The Relationship Between The Expression Of RANKL/RANK/OPG And Invasive And Bone Metastases In Prostate Cancer

Objective:Prostate cancer is one of the most important tumors in the male urogenital tumors. Prostate cancer is the most prone to bone metastasis of malignant tumors, more than 80% of prostate cancer occur with bone metastases. Prostate cancer is a hormone-dependent tumors. Receptor activator of nuclear factor-κB (RANK), receptor activator of nuclear factor-KB ligand (RANKL) and osteoprotegerin (OPG) system was originally found in bone tissue, and are recently identified regulators of bone resorption and bone remodeling. It has been reported in recent years, RANK/RANKL/OPG has relationship with occurrence and development of a number of tumors including prostate cancers. It has also been reported RANKL/RANK signaling pathway has a chemotactic effect. The relationship between the expression of RANKL/RANK/OPG and invasive and bone metastases in prostate cancer and the relationship with hormone have not been established. To identify the relationship between them, we want to do some work.Methods:1 RANK, OPG, RANKL, AR expression were determined by immunohistochemistry in prostate cancer tissues from 70 patients. Expression of these proteins was correlated with clinicopathogic parameters of the prostate cancer.2 OPG, RANKL levels in serum and tissue were measured by ELISA in samples collected from 40 patients.3 Three kinds of human prostate cancer cell lines:PC3, DU145, LNCaP, using Western, RT-PCR method to detect the expression of RANK in them. 4 Transwell invasive tests was done to find sRANKL, OPG effects on invasiveness of prostate cancer cell.5 Transfection of antisense RNA to further clarify RANKL, OPG effects on cell invasiveness.Results:1 RANK, RANKL, OPG is not or weak expression in benign prostatic hyperplasia, but highly expressed in prostate cancer. In lymph node metastasis, high PSA, high expression of AR in prostate cancer, RANK, RANKL, OPG expression levels increased (P<0.05). The RANK, RANKL, OPG expression was significantly higher in bone metastases in prostate cancer (P<0.01)2 SRANKL, OPG expression in prostate cancer tissues were significantly higher than benign prostatic hyperplasia (P<0.05). In bone metastases, high PSA, high expression of AR prostate cancer, sRANKL, OPG expression levels in tissue increased (P<0.05). The expression of serum sRANKL has no relationship with age, Gleason score, tumor stage, PSA level, AR expression. Serum OPG lever expression levels increased in bone metastases, high PSA, high expression of AR prostate cancer, sRANKL, OPG expression levels increased (P<0.05). OPG serum levels and OPG tissue levels has a positive correlation. Regression equation:y= 0.9588x+0.4512 (R2= 0.7504, P<0.05). RANKL tissues levels and RANKL serum levels has no obvious correlation.3 Using western blot, RT-PCR detection of RANK expression in protein and mRNA in prostate cancer cell line PC3, DU145, LNCaP and normal prostate cells RWPE2: RANK expression in tumor cell lines were significantly higher than in normal prostate cells expression.4 Using transwell invasion assay observed RANKL, OPG on the invasiveness of prostate cancer cells:2.5μg/mIRANKL can significantly improve the PC-3, LnCap, DU145 cell invasion ability, had no effect on RWPE2 cell lines (P<0.05) 2.5μg/mlRANKL+10μg/mlOPG inhibited invasion enhanced by the RANKL (P <0.05). 5 RANK antisense RNA transfection and transwell invasion assay was used to clarify the RANKL on the invasiveness of prostate cancer cells:2.5μg/ml concentrations of RANKL environment can be seen in three prostate cancer cell lines, SiRNA-2 concentration from lOpg/ml can show effect of inhibition of invasion; 100pg/ml concentration can show a more significant effect of inhibition of invasion.Conclusion:1 Elevated expression of RANKL, RANK and OPG in prostate cancer tissues, correlated with tumor occurrence, advanced progression and metastasis. SRANKL, OPG levels in prostate cancer tissues and serum OPG levels closely related to cancer occurrence, invasion, and bone metastasis. There are positive correlation between the expression of OPG in cancer tissue and in serum. But the serum sRANKL levels and tissue RANKL level was no significant correlation.2 SRANKL can enhance prostate cancer cell invasiveness and bone metastasis which expression of RANK-positive. OPG as a soluble decoy receptor of RANKL, preventing binding RANKL and RANK can restrain prostate cancer cell aggressive and bone metastasis.