shRNA knockdown of DNA helicase ERCC6L expression inhibits human breast cancer growth

PLK-1 Interacting Checkpoint Helicase, PICH, Mediates Cellular Oxidative Stress Response

Cells respond to oxidative stress by elevating the levels of antioxidants, signaling, and transcriptional regulation, often implemented by chromatin remodeling proteins. The study presented here shows that the expression of PICH, a Rad54-like helicase belonging to the ATP-dependent chromatin remodeling protein family, is upregulated during oxidative stress in HeLa cells. We also show that PICH regulates the expression of Nrf2, a transcription factor regulating antioxidant response in both the absence and presence of oxidative stress. The overexpression of PICH in PICH-depleted cells restored Nrf2 as well as antioxidant gene expression. In turn, Nrf2 regulated the expression of PICH in the presence of oxidative stress. ChIP experiments showed that PICH is present on the Nrf2 as well as antioxidant gene promoters, suggesting that the protein might be regulating the expression of these genes directly by binding to the DNA sequences. In addition, Nrf2 and histone acetylation (H3K27ac) also played a role in activating transcription in the presence of oxidative stress. Both Nrf2 and H3K27ac were found to be present on PICH and antioxidant promoters. Their occupancy was dependent on the PICH expression as fold enrichment was found to be decreased in PICH-depleted cells. PICH ablation led to the reduced expression of Nrf2 and impaired antioxidant response, leading to increased ROS content and thus showing PICH is essential for the cell to respond to oxidative stress.

Eight hub genes as potential biomarkers for breast cancer diagnosis and prognosis: A TCGA-based study

BACKGROUND

Breast cancer (BC) is the most common malignant tumor in women.

AIM

To investigate BC-associated hub genes to obtain a better understanding of BC tumorigenesis.

METHODS

In total, 1203 BC samples were downloaded from The Cancer Genome Atlas database, which included 113 normal samples and 1090 tumor samples. The limma package of R software was used to analyze the differentially expressed genes (DEGs) in tumor tissues compared with normal tissues. The cluster Profiler package was used to perform Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis of upregulated and downregulated genes. Univariate Cox regression was conducted to explore the DEGs with statistical significance. Protein-protein interaction (PPI) network analysis was employed to investigate the hub genes using the CytoHubba plug-in of Cytoscape software. Survival analyses of the hub genes were carried out using the Kaplan-Meier method. The expression level of these hub genes was validated in the Gene Expression Profiling Interactive Analysis database and Human Protein Atlas database.

RESULTS

A total of 1317 DEGs (fold change > 2; P < 0.01) were confirmed through bioinformatics analysis, which included 744 upregulated and 573 downregulated genes in BC samples. KEGG enrichment analysis indicated that the upregulated genes were mainly enriched in the cytokine-cytokine receptor interaction, cell cycle, and the p53 signaling pathway (P < 0.01); and the downregulated genes were mainly enriched in the cytokine-cytokine receptor interaction, peroxisome proliferator-activated receptor signaling pathway, and AMP-activated protein kinase signaling pathway (P < 0.01).

CONCLUSION

In view of the results of PPI analysis, which were verified by survival and expression analyses, we conclude that MAD2L1, PLK1, SAA1, CCNB1, SHCBP1, KIF4A, ANLN, and ERCC6L may act as biomarkers for the diagnosis and prognosis in BC patients.

Upregulation of Excision Repair Cross-Complementation Group 6-Like (ERCC6L) Promotes Tumor Growth in Hepatocellular Carcinoma

BACKGROUND

Excision repair cross-complementation group 6-like (ERCC6L) is overexpressed in some malignancies; however, its role in hepatocellular carcinoma (HCC) remains to be further investigated.

AIMS

In the present study, we explored the expression and function of ERCC6L in HCC.

METHODS AND RESULTS

We investigated the expression of ERCC6L by microarray analysis, using the Cancer Genome Atlas database, and by HCC tissue microarray. The results showed that ERCC6L expression was upregulated in tumor specimens and HCC cell lines. High ERCC6L expression in tumor tissues was significantly correlated with poor prognosis and could serve as an independent prognostic indicator for HCC patients. Results of in vitro and in vivo assays revealed that ERCC6L substantially promoted cell proliferation, and our flow cytometry analysis revealed that this was accomplished by acceleration of the G1/S transition. Finally, gene set enrichment analysis and western blotting results indicated that ERCC6L might regulate HCC proliferation by activating p53 signaling.

CONCLUSIONS

Our study suggests that ERCC6L plays an important role in HCC proliferation and that it might serve as a promising therapeutic target in HCC.

