Molecular Characteristics of Aberrant Gene Mutations and Expression Profiles Induced by Benzo(a)pyrene in Hepatocellular Carcinoma Cells.

Benzo(a)pyrene (BaP) is a prevalent food and environmental carcinogen. Chronic low-dose BaP exposure can promote the migratory and invasive capacities of human hepatocellular carcinoma (HCC) cells, yet its intricate molecular mechanisms remain elusive. Utilizing the established BaP-exposed HCC cell model, we analyzed the gene expression alteration, exosomal RNA cargo, and genetic variants induced by BaP through transcriptomic and whole-genome sequencing. Transcriptomic analysis revealed significant dysregulation in genes and pathways associated with tumor metastasis, particularly those involved in steroidal lipid metabolism and cell migration. BaP exposure enriched PI3K-AKT, mTOR, and NF-κB signaling pathways and disrupted genes implicated in cellular secretory processes, suggesting the potential involvement of exosomes in metastasis. Exosome analysis depicted the RNA profiling in exosomes of HCC cells altered by BaP, and the exosomal circRNA-miRNA-mRNA interaction network was constructed. Finally, whole-genome sequencing delineated BaP-induced gene mutations and genomic instability in HCC cells. In summary, prolonged low-dose BaP exposure induces intricate molecular alterations in gene mutation and expression profiles in HCC cells, notably those secreted in exosomes, which may potentially remodel the tumor microenvironment and foster HCC metastasis. Our findings offer new insights into the molecular underpinnings of BaP-induced HCC metastasis, thereby advancing the comprehensive understanding of BaP toxicity.

GSN synergies with actin-related transfer molecular chain to promote invasion and metastasis of HCC.

BACKGROUND: Previous studies have shown that the ability of tumor cells to move and migrate is related to the molecular chain pathway mediated by actin. This study focused on the molecular mechanism of gelsolin (GSN) as an important actin-binding protein in promoting HCC invasion and metastasis. METHODS: The relationship between GSN expression and clinical characteristics was observed by immunohistochemistry (IHC). In vitro and in vivo experiments confirmed the role of GSN in HCC metastasis. Dual-immunoprecipitation (IP), immunofluorescence (IF), western blotting, and the gelatinase activity assay were used to investigate the mechanism of GSN-promoting metastasis. PEX fusion proteins were used to intervene in the transfer molecular chain. RESULTS: Our study found that GSN promoted HCC invasion and metastasis through its synergistic effect with actin-related transfer molecular chain (actin-CD44-MMPs). Concretely, as an important binding molecule of actin, GSN activated MMP2 by interacting with MMP14. Furthermore, CD44 might be a key node in the above-mentioned mechanism. The use of MMP14 domain (PEX fusion protein) to competitively bind to CD44 helped to inhibit the activation of downstream MMP2. CONCLUSIONS: GSN played crucial roles in HCC metastatic process. An improved understanding of the multiple effects of GSN in HCC might facilitate a deeper appreciation of GSN as an important HCC regulator. The study identified GSN and its regulated transfer molecular chain as potential therapeutic targets for HCC.

Hepatitis C Virus Core Protein Promotes the Metastasis of Human Hepatocytes by Activating the MAPK/ERK/PEA3-SRF/c-Fos/MMPs Axis.

BACKGROUND AND AIM: Previous studies have shown that the hepatitis C virus (HCV) core protein plays an important role in the metastasis of hepatocellular carcinoma (HCC) cells. This study aimed to identify the potential mechanism of HCV core protein in HCC. METHODS: A transcription factor microarray analysis was performed to identify the factors regulated by the HCV core protein. A comprehensive bioinformatics analysis approach was utilized to predict the functions, regulatory signaling pathways and downstream target genes of the differentially regulated transcription factors. Dual-luciferase assays, qPCR, Western blotting, ERK pathway inhibition experiments and siRNA knockdown experiments were performed to verify the effects of the HCV core protein on PEA3, SRF and c-Fos, as well asthe underlying mechanism. The migration/invasion assay and scratch assay served to confirm the metastasis-promoting mechanism of the HCV core protein. RESULTS: The results demonstrated that altered expression of PEA3, SRF and c-Fos mediated by the HCV core protein were associated with the MAPK/ERK pathway. c-Fos was a downstream target protein of PEA3 and SRF. Knockdown of PEA3-SRF/c-Fos expression and ERK pathway components suppressed the migration and invasion activity of hepatocytes by affecting MMP2 and MMP9 expression. CONCLUSION: We provided preliminary evidence that the role of the HCV core protein in promoting metastasis is at least partially dependent on the activation of the MAPK/ERK/PEA3-SRF/c-Fos/MMP2/MMP9 axis. These findings reveal a novel mechanism by which the HCV core protein promotes HCC metastasis and may provide new therapeutic targets for patients with metastatic HCC.

27-Hydroxycholesterol promotes metastasis by SULT2A1-dependent alteration in hepatocellular carcinoma.

