Caffeic Acid Phenethyl Ester as an Adjuvant Therapy for Advanced
Prostate Cancer
Prostate cancer is the second most frequently diagnosed
cancer of men. Androgen ablation therapy is the primary treatment for
metastatic prostate cancer. However, the majority of prostate cancer patients
receiving the androgen ablation therapy will ultimately develop recurrent
castration-resistant tumors within 3years.
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. Caffeic
acid phenethyl ester (CAPE) is a strong antioxidant extracted from honeybee
hive propolis. Recent studies indicate that CAPE treatment suppresses tumor
growth and Akt signaling in human prostate cancer cells. Combined treatments of
CAPE with chemotherapeutic drugs exhibit synergistic suppression effects.
Pharmacokinetic studies suggest that intraperitoneal injection of CAPE at
concentration of 10mg/kg is not toxic.
CAPE treatment sensitizes cancer cells to chemotherapy and
radiation treatments. In addition, CAPE treatment protects therapy-associated
toxicities in animal models. We therefore propose that administration of CAPE
is a potential adjuvant therapy for patients with castration-resistant prostate
cancer.