Cryoablation induced the change of TGF-β pathway in CWR-22RV prostate cancer cell line

Purpose: To assess the efficacy of TGF-β pathway in the CWR-22RV prostate cancer cell line induced by cryoablation.

Materials and methods: According to the district in the tumor following cryoablation, the CWR-22RV prostate cancer cells were divided into four groups to construct the freezing model of prostate cancer in cell level: Group A, control cells (the uncovered district), Group B, freezing cells (sub-lethal district away from necrosis), Group C, control cells cultured with 1640 and necrosis supernatant and Group D, freezing cells cultured with 1640 and necrosis supernatant (sub-lethal district close to necrosis). Cell apoptosis was observed by flow cytometry analysis 24 h later. Then supernatant in four groups was extracted to test the concentration of TGF-β by ELISA at the time points of 5, 10, 20, 36, and 48 h. At the same time, intracellular TGF-β, Smad2/3, Smad4 of four groups were detected by Western blot at the time point of 10 h.

Results: In aspect of apoptosis, groups B-D have higher apoptosis rate than group A, group D has more apoptosis cells than group B and C. This was verified that the model was successful. Moreover, we found that group C has higher delayed apoptosis rate than group A, and group D has higher early apoptosis rate than other groups (P<0.05); compared with group A, C, D, group B has less TGF-β (P<0.05). Group C secrets more TGF-β than that in group A (P<0.05) and group D secrets more TGF-β than that in group C at the time points of 20, 36, 48 h (P<0.05); Group C and D expressed more Smad2, Smad3 and Smad4 than group A and B at the time point of 10 h after treatment. Meanwhile, cells in group D expressed more Smads than group C.

Conclusion: Cryoablation could promote TGF-β and its pathway, and the more close to the center of the ice ball, this effect is more apparent.