Oxysterol metabolism plays an important role in the initiation and development of various tumors. However, little is known that the metabolic alternation can promote the metastasis of hepatocellular carcinoma (HCC). In this study, we identify the sulfotransferase family 2A member 1 (SULT2A1) to 27-hydroxycholesterol (27-OHC) metabolic axis as playing a critical role in HCC metastasis. The level of 27-OHC closely corresponded with HCC metastasis instead of proliferation in vitro and in vivo. Also, the expression of SULT2A1 is extremely downregulated in human HCC tissues and is correlated with poor prognosis and tumor metastasis. Gain- and loss-of-function studies reveal that SULT2A1 suppresses the metastasis of HCC by regulating the level of 27-OHC. Further mechanistic studies indicated that SULT2A1-dependent alternation of 27-OHC activates the nuclear factor-κB signaling pathway and promotes HCC metastasis by enhancing Twist1 expression and epithelial-mesenchymal transition. In conclusion, our findings indicate the relationship between the metabolism of 27-OHC and the metastasis of HCC. Moreover, SULT2A1 could act as a potential prognostic biomarker and a therapeutic target for preventing HCC metastasis.

TDP-43 induces EMT and promotes hepatocellular carcinoma metastasis via activating Wnt/ß-catenin signaling pathway.

The trans-activation response DNA-binding protein of 43 kDa (TDP-43) is a nuclear protein that has been shown to be involved in the growth and metastasis of breast cancer, neuroblastoma, and melanoma. However, the effect of TDP-43 on hepatocellular carcinoma (HCC) metastasis remains unclear. Here, we demonstrated that TDP-43 was highly upregulated in both clinical samples and cell lines of HCC. Moreover, knockdown and overexpression of TDP-43 efficiently affected the proliferation and metastasis of HCC cells as well as the expression of some proteins associated with epithelial-mesenchymal transition (EMT) and Wnt/ß-catenin signaling pathway. Furthermore, activation of the Wnt/ß-catenin pathway by LiCl restored the effect of TDP-43 knockdown on EMT and HCC cells, whereas inhibition of the Wnt/ß-catenin pathway by XAV939 negated the effect of TDP-43 overexpression. Importantly, we found that TDP-43 protein could interact with GSK3ß mRNA and regulate the level of GSK3ß protein translation. Taken together, our findings suggest that TDP-43 may activate the Wnt/ß-catenin pathway by targeting the inhibition of GSK3ß protein translation, thus inducing the proliferation and metastasis of HCC cells, which supports its potential value as a therapeutic target for the treatment of metastatic HCC.

Bioinformatic Analysis to Identify a Multi-mRNA Signature for the Prediction of Metastasis in Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) with metastasis indicates worse prognosis for patients. However, the current methods are insufficient to accurately predict HCC metastasis at early stage. Based on the expression profiles of three Gene Expression Omnibus datasets, the differentially expressed genes associated with HCC metastasis were screened by online analytical tool GEO2R and weighted gene co-expression network analysis. Second, a risk score model including 27-mRNA was established by univariate Cox regression analyses, time-dependent ROC curves and least absolute shrinkage and selection operator Cox regression analysis. Then, we validated the model in cohort The Cancer Genome Atlas-liver hepatocellular carcinoma and analyzed the functions and key signaling pathways of the genes associated with the risk score model. According to the risk score model, patients were divided into two subgroups (high risk and low risk groups). The metastasis rate between two subgroups was significantly different in training cohort (p < 0.0001, hazard ratio [HR]: 10.3, confidence interval [95% CI]: 6.827-15.55) and external validation cohort (p = 0.0008, HR: 1.768, 95% CI: 1.267-2.467). Multivariable analysis showed that the risk score model was superior to and independent of other clinical factors (such as tumor stage, tumor size, and other parameters) in predicting early HCC metastasis. Moreover, the risk score model could predict the overall survival of patients with HCC. Finally, most of 27-mRNA were enriched in exosome and membrane bounded organelle, and these were involved in transportation and metabolic biological process. Protein-protein interaction network analysis showed most of these genes might be key genes affecting the progression of HCC. In addition, 3 genes of 27-mRNA were also differentially expressed in peripheral blood mononuclear cell. In conclusion, by using two combined methods and a broader of HCC datasets, our study provided reliable and superior predictive model for HCC metastases, which will facilitate individual medical management for these high metastatic risk HCC patients.

Overexpression of p62/IMP2 can Promote Cell Migration in Hepatocellular Carcinoma via Activation of the Wnt/ß-Catenin Pathway.

p62/IMP2 is an oncofetal protein that was first reported as a tumor-associated antigen in hepatocellular carcinoma (HCC). In our previous studies, we demonstrated a high frequency of p62/IMP2 autoantibodies appearing in various types of cancer. Therefore, we hypothesize that p62/IMP2 plays an important role in the progression of HCC, although the mechanism remains to be explored. In this study, we evaluated the expression of p62/IMP2 protein both in human tissues and liver cancer cell lines by immunohistochemistry and western blotting analysis and found that p62/IMP2 protein is overexpressed in human HCC tissue in comparison to normal human liver tissue. To explore the role that p62/IMP2 plays in HCC, p62/IMP2 was knocked out in two p62/IMP2-positive liver cancer cell lines (SNU449 and HepG2). Due to the low expression level of p62/IMP2 in SNU449, we overexpressed p62/IMP2 in this cell line. We subsequently demonstrated that high expression of p62/IMP2 in both cell lines can promote cell migration and invasion abilities in vitro by activating the Wnt/ß-catenin pathway. We also used the Wnt/ß-catenin pathway inhibitor, XAV 939, and a phosphoproteome assay to confirm our findings. Conclusion: Our results suggest that p62/IMP2 is an essential regulator of Wnt signaling pathways and plays an important role in HCC progression and metastasis.