change shape over time, so that the treatment drug no longer fits the receptor exactly. When this happens, the cancer cells begin to multiply again. There is intense interest in developing drugs that block the ability of the estrogen receptor a major target in most breast cancers to interact with coregulatory proteins that drive tumor growth,” said David Mangelsdorf, a professor at UT Southwestern.“ Blocking such ‘protein-protein interactions’ has been a dream of cancer researchers for decades.
The drug works by blocking other molecules – proteins called cofactors – that also need to attach to the estrogen receptor for cancer cells to multiply. The new molecule, called ERX-11, mimics a peptide or protein building block.
