Senderowicz A M, Kaur G, Sainz E, Laing C, Inman W D, Rodríguez J, Crews P, Malspeis L, Grever M R, Sausville E A
Laboratory of Biological Chemistry, National Cancer Institute, Bethesda, MD 20892-7456, USA.
J Natl Cancer Inst. 1995 Jan 4;87(1):46-51. doi: 10.1093/jnci/87.1.46.
Jasplakinolide, a cyclodepsipeptide produced by an Indo-Pacific sponge, Jaspis johnstoni, has been reported to inhibit the growth of breast cancer cells.
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 jasplakinolide on the PC-3 cell line was studied in detail to elucidate its mechanism of action.
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 rhodamine 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 spectrofluorometer.
The growth of PC-3, LNCaP, and TSU-Pr1 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 jasplakinolide 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 actin 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 actin distribution.
Jasplakinolide represents a novel marine natural product with potent in vitro antiproliferative activity against human prostate carcinoma cell lines, and it appears to target the actin cytoskeleton.
Jasplakinolide is a potential candidate for further preclinical development and a lead structure for a novel class of therapeutic agents that can disrupt the actin cytoskeleton in mammalian cells.
茉莉素内酯是一种由印度 - 太平洋海绵约翰逊氏海绵（Jaspis johnstoni）产生的环缩肽，据报道可抑制乳腺癌细胞的生长。
研究茉莉素内酯对三种人永生化前列腺癌细胞系（PC - 3、LNCaP和TSU - Pr1）增殖的影响。详细研究了茉莉素内酯对PC - 3细胞系的生长抑制作用，以阐明其作用机制。
使用细胞计数研究生长抑制情况。采用基于蛋白质的微孔板测定法评估引起持续生长抑制所需的暴露时间，并研究茉莉素内酯类似物的作用。通过追踪放射性标记前体的掺入来评估代谢变化。使用罗丹明鬼笔环肽（RP）和细胞骨架成分抗体，通过荧光显微镜研究茉莉素内酯对细胞骨架的影响。通过从固定细胞中提取结合的荧光物质并在荧光分光光度计中测量荧光量，对RP结合的变化进行定量。
PC - 3、LNCaP和TSU - Pr1细胞暴露于茉莉素内酯48小时后，生长受到显著抑制；导致50%生长抑制的茉莉素内酯剂量，PC - 3细胞为65 nM，LNCaP细胞为41 nM，TSU - Pr1细胞为170 nM。在PC - 3细胞中，暴露于160 nM 48小时导致完全生长抑制，即使在去除药物后这种抑制仍持续数天。几种茉莉素内酯类似物也抑制PC - 3细胞的生长，尽管大环内酯环刚性改变的类似物无效。PC - 3细胞暴露于茉莉素内酯后，未观察到DNA、RNA或蛋白质合成或细胞内三磷酸腺苷水平的早期变化。茉莉素内酯引起的生长抑制伴随着显著的形态学变化。经过几次倍增时间的暴露导致多核细胞的形成。对PC - 3细胞中这些变化的进一步研究揭示了肌动蛋白细胞骨架的剧烈早期破坏以及RP结合的统计学显著下降。茉莉素内酯的剂量、暴露时间以及结构类似物的生长抑制模式与肌动蛋白分布的变化相对应。
茉莉素内酯是一种新型海洋天然产物，对人前列腺癌细胞系具有强大的体外抗增殖活性，并且似乎靶向肌动蛋白细胞骨架。
茉莉素内酯是进一步临床前开发的潜在候选物，也是一类新型治疗剂的先导结构，这类治疗剂可破坏哺乳动物细胞中的肌动蛋白细胞骨架。
