Background Bcl-2, the anti-apoptotic protein is overexpressed in the majority of gastric cancers and associated with its pathogenesis. To better understanding of the role of Bcl-2, RNA interference （RNAi） was used t...Background Bcl-2, the anti-apoptotic protein is overexpressed in the majority of gastric cancers and associated with its pathogenesis. To better understanding of the role of Bcl-2, RNA interference （RNAi） was used to inhibit Bcl-2 expression in the human gastric cancer cells in vitro and in vivo. Methods Bcl-2 small interfering RNA （siRNA） was transfected into human gastric cancer cells $GC-7901, and Bcl-2 expression was monitored by real-time polymerase chain reaction （PCR） and Western blot. Cell proliferation, apoptosis, and telomerase activity were examined by MTT, flow cytometry, and TRAP assay, respectively. Gastric cancer cells treated with 100 nmol/L Bcl-2 siRNA were subcutaneously transplanted into nude mice and tumor growth was assessed. Results Bcl-2 siRNA significantly inhibited the expression of Bcl-2 in human gastric cancer cells at both mRNA and protein levels in a time- and dose-dependent manner. Bcl-2 siRNA also decreased telomerase activity （by 78.76%） and increased the rate of apoptosis （by 37.47%）. SGC-7901 cell growth was also significantly suppressed in vivo and in vitro. Conclusions Bcl-2 expression knockdown suppressed the growth of gastric cancer cells. Thus, Bcl-2 may play a very important role in carcinogenesis of gastric cancer and its knockdown may offer a new potential gene therapy approach for human gastric cancer in future.展开更多
Background Genetic modification of dendritic cells （DCs） has been used as an effective approach to enhance anti-tumor immunity. RNA interference （RNAi）, which can cause the degradation of any RNA in a sequence-spe...Background Genetic modification of dendritic cells （DCs） has been used as an effective approach to enhance anti-tumor immunity. RNA interference （RNAi）, which can cause the degradation of any RNA in a sequence-specific manner, is a post-transcriptional gene silencing mechanism. In this study, small-interfering RNA （siRNA） specific for the li gene was transfected into DCs, and the anti-tumor immunity of li-silenced DCs was assessed. Methods The silencing effect of siRNA was evaluated by Western blotting and real-time PCR analyses. In vitro cytotoxic activity of T cells was evaluated using a Cytotox 96 non-radioactive cytotoxicity assay kit. The time to tumor onset and the tumor volumes were used as reliable indices to assess the anti-tumor immunity in vivo. To further examine the mechanisms underlying the anti-tumor immunity, flow cytometry analysis was used. Results The li expression of DCs was significantly reduced after li siRNA transfection. Significant in vitro anti-tumor ability was exhibited when DCs were co-transfected with li siRNA plus endogenous tumor antigen （P 〈0.05）. Furthermore tumor growth was greatly inhibited when mice were immunized with DCs transfected with li siRNA plus tumor antigen prior to or subsequent to tumor implantation. Flow cytometry analysis in vitro and in vivo indicated that both CD4^= and CD8^＋ T cells were significantly activated in the li siRNA group （P 〈0.05）. Conclusion Silencing of the li gene of DCs may offer a potential approach to enhance DC-based anti-tumor immunity.展开更多
In this paper, an efficient sparse representation-based method is presented for detecting surface defects. The proposed method uses the sparse degree of coefficient in the redundant dictionary for checking whether the...In this paper, an efficient sparse representation-based method is presented for detecting surface defects. The proposed method uses the sparse degree of coefficient in the redundant dictionary for checking whether the test image is defective or not, and the binary representation of the defective images is obtained, according to the global coefficient feature. Owing to the requirements for the efficiency and detecting quality, the block proximal gradient operator is introduced to speed up the online dictionary learning. Considering the correlation among the testing samples, prior knowledge is applied in the orthogonal-matching-pursuit sparse representation algorithm to improve the speed of sparse coding. Experimental results demonstrate that the proposed detection method can effectively detect and extract the defects of the surface images, and has broad applicability.展开更多
基金the grants from Shanghai Medical Key Discipline (No.05Ⅲ005)the National High Technology and Development Program of China(863 Program,No.2002BA7111A06).
