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In vivo detection of c-Met expression in a rat C6 glioma model.

Towner RA, Smith N, Doblas S, Tesiram Y, Garteiser P, Saunders D, Cranford R, Silasi-Mansat R, Herlea O, Ivanciu L, Wu D, Lupu F - J. Cell. Mol. Med. (2007)

Bottom Line: The tyrosine kinase receptor, c-Met, and its substrate, the hepatocyte growth factor (HGF), are implicated in the malignant progression of glioblastomas.In vivo detection of c-Met expression may be helpful in the diagnosis of malignant tumours.This is the first successful visualization of in vivo overexpression of c-Met in gliomas.

View Article: PubMed Central - PubMed

Affiliation: Small Animal MRI Core Facility, Oklahoma City, OK, USA. Rheal-Towner@omrf.org

ABSTRACT
The tyrosine kinase receptor, c-Met, and its substrate, the hepatocyte growth factor (HGF), are implicated in the malignant progression of glioblastomas. In vivo detection of c-Met expression may be helpful in the diagnosis of malignant tumours. The C6 rat glioma model is a widely used intracranial brain tumour model used to study gliomas experimentally. We used a magnetic resonance imaging (MRI) molecular targeting agent to specifically tag the cell surface receptor, c-Met, with an anti-c-Met antibody (Ab) linked to biotinylated Gd (gadolinium)-DTPA (diethylene triamine penta acetic acid)-albumin in rat gliomas to detect overexpression of this antigen in vivo. The anti-c-Met probe (anti-c-Met-Gd-DTPA-albumin) was administered intravenously, and as determined by an increase in MRI signal intensity and a corresponding decrease in regional T(1) relaxation values, this probe was found to detect increased expression of c-Met protein levels in C6 gliomas. In addition, specificity for the binding of the anti-c-Met contrast agent was determined by using fluorescence microscopic imaging of the biotinylated portion of the targeting agent within neoplastic and 'normal'brain tissues following in vivo administration of the anti-c-Met probe. Controls with no Ab or with a normal rat IgG attached to the contrast agent component indicated no non-specific binding to glioma tissue. This is the first successful visualization of in vivo overexpression of c-Met in gliomas.

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Biotinyl-BSA-Gd-DTPA-based molecular targeting agent. Anti-c-Met Ab was conjugated to the albumin via a sulfo-link (B). A similar procedure was used for a normal rat IgG probe used as a control, in addition to the (A) non-Ab control (biotinyl-BSA-Gd-DTPA without Ab). Diagram for biotinyl-BSA-Gd-DTPA modified from ref.39.
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fig02: Biotinyl-BSA-Gd-DTPA-based molecular targeting agent. Anti-c-Met Ab was conjugated to the albumin via a sulfo-link (B). A similar procedure was used for a normal rat IgG probe used as a control, in addition to the (A) non-Ab control (biotinyl-BSA-Gd-DTPA without Ab). Diagram for biotinyl-BSA-Gd-DTPA modified from ref.39.

Mentions: In order to detect c-Met overexpression in the gliomas, we used a Gd-DTPA-albumin-based molecular targeting agent (illustration in Fig. 2), of which the Gd-DTPA-albumin moiety was previously used as a vascular MR contrast agent [35, 40]. Representative results using an albumin Gd-DTPA-based anti-c-Met molecular targeting agent in a C6 rat glioma model are shown in Fig. 3. Figure 3(A–C) depicts a series of T1w MR images taken pre-target agent administration (A) and a few post-contrast images taken at (B) 25 min. and (C) 3 hrs following intravenous (tail vein) administration of the Gd-DTPA-albumin-anti-c-Met targeting agent. As can be seen, there was an uptake of the targeting agent over 3 hrs. More long-term evaluation indicated that the anti-c-Met targeting agent persisted in gliomas for at least 24 hrs, and the MR signal intensity started to return to normal after 48 hrs (data not shown). Figure 3E is a histological image obtained from the normal brain tissue, as outlined in Fig. 3B. Figure 3G is a histological slide obtained from the tumour border, as illustrated in Fig. 3C. Figure 3H is a histological image obtained within a tumour necrotic centre, as outlined in Fig. 3C. Figures 3F and 3I depict the fluorescence staining for the biotinylated Gd-DTPA-albumin-anti-c-Met targeting agent (3 hrs after administration and following in vivo MRI investigations and excision of normal and glioma tissues) with a Cy3-streptavidin that binds the biotin located on the molecular targeting agent in the glioma (I) versus the normal side of the brain (F). The Gd-albumin-anti-c-Met targeting agent was clearly bound to regions of the C6 glioma, whereas the normal contralateral tissue had low-immunofluorescence staining for the targeting agent.


