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Genetic and epigenetic silencing of SCARA5 may contribute to human hepatocellular carcinoma by activating FAK signaling.

ABSTRACT: The epigenetic silencing of tumor suppressor genes is a crucial event during carcinogenesis and metastasis. Here, in a human genome-wide survey, we identified scavenger receptor class A, member 5 (SCARA5) as a candidate tumor suppressor gene located on chromosome 8p. We found that SCARA5 expression was frequently downregulated as a result of promoter hypermethylation and allelic imbalance and was associated with vascular invasion in human hepatocellular carcinoma (HCC). Furthermore, SCARA5 knockdown via RNAi markedly enhanced HCC cell growth in vitro, colony formation in soft agar, and invasiveness, tumorigenicity, and lung metastasis in vivo. By contrast, SCARA5 overexpression suppressed these malignant behaviors. Interestingly, SCARA5 was found to physically associate with focal adhesion kinase (FAK) and inhibit the tyrosine phosphorylation cascade of the FAK-Src-Cas signaling pathway. Conversely, silencing SCARA5 stimulated the signaling pathway via increased phosphorylation of certain tyrosine residues of FAK, Src, and p130Cas; it was also associated with activation of MMP9, a tumor metastasis-associated enzyme. Taken together, these data suggest that the plasma membrane protein SCARA5 can contribute to HCC tumorigenesis and metastasis via activation of the FAK signaling pathway.

SUBMITTER: Huang J

PROVIDER: S-EPMC2798676 | biostudies-literature | 2010 Jan

REPOSITORIES: biostudies-literature

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Genetic and epigenetic silencing of SCARA5 may contribute to human hepatocellular carcinoma by activating FAK signaling.

Huang Jian J Zheng Da-Li DL Qin Feng-Song FS Cheng Na N Chen Hui H Wan Bing-Bing BB Wang Yu-Ping YP Xiao Hua-Sheng HS Han Ze-Guang ZG

The Journal of clinical investigation 20091214 1

The epigenetic silencing of tumor suppressor genes is a crucial event during carcinogenesis and metastasis. Here, in a human genome-wide survey, we identified scavenger receptor class A, member 5 (SCARA5) as a candidate tumor suppressor gene located on chromosome 8p. We found that SCARA5 expression was frequently downregulated as a result of promoter hypermethylation and allelic imbalance and was associated with vascular invasion in human hepatocellular carcinoma (HCC). Furthermore, SCARA5 knock ...[more]

PMID: 20038795

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Project description:BACKGROUND:The role of TMEM176A in human hepatocellular carcinoma (HCC) is unknown. This study explored the epigenetic regulation and function of TMEM176A in human HCC. MATERIALS AND METHODS:Twelve HCC cell lines and 126 cases of primary cancer were analyzed. Methylation-specific PCR, immunohistochemistry, flow cytometry, and xenograft mouse models were employed. RESULTS:TMEM176A was highly expressed in SNU387, SNU182, Huh1, and SNU475 cells; reduced expression was observed in HepG2 and PLC/PRF/5 cells; and no expression was found in SNU449, HBXF344, SMMC7721, Huh7, and LM3 cells. Unmethylation of the TMEM176A promoter was detected in SNU387, SNU182, Huh1, and SNU475 cells; partial methylation was observed in HepG2 and PLC/PRF/5 cells; and complete methylation was found in SNU449, HBXF344, SMMC7721, Huh7, and LM3 cells. Upon treatment with 5-Aza-2-deoxycytidine, re-expression of TMEM176A was detected in SNU449, HBXF344, SMMC7721, Huh7, and LM3 cells; increased expression of TMEM176A was observed in HepG2 and PLC/PRF/5 cells; and no expression changes were found in SNU387, SNU182, Huh1, and SNU475 cells. The TMEM176A promoter region was methylated in 75.4% (95/126) of primary human HCC. Reduced expression of TMEM176A was associated with promoter region methylation (P?<?0.05). No association was found between TMEM176A promoter methylation and age, gender, HBV infection, liver cirrhosis, tumor size, lymph node metastasis, vessel cancerous embolus, number of lesions, and TNM stage (all P?>?0.05). These results demonstrated that the expression of TMEM176A is regulated by promoter region methylation. Methylation of the TMEM176A promoter was significantly associated with tumor cell differentiation (P?<?0.05) and was an independent prognostic factor for poor 3-year overall survival (OS, P <?0.05). TMEM176A expression induced cell apoptosis; inhibited cell proliferation, migration, and invasion; suppressed human HCC cell xenograft growth in mice; and inhibited ERK signaling in HCC cells. CONCLUSION:The promoter region of TMEM176A is frequently methylated in human HCC, and the expression of TMEM176A is regulated by promoter region methylation. Methylation of the TMEM176A promoter may serve as a diagnostic and prognostic marker in HCC. TMEM176A suppresses HCC growth by inhibiting the ERK signaling pathway.

