Preparation and evaluation of a new neurotensin analog labeled with 99mTc for targeted imaging of neurotensin receptor positive tumors

Radiopharmaceuticals for imaging and endoradiotherapy of neurotensin receptor‐positive tumors

“…28 Another HYNIC-bearing NT(8-13) analog with an additional glycine at the N-terminus and the Lys-for-Arg 9 and D-Tyr-for-Tyr 11 exchanges was reported (entry 21, Table 1). 29,30 In HT29 tumor-bearing mice, the tumor uptake of the 99m Tc-labeled peptide was 0.6 to 1.1 and 0.3 to 1.1%ID/g 1 and 4 hours after tracer injection, respectively. Blood clearance was slow, resulting in tumor-to-blood ratios of only 0.4 to 1 (1 hour p.i.)…”

“…Biodistribution was determined in healthy mice, showing predominantly renal excretion along with remarkable liver and intestinal uptake for both radiotracers . Another HYNIC‐bearing NT(8–13) analog with an additional glycine at the N‐terminus and the Lys‐for‐Arg 9 and D‐Tyr‐for‐Tyr 11 exchanges was reported (entry 21, Table ) . In HT29 tumor‐bearing mice, the tumor uptake of the 99m Tc‐labeled peptide was 0.6 to 1.1 and 0.3 to 1.1%ID/g 1 and 4 hours after tracer injection, respectively.…”

New neurotensin analogue radiolabeled by 99m‐technetium as a potential agent for tumor identification

“…[37] Tumor-to-non-target ratios of their analogue for tricine containing radiopeptide are lower than the ratios of our analogue, but ratios for tricine/EDDA containing radiopeptide are within the same range It is important to note that the tumor uptake of biomolecules is a complex phenomenon and not only impacted by biomolecules characteristic. In addition to biomolecule properties (such as tracer affinity, internalization, and metabolism), the tumor characteristics like tumor interstitial pressure, capillary extravazation, and targeted receptors shedding play an important role in this purpose.…”

“…In addition to biomolecule properties (such as tracer affinity, internalization, and metabolism), the tumor characteristics like tumor interstitial pressure, capillary extravazation, and targeted receptors shedding play an important role in this purpose. [38] Although very remarkable results in the tumor targeting of some neurotensin analogues labeled by 111-indum and 68-Gallium were reported by Alsoukr et al [2,19] , lower qualities associated with the tumor targeting via analogues labeled with 99m Tc [1,13,37] reveal that there is still a long way to explore a comprehensive biomolecule for the imaging of neurotensin-overexpressed tumors.…”

Tumor targeting with 99mTc radiolabeled peptides: Clinical application and recent development

“…Monomeric RGD derivatives tend to be quickly cleared from the blood and rapid tumor washout, whereas multimeric cyclic RGD peptides exhibit increased affinity and enhanced adhesion to target integrins due to an increase in multivalent sites. [143,144] For example, the 99m Tclabeled RGD-dimer peptide (E-[c(RGDfK)]2) has been [126] 99m Tc [HYNIC 0 , Gly 7 , Lys9, D-Tyr 11 ]-NT (7-13) Imaging of neurotensin receptor in nude mice bearing HT-29 tumor [181] 99m Tc (Na-His)Ac-NT (8)(9)(10)(11)(12)(13) Imaging of neurotensin receptor in nude mice bearing NCI-H446 SCLC tumor [182] 99m Tc [HYNIC 0 ,Gly 7 , Lys 9 , DTyr 11 ]-Neurotensin (7)(8)(9)(10)(11)(12)(13) Targeting of neurotensin receptor human HT-29 xenograft-bearing nude mice [183] 99m Tc-NT-VIII Imaging of neurotensin receptor in nude mice bearing HT-29 tumor [184] Note. NT, neurotensin.…”