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A useful EGFR-TK ligand for tumor diagnosis with SPECT: development of radioiodinated 6-(3-morpholinopropoxy)-7-ethoxy-4-(3'-iodophenoxy)quinazoline.

Hirata M, Kanai Y, Naka S, Yoshimoto M, Kagawa S, Matsumuro K, Katsuma H, Yamaguchi H, Magata Y, Ohmomo Y - Ann Nucl Med (2013)

Bottom Line: Six quinazoline derivatives were designed and synthesized, and among these, 6a-d were found to have relatively high EGFR-TK inhibitory potency.In contrast, [(125)I]PYK was rapidly cleared from peripheral tissues, resulting in a high tumor-to-tissue ratio 24 h after injection.Moreover, the EGFR-TK selectivity of [(125)I]PYK was confirmed by pretreatment experiments with specific EGFR-TK inhibitors.

View Article: PubMed Central - PubMed

Affiliation: Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Osaka, Takatsuki 569-1094, Japan.

ABSTRACT

Objective: Epidermal growth factor receptor tyrosine kinase (EGFR-TK) represents an attractive target for tumor diagnosis agents. Previously, radioiodinated 4-(3-iodophenoxy)-6,7-diethoxyquinazoline (PHY) was reported to possess good characteristics as a tumor imaging agent. We have explored the feasibility of developing tumor diagnosis ligands superior to radioiodinated PHY.

Methods: New phenoxyquinazoline derivatives were designed with various side chains introduced to the 6th position of PHY. The IC50 values of the new derivatives to interrupt EGFR-TK phosphorylation were evaluated and compared to well-known EGFR-TK inhibitors. Tumor uptake studies of the new (125)I-labeled derivatives were conducted with A431 tumor-bearing mice. Selectivity and binding characteristics were analyzed by in vitro blocking studies and a binding assay. Furthermore, SPECT/CT scans were performed using A431 tumor-bearing mice.

Results: Six quinazoline derivatives were designed and synthesized, and among these, 6a-d were found to have relatively high EGFR-TK inhibitory potency. In tumor uptake studies, [(125)I]6a ([(125)I]PYK) was found to have the highest tumor uptake and longest retention in tumors. In contrast, [(125)I]PYK was rapidly cleared from peripheral tissues, resulting in a high tumor-to-tissue ratio 24 h after injection. Moreover, the EGFR-TK selectivity of [(125)I]PYK was confirmed by pretreatment experiments with specific EGFR-TK inhibitors. Furthermore, [(125)I]PYK provided clear SPECT images of tumors.

Conclusions: Radioiodinated PYK, one of the newly synthesized quinazoline derivatives, was found to be a desirable ligand for EGFR-TK SPECT imaging. [(125)I]PYK showed high tumor accumulation and selective EGFR-TK binding and also succeeded in delivering high contrast imaging of tumors. These favorable characteristics of [(125)I]PYK suggest that the (123)I-labeled counterpart, [(123)I]PYK, would have great potential for diagnostic SPECT tumor imaging.

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Radioiodination of quinazoline derivatives
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Sch2: Radioiodination of quinazoline derivatives

Mentions: New radioiodinated quinazoline derivatives were prepared by an iododestannylation reaction under non-carrier-added conditions from the corresponding tributyltin precursor (7a–d) as outlined in scheme 2. Aqueous hydrogen peroxide (10 μL, 30 %) was added to a mixture of [125I]NaI (10 μL, 37.0 MBq, 74 TBq/mmol), 0.1 M HCl (25 μL) and the tributylstannyl precursor 7a–d (0.01 mg in 10 μL ethanol) in a sealed vial. After stirring for 10 min at room temperature, the reaction mixture was quenched with aqueous sodium bisulfite (0.1 mg in 10 μL). The mixture was isolated by HPLC using 0.1 M citrate buffer/MeOH or 0.1 M NaH2PO4 buffer/MeOH as the eluent at a flow rate of 3.0 mL/min. The fraction corresponding to [125I]6a–d was collected, and the solvent was removed in vacuo. Retention times, radiochemical yields, and radiochemical purities of the tracers were measured by HPLC.


