Proteomics for the early detection and treatment of hepatocellular carcinoma

Dysregulation of miR-3607 predicts prognosis of hepatocellular carcinoma and regulates tumor cell proliferation, migration and invasion

Background

Hepatocellular carcinoma (HCC) is one of the most common global malignancies with increasing morbidity and mortality. The purpose of this study was to investigate the expression levels and prognostic value of microRNA-3607 (miR-3607) in patients with HCC.

Methods

The expression of miR-3607 was estimated by quantitative real-time RT-PCR. Survival analysis using the Kaplan-Meier method and Cox regression analysis was conducted to evaluate the prognostic value of miR-3607. The functional role of miR-3607 in HCC progression was further assessed using gain- and loss-of-function experiments. Bioinformatics analysis and a dual-luciferase reporter assay were used to explore the direct targets of miR-3607.

Results

miR-3607 expression was found to be significantly decreased in HCC tissues and cells compared with the matched tissues and cells (P < 0.001). The decreased expression of miR-3607 was associated with the patients’ tumor size and TNM stage (all P < 0.05). According to the survival curves, patients with low miR-3607 expression had poorer overall survival than those with high levels (log-rank P = 0.012). Moreover, the Cox analysis results indicated that miR-3607 expression was an independent prognostic factor for HCC. The results of cell experiments revealed that the overexpression of miR-3607 in HCC cells led to the inhibited cell proliferation, migration, and invasion. TGFBR1 was identified as a direct target of miR-3607.

Conclusion

The data of this study indicated that the decreased expression of miR-3607 in HCC predicts poor prognosis and the overexpression of miR-3607 in HCC cells can suppress the tumor progression by targeting TGFBR1. This study provides a novel insight into the prognosis and treatment of HCC, and miR-3607 serves as a candidate prognostic biomarker and therapeutic target of HCC.

Application of Proteomics to Inflammatory Bowel Disease Research: Current Status and Future Perspectives

Inflammatory bowel disease (IBD) is a chronic relapsing/remitting inflammatory illness of the gastrointestinal tract of unknown aetiology. Despite recent advances in decoding the pathophysiology of IBD, many questions regarding disease pathogenesis remain. Genome-wide association studies (GWAS) and knockout mouse models have significantly advanced our understanding of genetic susceptibility loci and inflammatory pathways involved in IBD pathogenesis. Despite their important contribution to a better delineation of the disease process in IBD, these genetic findings have had little clinical impact to date. This is because the presence of a given gene mutation does not automatically correspond to changes in its expression or final metabolic or structural effect(s). Furthermore, the existence of these gene susceptibility loci in the normal population suggests other driving prerequisites for the disease manifestation. Proteins can be considered the main functional units as almost all intracellular physiological functions as well as intercellular interactions are dependent on them. Proteomics provides methods for the large-scale study of the proteins encoded by the genome of an organism or a cell, to directly investigate the proteins and pathways involved. Understanding the proteome composition and alterations yields insights into IBD pathogenesis as well as identifying potential biomarkers of disease activity, mucosal healing, and cancer progression. This review describes the state of the art in the field with respect to the study of IBD and the potential for translation from biomarker discovery to clinical application.

Long noncoding RNA PCAT-14 induces proliferation and invasion by hepatocellular carcinoma cells by inducing methylation of miR-372

Long non-coding RNAs (lncRNAs) regulate oncogenesis by inducing methylation of CpG islands to silence target genes. Here we show that the lncRNA PCAT-14 is overexpressed in patients with hepatocellular carcinoma (HCC), and is associated with a poor prognosis after surgery. Our results demonstrate that PCAT-14 promotes proliferation, invasion, and cell cycle arrest in HCC cells. In addition, PCAT-14 inhibits miR-372 expression by inducing methylation of the miR-372 promoter. Simultaneously, miR-372 eliminates the effects of PCAT-14 on proliferation, invasion, and cell cycle in HCC cells. Moreover, PCAT-14 regulates expression of ATAD2 and activation of the Hedgehog pathway via miR-372. These findings indicate that PCAT-14 plays an important role in HCC, and may serve as a novel prognostic factor and therapeutic target.

