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Jasplakinolide's Inhibition of the Growth of Prostate Carcinoma Cells In Vitro With Disruption of the Actin Cytoskeleton
Background: Jasplakinolide, a cyclo-depsipeptide produced by an Indo-pacific sponge, Jaspis johnstoni, has been reported to inhibit the growth of breast cancer cells. Purpose: The effects of jasplakinolide on the proliferation of three human immortalized prostate carcinoma cell lines (PC-3, LNCaP, a...
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Published in: | JNCI : Journal of the National Cancer Institute 1995-01, Vol.87 (1), p.46-51 |
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Main Authors: | , , , , , , , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that cite this one |
Online Access: | Get full text |
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Summary: | Background: Jasplakinolide, a cyclo-depsipeptide produced by an Indo-pacific sponge, Jaspis johnstoni, has been reported to inhibit the growth of breast cancer cells. Purpose: The effects of jasplakinolide on the proliferation of three human immortalized prostate carcinoma cell lines (PC-3, LNCaP, and TSU-Pr1) were studied. The growth-inhibitory effect of jas-plakinolide on the PC-3 cell line was studied in detail to elucidate its mechanism of action. Methods: Cell counts were used to study growth inhibition. A protein-based microplate assay was used to assess the time of exposure needed to cause persistent growth inhibition and to study the effects of jasplakinolide analogues. Metabolic changes were assessed by following the incorporation of radiolabeled precursors. The effects of jasplakinolide on the cytoskeleton were studied by fluorescent microscopy, using rhoda-mine phalloidin (RP) and antibodies to cytoskeletal components. Changes in RP binding were quantified by extracting bound fluorescent material from fixed cells and measuring the amount of fluorescence in a spectrofluoro-meter. Results: The growth of PC-3, LNCaP, and TSU-Prl cells was potently inhibited by exposure to jasplakinolide for 48 hours; doses of jasplakinolide that led to 50% growth inhibition were 65 nM for PC-3 cells, 41 nM for LNCaP cells, and 170 nM for TSU-Pr1 cells. In PC-3 cells, exposure to 160 nM for 48 hours led to total growth inhibition, which persisted for several days even after drug removal. Several jas-plakinolide analogues also inhibited the growth of PC-3 cells, although analogues in which the rigidity of the macrolide ring was altered were ineffective. No early changes in the synthesis of DNA, RNA, or protein or in intracellular adenosine triphosphate levels were seen in the PC-3 cells after exposure to jasplakinolide. Growth inhibition by jasplakinolide was accompanied by striking morphologic changes. Exposure for several doublings led to multinucleated cells. Further investigation of these changes in the PC-3 cells revealed a dramatic and early disruption of the action cytoskeleton and a statistically significant decrease in RP binding. The doses of jasplakinolide, the time of exposure, and the pattern of growth inhibition by structural analogues corresponded with the changes seen in action distribution. Conclusions: Jasplakinolide represents a novel marine natural product with potent in vitro antiproliferative activity against human prostate carcinoma cell lines, |
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ISSN: | 0027-8874 1460-2105 |
DOI: | 10.1093/jnci/87.1.46 |