Objectives. The goal of this research was to assess whether methoxypso
ralen compounds in combination with ultraviolet light were effective i
n preventing cellular proliferation in an in vitro model of human tran
sitional cell carcinoma.Methods. Three methoxypsoralen compounds, 5-me
thoxypsoralen (5-MOP), 8-methoxypsoralen (8-MOP), and 4'-aminomethyl 4
,5'-8'-trimethylpsoralen (AMT), were added in vitro to T-24 transition
al cell carcinoma cells. Psoralens directly bind to DNA, cross-linking
the strands when exposed to ultraviolet light and thereby prevent cel
lular division. Results. In vitro activity was demonstrated utilizing
AMT and ultraviolet radiation at 320 to 340 nm, preventing cellular pr
oliferation in T-24 transitional cell carcinoma. Conclusions. Methoxyp
soralen compounds in combination with ultraviolet light are effective
in preventing proliferation of bladder carcinoma cells in vitro. This
therapy may prove to be effective in clinical early stage transitional
cell carcinoma and warrants further assessment.