A recent study at Sweden’s Karolinska Institute has revealed that a protein called GIT1 has shown the ability to protect against the growth of estrogen receptor-negative breast tumors. This type of breast cancer is among the most difficult variations to treat, and the researchers behind this study have found evidence that the protein could lead to better prognoses for breast cancer patients. Additionally, the findings of this study have sparked optimism that GIT1 could be used to develop innovative treatment methods for treatment-resistant forms of breast cancer.
Breast cancer is one of the most common types of cancer, with a devastating impact on a personal, medical, and societal level. According to the American Cancer Society, breast cancer accounts for about 30% of all new female cancers each year in the United States. Additionally, the ACS estimates that about 13% of all American women will be diagnosed with breast cancer sometime in their lives.
While these statistics are bleak, the hard work of cancer researchers has provided hope that breast cancer outcomes could improve as new discoveries are made. The new Swedish discovery and other ongoing studies could potentially lead to the development of groundbreaking treatment methods that could significantly improve survival rates.
The Role of Estrogen Receptors in Breast Cancer
The different types of breast cancer are categorized based on whether or not the estrogen receptor is present. Hormonal therapies have shown relatively successful results in the treatment of ER-positive breast cancers, but ER-negative variations have responded to fewer forms of treatment. Triple-negative breast cancers, which lack not only the estrogen receptor but also the progesterone and HER2 receptors, are especially difficult to treat.
Here is a quick overview of the three main types of hormone status in breast cancers:
- ● Estrogen receptor (ER) positive – In ER-positive breast cancers, the cancer cells contain receptors that encourage growth through the use of estrogen. Oncologists often use anti-estrogen hormone (endocrine) therapy to block cancer cell growth for ER-positive patients.
- ● Progesterone receptor (PR) positive – PR-positive breast cancers are sensitive to progesterone. Cells in these types of cancers also contain receptors that allow the cells to use progesterone to stimulate growth. Endocrine therapy is also used to block cancer cell growth in PR-positive breast cancers.
- ● Hormone receptor (HR) negative – This category of breast cancer does not contain any hormone receptors. Thus, it will not respond to endocrine treatments that are designed to block hormones.
Notch Signaling and Cancer
The Notch signaling pathway is related to the proliferation, differentiation, and survival of cells. This pathway is often activated in cancer patients and can make it easier for cancer to spread, or metastasize. Previous research has discovered that inhibiting the Notch pathway could be an effective method for improving treatment options and outcomes for patients with chemo-resistant types of cancer.
The recent Karolinska Institute study, which was published in the journal Nature Communications, has shown that high levels of the GIT1 protein can effectively act as Notch signaling inhibitors. This inhibiting effect could be used to protect against further tumor growth in patients with the more difficult-to-treat forms of breast cancer.
Past research has shown a correlation between overactive Notch signaling and worse prognoses in breast cancer patients. There is hope that the discovery of a new mechanism in this study could lead to more effective treatment methods for breast cancer patients who exhibit hyperactivity in the Notch pathway.
GIT1 Protein Expression in Breast Cancer Patients
According to the findings of the Karolinska Institute study, patients who exhibit high levels of GIT1 have a better prognosis than those who show lower levels. The researchers found a novel mechanism in which the GIT1 protein regulates the Notch signaling pathway, which can impact the initiative and growth of ER-negative breast cancers.
This study analyzed the tumor cells from breast cancer patients, showing that high GIT1 levels inhibited Notch signaling and helped to stop tumor growth. Conversely, low levels of GIT1 were associated with more severe tumor growth. In addition, the ER-negative breast tumors showed lower GIT1 levels than the ER-positive tumors.
Potential Future Therapies Using GIT1
Led by Professor Per Uhlén, the team of researchers at the Karolinska Institute plans to build off these findings by working towards developing innovative cancer treatment therapies based on the results of the study.
Uhlén has announced that the researchers are hoping to conduct additional research that could be used to help patients with severe diseases. He has noted that the Karolinska Institute has premium-quality tools and equipment that can be used to develop promising new therapies. The research from this study was conducted at the Karolinska Institute and was funded by the Swedish Research Council, the Swedish Cancer Society, the Wallenberg Academy Fellow grant from the Knut and Alice Wallenberg Foundation, among other funding sources.