Huntington's Disease and Mitochondria

Huntington's disease (HD) as an inherited neurodegenerative disorder leads to neuronal loss in striatum. Progressive motor dysfunction, cognitive decline, and psychiatric disturbance are the main clinical symptoms of the HD. This disease is caused by expansion of the CAG repeats in exon 1 of the huntingtin which encodes Huntingtin protein (Htt). Various cellular and molecular events play role in the pathology of HD. Mitochondria as important organelles play crucial roles in the most of neurodegenerative disorders like HD. Critical roles of the mitochondria in neurons are ATP generation, Ca²⁺ buffering, ROS generation, and antioxidant activity. Neurons as high-demand energy cells closely related to function, maintenance, and dynamic of mitochondria. In the most neurological disorders, mitochondrial activities and dynamic are disrupted which associate with high ROS level, low ATP generation, and apoptosis. Accumulation of mutant huntingtin (mHtt) during this disease may evoke mitochondrial dysfunction. Here, we review recent findings to support this hypothesis that mHtt could cause mitochondrial defects. In addition, by focusing normal huntingtin functions in neurons, we purpose mitochondria and Huntingtin association in normal condition. Moreover, mHtt affects various cellular signaling which ends up to mitochondrial biogenesis. So, it could be a potential candidate to decline ATP level in HD. We conclude how mitochondrial biogenesis plays a central role in the neuronal survival and activity and how mHtt affects mitochondrial trafficking, maintenance, integrity, function, dynamics, and hemostasis and makes neurons vulnerable to degeneration in HD.

The transcription factor p53: not a repressor, solely an activator

The predominant function of the tumor suppressor p53 is transcriptional regulation. It is generally accepted that p53-dependent transcriptional activation occurs by binding to a specific recognition site in promoters of target genes. Additionally, several models for p53-dependent transcriptional repression have been postulated. Here, we evaluate these models based on a computational meta-analysis of genome-wide data. Surprisingly, several major models of p53-dependent gene regulation are implausible. Meta-analysis of large-scale data is unable to confirm reports on directly repressed p53 target genes and falsifies models of direct repression. This notion is supported by experimental re-analysis of representative genes reported as directly repressed by p53. Therefore, p53 is not a direct repressor of transcription, but solely activates its target genes. Moreover, models based on interference of p53 with activating transcription factors as well as models based on the function of ncRNAs are also not supported by the meta-analysis. As an alternative to models of direct repression, the meta-analysis leads to the conclusion that p53 represses transcription indirectly by activation of the p53-p21-DREAM/RB pathway.

Low mir-372 expression correlates with poor prognosis and tumor metastasis in hepatocellular carcinoma

BACKGROUND

Recent studies have shown that miR-372 plays important roles in hepatocellular carcinoma (HCC) progression. However, results have been conflicting regarding its expression levels and role in HCC.

METHODS

RT-PCR and in situ hybridization was used to evaluate miR-372 expression in HCC tissues and cell lines. The methylation status of neighboring CpG islands upstream of the miR-372 promoter was analyzed by methylation-specific PCR (MSP). Transfection of miR-372 mimic into HCC cell lines was used to evaluate cellular proliferation and invasion. Prognostic significance was analyzed by the Kaplan-Meier survival method and Cox regression.

RESULTS

miR-372 was expressed at lower levels in HCC tissues compared with controls and was related to tumor metastasis and poor prognosis. Hypermethylation of miR-372 was detected in HCC cell lines and tissues, and miR-372 expression was restored upon 5-aza-dCyd treatment. Upregulated expression by mir-372 mimic transfection inhibited proliferation and invasion capacity in HCC cells.

CONCLUSIONS

miR-372 may play an important role in hepatic carcinogenesis and may serve as a new target or method to detect and treat HCC in the future.

