Strategies for labelling branched polypeptides with a poly(L‐lysine) backbone with radioiodines (123I, 125I, 131I) and radiometals (111In, 51Cr) for biodistribution studies and radiopharmaceutical development

Malcolm V. Pimm, Sandra J. Gribben, G. Mező, F. Hudecz

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11 Citations (Scopus)

Abstract

Methods have been developed for radiolabelling synthetic branched polypeptides, these being based on a poly(L‐lysine) backbone with short side chains of three DL‐alanine residues and one other amino acid at the end of the branches (MW ∼45‐100 kDa). Labelling has been carried out with gamma emitting radionuclides suitable for use in biodistribution studies or for gamma scintigraphy. Labelling with 125I was achieved by reaction of the polypeptides' terminal amino groups with pre‐iodinated Bolton and Hunter Reagent (N‐Succinimidyl 3‐(4‐hydroxy‐5‐[125I]iodophenyl)propionate). Alternatively, polypeptides were reacted with non‐labelled Bolton and Hunter reagent, which could subsequently be iodinated with 123I, 125I or 131I by oxidative incorporation from [123I]Nal, [125I]Nal, or [123I]Nal. For labelling with radiometals, the polypeptides' terminal amino groups were reacted with diethylenetriaminepentaacetic acid (DTPA) anhydride, and the conjugated DTPA subsequently labelled with 111In or 51Cr by chelation. An amphoteric polypeptide, having terminal glutamic acid residues on its side chains (EAK), and a polycationic polypeptide, with terminal D‐lysine (D‐KAK) were labelled in these ways. In addition EAK previously conjugated to the cis‐aconityl derivative of daunomycin (EAK‐cAD) was similarly labelled. Gel permeation chromatography on Sephacryl S‐300, which was possible with the amphoteric EAK, showed virtually identical elution profiles with 123I, 125I 131I, 111In and 51Cr labelled EAK and its cAD conjugate. Biodistribution studies in mice showed prolonged blood survival of the radionuclide of 125I, 111In or 51Cr labelled EAK and EAK‐cAD. There were, however, differences in organ levels of the radionuclides. Generally kidney, spleen and liver levels of radiometals were higher than those of radioiodine, while levels in the gastrointestinal tract were higher with radioiodine. D‐KAK labelled with any of the three radionuclides was cleared rapidly from the blood, high levels of all tracers being found in spleen, liver, kidney and lung.

Original languageEnglish
Pages (from-to)157-172
Number of pages16
JournalJournal of Labelled Compounds and Radiopharmaceuticals
Volume36
Issue number2
DOIs
Publication statusPublished - 1995

Fingerprint

Radiopharmaceuticals
Labeling
Radioisotopes
Peptides
Liver
Blood
Spleen
Kidney
Daunorubicin
Acids
Anhydrides
Propionates
Gel permeation chromatography
Chelation
Radionuclide Imaging
Gel Chromatography
Gastrointestinal Tract
Glutamic Acid
Derivatives
Amino Acids

Keywords

  • In
  • Cr
  • Biodistribution
  • Branched polypeptides
  • Poly‐(L‐lysine)
  • Radioiodine

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry
  • Radiology Nuclear Medicine and imaging
  • Drug Discovery
  • Spectroscopy
  • Organic Chemistry

Cite this

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title = "Strategies for labelling branched polypeptides with a poly(L‐lysine) backbone with radioiodines (123I, 125I, 131I) and radiometals (111In, 51Cr) for biodistribution studies and radiopharmaceutical development",
abstract = "Methods have been developed for radiolabelling synthetic branched polypeptides, these being based on a poly(L‐lysine) backbone with short side chains of three DL‐alanine residues and one other amino acid at the end of the branches (MW ∼45‐100 kDa). Labelling has been carried out with gamma emitting radionuclides suitable for use in biodistribution studies or for gamma scintigraphy. Labelling with 125I was achieved by reaction of the polypeptides' terminal amino groups with pre‐iodinated Bolton and Hunter Reagent (N‐Succinimidyl 3‐(4‐hydroxy‐5‐[125I]iodophenyl)propionate). Alternatively, polypeptides were reacted with non‐labelled Bolton and Hunter reagent, which could subsequently be iodinated with 123I, 125I or 131I by oxidative incorporation from [123I]Nal, [125I]Nal, or [123I]Nal. For labelling with radiometals, the polypeptides' terminal amino groups were reacted with diethylenetriaminepentaacetic acid (DTPA) anhydride, and the conjugated DTPA subsequently labelled with 111In or 51Cr by chelation. An amphoteric polypeptide, having terminal glutamic acid residues on its side chains (EAK), and a polycationic polypeptide, with terminal D‐lysine (D‐KAK) were labelled in these ways. In addition EAK previously conjugated to the cis‐aconityl derivative of daunomycin (EAK‐cAD) was similarly labelled. Gel permeation chromatography on Sephacryl S‐300, which was possible with the amphoteric EAK, showed virtually identical elution profiles with 123I, 125I 131I, 111In and 51Cr labelled EAK and its cAD conjugate. Biodistribution studies in mice showed prolonged blood survival of the radionuclide of 125I, 111In or 51Cr labelled EAK and EAK‐cAD. There were, however, differences in organ levels of the radionuclides. Generally kidney, spleen and liver levels of radiometals were higher than those of radioiodine, while levels in the gastrointestinal tract were higher with radioiodine. D‐KAK labelled with any of the three radionuclides was cleared rapidly from the blood, high levels of all tracers being found in spleen, liver, kidney and lung.",
keywords = "In, Cr, Biodistribution, Branched polypeptides, Poly‐(L‐lysine), Radioiodine",
author = "Pimm, {Malcolm V.} and Gribben, {Sandra J.} and G. Mező and F. Hudecz",
year = "1995",
doi = "10.1002/jlcr.2580360208",
language = "English",
volume = "36",
pages = "157--172",
journal = "Journal of Labelled Compounds and Radiopharmaceuticals",
issn = "0362-4803",
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TY - JOUR

T1 - Strategies for labelling branched polypeptides with a poly(L‐lysine) backbone with radioiodines (123I, 125I, 131I) and radiometals (111In, 51Cr) for biodistribution studies and radiopharmaceutical development

AU - Pimm, Malcolm V.

