Search

Radionuclide molecular imaging could provide an accurate assessment of the expression of molecular targets in disseminated cancers enabling stratification of patients for specific therapies. B7-H3 (CD276) is a transmembrane protein belonging to the B7 superfamily. This protein is overexpressed in different types of human malignancies and such upregulation is generally associated with a poor clinical prognosis. In this study, targeting properties of an Affibody-based probe, AC12, containing a -GGGC amino acid sequence as a chelator (designated as AC12-GGGC) labelled with technetium-99m (Tc-99m) were evaluated for imaging of B7-H3-expressing tumours. AC12-GGGC was efficiently labelled with Tc-99m. [Tc-99m]Tc-AC12-GGGC bound specifically to B7-H3 expressing cells in vitro with affinities in nanomolar range. In mice bearing B7-H3-expressing xenografts, [Tc-99m]Tc-AC12-GGGC showed tumour uptake of 2.1 +/- 0.5 %ID/g at 2 h after injection. Its clearance from blood, normal organs and tissues was very rapid. This new targeting agent, [Tc-99m]Tc-AC12-GGGC, provided high tumour-to-blood ratio already at 2 h (8.2 +/- 1.9), which increased to 11.0 +/- 0.5 at 4 h after injection. Significantly (p < 0.05) higher tumour-to-liver and higher tumour-to-bone ratios at 2 h in comparison with 4 h after injection were observed. Thus, [Tc-99m]Tc-AC12-GGGC could be a promising candidate for further development.

The Insulin-like growth factor-1 receptor (IGF-1R) is a molecular target for several monoclonal antibodies undergoing clinical evaluation as anticancer therapeutics. The non-invasive detection of IGF-1R expression in tumors might enable stratification of patients for specific treatment and improve the outcome of both clinical trials and routine treatment. The affibody molecule Z(IGF-1R:4551) binds specifically to IGF-1R with subnanomolar affinity. The goal of this study was to evaluate the Ga-68 and In-111-labeled affibody construct NODAGA-(HE)(3)-Z(IGF-1R:4551) for the imaging of IGF-1R expression, using PET and SPECT. The labeling was efficient and provided stable coupling of both radionuclides. The two imaging probes, [Ga-68]Ga-NODAGA-(HE)(3)-Z(IGF-1R:4551) and [In-111]In-NODAGA-(HE)(3)-Z(IGF-1R:4551), demonstrated specific binding to IGF-1R-expressing human cancer cell lines in vitro and to IGF-1R-expressing xenografts in mice. Preclinical PET and SPECT/CT imaging demonstrated visualization of IGF-1R-expressing xenografts already one hour after injection. The tumor-to-blood ratios at 3 h after injection were 7.8 +/- 0.2 and 8.0 +/- 0.6 for [Ga-68]Ga-NODAGA-(HE)(3)-Z(IGF-1R:4551) and [In-111]In-NODAGA-(HE)(3)-Z(IGF-1R:4551), respectively. In conclusion, a molecular design of the Z(IGF-1R:4551) affibody molecule, including placement of a (HE)(3)-tag on the N-terminus and site-specific coupling of a NODAGA chelator on the C-terminus, provides a tracer with improved imaging properties for visualization of IGF-1R in malignant tumors, using PET and SPECT.

Radionuclide molecular imaging could provide an accurate assessment of the expression of molecular targets in disseminated cancers enabling stratification of patients for specific therapies. B7-H3 (CD276) is a transmembrane protein belonging to the B7 superfamily. This protein is overexpressed in different types of human malignancies and such upregulation is generally associated with a poor clinical prognosis. In this study, targeting properties of an Affibody-based probe, AC12, containing a -GGGC amino acid sequence as a chelator (designated as AC12-GGGC) labelled with technetium-99m (Tc-99m) were evaluated for imaging of B7-H3-expressing tumours. AC12-GGGC was efficiently labelled with Tc-99m. [Tc-99m]Tc-AC12-GGGC bound specifically to B7-H3 expressing cells in vitro with affinities in nanomolar range. In mice bearing B7-H3-expressing xenografts, [Tc-99m]Tc-AC12-GGGC showed tumour uptake of 2.1 +/- 0.5 %ID/g at 2 h after injection. Its clearance from blood, normal organs and tissues was very rapid. This new targeting agent, [Tc-99m]Tc-AC12-GGGC, provided high tumour-to-blood ratio already at 2 h (8.2 +/- 1.9), which increased to 11.0 +/- 0.5 at 4 h after injection. Significantly (p < 0.05) higher tumour-to-liver and higher tumour-to-bone ratios at 2 h in comparison with 4 h after injection were observed. Thus, [Tc-99m]Tc-AC12-GGGC could be a promising candidate for further development.