文摘Background Bcl-2, the anti-apoptotic protein is overexpressed in the majority of gastric cancers and associated with its pathogenesis. To better understanding of the role of Bcl-2, RNA interference （RNAi） was used to inhibit Bcl-2 expression in the human gastric cancer cells in vitro and in vivo. Methods Bcl-2 small interfering RNA （siRNA） was transfected into human gastric cancer cells $GC-7901, and Bcl-2 expression was monitored by real-time polymerase chain reaction （PCR） and Western blot. Cell proliferation, apoptosis, and telomerase activity were examined by MTT, flow cytometry, and TRAP assay, respectively. Gastric cancer cells treated with 100 nmol/L Bcl-2 siRNA were subcutaneously transplanted into nude mice and tumor growth was assessed. Results Bcl-2 siRNA significantly inhibited the expression of Bcl-2 in human gastric cancer cells at both mRNA and protein levels in a time- and dose-dependent manner. Bcl-2 siRNA also decreased telomerase activity （by 78.76%） and increased the rate of apoptosis （by 37.47%）. SGC-7901 cell growth was also significantly suppressed in vivo and in vitro. Conclusions Bcl-2 expression knockdown suppressed the growth of gastric cancer cells. Thus, Bcl-2 may play a very important role in carcinogenesis of gastric cancer and its knockdown may offer a new potential gene therapy approach for human gastric cancer in future.
基金This research was supported by grants from the National Natural Science Foundation of China （No. 30570828 and No. 30471961）.Acknowledgements： The authors deeply appreciate technical assistance from Q. Li and D. Q. Zhang valuble discussion with R. F Ge and help from the experimental Animal Facility technicians for animal care. We thank the International Science Editing for help in editing our manuscript.
文摘Background Genetic modification of dendritic cells （DCs） has been used as an effective approach to enhance anti-tumor immunity. RNA interference （RNAi）, which can cause the degradation of any RNA in a sequence-specific manner, is a post-transcriptional gene silencing mechanism. In this study, small-interfering RNA （siRNA） specific for the li gene was transfected into DCs, and the anti-tumor immunity of li-silenced DCs was assessed. Methods The silencing effect of siRNA was evaluated by Western blotting and real-time PCR analyses. In vitro cytotoxic activity of T cells was evaluated using a Cytotox 96 non-radioactive cytotoxicity assay kit. The time to tumor onset and the tumor volumes were used as reliable indices to assess the anti-tumor immunity in vivo. To further examine the mechanisms underlying the anti-tumor immunity, flow cytometry analysis was used. Results The li expression of DCs was significantly reduced after li siRNA transfection. Significant in vitro anti-tumor ability was exhibited when DCs were co-transfected with li siRNA plus endogenous tumor antigen （P 〈0.05）. Furthermore tumor growth was greatly inhibited when mice were immunized with DCs transfected with li siRNA plus tumor antigen prior to or subsequent to tumor implantation. Flow cytometry analysis in vitro and in vivo indicated that both CD4^= and CD8^＋ T cells were significantly activated in the li siRNA group （P 〈0.05）. Conclusion Silencing of the li gene of DCs may offer a potential approach to enhance DC-based anti-tumor immunity.
基金supported by the Zhejiang Provincial Natural Science Foundation of China(No.LZ14F030001)
文摘In this paper, an efficient sparse representation-based method is presented for detecting surface defects. The proposed method uses the sparse degree of coefficient in the redundant dictionary for checking whether the test image is defective or not, and the binary representation of the defective images is obtained, according to the global coefficient feature. Owing to the requirements for the efficiency and detecting quality, the block proximal gradient operator is introduced to speed up the online dictionary learning. Considering the correlation among the testing samples, prior knowledge is applied in the orthogonal-matching-pursuit sparse representation algorithm to improve the speed of sparse coding. Experimental results demonstrate that the proposed detection method can effectively detect and extract the defects of the surface images, and has broad applicability.
