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The engineered Salmonella typhimurium inhibits tumorigenesis in advanced glioma.

Chen JQ, Zhan YF, Wang W, Jiang SN, Li XY - Onco Targets Ther (2015)

Bottom Line: The differences between the three groups in tumor volume and survival time were analyzed.MRI showed that the tumor volume in the S. typhimurium with ClyA group were significantly reduced compared to the bacteria alone and no bacteria groups 7 days post-doxycycline treatment (P<0.05), while the necrotic tumor volume in the S. typhimurium with ClyA group and S. typhimurium alone group increased significantly compared to the control group (P<0.01).In addition, the survival time was significantly prolonged in the bacteria-treated group compared to the PBS-treated control group (P<0.01).

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, The Third Xiangya Hospital, Central South University, Changsha, People's Republic of China.

ABSTRACT

Objective: To explore the antitumor role of the attenuated Salmonella typhimurium ΔppGpp with inducible cytolysin A (ClyA) in advanced stage of glioma.

Materials and methods: The C6 rat glioma cells were orthotopically implanted by surgery into the caudate nucleus of rat brains. The rats were then randomly divided into the treatment group (SL + ClyA) (n=12), negative control group (SL) (n=12), and control group (phosphate-buffered saline [PBS]) (n=12). In the treatment group, the attenuated S. typhimurium were transformed with the plasmid-encoded antitumor gene ClyA. The expression of ClyA was controlled by the TetR-regulated promoter in response to extracellular doxycycline. The plasmid also contained an imaging gene lux to allow illumination of the tumor infected by the bacteria. The rat glioma C6 cells were implanted into the caudate nucleus of all rats. The engineered S. typhimurium and respective controls were injected intravenously into the rats 21 days after initial tumor implantation. The pathological analysis of the glioma tumor was performed at 21 days and 28 days (7 days after doxycycline treatment) postimplantation. All rats underwent MRI (magnetic resonance imaging) and bioluminescence study at 21 days and 28 days postimplantation to detect tumor volume. The differences between the three groups in tumor volume and survival time were analyzed.

Results: Advanced stage glioma was detected at 21 days postimplantation. Bioluminescence showed that the engineered S. typhimurium accumulated in glioma tumors and disappeared in the normal reticuloendothelial tissues 3 days after intravenous injection. MRI showed that the tumor volume in the S. typhimurium with ClyA group were significantly reduced compared to the bacteria alone and no bacteria groups 7 days post-doxycycline treatment (P<0.05), while the necrotic tumor volume in the S. typhimurium with ClyA group and S. typhimurium alone group increased significantly compared to the control group (P<0.01). In addition, the survival time was significantly prolonged in the bacteria-treated group compared to the PBS-treated control group (P<0.01).

Conclusion: The engineered S. typhimurium can significantly induce cancer cell apoptosis in the tumor center and inhibit cancer cell proliferation in the outer zone of advanced glioma tumor, leading to a prolonged survival time in rats. In addition, the engineered S. typhimurium that carried the antitumor and imaging genes controlled by the TetR-regulated promoter have high delivery efficiency with tolerable side effects in rats.

No MeSH data available.


Related in: MedlinePlus

Engineered Salmonella typhimurium has antitumor roles in both tumor core and outer proliferative zone.Notes: (A) H&E staining of the glioma infected by the engineered S. typhimurium 28 days postimplantation. The black box included the border area of the necrotic tumor core and the proliferative zone in the SL + ClyA group. (B) A merged image of the immunofluorescent staining of the tissue from the black box (A) with (C) antisalmonella antibody (green), (D) anti-ClyA antibody (red), and (E) DAPI/Antifade (blue). Scale bar =100 μm.Abbreviations: H&E, hematoxylin–eosin; SL, treatment group; ClyA, cytolysin A; DAPI, 4′,6-diamidino-2-phenylindole.
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f4-ott-8-2555: Engineered Salmonella typhimurium has antitumor roles in both tumor core and outer proliferative zone.Notes: (A) H&E staining of the glioma infected by the engineered S. typhimurium 28 days postimplantation. The black box included the border area of the necrotic tumor core and the proliferative zone in the SL + ClyA group. (B) A merged image of the immunofluorescent staining of the tissue from the black box (A) with (C) antisalmonella antibody (green), (D) anti-ClyA antibody (red), and (E) DAPI/Antifade (blue). Scale bar =100 μm.Abbreviations: H&E, hematoxylin–eosin; SL, treatment group; ClyA, cytolysin A; DAPI, 4′,6-diamidino-2-phenylindole.

Mentions: Histopathological studies showed that the engineered S. typhimurium induced large area of necrosis in the tumor center 28 days postimplantation (Figure 4A). Interestingly, immunofluorescence staining revealed that the engineered S. typhimurium mainly accumulated in the necrotic zones of glioma. However, the ClyA protein was detected in the outer proliferative layer of the tumor (Figure 4B–E), suggesting that S. typhimurium bacteria had its antitumor function in the tumor core while the ClyA protein secreted by the engineered S. typhimurium can penetrate into the proliferative zone to inhibit tumor growth.


