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Enhancer of zeste homolog 2 (EZH2), the critical component of polycomb group protein family, has been demonstrated to be overexpressed in various types of human cancer, including hepatocellular carcinoma, breast, bladder and lung cancer. The mechanism of how EZH2 promotes oncogenesis has also been well studied. However, little is known about the role of EZH2 in colorectal cancer (CRC). The main purpose of the present study was to analyze the association between EZH2 expression and the clinicopathological features of CRC. Therefore, the mRNA and protein expression levels were analyzed in tumor tissues and adjacent non‑cancerous tissues by reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) and western blot analysis. The expression of EZH2 was demonstrated to be significantly increased in tumor tissues compared with adjacent noncancerous tissues, according to the results of western blot analysis and RT‑qPCR in the majority of cases. Patients with low EZH2 expression had a longer overall survival rate compared with those with high EZH2 expression. An analysis of the association between clinicopathological features and EZH2 expression indicated that high EZH2 expression was significantly associated with tumor stage, tumor size, histological differentiation and lymph node metastasis. Multivariate analysis demonstrated that high EZH2 expression was an independent predictor of overall survival. In conclusion, to the best of our knowledge, the data presented in the present study is the first to indicate that EZH2 is upregulated in CRC and may serve as a predictor of poor outcome for patients with CRC. [ABSTRACT FROM AUTHOR]

Objective: To investigate the effect and its possible mechanism of interleukin-17 (IL-17) on invasion and metastasis of human colon cancer cells., Methods: IL-17 was added into the culture media of human colon cancer cells SW480 and LOVO. Cells were divided into 4 groups: SW480 control group (SW480 cells), LOVO control group (LOVO cells), SW480 experiment group (50 μg/L IL-17+SW480 cells), and LOVO experiment group (50 μg/L IL-17+LOVO cells). Cell growth was measured by CCK-8 assay. The proliferation rate(%)=[(Aexperiment group-Ablank)/(Acontrol group-Ablank)]×100%). The ability of cell invasion and migration was measured by transwell assay. Real time-PCR was used to detect mRNA expression of VEGF and MMP-9. Western blot was performed to detect protein expression of STAT3, p-STAT3, VEGF and MMP-9. Enzyme-linked immunosorbent assay (ELISA) was applied to measure the protein content of VEGF and MMP-9 in the supernatant., Results: After cultivation for 24, 48 and 72 hours, CCK-8 assay revealed that the proliferation rate of SW480 was 1.18%±0.07%, 1.42%±0.09%, and 1.62%±0.08%; the proliferation rate of LOVO was 1.13%±0.02%, 1.32%±0.05% and 1.73%±0.02% in experiment group. Transwell experiments showed that after cultivation with IL-17 for 24 hours, number of invasion cell in experimental groups (SW480: 34.00±0.45, LOVO: 41.60±0.51) was higher as compared to corresponding control groups (SW480: 4.53±0.14; LOVO: 3.67±0.33) with significant differences (SW480: t=-76.026, P=0.001; LOVO: t=-81.580, P=0.005). The number of migration cell in experimental groups (SW480: 36.40±0.51, LOVO: 46.40±0.68) was higher as compared to corresponding control groups (SW480: 7.83±0.69; LOVO: 6.67±0.48) with significant differences (SW480: t=-51.542, P=0.003; LOVO: t=-49.265, P=0.005). Real-time PCR results revealed that after cultivation with IL-17 for 24 hours, VEGF and MMP-9 mRNA relative expression levels in experimental groups (SW480: VEGF:1.53±0.12, MMP-9: 2.44±0.23; LOVO: VEGF: 2.96±0.35, MMP-9: 3.38±0.55) were higher than those in control groups (both 1) with significant differences (VEGF: t=3.799, P=0.043; MMP-9: t=5.254, P=0.039). Western blot illustrated that after cultivation with IL-17 for 24 hours, STAT3, p-STAT3, VEGF and MMP-9 proteins relative expression levels in experimental groups were significantly higher that those in control groups (SW480:STAT3: t=3.233, P=0.023; p-STAT3: t=3.954, P=0.032; VEGF: t=3.201, P=0.025; MMP-9: t=3.154, P=0.029; LOVO: STAT3: t=3.788, P=0.012; p-STAT3: t=2.662, P=0.040; VEGF: t=4.118, P=0.035; MMP-9: t=4.268, P=0.030). ELISA indicated that content of VEGF and MMP-9 in the supernatant of experimental groups (SW480: VEGF 5 491.41±63.22, MMP-9: 21.43±1.35. LOVO: VEGF: 8 631.46±129.59, MMP-9: 178.32±3.20) were higher than those in control groups (SW480: VEGF:4 456.32±87.56, MMP-9:18.57±2.44. LOVO: VEGF: 8 122.38±108.66, MMP-9: 163.22±6.89) with significant differences (SW480: VEGF: t=6.993, P=0.037; MMP-9: t=5.587, P=0.040. LOVO: VEGF: t=7.013, P=0.044; MMP-9: t=6.762, P=0.043)., Conclusion: IL-17 may be able to activate STAT3 signal transduction pathway in vitro through up-regulation of VEGF and MMP-9 expression, thereby enhancing the invasion and migration of colon cancer SW480 and LOVO cells.