Bioinformatics analysis of the proteins interacting with LASP-1 and their association with HBV-related hepatocellular carcinoma

Hepatitis B virus core protein promotes the expression of neuraminidase 1 to facilitate hepatocarcinogenesis

Neuraminidase 1 (NEU1) has been reported to be associated with hepatocellular carcinoma (HCC). However, the function and associated molecular mechanisms of NEU1 in hepatitis B virus (HBV)-related HCC have not been well investigated. In the present study, the expression of NEU1 mediated by HBV and HBV core protein (HBc) was measured in hepatoma cells. The expression of NEU1 protein was detected via immunohistochemical analysis in HBV-associated HCC tissues. The role of NEU1 in the activation of signaling pathways and epithelial-mesenchymal transition (EMT) and the proliferation and migration of hepatoma cells mediated by HBc was assessed. We found that NEU1 was upregulated in HBV-positive hepatoma cells and HBV-related HCC tissues. HBV promoted NEU1 expression at the mRNA and protein level via HBc in hepatoma cells. Mechanistically, HBc was able to enhance the activity of the NEU1 promoter through NF-κB binding sites. In addition, through the increase in NEU1 expression, HBc contributed to activation of downstream signaling pathways and EMT in hepatoma cells. Moreover, NEU1 facilitated the proliferation and migration of hepatoma cells mediated by HBc. Taken together, our findings provide novel insight into the molecular mechanism underlying the oncogenesis mediated by HBc and demonstrate that NEU1 plays a vital role in HBc-mediated functional abnormality in HCC. Thus, NEU1 may serve as a potential therapeutic target in HBV-associated HCC.

Bioinformatics analysis on multiple Gene Expression Omnibus datasets of the hepatitis B virus infection and its response to the interferon-alpha therapy

Background

Hepatitis B virus (HBV) infection is a global health problem and interferon-alpha (IFN-α) is one of the effective therapies. However, little is known about the genetic background of the HBV infection or the genetic determinants of the IFN-α treatment response. Thus, we aim to explore the possible molecular mechanisms of HBV infection and its response to the IFN-α therapy with a comprehensive bioinformatics analysis.

Methods

The Gene Expression Omnibus datasets (GSE83148, GSE84044 and GSE66698) were collected and the differentially expressed genes (DEGs), key biological processes and intersecting pathways were analyzed. The expression of the co-expressed DEGs in the clinical samples was verified by quantitative real time polymerase chain reaction (qRT-PCR).

Results

Analysis of all the 3 datasets revealed that there were eight up-regulated and one down-regulated co-expressed DEGs following the HBV infection and after IFN-α treatment. In clinical samples, the mRNA level of HKDC1, EPCAM, GSN, ZWINT and PLD3 were significantly increased, while, the mRNA level of PLEKHA2 was significantly decreased in HBV infected liver tissues compared to normal liver tissues. PI3K-Akt signaling pathway, focal adhesion, HTLV-I infection, cytokine-cytokine receptor interaction, metabolic pathways, NF-κB signaling pathway were important pathways associated with the HBV infection and the response of IFN-α treatment.

Conclusions

The co-expressed genes, common biological processes and intersecting pathways identified in the study might play an important role in HBV infection and response of IFN-α treatment. The dysregulated genes may act as novel biomarkers and therapeutic targets for HBV.

New Frontiers for the Cytoskeletal Protein LASP1

In the recent two decades, LIM and SH3 protein 1 (LASP1) has been developed from a simple actin-binding structural protein to a tumor biomarker and subsequently to a complex, nuclear transcriptional regulator. Starting with a brief historical perspective, this review will mainly compare and contrast LASP1 and LASP2 from the angle of the newest data and importantly, examine their role in transcriptional regulation. We will summarize the current knowledge through pictorial models and tables including the roles of different microRNAs in the differential regulation of LASP1 levels and patient outcome rather than specify in detail all tumor entities. Finally, the novel functional roles of LASP1 in secretion of vesicles, expression of matrix metalloproteinases and transcriptional regulation as well as the activation of survival and proliferation pathways in different cancer types are described.

