July 11, 2005
Curry Spice Shuts Down MelanomaTopics: Skin Cancer
Turmeric (Curcuma longa), also known as curcumin), is one of the most studied chemopreventive agents. It is a natural compound extracted from Curcuma longa L. that allows suppression, retardation or inversion of carcinogenesis. Curcumin is also described as an anti-tumoral, anti-oxidant and anti-inflammatory agent capable of inducing apoptosis in numerous cellular systems (Curcumin-induced apoptosis is known to involve mainly the mitochondria-mediated pathway in various cancer cells of different tissues of origin). The diverse mechanisms for the anti-cancer activities continue to be researched, and so far seem to be by multiple and complementary pathways. The following article in Forbes.com focuses on the effects of curcumin on melanoma, a skin cancer that is notoriously resistant to all current modalities of cancer therapy.
- MONDAY, July 11 (HealthDay News) via Forbes.com
Curcumin, the ingredient that gives curry its yellow hue, blocked the growth of melanoma tumor cells and even stimulated their death in the laboratory, researchers report.
"We could completely inhibit the growth of the tumor if we used a big enough dose," said study co-author Bharat B. Aggarwal, chief of the Cytokine Research Section in the Department of Experimental Therapeutics at the University of Texas M.D. Anderson Cancer Center in Houston. His report is set to appear in the Aug. 15 issue of Cancer.
Aggarwal and his colleagues exposed three different cell lines of melanoma to curcumin, which is found in turmeric, a spice used in curry dishes. Exposure to curcumin decreased the cell viability of all three cell lines, they found.
They zeroed in on a molecule called NF-kappa B, which is known to be overactive in several types of tumors, including melanoma. The turmeric shut down the molecule and that lead to inhibition of the tumor growth, Aggarwal explained.
In other preliminary research, including some by Aggarwal's team, turmeric has proven useful in treating multiple myeloma, as well as breast and pancreatic cancers.
The new findings were praised by Costas Koumenis, an associate professor of radiation oncology at Wake Forest University School of Medicine. "I think it's an interesting and provocative study," he said. "It shows some new insight into how turmeric is working to inhibit the growth of melanoma cells."
Koumenis is studying whether curcumin can be used to enhance radiation therapy in deadly brain tumors called gliomas and other tumors in animals.
The Texas researchers also pinpointed exactly how the spice ingredient works to kill tumor cells, he said. "It gives us a better understanding of the mechanism of how it works to inhibit melanoma growth."
But he cautioned that the study was done in the lab, and the spice must be tested on animals, and eventually people, before it is proven to be effective.
For the past 20 years, Koumenis said, turmeric has been studied, mostly as an agent to prevent cancer. For instance, some researchers have found an association between diets rich in curcumin and reduced rates of colon cancer. But more recently, the focus has shifted to study the spice as a cancer treatment.
Interestingly, the 'known' mechanisms for the anticarcinogenic effects of curcumin are similar to those of the green tea polyphenols(GTPs). Curcumin enhances glutathione content and glutathione-S-transferase activity in liver; and it inhibits lipid peroxidation and arachidonic acid metabolism in mouse skin, protein kinase C activity in TPA-treated NIH 3T3 cells, chemically induced ODC and tyrosine protein kinase activities in rat colon, and 8-hydroxyguanosine formation in mouse fibroblasts.
As for green tea, like with curcumin, several of the 'known' mechanisms appear to be responsible for the tumor-inhibitory properties of the GTPs, including enhancement of antioxidant (glutathione peroxidase, catalase and quinone reductase) and phase II (glutathione-S-transferase) enzyme activities; inhibition of chemically induced lipid peroxidation; inhibition of irradiation- and TPA-induced epidermal ornithine decarboxylase (ODC) and cyclooxygenase activities; inhibition of protein kinase C and cellular proliferation; antiinflammatory activity; and enhancement of gap junction intercellular communication.
Polyphenols as cancer chemopreventive agents.
Antitumor effects of curcumin, alone or in combination with cisplatin or doxorubicin, on human hepatic cancer cells. Analysis of their possible relationship to changes in NF-kB activation levels and in IAP gene expression.
Posted by Richard at July 11, 2005 4:16 PM
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