Epigenetic high regulation of ATAD2 regulates the Hh pathway in human hepatocellular carcinoma

ATAD2 is associated with many cellular progresses such as cell growth, differentiation and apoptosis. Some studies suggest ATAD2 is highly expressed in cancer cells. In our previous studies, we found that ATAD2 is highly expressed in HCC tissues, compared with adjacent normal tissues, and patients with high expression of ATAD2 had a poorer prognosis. Moreover, we found mir-372 can regulate the expression of ATAD2 in HCC cell lines. We also detected a relationship between the mRNA expression of ATAD2 and Ptch1 by gene microarray. Here, we completed the function studies of ATAD2 in vivo and in vitro, and tested whether ATAD2 could regulate the Hh pathway. ATAD2 and Hh pathway protein expressions in 80 HCC specimens were examined by immunohistochemistry (IHC). The mRNA expression of ATAD2 and Hh pathway members in paired-HCC tissues and cell lines were, respectively, analyzed using quantitative PCR. ATAD2‑RNAi was transduced into HCCLM3 and Huh7 cells, using a lentiviral vector. The effect of ATAD2 in HCC cell lines on cell cycle and apoptosis were evaluated by flow cytometry. Tumorigenicity experiments in nude mice were performed to test the function of ATAD2 in vivo. Pharmacological regulation of Hh signaling was performed to test the relation between the ATAD2 and Hh pathways and C-myc. We found that ATAD2 and Ptch1 were both highly expressed in HCC tissues, compared with paired normal hepatic tissues. In addition, we found that ATAD2 could affect the expression of the Hh pathway by PCR and western blot anaysis in HCC cell lines, by observing the outcome before and after transfection. We speculate that ATAD2 cooperates with the MYC gene to regulate the expression of SMO and Gli, activating the Hh pathway and inducing an active feedback of the Hh pathway.

Biomarkers in inflammatory bowel diseases: Current status and proteomics identification strategies

Unambiguous diagnosis of the two main forms of inflammatory bowel diseases (IBD): Ulcerative colitis (UC) and Crohn’s disease (CD), represents a challenge in the early stages of the diseases. The diagnosis may be established several years after the debut of symptoms. Hence, protein biomarkers for early and accurate diagnostic could help clinicians improve treatment of the individual patients. Moreover, the biomarkers could aid physicians to predict disease courses and in this way, identify patients in need of intensive treatment. Patients with low risk of disease flares may avoid treatment with medications with the concomitant risk of adverse events. In addition, identification of disease and course specific biomarker profiles can be used to identify biological pathways involved in the disease development and treatment. Knowledge of disease mechanisms in general can lead to improved future development of preventive and treatment strategies. Thus, the clinical use of a panel of biomarkers represents a diagnostic and prognostic tool of potentially great value. The technological development in recent years within proteomic research (determination and quantification of the complete protein content) has made the discovery of novel biomarkers feasible. Several IBD-associated protein biomarkers are known, but none have been successfully implemented in daily use to distinguish CD and UC patients. The intestinal tissue remains an obvious place to search for novel biomarkers, which blood, urine or stool later can be screened for. When considering the protein complexity encountered in intestinal biopsy-samples and the recent development within the field of mass spectrometry driven quantitative proteomics, a more thorough and accurate biomarker discovery endeavor could today be performed than ever before. In this review, we report the current status of the proteomics IBD biomarkers and discuss various emerging proteomic strategies for identifying and characterizing novel biomarkers, as well as suggesting future targets for analysis.

Proteome Analyses of Hepatocellular Carcinoma

Proteomics has evolved into a powerful and widely used bioanalytical technique in the study of cancer, especially hepatocellular carcinoma (HCC). In this review, we provide an up to date overview of feasible proteome-analytical techniques for clinical questions. In addition, we present a broad summary of proteomic studies of HCC utilizing various technical approaches for the analysis of samples derived from diverse sources like HCC cell lines, animal models, human tissue and body fluids.

miR-372 down-regulates the oncogene ATAD2 to influence hepatocellular carcinoma proliferation and metastasis

Background

ATAD2 is associated with many cellular processes, such as cell growth, migration and invasion. However, no studies have been conducted on the molecular biological function of the ATAD2 gene in hepatocellular carcinoma (HCC).