The Insulin-like growth factor-1 receptor (IGF-1R) is a molecular target for several monoclonal antibodies undergoing clinical evaluation as anticancer therapeutics. The non-invasive detection of IGF-1R expression in tumors might enable stratification of patients for specific treatment and improve the outcome of both clinical trials and routine treatment. The affibody molecule Z(IGF-1R:4551) binds specifically to IGF-1R with subnanomolar affinity. The goal of this study was to evaluate the Ga-68 and In-111-labeled affibody construct NODAGA-(HE)(3)-Z(IGF-1R:4551) for the imaging of IGF-1R expression, using PET and SPECT. The labeling was efficient and provided stable coupling of both radionuclides. The two imaging probes, [Ga-68]Ga-NODAGA-(HE)(3)-Z(IGF-1R:4551) and [In-111]In-NODAGA-(HE)(3)-Z(IGF-1R:4551), demonstrated specific binding to IGF-1R-expressing human cancer cell lines in vitro and to IGF-1R-expressing xenografts in mice. Preclinical PET and SPECT/CT imaging demonstrated visualization of IGF-1R-expressing xenografts already one hour after injection. The tumor-to-blood ratios at 3 h after injection were 7.8 +/- 0.2 and 8.0 +/- 0.6 for [Ga-68]Ga-NODAGA-(HE)(3)-Z(IGF-1R:4551) and [In-111]In-NODAGA-(HE)(3)-Z(IGF-1R:4551), respectively. In conclusion, a molecular design of the Z(IGF-1R:4551) affibody molecule, including placement of a (HE)(3)-tag on the N-terminus and site-specific coupling of a NODAGA chelator on the C-terminus, provides a tracer with improved imaging properties for visualization of IGF-1R in malignant tumors, using PET and SPECT.

Radionuclide molecular imaging could provide an accurate assessment of the expression of molecular targets in disseminated cancers enabling stratification of patients for specific therapies. B7-H3 (CD276) is a transmembrane protein belonging to the B7 superfamily. This protein is overexpressed in different types of human malignancies and such upregulation is generally associated with a poor clinical prognosis. In this study, targeting properties of an Affibody-based probe, AC12, containing a -GGGC amino acid sequence as a chelator (designated as AC12-GGGC) labelled with technetium-99m (Tc-99m) were evaluated for imaging of B7-H3-expressing tumours. AC12-GGGC was efficiently labelled with Tc-99m. [Tc-99m]Tc-AC12-GGGC bound specifically to B7-H3 expressing cells in vitro with affinities in nanomolar range. In mice bearing B7-H3-expressing xenografts, [Tc-99m]Tc-AC12-GGGC showed tumour uptake of 2.1 +/- 0.5 %ID/g at 2 h after injection. Its clearance from blood, normal organs and tissues was very rapid. This new targeting agent, [Tc-99m]Tc-AC12-GGGC, provided high tumour-to-blood ratio already at 2 h (8.2 +/- 1.9), which increased to 11.0 +/- 0.5 at 4 h after injection. Significantly (p < 0.05) higher tumour-to-liver and higher tumour-to-bone ratios at 2 h in comparison with 4 h after injection were observed. Thus, [Tc-99m]Tc-AC12-GGGC could be a promising candidate for further development.

