Expression And Significance Of Tumor-Associated Trypsinogens In Prostate Cancer

Prostate cancer is one of the common malignancy in genitourinary system of man. The molecular modulation of prostate cancer is still unknown.Trypsinogens are pancreatic serine proteinases and expressed in several cancers as tumor-associated trypsinogens (TAT) in rescent years'research. Being highly potent proteinase, TAT way promote aggressiveness and invasion in PCa by activating some proteinases, such as pro-uPA and pro-MMPS, and promote angiogenesis and tumor invasion.Trypsinogens are pancreatic serine proteinases and expressed in several cancers as tumor-associated trypsinogens(TAT). TAT was first detected at high concentrations in cyst fluid of ovarian tumors. Extrapancreatic expression of TAT has also been detected in the lung, gastric, and colorectal cancer as well as in related cancer cell lines. In ovarian cancer, TAT expression has been shown to be related to the malignant potential of the tumors. Accumulating evidence indicates that trypsin may be involved in tissue remodeling and tumor invasion. Trypsin hydrolyzes peptide bonds at the carboxyl side of arginine and lysine residues, and it efficiently activates various serine and matrix metalloproteinases. Human trypsin is more potent than plasmin and other serine proteninases in activating the latent forms of many MMPS. Recently, trypsin was shown to induce cell signaling through PAR-2 in LNCap cells leading to activation of RhoA and other members of the Rho family of small GTPases, which are in volvoed in cytoskeletal reorganization. Fluorescence microscopy studies showed that LNCaP cells treated with trypsin developed an increased number of filopodia, stress fibers, and focal adhesions relative to untreated cells. These cytoskeletal changes are essential compoents for cancer cell growth and metastasis since invasion through vessel wall, and cell division requires extensive cytoskeletal reorganizations. Trypsin may affect the behavior of PCa also by degrading insulin-like grouth factor–1 (IGF-1)has been shown to have mitogenic and anti-apoptopic effects on prostate epithelial cells in vitro. Increased circulating IGF-1 levels have also been shown to be associated with increased risk of PCa. Serveral serine and matrix metalloproteinases (MMPs) are expressed in the prostatic epithelium. These include prostate-specific antigen (PSA), human kallikrein-2(hk2), urokinase and tissue-type plasminogen activator (upAand tPA). Based on other findings of TAT expression in benigh prostatic epithelium and the finding that trypsin activates pro-upA, pro-MMP-2, pro-MMP-7, pro-MMP-9, which play central roles in angiogenesis, tumor invasion and metastases, we decided to study the expression of TAT in prostate cancer(PCa).Expression of TAT in PCa and BPH was studied by immunohistochemitry, in situ hybridization and RT-PCR , This study is to investigate the changes of TAT in PCa and BPH to approach the effect of TAT on the development of PCa. Serum TATI was measured with immunoradio metric assay (IRMA) in 16 patients with PCa and 16 patieuts with BPH.The results of research showed that expression of TAT in epithelial cells of the malignant prostate gland was demonstrated by IHC. Strong immunostaining was generated with monoclonal anti-TAT mAbs in PCa and was in creased with higher Gleason's grade. A weak immunostaining for TAT was observed in the stromal compartment in BPH tissue section .Fluorescein-labeled 512 bases long antisense and seuse probes were used to detect TAT transcripts in adjactent sections from benign and malignant prostatic tissue. A heterogenous distribution of TATmRNA was found in tumor areas. The hybridization signals were increased with higher Gleason's grade.To develop the immunoradiometric assay (IRMA)for TATI and trying to apply it in cancer diagnosis, the serum TATI levels of 16 PCa patients and 16 BPH individuals were detected and compared with each other. The recoveries of detection of serum TATI were (42.8±8.3μg/L)and (16.2±2.7μg/L), respectively in PCa patients and in BPH patients by IRMA. The TATI value in PCa patients were increased with Gleason's grade and were decreased after the medical castration of prostate cancer patients with Luteinizing hormone-releasing hommone analog, (LHRH-A) and androgen ablation drug .We assay the changes of TATI Value of medical treatmeut.This study shows :1.Expression of TAT in epithelial cells of the benign and malignant prostate gland was demonstrated by IHC and ISH. Strong immunostaining was generated with monoclonal anti-TAT in PCa. The significance level was set to a p-value of <0.05 between PCa and BPH.2.Immunostaining intensity and transcripts hybridization signals of TAT were increased with higher Gleason's grade.3.The quantity of TATmRNA RT-PCR products amplified from the tissue of PCa were more than that from the tissue of BPH, P<0.05.4.The recoveries of detection of serum TATI were (42.8±8.3μg/L) and (16.2±2.7μg/L), respectively in PCa patients and in BPH patieuts by IRMA. The TATI value in PCa group was most than anther group significantly (P<0.05)though TUNEL assay.5.The serum TAT value in PCa patients were decreased after treatment of the medical castration of prostate cancer patients with LHRH-A and androgen ablation drug (P<0.05).Through the integrated analysis,conclusion could be drawn:1.The results of the present study show that TAT is stronly expressed in prostatic tumors and metastases and that expression is preserved and slightly elevated with increasing tumor aggressiveness the difference is significant (p<0.05,respectively)2.This study show that the expression of TAT in PCa tissue was significantly correlated with the aggressive and metastatic biologic behavior of PCa3 .The studies on the role of TAT in invasion PCa and on the mechanisims may have potential value for the diagnosis and prediction of PCA prognosis .This study also provides a substantial theoretical foundation to seek a new and offective therapy of PCa.4.Being a higly potent proteinase, trypsin may promote aggressiveness and invasion in PCA by both activating and degrading of other proteinases .Futher studies on the role of TAT invasive PCa and on the mechanisms involved in the regulation of TAT expression are warranted.5.Due to the decreasing of TATI after medical treatment , TATI could be used as an important index to judge the effects of medical treatment and the prediction of prognosis with PCa.