[Growth-inhibiting effect of psoralen plus ultraviolet-A light therapy on K562 cells].
OBJECTIVE
To observe the effects of psoralen plus ultraviolet-A light (PUVA) on K562 cells and the relative mechanism.


METHODS
The effects of psoralen, ultraviolet-A light and PUVA on K562 cells were assayed by monotetrazolium test (MTT). DNA content was analyzed by flow cytometry (FCM). The apoptotic rates of K562 cells treated with 40 and 80 microg/ml psoralen for 24 and 48 hours were assayed by Annexin-V-FITC/PI reagent kit on FCM respectively. The ultrastructures of apoptotic cells were observed by a transmission electron microscope (TEM).


RESULTS
Either single psoralen therapy or single ultraviolet-A irradiation had inhibiting effect on K562 cells. The inhibiting effect of PUVA on K562 cells was stronger than that of the single psoralen therapy or single ultraviolet-A light irradiation (P<0.05). Apoptotic peak (AP) was detected by FCM. TEM test showed that K562 cells treated with PUVA were smaller, having condensed cell nucleus, assembled chromatin, disintegrated nucleus body and the majority of the cells appeared to be apoptotic conformation.


CONCLUSIONS
Psoralen has inhibiting effect on K562 cells, and the effect of PUVA is more significant. It is suggested that 10 min irradiation and 40 microg/ml terminal concentration of psoralen be probably the best choice for PUVA. The inhibiting effect of PUVA is due to apoptosis.
Zhang
De-Jie
DJ
Institute of Traditional Chinese Medicine and Hematology, People's Liberation Army, Dalian, Liaoning Province 116021, China. zdjdl210@yahoo.com.cn
Huang
Shi-Lin
SL
Chen
Nan-Nan
NN
Xiang
Yang
Y
Yang
Pei-Man
PM
Zhao
Jin-Yao
JY
D017209:Apoptosis / Q000187:drug effects*; D005363:Ficusin / Q000494:pharmacology; D006801:Humans; D020014:K562 Cells / Q000187:drug effects / Q000528:radiation effects; D011701:PUVA Therapy; D017319:Photosensitizing Agents / Q000494:pharmacology
D017319:Photosensitizing Agents; D005363:Ficusin