Department of Thoracic Surgery, The First Hospital of China Medical University, Shenyang, Liaoning, China.
Environ Toxicol. 2024 Dec;39(12):5321-5333. doi: 10.1002/tox.24407. Epub 2024 Aug 31.
RING finger protein 135 (RNF135) is identified as a regulator in certain cancer types. However, its role and molecular mechanisms in lung adenocarcinoma (LUAD) are still unclear. Herein, we investigated the level of RNF135 in tumor tissues of LUAD patients using the UALCAN database and confirmed the data by real-time PCR and western blot analysis. The effects of RNF135 on stemness maintenance and migration/invasion capability of LUAD cells were investigated by sphere formation, flow cytometry, wound healing, and transwell assay. Limiting dilution xenograft assay and intracardiac injection of LUAD cells were applied to assess the implications of RNF135 in tumorigenesis and brain metastasis. Our results revealed that RNF135 was upregulated in tumor tissues of LUAD patients and was positively correlated with poor prognosis. Knockdown of RNF135 suppressed cancer stem cells (CSCs)-like properties, and migration/invasion capability of A549 and NCI-H1975 cells. Conversely, overexpression of RNF135 augmented CSCs-like traits and migration/invasion ability of LUAD cells. Limiting dilution xenograft assay demonstrated that RNF135 was required for the self-renewal of CSCs to initiate LUAD development. Overexpression of RNF135 in A549 cells increased their ability to metastasize to the brain in vivo. Mechanistically, the transcriptional activation of RNF135 by LSD1 involved H3K9me2 demethylation at the promoter region of RNF135. Reexpression of RNF135 in LSD1-silenced A549 cells was able to reverse LSD1-mediated stemness maintenance and migration/invasion capability. Overall, our results implied that targeting of LSD1/RNF135 axis might be a feasible method to suppress tumorigenesis and brain metastasis of LUAD patients.
环指蛋白 135（RNF135）被鉴定为某些癌症类型的调节剂。然而，其在肺腺癌（LUAD）中的作用和分子机制尚不清楚。在此，我们使用 UALCAN 数据库研究了 LUAD 患者肿瘤组织中 RNF135 的水平，并通过实时 PCR 和 Western blot 分析验证了数据。通过球体形成、流式细胞术、划痕愈合和 Transwell 测定研究了 RNF135 对 LUAD 细胞干性维持和迁移/侵袭能力的影响。限制稀释异种移植测定和 LUAD 细胞的心内注射用于评估 RNF135 在肿瘤发生和脑转移中的意义。我们的结果表明，RNF135 在 LUAD 患者的肿瘤组织中上调，并与不良预后呈正相关。RNF135 的敲低抑制了 A549 和 NCI-H1975 细胞的癌症干细胞（CSC）样特性和迁移/侵袭能力。相反，RNF135 的过表达增强了 LUAD 细胞的 CSC 样特征和迁移/侵袭能力。限制稀释异种移植测定表明，RNF135 是启动 LUAD 发展的 CSCs 自我更新所必需的。在 A549 细胞中过表达 RNF135 增加了它们在体内向大脑转移的能力。在机制上，LSD1 通过 LSD1 参与 RNF135 启动子区域的 H3K9me2 去甲基化来激活 RNF135 的转录。在 LSD1 沉默的 A549 细胞中重新表达 RNF135 能够逆转 LSD1 介导的干性维持和迁移/侵袭能力。总的来说，我们的结果表明，靶向 LSD1/RNF135 轴可能是抑制 LUAD 患者肿瘤发生和脑转移的可行方法。
