Cancer Molecular Targeted Herbal Research Laboratory, College of Korean Medicine, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu, Seoul 02447.
Int J Biol Sci. 2024 Jun 17;20(9):3442-3460. doi: 10.7150/ijbs.93462. eCollection 2024.
In this study, we explored the oncogenic mechanism of cleavage and polyadenylation-specific factor 6 (CPSF6) in hepatocellular carcinoma (HCC). CPSF6 was overexpressed in HCC tissues with poor survival rates compared to normal tissues. Hence, CPSF6 depletion suppressed cell viability and colony formation, induced apoptosis via PARP cleavage, and increased the sub-G1 population of Hep3B and Huh7 cells. In addition, CPSF6 enhanced the stability of c-Myc via their binding through nuclear co-localization by binding to c-Myc at the site of 258-360. Furthermore, c-Myc degradation by CPSF6 depletion was disturbed by FBW7 depletion or treatment with the proteasomal inhibitor MG132. Additionally, CPSF6 depletion suppressed the Warburg effect by inhibiting glucose, HK2, PKM2, LDH, and lactate; showed a synergistic effect with Sorafenib in Hep3B cells; and inhibited angiogenesis by tube formation and CAM assays, along with decreased expression and production of vascular endothelial growth factor (VEGF). Notably, CPSF6 depletion attenuated PD-L1 expression and increased Granzyme B levels, along with an increase in the percentage of CD4/CD8 cells in the splenocytes of BALB/c nude mice bearing Hep3B cells. Consistently, immunohistochemistry showed that CPSF6 depletion reduced the growth of Hep3B cells in BALB/c mice in orthotopic and xenograft tumor models by inhibiting tumor microenvironment-associated proteins. Overall, these findings suggest that CPSF6 enhances the Warburg effect for immune escape and angiogenesis, leading to cancer progression via c-Myc, mediated by the HK, PD-L1, and VEGF networks, with synergistic potential with sorafenib as a molecular target for liver cancer therapy.
在这项研究中，我们探讨了剪接多聚腺苷酸化特异性因子 6（CPSF6）在肝细胞癌（HCC）中的致癌机制。与正常组织相比，CPSF6 在 HCC 组织中高表达且患者生存率较差。因此，CPSF6 耗竭通过 PARP 切割抑制细胞活力和集落形成，诱导凋亡，并增加 Hep3B 和 Huh7 细胞的亚 G1 群体。此外，CPSF6 通过核共定位与 c-Myc 结合，在 258-360 位结合 c-Myc 增强其稳定性。此外，通过 FBW7 耗竭或用蛋白酶体抑制剂 MG132 处理，干扰 CPSF6 耗竭导致的 c-Myc 降解。此外，CPSF6 耗竭通过抑制葡萄糖、HK2、PKM2、LDH 和乳酸来抑制沃伯格效应；在 Hep3B 细胞中与索拉非尼具有协同作用；并通过管形成和 CAM 测定抑制血管生成，同时降低血管内皮生长因子（VEGF）的表达和产生。值得注意的是，CPSF6 耗竭降低 PD-L1 表达并增加颗粒酶 B 水平，同时增加 BALB/c 裸鼠荷瘤脾细胞中 CD4/CD8 细胞的百分比。免疫组化显示，CPSF6 耗竭通过抑制肿瘤微环境相关蛋白，减少 BALB/c 小鼠原位和异种移植肿瘤模型中 Hep3B 细胞的生长。总的来说，这些发现表明 CPSF6 通过 c-Myc 增强了免疫逃避和血管生成的沃伯格效应，通过 HK、PD-L1 和 VEGF 网络介导的癌症进展，与索拉非尼具有协同作用，为肝癌治疗提供了一个分子靶点。
