Objective: To investigate the effect of high intensity focused ultrasound (HIFU) treatment on the metastasis of melanoma cells in a mouse model of melanoma.
Methods: Mouse melanoma cells B16-F10 were injected subcutaneously to construct a mouse melanoma subcutaneous xenograft tumor model; HIFU treatment was performed when the longest diameter of the tumor was 7-10 mm, and an experimental control group was set up (irradiation of tumor-bearing mice HIFU but keep the power source switch of the treatment head turned off, that is, the fake photo group); measure the long and short diameters of the tumor every 3 days after treatment, observe for 3 weeks, draw the tumor curve, calculate the survival rate and metastasis rate, and quantify it through real-time fluorescence The relative expression of three markers of melanoma cells in the blood was measured by PCR to monitor the number of circulating melanoma cells in the blood. They are melanoma-associated antigen A3 (MAGE-A3) and melanoma antigen recognized by T cell 1 (MART1). ) And homologously transformed into the pair-box gene transcription factor PAX3); 14 days after HIFU treatment, B16-F10 cells were transplanted again by tail vein injection to observe the lung metastasis rate.
Results: (1) The respective median survival time and 95% confidence interval (CI): the fake photograph group was 19.00 d and 17.14-20.86 d, respectively, and the HIFU group was 26.00 d and 24.76-27.25 d, respectively, and the survival rate was different. Show (P<0.01); From the 20th day after treatment, the tumor volume of the two groups of mice was significantly different. From the 20th day after HIFU treatment, including the 23rd and 26th days after treatment, the tumor volume of the irradiated mice (P<0.05); (2) The real-time fluorescent quantitative PCR results showed that the three indexes of MAGE-A3, MART1 and PAX3 in the HIFU group were significantly lower than those of the fake photo group (P <0.05), on the 14th day after treatment, the expression of MAGE-A3 was still significantly lower than that of the fake photo group (P<0.05); (3) The same tumor cells were transplanted again through the tail vein on the 14th day after HIFU treatment, the HIFU group The number of lung metastases was significantly lower than that in the sham group (P<0.05), and the tumor metastasis inhibition rate was 42.4%.
Conclusion: HIFU treatment can inhibit the occurrence of melanoma cell metastasis in vivo. The mechanism may involve reducing the shedding of tumor cells from the primary tumor and the ability of tumor cells to colonize the lung.