The effect of high mobility group protein B1 on cryoimmunologic reaction in hormone-refractory prostate cancer: An experimental study in rats

Abstract

Objective To investigate the impact of high mobility group protein B1(HGMB1) on cryoimmunology response in hormone-refractory prostate cancer(HRPC).Methods Mouse models of HRPC were established by subcutaneous injection of RM-1 prostate cancer cells,and a total of 50 tumor-bearing mice were randomly divided into control group(n = 25) and cryoablation group(n = 25).Cryoablation was applied to the tumor lesion through cryosurgery needle with 1.7mm diameter by using Endocare Argon-Helium cryosurgery system(AHCS).The number and maturation changes of dendritic cell(DC) in tumor were assessed by flow cytometry and the levels of HMGB1 in tumor tissues were determined by Western blot technology one day before cryosurgery as well as one,7,14 and 21 days after cryosurgery separately.Results In cryoablation group,the levels of HMGB1 as well as the number and maturation of DC in tumor tissues reached their highest peaks in the 7th day after AHCS,and compared with the levels determined before treatment the differences were statistically significant(P 0.05).However,in control group no significant differences in the levels of HMGB1 as well as in the number and maturation of DC in tumor tissues existed between preoperative data and post operative ones(P 0.05).The levels of HMGB1 as well as the number and maturation changes of DC in tumor tissues determined at one,7 and 14 days after cryosurgery in cryoablation group were significantly higher than those in control group (P 0.05).Correlation analysis showed that the expression levels of HMGB1 had a parallel relationship with the number of DC(r = 0.883,P 0.05) as well as with the maturation changes of DC(r = 0.997,P 0.05) in the cryoablation group.Conclusion Cryoablation therapy can make the tumor cells release large amount of HMGB1 in association with tumor cell necrosis.And the released extracellular HMGB1 plays an important role in stimulating the body to produce the tumor-specific immune response after the cryoablation therapy.