Aberrant KLK4 gene promoter hypomethylation in pediatric hepatoblastomas

DNA methylation in Hepatoblastoma-a literature review

Hepatoblastoma (HB) is the most common malignant liver tumor in children. Abnormal activation of the Wnt/β-catenin signaling pathway plays an important role in the formation and development of HB. Genes in HB show a global hypomethylation change, accompanied by hypermethylation of specific tumor suppressor genes (TSGs). This article reviews the hypermethylation changes in several TSGs, such as RASSF1A, SOCS1, APC, HHIP, and P16, and analyzes the pathways and mechanisms of TSGs regulating gene expression. The role of the methylation-regulating enzymes DNA methyltransferases (DNMTs) and ten-eleven translocation (TET) family members enzymes in the methylation changes of HB was analyzed, and it was speculated that the occurrence of HB is partly due to the obstruction of liver differentiation in the early stage of differentiation. The origin cells may be incompletely differentiated hepatocytes remaining in the liver of children after birth. Therefore, further studying the role of methylation regulating enzymes in methylation changes in HB is a promising future research direction.

Hypermethylation of CSF3R is a novel cisplatin resistance marker and predictor of response to postoperative chemotherapy in hepatoblastoma

AIM

Most hepatoblastoma patients undergo pre/postoperative cisplatin treatment. Approximately 20% patients are cisplatin resistant, and show poor prognosis and high recurrence rates. However, some cisplatin-sensitive patients show early recurrence. We consider that a small population of cisplatin-resistant cells may remain after preoperative chemotherapy. Previous studies showed a correlation between DNA hypermethylation and hepatoblastoma progression. Here, we examined whether DNA hypermethylation was related to cisplatin resistance and could be a potential indicator for cisplatin as postoperative chemotherapy.

METHODS

We extracted DNA from 43 resected hepatoblastoma tumors. Methylation array analyses were performed in 11 samples, including six cisplatin-sensitive and five cisplatin-resistant samples. We also performed cDNA microarray analysis in parental and cisplatin-resistant HuH6 cells. Through comparison of the datasets, we selected the strongest correlated cisplatin-resistant candidate gene. Using bisulfite pyrosequencing, the candidate gene methylation level was assessed in 38 cisplatin-sensitive patients after checking its usefulness as a substitute modality of methylation array. Correlations between the methylation status and clinical data were analyzed.

RESULTS

CSF3R was the strongest correlated variable. Bisulfite pyrosequencing analysis also confirmed CSF3R was significantly hypermethylated in cisplatin-resistant patients. Among the 38 cisplatin-sensitive patients, recurrence curves showed that the CSF3R high methylation patients had significantly higher recurrence than CSF3R low methylation patients. The recurrence curve of methylation high patients was similar to that of cisplatin-resistant patients.

CONCLUSIONS

Our findings suggested that CSF3R hypermethylation was related to cisplatin resistance in HB patients and could be a predictor of postoperative chemotherapy, and indicate that CSF3R high methylation patients should be treated with non-CDDP regimens.

Association of CMYC polymorphisms with hepatoblastoma risk

BACKGROUND

Single-nucleotide polymorphisms (SNPs) in genes may affect gene expression and contribute to cancer susceptibility. This study aimed to explore the association between CMYC gene polymorphisms and hepatoblastoma risk.

METHODS

Hepatoblastoma patients and cancer-free controls were recruited and matched by age and sex. Genotypes were determined by TaqMan, and the strength of the association of interest was determined by calculating odds ratios (ORs) and 95% confidence intervals (CIs). The distributions of various CMYC genotypes among subjects were recorded, followed by analyses of associations between CMYC polymorphisms and hepatoblastoma risk.

RESULTS

A total of 213 hepatoblastoma patients and 958 cancer-free controls were enrolled. No significant associations between the CMYC rs4645943 and rs2070583 polymorphisms and hepatoblastoma risk were found (all P>0.05). In stratification analysis based on age, sex, and clinical stage, the CMYC rs4645943 and rs2070583 polymorphisms were not associated with hepatoblastoma susceptibility (all P>0.05).

CONCLUSIONS

Thus, the CMYC rs4645943 and rs2070583 polymorphisms were not associated with hepatoblastoma risk in the study cohort.

Demethylation-mediated upregulation of melanoma-associated antigen-A11 correlates with malignant progression of esophageal squamous cell carcinoma

BACKGROUND

The expression and methylation status of oncogenes are closely related to the onset and progression of cancer.

AIMS

To explore the role and methylation status of melanoma-associated antigen-A11 in the pathogenesis of esophageal squamous cell carcinoma.

METHODS

116 esophageal squamous cell carcinoma patients with tumor tissues and corresponding adjacent normal tissues were obtained. The expression level and methylation status of melanoma-associated antigen-A11 in esophageal cancer cell lines and esophageal squamous cell carcinoma tissues were determined respectively.

RESULTS

Significant up-regulation of melanoma-associated antigen-A11 was detected in esophageal cancer cell lines and esophageal squamous cell carcinoma tissues. Up-regulation of melanoma-associated antigen-A11 contributed to proliferation and invasion in cancer cells. Hypomethylation of the CpG site was associated with pathological differentiation, clinical stage, tumor size, lymph node metastasis and distant metastasis. Esophageal squamous cell carcinoma patients in stage III and IV, with high expression of melanoma-associated antigen-A11 or hypomethylation of the CpG site within the promoter demonstrated poor survival.

CONCLUSION

Melanoma-associated antigen-A11 is up-regulated in esophageal squamous cell carcinoma at least partly by hypomethylation of the CpG site within the promoter and this hypomethylation may affect the prognosis of esophageal squamous cell carcinoma patients.

Mass spectrometry based proteomics analyses in kallikrein-related peptidase research: implications for cancer research and therapy

INTRODUCTION

Kallikrein-related peptidases (KLKs) are a family of serine peptidases that are deregulated in numerous pathological conditions, with a multitude of KLK-mediated functional roles implicated in the progression of cancer. Advances in multidimensional mass spectrometry (MS)-based proteomics have facilitated the quantitative measurement of deregulated KLK expression in cancer, identifying certain KLKs, as well as their substrates, as potential cancer biomarkers. Areas covered: In this review, we discuss how these approaches have been utilized for KLK biomarker discovery and unbiased substrate determination in complex protein pools that mimic the in vivo extracellular microenvironment. Expert commentary: Although a limited number of studies have been performed, the quantity of information generated has greatly improved our understanding of the functional roles of KLKs in cancer progression. In addition, these data suggest additional means through which deregulated KLK expression may be targeted in cancer treatment, highlighting the potential therapeutic value of these state-of-the-art MS-based studies.