The Insulin-like growth factor-1 receptor (IGF-1R) is a molecular target for several monoclonal antibodies undergoing clinical evaluation as anticancer therapeutics. The non-invasive detection of IGF-1R expression in tumors might enable stratification of patients for specific treatment and improve the outcome of both clinical trials and routine treatment. The affibody molecule Z(IGF-1R:4551) binds specifically to IGF-1R with subnanomolar affinity. The goal of this study was to evaluate the Ga-68 and In-111-labeled affibody construct NODAGA-(HE)(3)-Z(IGF-1R:4551) for the imaging of IGF-1R expression, using PET and SPECT. The labeling was efficient and provided stable coupling of both radionuclides. The two imaging probes, [Ga-68]Ga-NODAGA-(HE)(3)-Z(IGF-1R:4551) and [In-111]In-NODAGA-(HE)(3)-Z(IGF-1R:4551), demonstrated specific binding to IGF-1R-expressing human cancer cell lines in vitro and to IGF-1R-expressing xenografts in mice. Preclinical PET and SPECT/CT imaging demonstrated visualization of IGF-1R-expressing xenografts already one hour after injection. The tumor-to-blood ratios at 3 h after injection were 7.8 +/- 0.2 and 8.0 +/- 0.6 for [Ga-68]Ga-NODAGA-(HE)(3)-Z(IGF-1R:4551) and [In-111]In-NODAGA-(HE)(3)-Z(IGF-1R:4551), respectively. In conclusion, a molecular design of the Z(IGF-1R:4551) affibody molecule, including placement of a (HE)(3)-tag on the N-terminus and site-specific coupling of a NODAGA chelator on the C-terminus, provides a tracer with improved imaging properties for visualization of IGF-1R in malignant tumors, using PET and SPECT.

Targeted drug conjugates based on Affibody molecules fused to an albumin-binding domain (ABD) for half-life extension have demonstrated potent anti-tumor activity in preclinical therapeutic studies. Furthermore, optimization of their molecular design might increase the cytotoxic effect on tumors and minimize systemic toxicity. This study aimed to investigate the influence of length and composition of a linker between the human epidermal growth factor receptor 2 (HER2)-targeted affibody molecule (Z(HER2:2891)) and the ABD domain on functionality and biodistribution of affibody-drug conjugates containing a microtubulin inhibitor mertansin (mcDM1) (AffiDCs). Two conjugates, having a trimeric (S(3)G)(3) linker or a trimeric (G(3)S)(3) linker were produced, radiolabeled with Tc-99m(CO)(3), and compared side-by-side in vitro and in vivo with the original Z(HER2:2891)-G(4)S-ABD-mcDM1 conjugate having a monomeric G(4)S linker. Both conjugates with longer linkers had a decreased affinity to HER2 and mouse and human serum albumin in vitro, however, no differences in blood retention were observed in NMRI mice up to 24 h post injection. The use of both (S(3)G)(3) and (G(3)S)(3) linkers reduced liver uptake of AffiDCs by approximately 1.2-fold compared with the use of a G(4)S linker. This finding provides important insights into the molecular design for the development of targeted drug conjugates with reduced hepatic uptake., De två första författarna delar förstaförfattarskapet.

Targeted drug conjugates based on Affibody molecules fused to an albumin-binding domain (ABD) for half-life extension have demonstrated potent anti-tumor activity in preclinical therapeutic studies. Furthermore, optimization of their molecular design might increase the cytotoxic effect on tumors and minimize systemic toxicity. This study aimed to investigate the influence of length and composition of a linker between the human epidermal growth factor receptor 2 (HER2)-targeted affibody molecule (Z(HER2:2891)) and the ABD domain on functionality and biodistribution of affibody-drug conjugates containing a microtubulin inhibitor mertansin (mcDM1) (AffiDCs). Two conjugates, having a trimeric (S(3)G)(3) linker or a trimeric (G(3)S)(3) linker were produced, radiolabeled with Tc-99m(CO)(3), and compared side-by-side in vitro and in vivo with the original Z(HER2:2891)-G(4)S-ABD-mcDM1 conjugate having a monomeric G(4)S linker. Both conjugates with longer linkers had a decreased affinity to HER2 and mouse and human serum albumin in vitro, however, no differences in blood retention were observed in NMRI mice up to 24 h post injection. The use of both (S(3)G)(3) and (G(3)S)(3) linkers reduced liver uptake of AffiDCs by approximately 1.2-fold compared with the use of a G(4)S linker. This finding provides important insights into the molecular design for the development of targeted drug conjugates with reduced hepatic uptake., De två första författarna delar förstaförfattarskapet.

