Abstract. Macrophages are a major component of the leukocyte infiltrate of tumors and play a pivotal role in the progression of hepatocellular carcinoma (HCC). However, the molecular mechanisms by which macrophages promote HCC invasion are poorly understood. The present study was undertaken to investigate the relationship between macrophages and epithelial-mesenchymal transition (EMT) of HCC. Double-staining immunohistochemistry was used to observe the association between macrophages and EMT markers in clinical HCC samples and it showed that EMT primarily occurred at the edge of the tumor nest, in which infiltrating macrophages were always observed. This indicated that CD68 which is a marker of macrophages, was correlated with EMT marker levels. In addition, after being cultured with macrophages for 24 h, the ability of HCC cells to migrate and invade increased, Snail and N-Cadherin expression was upregulated, and E-Cadherin was downregulated. An antibody array assay was applied to analyze the supernatant of these cultures and it demonstrated IL-8 increased significantly in the macrophage co-culture system. Finally, the role of macrophage-derived IL-8 in the invasion of HCC cells was assayed, and downstream signaling pathways were also investigated. We found that IL-8: i) may induce EMT and promote HCC cell migration and invasion and ii) is associated with the JAK2/STAT3/Snail signaling pathway. Taking together, these findings revealed that macrophages that have infiltrated tumors may induce epithelial-mesenchymal transition of HCC cells via the IL-8 activated JAK2/STAT3/Snail pathway. Thus, this may offer a potential target for developing new HCC therapies.

Heterogeneous ribonucleoprotein (hnRNP) A1 is a member of the A/B subfamily of ubiquitously expressed hnRNPs, which have a wide variety of functions in gene expression and signal transduction. To investigate the biological function and clinical significance of hnRNP A1 in hepatocellular carcinoma (HCC), we measured hnRNP A1 expression in four HCC cell lines and two independent cohorts of HCC patients. We found that hnRNP A1 was overexpressed in the highly metastatic HCC cell lines and in tumor tissues of patients with recurrent HCC. Knockdown of hnRNP A1 in highly metastatic HCC cells caused a significant decrease in cell invasion, while upregulation of hnRNP A1 in poorly metastatic HCC cells led to a significant increase in their invasive capacity. We found that this effect may occur through the regulation of CD44v6 expression by hnRNP A1 in HCC cells. Both quantitative reverse transcription-polymerase chain reaction (qRT-RCR) and immunohistochemistry revealed that hnRNP A1 was upregulated in HCC tissues and coincided with overexpression of CD44v6. HCC patients with high hnRNP A1 tended to have higher levels of CD44v6, shorter overall survival (OS) and higher rates of tumor recurrence. Multivariate analyses revealed that hnRNP A1 alone or in combination with CD44v6 were independent prognostic indicators for OS and time to recurrence and have potential as therapeutic targets. In conclusion, overexpression of hnRNP A1 promotes HCC invasion by regulating the level of CD44v6 and indicates a poor prognosis for HCC patients after curative resection.Hepatocellular carcinoma (HCC) is one of the most common and aggressive human malignancies worldwide. 1 The prognosis of HCC remains dismal due to the high rate of tumor recurrence and metastasis after curative resection. 1,2 The molecular pathogenesis and complicated signal transduction pathways involved in HCC are not fully understood. Although several molecular markers that may define the risk of recurrence and the metastatic potential of HCC have been proposed, none have been approved for routine clinical use. 3,4 Heterogeneous ribonucleoproteins (hnRNPs) are a set of nuclear proteins that bind to nascent transcripts produced by RNA polymerase II and have a wide range of roles in DNA repair, telomere biogenesis, cell signaling and regulating gene expression at both transcriptional and translational levels. 5 Emerging evidence suggests that some hnRNPs (including hnRNP A2B1, 6-8 hnRNP M4 9 and hnRNP K 10 ) are essential factors in tumor development and progression. 11 HnRNP A1 is a member of the A/B subfamily of ubiquitously expressed hnRNPs, which have a wide variety of functions. It is involved in telomere biogenesis; the telomeres of an hnRNP A1-deficient cell line are shorter than those of a related normal hnRNP A1-expressing cell line. 12 This hnRNP is also involved in protein-protein interactions, and through its N-terminal RNA-binding domain, interacts with inhibitory subunit of NF-jB alpha (IjBa), resulting in the activation of nuclear factor j B (NF-jB). 13 Rec...

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