AU - Gribben, Sandra J.

AU - Mező, G.

AU - Hudecz, F.

PY - 1995

Y1 - 1995

N2 - Methods have been developed for radiolabelling synthetic branched polypeptides, these being based on a poly(L‐lysine) backbone with short side chains of three DL‐alanine residues and one other amino acid at the end of the branches (MW ∼45‐100 kDa). Labelling has been carried out with gamma emitting radionuclides suitable for use in biodistribution studies or for gamma scintigraphy. Labelling with 125I was achieved by reaction of the polypeptides' terminal amino groups with pre‐iodinated Bolton and Hunter Reagent (N‐Succinimidyl 3‐(4‐hydroxy‐5‐[125I]iodophenyl)propionate). Alternatively, polypeptides were reacted with non‐labelled Bolton and Hunter reagent, which could subsequently be iodinated with 123I, 125I or 131I by oxidative incorporation from [123I]Nal, [125I]Nal, or [123I]Nal. For labelling with radiometals, the polypeptides' terminal amino groups were reacted with diethylenetriaminepentaacetic acid (DTPA) anhydride, and the conjugated DTPA subsequently labelled with 111In or 51Cr by chelation. An amphoteric polypeptide, having terminal glutamic acid residues on its side chains (EAK), and a polycationic polypeptide, with terminal D‐lysine (D‐KAK) were labelled in these ways. In addition EAK previously conjugated to the cis‐aconityl derivative of daunomycin (EAK‐cAD) was similarly labelled. Gel permeation chromatography on Sephacryl S‐300, which was possible with the amphoteric EAK, showed virtually identical elution profiles with 123I, 125I 131I, 111In and 51Cr labelled EAK and its cAD conjugate. Biodistribution studies in mice showed prolonged blood survival of the radionuclide of 125I, 111In or 51Cr labelled EAK and EAK‐cAD. There were, however, differences in organ levels of the radionuclides. Generally kidney, spleen and liver levels of radiometals were higher than those of radioiodine, while levels in the gastrointestinal tract were higher with radioiodine. D‐KAK labelled with any of the three radionuclides was cleared rapidly from the blood, high levels of all tracers being found in spleen, liver, kidney and lung.

AB - Methods have been developed for radiolabelling synthetic branched polypeptides, these being based on a poly(L‐lysine) backbone with short side chains of three DL‐alanine residues and one other amino acid at the end of the branches (MW ∼45‐100 kDa). Labelling has been carried out with gamma emitting radionuclides suitable for use in biodistribution studies or for gamma scintigraphy. Labelling with 125I was achieved by reaction of the polypeptides' terminal amino groups with pre‐iodinated Bolton and Hunter Reagent (N‐Succinimidyl 3‐(4‐hydroxy‐5‐[125I]iodophenyl)propionate). Alternatively, polypeptides were reacted with non‐labelled Bolton and Hunter reagent, which could subsequently be iodinated with 123I, 125I or 131I by oxidative incorporation from [123I]Nal, [125I]Nal, or [123I]Nal. For labelling with radiometals, the polypeptides' terminal amino groups were reacted with diethylenetriaminepentaacetic acid (DTPA) anhydride, and the conjugated DTPA subsequently labelled with 111In or 51Cr by chelation. An amphoteric polypeptide, having terminal glutamic acid residues on its side chains (EAK), and a polycationic polypeptide, with terminal D‐lysine (D‐KAK) were labelled in these ways. In addition EAK previously conjugated to the cis‐aconityl derivative of daunomycin (EAK‐cAD) was similarly labelled. Gel permeation chromatography on Sephacryl S‐300, which was possible with the amphoteric EAK, showed virtually identical elution profiles with 123I, 125I 131I, 111In and 51Cr labelled EAK and its cAD conjugate. Biodistribution studies in mice showed prolonged blood survival of the radionuclide of 125I, 111In or 51Cr labelled EAK and EAK‐cAD. There were, however, differences in organ levels of the radionuclides. Generally kidney, spleen and liver levels of radiometals were higher than those of radioiodine, while levels in the gastrointestinal tract were higher with radioiodine. D‐KAK labelled with any of the three radionuclides was cleared rapidly from the blood, high levels of all tracers being found in spleen, liver, kidney and lung.

KW - In

KW - Cr

KW - Biodistribution

KW - Branched polypeptides

KW - Poly‐(L‐lysine)

KW - Radioiodine

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U2 - 10.1002/jlcr.2580360208

DO - 10.1002/jlcr.2580360208

M3 - Article

VL - 36

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EP - 172

JO - Journal of Labelled Compounds and Radiopharmaceuticals

JF - Journal of Labelled Compounds and Radiopharmaceuticals

SN - 0362-4803

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