Targeted drug conjugates based on Affibody molecules fused to an albumin-binding domain (ABD) for half-life extension have demonstrated potent anti-tumor activity in preclinical therapeutic studies. Furthermore, optimization of their molecular design might increase the cytotoxic effect on tumors and minimize systemic toxicity. This study aimed to investigate the influence of length and composition of a linker between the human epidermal growth factor receptor 2 (HER2)-targeted affibody molecule (Z(HER2:2891)) and the ABD domain on functionality and biodistribution of affibody-drug conjugates containing a microtubulin inhibitor mertansin (mcDM1) (AffiDCs). Two conjugates, having a trimeric (S(3)G)(3) linker or a trimeric (G(3)S)(3) linker were produced, radiolabeled with Tc-99m(CO)(3), and compared side-by-side in vitro and in vivo with the original Z(HER2:2891)-G(4)S-ABD-mcDM1 conjugate having a monomeric G(4)S linker. Both conjugates with longer linkers had a decreased affinity to HER2 and mouse and human serum albumin in vitro, however, no differences in blood retention were observed in NMRI mice up to 24 h post injection. The use of both (S(3)G)(3) and (G(3)S)(3) linkers reduced liver uptake of AffiDCs by approximately 1.2-fold compared with the use of a G(4)S linker. This finding provides important insights into the molecular design for the development of targeted drug conjugates with reduced hepatic uptake., QC 20220426

Targeted drug conjugates based on Affibody molecules fused to an albumin-binding domain (ABD) for half-life extension have demonstrated potent anti-tumor activity in preclinical therapeutic studies. Furthermore, optimization of their molecular design might increase the cytotoxic effect on tumors and minimize systemic toxicity. This study aimed to investigate the influence of length and composition of a linker between the human epidermal growth factor receptor 2 (HER2)-targeted affibody molecule (Z(HER2:2891)) and the ABD domain on functionality and biodistribution of affibody-drug conjugates containing a microtubulin inhibitor mertansin (mcDM1) (AffiDCs). Two conjugates, having a trimeric (S(3)G)(3) linker or a trimeric (G(3)S)(3) linker were produced, radiolabeled with Tc-99m(CO)(3), and compared side-by-side in vitro and in vivo with the original Z(HER2:2891)-G(4)S-ABD-mcDM1 conjugate having a monomeric G(4)S linker. Both conjugates with longer linkers had a decreased affinity to HER2 and mouse and human serum albumin in vitro, however, no differences in blood retention were observed in NMRI mice up to 24 h post injection. The use of both (S(3)G)(3) and (G(3)S)(3) linkers reduced liver uptake of AffiDCs by approximately 1.2-fold compared with the use of a G(4)S linker. This finding provides important insights into the molecular design for the development of targeted drug conjugates with reduced hepatic uptake., De två första författarna delar förstaförfattarskapet.

Radionuclide molecular imaging could provide an accurate assessment of the expression of molecular targets in disseminated cancers enabling stratification of patients for specific therapies. B7-H3 (CD276) is a transmembrane protein belonging to the B7 superfamily. This protein is overexpressed in different types of human malignancies and such upregulation is generally associated with a poor clinical prognosis. In this study, targeting properties of an Affibody-based probe, AC12, containing a -GGGC amino acid sequence as a chelator (designated as AC12-GGGC) labelled with technetium-99m (Tc-99m) were evaluated for imaging of B7-H3-expressing tumours. AC12-GGGC was efficiently labelled with Tc-99m. [Tc-99m]Tc-AC12-GGGC bound specifically to B7-H3 expressing cells in vitro with affinities in nanomolar range. In mice bearing B7-H3-expressing xenografts, [Tc-99m]Tc-AC12-GGGC showed tumour uptake of 2.1 +/- 0.5 %ID/g at 2 h after injection. Its clearance from blood, normal organs and tissues was very rapid. This new targeting agent, [Tc-99m]Tc-AC12-GGGC, provided high tumour-to-blood ratio already at 2 h (8.2 +/- 1.9), which increased to 11.0 +/- 0.5 at 4 h after injection. Significantly (p < 0.05) higher tumour-to-liver and higher tumour-to-bone ratios at 2 h in comparison with 4 h after injection were observed. Thus, [Tc-99m]Tc-AC12-GGGC could be a promising candidate for further development.

