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Assessment of bystander killing-mediated therapy of malignant brain tumors using a multimodal imaging approach.

Leten C, Trekker J, Struys T, Dresselaers T, Gijsbers R, Vande Velde G, Lambrichts I, Van Der Linden A, Verfaillie CM, Himmelreich U - Stem Cell Res Ther (2015)

Bottom Line: Subsequently, ganciclovir (GCV) treatment was commenced and the fate of both the MAPCs and the tumor were followed by multimodal imaging (MRI and bioluminescence imaging).Noteworthy, in some phosphate-buffered saline-treated animals (33 %), a significant decrease in tumor size was seen compared to sham-operated animals, which could potentially also be caused by a synergistic effect of the immune-modulatory stem cells.This treatment could be followed and guided noninvasively in vivo by MRI and bioluminescence imaging.

View Article: PubMed Central - PubMed

Affiliation: Biomedical MRI, Department of Imaging and Pathology, KU Leuven, 3000, Leuven, Belgium. cindy.leten@gmail.com.

ABSTRACT

Introduction: In this study, we planned to assess if adult stem cell-based suicide gene therapy can efficiently eliminate glioblastoma cells in vivo. We investigated the therapeutic potential of mouse Oct4(-) bone marrow multipotent adult progenitor cells (mOct4(-) BM-MAPCs) in a mouse glioblastoma model, guided by multimodal in vivo imaging methods to identify therapeutic windows.

Methods: Magnetic resonance imaging (MRI) of animals, wherein 5 × 10(5) syngeneic enhanced green fluorescent protein-firefly luciferase-herpes simplex virus thymidine kinase (eGFP-fLuc-HSV-TK) expressing and superparamagnetic iron oxide nanoparticle labeled (1 % or 10 %) mOct4(-) BM-MAPCs were grafted in glioblastoma (GL261)-bearing animals, showed that labeled mOct4(-) BM-MAPCs were located in and in close proximity to the tumor. Subsequently, ganciclovir (GCV) treatment was commenced and the fate of both the MAPCs and the tumor were followed by multimodal imaging (MRI and bioluminescence imaging).

Results: In the majority of GCV-treated, but not phosphate-buffered saline-treated animals, a significant difference was found in mOct4(-) BM-MAPC viability and tumor size at the end of treatment. Noteworthy, in some phosphate-buffered saline-treated animals (33 %), a significant decrease in tumor size was seen compared to sham-operated animals, which could potentially also be caused by a synergistic effect of the immune-modulatory stem cells.

Conclusions: Suicide gene therapy using mOct4(-) BM-MAPCs as cellular carriers was effective in reducing the tumor size in the majority of the GCV-treated animals leading to a longer progression-free survival compared to sham-operated animals. This treatment could be followed and guided noninvasively in vivo by MRI and bioluminescence imaging. Noninvasive imaging is of particular interest for a rapid and efficient validation of stem cell-based therapeutic approaches for glioblastoma and hereby contributes to a better understanding and optimization of a promising therapeutic approach for glioblastoma patients.

No MeSH data available.


Related in: MedlinePlus

Histological analysis of representative animals at the end of treatment. Animals were sacrificed at the end of treatment and brain sections were stained using Massson’s Trichrome staining (top) for overall histological assessment, Iba1 staining (middle) for assessment of macrophage activation inside and surrounding the tumor, and Prussian blue staining (bottom) as an iron staining of brain sections from all different treatment groups, including examples from responding and nonresponding animals. See Additional file 1 (Figure S1) for further high-magnification images and a more elaborate explanation regarding the observations made based on these staining. GCV ganciclovir, PBS phosphate-buffered saline, SHAM sham-operated
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Fig6: Histological analysis of representative animals at the end of treatment. Animals were sacrificed at the end of treatment and brain sections were stained using Massson’s Trichrome staining (top) for overall histological assessment, Iba1 staining (middle) for assessment of macrophage activation inside and surrounding the tumor, and Prussian blue staining (bottom) as an iron staining of brain sections from all different treatment groups, including examples from responding and nonresponding animals. See Additional file 1 (Figure S1) for further high-magnification images and a more elaborate explanation regarding the observations made based on these staining. GCV ganciclovir, PBS phosphate-buffered saline, SHAM sham-operated

Mentions: A number of animals were observed long term to determine progression-free survival (Fig. 5). Progression-free survival curves generated for sham-operated animals (n = 3) and PBS-treated animals (n = 6) were comparable. From the GCV-treated animals, some (n = 3) did not respond to treatment and showed a similar survival to the sham-operated and PBS-treated animals. However, some GCV-treated (n = 4) and one animal treated with PBS displayed a longer progression-free survival, with two animals of the GCV-treated group surviving long term (184 days) without any signs of tumor re-growth (Fig. 5a). The median progression-free survival of sham-operated animals (35 days) was significantly lower compared to GCV responding animals (119.5 days) (p = 0.0101). Furthermore, histological analysis was performed to confirm the data obtained in vivo. Masson’s trichrome staining showed the presence of large blood vessels explaining the hypointense signal in large tumors. Prussian blue staining confirmed the presence of ihSPIO particles in and around the tumor most likely due to the engrafted mOct4−BM-MAPCs. In small lesions, as seen in the therapy responders, iron staining was more concentrated around the injection site in comparison to large tumors as seen in nonresponders. Finally, Iba I staining for the presence of activated microglia was performed which showed remarkably few activated microglial cells inside the tumor, although microglial activation was more pronounced surrounding the tumor (Fig. 6 and Additional file 1: Figure S1). Quantitative comparison between the different groups based on Iba I staining was difficult due to the reduced lesion size in responding animals and apparently higher cell densities (Additional file 1: Figure S1).Fig. 5


Assessment of bystander killing-mediated therapy of malignant brain tumors using a multimodal imaging approach.

