Limits...
In tumors Salmonella migrate away from vasculature toward the transition zone and induce apoptosis.

Ganai S, Arenas RB, Sauer JP, Bentley B, Forbes NS - Cancer Gene Ther. (2011)

Bottom Line: From 12 and 48 h after injection, the average distance between bacterial colonies and functional vasculature significantly increased from 130 to 310 μm.All observed metastases contained Salmonella and the extent of bacterial colocalization with metastatic tissue was 44% compared with 0.5% with normal liver parenchyma.These results demonstrate that Salmonella can penetrate tumor tissue and can selectively target metastases, two critical characteristics of a targeted cancer therapeutic.

View Article: PubMed Central - PubMed

Affiliation: Department of Surgery, Baystate Medical Center, Tufts University School of Medicine, Springfield, MA, USA.

ABSTRACT
Motile bacteria can overcome diffusion resistances that substantially reduce the efficacy of standard cancer therapies. Many reports have also recently described the ability of Salmonella to deliver therapeutic molecules to tumors. Despite this potential, little is known about the spatiotemporal dynamics of bacterial accumulation in solid tumors. Ultimately this timing will affect how these microbes are used therapeutically. To determine how bacteria localize, we intravenously injected Salmonella typhimurium into BALB/c mice with 4T1 mammary carcinoma and measured the average bacterial content as a function of time. Immunohistochemistry was used to measure the extent of apoptosis, the average distance of bacteria from tumor vasculature and the location of bacteria in four different regions: the core, transition, body and edge. Bacteria accumulation was also measured in pulmonary and hepatic metastases. The doubling time of bacterial colonies in tumors was measured to be 16.8 h, and colonization was determined to delay tumor growth by 48 h. From 12 and 48 h after injection, the average distance between bacterial colonies and functional vasculature significantly increased from 130 to 310 μm. After 48 h, bacteria migrated away from the tumor edge toward the central core and induced apoptosis. After 96 h, bacteria began to marginate to the tumor transition zone. All observed metastases contained Salmonella and the extent of bacterial colocalization with metastatic tissue was 44% compared with 0.5% with normal liver parenchyma. These results demonstrate that Salmonella can penetrate tumor tissue and can selectively target metastases, two critical characteristics of a targeted cancer therapeutic.

Show MeSH

Related in: MedlinePlus

Bacterial accumulation migrated away from vessels with timeA, The location of Salmonella colonies (white arrow, red stain) and perfused blood vessels (black arrow, brown stain) were identified using dual label immunohistochemistry (upper left). The location of vessels was captured from the blue component of the image (upper right) and used to generate a Euclidian distance map (lower left). Merged distance maps identified the location of bacterial colonies relative to the nearest functional vessel (lower right). The mean distance between the colonies and perfused vasculature in this example image is 185.9 ± 67.6 (SD) μm. The scale bar is 25μm. B, The mean distance between bacteria and vasculature increased for 48hrs after injection. The distances at 12 and 48 hrs were greater than zero (*, p<0.05) and increased between 12 and 48hrs (†, p<0.0001). Thirty images were examined per tumor. C, Maximum distance of bacteria from vasculature as a function of time, grouped by region. At 12 hours, the maximum distance was greater in the core compared to the edge (*, p<0.05). The maximum distance in the edge increased from 12 to 48 hours (*, p<0.01). For clarity, error bars are only displayed for the edge and core regions.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3117926&req=5

Figure 4: Bacterial accumulation migrated away from vessels with timeA, The location of Salmonella colonies (white arrow, red stain) and perfused blood vessels (black arrow, brown stain) were identified using dual label immunohistochemistry (upper left). The location of vessels was captured from the blue component of the image (upper right) and used to generate a Euclidian distance map (lower left). Merged distance maps identified the location of bacterial colonies relative to the nearest functional vessel (lower right). The mean distance between the colonies and perfused vasculature in this example image is 185.9 ± 67.6 (SD) μm. The scale bar is 25μm. B, The mean distance between bacteria and vasculature increased for 48hrs after injection. The distances at 12 and 48 hrs were greater than zero (*, p<0.05) and increased between 12 and 48hrs (†, p<0.0001). Thirty images were examined per tumor. C, Maximum distance of bacteria from vasculature as a function of time, grouped by region. At 12 hours, the maximum distance was greater in the core compared to the edge (*, p<0.05). The maximum distance in the edge increased from 12 to 48 hours (*, p<0.01). For clarity, error bars are only displayed for the edge and core regions.

Mentions: Dual labeled immunohistochemistry was used to determine bacterial localization relative to tumor vasculature (Figure 4A). In thirty images per tumor, the location of bacterial colonies (stained red, white arrow) and functional vasculature (stained brown, black arrow) were concurrently identified (Figure 4A, upper left) and translated into binary images (Figure 4A, upper right). Euclidean distance maps (Figure 4A, lower left) were combined with bacterial binary images to determine the distance of each bacterial colony to the nearest blood vessel (Figure 4A, lower right). In all treated tumors the mean distance between bacteria and vasculature increased from 128.5μm (95% CI, 92.1 – 164.9μm) to 309.0μm (95% CI, 262.0 – 356.0μm) from 12 to 48 hours (p<0.05), followed by a downward inflection at 96 hours (Figure 4B). From these values, bacterial velocity through tumors for the first 48 hours was 6.1 μm/h (95% CI, 4.8 – 7.4 μm/h), which is considerably slower than the linear velocity of motile bacteria in culture medium (20–50μm/s). The average distance at all three time points was significantly greater than zero (p<0.05), suggesting migration from vessels into tumor tissue.


