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Pinhole micro-SPECT/CT for noninvasive monitoring and quantitation of oncolytic virus dispersion and percent infection in solid tumors.

Penheiter AR, Griesmann GE, Federspiel MJ, Dingli D, Russell SJ, Carlson SK - Gene Ther. (2011)

Bottom Line: The purpose of our study was to validate the ability of pinhole micro-single-photon emission computed tomography/computed tomography (SPECT/CT) to: 1) accurately resolve the intratumoral dispersion pattern and 2) quantify the infection percentage in solid tumors of an oncolytic measles virus encoding the human sodium iodide symporter (MV-NIS).We reliably resolved multiple distinct intratumoral zones of infection from non-infected regions.Pinhole micro-SPECT/CT imaging using the NIS reporter demonstrated precise localization and quantitation of oncolytic MV-NIS infection, and can replace more time-consuming and expensive analyses (for example, autoradiography and IHC) that require animal killing.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Medicine, Mayo Clinic, Rochester, MN 55905, USA.

ABSTRACT
The purpose of our study was to validate the ability of pinhole micro-single-photon emission computed tomography/computed tomography (SPECT/CT) to: 1) accurately resolve the intratumoral dispersion pattern and 2) quantify the infection percentage in solid tumors of an oncolytic measles virus encoding the human sodium iodide symporter (MV-NIS). Sodium iodide symporter (NIS) RNA level and dispersion pattern were determined in control and MV-NIS-infected BxPC-3 pancreatic tumor cells and mouse xenografts using quantitative, real-time, reverse transcriptase, polymerase chain reaction, autoradiography and immunohistochemistry (IHC). Mice with BxPC-3 xenografts were imaged with (123)I or (99)TcO(4) micro-SPECT/CT. Tumor dimensions and radionuclide localization were determined with imaging software. Linear regression and correlation analyses were performed to determine the relationship between tumor infection percentage and radionuclide uptake (% injected dose per gram) above background and a highly significant correlation was observed (r(2)=0.947). A detection threshold of 1.5-fold above the control tumor uptake (background) yielded a sensitivity of 2.7% MV-NIS-infected tumor cells. We reliably resolved multiple distinct intratumoral zones of infection from non-infected regions. Pinhole micro-SPECT/CT imaging using the NIS reporter demonstrated precise localization and quantitation of oncolytic MV-NIS infection, and can replace more time-consuming and expensive analyses (for example, autoradiography and IHC) that require animal killing.

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Determination of Tumor Cell and Stroma Percentages within a Human Pancreatic Cancer Xenograft. Hematoxylin-stained, frozen sections (original magnification, ×200) were analyzed to determine the percentage of tumor occupied by BxPC-3 cells in 5 MV-NIS-infected and 3 uninfected control tumors. The rectangle represents a known area, and regions of interest (ie, stroma [fibroblasts, collagen, etc]) were outlined manually for image analysis.
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Figure 2: Determination of Tumor Cell and Stroma Percentages within a Human Pancreatic Cancer Xenograft. Hematoxylin-stained, frozen sections (original magnification, ×200) were analyzed to determine the percentage of tumor occupied by BxPC-3 cells in 5 MV-NIS-infected and 3 uninfected control tumors. The rectangle represents a known area, and regions of interest (ie, stroma [fibroblasts, collagen, etc]) were outlined manually for image analysis.

Mentions: Because MV-NIS infects only human tumor cells and not mouse stromal cells, any volume-based method of infection quantitation requires an estimate of the tumor volume occupied by tumor cells (versus stroma). First, we manually determined the percentage of tumor occupied by BxPC-3 cancer cells and by stroma by using region-of-interest image analysis on hematoxylin-stained tumor sections. Figure 2 shows manually selected outlines of the boundaries of MV-NIS–infected syncytia. After examining 10 representative sections the mean ± SD of BxPC-3 cells per total area was 0.70 ± 0.05.


