Y. Fujita, Kazuko Matsumoto, Kaoru Tanaka
May 1, 2009
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Cancer Research
Abstract
Uncaria tomentosa (cat\#8217;s claw), a South American Rubiaceae, has been recently more and more popular as an immunomodulatory, anti-inflammatory and anti-cancer remedy. Here we show that the antiproliferative and apoptotic effects of pentacyclic oxindole alkaloids (POAs) purified from U. tomentosa , namely pteropodine, isopteropodine, mitraphylline, isomitraphylline and speciophylline on various types of human cancer cell lines. MTT assay revealed that, with the exception of mitraphylline, all alkaloids tested inhibited the growth of several cells. Pteropodine and isopteropodine, particularly, were the most potent with the IC50 of ~5 \#956;M on PC3 (prostate cancer) and WiDr (colon cancer) cells. A549 (lung cancer), Hela (cervical cancer) and MCF7 (breast cancer) cells were also sensitive to these two POAs, although to a lesser extent. Interestingly, T98G (glioblastoma) cells showed no response to these POAs, suggesting the cell-specific inhibitory effect of the POAs. Flow cytometry and immunoblotting analyses of PC3 and WiDr showed that pteropodine arrested these cells at G1 phase and reduced the expression levels of G1-specific cdks (cdks 2 and 4). Annexin-V staining of PC3 suggested that pteropodine induced apoptosis of the cells in a concentration-dependent manner. These findings suggest that the specific POAs from U. tomentosa may be a possible candidate for anti-tumor agent. In vivo antitumor activity of the POAs will be also presented. Citation Information: In: Proc Am Assoc Cancer Res; 2009 Apr 18-22; Denver, CO. Philadelphia (PA): AACR; 2009. Abstract nr 2671.