In tumors Salmonella migrate away from vasculature toward the transition zone and induce apoptosis.

Ganai S, Arenas RB, Sauer JP, Bentley B, Forbes NS - Cancer Gene Ther. (2011)

Bacterial accumulation migrated away from vessels with timeA, The location of Salmonella colonies (white arrow, red stain) and perfused blood vessels (black arrow, brown stain) were identified using dual label immunohistochemistry (upper left). The location of vessels was captured from the blue component of the image (upper right) and used to generate a Euclidian distance map (lower left). Merged distance maps identified the location of bacterial colonies relative to the nearest functional vessel (lower right). The mean distance between the colonies and perfused vasculature in this example image is 185.9 ± 67.6 (SD) μm. The scale bar is 25μm. B, The mean distance between bacteria and vasculature increased for 48hrs after injection. The distances at 12 and 48 hrs were greater than zero (*, p<0.05) and increased between 12 and 48hrs (†, p<0.0001). Thirty images were examined per tumor. C, Maximum distance of bacteria from vasculature as a function of time, grouped by region. At 12 hours, the maximum distance was greater in the core compared to the edge (*, p<0.05). The maximum distance in the edge increased from 12 to 48 hours (*, p<0.01). For clarity, error bars are only displayed for the edge and core regions.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3117926&req=5

Figure 4: Bacterial accumulation migrated away from vessels with timeA, The location of Salmonella colonies (white arrow, red stain) and perfused blood vessels (black arrow, brown stain) were identified using dual label immunohistochemistry (upper left). The location of vessels was captured from the blue component of the image (upper right) and used to generate a Euclidian distance map (lower left). Merged distance maps identified the location of bacterial colonies relative to the nearest functional vessel (lower right). The mean distance between the colonies and perfused vasculature in this example image is 185.9 ± 67.6 (SD) μm. The scale bar is 25μm. B, The mean distance between bacteria and vasculature increased for 48hrs after injection. The distances at 12 and 48 hrs were greater than zero (*, p<0.05) and increased between 12 and 48hrs (†, p<0.0001). Thirty images were examined per tumor. C, Maximum distance of bacteria from vasculature as a function of time, grouped by region. At 12 hours, the maximum distance was greater in the core compared to the edge (*, p<0.05). The maximum distance in the edge increased from 12 to 48 hours (*, p<0.01). For clarity, error bars are only displayed for the edge and core regions.
Mentions: Dual labeled immunohistochemistry was used to determine bacterial localization relative to tumor vasculature (Figure 4A). In thirty images per tumor, the location of bacterial colonies (stained red, white arrow) and functional vasculature (stained brown, black arrow) were concurrently identified (Figure 4A, upper left) and translated into binary images (Figure 4A, upper right). Euclidean distance maps (Figure 4A, lower left) were combined with bacterial binary images to determine the distance of each bacterial colony to the nearest blood vessel (Figure 4A, lower right). In all treated tumors the mean distance between bacteria and vasculature increased from 128.5μm (95% CI, 92.1 – 164.9μm) to 309.0μm (95% CI, 262.0 – 356.0μm) from 12 to 48 hours (p<0.05), followed by a downward inflection at 96 hours (Figure 4B). From these values, bacterial velocity through tumors for the first 48 hours was 6.1 μm/h (95% CI, 4.8 – 7.4 μm/h), which is considerably slower than the linear velocity of motile bacteria in culture medium (20–50μm/s). The average distance at all three time points was significantly greater than zero (p<0.05), suggesting migration from vessels into tumor tissue.

Bottom Line: From 12 and 48 h after injection, the average distance between bacterial colonies and functional vasculature significantly increased from 130 to 310 μm.All observed metastases contained Salmonella and the extent of bacterial colocalization with metastatic tissue was 44% compared with 0.5% with normal liver parenchyma.These results demonstrate that Salmonella can penetrate tumor tissue and can selectively target metastases, two critical characteristics of a targeted cancer therapeutic.

View Article: PubMed Central - PubMed

Affiliation: Department of Surgery, Baystate Medical Center, Tufts University School of Medicine, Springfield, MA, USA.

ABSTRACT
Motile bacteria can overcome diffusion resistances that substantially reduce the efficacy of standard cancer therapies. Many reports have also recently described the ability of Salmonella to deliver therapeutic molecules to tumors. Despite this potential, little is known about the spatiotemporal dynamics of bacterial accumulation in solid tumors. Ultimately this timing will affect how these microbes are used therapeutically. To determine how bacteria localize, we intravenously injected Salmonella typhimurium into BALB/c mice with 4T1 mammary carcinoma and measured the average bacterial content as a function of time. Immunohistochemistry was used to measure the extent of apoptosis, the average distance of bacteria from tumor vasculature and the location of bacteria in four different regions: the core, transition, body and edge. Bacteria accumulation was also measured in pulmonary and hepatic metastases. The doubling time of bacterial colonies in tumors was measured to be 16.8 h, and colonization was determined to delay tumor growth by 48 h. From 12 and 48 h after injection, the average distance between bacterial colonies and functional vasculature significantly increased from 130 to 310 μm. After 48 h, bacteria migrated away from the tumor edge toward the central core and induced apoptosis. After 96 h, bacteria began to marginate to the tumor transition zone. All observed metastases contained Salmonella and the extent of bacterial colocalization with metastatic tissue was 44% compared with 0.5% with normal liver parenchyma. These results demonstrate that Salmonella can penetrate tumor tissue and can selectively target metastases, two critical characteristics of a targeted cancer therapeutic.

Show MeSH
Related in: MedlinePlus