A useful EGFR-TK ligand for tumor diagnosis with SPECT: development of radioiodinated 6-(3-morpholinopropoxy)-7-ethoxy-4-(3'-iodophenoxy)quinazoline.

Hirata M, Kanai Y, Naka S, Yoshimoto M, Kagawa S, Matsumuro K, Katsuma H, Yamaguchi H, Magata Y, Ohmomo Y - Ann Nucl Med (2013)

Radioiodination of quinazoline derivatives
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3672506&req=5

Sch2: Radioiodination of quinazoline derivatives
Mentions: New radioiodinated quinazoline derivatives were prepared by an iododestannylation reaction under non-carrier-added conditions from the corresponding tributyltin precursor (7a–d) as outlined in scheme 2. Aqueous hydrogen peroxide (10 μL, 30 %) was added to a mixture of [125I]NaI (10 μL, 37.0 MBq, 74 TBq/mmol), 0.1 M HCl (25 μL) and the tributylstannyl precursor 7a–d (0.01 mg in 10 μL ethanol) in a sealed vial. After stirring for 10 min at room temperature, the reaction mixture was quenched with aqueous sodium bisulfite (0.1 mg in 10 μL). The mixture was isolated by HPLC using 0.1 M citrate buffer/MeOH or 0.1 M NaH2PO4 buffer/MeOH as the eluent at a flow rate of 3.0 mL/min. The fraction corresponding to [125I]6a–d was collected, and the solvent was removed in vacuo. Retention times, radiochemical yields, and radiochemical purities of the tracers were measured by HPLC.

Bottom Line: Six quinazoline derivatives were designed and synthesized, and among these, 6a-d were found to have relatively high EGFR-TK inhibitory potency.In contrast, [(125)I]PYK was rapidly cleared from peripheral tissues, resulting in a high tumor-to-tissue ratio 24 h after injection.Moreover, the EGFR-TK selectivity of [(125)I]PYK was confirmed by pretreatment experiments with specific EGFR-TK inhibitors.

View Article: PubMed Central - PubMed

Affiliation: Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Osaka, Takatsuki 569-1094, Japan.

ABSTRACT

Objective: Epidermal growth factor receptor tyrosine kinase (EGFR-TK) represents an attractive target for tumor diagnosis agents. Previously, radioiodinated 4-(3-iodophenoxy)-6,7-diethoxyquinazoline (PHY) was reported to possess good characteristics as a tumor imaging agent. We have explored the feasibility of developing tumor diagnosis ligands superior to radioiodinated PHY.

Methods: New phenoxyquinazoline derivatives were designed with various side chains introduced to the 6th position of PHY. The IC50 values of the new derivatives to interrupt EGFR-TK phosphorylation were evaluated and compared to well-known EGFR-TK inhibitors. Tumor uptake studies of the new (125)I-labeled derivatives were conducted with A431 tumor-bearing mice. Selectivity and binding characteristics were analyzed by in vitro blocking studies and a binding assay. Furthermore, SPECT/CT scans were performed using A431 tumor-bearing mice.

Results: Six quinazoline derivatives were designed and synthesized, and among these, 6a-d were found to have relatively high EGFR-TK inhibitory potency. In tumor uptake studies, [(125)I]6a ([(125)I]PYK) was found to have the highest tumor uptake and longest retention in tumors. In contrast, [(125)I]PYK was rapidly cleared from peripheral tissues, resulting in a high tumor-to-tissue ratio 24 h after injection. Moreover, the EGFR-TK selectivity of [(125)I]PYK was confirmed by pretreatment experiments with specific EGFR-TK inhibitors. Furthermore, [(125)I]PYK provided clear SPECT images of tumors.

Conclusions: Radioiodinated PYK, one of the newly synthesized quinazoline derivatives, was found to be a desirable ligand for EGFR-TK SPECT imaging. [(125)I]PYK showed high tumor accumulation and selective EGFR-TK binding and also succeeded in delivering high contrast imaging of tumors. These favorable characteristics of [(125)I]PYK suggest that the (123)I-labeled counterpart, [(123)I]PYK, would have great potential for diagnostic SPECT tumor imaging.

Show MeSH
Related in: MedlinePlus