Effect of Iodine 125 seeds short time low dose rate irradiation on perineural invasion in pancreatic cancer Capan-2 cells / 中华胰腺病杂志

ABSTRACT

Objective To investigate the effect of Iodine 125 seeds short time low dose rate irradiation on perineural invasion (PNI) in pancreatic cancer Capan-2 cells,and explore its molecular mechanism.Methods The co-culture model was established by co-culturing the dorsal root ganglion (DRG) of SD rat and Capzn-2 cells line,while Capan-2 culture model and DRG culture model was also established.Iodine 125 seeds short time low dose rate irradiation tablet was used for the 3 models,and the model without irradiation was used as control.Cancer cell and DRG growth was observed under inverted microscopy,surface of neurite and cell colony growth was determined by image analysis software.The concentration of nerve growth factor (NGF),transforming growth factor-α (TGF-α) in cell culture supernatant and matrigel solution was tested by ELISA,and the expression of neurotrophin-3 (NT-3) mRNA was detected by semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR).Results In the co-culture model,neurite of DRG showed a direction to cancer cells and had a concentrated growth towards cancer cells.And Capan-2 cells formed more colonies towards neurite.However,in irradiation groups,the symbiotic phenomenon was inhibited to some degree.Increased surface of neurite in co-culture model at 5th day was 290.15 ± 12.08,which was significantly higher than that in DRG group (124.83 ± 6.96,P ＜ 0.01),but the surface of neurite was decreased to 201.53 ± 12.20 after irradiation (P ＜0.01).Increased surface of Capan-2 cell was 300.47 ± 12.99,which was significantly higher than that in Capan-2 group (199.30 ± 8.60,P ＜ 0.01),but the surface of Capan-2 was decreased to 202.35 ± 7.97 after irradiation (P ＜ 0.01).NT-3 mRNA was seldom or not expressed in supernatant of co-culture model,but it was strongly expressed (0.68 ± 0.04) after irradiation (P ＜ 0.05).The concentration of NGF and TGF-α in supernatant of co-culture model were (27.56 ± 13.73),(40.86 ± 20.73) ng/ml,after irradiation they were increased to (94.98 ± 33.80),(157.54 ± 83.76) ng,/ml,and the difference between the two groups was statistically significant (P＜0.05 or ＜0.01).The concentration of NGF and TGF-α in matrigel lysate of co-culture model were (60.42 ± 33.03),(64.39 ± 21.52)ng/ml,after irradiation they were increased to (132.52 ±53.01),(138.38 ±83.58)ng/ml,and the difference of NGF concentration between the two groups was statistically significant (P ＜ 0.05).Conclusions Iodine-125 seeds short-time low-dose rate irradiation could inhibit interactions between nerve and Capan-2 cells,and the mechanism may be related to up-regulation of cancer cells perineural invasion promoter NGF,TGF-α and NT-3.