Inhibitory effects of psoralen plus ultraviolet irradiation on human leukemic cell lines

: A semi-solid cell culture technique was used to study the sensitivity of K562, HL-60, and Raji leukemic cell lines to the inhibitory effect of psoralen plus ultraviolet irradiation. Results indicated that: 1) the inhibition rate of K562, HL-60, and Raji cell lines were 86%, 35%, and 36%, respectively; and 2) K562, HL-60, and Raji cell lines were treated with psoralen (20 micrograms.ml-1) for 1 h, then irradiated with ultraviolet (1 J/cm2) for 10 min, none of the leukemic cell lines showed colony or cluster formation. These suggested that the cytocidal effect of psoralen plus ultraviolet might be useful to eradicate the residual leukemic cells in the bone marrow transplantation.