No abstract

Hepatocellular carcinoma (HCC) is one of the most lethal cancers worldwide because of metastasis. Epithelial‐mesenchymal transition (EMT) is widely considered to be crucial to the invasion‐metastasis cascade during cancer progression. Actin‐like 6A (ACTL6A) is initially verified important for cell proliferation, differentiation, and migration. In this study, we find that ACTL6A plays an essential role in metastasis and EMT of HCC. ACTL6A expression is up‐regulated in HCC cells and tissues. A high level of ACTL6A in HCCs is correlated with aggressive clinicopathological features and is an independent poor prognostic factor for overall and disease‐free survival of HCC patients. Ectopic expression of ACTL6A markedly promotes HCC cells migration, invasion, as well as EMT in vitro and promotes tumor growth and metastasis in the mouse xenograft model. Opposite results are observed when ACTL6A is knocked down. Mechanistically, ACTL6A promotes metastasis and EMT through activating Notch signaling. ACTL6A knockdown has the equal blockage effect as the Notch signaling inhibitor, N‐[N‐(3,5‐difluorophenacetyl)‐L‐alanyl]‐S‐phenylglycine t‐butylester, in HCC cells. Further studies indicate that ACTL6A might manipulate SRY (sex determining region Y)‐box 2 (SOX2) expression and then activate Notch1 signaling. Conclusions: ACTL6A promotes metastasis and EMT by SOX2/Notch1 signaling, indicating a prognostic biomarker candidate and a potential therapeutic target for HCC. (Hepatology 2016;63:1256–1271)

Hepatocellular carcinoma (HCC) harbors highly metastatic properties, accounting for postoperative recurrence and metastasis. However, the mechanisms for metastasis and recurrence remain incompletely clear. This study aimed to investigate the role of hsa-miR-487a (miR-487a) in promoting the proliferation and metastasis of HCC and to elucidate the underlying molecular mechanisms. 198 HCC samples were analyzed for association between miR-487a expression and patient clinicopathological features and prognosis. The roles of miR-487a in proliferation and metastasis were validated both and The upstream regulator and downstream targets of miR-487a were determined using a dual luciferase reporter assay, chromatin immunoprecipitation and immunohistochemistry. Our results demonstrate that upregulated miR-487a correlates with a poor prognosis for HCC patients. miR-487a enhances proliferation and metastasis of HCC cells by directly binding to sprouty-related EVH1 domain containing 2 (SPRED2) or phosphoinositide-3-Kinase regulatory subunit 1 (PIK3R1). Interestingly, miR-487a mainly promotes metastasis via SPRED2 induced mitogen activated protein kinase signaling and promotes proliferation via PIK3R1 mediated AKT signaling. Transcription of miR-487a was found to be activated by up-regulated heat shock factor 1, which we previously demonstrated to be an important metastasis-associated transcription factor in a previous study. Phosphorodiamidate morpholino oligomers effectively silenced miR-487a and inhibited HCC tumor progression in mouse models. Our findings show that miR-487a, mediated by heat shock factor 1, promotes proliferation and metastasis of HCC by PIK3R1 and SPRED2 binding, respectively. Our study provides a rationale for developing miR-487a as a potential prognostic marker or a potential therapeutic target against HCC. .

By comparing the expression profiles of miRNAs in different subtypes of HCC, we identified miR-424 as a HCC related miRNA. We found that the expression of miR-424 was significantly decreased in HCC tissues and six liver cancer cell lines. Significantly, its expression levels were correlated with tumor size, multiple nodules, vein invasion, TNM stage and overall survival of HCC. We showed that up-regulated miR-424 suppressed HCC cell proliferation in vivo and in vitro. Multi-pathway reporter arrays suggested that miR-424 suppressed the pRb-E2F pathway. Consistently, Akt3 and E2F3 were identified as the targets of miR-424 as evidenced by that ectopic miR-424 expression suppressed Akt3 and E2F3 expressions. Silencing Akt3 and E2F3 by siRNA pheno-copied the effect of ectopic miR-424 on HCC growth. Whereas, overexpression of Akt3 and E2F3 attenuated the effect of miR-424 on HCC growth. Together, our data demonstrated a tumor suppressor role for miR-424 in HCC development and progression with therapeutic implications. The strong correlation of miR-424 expression with HCC patient survival suggests that miR-424 could be a valuable biomarker for HCC prognosis.

MicroRNAs (miRNAs) have been identified as critical modulators of cell proliferation and growth, which are the major causes of cancer progression including hepatocellular carcinoma (HCC). Our previous miRNA microarray data have shown that miR-330-5p was always upregulated in HCC. However, the accurate role of miR-330-5p in HCC is still uncertain. Here, we report that miR-330-5p expression is upregulated in HCC tissues and cell lines, and is associated with tumor size, tumor nodule number, capsule formation and Tumor Node Metastasis (TNM) stage in HCC patients. Overexpression of miR-330-5p promotes proliferation and growth of HCC cells in vitro and in vivo, while miR-330-5p knockdown has the inverse effect. Moreover, using miRNA databases and dual luciferase report assay, we find miR-330-5p directly binds to the 3′-untranslated region (3′-UTR) of Sprouty2 (SPRY2). Then we find the novel biofunctional role of SPRY2 inactivation in promoting HCC progression. Finally, we confirm that miR-330-5p suppresses SPRY2 to promote proliferation via mitogen-activated protein kinases (MAPK)/extracellular regulated kinase (ERK) signaling in HCC. Taken together, our findings demonstrate the critical role of miR-330-5p in promoting HCC progression via targeting SPRY2 to activate MAPK/ERK signaling, which may provide a novel and promising prognostic marker and therapeutic target for HCC.