Limits...
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.

Show MeSH

Related in: MedlinePlus

CORL23 and LoVo cells were treated with LD25, LD50 and LD75 concentrations of anti-CD104-porphyrin 1 and incubated for 6 hr prior to irradiation at 15 J/cm2. Cells in the lower left quadrant are viable, those in the lower right quadrant are apoptotic and those in the upper right quadrant are necrotic; 10 000 events were analysed for each sample.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3045661&req=5

fig03: CORL23 and LoVo cells were treated with LD25, LD50 and LD75 concentrations of anti-CD104-porphyrin 1 and incubated for 6 hr prior to irradiation at 15 J/cm2. Cells in the lower left quadrant are viable, those in the lower right quadrant are apoptotic and those in the upper right quadrant are necrotic; 10 000 events were analysed for each sample.

Mentions: The mechanism of cell death is highly relevant to the treatment of some cancers, as the promotion of apoptotic, rather than necrotic, mechanisms can reduce scarring and lead to regeneration of functional tissue. An early stage of apoptosis is the ‘flipping’ of phosphatidyl serine (PS) from the inner to the outer side of the plasma membrane, which is detectable with Annexin V-FITC. To investigate the possible mechanisms of cell death, cells were incubated with anti-CD104-porphyrin 1 immunoconjugates for 6 hr before irradiation with 15 J/cm2 light. Cell death was then assessed for Annexin-V/propidium iodide binding 15 min post-irradiation (Fig. 3). At the LD25 concentration the cells behaved similarly; however, from LD50 and above the LoVo cells were more sensitive to the effects of PDT, with a greater percentage in the upper right (apoptotic and necrotic) quadrant. At LD75 LoVo cells appeared markedly more sensitive to killing, with the vast majority of cells in the upper right quadrant compared with 45% of CORL23. The latter cell type also showed 30% in the lower right (apoptotic) quadrant at the highest drug dose, whereas the LoVo cells had ‘progressed’ to necrosis. A similar trend was seen with the other immunoconjugates, with LoVo showing higher levels of necrotic cell death; surprisingly, the anti-CD146 conjugate also showed high levels of non-specific toxicity (data not shown).


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)

CORL23 and LoVo cells were treated with LD25, LD50 and LD75 concentrations of anti-CD104-porphyrin 1 and incubated for 6 hr prior to irradiation at 15 J/cm2. Cells in the lower left quadrant are viable, those in the lower right quadrant are apoptotic and those in the upper right quadrant are necrotic; 10 000 events were analysed for each sample.
© Copyright Policy
Related In: Results  -  Collection

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

fig03: CORL23 and LoVo cells were treated with LD25, LD50 and LD75 concentrations of anti-CD104-porphyrin 1 and incubated for 6 hr prior to irradiation at 15 J/cm2. Cells in the lower left quadrant are viable, those in the lower right quadrant are apoptotic and those in the upper right quadrant are necrotic; 10 000 events were analysed for each sample.
Mentions: The mechanism of cell death is highly relevant to the treatment of some cancers, as the promotion of apoptotic, rather than necrotic, mechanisms can reduce scarring and lead to regeneration of functional tissue. An early stage of apoptosis is the ‘flipping’ of phosphatidyl serine (PS) from the inner to the outer side of the plasma membrane, which is detectable with Annexin V-FITC. To investigate the possible mechanisms of cell death, cells were incubated with anti-CD104-porphyrin 1 immunoconjugates for 6 hr before irradiation with 15 J/cm2 light. Cell death was then assessed for Annexin-V/propidium iodide binding 15 min post-irradiation (Fig. 3). At the LD25 concentration the cells behaved similarly; however, from LD50 and above the LoVo cells were more sensitive to the effects of PDT, with a greater percentage in the upper right (apoptotic and necrotic) quadrant. At LD75 LoVo cells appeared markedly more sensitive to killing, with the vast majority of cells in the upper right quadrant compared with 45% of CORL23. The latter cell type also showed 30% in the lower right (apoptotic) quadrant at the highest drug dose, whereas the LoVo cells had ‘progressed’ to necrosis. A similar trend was seen with the other immunoconjugates, with LoVo showing higher levels of necrotic cell death; surprisingly, the anti-CD146 conjugate also showed high levels of non-specific toxicity (data not shown).

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