Pinhole micro-SPECT/CT for noninvasive monitoring and quantitation of oncolytic virus dispersion and percent infection in solid tumors.

Penheiter AR, Griesmann GE, Federspiel MJ, Dingli D, Russell SJ, Carlson SK - Gene Ther. (2011)

Determination of Tumor Cell and Stroma Percentages within a Human Pancreatic Cancer Xenograft. Hematoxylin-stained, frozen sections (original magnification, ×200) were analyzed to determine the percentage of tumor occupied by BxPC-3 cells in 5 MV-NIS-infected and 3 uninfected control tumors. The rectangle represents a known area, and regions of interest (ie, stroma [fibroblasts, collagen, etc]) were outlined manually for image analysis.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3198860&req=5

Figure 2: Determination of Tumor Cell and Stroma Percentages within a Human Pancreatic Cancer Xenograft. Hematoxylin-stained, frozen sections (original magnification, ×200) were analyzed to determine the percentage of tumor occupied by BxPC-3 cells in 5 MV-NIS-infected and 3 uninfected control tumors. The rectangle represents a known area, and regions of interest (ie, stroma [fibroblasts, collagen, etc]) were outlined manually for image analysis.
Mentions: Because MV-NIS infects only human tumor cells and not mouse stromal cells, any volume-based method of infection quantitation requires an estimate of the tumor volume occupied by tumor cells (versus stroma). First, we manually determined the percentage of tumor occupied by BxPC-3 cancer cells and by stroma by using region-of-interest image analysis on hematoxylin-stained tumor sections. Figure 2 shows manually selected outlines of the boundaries of MV-NIS–infected syncytia. After examining 10 representative sections the mean ± SD of BxPC-3 cells per total area was 0.70 ± 0.05.

Bottom Line: The purpose of our study was to validate the ability of pinhole micro-single-photon emission computed tomography/computed tomography (SPECT/CT) to: 1) accurately resolve the intratumoral dispersion pattern and 2) quantify the infection percentage in solid tumors of an oncolytic measles virus encoding the human sodium iodide symporter (MV-NIS).We reliably resolved multiple distinct intratumoral zones of infection from non-infected regions.Pinhole micro-SPECT/CT imaging using the NIS reporter demonstrated precise localization and quantitation of oncolytic MV-NIS infection, and can replace more time-consuming and expensive analyses (for example, autoradiography and IHC) that require animal killing.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Medicine, Mayo Clinic, Rochester, MN 55905, USA.

ABSTRACT
The purpose of our study was to validate the ability of pinhole micro-single-photon emission computed tomography/computed tomography (SPECT/CT) to: 1) accurately resolve the intratumoral dispersion pattern and 2) quantify the infection percentage in solid tumors of an oncolytic measles virus encoding the human sodium iodide symporter (MV-NIS). Sodium iodide symporter (NIS) RNA level and dispersion pattern were determined in control and MV-NIS-infected BxPC-3 pancreatic tumor cells and mouse xenografts using quantitative, real-time, reverse transcriptase, polymerase chain reaction, autoradiography and immunohistochemistry (IHC). Mice with BxPC-3 xenografts were imaged with (123)I or (99)TcO(4) micro-SPECT/CT. Tumor dimensions and radionuclide localization were determined with imaging software. Linear regression and correlation analyses were performed to determine the relationship between tumor infection percentage and radionuclide uptake (% injected dose per gram) above background and a highly significant correlation was observed (r(2)=0.947). A detection threshold of 1.5-fold above the control tumor uptake (background) yielded a sensitivity of 2.7% MV-NIS-infected tumor cells. We reliably resolved multiple distinct intratumoral zones of infection from non-infected regions. Pinhole micro-SPECT/CT imaging using the NIS reporter demonstrated precise localization and quantitation of oncolytic MV-NIS infection, and can replace more time-consuming and expensive analyses (for example, autoradiography and IHC) that require animal killing.

Show MeSH
Related in: MedlinePlus