The relationship between the remnant tumor and the epithelial-mesenchymal transition after cryoablation:an experimental study / 介入放射学杂志

ABSTRACT

Objective To investigate the effect of incomplete cryoablation on the biological behavior of prostatic cancer RM-1 cells and its mechanism.Methods RM-1 cells of prostatic cancer were placed in -20℃ icebox to be frozen for 5 min.After the recovery of the cell state,the RM-1 cells were frozen again for 10 min and 15 min successively.After culture for one day,the cellular morphology was microscopically examined.A total of 20 C57/BL mice were used to establish the tumor-bearing models,which were randomly and equally divided into the control group and the incomplete cryoablation group with 10 mice in each group.At scheduled time points the tumor lesion size was measured for all mice.The mice were sacrificed at 14 days,the lung tissues were collected and were stained with lE;the numbers of metastatic lesions in the lung were calculated.Transwell assay was used to test the cell migration and invasion,immuno-blotting method was adopted to determine the epithelial-mesenchymal transition-related (EMT-related) protein expression level,and the enzyme-linked immunosorbent assay (ELISA) was employed to check the secretion volume of transforming growth factor-beta (TGF-β).Results After incomplete cryoablation,RM-1 cells became disorderly arranged,their morphology was changed,and antenna structure might be formed.At 3 and 7 days after cryoablation,the tumor size in the incomplete cryoablation group was slightly smaller than that in the control group,but only the difference at 7 days after cryoablation was statistically significant between the two groups (P=0.019).At 10 and 14 days after cryoablation,the tumor volume of the two groups was almost equal.The pulmonary metastatic lesions in the incomplete cryoablation group were obviously much more than those in the control group (P＜0.001).Transwell assay indicated that the cell migration and invasion ability in the incomplete cryoablation group was stronger than that in the control group (P＜0.05).Immuno-blotting test revealed that,when compared with the control group,in the incomplete cryoablation group the expressions of N-cadherin,MMP-9 and Vimentin were up-regulated,while the expression of E-cadherin was downregulated.ELISA test showed that increased secretion of TGF-β was observed in the incomplete cryoablation group.Conclusion Incomplete cryoablation can enhance the migration and invasion ability of RM-1 cells,increase the number of pulmonary metastatic lesions in tumor-bearing mice,and affect the EMT-related protein expression level.