Methods

The protein and mRNA level expression of ATAD2 was examined in tissues and cell lines. Prognostic significance was analyzed by the Kaplan-Meier survival method and Cox regression. ATAD2 knockdown was used to analyze cell proliferation and invasion. The upstream and downstream of ATAD2 was analyzed by RT² Profiler™ PCR array and luciferasex fluorescence system.

Results

ATAD2 was highly expressed in liver cancer samples and correlated with poor survival. High ATAD2 expression was positively correlated with metastasis (P = 0.005) and was an independent prognostic factor in HCC (P = 0.001). ATAD2 depletion by RNA interference reduced their capacity for invasion and proliferation and led to a G1 phase arrest in vitro. Further study revealed that miR-372 was an upstream target of ATAD2 as miR-372 was bound directly to its 3′ untranslated region (3′ UTR). In addition, ATAD2 knockdown was found to extremely up-regulate APC expression and down-regulate CTNNA1 at the mRNA level.

Conclusions

The findings demonstrated that miR-372 suppressed the expression of ATAD2, which was highly expressed in HCC and exerted a proto-oncogene effect in hepatic carcinogenesis. In conclusion, ATAD2 may promote HCC progression.

Increased concentrations of apo A-I and apo A-II fragments in the serum of patients with hepatocellular carcinoma by magnetic beads-assisted MALDI-TOF mass spectrometry

OBJECTIVES

Recent advances in sophisticated technologies in proteomics should provide promising ways to discover novel markers for hepatocellular carcinoma (HCC) in the early diagnosis.

METHODS

Serum peptide and protein profiling was conducted by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Profiling was carried out in a training set of 16 patients with HCC and a testing set of 15 patients with cirrhosis without HCC. All the patients were hepatitis C virus positive. Candidate peaks were processed to partial purification, followed by protein identification by amino acid sequence analysis. Immunoprecipitation was conducted to confirm the protein identity.

RESULTS

Partial purification and protein identification revealed that one peak that was up-regulated in HCC sera both in the training and the testing sets was a fragment of apolipoprotein A-I (apo A-I). Immunoprecipitation confirmed this result.

CONCLUSIONS

MALDI-TOF MS analysis revealed that apo A-I is a potential novel serum marker of HCC. Combination of these pretreatments and the current magnet bead-assisted MALDI-TOF MS will further enhance the efficiency of biomarker discovery for HCC.

Neurobiology of Huntington's Disease

Of the neurodegenerative diseases presented in this book, Huntington's disease (HD) stands as the archetypal autosomal dominantly inherited neurodegenerative disorder. Its occurrence through generations of affected families was noted long before the basic genetic underpinnings of hereditary diseases was understood. The early classification of HD as a distinct hereditary neurodegenerative disorder allowed the study of this disease to lead the way in the development of our understanding of the mechanisms of human genetic disorders. Following its clinical and pathologic characterization, the causative genetic mutation in HD was subsequently identified as a trinucleotide (CAG) repeat expansion in the huntingtin (HTT) gene, and consequently, the HTT gene and huntingtin protein have been studied in great detail. Despite this concentrated effort, there is still much about the function of huntingtin that still remains unknown. Presented in this chapter is an overview of the current knowledge on the normal function of huntingtin and some of the potential neurobiologic mechanisms by which the mutant HTT gene may mediate neurodegeneration in HD.

