Prostate cancer is one of the most frequent and deadly tumors in man. Efficient therapies have been developed these last years for the early stages. Antiandrogen therapy used to block the androgen receptor is used in metastasized forms of the disease. Unfortunately, after few months, a pharmaco-resistant form occurs aggressive tumors could rapidly develop. One of the reasons is the ability of the androgen receptor to be active despite the presence of the antiandrogen. It is therefore essential to look for new molecules that are more effective on the androgen signaling pathway. Natural products are an interesting source of new therapeutics, especially for cancer therapy as 70% of them have botanical origin. Based on an ethnobotany screening, the teams of J.M Lobaccaro/S. Baron & V. Sapin/L. Blanchon have developed a collaborative study with Jijel and Oum El Bouaghi Universities (Algeri) and the CHU Clermont-Ferrand, to evaluate the effects of ethanolic extract of propolis from Algeria on human prostate cancer cells.
Propolis, also known as bee glue, is a sticky and a dark colored material produced by honeybees from leaf buds and cracks in the bark of several tree species. Once collected, this material is enriched with salivary and enzymatic secretions. Its role is to seal cracks of the hives and more importantly to eliminate biological contamination in the colony. The chemical composition of propolis is complex however the major constituents of propolis produced in temperate zones are phenolic compounds, which have been extensively studied to date as antioxidants present in natural products.
This work, published in the Journal of Steroid Biochemistry and Molecular Biology shows for the first time that propolis reduces the survival of LNCaP cells with high efficacy by the induction of the apoptosis as well as blocking the cell cycle. The most interesting fact is however that propolis decreases the androgen receptor signaling pathway at several levels: it acts as a powerful antiandrogen and decreases the amount of androgen receptor in the cells.
Even though isolated components responsible of these antiandrogen effects have not been identified yet, this work provides a scientific basis for the use of propolis in the treatment of the resistant forms of prostate cancer and will allow the development of new specific androgen receptor degraders (SARDs) that would combine both anti-androgen activity and the enhancement of androgen receptor degradation. These compounds are supposed to be more effective antiandrogens, even in castrated resistance PCa.
One more reason to protect bees!
This work, coming from Dr. Nada ZABAIOU PhD work (GReD and Jijel University), was supported by Région Auvergne-Rhône-Alpes, Fond Européen de Développement Régional (FEDER), Plan National de Recherche sur les Perturbateurs Endocriniens (13-MRES-PNRPE-1-CVS043), Projet Hubert Curien Tassili 16-MDU-956, Plan-Cancer Environnement 2016 and Association de Recherche sur les Tumeurs Prostatiques.
For more information : Jean-Marc LOBACCARO (firstname.lastname@example.org) or Silvère BARON (email@example.com)