Background RNA interference （RNAi） technology is emerging as a very potent tool to generate a cellular knockdown of a desired gene. The aim of this study was to explore whether RNAi targeting vascular endothelial gr...Background RNA interference （RNAi） technology is emerging as a very potent tool to generate a cellular knockdown of a desired gene. The aim of this study was to explore whether RNAi targeting vascular endothelial growth factor-C （VEGF-C） could inhibit colorectal tumor lymphangiogenesis and tumor growth. Methods We used vector-based RNAi to inhibit VEGF-C expression in colon cancer in vitro and in vivo. VEGF-C expression was quantified by real-time polymerase chain reaction and Westen blotting. To establish LoVo cell tumor xenografts in mice, we subcutaneously inoculated 1.0×10^6 LoVo cells in nude mice; after injection, tumors were allowed to grow for 4 weeks until the volume reached （75.80± 55.8）mm^3. The mice were then randomly divided into two groups： （1） the VEGF-C-siRNA group （n= 10） received direct injection of ＂therapeutic＂ plasmid 50 IJg of LoVo-VEGF-C-siRNA into the tumor mass; （2） the control group （n= 10） were injected with LoVo-control in 20 IJI of sterile 0.9% NaCI solution into the tumor mass. Tumor growth, microlymphatics and microvessels were compared for mice administered either systemic VEGF-C-siRNA or control over 4 weeks. Results The mRNA and protein expression of VEGF-C in the colon tumor cell line, LoVo, stably transfected with a VEGF-C-siRNA vector, were significantly downregulated 45.3% and 35.3% respectively. In vivo, four weeks after injection, the tumor volume were significantly smaller in VEGF-C-siRNA group than in LoVo-control group （（314.8 ± 54.8） mm3 vs （553.9 ± 90.1） mm3）; the incidences of lymph node metastasis （30%） in VEGF-C-siRNA were significantly inhibited compared with LoVo-control group （70%）; in VEGF-C-siRNA group, the number of microlymphatics per microscopic field was （5.3 ± 0.7） and the number of microvessels per microscopic field was （24.2 ± 6.5） decreased compared with LoVo-control group （12.5 ± 6.9） and （42.1 ± 7.4） （all P〈0.001）. Conclusion Inhibition of VEGF-C expression using siRNA展开更多
The karst process acts as carbon sequestration for atmospheric CO_2.The amount of karst carbon sequestration (KCS) depends on the discharge of karst catchment and inorganic carbon concentration of the water body.Based...The karst process acts as carbon sequestration for atmospheric CO_2.The amount of karst carbon sequestration (KCS) depends on the discharge of karst catchment and inorganic carbon concentration of the water body.Based on the data from the monitoring station on Banzhai subterranean stream located in Maolan National Nature Reserve of Guizhou province,the process and influence factors of KCS have been analyzed.It shows that the amount of KCS is about 353 t C per year in the catchment of Banzhai subterranean stream,and there is good linear relationship between the strength of KCS and discharge of the stream at various time scales.Therefore,how to monitor the discharge accurately is the key to the estimation of KCS.And stations with real-time monitoring function are very important for KCS calculation because of strong seasonal variability of the karst water cycle.展开更多
文摘Background RNA interference （RNAi） technology is emerging as a very potent tool to generate a cellular knockdown of a desired gene. The aim of this study was to explore whether RNAi targeting vascular endothelial growth factor-C （VEGF-C） could inhibit colorectal tumor lymphangiogenesis and tumor growth. Methods We used vector-based RNAi to inhibit VEGF-C expression in colon cancer in vitro and in vivo. VEGF-C expression was quantified by real-time polymerase chain reaction and Westen blotting. To establish LoVo cell tumor xenografts in mice, we subcutaneously inoculated 1.0×10^6 LoVo cells in nude mice; after injection, tumors were allowed to grow for 4 weeks until the volume reached （75.80± 55.8）mm^3. The mice were then randomly divided into two groups： （1） the VEGF-C-siRNA group （n= 10） received direct injection of ＂therapeutic＂ plasmid 50 IJg of LoVo-VEGF-C-siRNA into the tumor mass; （2） the control group （n= 10） were injected with LoVo-control in 20 IJI of sterile 0.9% NaCI solution into the tumor mass. Tumor growth, microlymphatics and microvessels were compared for mice administered either systemic VEGF-C-siRNA or control over 4 weeks. Results The mRNA and protein expression of VEGF-C in the colon tumor cell line, LoVo, stably transfected with a VEGF-C-siRNA vector, were significantly downregulated 45.3% and 35.3% respectively. In vivo, four weeks after injection, the tumor volume were significantly smaller in VEGF-C-siRNA group than in LoVo-control group （（314.8 ± 54.8） mm3 vs （553.9 ± 90.1） mm3）; the incidences of lymph node metastasis （30%） in VEGF-C-siRNA were significantly inhibited compared with LoVo-control group （70%）; in VEGF-C-siRNA group, the number of microlymphatics per microscopic field was （5.3 ± 0.7） and the number of microvessels per microscopic field was （24.2 ± 6.5） decreased compared with LoVo-control group （12.5 ± 6.9） and （42.1 ± 7.4） （all P〈0.001）. Conclusion Inhibition of VEGF-C expression using siRNA
基金funded by the project (No.41072192)from National Natural Science Foundation of Chinathe project(No.1212011087122)from China Geological Survey
文摘The karst process acts as carbon sequestration for atmospheric CO_2.The amount of karst carbon sequestration (KCS) depends on the discharge of karst catchment and inorganic carbon concentration of the water body.Based on the data from the monitoring station on Banzhai subterranean stream located in Maolan National Nature Reserve of Guizhou province,the process and influence factors of KCS have been analyzed.It shows that the amount of KCS is about 353 t C per year in the catchment of Banzhai subterranean stream,and there is good linear relationship between the strength of KCS and discharge of the stream at various time scales.Therefore,how to monitor the discharge accurately is the key to the estimation of KCS.And stations with real-time monitoring function are very important for KCS calculation because of strong seasonal variability of the karst water cycle.
