Dysregulation of PARP10 has been implicated in various tumor types and plays a vital role in delaying hepatocellular carcinoma (HCC) progression. However, the mechanisms controlling the expression and activity of PARP10 in HCC remain mostly unknown. The crosstalk between PLK1, PARP10, and NF-κB pathway in HCC was determined by performing different in vitro and in vivo assays, including mass spectrometry, kinase, MARylation, chromatin immunoprecipitation, and luciferase reporter measurements. Functional examination was performed by using small chemical drug, cell culture, and mice HCC models. Correlation between PLK1, NF-κB, and PARP10 expression was determined by analyzing clinical samples of HCC patients with using immunohistochemistry. PLK1, an important regulator for cell mitosis, directly interacts with and phosphorylates PARP10 at T601. PARP10 phosphorylation at T601 significantly decreases its binding to NEMO and disrupts its inhibition to NEMO ubiquitination, thereby enhancing the transcription activity of NF-κB toward multiple target genes and promoting HCC development. In turn, NF-κB transcriptionally inhibits the PARP10 promoter activity and leads to its downregulation in HCC. Interestingly, PLK1 is mono-ADP-ribosylated by PARP10 and the MARylation of PLK1 significantly inhibits its kinase activity and oncogenic function in HCC. Clinically, the expression levels of PLK1 and phosphor-p65 show an inverse correlation with PARP10 expression in human HCC tissues. These findings are the first to uncover a PLK1/PARP10/NF-κB signaling circuit that underlies tumorigenesis and validate PLK1 inhibitors, alone or with NF-κB antagonists, as potential effective therapeutics for PARP10-expressing HCC.

PARP10 的失调与多种肿瘤类型有关，并在延缓肝细胞癌 (HCC) 进展方面发挥着至关重要的作用。然而，控制 HCC 中 PARP10 表达和活性的机制仍然未知。 HCC 中 PLK1、PARP10 和 NF-κB 通路之间的串扰通过进行不同的体外和体内测定来确定，包括质谱、激酶、MARylation、染色质免疫沉淀和荧光素酶报告基因测量。采用小化学药物、细胞培养和小鼠肝癌模型进行功能检查。通过使用免疫组织化学分析 HCC 患者的临床样本来确定 PLK1、NF-κB 和 PARP10 表达之间的相关性。 PLK1 是细胞有丝分裂的重要调节因子，在 T601 处直接与 PARP10 相互作用并磷酸化。 PARP10 T601 的磷酸化显着降低其与 NEMO 的结合，并破坏其对 NEMO 泛素化的抑制，从而增强 NF-κB 对多个靶基因的转录活性，促进 HCC 的发展。反过来，NF-κB 转录抑制 PARP10 启动子活性并导致其在 HCC 中下调。有趣的是，PLK1 被 PARP10 单 ADP 核糖基化，并且 PLK1 的 MAR 化显着抑制其激酶活性和 HCC 中的致癌功能。临床上，人肝癌组织中PLK1和磷-p65的表达水平与PARP10的表达呈负相关。这些发现首次揭示了肿瘤发生的 PLK1/PARP10/NF-κB 信号通路，并验证了 PLK1 抑制剂（单独使用或与 NF-κB 拮抗剂联合使用）作为表达 PARP10 的 HCC 的潜在有效疗法。