Identification of serum monocyte chemoattractant protein-1 and prolactin as potential tumor markers in hepatocellular carcinoma

Early diagnosis of hepatocellullar carcinoma (HCC) remains a challenge. The current practice of serum alpha-fetoprotein (AFP) measurement is inadequate. Here we utilized a proteomic approach to identify novel serum biomarkers for distinguishing HCC patients from non-cancer controls. We profiled the serum proteins in a group of 58 resectable HCC patients and 11 non-HCC chronic hepatitis B (HBV) carrier samples from the Singapore General Hospital (SGH) using the RayBio® L-Series 507 Antibody Array and found 113 serum markers that were significantly modulated between HCC and control groups. Selected potential biomarkers from this list were quantified using a multiplex sandwich enzyme-linked immunosorbent assay (ELISA) array in an expanded SGH cohort (126 resectable HCC patients and 115 non-HCC chronic HBV carriers (NC group)), confirming that serum prolactin and monocyte chemoattractant protein-1 (MCP-1) were significantly upregulated in HCC patients. This finding of serum MCP-1 elevation in HCC patients was validated in a separate cohort of serum samples from the Mochtar Riady Institute for Nanotechnology, Indonesia (98 resectable HCC, 101 chronic hepatitis B patients and 100 asymptomatic HBV/HCV carriers) by sandwich ELISA. MCP-1 and prolactin levels were found to correlate with AFP, while MCP-1 also correlated with disease stage. Subsequent receiver operating characteristic (ROC) analysis of AFP, prolactin and MCP-1 in the SGH cohort and comparing their area under the ROC curve (AUC) indicated that neither prolactin nor MCP-1 on their own performed better than AFP. However, the combination of AFP+MCP-1 (AUC, 0.974) had significantly superior discriminative ability than AFP alone (AUC, 0.942; p<0.001). In conclusion, prolactin and MCP-1 are overexpressed in HCC and are conveniently quantifiable in patients’ sera by ELISA. MCP-1 appears to be a promising complementary biomarker for HCC diagnosis and this MCP-1+AFP model should be further evaluated as potential biomarker on a larger scale in patients at-risk of HCC.

p53 mutations associated with aging-related rise in cancer incidence rates

TP53’s role as guardian of the genome diminishes with age, as the probability of mutation increases. Previous studies have shown an association between p53 gene mutations and cancer. However, the role of somatic TP53 mutations in the steep rise in cancer rates with aging has not been investigated at a population level. This relationship was quantified using the International Agency for Research on Cancer (IARC) TP53 and GLOBOCAN cancer databases. The power function exponent of the cancer rate was calculated for 5-y age-standardized incidence or mortality rates for up to 25 cancer sites occurring in adults of median age 42 to 72 y. Linear regression analysis of the mean percentage of a cancer’s TP53 mutations and the corresponding cancer exponent was conducted for four populations: worldwide, Japan, Western Europe, and the United States. Significant associations (P ≤ 0.05) were found for incidence rates but not mortality rates. Regardless of the population studied, positive associations were found for all cancer sites, with more significant associations for solid tumors, excluding the outlier prostate cancer or sex-related tumors. Worldwide and Japanese populations yielded P values as low as 0.002 and 0.005, respectively. For the United States, a significant association was apparent only when analysis utilized the Surveillance, Epidemiology, and End Results (SEER) database. This study found that TP53 mutations accounts for approximately one-quarter and one-third of the aging-related rise in the worldwide and Japanese incidence of all cancers, respectively. These significant associations between TP53 mutations and the rapid rise in cancer incidence with aging, considered with previously published literature, support a causal role for TP53 according to the Bradford-Hill criteria. However, questions remain concerning the contribution of TP53 mutations to neoplastic development and the role of factors such as genetic instability, obesity, and gene deficiencies other than TP53 that reduce p53 activity.

Low RIN1 expression in HCC is associated with tumor invasion and unfavorable prognosis

OBJECTIVES

To explore the association between the expression of Ras and Rab interactor 1 (RIN1) and the prognosis of hepatocellular carcinoma (HCC).

METHODS

RIN1 expression was detected in paired HCC tissues by real-time polymerase chain reaction, Western blot analysis, and immunohistochemistry. Transfection was applied to analyze the RIN1 function.

