Expression Of Claudin-4in Prostate Cancer And Preliminary Study Of Biological Function

Objective:To explore expression of Claudin-4protein in BPH, HGPIN, and prostate cancer, and the relationship of clinical staging, Gleason’s scores. Patients with prostate specific antigen (PSA) were followed up, we compare with clinical records of prostate-specific antigen (PSA) and Claudin-4-positive expression and Claudin-4-negative in prostate cancer, we explore the relationship between Claudin-4expression and PSA relapse. Furthermore, we go on study expression of Claudin-4in androgen-independent prostate cancer cell line PC-3, we investigate proliferation, migration and invasion abilities of PC-3cell after knocking down Claudin-4gene, it can be provide a new marker for the diagnosis, monitoring and followed-up of prostate cancer.Methods:Expression of Claudin-4protein were detected by using immunohistochemistry SP in42cases of BPH,37cases of HGPIN and68cases of prostate cancer tissue, combined with pathological Gleason scores, clinical stage with clinical followed-up data of patients with PSA, Kaplan-Meier survival analysis was used to study between relationship of PSA relapse and Claudin-4protein expression. Further, we explore expression of Claudin-4gene and protein in PC-3cell line by cell culture, qPCR, Western blot; We further carry on to transfect PC-3cells with targeted RNA interference (Claudin-4-siRNA) plasmid, and application of PCR and western blot technique to detect the interference effect by MTT, Transwell test and cell cycle analysis. Last, these results were analyzed statistically.Results:(1) Expression of Claudin-4protein was a small amount expressing in benign prostate hyperplastic(BPH) tissue, it was express moderate quantity in HGPIN, and express large number of Claudin-4in prostate cancer(PCa), Claudin-4protein expression positive rates in benign prostate hyperplastic tissue, HGPIN and prostate cancer were14.29%(6/42),35.14%(13/37),61.76%(42/68), these results showed they were statistically significantly different in benign prostatic hypeiplasia, prostate high-grade neoplasia and prostate cancer; Expression of Claudin-4protein Positive rate was different with Gleason’s score<7score,=7score,>7score in prostate cancer, they were40.74%(11/27),52.63%(10/19),86.36%(19/22), it are significant differences among the three groups (P<0.05). howover, they are not significant differences between Gleason’s score≤6and=7in prostate cancer; Claudin-4protein expression rates in TNM staging Ⅰ, Ⅱ and Ⅲ, Ⅳ were48.72%and79.31%, they was different between them, it was statistically significant (P<0.05); Claudin-4 expression is closely related with clinical stage, Gleason’s score in prostate cancer tissue;(2)68patients with prostate cancer were followed-up PSA vulve with an average of36months, Claudin-4protein expression and data of PSA vulve were analysised and found that PSA relapse rate were45.45%(10/22) and78.26%(36/46) by the Kaplan-Meier survival analysis, it was significant difference between them (P <0.05);(3) PC-3cells were used for RT-PCR and Western blot test, we found that Claudin-4gene and protein expression were increased, Targeted interference of Claudin-4plasmid was stable builded, after Claudin-4-siRNA transfected PC-3cells was compared with the normal cell group and the empty plasmid group, Claudin-4-siRNA transfected cells proliferation, migration and invasion ability were reduced, and cell cycle was arrested, there was significant difference between them.Conclusion:Expression of Claudin-4protein in prostate cancer is closely related with Gleason grade, clinical stage and PSA relapse, suggesting the Claudin-4gene may be play an important role in the evolution and progression of prostate cancer, it may be a prognostic indicator in prostate cancer. Rising Claudin-4expression in prostate cancer is a risk factor for prostate cancer progression and prognosis of patients with PSA recurrence, these results suggest Claudin-4increased expression may be a poor prognosis markers in prostate cancer. Specifically Claudin-4-siRNA can inhibit the Claudin-4expression in PC-3cells, PC-3cells was decreased in proliferation, migration and invasion ability, its cell cycle was arrested, These results suggest Claudin-4was related to malignant behavior of prostate cancer, it can be a predictor of progress of prostate cancer.