Background: LncRNA is a key factor influencing tumor development. The present study aimed to investigate the effect of a novel lncRNA on the progression of hepatocellular carcinoma (HCC). Methods: A candidate lncRNA in The Cancer Genome Atlas database was identified using limma and survival R packages. The effect of lncRNA AC099850.3 on cell proliferation, apoptosis, migration, and invasion, as well as its association with immune cells in HCC were investigated. Furthermore, the functional mechanisms of lncRNA AC099850.3 in HCC were elucidated. Results:The aberrant expression of lncRNA AC099850.3 was identified in tumor tissues and its prognostic relevance in HCC was determined. The results revealed that AC099850.3 was highly expressed in HCC tissues and cell lines, and it predicted poor prognosis in patients with HCC. Furthermore, knockdown of AC099850.3 significantly suppressed the proliferation and metastatic potential of HCC cells, and promoted cell apoptosis in HCC cells. The results of gene set enrichment analysis revealed that the PI3K/AKT pathway was associated with the biological function of AC099850.3, which was further validated by western blotting. PRR11 was identified as the target gene of AC099850.3 and we established that AC099850.3 acted as an oncogene in the PRR11/PI3K/AKT axis. Immune cell infiltration analyses results revealed that AC099850.3 was positively correlated with T follicular helper cells, M0 macrophages, CD4 + memory T cells, and memory B cells. Conversely, AC099850.3 was negatively correlated with M2 macrophages, monocytes, natural killer cells, and CD8 + T cells, which could be responsible for its oncogenic effect. Of note, a significantly positive correlation was observed between AC099850.3 and key immune checkpoint molecules (PD-1, PD-L1, PD-L2, and CTLA4) in the present study, making AC099850.3 a potential immune therapeutic target for HCC. Conclusion: AC099850.3 can promote malignant biological behavior of HCC cells, and could be a potential biomarker and therapeutic target for HCC.

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Tumour metastasis is the main cause of postoperative tumour recurrence and mortality in patients with hepatocellular carcinoma (HCC), but the underlying mechanism remains unclear. Accumulating evidence has demonstrated that programmed cell death 10 (PDCD10) plays an important role in many biological processes. However, the role of PDCD10 in HCC progression is still elusive. In this study, we aimed to explore the clinical significance and molecular function of PDCD10 in HCC. PDCD10 is significantly upregulated in HCC, which also correlates with aggressive clinicopathological characteristics and predicts poor prognosis of HCC patients after liver resection. High PDCD10 expression promotes HCC cell proliferation, migration, and invasion in vitro and tumour growth, metastasis in vivo. In addition, PDCD10 could facilitate epithelial-to-mesenchymal transition (EMT) of HCC cells. In terms of the mechanism, PDCD10 directly binds to the catalytic subunit of protein phosphatase 2A (PP2Ac) and increases its enzymatic activity, leading to the interaction of YAP and dephosphorylation of the YAP protein. This interaction contributes to YAP nuclear translocation and transcriptional activation. PP2Ac is necessary for PDCD10-mediated HCC progression. Knocking down PP2Ac abolished the tumour-promoting role of PDCD10 in the migration, invasion and EMT of HCC. Moreover, a PP2Ac inhibitor (LB100) could restrict tumour growth and metastasis of HCC with high PDCD10 expression. Collectively, PDCD10 promotes EMT and the progression of HCC by interacting with PP2Ac to promote YAP activation, which provides new insight into the mechanism of cancer metastasis. PDCD10 may be a potential prognostic biomarker and therapeutic target for HCC.

Background Piezo1 has been revealed to play a regulatory role in vascular development and progression of variety tumors. However, whether and how the progression of hepatocellular carcinoma (HCC) regulated by Piezo1 remains elusive. This study aimed to elucidate the effect and mechanisms of Piezo1 in HCC. Methods The mRNA and protein expression level of Piezo1 in HCC samples and cell lines was determined by qRT-PCR, western blot and immunohistochemistry analyses. Two independent study cohorts containing 280 patients were analyzed to reveal the association between Piezo1 expression and clinicopathological characteristics. Series of in vitro and in vivo experiments were used to validate the function of Piezo1 in HCC. Gene set enrichment analysis (GSEA) was performed to explore the signaling pathway of Piezo1. Immunoprecipitation, immunofluorescence and in vitro and in vivo experiments were used to explore the molecular mechanism of Piezo1 in HCC progression. Results Our results demonstrated the Piezo1 expression was significantly upregulated in HCC tissues and cell lines, and upregulation of Piezo1 closely correlated with aggressive clinicopathological features and poor prognosis. Knockdown of Piezo1 in HCCLM3 and Hep3B cells significantly restrained proliferation, migration, invasion and epithelial–mesenchymal transition (EMT) of HCC cells in vitro, and tumor growth, metastasis, EMT in vivo. TGF-β signaling pathway was most significant enriched pathway in GSEA. Finally, tumor promotion effect of Piezo1 was found to exerted through recruiting and combining Rab5c to activating TGF-β signaling pathway. Conclusions Piezo1 significantly related to poor prognosis and promotes progression of hepatocellular carcinoma via activating TGF-β signaling, which suggesting that Piezo1 may serve as a novel prognostic predictor and the potential therapeutic target for HCC patients.

Gαq subfamily proteins play critical roles in many biological functions including cardiovascular development, angiogenesis and tumourgenesis of melanoma. However, the understanding of G Protein Subunit Alpha 14(GNA14) in diseases, especially in cancers is limited. Here, we revealed that GNA14 was significantly low-expression in human Hepatocellular Carcinoma (HCC) samples. Low GNA14 expression was correlated with aggressive clinicopathological features. Moreover, the overall survival (OS) and disease-free survival (DFS) of high GNA14 expression HCC patients were much better than low GNA14 expression group. Lentivirus-mediated GNA14 knockdown significantly promoted the growth of liver cancer in vitro and in vivo. However, opposing results were observed when GNA14 is up-regulated. Mechanistically, We identified Receptor For Activated C Kinase 1 (RACK1) as a binding partner of GNA14 by coimmunoprecipitation (co-IP) and mass spectrometry (MS). Glutathione-S-transferase (GST) pull-down assay further verified the direct interaction between GNA14 and RACK1. RNA-Seq and loss- and gain-of-function assays also confirmed that GNA14 reduced the activity of both MAPK/JNK and PI3K/AKT signaling pathways through RACK1. GNA14 synergized with U73122 (PLC inhibitor) to enhance this effect. Further studies suggested that GNA14 potentially competed with Protein Kinase C (PKC) to bind with RACK1, consequently reducing the stability of PKC. Moreover, we also showed that GNA14’supression of p-AKT protein level depended on sufficient RACK1 expression. In conclusion, we indicated a different role of GNA14, which acted as a suppressor inhibiting liver cancer progression through MAPK/JNK and PI3K/AKT signaling pathways. Due to this, GNA14 served as a potentially valuable prognostic biomarker for liver cancer.