Novel Combination Therapy Could Potentially Shrink Breast Cancer Tumors

A combination of doxorubicin, all-trans retinoic acid, and entinostat shrank triple-negative breast cancer tumors by 90%.

In a recent study, researchers discovered that a 3-drug cocktail can shrink triple-negative breast cancer (TNBC) tumors. The combination therapy included the chemotherapy drug doxorubicin, all-trans retinoic acid (ATRA), and entinostat.

ATRA causes tumors to lose self-renewing cells, and entinostat makes the cancer cells more sensitive to ATRA.

The researchers wrote that the triple-drug cocktail (EAD) was able to reduce the size of TNBC tumors in mice and in lab-grown metastatic breast cancer tumor spheres by 90%, according to the study published in Cancer Cell.

Compared with a combination of entinostat and doxorubicin, researchers found that EAD reduced the number of tumor-starting cells two-fold. This suggests that ATRA was able to make the tumor cells turn from stem cell-like to differentiated cells that could be more responsive to treatment.

In tumor spheres, EAD therapy reduced the number of spheres formed by 80% compared with a 40% reduction in doxorubicin monotherapy.

"If the cancer is supplied with agents that can cause their differentiation faster than their production, the tumor will shrink, since more cells are dying than are being produced to replace the dead ones," said study co-author Vanessa Merino, PhD.

Researchers conclude that the next step will be to test the safety and effectiveness of EAD in patients with TNBC.