This 2-drug combo can shrink breast cancer tumors

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In a new study from McGill University, researchers found a new combination drug therapy that efficiently reduces tumor growth in metastatic breast cancer.

Their findings could lead to the development of a new first-line targeted therapy for the treatment of triple-negative breast cancer (TNBC).

Breast cancer is the leading cause of cancer death in women around the world, responsible for 1,700 deaths every day.

Although the vast majority of breast cancers are treatable, the most aggressive subtype—TNBC—has a high recurrence rate, a high potential for metastasis, and shows resistance to conventional treatments, leading to poor prognosis and survival outcomes.

While most breast cancers have one of three main receptors that are like entrance gates for treatments—estrogen, progesterone, and a protein called human epidermal growth factor (HER2)—TNBC has none, thus the name triple-negative breast cancer.

In the first part of the study, researchers identified about 150 genes that could either induce tumor formation (oncogenes) or prevent tumor formation (tumor suppressors).

The team then showed that in TNBC an oncogenic pathway (MTOR) is activated whereas a tumor suppressor pathway (HIPPO) is inhibited, which could possibly explain why those tumors are so aggressive and deadly.

To establish the therapeutic relevance of their findings, the team took the investigation one step further.

The researchers looked at existing drugs that could target these pathways and made experiments in vitro and in vivo.

As a result, they found two efficient drugs: Torin1, a second-generation drug known to block the MTOR pathway, and verteporfin, a drug normally used for a retina eye disease that can mimic the HIPPO pathway.

They mixed the two drugs together and used mathematical models and a pharmacological approach to define whether the two drugs were acting independently or in synergy.

They found the two drugs acted in a synergistic manner and efficiently reduced tumor growth in cell- and patient-derived xenograft models of TNBC.

The results of this study define a new approach to efficiently prevent tumor formation and reduce the tumor burden, i.e., the size of a tumor, or the amount of cancer in the body.

The proposed targeted combination therapy for TNBC patients will help fill an important medical gap in the metastatic breast cancer field.

If you care about breast cancer, please read studies about a new warning sign for breast cancer and findings of a major cause of deadly breast cancer.

The study is published in Nature Communications. One author of the study is Jean-Jacques Lebrun.

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