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Mono- and tri-cationic porphyrin-monoclonal antibody conjugates: photodynamic activity and mechanism of action.

Smith K, Malatesti N, Cauchon N, Hunting D, Lecomte R, van Lier JE, Greenman J, Boyle RW - Immunology (2010)

Bottom Line: In vitro, all conjugates retained the phototoxicity of the porphyrin and the immunoreactivity of the antibody.Mechanistic studies showed that conjugates formed from the mono- and tri-cationic porphyrin and anti-CD104 antibody mediated apoptosis following irradiation with non-thermal red light of 630 ± 15 nm wavelength.This effect was not observed with Photofrin or with conjugates formed from the same photosensitizers conjugated to an irrelevant antibody.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry and Centre for Biomedical Research, University of Hull, Kingston-upon-Hull, UK.

ABSTRACT
Two cationic porphyrins bearing an isothiocyanate group for conjugation to monocolonal antibodies have been synthesized. The two porphyrins conjugated efficiently to three monoclonal antibodies (anti-CD104, anti-CD146 and anti-CD326), which recognize antigens commonly over-expressed on a range of tumour cells. In vitro, all conjugates retained the phototoxicity of the porphyrin and the immunoreactivity of the antibody. Mechanistic studies showed that conjugates formed from the mono- and tri-cationic porphyrin and anti-CD104 antibody mediated apoptosis following irradiation with non-thermal red light of 630 ± 15 nm wavelength. In vivo antibody conjugates caused suppression of human LoVo tumour growth in immunodeficient NIH III mice, similar to the commercial photodynamic therapy (PDT) agent Photofrin, but at administered photosensitizer doses that were more than two orders of magnitude lower. Positron emission tomography (PET) following PDT showed a large, early increase in uptake of (18) fluorodeoxyglucose (FDG) by tumours treated with the anti-CD104 conjugates. This effect was not observed with Photofrin or with conjugates formed from the same photosensitizers conjugated to an irrelevant antibody.

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Related in: MedlinePlus

Structures of 5-(4-isothiocyanatophenyl)-15-(4-(3-N-methylpyridiniumyl)phenyl) porphyrin (porphyrin 1) and 5-(4-isothiocyanatophenyl)-10,15,20-tri(4-(3-N-methylpyridiniumyl)phenyl) porphyrin (porphyrin 2).
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fig01: Structures of 5-(4-isothiocyanatophenyl)-15-(4-(3-N-methylpyridiniumyl)phenyl) porphyrin (porphyrin 1) and 5-(4-isothiocyanatophenyl)-10,15,20-tri(4-(3-N-methylpyridiniumyl)phenyl) porphyrin (porphyrin 2).

Mentions: Conjugation was carried out as described previously.11 Briefly, the antibody and porphyrin 1 or 2 (Fig. 1) were agitated gently at room temperature for 1 hr, while being protected from light. Conjugates were purified using Sephadex G25 columns (Amersham, Buckinghamshire, UK) and eluted with phosphate-buffered saline (PBS), pH 7·4. The degree of labelling (the number of moles of porphyrin conjugated per mole of antibody) was calculated using spectroscopic methods.12 Immunoconjugates were centrifuged at 13 000 g for 10 min to remove any traces of aggregates, and then the supernatant was filtered through a 0·2-μm syringe filter prior to storage at 4° or, for long-term storage, at −20°.


Mono- and tri-cationic porphyrin-monoclonal antibody conjugates: photodynamic activity and mechanism of action.

Smith K, Malatesti N, Cauchon N, Hunting D, Lecomte R, van Lier JE, Greenman J, Boyle RW - Immunology (2010)

Structures of 5-(4-isothiocyanatophenyl)-15-(4-(3-N-methylpyridiniumyl)phenyl) porphyrin (porphyrin 1) and 5-(4-isothiocyanatophenyl)-10,15,20-tri(4-(3-N-methylpyridiniumyl)phenyl) porphyrin (porphyrin 2).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3045661&req=5

fig01: Structures of 5-(4-isothiocyanatophenyl)-15-(4-(3-N-methylpyridiniumyl)phenyl) porphyrin (porphyrin 1) and 5-(4-isothiocyanatophenyl)-10,15,20-tri(4-(3-N-methylpyridiniumyl)phenyl) porphyrin (porphyrin 2).
Mentions: Conjugation was carried out as described previously.11 Briefly, the antibody and porphyrin 1 or 2 (Fig. 1) were agitated gently at room temperature for 1 hr, while being protected from light. Conjugates were purified using Sephadex G25 columns (Amersham, Buckinghamshire, UK) and eluted with phosphate-buffered saline (PBS), pH 7·4. The degree of labelling (the number of moles of porphyrin conjugated per mole of antibody) was calculated using spectroscopic methods.12 Immunoconjugates were centrifuged at 13 000 g for 10 min to remove any traces of aggregates, and then the supernatant was filtered through a 0·2-μm syringe filter prior to storage at 4° or, for long-term storage, at −20°.

Bottom Line: In vitro, all conjugates retained the phototoxicity of the porphyrin and the immunoreactivity of the antibody.Mechanistic studies showed that conjugates formed from the mono- and tri-cationic porphyrin and anti-CD104 antibody mediated apoptosis following irradiation with non-thermal red light of 630 ± 15 nm wavelength.This effect was not observed with Photofrin or with conjugates formed from the same photosensitizers conjugated to an irrelevant antibody.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry and Centre for Biomedical Research, University of Hull, Kingston-upon-Hull, UK.

ABSTRACT
Two cationic porphyrins bearing an isothiocyanate group for conjugation to monocolonal antibodies have been synthesized. The two porphyrins conjugated efficiently to three monoclonal antibodies (anti-CD104, anti-CD146 and anti-CD326), which recognize antigens commonly over-expressed on a range of tumour cells. In vitro, all conjugates retained the phototoxicity of the porphyrin and the immunoreactivity of the antibody. Mechanistic studies showed that conjugates formed from the mono- and tri-cationic porphyrin and anti-CD104 antibody mediated apoptosis following irradiation with non-thermal red light of 630 ± 15 nm wavelength. In vivo antibody conjugates caused suppression of human LoVo tumour growth in immunodeficient NIH III mice, similar to the commercial photodynamic therapy (PDT) agent Photofrin, but at administered photosensitizer doses that were more than two orders of magnitude lower. Positron emission tomography (PET) following PDT showed a large, early increase in uptake of (18) fluorodeoxyglucose (FDG) by tumours treated with the anti-CD104 conjugates. This effect was not observed with Photofrin or with conjugates formed from the same photosensitizers conjugated to an irrelevant antibody.

Show MeSH
Related in: MedlinePlus