The engineered Salmonella typhimurium inhibits tumorigenesis in advanced glioma.

Chen JQ, Zhan YF, Wang W, Jiang SN, Li XY - Onco Targets Ther (2015)

Engineered Salmonella typhimurium has antitumor roles in both tumor core and outer proliferative zone.Notes: (A) H&E staining of the glioma infected by the engineered S. typhimurium 28 days postimplantation. The black box included the border area of the necrotic tumor core and the proliferative zone in the SL + ClyA group. (B) A merged image of the immunofluorescent staining of the tissue from the black box (A) with (C) antisalmonella antibody (green), (D) anti-ClyA antibody (red), and (E) DAPI/Antifade (blue). Scale bar =100 μm.Abbreviations: H&E, hematoxylin–eosin; SL, treatment group; ClyA, cytolysin A; DAPI, 4′,6-diamidino-2-phenylindole.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4592054&req=5

f4-ott-8-2555: Engineered Salmonella typhimurium has antitumor roles in both tumor core and outer proliferative zone.Notes: (A) H&E staining of the glioma infected by the engineered S. typhimurium 28 days postimplantation. The black box included the border area of the necrotic tumor core and the proliferative zone in the SL + ClyA group. (B) A merged image of the immunofluorescent staining of the tissue from the black box (A) with (C) antisalmonella antibody (green), (D) anti-ClyA antibody (red), and (E) DAPI/Antifade (blue). Scale bar =100 μm.Abbreviations: H&E, hematoxylin–eosin; SL, treatment group; ClyA, cytolysin A; DAPI, 4′,6-diamidino-2-phenylindole.
Mentions: Histopathological studies showed that the engineered S. typhimurium induced large area of necrosis in the tumor center 28 days postimplantation (Figure 4A). Interestingly, immunofluorescence staining revealed that the engineered S. typhimurium mainly accumulated in the necrotic zones of glioma. However, the ClyA protein was detected in the outer proliferative layer of the tumor (Figure 4B–E), suggesting that S. typhimurium bacteria had its antitumor function in the tumor core while the ClyA protein secreted by the engineered S. typhimurium can penetrate into the proliferative zone to inhibit tumor growth.

Bottom Line: The differences between the three groups in tumor volume and survival time were analyzed.MRI showed that the tumor volume in the S. typhimurium with ClyA group were significantly reduced compared to the bacteria alone and no bacteria groups 7 days post-doxycycline treatment (P<0.05), while the necrotic tumor volume in the S. typhimurium with ClyA group and S. typhimurium alone group increased significantly compared to the control group (P<0.01).In addition, the survival time was significantly prolonged in the bacteria-treated group compared to the PBS-treated control group (P<0.01).

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, The Third Xiangya Hospital, Central South University, Changsha, People's Republic of China.

ABSTRACT

Objective: To explore the antitumor role of the attenuated Salmonella typhimurium ΔppGpp with inducible cytolysin A (ClyA) in advanced stage of glioma.

Materials and methods: The C6 rat glioma cells were orthotopically implanted by surgery into the caudate nucleus of rat brains. The rats were then randomly divided into the treatment group (SL + ClyA) (n=12), negative control group (SL) (n=12), and control group (phosphate-buffered saline [PBS]) (n=12). In the treatment group, the attenuated S. typhimurium were transformed with the plasmid-encoded antitumor gene ClyA. The expression of ClyA was controlled by the TetR-regulated promoter in response to extracellular doxycycline. The plasmid also contained an imaging gene lux to allow illumination of the tumor infected by the bacteria. The rat glioma C6 cells were implanted into the caudate nucleus of all rats. The engineered S. typhimurium and respective controls were injected intravenously into the rats 21 days after initial tumor implantation. The pathological analysis of the glioma tumor was performed at 21 days and 28 days (7 days after doxycycline treatment) postimplantation. All rats underwent MRI (magnetic resonance imaging) and bioluminescence study at 21 days and 28 days postimplantation to detect tumor volume. The differences between the three groups in tumor volume and survival time were analyzed.

Results: Advanced stage glioma was detected at 21 days postimplantation. Bioluminescence showed that the engineered S. typhimurium accumulated in glioma tumors and disappeared in the normal reticuloendothelial tissues 3 days after intravenous injection. MRI showed that the tumor volume in the S. typhimurium with ClyA group were significantly reduced compared to the bacteria alone and no bacteria groups 7 days post-doxycycline treatment (P<0.05), while the necrotic tumor volume in the S. typhimurium with ClyA group and S. typhimurium alone group increased significantly compared to the control group (P<0.01). In addition, the survival time was significantly prolonged in the bacteria-treated group compared to the PBS-treated control group (P<0.01).

Conclusion: The engineered S. typhimurium can significantly induce cancer cell apoptosis in the tumor center and inhibit cancer cell proliferation in the outer zone of advanced glioma tumor, leading to a prolonged survival time in rats. In addition, the engineered S. typhimurium that carried the antitumor and imaging genes controlled by the TetR-regulated promoter have high delivery efficiency with tolerable side effects in rats.

No MeSH data available.


Related in: MedlinePlus