在细胞壁上构筑自组装的生物矿化结构

芦荟植物在其叶刺细胞壁上利用CaCl_2前体分子合成了非自然状态下形成的生 物钙化结构。合成的生物CaCO_3结构为四棱柱形,直径为2～3 μm,长40～60 μ m。实验发现在场发射电镜持续电子束作用下和冷冻切片断裂作用下均可诱导一系 列人工弯曲和断裂。如此特殊的柔性和刚性与非生物的地球化学条件下形成的矿物 完全不同,表明矿物前体分子和细胞壁表面有机分子间的分子识别作用为矿化结构 的控制提供了较大的机会。     

Inhibition of cell proliferation by a resveratrol analog in human pancreatic and breast cancer cells

Resveratrol has been reported to possess cancer preventive properties. In this study, we analyzed anti-tumor activity of a newly synthesized resveratrol analog, cis-3,4'',5-trimethoxy-3''-hydroxystilbene (hereafter called 11b) towards breast and pancreatic cancer cell lines. 11b treatments reduced the proliferation of human pancreatic and breast cancer cells, arrested cells in the G2/M phase, and increased the percentage of cells in the subG1/G0 fraction. The 11b treatments also increased the total levels of mitotic checkpoint proteins such as BubR1, Aurora B, Cyclin B, and phosphorylated histone H3. Mechanistically, 11b blocks microtubule polymerization in vitro and it disturbed microtubule networks in both pancreatic and breast cancer cell lines. Computational modeling of the 11b-tubulin interaction indicates that the dimethoxyphenyl group of 11b can bind to the colchicine binding site of tubulin. Our studies show that the 11b treatment effects occur at lower concentrations than similar effects associated with resveratrol treatments and that microtubules may be the primary target for the observed effects of 11b. These studies suggest that 11b should be further examined as a potentially potent clinical chemotherapeutic agent for treating pancreatic and breast cancer patients.