The Insulin-like growth factor-1 receptor (IGF-1R) is a molecular target for several monoclonal antibodies undergoing clinical evaluation as anticancer therapeutics. The non-invasive detection of IGF-1R expression in tumors might enable stratification of patients for specific treatment and improve the outcome of both clinical trials and routine treatment. The affibody molecule Z(IGF-1R:4551) binds specifically to IGF-1R with subnanomolar affinity. The goal of this study was to evaluate the Ga-68 and In-111-labeled affibody construct NODAGA-(HE)(3)-Z(IGF-1R:4551) for the imaging of IGF-1R expression, using PET and SPECT. The labeling was efficient and provided stable coupling of both radionuclides. The two imaging probes, [Ga-68]Ga-NODAGA-(HE)(3)-Z(IGF-1R:4551) and [In-111]In-NODAGA-(HE)(3)-Z(IGF-1R:4551), demonstrated specific binding to IGF-1R-expressing human cancer cell lines in vitro and to IGF-1R-expressing xenografts in mice. Preclinical PET and SPECT/CT imaging demonstrated visualization of IGF-1R-expressing xenografts already one hour after injection. The tumor-to-blood ratios at 3 h after injection were 7.8 +/- 0.2 and 8.0 +/- 0.6 for [Ga-68]Ga-NODAGA-(HE)(3)-Z(IGF-1R:4551) and [In-111]In-NODAGA-(HE)(3)-Z(IGF-1R:4551), respectively. In conclusion, a molecular design of the Z(IGF-1R:4551) affibody molecule, including placement of a (HE)(3)-tag on the N-terminus and site-specific coupling of a NODAGA chelator on the C-terminus, provides a tracer with improved imaging properties for visualization of IGF-1R in malignant tumors, using PET and SPECT.

The Insulin-like growth factor-1 receptor (IGF-1R) is a molecular target for several monoclonal antibodies undergoing clinical evaluation as anticancer therapeutics. The non-invasive detection of IGF-1R expression in tumors might enable stratification of patients for specific treatment and improve the outcome of both clinical trials and routine treatment. The affibody molecule Z(IGF-1R:4551) binds specifically to IGF-1R with subnanomolar affinity. The goal of this study was to evaluate the Ga-68 and In-111-labeled affibody construct NODAGA-(HE)(3)-Z(IGF-1R:4551) for the imaging of IGF-1R expression, using PET and SPECT. The labeling was efficient and provided stable coupling of both radionuclides. The two imaging probes, [Ga-68]Ga-NODAGA-(HE)(3)-Z(IGF-1R:4551) and [In-111]In-NODAGA-(HE)(3)-Z(IGF-1R:4551), demonstrated specific binding to IGF-1R-expressing human cancer cell lines in vitro and to IGF-1R-expressing xenografts in mice. Preclinical PET and SPECT/CT imaging demonstrated visualization of IGF-1R-expressing xenografts already one hour after injection. The tumor-to-blood ratios at 3 h after injection were 7.8 +/- 0.2 and 8.0 +/- 0.6 for [Ga-68]Ga-NODAGA-(HE)(3)-Z(IGF-1R:4551) and [In-111]In-NODAGA-(HE)(3)-Z(IGF-1R:4551), respectively. In conclusion, a molecular design of the Z(IGF-1R:4551) affibody molecule, including placement of a (HE)(3)-tag on the N-terminus and site-specific coupling of a NODAGA chelator on the C-terminus, provides a tracer with improved imaging properties for visualization of IGF-1R in malignant tumors, using PET and SPECT., QC 20220809

Targeted drug conjugates based on Affibody molecules fused to an albumin-binding domain (ABD) for half-life extension have demonstrated potent anti-tumor activity in preclinical therapeutic studies. Furthermore, optimization of their molecular design might increase the cytotoxic effect on tumors and minimize systemic toxicity. This study aimed to investigate the influence of length and composition of a linker between the human epidermal growth factor receptor 2 (HER2)-targeted affibody molecule (Z(HER2:2891)) and the ABD domain on functionality and biodistribution of affibody-drug conjugates containing a microtubulin inhibitor mertansin (mcDM1) (AffiDCs). Two conjugates, having a trimeric (S(3)G)(3) linker or a trimeric (G(3)S)(3) linker were produced, radiolabeled with Tc-99m(CO)(3), and compared side-by-side in vitro and in vivo with the original Z(HER2:2891)-G(4)S-ABD-mcDM1 conjugate having a monomeric G(4)S linker. Both conjugates with longer linkers had a decreased affinity to HER2 and mouse and human serum albumin in vitro, however, no differences in blood retention were observed in NMRI mice up to 24 h post injection. The use of both (S(3)G)(3) and (G(3)S)(3) linkers reduced liver uptake of AffiDCs by approximately 1.2-fold compared with the use of a G(4)S linker. This finding provides important insights into the molecular design for the development of targeted drug conjugates with reduced hepatic uptake., De två första författarna delar förstaförfattarskapet.

