hydrazino-nicotinamide and tricine

Breast cancer is a malignant disease with high mortality rate among women in the world. It is necessary to diagnose breast cancer at the early stage before it metastasizes in patients.. The aim of this study is the evaluation of 99mTc-(tricine)-HYNIC-Lys-FROP for breast tumor imaging.. Lys-FROP peptide was labeled with 99mTc using HYNIC as chelator and tricine as co-ligand. Specific binding of this radiolabeled peptide on breast cancerous cell was assessed in different cell lines as well as in tumor-bearing mice.. HYNIC-Lys-FROP peptide was labeled with 99mTc at radiochemical purity more than 99%. It was observed high stability in normal saline and serum about 95%. The highest cellular uptake was observed in MCF-7 breast tumor cells treated with 99mTc-(tricine)-HYNIC-Lys-FROP as compared to other cell lines (lung, ovarian, T47D breast cancer cell lines). Biodistribution results in female MCF-7 tumor-bearing mice showed the relatively high tumor uptake and tumor-muscle ratio as 3.82 ± 0.66 after 15 min post-injection of 99mTc-(tricine)- HYNIC-Lys-FROP. Tumor uptake was reduced in mice that were co-injected with excess of unlabeled peptide to be 0.91 ± 0.08.. Findings showed this radiolabeled peptide is a promising candidate for tumor targeting and molecular imaging of breast cancer.

Topics: Animals; Breast Neoplasms; Cell Line, Tumor; Chelating Agents; Female; Glycine; Humans; Hydrazines; MCF-7 Cells; Mice, Nude; Niacinamide; Oligopeptides; Radionuclide Imaging; Radiopharmaceuticals; Technetium

Human epidermal growth factor receptor 2 (HER2) expression has been shown to be increased in several types of human tumours. In this study, for the imaging of HER2-related tumours, a modified RNA aptamer with HER2-specific targeting was labelled with (99m)Tc, by using hydrazino nicotinamide (HYNIC) as the chelator in the presence of tricine or ethylenediamine-N,N'-diacetic acid (EDDA) as the co-ligand. Stability testing of the radiolabelled aptamers in the serum was performed through SDS-PAGE. The aptamer-radionuclide conjugate was evaluated for its cellular HER2-specific binding in ovarian cancer cells (SKOV-3), and its biodistribution properties were assessed in normal and SKOV-3 tumour-bearing mice. In the presence of either tricine or EDDA, the HYNIC-RNA aptamers were labelled with (99m)Tc at a high yield and radiochemical purity. Cellular experiments confirmed the specific binding of the RNA aptamer to the HER2 receptor. In the animal biodistribution study, uptake of the EDDA-co-liganded (99m)Tc-HYNIC-RNA aptamer by the liver and spleen was remarkably lower than that of the aptamer with tricine. Tumours also showed a higher accumulation of radioactivity with the EDDA-co-liganded aptamer complex. This study demonstrated EDDA to be better than tricine for use as a co-ligand with the RNA aptamer, which can be a potential tool for the molecular imaging of HER2-overexpressing cancers.

Topics: Animals; Aptamers, Nucleotide; Cell Line, Tumor; Female; Glycine; Humans; Hydrazines; Indicators and Reagents; Ligands; Mice; Mice, Nude; Molecular Imaging; Niacinamide; Ovarian Neoplasms; Radiopharmaceuticals; Receptor, ErbB-2; RNA; Technetium; Tissue Distribution

Bombesin and its derivatives exhibit a high affinity for gastrin-releasing peptide receptor (GRPr), which is over-expressed in a variety of human cancers (prostate, pancreatic, lung, etc.). The aim of this study was to investigate the in vitro potential of the hydrazinonicotinamide (HYNIC)-Q-Litorin. (99m)Tc labeling was performed by using different co-ligands: tricine and ethylenediamine diacetic acid (EDDA). The radiochemical stability of radiolabeled peptide conjugates was checked at room temperature and in cysteine solution up to 24 h. The in vitro cell uptake of (99m)Tc-EDDA-HYNIC-Q-Litorin and (99m)Tc-tricine-HYNIC-Q-Litorin were evaluated on pancreatic tumor and control cell lines. Optimum specific activity and incubation time were determined for all the cell lines. The results showed that the cell uptake of the radiolabeled peptide conjugates in tumor cell lines were higher than in the control cell line. The findings of this study indicated the need for further development of in vivo study as a radiopharmaceutical for pancreatic tumor imaging.

Topics: Animals; Bombesin; Cell Line, Tumor; Cysteine; Edetic Acid; Glycine; Humans; Hydrazines; Ligands; Mice; Niacinamide; Oligopeptides; Organotechnetium Compounds; Radiopharmaceuticals; Rats; Receptors, Bombesin

Electrospray mass spectrometry (ESMS) of certain peptides labelled with (99m)Tc via hydrazinonicotinamide (HYNIC) with tricine as co-ligand shows one Tc-bound tricine, whereas typically two are observed. We speculated that this was due to coordination of a neighbouring histidine (His) or glutamate (Glu). To investigate this possibility, several short peptides incorporating lysine (HYNIC), with and without His and Glu at different positions in the sequence, were radiolabelled with (99m)Tc, using tricine, ethylenediaminediacetic acid (EDDA) and nicotinic acid as co-ligands. The products were examined by HPLC-ESMS, cysteine challenge and bovine serum albumin (BSA) challenge. Peptides with His nearby on either side of lysine (HYNIC) contained only one tricine and showed markedly enhanced structural homogeneity and stability to cysteine challenge and BSA binding, except those with His located at the N-terminus. Peptides without His, or with neighbouring N-terminal His, contained two tricines and were less stable to cysteine challenge and BSA binding. Glu participated in Tc-binding but did not enhance stability. We conclude that neighbouring His or Glu side chains coordinate to Tc and this could alter peptide or protein conformation. Inclusion of His in a neighbouring position to lysine (HYNIC) enhances stability, improves homogeneity and reduces the demand of the metal center for binding to additional co-ligands.

Topics: Animals; Cattle; Glutamic Acid; Glycine; Histidine; Hydrazines; Niacinamide; Peptides; Serum Albumin, Bovine; Spectrometry, Mass, Electrospray Ionization; Technetium