In vivo detection of c-Met expression in a rat C6 glioma model.

Towner RA, Smith N, Doblas S, Tesiram Y, Garteiser P, Saunders D, Cranford R, Silasi-Mansat R, Herlea O, Ivanciu L, Wu D, Lupu F - J. Cell. Mol. Med. (2007)

Biotinyl-BSA-Gd-DTPA-based molecular targeting agent. Anti-c-Met Ab was conjugated to the albumin via a sulfo-link (B). A similar procedure was used for a normal rat IgG probe used as a control, in addition to the (A) non-Ab control (biotinyl-BSA-Gd-DTPA without Ab). Diagram for biotinyl-BSA-Gd-DTPA modified from ref.39.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3823479&req=5

fig02: Biotinyl-BSA-Gd-DTPA-based molecular targeting agent. Anti-c-Met Ab was conjugated to the albumin via a sulfo-link (B). A similar procedure was used for a normal rat IgG probe used as a control, in addition to the (A) non-Ab control (biotinyl-BSA-Gd-DTPA without Ab). Diagram for biotinyl-BSA-Gd-DTPA modified from ref.39.
Mentions: In order to detect c-Met overexpression in the gliomas, we used a Gd-DTPA-albumin-based molecular targeting agent (illustration in Fig. 2), of which the Gd-DTPA-albumin moiety was previously used as a vascular MR contrast agent [35, 40]. Representative results using an albumin Gd-DTPA-based anti-c-Met molecular targeting agent in a C6 rat glioma model are shown in Fig. 3. Figure 3(A–C) depicts a series of T1w MR images taken pre-target agent administration (A) and a few post-contrast images taken at (B) 25 min. and (C) 3 hrs following intravenous (tail vein) administration of the Gd-DTPA-albumin-anti-c-Met targeting agent. As can be seen, there was an uptake of the targeting agent over 3 hrs. More long-term evaluation indicated that the anti-c-Met targeting agent persisted in gliomas for at least 24 hrs, and the MR signal intensity started to return to normal after 48 hrs (data not shown). Figure 3E is a histological image obtained from the normal brain tissue, as outlined in Fig. 3B. Figure 3G is a histological slide obtained from the tumour border, as illustrated in Fig. 3C. Figure 3H is a histological image obtained within a tumour necrotic centre, as outlined in Fig. 3C. Figures 3F and 3I depict the fluorescence staining for the biotinylated Gd-DTPA-albumin-anti-c-Met targeting agent (3 hrs after administration and following in vivo MRI investigations and excision of normal and glioma tissues) with a Cy3-streptavidin that binds the biotin located on the molecular targeting agent in the glioma (I) versus the normal side of the brain (F). The Gd-albumin-anti-c-Met targeting agent was clearly bound to regions of the C6 glioma, whereas the normal contralateral tissue had low-immunofluorescence staining for the targeting agent.

Bottom Line: The tyrosine kinase receptor, c-Met, and its substrate, the hepatocyte growth factor (HGF), are implicated in the malignant progression of glioblastomas.In vivo detection of c-Met expression may be helpful in the diagnosis of malignant tumours.This is the first successful visualization of in vivo overexpression of c-Met in gliomas.

View Article: PubMed Central - PubMed

Affiliation: Small Animal MRI Core Facility, Oklahoma City, OK, USA. Rheal-Towner@omrf.org

ABSTRACT
The tyrosine kinase receptor, c-Met, and its substrate, the hepatocyte growth factor (HGF), are implicated in the malignant progression of glioblastomas. In vivo detection of c-Met expression may be helpful in the diagnosis of malignant tumours. The C6 rat glioma model is a widely used intracranial brain tumour model used to study gliomas experimentally. We used a magnetic resonance imaging (MRI) molecular targeting agent to specifically tag the cell surface receptor, c-Met, with an anti-c-Met antibody (Ab) linked to biotinylated Gd (gadolinium)-DTPA (diethylene triamine penta acetic acid)-albumin in rat gliomas to detect overexpression of this antigen in vivo. The anti-c-Met probe (anti-c-Met-Gd-DTPA-albumin) was administered intravenously, and as determined by an increase in MRI signal intensity and a corresponding decrease in regional T(1) relaxation values, this probe was found to detect increased expression of c-Met protein levels in C6 gliomas. In addition, specificity for the binding of the anti-c-Met contrast agent was determined by using fluorescence microscopic imaging of the biotinylated portion of the targeting agent within neoplastic and 'normal'brain tissues following in vivo administration of the anti-c-Met probe. Controls with no Ab or with a normal rat IgG attached to the contrast agent component indicated no non-specific binding to glioma tissue. This is the first successful visualization of in vivo overexpression of c-Met in gliomas.

Show MeSH
Related in: MedlinePlus