Leten C, Trekker J, Struys T, Dresselaers T, Gijsbers R, Vande Velde G, Lambrichts I, Van Der Linden A, Verfaillie CM, Himmelreich U - Stem Cell Res Ther (2015)

Histological analysis of representative animals at the end of treatment. Animals were sacrificed at the end of treatment and brain sections were stained using Massson’s Trichrome staining (top) for overall histological assessment, Iba1 staining (middle) for assessment of macrophage activation inside and surrounding the tumor, and Prussian blue staining (bottom) as an iron staining of brain sections from all different treatment groups, including examples from responding and nonresponding animals. See Additional file 1 (Figure S1) for further high-magnification images and a more elaborate explanation regarding the observations made based on these staining. GCV ganciclovir, PBS phosphate-buffered saline, SHAM sham-operated
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4562202&req=5

Fig6: Histological analysis of representative animals at the end of treatment. Animals were sacrificed at the end of treatment and brain sections were stained using Massson’s Trichrome staining (top) for overall histological assessment, Iba1 staining (middle) for assessment of macrophage activation inside and surrounding the tumor, and Prussian blue staining (bottom) as an iron staining of brain sections from all different treatment groups, including examples from responding and nonresponding animals. See Additional file 1 (Figure S1) for further high-magnification images and a more elaborate explanation regarding the observations made based on these staining. GCV ganciclovir, PBS phosphate-buffered saline, SHAM sham-operated
Mentions: A number of animals were observed long term to determine progression-free survival (Fig. 5). Progression-free survival curves generated for sham-operated animals (n = 3) and PBS-treated animals (n = 6) were comparable. From the GCV-treated animals, some (n = 3) did not respond to treatment and showed a similar survival to the sham-operated and PBS-treated animals. However, some GCV-treated (n = 4) and one animal treated with PBS displayed a longer progression-free survival, with two animals of the GCV-treated group surviving long term (184 days) without any signs of tumor re-growth (Fig. 5a). The median progression-free survival of sham-operated animals (35 days) was significantly lower compared to GCV responding animals (119.5 days) (p = 0.0101). Furthermore, histological analysis was performed to confirm the data obtained in vivo. Masson’s trichrome staining showed the presence of large blood vessels explaining the hypointense signal in large tumors. Prussian blue staining confirmed the presence of ihSPIO particles in and around the tumor most likely due to the engrafted mOct4−BM-MAPCs. In small lesions, as seen in the therapy responders, iron staining was more concentrated around the injection site in comparison to large tumors as seen in nonresponders. Finally, Iba I staining for the presence of activated microglia was performed which showed remarkably few activated microglial cells inside the tumor, although microglial activation was more pronounced surrounding the tumor (Fig. 6 and Additional file 1: Figure S1). Quantitative comparison between the different groups based on Iba I staining was difficult due to the reduced lesion size in responding animals and apparently higher cell densities (Additional file 1: Figure S1).Fig. 5

Bottom Line: Subsequently, ganciclovir (GCV) treatment was commenced and the fate of both the MAPCs and the tumor were followed by multimodal imaging (MRI and bioluminescence imaging).Noteworthy, in some phosphate-buffered saline-treated animals (33 %), a significant decrease in tumor size was seen compared to sham-operated animals, which could potentially also be caused by a synergistic effect of the immune-modulatory stem cells.This treatment could be followed and guided noninvasively in vivo by MRI and bioluminescence imaging.

View Article: PubMed Central - PubMed

Affiliation: Biomedical MRI, Department of Imaging and Pathology, KU Leuven, 3000, Leuven, Belgium. cindy.leten@gmail.com.

ABSTRACT

Introduction: In this study, we planned to assess if adult stem cell-based suicide gene therapy can efficiently eliminate glioblastoma cells in vivo. We investigated the therapeutic potential of mouse Oct4(-) bone marrow multipotent adult progenitor cells (mOct4(-) BM-MAPCs) in a mouse glioblastoma model, guided by multimodal in vivo imaging methods to identify therapeutic windows.

Methods: Magnetic resonance imaging (MRI) of animals, wherein 5 × 10(5) syngeneic enhanced green fluorescent protein-firefly luciferase-herpes simplex virus thymidine kinase (eGFP-fLuc-HSV-TK) expressing and superparamagnetic iron oxide nanoparticle labeled (1 % or 10 %) mOct4(-) BM-MAPCs were grafted in glioblastoma (GL261)-bearing animals, showed that labeled mOct4(-) BM-MAPCs were located in and in close proximity to the tumor. Subsequently, ganciclovir (GCV) treatment was commenced and the fate of both the MAPCs and the tumor were followed by multimodal imaging (MRI and bioluminescence imaging).

Results: In the majority of GCV-treated, but not phosphate-buffered saline-treated animals, a significant difference was found in mOct4(-) BM-MAPC viability and tumor size at the end of treatment. Noteworthy, in some phosphate-buffered saline-treated animals (33 %), a significant decrease in tumor size was seen compared to sham-operated animals, which could potentially also be caused by a synergistic effect of the immune-modulatory stem cells.

Conclusions: Suicide gene therapy using mOct4(-) BM-MAPCs as cellular carriers was effective in reducing the tumor size in the majority of the GCV-treated animals leading to a longer progression-free survival compared to sham-operated animals. This treatment could be followed and guided noninvasively in vivo by MRI and bioluminescence imaging. Noninvasive imaging is of particular interest for a rapid and efficient validation of stem cell-based therapeutic approaches for glioblastoma and hereby contributes to a better understanding and optimization of a promising therapeutic approach for glioblastoma patients.

No MeSH data available.


Related in: MedlinePlus