The Insulin-like growth factor-1 receptor (IGF-1R) is a molecular target for several monoclonal antibodies undergoing clinical evaluation as anticancer therapeutics. The non-invasive detection of IGF-1R expression in tumors might enable stratification of patients for specific treatment and improve the outcome of both clinical trials and routine treatment. The affibody molecule Z(IGF-1R:4551) binds specifically to IGF-1R with subnanomolar affinity. The goal of this study was to evaluate the Ga-68 and In-111-labeled affibody construct NODAGA-(HE)(3)-Z(IGF-1R:4551) for the imaging of IGF-1R expression, using PET and SPECT. The labeling was efficient and provided stable coupling of both radionuclides. The two imaging probes, [Ga-68]Ga-NODAGA-(HE)(3)-Z(IGF-1R:4551) and [In-111]In-NODAGA-(HE)(3)-Z(IGF-1R:4551), demonstrated specific binding to IGF-1R-expressing human cancer cell lines in vitro and to IGF-1R-expressing xenografts in mice. Preclinical PET and SPECT/CT imaging demonstrated visualization of IGF-1R-expressing xenografts already one hour after injection. The tumor-to-blood ratios at 3 h after injection were 7.8 +/- 0.2 and 8.0 +/- 0.6 for [Ga-68]Ga-NODAGA-(HE)(3)-Z(IGF-1R:4551) and [In-111]In-NODAGA-(HE)(3)-Z(IGF-1R:4551), respectively. In conclusion, a molecular design of the Z(IGF-1R:4551) affibody molecule, including placement of a (HE)(3)-tag on the N-terminus and site-specific coupling of a NODAGA chelator on the C-terminus, provides a tracer with improved imaging properties for visualization of IGF-1R in malignant tumors, using PET and SPECT.

Radionuclide molecular imaging could provide an accurate assessment of the expression of molecular targets in disseminated cancers enabling stratification of patients for specific therapies. B7-H3 (CD276) is a transmembrane protein belonging to the B7 superfamily. This protein is overexpressed in different types of human malignancies and such upregulation is generally associated with a poor clinical prognosis. In this study, targeting properties of an Affibody-based probe, AC12, containing a -GGGC amino acid sequence as a chelator (designated as AC12-GGGC) labelled with technetium-99m (Tc-99m) were evaluated for imaging of B7-H3-expressing tumours. AC12-GGGC was efficiently labelled with Tc-99m. [Tc-99m]Tc-AC12-GGGC bound specifically to B7-H3 expressing cells in vitro with affinities in nanomolar range. In mice bearing B7-H3-expressing xenografts, [Tc-99m]Tc-AC12-GGGC showed tumour uptake of 2.1 +/- 0.5 %ID/g at 2 h after injection. Its clearance from blood, normal organs and tissues was very rapid. This new targeting agent, [Tc-99m]Tc-AC12-GGGC, provided high tumour-to-blood ratio already at 2 h (8.2 +/- 1.9), which increased to 11.0 +/- 0.5 at 4 h after injection. Significantly (p < 0.05) higher tumour-to-liver and higher tumour-to-bone ratios at 2 h in comparison with 4 h after injection were observed. Thus, [Tc-99m]Tc-AC12-GGGC could be a promising candidate for further development.

Targeted drug conjugates based on Affibody molecules fused to an albumin-binding domain (ABD) for half-life extension have demonstrated potent anti-tumor activity in preclinical therapeutic studies. Furthermore, optimization of their molecular design might increase the cytotoxic effect on tumors and minimize systemic toxicity. This study aimed to investigate the influence of length and composition of a linker between the human epidermal growth factor receptor 2 (HER2)-targeted affibody molecule (Z(HER2:2891)) and the ABD domain on functionality and biodistribution of affibody-drug conjugates containing a microtubulin inhibitor mertansin (mcDM1) (AffiDCs). Two conjugates, having a trimeric (S(3)G)(3) linker or a trimeric (G(3)S)(3) linker were produced, radiolabeled with Tc-99m(CO)(3), and compared side-by-side in vitro and in vivo with the original Z(HER2:2891)-G(4)S-ABD-mcDM1 conjugate having a monomeric G(4)S linker. Both conjugates with longer linkers had a decreased affinity to HER2 and mouse and human serum albumin in vitro, however, no differences in blood retention were observed in NMRI mice up to 24 h post injection. The use of both (S(3)G)(3) and (G(3)S)(3) linkers reduced liver uptake of AffiDCs by approximately 1.2-fold compared with the use of a G(4)S linker. This finding provides important insights into the molecular design for the development of targeted drug conjugates with reduced hepatic uptake., De två första författarna delar förstaförfattarskapet.

