Expression of EZH2 and P53 and their correlation in ovarian cancer tissues

Abstract

Previous researches have demonstrated that EZH2 expression is increased in many solid tumors and is closely related to the worse progression, transcriptional silence, distal metastasis, and differential inhibition of tumors. P53 can regulate many cells signaling pathways and play an important role in cell cycle, cell apoptosis, and cell senescence. However, there are few reports on the expression of EZH2 and p53 in ovarian cancer and their correlation with the ovarian cancer. The purpose is to elucidate the expression of EZH2 and p53 in ovarian cancer and to study the relationship of EZH2 and p53 with the clinical parameters of ovarian cancer. In this study, both mRNA and protein level of EZH2 in ovarian cancer group was significantly higher than that in borderline, benign, and normal group; while the mRNA and protein level of p53 was significantly lower than that in borderline, benign, and normal group. The expression of EZH2 protein was mainly located in the cytoplasm and nucleus, while mutated p53 protein was mainly located in the nucleus. Furthermore, the expression of EZH2 is closely related to the FIGO stage and histological grade of ovarian cancer. EZH2 and P53 are closely related to the occurrence of ovarian cancer. We speculate that EZH2 may promote the development of ovarian cancer by inhibiting the expression of p53, suggesting that p53 may be the target gene of EZH2.

Keywords: EZH2; clinical stages; immunohistochemical; ovarian cancer; p53.

Figure 1

Detection of EZH2 and p53 mRNA expression levels in ovarian tissues. A. Relative expression level of EZH2 mRNA in normal, benign, borderline, and malignant ovarian tissues was detected by RT-qPCR. The level of EZH2 mRNA in malignant group was significantly increased compared with other three groups respectively. B. Compared with other three groups respectively, RT-qPCR revealed that the relative expression level of p53 mRNA in malignant ovarian tissues was dramatically decreased in malignant ovarian tissues.

Figure 2

Detection of EZH2 and p53 protein expression levels in ovarian tissues. A. Western blot was performed to measure EZH2 and p53 protein expression levels in benign, normal, borderline, and malignant group. GAPDH was used as an internal control. B. Compared with other three groups respectively, western blot analysis indicated that the relative expression level of EZH2 protein was significantly increased in malignant ovarian tissues. C. The relative expression level of p53 protein was dramatically increased in malignant group compared with normal and benign group respectively. There was no significant difference between ovarian cancer group and borderline group.

Figure 3

Immunohistochemical expression of EZH2 and p53 in ovarian tissues. A. The expression of EZH2 protein was predominantly expressed in the cytoplasm and nucleus. Ovarian cancer group tended to express EZH2 protein in the nucleus with those containing dark brown granules, while benign group and normal group tended to express in the cytoplasm with or without only small stain intensity. p53 protein was mainly located in the nucleus. Images were taken at ×100 magnification and a zoomed-in section was shown below each image. B. The positive rate of EZH2 protein in ovarian cancer group was significantly higher than that in benign, normal, and borderline group. C. The positive rate of p53 was significantly higher in malignant group compared with other three groups.

Figure 4

Correlation between the mRNA and protein expression levels of EZH2 and p53. The mRNA and protein levels of EHZ2 and p53 were expressed inversely in ovarian tissues (A, B).