34-, 17-, 4-, 1.5-year old natural algal crusts were collected from Shapotou Scientific Station of the Chinese Academy of Sciences, 40-day old field and greenhouse artificial algal crusts were in situ developed in the...34-, 17-, 4-, 1.5-year old natural algal crusts were collected from Shapotou Scientific Station of the Chinese Academy of Sciences, 40-day old field and greenhouse artificial algal crusts were in situ developed in the same sandy soil and the same place (37°27’N, 104°57’E). Their different cohesions both against wind force and pressure were measured respectively by a sandy wind-tunnel experiment and a penetrometer. On the basis of these algal crusts, the cementing mechanism was revealed from many subjects and different levels. The results showed that in the indoor artificial crusts with the weakest cohesion bunchy algal filaments were distributed in the surface of the crusts, produced few extracellular polymers (EPS), the binding capacity of the crusts just accomplished by mechanical bundle of algal filaments. For field crusts, most filaments grew toward the deeper layers of algal crusts, secreted much more EPS, and when organic matter content was more than 2.4 times of chlorophyll a, overmuch organic展开更多
Background Studies have shown that the drug resistance of gastric cancer cells can be modulated by abnormal expression of microRNAs （miRNAs）.We investigated the role of miR-503 in the development of cisplatin resist...Background Studies have shown that the drug resistance of gastric cancer cells can be modulated by abnormal expression of microRNAs （miRNAs）.We investigated the role of miR-503 in the development of cisplatin resistance in human gastric cancer cell lines.Methods MiR-503 expression was measured by quantitative real-time PCR.MTT （3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide） and clonogenic assays were used to examine changes in cell viability and the drug resistance phenotype of cancer cells associated with upregulation or downregulation of the miRNA.A dual-luciferase activity assay was used to verify target genes of miR-503.Immunohistochemistry,Western blotting analysis,and a flow cytometric apoptosis assay were used to elucidate the mechanism by which miR-503 modulates drug resistance in cancer cells.Results MiR-503 was significantly downregulated in gastric cancer tissues and several gastric cancer cell lines.Additionally,downregulation of miR-503 in the cisplatin （DDP）-resistant gastric cancer cell line SGC7901/DDP was concurrent with the upregulation of insulin-like growth factor-1 receptor （IGF1R） and B-cell lymphoma 2 （BCL2） expression compared with the parental SGC7901 cell line.An in vitro drug sensitivity assay showed that overexpression of miR-503 sensitized SGC7901/DDP cells to cisplatin.The luciferase activity of reporters driven by IGF1R and BCL2 3＇-untranslated regions in SGC7901/DDP cells suggested that IGF1R and BCL2 were both direct target genes of miR-503.Enforced miR-503 expression in SGC7901/DDP cells reduced expression of the target proteins,inhibited proliferation,and sensitized the cells to DDP-induced apoptosis.Conclusion Our findings suggest that hsa-miR-503 modulates cisplatin resistance of human gastric cancer cells at least in part by targeting IGF1R and BCL2.展开更多
基金This work was supported by The Key Project of The Chinese Academy of Sciences (Grant No. KZ952-51-207)the National Natural Science Foundation of China (Grant No. 30070154, 30170022) Mid-youth Natural Science Foundation of Gansu (Grant No.YS-011-A25-0
文摘34-, 17-, 4-, 1.5-year old natural algal crusts were collected from Shapotou Scientific Station of the Chinese Academy of Sciences, 40-day old field and greenhouse artificial algal crusts were in situ developed in the same sandy soil and the same place (37°27’N, 104°57’E). Their different cohesions both against wind force and pressure were measured respectively by a sandy wind-tunnel experiment and a penetrometer. On the basis of these algal crusts, the cementing mechanism was revealed from many subjects and different levels. The results showed that in the indoor artificial crusts with the weakest cohesion bunchy algal filaments were distributed in the surface of the crusts, produced few extracellular polymers (EPS), the binding capacity of the crusts just accomplished by mechanical bundle of algal filaments. For field crusts, most filaments grew toward the deeper layers of algal crusts, secreted much more EPS, and when organic matter content was more than 2.4 times of chlorophyll a, overmuch organic
基金This research was supported by grants from the National Natural Science Foundation of China （No.81201705 and No.81201796） and the Natural Science Foundation of Jiangsu Province （No.BK2012442）.
文摘Background Studies have shown that the drug resistance of gastric cancer cells can be modulated by abnormal expression of microRNAs （miRNAs）.We investigated the role of miR-503 in the development of cisplatin resistance in human gastric cancer cell lines.Methods MiR-503 expression was measured by quantitative real-time PCR.MTT （3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide） and clonogenic assays were used to examine changes in cell viability and the drug resistance phenotype of cancer cells associated with upregulation or downregulation of the miRNA.A dual-luciferase activity assay was used to verify target genes of miR-503.Immunohistochemistry,Western blotting analysis,and a flow cytometric apoptosis assay were used to elucidate the mechanism by which miR-503 modulates drug resistance in cancer cells.Results MiR-503 was significantly downregulated in gastric cancer tissues and several gastric cancer cell lines.Additionally,downregulation of miR-503 in the cisplatin （DDP）-resistant gastric cancer cell line SGC7901/DDP was concurrent with the upregulation of insulin-like growth factor-1 receptor （IGF1R） and B-cell lymphoma 2 （BCL2） expression compared with the parental SGC7901 cell line.An in vitro drug sensitivity assay showed that overexpression of miR-503 sensitized SGC7901/DDP cells to cisplatin.The luciferase activity of reporters driven by IGF1R and BCL2 3＇-untranslated regions in SGC7901/DDP cells suggested that IGF1R and BCL2 were both direct target genes of miR-503.Enforced miR-503 expression in SGC7901/DDP cells reduced expression of the target proteins,inhibited proliferation,and sensitized the cells to DDP-induced apoptosis.Conclusion Our findings suggest that hsa-miR-503 modulates cisplatin resistance of human gastric cancer cells at least in part by targeting IGF1R and BCL2.
