Tacrolimus Inhibits Breast Cancer Growth in Preclinical Trial
Tacrolimus, a transplant anti-rejection drug, inhibited breast cancer growth by more than 70 percent in a recent preclinical trial. This finding opens the door for a clinical trial in humans with breast cancer.
Breast tumor growth may be blocked
Tacrolimus is an immunosuppressant that works by reducing the activity of the immune system so the body will not attack the transplanted organ. To achieve this, it binds to and deactivates calcineurin, a protein found in immune cells.
Calcineurin is a factor that the immune system and cancer share, in that it stimulates the former and promotes the growth of new blood vessels to tumors in the latter. Tumors need a reliable blood supply to grow and survive; block it and the tumor stops growing.
Another factor is a protein called SFRP2. Nancy Klauber-DeMore, MD, associate professor of surgery at the University of North Carolina (UNC), a member of the UNC Lineberger Comprehensive Cancer Center, and head of the current study, had previously discovered, along with her team, that SFRP2 stimulates the growth of blood vessels and is expressed in human breast cancer. They also discovered that SFRP2 activates calcineurin in blood vessel cells.
These findings led to the preclinical trial in which tacrolimus was given orally to breast tumor models, where it inhibited breast tumor growth by more than 70 percent. Klauber-DeMore said that “this pre-clinical study provides a reasoning for the next step, which will be to perform a clinical trial using Tacrolimus in patients with breast cancer.”
As an immunosuppressant, tacrolimus may increase the risk of developing a serious infection. When the immune system is not working normally, there is also an increased risk of developing cancer, especially lymphoma (cancer that starts in the immune system). Other serious side effects may include heart damage, hypertension, liver and kidney problems, and blurry vision. Seizures, swelling of the extremities, decreased urination, unusual bleeding or bruising, and coma also have been noted.
Because tacrolimus already has approval from the Food and Drug Administration (FDA), the clinical trial process differs from that of a new drug. Therefore, Klauber-DeMore noted that “Tacrolimus could potentially go directly into a later stage clinical trial,” and potentially open the door for a new treatment for breast cancer.
University of North Carolina Lineberger Comprehensive Cancer Center