Simple Summary Affibody molecules are small, engineered affinity proteins based on a nonimmunoglobulin scaffold. Affibody-based radionuclide imaging probes have demonstrated excellent tumor targeting. However, the renal clearance of affibody molecules is accompanied by high reabsorption and retention of activity in the kidney, which prevents their use for radionuclide therapy. We have previously shown the feasibility of overcoming the high renal uptake using a pretargeting approach for affibody-mediated therapy based on peptide nucleic acid (PNA) hybridization. In this study, we test the hypothesis that shortening the PNA pretargeting probes would further increase the difference between the accumulation of radiometals in tumor xenografts and in kidneys. A series of novel PNA probes has been designed and evaluated in vitro and in vivo. We have found that a variant containing 9 nucleobases enables a two-fold increase of the tumor-to-kidney dose ratio compared with a variant containing 15 nucleobases. This creates preconditions for more efficient therapy of cancer. Affibody-mediated PNA-based pretargeting is a promising approach to radionuclide therapy of HER2-expressing tumors. In this study, we test the hypothesis that shortening the PNA pretargeting probes would increase the tumor-to-kidney dose ratio. The primary probe Z(HER2:342)-SR-HP15 and the complementary secondary probes HP16, HP17, and HP18, containing 9, 12, and 15 nucleobases, respectively, and carrying a 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) chelator were designed, synthesized, characterized in vitro, and labeled with Lu-177. In vitro pretargeting was studied in HER2-expressing SKOV3 and BT474 cell lines. The biodistribution of these novel probes was evaluated in immunodeficient mice bearing SKOV3 xenografts and compared to the previously studied [Lu-177]Lu-HP2. Characterization confirmed the formation of high-affinity duplexes between HP15 and the secondary probes, with the affi

Simple Summary Affibody molecules are small, engineered affinity proteins based on a nonimmunoglobulin scaffold. Affibody-based radionuclide imaging probes have demonstrated excellent tumor targeting. However, the renal clearance of affibody molecules is accompanied by high reabsorption and retention of activity in the kidney, which prevents their use for radionuclide therapy. We have previously shown the feasibility of overcoming the high renal uptake using a pretargeting approach for affibody-mediated therapy based on peptide nucleic acid (PNA) hybridization. In this study, we test the hypothesis that shortening the PNA pretargeting probes would further increase the difference between the accumulation of radiometals in tumor xenografts and in kidneys. A series of novel PNA probes has been designed and evaluated in vitro and in vivo. We have found that a variant containing 9 nucleobases enables a two-fold increase of the tumor-to-kidney dose ratio compared with a variant containing 15 nucleobases. This creates preconditions for more efficient therapy of cancer. Affibody-mediated PNA-based pretargeting is a promising approach to radionuclide therapy of HER2-expressing tumors. In this study, we test the hypothesis that shortening the PNA pretargeting probes would increase the tumor-to-kidney dose ratio. The primary probe Z(HER2:342)-SR-HP15 and the complementary secondary probes HP16, HP17, and HP18, containing 9, 12, and 15 nucleobases, respectively, and carrying a 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) chelator were designed, synthesized, characterized in vitro, and labeled with Lu-177. In vitro pretargeting was studied in HER2-expressing SKOV3 and BT474 cell lines. The biodistribution of these novel probes was evaluated in immunodeficient mice bearing SKOV3 xenografts and compared to the previously studied [Lu-177]Lu-HP2. Characterization confirmed the formation of high-affinity duplexes between HP15 and the secondary probes, with the affi