RESULTS

We found that expression of the RIN1 protein was downregulated in the HCC samples compared with the corresponding normal tissues. Downregulation of RIN1 expression was also associated with invasion and poor overall survival (OS). The results of our multivariate analysis indicated that the RIN1 status is a significant prognostic factor for OS. RIN1 overexpression also inhibited cell invasion in HepG2 cells. The expression between RIN1 and ABL2 may present a positive correlation.

CONCLUSIONS

Our results demonstrate that RIN1 suppresses tumor invasion in HCC patients and that a poor prognosis for HCC is expected when RIN1 expression is downregulated.

Alterations in the redox state and liver damage: hints from the EASL Basic School of Hepatology

The importance of a correct balance between oxidative and reductive events has been shown to have a paramount effect on cell function for quite a long time. However, in spite of this body of rapidly growing evidence, the implication of the alteration of the redox state in human disease has been so far much less appreciated. Liver diseases make no exception. Although not fully comprehensive, this article reports what discussed during an EASL Basic School held in 2012 in Trieste, Italy, where the effect of the alteration of the redox state was addressed in different experimental and human models. This translational approach resulted in further stressing the concept that this topic should be expanded in the future not only to better understand how oxidative stress may be linked to a liver damage but also, perhaps more important, how this may be the target for better, more focused treatments. In parallel, understanding how alteration of the redox balance may be associated with liver damage may help define sensitive and ideally early biomarkers of the disorder.

The application of quantification techniques in proteomics for biomedical research

The systematic analysis of biological processes requires an understanding of the quantitative expression patterns of proteins, their interacting partners and their subcellular localization. This information was formerly difficult to accrue as the relative quantification of proteins relied on antibody-based methods and other approaches with low throughput. The advent of soft ionization techniques in mass spectrometry plus advances in separation technologies has aligned protein systems biology with messenger RNA, DNA, and microarray technologies to provide data on systems as opposed to singular protein entities. Another aspect of quantitative proteomics that increases its importance for the coming few years is the significant technical developments underway both for high pressure liquid chromatography and mass spectrum devices. Hence, robustness, reproducibility and mass accuracy are still improving with every new generation of instruments. Nonetheless, the methods employed require validation and comparison to design fit for purpose experiments in advanced protein analyses. This review considers the newly developed systematic protein investigation methods and their value from the standpoint that relative or absolute protein quantification is required de rigueur in biomedical research.

CIP2A is highly expressed in hepatocellular carcinoma and predicts poor prognosis

BACKGROUND

Cancerous inhibitor of protein phosphatase 2A (CIP2A) is highly expressed in hepatocellular carcinoma (HCC) and promotes cell proliferation, cell invasion, and aggressive tumor behavior. However, there have been few studies on the usefulness of CIP2A as an independent prognostic index of HCC. In the current study, the aim was to explore the association between CIP2A expression and prognosis in HCC.

METHODS

The expression of CIP2A and c-MYC was examined by immunohistochemistry in 136 HCC specimens. CIP2A mRNA expression in 27 HCC tissues was also analyzed using quantitative reverse-transcription polymerase chain reaction. The prognostic significance was analyzed by the Kaplan-Meier survival method and log-rank test. Cox regression was adopted for univariate and multivariate analysis of prognostic factors.

RESULTS

CIP2A protein was found to be highly expressed in human liver cancer samples (85/136, 62.5%) and correlated with poor survival (P<0.05). The liver cancer tissues examined exhibited much higher levels of CIP2A mRNA compared with their corresponding normal tissues (19/27, 70.3%). Furthermore, CIP2A mRNA levels were correlated with c-MYC mRNA levels. In addition, the highly expressed CIP2A was associated with recurrence (P=0.014) and invasion (P=0.017) of HCC. Patients with high CIP2A expression had both poorer overall survival (OS) and disease-free survival (DFS). On multivariate analysis, the CIP2A status was a significant prognostic factor for OS and DFS (P=0.017, P=0.026, respectively).

