Study Of Expression Of Enhancer Of Zeste Homolog 2 And Its Value In Prostate Cancer

Objective:To detect the expression levels of EZH2 in prostate cancer cell lines (PC-3 and LNCAP) and in the clinical specimens of prostatic hyperplasia,then analyze the relationship between EZH2 and clinical pathological features of the prostate cancer. To detect the expression levels of EZH2 in the PC3 cell before and after radiotherapy. And then discuss the function and mechanism of EZH2 gene in prostate cancer, in order to look for a new bio-marker of diagnosis and theraputic target of prostate cancer.Methods:1. The expression level of EZH2 protein were detected by Western-Blot in prostate cancer PC-3 cell line, LNCAP cell line and normal prostate epithelial RWPE cell line; 2. Clinical specimens of prostate cancer(n=35) and benign prostatic hyperplasia(n=8) were selected, the expression levels of EZH2 mRNA and protein of these specimens were detected by Reverse Transcription PCR and Western-Blot. And then analyze the relationship between the expression levels of EZH2 and the pathological features of prostate cancer; 3. The expression levels of EZH2 in PC-3 cell line were detected by Western-Blot before and after radiotherapy.Results1. The expression levels of EZH2 protein in PC-3 cell line and LNCAP cell line were higher than the RWPE cell line[4.485(3.181,4.774), 1.235(1.138,1.302) vs 0.588(0.394,0.649)], the expression levels of EZH2 protein had a statistically significant difference in different prostate cell lines (P<0.01).2. The expression levels of EZH2 mRNA in prostate cancer were higher than benign prostatic hyperplasia, and there was a statistically significant difference between the two groups(1.69±0.19 vs 0.79±0.10,P﹤0.01); the expression levels of EZH2 protein in prostate cancer were higher than benign prostatic hyperplasia, and the difference was significant between the two groups (1.67±0.20 vs 0.62±0.10,P﹤0.05).3. The expression levels of EZH2 protein in stage T3-T4 were higher than in stage T1-T2(T₃-T₄:2.514±0.2809 vs T₁-T₂:0.9322±0.07062), there was a statistically significant difference between the two groups(P<0.01); the expression levels of EZH2 protein in prostate cancer with lymph node metastasis were higher than that in prostate cancer without lymph node metastasis (N₁:3.293±0.3566 vs N₀:1.177±0.09800), there was a statistically significant difference between the two groups (P<0.01); the expression levels of EZH2 protein in prostate cancer with distant metastasis were higher than that in prostate cancer without distant metastasis(M₁:3.808±0.4843 vs M₀:1.342±0.1261), and there was a statistically significant difference between the two groups(P<0.01); the expression levels of EZH2 protein in Androgen-Independent prostate cancer were higher than that in Androgen-Dependent prostate cancer(AIPC:2.535±0.5326 vs ADPC:1.357±0.1386), there was a statistically significant difference between the two groups(P﹤0.05). The expression of EZH2 protein was no statistically significant in the age, PSA and Gleason score(P>0.05).4. The expression levels of EZH2 protein in PC-3 cell line were low after radiotherapy, the expression levels of EZH2 protein in PC-3 cell line were high before radiotherapy, there was a statistically significant difference between the irradiation group and the control group[0.8681(0.667,1.012) vs 3.181(2.793,4.485),P﹤0.05], there is no statistically significant difference in different hour points of PC-3 cells after radiotherapy.Conclusions1. The expression levels of EZH2 protein in both PC-3 cell line and LNCAP cell line are higher than RWPE cell line, which suggests that EZH2 may play an important role in prostate cancer.2. The expression levels of EZH2 mRNA and protein are higher in prostate cancer specimens than in benign prostatic hyperplasia. In additoion, there is a positive correlation between the expression levels of EZH2 and the clinical stage of prostate cancer. Thus, EZH2 may become a new marker for the diagnosis of prostate cancer.3. The expression levels of EZH2 are higher in AIPC than in ADPC, which suggests that EZH2 may take part in the transformation from ADPC to AIPC.4. The expression levels of EZH2 protein in PC-3 cell line after performing ionizing radiation are lower than before, which suggests that ionizing radiation can significantly reduce the expression of EZH2 in the PC-3 cell line.