Birch-bark Extract, Betulinic Acid, Inhibits Prostate Cancer Growth
Stephen Safe, Ph.D.
Texas A&M University Health Science Center
P30ES009106
Betulinic acid is an oxidation product of betulin a traditional medicine product of the triterpene family that is derived from birch tree bark. Previous research characterized it as an effective inhibitor of human melanoma tumor growth through the induction of apoptosis. Other triterpenoid compounds have the same anticarcinogenic and anti-inflammatory effects and are currently being studied in clinical trials for their potential use in treating leukemia.
A group of NIEHS-supported researchers at the Texas A&M Health Sciences Center reports that betulinic acid might also be an effective treatment from prostate cancer. In a series of experiments using prostate cancer cell cultures and an animal model of prostate cancer, betulinic acid treatment decreased the growth of the cancer cells. Further work elucidated the mechanism of betulinic acid’s effect. The compound induced proteosome-dependent degradation of the specificity protein transcription factors Sp1, Sp3, and Sp4 in the prostate cancer cells. These factors are overexpressed in many tumor types.
These results indicate the anti-tumor effects of betulinic acid are associated with specific degradation of specificity protein transcription factors resulting in the inhibition of blood vessel formation and the activation of proapoptotic responses in tumors but not in non-target tissues exhibiting low specificity protein expression. Ongoing studies with betulinic acid are investigating tumor-type similarities and more potent formulations for possible new chemotherapeutic agents.
Citation: Chintharlapalli S, Papineni S, Ramaiah SK, Safe S. Betulinic acid inhibits prostate cancer growth through inhibition of specificity protein transcription factors. Cancer Res. 2007 Mar 15;67(6):2816-23
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