A revolutionary new breast cancer treatment has been shown to eliminate small breast tumors and significantly shrink larger ones in mice with a single dose.
This innovative approach more selectively targets estrogen receptor-positive cancers, with the goal of reducing side effects and improving patient outcomes.
New research on breast cancer treatment
Despite therapeutic advances, breast cancer remains one of the leading causes of cancer death among women. Standard treatment usually includes surgery followed by hormone therapy. However, these treatments can have long-term side effects, such as osteoporosis, sexual dysfunction, and blood clots. The researchers publish today (January 22) in ACS Central Science have now developed a new treatment that, in a single dose, eliminates small breast tumors and significantly shrinks larger ones in mice, all without harmful side effects.
Current Limitations of Hormone Therapy
The majority of breast cancers are estrogen receptor positive (ER+), meaning they rely on estrogen to grow. Current treatment often requires several years of hormonal therapy, which, although generally more tolerable than chemotherapy, can nevertheless result in significant side effects impacting quality of life. In addition, these treatments do not eliminate the risk of cancer recurrence or resistance. This highlights the urgent need for therapies that can effectively target and destroy cancer cells while minimizing adverse effects.
Development of a promising molecule
To address this challenge, Paul Hergenrother and his colleagues previously developed a small molecule called ErSO. This compound kills ER+ breast cancer cells but causes unwanted side effects. In 2022, researchers synthesized a series of small molecules similar to ErSO. This previous study demonstrated that these derivatives have higher potency, greater selectivity for ER+ cancer cells, and better pharmacological properties than the parent compound.
Breakthrough results with ErSO-TFPy
In the latest study, researchers further evaluated one derivative, ErSO-TFPy, and found that it:
- Effectively kills multiple ER+ human breast cancer cell lines in culture.
- Was well tolerated, without obvious deleterious effects, by several
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- Reduces transplanted human breast tumors of various genetic backgrounds in mice.
Potential for transformative cancer treatment
In a dosing experiment, the researchers noted that a single dose of ErSO-TFPy in mice induced complete or near complete regression of small or large tumors that had developed in the animals, respectively. Other medications require long-term dosing, but researchers suggest that a single dose of ErSO-TFPy and therefore minimal circulation in the body could help reduce the risk of side effects and late effects. They acknowledge the need for more testing to confirm the safety and effectiveness of the drugs, but suggest that if these results translate to human patients, ErSO-TFPy could be transformative for the treatment of ER+ breast cancer .
“It is very rare for a compound to shrink tumors in mouse models of breast cancer, let alone completely eradicate these tumors with a single dose. So we look forward to seeing ErSO-TFPy advance in the treatment of breast cancer “, says Hergenrother.
Reference: “A single dose of a small molecule leads to complete regressions of large breast tumors in mice” January 22, 2025, ACS Central Science.
DOI: 10.1021/acscentsci.4c01628
The authors acknowledge funding from the National Cancer Institute to
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