Clinical Laboratory of The Second People's Hospital of Hunan Province, Changsha, Hunan 410007, P.R. China.
Clinical Medical College of Hunan University of Chinese Medicine, Changsha, Hunan 410007, P.R. China.
Oncol Rep. 2019 Apr;41(4):2329-2336. doi: 10.3892/or.2019.6987. Epub 2019 Jan 30.
Sperm‑associated antigen 9 (SPAG9) is a biomarker and potential therapeutic target for several cancers; however, its involvement in liver cancer progression is not clear. The aim of the present study was to determine whether SPAG9 regulates proliferation of liver cancer. Immunohistochemistry and cell immunofluorescence were used to confirm the expression and the localization of SPAG9 in human liver cancer tissues and the liver cancer‑derived HepG2 cells. A small interfering RNA (siRNA) designed to target SPAG9 was transiently transfected into HepG2 cells using Lipofectamine™ 2000, and proliferation, apoptosis and cell cycle progression were analyzed using CCK‑8 assay and flow cytometry; western blotting was used to detect the expression of SPAG9, JNK, p38, MKK3 and MKK6, and co‑immunoprecipitation was used to assess the interaction between SPAG9 and JNK. SPAG9 was overexpressed in 16 out of 20 (80%) patients with liver cancer. The protein was localized in both the cytoplasm and nucleus of liver cancer cells obtained from patients and in HepG2 cells. Depletion of SPAG9 inhibited the proliferation of HepG2 cells, promoted apoptosis and arrested the cell cycle at the S phase. Moreover, cells deficient in SPAG9 had decreased expression of JNK, p38 and MKK3 compared to HepG2 cells not treated with an siRNA targeting SPAG9. In the present study, SPAG9 was revealed to regulate cell proliferation, apoptosis and cell cycle progression in liver cancer cells through the SPAG9/MKK3/p38 axis. This axis is a novel therapeutic target for liver cancer.
精子相关抗原 9（SPAG9）是几种癌症的生物标志物和潜在治疗靶点；然而，其在肝癌进展中的作用尚不清楚。本研究旨在确定 SPAG9 是否调节肝癌的增殖。免疫组织化学和细胞免疫荧光用于确认 SPAG9 在人肝癌组织和肝癌衍生的 HepG2 细胞中的表达和定位。使用 Lipofectamine™2000 将针对 SPAG9 的小干扰 RNA（siRNA）瞬时转染到 HepG2 细胞中，使用 CCK-8 测定法和流式细胞术分析增殖、凋亡和细胞周期进展；使用 Western blot 检测 SPAG9、JNK、p38、MKK3 和 MKK6 的表达，使用共免疫沉淀评估 SPAG9 和 JNK 之间的相互作用。在 20 名肝癌患者中有 16 名（80%）SPAG9 过表达。该蛋白定位于患者来源的肝癌细胞的细胞质和细胞核以及 HepG2 细胞中。SPAG9 的缺失抑制了 HepG2 细胞的增殖，促进了细胞凋亡并使细胞周期停滞在 S 期。此外，与未用靶向 SPAG9 的 siRNA 处理的 HepG2 细胞相比，缺乏 SPAG9 的细胞中 JNK、p38 和 MKK3 的表达降低。在本研究中，SPAG9 通过 SPAG9/MKK3/p38 轴调节肝癌细胞中的细胞增殖、凋亡和细胞周期进程。该轴是肝癌的一种新的治疗靶点。
