Clinical implication and expression characteristics of polycomb repressive complex 1 in glioma

Objective To study the expression characteristics of polycomb repressive complex 1 (PRC1) gene in glioma and its influence on the survival of patients, as well as the influence on glioma cells after regulating its expression in vitro, and to evaluate the clinical significance of PRC1 in glioma. Methods Through TCGA database glioma database mining PRC1 mRNA level in glioblastoma tumor tissue, the level of the differences between different level of the WHO, the types of cases, 56 cases of glioma tumor samples of immunohistochemical staining to evaluate PRC1 expression characteristics and the relationship between Ki67, 6 glioma cell line by comparing protein imprinting experiments with astrocytes in PRC1 protein expression level difference, Transcriptome data of patients with high expression of PRC1 and patients with low expression of PRC1 in TCGA database were analyzed to study the molecular signaling pathways that may be regulated by PRC1, and to explore the clinical significance of PRC1 in glioma. Results The higher the WHO level was, the higher PRC1 mRNA (PRC1 mRNA level: Grade Ⅲ vs. Grade Ⅱ: t=9.665, P<0.05; Grade Ⅳ vs. Grade Ⅲ: t=11.200, P<0.05; Grade Ⅳ vs. Grade Ⅱ: t=24.980, P<0.05; PRC1 IHC staining intensity level: Grade Ⅳ vs. Grade Ⅱ: t=8.120, P<0.05; Grade Ⅳ vs. Grade Ⅲ: t=5.957, P<0.05), and protein levels were, and the levels in glioblastoma were significantly higher than those in oligodendroglioma, oligodendroglioma, and astrocytoma (Oligodendroglioma vs. glioblastoma: t=16.110; oligodendroglioma vs. glioblastoma: t=15.460; astrocytoma vs. glioblastoma: t=13.290, all P<0.05; PRC1 IHC staining intensity level: F=20.540, P<0.05). Compared with normal brain tissue, PRC1 mRNA level in glioblastoma was significantly increased (t=6.432, P<0.05). The protein expression level of PRC1 in glioblastoma cell lines was significantly higher than that in normal astrocytes (U87MG vs. HA: t=3.797, U118MG vs. HA: t=5.008, U251 vs. HA: t=4.435, T98G vs. HA: t=5.867, A172 vs. HA: t=4.809, LN229 vs. HA: t=6.242, all P<0.05). The median survival time of patients in the PRC1 high-expression group was significantly lower than that in the PRC1 low-expression group, which was 13.3 months and 40.45 months, respectively (χ2=23.990, P<0.05). PRC1 was involved in the regulation of cell cycle and p53 signaling pathway, and there was a significantly positive correlation between PRC1 and proliferating cell nuclear antigen (Ki-67) (P<0.05). Conclusion PRC1 is abnormally highly expressed in glioma, and the tumor proliferation with high expression of PRC1 is significantly enhanced with higher malignant degree, indicating a poor clinical prognosis. PRC1 may be a new therapeutic target for glioma. Key words: Polycomb repressive complex 1; Glioma; Prognosis