Expression Of Semenogelin I And Its Role In Migration And Invasion Of Renal Cell Carcinoma

Renal cell carcinoma(RCC), the most common type of renal cancer,has the highest mortality rate of the genitourinary cancers and accounts for about 3% of all cancer diagnosed each year. The diagnosis of RCC is confounded by the diversity of early clinical manifestations and the lack of cancer specific diagnostic techniques. About 60% of RCC are detected in patients unsuspected of harboring a genitourinary malignancy. The resistance of RCC to conventional cytotoxic and radiation therapies is also a cause of its high mortality rate. Although the development of targeted agents has improved clinical outcomes for patients with metastatic renal cell carcinoma, patients with metastatic RCC(p T4) still have a median survival of only 40 months and the 5 year survival rate is under 10%. In contrast, early stage(p T1-2) RCC can be cured by surgery. Hence, the early diagnosis of RCC, before metastases are present, has become even more critical.Semenogelin I(Sg I) is the major protein in human semen coagulum and playes an important role in semen liquefaction. In addition to expression in seminal vesicle, immunohistochemistry has been performed which demonstrates the expression of Sg I in trachea,pancreas, kidney, prostate and retina. Sg I has also been found to be expressed in human malignancies, including leukemia, small cell lung carcinoma, melanoma and prostate cancer, suggesting Sg1 may contribute to cancer carcinogenesis. Thus, we suppose that Sg1 may playes an important role in renal cell carcinomaTo test the hypothesis, we conduct a study to evaluate the Sg1 expression and its clinical significance in patients with RCC.PART I Seminal Plasma Protein in Renal Cell Carcinoma: Expression of Semenogelin I is a Predictor for Cancer Progression and PrognosisAims: The incidence of renal cell carcinoma(RCC) has been steadily rising each year. There are currently few recognized biomarkers for the diagnosis and prognosis of RCC. We investigated Semenogelin I(Sg I) expression and its clinical significance in patients with RCC.Methods: The expression level of Sg I and its protein were measured by q PCR and western blotting, respectively. Immunohistochemistry was used to investigate the protein expression of Sg I in RCC and normal renal tissue from 53 patients. The Kaplan-Meier method and log-rank test were used to evaluate the data.Results: By q RCR(p<0.01)and western blot,the level of Sg I expression inbenign tissues washigherthan that in RCC tissues. Expression of Sg I was observed in 30(57%) RCC, which was significantly lower than that observed in benign renal tissues from the same patients [Sg I-positive in 53(100%) cases(p<0.0001)] by immunohistochemistry. There was an inverse relation between Sg I expression and clinical stage(p T1-2 VS p T3-4, p<0.0001). Patients with Sg I-negative tumors had a significantly higher risk of recurrence(Kaplan–Meier and log-rank tests, p<0.0001)Conclusion: There was low Sg I expression in RCC. Sg I expression has potential value in predicting cancer progression and prognosis. These findings support the use of Sg I as a novel biomarker for RCC.PART II Semenogelin I Decreases Renal Cell Carcinoma Cells Migration and Invasion and Enhances Their Apotosis through Suppression of JNKObjective: The expression of semenogelin Iis closely related to the renal cell carcinoma progression and prognosis. The aims of this study were to verify the effect of semenogelin I on migration and invasion abilities of renal cell carcinoma cell lines 786-0 and ACHN, and to explore the underlying mechanisms.Materials and Methods: Renal cell carcinoma 786-0 and ACHN cells were stably transfected with Sg1 using lentivirus-mediated transfection, followed by MTT assay, cell cycleanalyses, transwell migratory assay, transwell invasion assay and flow cytometry for cellular apoptosis. Western blotting was used to analyisis the expression of JNK, p-JNK, c-fos and MMP9 proteins. JNK inhibitor sp600125 was uesd to confirm the correlationship between Sg1 and JNK signal transduction pathway.Results: Over-expression of Sg1 in renal cell carcinoma cells suppressed their migration and invasion in vitroand increased their cellular apoptosis, aslo induce cell cycle arrest at G2/M phase in 786-0 cell line.Western blotting showed that Sg1 increased JNK expression and inhibited p-JNK, c-fos and MMP9 expressions.Conclusions: These findings suggested that Sg1 plays an important role in renal cell carcinoma cells migration, invasion and cellular apoptosis by suppressing JNK and subsequent inactivation of c-fos, which provides a potential development of a new approach for the treatment of renal cell carcinoma.