Scientists, including an Indian-American researcher, have identified a molecule that may help treat breast cancer, bringing hope to patients who have become resistant to traditional therapies.
The first-in-its-class molecule shuts down estrogen-sensitive breast cancer in a new way, the researchers said.
The first drugs of this type are those that work through a single mechanism; in this case, a molecule that targets a protein on the tumor cell’s estrogen receptor.
The potential drug offers hope to 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.
All breast cancers are tested to determine if they require estrogen to grow, and about 80 percent are found to be estrogen-sensitive, the researchers said.
These cancers can often be treated effectively with hormonal 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 hormonal medications, 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 its shape over time, so the treatment drug no longer perfectly matches the receptor. When this happens, the cancer cells begin to multiply again.
There has been a lot of interest in developing drugs that block the ability of the estrogen receptor, the primary target in most breast cancers, to interact with coregulatory proteins that cause a tumor to grow, David Mangelsdorf said. , professor at UT Southwestern.
Preventing these “protein-protein interactions” has been the goal of cancer researchers for many years.
The drug works by blocking other molecules, proteins called cofactors, that must also bind to the estrogen receptor for cancer cells to multiply.
The new molecule, called ERX-11, mimics a peptide or protein building block.