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Photodynamic therapy and photochemical internalisation of human Head and Neck cancer cells in vitro: comparison among Foscan, Foslip and Fospeg.

(2013) Peng, W. (Wei)

Background:
Photodynamic therapy (PDT) of cancer is a clinically established modality with a light-activated photosensitiser. The photosensitiser, meta-tetrahydroxyphenyl chlorin (mTHPC) in a dissolved formulation known as Foscan, has officially been approved by EU for the PDT treatment of Head and Neck cancer. However, there is still a need to improve this modality. Furthermore, PDT has recently been introduced to release anticancer drugs that are entrapped in the endo/lysosomal vesicles of cancer cells, so that the drugs can reach their therapeutic target sites of cancer cells. This new approach is referred to as Photochemical Internalisation (PCI). However, no officially approved photosensitisers have been studied for the PCI technology.
Aims:
(1) To compare 3 formulations of mTHPC with respect to PDT efficacy in two human Head and Neck cancer cell lines scc-U2 and scc-U8 in vitro; and (2) to explore the possibility of using the 3 formulations of mTHPC to induce a PCI effect of the chemotherapeutic agent Bleomycin (BLM) in the cell lines in vitro.
Materials and methods:
mTHPC as a photosensitiser in a dissolved formulation known as Foscan, encapsulated into conventional liposomes as Foslip and into pegylated liposomes as Fospeg was include in this study. The uptake of the 3 formulations of mTHPC by the scc-U8 cells as a function of concentrations was studied by flow cytometry. Efficacy of PDT was compared among Foscan, Foslip and Fospeg in the scc-U2 and scc-U8 cells in vitro and the cell survival was measured with the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium assay. In addition, the mode of cell death was investigated with flow cytometry using the staining of Annexin-V for apoptosis and propidium iodide for necrosis. Further, PCI effects of BLM with the 3 formulations of mTHPC were studied with the ‘light-after’ or ‘light before’ protocol. The Student t test was used to analyse the differences in various treatment groups using the software of SigmaPlot-11 and a p-value of <0.05 was considered statistically significant.
Results and discussion:
Foscan was taken up by the cells much faster than Foslip and Fospeg, probably via a passive diffuse pathway; while Foslip and Fospeg through endocytosis. PDT with Foslip and Fospeg killed significantly more cells than Foscan (p<0.05) in the cell lines. Foscan-PDT, however, induced more apoptosis. With the conventional ‘light after’ protocol no PCI effect of BLM was found with the 3 drugs in the cell lines; while the use of the ‘light before’ protocol with Foslip and Fospeg did produce a significant PCI effect of BLM on the cell killing (p<0.05). A possible mechanism for this finding was discussed.
Conclusions:
PDT with Foslip and Fospeg is more efficient than Foscan at killing cancer cells. The ‘light after’ PCI protocol does not produce a PCI effect of BLM, but the ‘light before’ PCI protocol with Foslip and Fospeg induces a significant PCI effect of BLM on the cell killing. The findings of this study suggest that Foslip and Fospeg would be good candidates for further developing both PDT and PCI techniques.
Presentation:
This study was selected as an oral presentation in the European Conference on Biomedical Optics, 12-16 May, 2013 in Munich, Germany.





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ID 1732
Moeder ID 1544
Volgorde Peng, W. (Wei)
Naam PengW
Publiceren yes
OAI-naam Student_thesis
Path root/geneeskunde/2013/PengW/
Gemaakt op: 2013-10-30 08:59:24
Gemodificeerd op: 2013-10-30 08:59:24
Digitaal ID 5270ca8a599cd
Afstudeerrichting opleiding/afstudeerrichting 1
Studierichting Studierichting 1
Titel Photodynamic therapy and photochemical internalisation of human Head and Neck cancer cells in vitro: comparison among Foscan, Foslip and Fospeg.
Ruilverkeer mogelijk no
Printen in opdracht no
Aantal pagina's 28
Publicatiejaar 2013
Taal en
Engelse samenvatting Background:
Photodynamic therapy (PDT) of cancer is a clinically established modality with a light-activated photosensitiser. The photosensitiser, meta-tetrahydroxyphenyl chlorin (mTHPC) in a dissolved formulation known as Foscan, has officially been approved by EU for the PDT treatment of Head and Neck cancer. However, there is still a need to improve this modality. Furthermore, PDT has recently been introduced to release anticancer drugs that are entrapped in the endo/lysosomal vesicles of cancer cells, so that the drugs can reach their therapeutic target sites of cancer cells. This new approach is referred to as Photochemical Internalisation (PCI). However, no officially approved photosensitisers have been studied for the PCI technology.
Aims:
(1) To compare 3 formulations of mTHPC with respect to PDT efficacy in two human Head and Neck cancer cell lines scc-U2 and scc-U8 in vitro; and (2) to explore the possibility of using the 3 formulations of mTHPC to induce a PCI effect of the chemotherapeutic agent Bleomycin (BLM) in the cell lines in vitro.
Materials and methods:
mTHPC as a photosensitiser in a dissolved formulation known as Foscan, encapsulated into conventional liposomes as Foslip and into pegylated liposomes as Fospeg was include in this study. The uptake of the 3 formulations of mTHPC by the scc-U8 cells as a function of concentrations was studied by flow cytometry. Efficacy of PDT was compared among Foscan, Foslip and Fospeg in the scc-U2 and scc-U8 cells in vitro and the cell survival was measured with the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium assay. In addition, the mode of cell death was investigated with flow cytometry using the staining of Annexin-V for apoptosis and propidium iodide for necrosis. Further, PCI effects of BLM with the 3 formulations of mTHPC were studied with the ‘light-after’ or ‘light before’ protocol. The Student t test was used to analyse the differences in various treatment groups using the software of SigmaPlot-11 and a p-value of <0.05 was considered statistically significant.
Results and discussion:
Foscan was taken up by the cells much faster than Foslip and Fospeg, probably via a passive diffuse pathway; while Foslip and Fospeg through endocytosis. PDT with Foslip and Fospeg killed significantly more cells than Foscan (p<0.05) in the cell lines. Foscan-PDT, however, induced more apoptosis. With the conventional ‘light after’ protocol no PCI effect of BLM was found with the 3 drugs in the cell lines; while the use of the ‘light before’ protocol with Foslip and Fospeg did produce a significant PCI effect of BLM on the cell killing (p<0.05). A possible mechanism for this finding was discussed.
Conclusions:
PDT with Foslip and Fospeg is more efficient than Foscan at killing cancer cells. The ‘light after’ PCI protocol does not produce a PCI effect of BLM, but the ‘light before’ PCI protocol with Foslip and Fospeg induces a significant PCI effect of BLM on the cell killing. The findings of this study suggest that Foslip and Fospeg would be good candidates for further developing both PDT and PCI techniques.
Presentation:
This study was selected as an oral presentation in the European Conference on Biomedical Optics, 12-16 May, 2013 in Munich, Germany.
Onderwijsinstelling Medical Sciences
Type embargo abstract openbaar, scriptie op aanvraag
Auteur(s) Peng, W. (Wei)
UMCG begeleider(s) Witjes, Max J.H., MD, DDS, PhD
Auteur(s) Peng, W. (Wei)
UMCG begeleider(s) Witjes, Max J.H., MD, DDS, PhD


 
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