Abstract
Photodynamic therapy is a method for treating cancer using drugs activated by light. A new compound, 5-aminolaevulinic acid (ALA), is a precursor of the active photosensitizer protoporphyrin IX (PpIX) and has fewer side-effects and much more transient phototoxicity than previous photosensitizers. Cell survival of ALA-mediated photodynamic therapy was measured in the J82 bladder cancer cell line, along with its mitomycin C-resistant counterpart J82/MMC. This demonstrated that mitomycin resistance is not cross-resistant to photodynamic therapy. There was also a suggestion that the mitomycin-resistant cells were more susceptible to photodynamic therapy than the parent cell line. Photodynamic therapy appeared to enhance the effect of mitomycin C, when mitomycin C was given first. This phenomenon was apparent for both drug-resistant and drug-sensitive cell lines. This suggests a possible role for combined mitomycin C and photodynamic therapy in superficial bladder tumours that have recurred despite intravesical cytotoxic drug treatment.
Highlights
The purpose of this study was to examine the enhanced activity that could be expected with these two treatment modalities, with particular respect to the possible effect of aminolaevulinic acid (ALA)-mediated photodynamic therapy with mitomycin C on a mitomycin-resistant cell line
The cells were maintained as monolayer cultures in 25-cm2 tissue culture flasks in Dulbecco's modified Eagle medium (DMEM) (Gibco) supplemented with 10% fetal calf serum (Gibco) and 1% penicillin and streptomycin (Sigma) at 37°C and 5% carbon dioxide
The ALA-induced fluorescence did not vary greatly between the J82 and J82/MMC cell lines, during the time course of ALA incubation used for subsequent photodynamic therapy (Figure 1)
Summary
The purpose of this study was to examine the enhanced activity that could be expected with these two treatment modalities, with particular respect to the possible effect of ALA-mediated photodynamic therapy with mitomycin C on a mitomycin-resistant cell line
Published Version
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