Department of Neurosurgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
Department of Radiotherapy and Oncology, Affiliated Kunshan Hospital of Jiangsu University, Kunshan, China.
Cell Death Dis. 2024 Jul 6;15(7):485. doi: 10.1038/s41419-024-06764-w.
The discovery of novel oncotargets for glioma is of immense significance. We here explored the expression patterns, biological functions, and underlying mechanisms associated with ORC6 (origin recognition complex 6) in glioma. Through the bioinformatics analyses, we found a significant increase in ORC6 expression within human glioma tissues, correlating with poorer overall survival, higher tumor grade, and wild-type isocitrate dehydrogenase status. Additionally, ORC6 overexpression is detected in glioma tissues obtained from locally-treated patients and across various primary/established glioma cells. Further bioinformatics scrutiny revealed that genes co-expressed with ORC6 are enriched in multiple signaling cascades linked to cancer. In primary and immortalized (A172) glioma cells, depleting ORC6 using specific shRNA or Cas9-sgRNA knockout (KO) significantly decreased cell viability and proliferation, disrupted cell cycle progression and mobility, and triggered apoptosis. Conversely, enhancing ORC6 expression via a lentiviral construct augmented malignant behaviors in human glioma cells. ORC6 emerged as a crucial regulator for the expression of key oncogenic genes, including Cyclin A2, Cyclin B2, and DNA topoisomerase II (TOP2A), within glioma cells. Silencing or KO of ORC6 reduced the mRNA and protein levels of these genes, while overexpression of ORC6 increased their expression in primary glioma cells. Bioinformatics analyses further identified RBPJ as a potential transcription factor of ORC6. RBPJ shRNA decreased ORC6 expression in primary glioma cells, while its overexpression increased it. Additionally, significantly enhanced binding between the RBPJ protein and the proposed ORC6 promoter region was detected in glioma tissues and cells. In vivo experiments demonstrated a significant reduction in the growth of patient-derived glioma xenografts in the mouse brain subsequent to ORC6 KO. ORC6 depletion, inhibited proliferation, decreased expression of Cyclin A2/B2/TOP2A, and increased apoptosis were detected within these ORC6 KO intracranial glioma xenografts. Altogether, RBPJ-driven ORC6 overexpression promotes glioma cell growth, underscoring its significance as a promising therapeutic target.
新型Glioma 癌基因的发现具有重要意义。我们在此探索了 ORC6（起始识别复合物 6）在 Glioma 中的表达模式、生物学功能和潜在机制。通过生物信息学分析，我们发现 ORC6 在人类Glioma 组织中的表达显著增加，与总生存期较差、肿瘤分级较高和野生型异柠檬酸脱氢酶状态相关。此外，在局部治疗的患者和各种原发性/已建立的Glioma 细胞中均检测到 ORC6 过表达。进一步的生物信息学研究表明，与 ORC6 共表达的基因富集在与癌症相关的多个信号级联中。在原代和永生化（A172）Glioma 细胞中，使用特异性 shRNA 或 Cas9-sgRNA 敲除（KO）耗尽 ORC6 显著降低了细胞活力和增殖，扰乱了细胞周期进程和迁移，并触发了细胞凋亡。相反，通过慢病毒构建体增强 ORC6 表达增强了人Glioma 细胞的恶性行为。ORC6 成为Glioma 细胞中关键致癌基因表达的重要调节剂，包括细胞周期蛋白 A2、细胞周期蛋白 B2 和 DNA 拓扑异构酶 II（TOP2A）。沉默或 KO ORC6 降低了这些基因的 mRNA 和蛋白水平，而 ORC6 的过表达增加了原代 Glioma 细胞中的表达。生物信息学分析进一步确定 RBPJ 为 ORC6 的潜在转录因子。RBPJ shRNA 降低了原代 Glioma 细胞中的 ORC6 表达，而其过表达增加了它。此外，在 Glioma 组织和细胞中检测到 RBPJ 蛋白与假定的 ORC6 启动子区域之间的结合显著增强。体内实验表明，在小鼠大脑中 ORC6 KO 后，患者来源的Glioma 异种移植瘤的生长显著减少。在这些 ORC6 KO 颅内 Glioma 异种移植瘤中检测到增殖抑制、Cyclin A2/B2/TOP2A 表达减少和细胞凋亡增加。总之，RBPJ 驱动的 ORC6 过表达促进了 Glioma 细胞的生长，强调了其作为有前途的治疗靶点的重要性。
