BERKELEY, CA (UroToday.com) - Epidemiologic studies show that high level of cruciferous vegetable intake may lower the risk of cancer, including prostate cancer. One of the best-studied chemopreventive constituents of these plants is sulforaphane (SFN), abundant especially in broccoli and broccoli sprouts. It protects against carcinogenesis by inducing enzymes engaged in detoxification of carcinogens and inhibiting activation of pro-carcinogens. Moreover, SFN blocks cancer development at post-initiation phases as well, inhibiting proliferation and inducing cancer cells death. It has been previously demonstrated that oral administration of SFN retarded the growth of PC-3 human prostate xenografts in athymic mice and inhibited prostate carcinogenesis and pulmonary metastasis in transgenic mouse model of prostate cancer. In vitro studies using different human prostate cancer cell lines, revealed that SFN induced oxidative stress and caspase-dependent cell death.
Our present study shows another mechanism of SFN activity: inhibition of protein synthesis, a process essential for cell viability and proliferation and thus often upregulated in human cancers. At the molecular level, SFN- induced translation block in prostate, as well as breast cancer cells, is connected with the inhibition of mTOR-S6K1 signaling and is independent of mitochondria-derived reactive oxygen species induced by SFN. Translation inhibition might be a protective response of prostate cancer cells to save energy. However, it finally leads to depletion of a short-lived surviving, which is a protein crucial for prostate tumor viability and progression and thus often overexpressed in cancer cells.
Our findings on mechanisms of anti-cancer activity of SFN need to be proven in the in vivo system. Future clinical trials should evaluate anti-tumor potency of SFN in prostate cancer patients, and detection of survivin level in blood might be a good marker of therapy progression.
Written by:
Anna Herman-Antosiewicz, PhD, DSc as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.
Department of Molecular Biology, University of Gdańsk, Kładki 24, 80‐822 Gdańsk, Poland
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