Analysis of Transcription Factor-Related Regulatory Networks Based on Bioinformatics Analysis and Validation in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) accounts for a significant proportion of liver cancer, which has become the second most common cause of cancer-related mortality worldwide. To investigate the potential mechanisms of invasion and progression of HCC, bioinformatics analysis and validation by qRT-PCR were performed. We found 237 differentially expressed genes (DEGs) including EGR1, FOS, and FOSB, which were three cancer-related transcription factors. Subsequently, we constructed TF-gene network and miRNA-TF-mRNA network based on data obtained from mRNA and miRNA expression profiles for analysis of HCC. We found that 42 key genes from the TF-gene network including EGR1, FOS, and FOSB were most enriched in the p53 signaling pathway. The qRT-PCR data confirmed that mRNA levels of EGR1, FOS, and FOSB all were decreased in HCC tissues. In addition, we confirmed that the mRNA levels of CCNB1, CCNB2, and CHEK1, three key markers of the p53 signaling pathway, were all increased in HCC tissues by bioinformatics analysis and qRT-PCR validation. Therefore, we speculated that miR-181a-5p, which was upregulated in HCC tissues, could regulate FOS and EGR1 to promote the invasion and progression of HCC by p53 signaling pathway. Overall, the study provides support for the possible mechanisms of progression in HCC.

HBX protein promotes LASP-1 expression through activation of c-Jun in human hepatoma cells

LIM and SH3 domain protein 1 (LASP-1) is known to participate in the progression of hepatocellular carcinoma (HCC). We previously showed that ectopic expression of hepatitis B virus (HBV) X protein (HBX) enhanced the expression of LASP-1, which promoted proliferation and migration of HCC cells. Here, we further demonstrated the molecular mechanism underlying upregulation of LASP-1, mediated by HBX, in HBV-infected HCC cells. Through a luciferase activity assay, we discovered that the LASP-1 promoter region regulated by HBX contained an AP-1 binding element in human hepatoma cells. Interestingly, c-Jun, one subunit of AP-1, was mainly responsible for activation, mediated by HBX, of the LASP-1 promoter. Furthermore, HBX was shown not only to interact with phosphorylated c-Jun in HCC cells but also to activate c-Jun by increasing the activation of PI3-K/JNK signaling. Chromatin immunoprecipitation (ChIP) assay demonstrated that HBX was capable of binding to the LASP-1 promoter with c-Jun. Further, the expression levels of HBX were shown to be significantly positively correlated with that of LASP-1 and phosphorylatedc-Jun in HBV-related HCC tissues by immunohistochemistry analysis. In addition, the N-terminus of HBX was found to be responsible for the activation of c-Jun, as well as the expression of LASP-1. Taken together, these results suggest that HBX contributes to LASP-1 expression via the activation of c-Jun to increase the promoter activity of LASP-1 in HBV-related HCC cells.

COPS5 and LASP1 synergistically interact to downregulate 14-3-3σ expression and promote colorectal cancer progression via activating PI3K/AKT pathway

Overexpression of LIM and SH3 protein 1 (LASP1) is required for colorectal cancer (CRC) development and progression. Here, C-Jun activation domain-binding protein-1 (Jab1), also known as COP9 signalosome subunit 5 (COPS5), was verified as a new LASP1-interacting protein through yeast two-hybrid assay. The role of COPS5 in LASP1-mediated CRC progression remains unknown. GST pull-down assay indicated that the SH3 domain of LASP1 could directly bind to MPN domain of COPS5. In vitro gain- and loss-of-function analyses revealed the stimulatory role of COPS5 on CRC cell proliferation, migration and invasion. Endogenous overexpression of COPS5 could also enhance the homing capacity of CRC cells in vivo. Further analysis showed that COPS5 and LASP1 synergistically interact to stimulate the ubiquitination and degradation of 14-3-3σ and promote colorectal cancer progression via PI3K/Akt dependent signaling pathway. Clinically, the expression of COPS5 was studied in CRC tissues and it is associated with CRC differentiation, metastasis and poor prognosis. The colocalization of LASP1 and COPS5 was demonstrated in both nonmetastatic and metastatic CRC tissues. A positive correlation was found between the expression of LASP1 and COPS5 while a negative correlation existed between 14-3-3σ and COPS5/LASP1 in most CRC samples. A combination of COPS5 and LASP1 tends to be an independent prognostic indicator for CRC patients, and this is also suitable for CRC without lymph node metastasis. The current research has further advanced our understanding on the complicated molecular mechanism underlying LASP1-mediated CRC progression, which hopefully will contribute to the development of novel diagnostic and therapeutic strategies in CRC.