Umor cells infected with different MOIs of Ad?(ST13)?CEA?E1A(D24). CEAnegative colon cancer cell line (Colo-320) and CEA-positive non-colon cancer cell line (A549, MCF-7) were infected with Ad?(ST13)?CEA?E1A(D24) at a range of MOIs (0.1, 1, 5 or 10 MOI), 
3 days, cell viability was determined using an MTT assay. Bars represent the means 6 SD (n = 6). doi:10.1371/journal.pone.0047566.gexperimental procedures were approved by the Institutional Animal Care and Use Committee of Shanghai Institute of Biochemistry and Cell Biology under protocol IBCB-SPF0029. Xenografted mice were used as a model system to study the cytotoxic effects of SW620 cells (Chinese Academy of Sciences, Shanghai, China) in vivo. SW620 cells (56106/100 mL) were injected subcutaneously into the lower right flank of female nude mice to establish the tumor xenograft model. The tumor volume (V), which was based on caliper measurements, was calculated using the formula V (mm3) = length (mm)6width (mm) 2/2. After the tumors reached 100 to 130 mm3 in size, the mice were randomly divided into control and treatment groups (n = 8). The treatment groups were administrated intratumorally at the consecutive daily doses of 56108 plaque-forming units (PFU)/ 100 mL of either ONYX-015, Ad?(EGFP)?CEA?E1A(D24), Ad (ST13)?CEA?E1A(D24) for four days. The control group was treated with consecutive intratumoral injections four times with the same volume of PBS.was immediately immersed into 4 paraformaldehyde, where it was kept 25837696 for 48 h at room temperature and then embedded into paraffin. Afterward, the samples were cut into 4-mm-thick sections. Immunohistochemistry was performed with an anti-adenoviral hexon or anti-ST13 antibody (Biodesign International, Saco, ME) using an immunohistochemistry kit according to the manufacturer’s protocol. In addition, pathological changes in the tumor tissue were examined after hematoxylin and eosin 
(H E) staining and TUNEL staining as well as by transmission electric microscopy (TEM).Statistical AnalysisAll data are presented as the mean 6 SD and were processed using the SPSS 10.1 statistical software. Each quantitative experiment was carried out at least three times, and statistical significance was assigned for P values #0.05.Results Construction and Characterization of Ad?(ST13)?CEA?E1A(D24)The Ad?(ST13)?CEA?E1A(D24) vector was successfully constructed by replacing the native E1A promoter with the colorectal cancer-specific CEA promoter, deleting 24 bp in Ad?E1A (923?��-Sitosterol ��-D-glucoside biological activity immunohistochemical and NT 157 site Histopathologic ExperimentsFor the immunohistochemical evaluation, two mice per group were randomly selected 4 days after viral administration. Under aseptic conditions, the tumor tissues were harvested and cut into pieces of approximately 1 cubic millimeter in size. The fresh tissuePotent Antitumor Effect of Ad(ST13)*CEA*E1A(D24)Figure 3. Morphological changes and apoptosis detected by flow cytometry. A. Morphological observations of tumor cells and normal cells infected with the various oncolytic adenoviruses as detected by microscopy. Cells were infected at an MOI of 10, and the morphological changes in the cells were observed by microscopy after 72 hours of infection. B. Detection of apoptosis in SW620 cells by FACS. SW620 cells were infected with either ONYX-015, Ad?(EGFP)?CEA?E1A(D24) or Ad?(ST13)?CEA?E1A(D24) at an MOI of 10. At 48 hours, the cells were harvested and stained with annexin V-FITC (for early-stage apoptosis) or PI (for late-stage apoptosis) and w.Umor cells infected with different MOIs of Ad?(ST13)?CEA?E1A(D24). CEAnegative colon cancer cell line (Colo-320) and CEA-positive non-colon cancer cell line (A549, MCF-7) were infected with Ad?(ST13)?CEA?E1A(D24) at a range of MOIs (0.1, 1, 5 or 10 MOI), 3 days, cell viability was determined using an MTT assay. Bars represent the means 6 SD (n = 6). doi:10.1371/journal.pone.0047566.gexperimental procedures were approved by the Institutional Animal Care and Use Committee of Shanghai Institute of Biochemistry and Cell Biology under protocol IBCB-SPF0029. Xenografted mice were used as a model system to study the cytotoxic effects of SW620 cells (Chinese Academy of Sciences, Shanghai, China) in vivo. SW620 cells (56106/100 mL) were injected subcutaneously into the lower right flank of female nude mice to establish the tumor xenograft model. The tumor volume (V), which was based on caliper measurements, was calculated using the formula V (mm3) = length (mm)6width (mm) 2/2. After the tumors reached 100 to 130 mm3 in size, the mice were randomly divided into control and treatment groups (n = 8). The treatment groups were administrated intratumorally at the consecutive daily doses of 56108 plaque-forming units (PFU)/ 100 mL of either ONYX-015, Ad?(EGFP)?CEA?E1A(D24), Ad (ST13)?CEA?E1A(D24) for four days. The control group was treated with consecutive intratumoral injections four times with the same volume of PBS.was immediately immersed into 4 paraformaldehyde, where it was kept 25837696 for 48 h at room temperature and then embedded into paraffin. Afterward, the samples were cut into 4-mm-thick sections. Immunohistochemistry was performed with an anti-adenoviral hexon or anti-ST13 antibody (Biodesign International, Saco, ME) using an immunohistochemistry kit according to the manufacturer’s protocol. In addition, pathological changes in the tumor tissue were examined after hematoxylin and eosin (H E) staining and TUNEL staining as well as by transmission electric microscopy (TEM).Statistical AnalysisAll data are presented as the mean 6 SD and were processed using the SPSS 10.1 statistical software. Each quantitative experiment was carried out at least three times, and statistical significance was assigned for P values #0.05.Results Construction and Characterization of Ad?(ST13)?CEA?E1A(D24)The Ad?(ST13)?CEA?E1A(D24) vector was successfully constructed by replacing the native E1A promoter with the colorectal cancer-specific CEA promoter, deleting 24 bp in Ad?E1A (923?Immunohistochemical and Histopathologic ExperimentsFor the immunohistochemical evaluation, two mice per group were randomly selected 4 days after viral administration. Under aseptic conditions, the tumor tissues were harvested and cut into pieces of approximately 1 cubic millimeter in size. The fresh tissuePotent Antitumor Effect of Ad(ST13)*CEA*E1A(D24)Figure 3. Morphological changes and apoptosis detected by flow cytometry. A. Morphological observations of tumor cells and normal cells infected with the various oncolytic adenoviruses as detected by microscopy. Cells were infected at an MOI of 10, and the morphological changes in the cells were observed by microscopy after 72 hours of infection. B. Detection of apoptosis in SW620 cells by FACS. SW620 cells were infected with either ONYX-015, Ad?(EGFP)?CEA?E1A(D24) or Ad?(ST13)?CEA?E1A(D24) at an MOI of 10. At 48 hours, the cells were harvested and stained with annexin V-FITC (for early-stage apoptosis) or PI (for late-stage apoptosis) and w.