Adipose most abundant 2 protein is a predictive marker for cisplatin sensitivity in cancers

Cisplatin (CDDP) is one of the chemotherapeutic drugs being used to treat various cancers. Although effective in many cases, as high doses of CDDP cause cytotoxic effects that may worsen patients' condition, therefore, a marker of sensitivity to CDDP is necessary to enhance the safety and efficiency of CDDP administration. This study focused on adipose most abundant 2 (APM2) to examine its potential as a marker of CDDP sensitivity. The relationship of APM2 expression with the mechanisms of CDDP resistance was examined in vitro and in vivo using hepatocellular carcinoma (HCC) cells, tissues and serum of HCC patients (n = 71) treated initially with intrahepatic arterial infusion of CDDP followed by surgical resection. The predictability of serum APM2 for CDDP sensitivity was assessed in additional 54 HCC patients and 14 gastric cancer (GC) patients. APM2 expression in CDDP-resistant HCC was significantly higher both in serum and the tissue. Bioinformatic analyses and histological analyses demonstrated upregulation of ERCC6L (DNA excision repair protein ERCC6-like) by APM2, which accounts for the degree of APM2 expression. The serum APM2 level and chemosensitivity for CDDP were assessed and cut-off value of serum APM2 for predicting the sensitivity to CDDP was determined to be 18.7 µg/mL. The value was assessed in HCC (n = 54) and GC (n = 14) patients for its predictability of CDDP sensitivity, resulted in predictive value of 77.3% and 100%, respectively. Our study demonstrated that APM2 expression is related to CDDP sensitivity and serum APM2 can be an effective biomarker of HCC and GC for determining the sensitivity to CDDP.Trial registration: This study was registered with the University Hospital Medical Information Network Clinical Trials Registry (UMIN000028487).

Upregulation of ERCC6L is associated with tumor progression and unfavorable prognosis in hepatocellular carcinoma

Background

The oncogenic role of excision repair cross-complementation group 6-like (ERCC6L) has been revealed in several cancers recently, but little is known about its expression and function in hepatocellular carcinoma (HCC).

Methods

Utilizing public data from Human Protein Atlas (HPA) and The Cancer Genome Atlas (TCGA) databases, ERCC6L dysregulation in HCC and its clinical significance were determined by t-test and Chi-square test. Comprehensive survival analyses (such as nomogram, Cox regression model and Kaplan-Meier analysis) were performed to assess prognostic value of ERCC6L for HCC patients. Integrated bioinformatics analyses [including copy number alterations (CNA), DNA methylation, miRNA prediction and gene set enrichment analysis (GSEA)] were conducted to explore the mechanisms and biological roles underlying ERCC6L dysregulation in HCC.

Results

ERCC6L upregulation was identified in HCC tissues compared to normal controls (P<0.05). In addition, overexpression of ERCC6L not only correlated with elevated alpha fetoprotein (AFP), vascular invasion (VI), and advanced histologic grade and TNM stage, but also had an independent prognostic value for the poorer overall survival (OS) and recurrence-free survival (RFS) of HCC patients (all P<0.05). Besides, nomogram integrating ERCC6L expression and TNM stage showed superior prognostic ability than that of TNM stage (P<0.05). Moreover, ERCC6L promoter hypomethylation and miR-5589 downregulation in HCC might result in ERCC6L overexpression (all P<0.05). Furthermore, eight biological pathways (including the DNA replication, cell cycle and p53 pathways) related to ERCC6L upregulation in HCC were found to be enriched by GSEA, and ERCC6L upregulation was positively correlated with PLK1 (polo-like kinase 1) expression and TP53 mutation in HCC, which preliminarily shed light on the roles of ERCC6L in HCC.

Conclusions

ERCC6L may serve as a promising prognostic indicator and therapeutic target for HCC patients.

ERCC6L promotes the progression of hepatocellular carcinoma through activating PI3K/AKT and NF-κB signaling pathway

Background

Excision Repair Cross-Complementation group 6-like (ERCC6L) has been shown to exhibit carcinogenic effect in several malignant tumors. However, the function and molecular mechanism of the ERCC6L in hepatocellular carcinoma (HCC) have not been investigated extensively.

Methods

Immunohistochemistry analyses were used to detect ERCC6L expression in a HCC tissue microarray, and the Chi-square test was used to assess the correlation between ERCC6L expression and patients’ clinicopathological features. shRNA was used to down-regulation ERCC6L expression in HCC cell lines. MTT assay, plate clone formation assay, flow cytometry, caspase 3/7 activity and migration assays were performed to evaluate the impact of ERCC6L on HCC cells in vitro. Nude mice xenograft models were used to assess the role of ERCC6L in vivo. The regulatory of mechanism of PI3K/AKT pathway was evaluated by western blotting.

Results

ERCC6L was highly expressed in HCC tissue compared with tumor adjacent tissues in 90 paired samples. ERCC6L expression positively correlated with gender, tumor encapsulation, and pathological stage. Patients with low ERCC6L expression had significantly longer OS than those with high ERCC6L expression. Knockdown of ERCC6L expression significantly inhibited proliferation, invasion and metastasis in vitro and tumor growth in vivo, and it promoted cell cycle arrest and apoptosis. Mechanistic analyses revealed that PI3K/AKT and NF-κB signaling pathway were inhibited by silencing ERCC6L.

Conclusion

These results demonstrate that ERCC6L plays a critical role in HCC progression, and thereby might be a potential therapeutic target for HCC patients.