Predicting prognosis in hepatocellular carcinoma after curative surgery with common clinicopathologic parameters

Two-tiered approach identifies a network of cancer and liver disease-related genes regulated by miR-122

MicroRNAs function as important regulators of gene expression and are commonly linked to development, differentiation, and diseases such as cancer. To better understand their roles in various biological processes, identification of genes targeted by microRNAs is necessary. Although prediction tools have significantly helped with this task, experimental approaches are ultimately required for extensive target search and validation. We employed two independent yet complementary high throughput approaches to map a large set of mRNAs regulated by miR-122, a liver-specific microRNA implicated in regulation of fatty acid and cholesterol metabolism, hepatitis C infection, and hepatocellular carcinoma. The combination of luciferase reporter-based screening and shotgun proteomics resulted in the identification of 260 proteins significantly down-regulated in response to miR-122 in at least one method, 113 of which contain predicted miR-122 target sites. These proteins are enriched for functions associated with the cell cycle, differentiation, proliferation, and apoptosis. Among these miR-122-sensitive proteins, we identified a large group with strong connections to liver metabolism, diseases, and hepatocellular carcinoma. Additional analyses, including examination of consensus binding motifs for both miR-122 and target sequences, provide further insight into miR-122 function.

Global regulation on microRNA in hepatitis B virus-associated hepatocellular carcinoma

Recent work has revealed the causative links between deregulation of microRNAs (miRNAs) and cancer development. In hepatocellular carcinoma (HCC), aberrant expression of miRNAs has been observed, but the molecular mechanisms that contribute to such changes remains to be elucidated. Here, we reported the analysis of miRNA expression in 94 pairs of tumor and adjacent nontumor tissues from HBV-associated HCC in Chinese patients. We found miRNAs were aberrantly expressed in HCC tissues. To investigate the cause of such deregulation, we detected changes in DNA copy number by measuring locus-specific hybridization intensity, and found changes in expression of several miRNAs are correlated with genomic amplification or deletion. For example, the genomic regions of miR-30d and miR-151 were amplified in ∼50% of HCC tumor tissues, and the expressions of these miRNAs are significantly correlated with DNA copy number. We also employed cDNA microarray data, and provide evidence that key regulators of the miRNA biosynthetic pathway, including DROSHA, DGCR8, AGO1, and AGO2, are frequently overexpressed in HCC. This study provides molecular clues that may contribute to the global changes of miRNA expression in HCC.

HNF1α and CDX2 transcriptional factors bind to cadherin-17 (CDH17) gene promoter and modulate its expression in hepatocellular carcinoma

Cadherin-17 (CDH17) belongs to the cell adhesion cadherin family with a prominent role in tumorigenesis. It is highly expressed in human hepatocellular carcinoma (HCC) and is proposed to be a biomarker and therapeutic molecule for liver malignancy. The present study aims to identify the transcription factors which interact and regulate CDH17 promoter activity that might contribute to the up-regulation of CDH17 gene in human HCC. A 1-kb upstream sequence of CDH17 gene was cloned and the promoter activity was studied by luciferase reporter assay. By bioinformatics analysis, deletion and mutation assays, and chromatin immunoprecipitation studies, we identified hepatic nuclear factor 1α (HNF1α) and caudal-related homeobox 2 (CDX2) binding sites at the proximal promoter region which modulate the CDH17 promoter activities in two HCC cell lines (Hep3B and MHCC97L). A consistent down-regulation of CDH17 and the two transcriptional activators (HNF1α and CDX2) expression was found in the liver of mouse during development, as well as in human liver cancer cells with less metastatic potential. Suppression of HNF1α and CDX2 expression by small interfering RNA (siRNA) significantly down-regulated expressions of CDH17 and its downstream target cyclin D1 and the viability of HCC cells in vitro. In summary, we identified the minimal promoter region of CDH17 that is regulated by HNF1α and CDX2 transcriptional factors. The present findings enhance our understanding on the regulatory mechanisms of CDH17 oncogene in HCC, and may shed new insights into targeting CDH17 expression as potential therapeutic intervention for cancer treatment.

Genetic polymorphism of CCR2-64I increased the susceptibility of hepatocellular carcinoma

BACKGROUND AND OBJECTIVES

The purpose of this study was to investigate genetic impact of monocyte chemoattractant protein-1 (MCP-1) and its receptor chemokine receptor-2 (CCR2) gene polymorphisms on the susceptibility and clinicopathological characteristics of hepatocellular carcinoma (HCC).

METHODS

A total of 446 subjects, including 344 healthy controls and 102 patients with HCC, were recruited in this study and subjected to PCR-RFLP to estimate the impact of these two polymorphic variants on HCC.

RESULTS

No relationship between MCP-1 -2518G/A gene polymorphism and HCC risk was found among our recruited HCC patients and healthy controls. However, there was a significantly increased risk (AOR = 1.91; 95% CI = 1.11-3.29) of having HCC among subjects with GA heterozygotes of CCR2 V64I after adjusting for other confoundings. There was no synergistic effect between gene polymorphism and environmental risk factors, including tobacco and alcohol consumptions, as well as clinicopathological parameters of HCC for MCP-1 -2518G/A and CCR2 V64I genes, respectively.

