The apple flavonoid phloretin is found in the flesh and peel of apples and to a lesser extent, pears. Phloretin has been demonstrated to increase the treatment effects of Adriamycin (doxorubicin), Taxol (paclitaxel), cisplatin and tamoxifen. Now a new study has reported that phloretin can also enhance the effectiveness of Herceptin.
Latest research finds phloretin potentiates Herceptin
The study referenced above was designed to investigate the potential of phloretin to enhance the effectiveness of Herceptin (trastuzumab) in HER2+ (HER2/neu overexpressing) breast cancer. The authors first established that phloretin inhibited type II glucose transporter (GLUT2) activity. They also confirmed that GLUT1 and GLUT2 mRNA was overexpressed in human breast cancer tissues. In fact, GLUT2 overexpression was associated with worse survival. Treatment with phloretin was demonstrated to heighten the interaction between GLUT2 and HER2 proteins, enhancing the binding affinity of anti-HER2 antibody drugs to HER2+ breast cancer cells.
The authors then used an animal model of Herceptin-resistant HER2+ breast cancer to test the efficacy of the combination of phloretin plus Herceptin. The combination was shown to suppress the growth of Herceptin-resistant HER2+ breast cancer. The authors conclude that targeting GLUT2 activity with phloretin in combination with anti-HER2 antibody drugs has the potential to enhance tumor treatment.