Experimental Study on Selective Cyclooxygenase-2 Inhibitor Combined with Radiotherapy for Human Prostate Carcinoma Xenografts in Nude Mice

Objective To investigate the anti-tumor and radiation-enhancement effects and observe a coordinate repression of celecoxib, a selected cyclooxygenase -2 inhibitor in prostate carcinoma. Methods An animal model of human prostate carcinoma in BALC/C male nude mice was establised by injecting suspension of PC-3 cells and the mice were randomly divided into 4 groups which were interfered with celecoxib, radiation, and both celecoxib and radiation respectively, with 6 rats in each group. The effect of treatment was assessed by tumor growth delay (TGD)and radiosensitization enhancement effector (EF); the tumor tissues were collected and assessed for the detection of cyclooxygense-2 mRNA and prostaglandin E2 by RT-PCR and ELISA, and histopathological changes of transplanted mouse’s important organs were observed. Results The time that the longest diameters of all tumors growing from 8.0mm to 12.0mm for the control group and the celecoxib group was(6.18±0.72)d and(7.87±0.76)d, respectively ,while the time for the radiation group and celecoxib+radiation group was (9.16±0.89)d and (12.62±1.28)d respectively. The growth of tumors was significantly different among these groups (P0. 05)and EF was 1.59; there was obvious differences in prostaglandin E2 levels between the control group and other groups(P0.05),while there was not obvious differences in prostaglandin E2 levels between the radiation group and celecoxib+radiation group(P0.05). Significant correlations were found between the growth delayed by celecoxib and the drop of prostaglandin E2 levels (r=0.807); Analysis of variance showed that there was no significant difference in cyclooxygense-2 mRNA among these four groups (P 0.05). No significant toxic pathological changes of transplanted mouse’s important organs were observed. Conclusion Our results suggest a coordinative repression between celecoxib and radiation in inhibiting human prostate carcinoma xenografts by the anti-tumor and radiation-enhancement, which is safe and effective in some extent and may contribute to enlighten the future study and clinical therapy of prostate carcinoma.