CONCLUSIONS

CCR2-64I gene polymorphism is an important factor for the susceptibility of HCC but it might not influence the clinical pathological progression of HCC, and the contribution of CCR2-64I gene polymorphism on the susceptibility of HCC could be not through the affection of liver injury-related clinical pathological characteristics.

Proteomics of hepatocellular carcinoma: serum vimentin as a surrogate marker for small tumors (<or=2 cm)

Small hepatocellular carcinomas (HCCs) can be effectively cured by surgery with good clinical outcomes. However, the conventional AFP marker is ineffective in detecting small tumors. Here we employed a proteomic profiling approach to identify a candidate marker for HCC (<or=2 cm) in tumor tissues and then evaluate its clinical feasibility in patients' sera. The study was divided into 2 phases. (i) Biomarker discovery: we collected 76 frozen liver tissues (40 HCC and 36 controls) for proteomics profiling. Candidate protein markers were identified by MALDI-TOF/TOF and confirmed by immunoblot and qPCR. (ii) Clinical evaluation: Selected biomarker was tested by ELISA for sensitivity and specificity using serum samples from a separate cohort of 152 subjects (88 HCC and 64 controls). Vimentin was found significantly overexpressed in HCC, in particular the small-size subgroup (<or=2 cm) with p < 0.01. When tested in the serum samples, vimentin level was significantly higher in small tumors than the non-neoplastic controls (AUC = 0.69 and p < 0.01). Further analysis suggested that elevated circulating vimentin level could detect small HCC at 40.91% sensitivity and 87.50% specificity. Moreover, vimentin was found to be superior to serum AFP assayed at different cut-offs in detecting small tumors. When combined with AFP, the detection sensitivity and specificity could be further enhanced to 58.77 and 98.15%, respectively. In conclusion, serum vimentin is a potential surrogate marker, either alone or in combination with AFP, for detection of small HCCs.

Enhanced detection of early hepatocellular carcinoma by serum SELDI-TOF proteomic signature combined with alpha-fetoprotein marker

Background

Biomarkers for accurate diagnosis of early hepatocellular carcinoma (HCC) are limited in number and clinical validation. We applied SELDI-TOF-MS ProteinChip technology to identify serum profile for distinguishing HCC and liver cirrhosis (LC) and to compare the accuracy of SELDI-TOF-MS profile and alpha-fetoprotein (AFP) level in HCC diagnosis.

Patients and Methods

Serum samples were obtained from 120 HCC and 120 LC patients for biomarker discovery and validation studies. ProteinChip technology was employed for generating SELDI-TOF proteomic features and analyzing serum proteins/peptides.

Results

A diagnostic model was established by CART algorithm, which is based on 5 proteomic peaks with m/z values at 3324, 3994, 4665, 4795, and 5152. In the training set, the CART algorithm could differentiate HCC from LC subjects with a sensitivity and specificity of 98% and 95%, respectively. The results were assessed in blind validation using separate cohorts of 60 HCC and 60 LC patients, with an accuracy of 83% for HCC and 92% for LC patients. The diagnostic odd ratio (DOR) indicated that SELDI-TOF proteomic signature could achieve better diagnostic performance than serum AFP level at a cutoff of 20 ng/mL (AFP₂₀) (92.72 vs 9.11), particularly superior for early-stage HCC (87% vs 54%). Importantly, a combined use of both tests could enhance the detection of HCC (sensitivity, 95%; specificity, 98%; DOR, 931).

Conclusion

Serum SELDI-TOF proteomic signature, alone or in combination with AFP marker, promises to be a good tool for early diagnosis and/screening of HCC in at-risk population with liver cirrhosis.

MicroRNA-375 targets Hippo-signaling effector YAP in liver cancer and inhibits tumor properties

Hepatocellular carcinoma (HCC) is a malignant form of liver cancer that ranks the second leading cause of cancer-related deaths in China and many Asia regions. The dismal outcome reflects the need for a better understanding of the transcriptional control of oncogenic signaling pathway. Our recent findings have identified yes-associated protein (YAP) is a potent oncogenic driver and independent prognostic risk factor of HCC. The present study aims to elucidate the transcriptional regulation of YAP targeted by microRNA (miRNA). miR-375 is a putative target and was found significantly down-regulated in the tumor versus adjacent non-tumor tissues of HCC patients (n=48). As determined by luciferase reporter assay, we found ectopic expression of miR-375 could diminish the transcriptional activity of YAP. Furthermore, immunoblotting revealed miR-375 suppressed endogenous YAP protein level. Functional assays showed that miR-375 was able to inhibit proliferation and invasion of HCC cells.

CONCLUSION

miR-375 is an important regulator of YAP oncogene, implicating a potential therapeutic role in HCC treatment.