Growth inhibition of high-intensity focused ultrasound on hepatic cancer in vivo.
OBJECTIVE
To investigate the damaging effect of high-intensity focused ultrasound (HIFU) on cancer cells and the inhibitory effect on tumor growth.


METHODS
Murine H22 hepatic cancer cells were treated with HIFU at the same intensity for different lengths of time and at different intensities for the same length of time in vitro, the dead cancer cells were determined by trypan blue staining. Two groups of cancer cells treated with HIFU at the lowest and highest intensity were inoculated into mice. Tumor masses were removed and weighed after 2 wk, tumor growth in each group was confirmed pathologically.


RESULTS
The death rate of cancer cells treated with HIFU at 1 000 W/cm2 for 0.5, 1, 2, 4, 8, and 12 s was 3.11+/-1.21%, 13.37+/-2.56%, 38.84+/-3.68%, 47.22+/-5.76%, 87.55+/-7.32%, and 94.33+/-8.11%, respectively. A positive relationship between the death rates of cancer cells and the length of HIFU treatment time was found (r = 0.96, P<0.01). The death rate of cancer cells treated with HIFU at the intensity of 100, 200, 400, 600, 800, and 1 000 W/cm2 for 8 s was 26.31+/-3.26%, 31.00+/-3.87%, 41.97+/-5.86%, 72.23+/-8.12%, 94.90+/-8.67%, and 99.30+/-9.18%, respectively. A positive relationship between the death rates of cancer cells and the intensities of HIFU treatment was confirmed (r = 0.98, P<0.01). The cancer cells treated with HIFU at 1 000 W/cm2 for 8 s were inoculated into mice ex vivo. The tumor inhibitory rate was 90.35% compared to the control (P<0.01). In the experimental group inoculated with the cancer cells treated with HIFU at 1 000 W/cm2 for 0.5 s, the tumor inhibitory rate was 22.9% (P<0.01). By pathological examination, tumor growth was confirmed in 8 out of 14 mice (57.14%, 8/14) inoculated with the cancer cells treated with HIFU at 1 000 W/cm2 for 8 s, which was significantly lower than that in the control (100%, 15/15, P<0.05).


CONCLUSIONS
HIFU is effective on killing or damage of H22 hepatic cancer cells in vitro and on inhibiting tumor growth in mice ex vivo.
Wang
Xiu-Jie
XJ
Division of Experimental Oncology, Key Laboratory of Biotherapy of Human Diseases of Ministry of Education, PR China. xiujiewang@sina.com
Yuan
Shu-Lan
SL
Lu
Yan-Rong
YR
Zhang
Jie
J
Liu
Bo-Tao
BT
Zeng
Wen-Fu
WF
He
Yue-Ming
YM
Fu
Yu-Rui
YR
D000818:Animals; D006528:Carcinoma, Hepatocellular / Q000473:pathology / Q000628:therapy*; D016923:Cell Death; D002455:Cell Division; D045744:Cell Line, Tumor; D005260:Female; D008113:Liver Neoplasms / Q000473:pathology / Q000628:therapy*; D051379:Mice; D008807:Mice, Inbred BALB C; D014464:Ultrasonic Therapy / Q000379:methods*