CNOT9 affects hepatocellular carcinoma proliferation and cell cycle through the PTEN/AKT/p53 signaling pathway.

Hepatocellular carcinoma (HCC) is a major health issue, but treatment options are limited. This study investigated the role of CCR4-NOT transcription complex subunit 9 (CNOT9) in the pathogenesis of HCC and its potential as a therapeutic target. Bioinformatics analysis was performed on RNA-seq data from the TCGA and GTEx databases to assess CNOT9 expression and prognostic significance. CNOT9 expression was validated in clinical samples and cell lines using qRT-PCR and Western blot. CNOT9 was knocked down in HCC cell lines, and its effects on proliferation, apoptosis, and cell cycle were investigated using functional assays (CCK-8, EdU, colony formation, and flow cytometry). The underlying molecular mechanisms were explored via RNA-seq and Western blot analysis of the AKT pathway and cell cycle regulators. Xenograft mouse models were used to confirm the oncogenic role of CNOT9 in vivo. CNOT9 mRNA and protein expression were upregulated in HCC patients and associated with poor prognosis. CNOT9 induces abnormal proliferation of HCC cells and G2/M phase cell cycle progression. Knocking down CNOT9 reduces cell proliferation, increases apoptosis, and causes cell arrest at the G2 phase. CNOT9 knockdown activates PTEN to inhibit the AKT pathway and suppresses the expression of cell cycle-related proteins p53, p21, CCNE1 and CDK2. CNOT9-deficient tumors exhibited reduced growth in mice, supporting its pro-oncogenic role. This study first elucidates the molecular mechanism by which CNOT9 drives HCC progression through post-transcriptional regulation of the PTEN/AKT/p53 axis, providing a theoretical basis for precision treatment strategies targeting CNOT9 or the PTEN/AKT/p53 pathway.