Scientists identify potential breast cancer drug

New Delhi: In a major breakthrough, scientists have identified a molecule that can help treat breast cancer. This is a major step and gives hope to millions of patients worldwide who do not respond to traditional therapies.

It is said that breast cancer can be treated with hormone therapy such as tamoxifen but these cancers eventually become resistant. The identification of a molecule is being seen as a huge leap in treating cancer. Ganesh Raj, professor at the University of Texas Southwestern (UT Southwestern) Simmons Cancer Center says, “”Its unique mechanism of action overcomes the limitations of current therapies.”

The first-in-class molecule shuts down oestrogen-sensitive breast cancer in a new way, researchers said.

First-in-class drugs are those that work by a unique mechanism – in this case a molecule that targets a protein on the oestrogen receptor of tumour cells.

All breast cancers are tested to determine if they require oestrogen to grow and about 80 per cent are found to be oestrogen-sensitive, researchers said.

The new compound is a potential highly effective, next-line treatment for these patients, said Raj.

Traditional hormonal drugs, such as tamoxifen, work by attaching to a molecule called the oestrogen receptor in cancer cells, preventing oestrogen from binding to the receptor, a necessary step for cancer cells to multiply.

However, the oestrogen receptor can mutate and change its shape over time so that the treatment drug no longer fits neatly with the receptor. When this happens, the cancer cells start multiplying again.

“There has been intense interest in developing drugs that block the ability of the oestrogen receptor – the prime target in most breast cancers – from interacting with the co-regulator proteins that cause a tumour’s growth,” said David Mangelsdorf, 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 co-factors – that also must attach to the oestrogen receptor for cancer cells to multiply.

The new molecule, dubbed ERX-11, mimics a peptide, or protein building block.