CONCLUSIONS

CIP2A overexpression may be useful as an independent prognostic biomarker for OS and DFS of HCC.

Current advantages in the application of proteomics in inflammatory bowel disease

Since the formulation of the concept of proteomics, a plethora of proteomic technologies have been developed in order to study proteomes. In inflammatory bowel disease (IBD), several studies use proteomics to try to better understand the disease and discover molecules which can be used as biomarkers. Biomarkers should be able to be used for diagnosis, therapy and prognosis. Although several biomarkers have been discovered, few biomarkers have clinical value. In this review, we analyze and report the current use of proteomic techniques to highlight biomarkers characterizing IBD, and different stages of disease activity. We also report the biomarkers and their potential clinical value.

Promising Urinary Protein Biomarkers for the Early Detection of Hepatocellular Carcinoma among High-Risk Hepatitis C Virus Egyptian Patients

Hepatocellular Carcinoma is a major healthcare problem, representing the third most common cause of cancer-related mortality worldwide. There are 130 million Hepatitis C virus infected patients worldwide who are at a high-risk for developing Hepatocellular Carcinoma. Due to the fact that reliable parameters and/or tools for the early detection of Hepatocellular Carcinoma among high-risk individuals are severely lacking, Hepatocellular Carcinoma patients are always diagnosed at a late stage where surgical solutions or effective treatment are not possible. Urine was collected from 106 Hepatitis C infected patients patients, 32 of whom had already developed Hepatocellular Carcinoma and 74 patients who were diagnosed as Hepatocellular Carcinoma -free at the time of initial sample collection. In addition to these patients, urine samples were also collected from 12 healthy control individuals. Total urinary proteins were isolated from the urine samples and LC-MS/MS was used to identify potential protein HCC biomarker candidates. This was followed by validating relative expression levels of proteins present in urine among all the patients using quantitative real time-PCR. This approach revealed that significant over-expression of three proteins: DJ-1, Chromatin Assembly Factor-1 (CAF-1) and Heat Shock Protein 60 (HSP60), was a characteristic event among Hepatocellular Carcinoma - post Hepatitis C virus infected patients. As a single-based Hepatocellular Carcinoma biomarker, CAF-1 over-expression identified Hepatocellular Carcinoma among Hepatitis C virus infected patients with a specificity of 90%, sensitivity of 66% and with an overall diagnostic accuracy of 78%. Moreover, the CAF-1/HSP60 tandem identified Hepatocellular Carcinoma among Hepatitis C virus infected patients with a specificity of 92%, sensitivity of 61% and with an overall diagnostic accuracy of 77%.

Serum anti-Ku86 is a potential biomarker for early detection of hepatitis C virus-related hepatocellular carcinoma

Hepatocellular carcinoma (HCC), the predominant form of primary liver cancer, is one of the most common cancers worldwide and the third most common cause of cancer-related death. Imaging studies including ultrasound and computed tomography are recommended for early detection of HCC, but they are operator dependent, costly and involve radiation. Therefore, there is a need for simple and sensitive serum markers for the early detection of hepatocellular carcinoma (HCC). In our recent proteomic studies, a number of proteins overexpressed in HCC tissues were identified. We thought if the serum autoantibodies to these overexpressed proteins were detectable in HCC patients. Of these proteins, we focused on Ku86, a nuclear protein involved in multiple biological processes and aimed to assess the diagnostic value of serum anti-Ku86 in the early detection of HCC. Serum samples were obtained prior to treatment from 58 consecutive patients with early or relatively early hepatitis C virus (HCV)-related HCC and 137 patients with HCV-related liver cirrhosis without evidence of HCC. Enzyme immunoassays were used to measure serum levels of autoantibodies. Serum levels of anti-Ku86 antibodies were significantly elevated in HCC patients compared to those in liver cirrhosis patients (0.41±0.28 vs. 0.18±0.08Abs at 450nm, P<0001). Setting the cut-off level to give 90% specificity, anti-Ku86 was positive in 60.7% of stage I solitary tumor <2cm in diameter, whereas the sensitivities of alpha-fetoprotein (AFP) and protein induced by vitamin K absence or antagonist II (PIVKA-II) were 17.8% and 21.4%, respectively. The results of ROC analyses indicated the better performance of anti-Ku86 for early detection of HCC. Serum anti-Ku86 levels decreased after surgical resection of the tumors in the 12 HCC cases tested, Elevation of anti-Ku86 in solid tumors other than liver was minimal. Serum anti-Ku86 is a potential biomarker for early detection of HCV-related HCC. Further studies in a larger number of HCC patients with various etiologies are needed to further evaluate the diagnostic and pathophysiological roles of elevation of serum anti-Ku86 in early HCC.

