The APC/C subunit APC7 promotes hepatocellular carcinoma progression by mediating ubiquitination and degradation of LATS1 to activate YAP/TAZ

Abstract Background The anaphase-promoting complex/cyclosome (APC/C) is a multi-subunit E3 ubiquitin ligase critically involved in cell cycle regulation. However, the pathological functions of its individual subunits, particularly in hepatocellular carcinoma (HCC), remain largely unexplored. Aim To systematically analyze the expression and prognosis of APC/C in pan-cancer, and also focus on studying the function and mechanism of APC7 in the progression of HCC. Methods Transcriptome data were downloaded from TCGA, ICGC, and GEO databases. The analysis of differential expression genes and clinical characteristics were performed to identify the key APC gene. Moreover, immune subtype analysis was conducted to elucidate potential functions, and immune cell infiltration was assessed using the CIBERSORT algorithm. Then, gain- and loss‐of‐function studies were employed to elucidate the role of APC7 in HCC. Finally, RNA sequencing and ubiquitination assays were employed to elucidate the underlying mechanisms of APC7 in HCC. Results This study systematically analyzed the expression and prognosis of various subunits of the APC/C complex in pan-cancer samples, and identified APC7 as a key subunit in HCC. APC7 exhibited the most significant upregulation in HCC and was closely associated with poor prognosis in patients. Moreover, the expression profiles of APC7 is closely related to immune checkpoint genes and tumor-infiltrating immune cells. The results of multiplex immunohistochemistry showed that APC7 overexpression markedly increased the infiltration of Foxp3⁺, CD25⁺, and CD4⁺ Treg cells. Functional studies demonstrated that the knockdown of APC7 inhibited HCC cell proliferation, migration, invasion, and G1/S phase transition, whereas overexpression of APC7 promoted these malignant phenotypes in vitro and in vivo. Mechanistically, RNA sequencing and molecular studies revealed that APC7 interacts with CDH1 to mediate ubiquitin-dependent degradation of LATS1 at K860, leading to YAP/TAZ activation. Rescue experiments confirmed that LATS1 ablation reversed the tumor-suppressive effects of APC7 knockdown. Conclusions Our findings identify APC7 as a key oncogenic driver in HCC, promoting tumor progression via the Hippo signaling pathway. APC7 may represent a prognostic biomarker and a potential therapeutic target in HCC.