Project description:Hepatocellular carcinoma (HCC) is a malignant tumor with a high metastatic rate. Recent studies have shown that the mitosis‑associated spindle‑assembly checkpoint regulatory protein spindle pole body component 25 homolog (SPC25) promotes HCC progression, although the underlying mechanism has yet to be fully elucidated. The aim of the present study was to investigate the mechanism through which SPC25 may promote HCC progression in greater detail. First, the expression of SPC25 was analyzed in publicly available databases to explore the association between SPC25 and HCC metastasis. Western blotting was subsequently performed to examine the level of SPC25 expression in different HCC cell lines. SPC25 was then silenced in HCCLM3 and Huh7 cells, and the effects of SPC25 silencing were investigated using cell proliferation, wound‑healing, Transwell migration assays and an in vivo mouse model. Finally, the mechanism of SPC25 action with respect to the promotion of HCC metastasis was explored using microarray analysis and rescue experiments. The results obtained demonstrated that SPC25 is highly expressed in HCC, and this high level of expression is associated with poor prognosis and metastasis. Moreover, SPC25 silencing led to a marked inhibition of the invasion and migration of HCC cells both in vitro and in vivo. The gene‑expression profiling and mechanistic experiments suggest that SPC25 preferentially influences the expression of genes associated with extracellular matrix (ECM)‑integrin interactions, including integrin subunit β4 (ITGB4), an upstream element of the integrin pathway. ITGB4 upregulation partly reversed the decline in cell invasion and migration capacities that resulted from SPC25 silencing. Furthermore, deleting both SPC25 and ITGB4 caused a decrease in the phosphorylation of focal adhesion kinase (FAK), phosphoinositide 3‑kinase (PI3K) and AKT, which are downstream elements of the integrin pathway. Taken together, the results of the present study demonstrated the important role of SPC25 as a prognostic indicator and as a promoter of metastasis in HCC, and the underlying mechanism of its action has been partially elucidated, suggesting that SPC25 could be used as a biomarker and as a target for therapeutic intervention in the treatment of HCC.

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Project description:Background: In addition to protein tyrosine kinases, accumulating evidence has shown that protein tyrosine phosphatases (PTPs) are suitable therapeutic targets in cancer. PRL-3 is a PTP member that has been well studied in many malignant tumours. The goal of the present study was to elucidate the role of PRL-3 in hepatocellular carcinoma (HCC), which remains largely unknown. Methods: Bioinformatic and immunohistochemical analyses were performed to analyse PRL-3 expression in HCC tissue samples and determine its clinical relevance. PRL-3 gene copy number variations were evaluated by bioinformatic analysis and quantitative-genomic polymerase chain reaction. The biological functions of PRL-3 were investigated in vivo and vitro. Gene microarray assays, RT-qPCR, western blotting and luciferase experiments were performed to identify the downstream effectors of PRL-3 that mediate its functions in HCC. Results: PRL-3 expression was upregulated in HCC samples from public databases and in cohort samples from our centre. High PRL-3 expression was associated with poor prognosis. Copy number gains and amplification of chromosome 8q24.3 in HCC were determined to be positively correlated with the PRL-3 overexpression. PRL-3 overexpression promoted HCC cell proliferation, migration and adhesion, while its loss had the opposite effects. Further study showed that focal adhesion kinase (FAK) was co-amplified and co-expressed with PRL-3 in HCC. Interestingly, PRL-3 also promoted the phosphorylation of FAK, which subsequently mediated the oncogenic functions of PRL-3 in HCC cells. Moreover, TGFB1 was identified as a downstream molecule of PRL-3. TGF-β signalling was shown to mediate the PRL-3-induced activation of FAK. Furthermore, the p38 and PI3K/AKT pathways were observed to mediate the PRL-3-induced expression of TGFB1 and the subsequent activation of FAK, while the activation of FAK in turn stimulated activation of the p38 and PI3K/AKT pathways, forming a PRL-3-triggered AKT/p38/TGFB1/FAK positive feedback loop. Conclusion: Collectively, our findings indicate that the PTP PRL-3 plays a crucial role in the progression of HCC and provides an example of how co-amplified genes work together in HCC.

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Genetic and epigenetic silencing of SCARA5 may contribute to human hepatocellular carcinoma by activating FAK signaling.

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Genetic and epigenetic silencing of SCARA5 may contribute to human hepatocellular carcinoma by activating FAK signaling.

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