Simple Summary Affibody molecules are small, engineered affinity proteins based on a nonimmunoglobulin scaffold. Affibody-based radionuclide imaging probes have demonstrated excellent tumor targeting. However, the renal clearance of affibody molecules is accompanied by high reabsorption and retention of activity in the kidney, which prevents their use for radionuclide therapy. We have previously shown the feasibility of overcoming the high renal uptake using a pretargeting approach for affibody-mediated therapy based on peptide nucleic acid (PNA) hybridization. In this study, we test the hypothesis that shortening the PNA pretargeting probes would further increase the difference between the accumulation of radiometals in tumor xenografts and in kidneys. A series of novel PNA probes has been designed and evaluated in vitro and in vivo. We have found that a variant containing 9 nucleobases enables a two-fold increase of the tumor-to-kidney dose ratio compared with a variant containing 15 nucleobases. This creates preconditions for more efficient therapy of cancer. Affibody-mediated PNA-based pretargeting is a promising approach to radionuclide therapy of HER2-expressing tumors. In this study, we test the hypothesis that shortening the PNA pretargeting probes would increase the tumor-to-kidney dose ratio. The primary probe Z(HER2:342)-SR-HP15 and the complementary secondary probes HP16, HP17, and HP18, containing 9, 12, and 15 nucleobases, respectively, and carrying a 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) chelator were designed, synthesized, characterized in vitro, and labeled with Lu-177. In vitro pretargeting was studied in HER2-expressing SKOV3 and BT474 cell lines. The biodistribution of these novel probes was evaluated in immunodeficient mice bearing SKOV3 xenografts and compared to the previously studied [Lu-177]Lu-HP2. Characterization confirmed the formation of high-affinity duplexes between HP15 and the secondary probes, with the affi

Simple Summary Affibody molecules are small, engineered affinity proteins based on a nonimmunoglobulin scaffold. Affibody-based radionuclide imaging probes have demonstrated excellent tumor targeting. However, the renal clearance of affibody molecules is accompanied by high reabsorption and retention of activity in the kidney, which prevents their use for radionuclide therapy. We have previously shown the feasibility of overcoming the high renal uptake using a pretargeting approach for affibody-mediated therapy based on peptide nucleic acid (PNA) hybridization. In this study, we test the hypothesis that shortening the PNA pretargeting probes would further increase the difference between the accumulation of radiometals in tumor xenografts and in kidneys. A series of novel PNA probes has been designed and evaluated in vitro and in vivo. We have found that a variant containing 9 nucleobases enables a two-fold increase of the tumor-to-kidney dose ratio compared with a variant containing 15 nucleobases. This creates preconditions for more efficient therapy of cancer. Affibody-mediated PNA-based pretargeting is a promising approach to radionuclide therapy of HER2-expressing tumors. In this study, we test the hypothesis that shortening the PNA pretargeting probes would increase the tumor-to-kidney dose ratio. The primary probe Z(HER2:342)-SR-HP15 and the complementary secondary probes HP16, HP17, and HP18, containing 9, 12, and 15 nucleobases, respectively, and carrying a 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) chelator were designed, synthesized, characterized in vitro, and labeled with Lu-177. In vitro pretargeting was studied in HER2-expressing SKOV3 and BT474 cell lines. The biodistribution of these novel probes was evaluated in immunodeficient mice bearing SKOV3 xenografts and compared to the previously studied [Lu-177]Lu-HP2. Characterization confirmed the formation of high-affinity duplexes between HP15 and the secondary probes, with the affi

Simple Summary Affibody molecules are small, engineered affinity proteins based on a nonimmunoglobulin scaffold. Affibody-based radionuclide imaging probes have demonstrated excellent tumor targeting. However, the renal clearance of affibody molecules is accompanied by high reabsorption and retention of activity in the kidney, which prevents their use for radionuclide therapy. We have previously shown the feasibility of overcoming the high renal uptake using a pretargeting approach for affibody-mediated therapy based on peptide nucleic acid (PNA) hybridization. In this study, we test the hypothesis that shortening the PNA pretargeting probes would further increase the difference between the accumulation of radiometals in tumor xenografts and in kidneys. A series of novel PNA probes has been designed and evaluated in vitro and in vivo. We have found that a variant containing 9 nucleobases enables a two-fold increase of the tumor-to-kidney dose ratio compared with a variant containing 15 nucleobases. This creates preconditions for more efficient therapy of cancer. Affibody-mediated PNA-based pretargeting is a promising approach to radionuclide therapy of HER2-expressing tumors. In this study, we test the hypothesis that shortening the PNA pretargeting probes would increase the tumor-to-kidney dose ratio. The primary probe Z(HER2:342)-SR-HP15 and the complementary secondary probes HP16, HP17, and HP18, containing 9, 12, and 15 nucleobases, respectively, and carrying a 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) chelator were designed, synthesized, characterized in vitro, and labeled with Lu-177. In vitro pretargeting was studied in HER2-expressing SKOV3 and BT474 cell lines. The biodistribution of these novel probes was evaluated in immunodeficient mice bearing SKOV3 xenografts and compared to the previously studied [Lu-177]Lu-HP2. Characterization confirmed the formation of high-affinity duplexes between HP15 and the secondary probes, with the affi