Another post prompted by Attitude67 & Charmander.
Propolis is a resin that bees use to seal gaps in the hive. It may have antibacterial & antifungal properties. Supplements are widely available, but one should be aware that PCa studies have focussed on CAPE (Caffeic Acid Phenethyl Ester). Some propolis has no CAPE at all.
CAPE Studies:
[1] "Caffeic acid phenethyl ester synergistically enhances docetaxel and paclitaxel cytotoxicity in prostate cancer cells"
Of great interest to me was the effect of CAPE on the estrogen receptors ERalpha & ERbeta. Normal prostatic epithelial cells have little or no ERalpha. They do have ERbeta, which resists the paracrine pro-growth influence of ERalpha in the stroma. When PCa develops in epithelial cells, ERbeta expression is suppressed & ERalpha emerges. This is the reason I inhibit aromatase, the enzyme that converts testosterone to estradiol [E2]. PCa cells produce aromatase. {I aim for E2 to be ~20 pg/mL; certainly no lower than 12 (for bone health) & no higher than 30 (for cardiovascular health.)}
In the study:
"Estrogen receptor-β (ER-β) and its downstream tumor suppressor forkhead box O1 levels were significantly elevated in CAPE and combination groups compared to DOC or PTX-alone"
"ER-α and insulin-like growth factor-1 receptor protein abundance were reduced in the same groups."
Typically, there is a lack of interest in the role of estradiol in PCa, & Dr. Myers dismissed the idea when a patient asked him about it. I find this odd, since the changes I mention occur well before any changes to the androgen receptor, & those changes are largely a response to treatment.
[2] "Caffeic Acid Phenethyl Ester as a Potential Treatment for Advanced Prostate Cancer Targeting Akt Signaling" This a review paper - full text below.
Akt aside, I found the following to be promising:
"CAPE treatments have been shown to sensitize cancer cells to chemotherapeutic drugs and radiation treatment by inhibiting pathways that lead to treatment resistance in animal models [122]. CAPE is a protective agent from therapy-associated toxicities in animal models [122]. Doxorubicin is a chemotherapy drug used for hematological malignancies with side effects including acute renal failure [122]. CAPE treatment protected renal, heart, and brain tissues damages caused by doxorubicin treatment in rats [123–125]. Cisplatin is one of the most widely used chemotherapeutic agents for treatment of solid tumors. CAPE treatment protected liver damage caused by cisplatin treatment [126,127]. Methotrexate is an anti-metabolite and anti-folate drug used in treatment of cancer, autoimmune diseases, ectopic pregnancy, and induction of medical abortions. CAPE treatment protected methotrexate-induced renal oxidative impairment in rats [128]. Bleomycin is a glycopeptide antibiotic generated from bacterium Streptomyces verticillus. Bleomycin causes breaks in DNA and is used as a chemotherapy agent for several types of cancers. CAPE treatment inhibited bleomycin-induced lung fibrosis [129]. Tamoxifen is an antagonist of the estrogen receptor (ER) in breast tissue via its active metabolite, hydroxytamoxifen. Tamoxifen is the most common treatment for ER-positive breast cancer in pre-menopausal women. CAPE treatment significantly prevented liver toxicity induced by Tamoxifen treatment [130]. Co-treatment with CAPE and five chemotherapeutic agents commonly used in prostate cancers showed additive suppressive effects in PC-3 cells [71]. CAPE treatment attenuated radiation treatment-induced pulmonary injury in vivo[131]. CAPE treatment sensitized colorectal adenocarcinomas to radiation treatment without affecting bone marrow radio-response in animal model [132]. Therefore, treatment with CAPE not only may suppress tumor growth in patients but also may protect patients from chemotherapy or radiation therapy."
The best source of CAPE appears to be propolis from New Zealand:
manukahealth.co.nz/bio_new_...
-Patrick
Inhibition of estrogen signaling through depletion of estrogen receptor alpha by ursolic acid and betulinic acid from Prunella vulgaris var.
CRPC - causes and prevention of 
