Caffeic Acid Phenethyl Ester as a Potential Treatment for Advanced Prostate Cancer Targeting Akt Signaling

Prostate cancer is the fifth most common cancer overall in the world. Androgen ablation therapy is the primary treatment for metastatic prostate cancer. However, most prostate cancer patients receiving the androgen ablation therapy ultimately develop recurrent castration-resistant tumors within 1–3 years after treatment. The median overall survival time is 1–2 years after tumor relapse. Chemotherapy shows little effect on prolonging survival for patients with metastatic hormone-refractory prostate cancer. More than 80% of prostate tumors acquire mutation or deletion of tumor suppressor phosphatase and tensin homolog (PTEN), a negative regulator of PI3K/Akt signaling, indicating that inhibition of PI3K/Akt might be a potential therapy for advanced prostate tumors. Caffeic acid phenethyl ester (CAPE) is a strong antioxidant extracted from honeybee hive propolis. CAPE is a well-known NF-κB inhibitor. CAPE has been used in folk medicine as a potent anti-inflammatory agent. Recent studies indicate that CAPE treatment suppresses tumor growth and Akt signaling in human prostate cancer cells. We discuss the potential of using CAPE as a treatment for patients with advanced prostate cancer targeting Akt signaling pathway in this review article.