Co-expression of XIAP and cyclin D1 complex correlates with a poor prognosis in patients with hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors in the world. Despite improved diagnosis and treatment, the prognosis for HCC patients remains poor. The goal of this study was to identify key regulatory proteins and signaling pathways important for cell apoptosis and proliferation as biomarkers for prognostication and targeted therapy. Protein Pathway Array was applied to screen 38 signaling proteins and phosphoproteins in 12 paired HCC tumors and surrounding benign tissues and found that 20 of them, including XIAP, CDK4, CDK6, and Cyclin D1, were overexpressed in HCC tissues. Immunostaining results of XIAP, CDK4, and Cyclin D1 in an additional 59 HCC tissues showed that the expression of XIAP correlated with the expression of CDK4/Cyclin D1, and that the increased expression of these proteins correlated with poor overall survival in these patients. Further studies using the HCC Huh7 cell line transfected with XIAP siRNA or expression vector demonstrated that XIAP regulated the expression of CDK4, CDK6, and Cyclin D1 via NF-êB and PTEN pathways. Finally, inhibition of XIAP using embelin, a XIAP-specific small molecule, leads to an increased apoptosis and decreased cell proliferation via arrest at G1 phase. Taken together, XIAP is a central modulator regulating cell apoptosis and cell cycle progression. Therefore, XIAP together with cell cycle regulatory proteins can be used as prognostic markers and therapeutic targets.

Serum proteomic profiling reveals that pretreatment complement protein levels are predictive of esophageal cancer patient response to neoadjuvant chemoradiation

OBJECTIVE

To identify serum-based biomarkers predicting response to neoadjuvant chemoradiotherapy (neo-CRT) in esophageal cancer.

PURPOSE

Increasingly, the standard of care for esophageal cancer involves neo-CRT followed by surgery. The identification of biomarkers predicting response to therapy may represent a major advance, enabling clinical trials and improved outcomes.

BACKGROUND DATA

Patients with esophageal cancer (n = 31) received a standard neo-CRT regimen. Histopathologic response to therapy was assessed by using the Mandard tumor regression grade (TRG) classification. Serum was collected pretreatment and at 24-hour and 48-hour time points into treatment. Serum samples were analyzed by using Surface-enhanced laser desorption/ionization time-of-flight mass spectrometry and enzyme-linked immunosorbent assay. A leave-one-out cross-validation predictive algorithm assessed the ability of validated biomarkers to correctly predict therapeutic outcome.

RESULTS

Fifty-one percent (16) of patients were poor responders (TRG 3-5), whereas 49% (15) responded well (TRG 1-2). On CM10 biochips, serum expression of 9 protein peaks was significantly different between the response groups. Two differential spectrum peaks were identified as complement C4a and C3a and were subsequently analyzed by enzyme-linked immunosorbent assay. Pretreatment serum C4a and C3a levels were significantly higher in poor responders versus good responders. Subdivision of the response groups by TRG indicated an inverse correlation between levels of C4a and C3a and pathological response to neo-CRT. The leave-one-out cross-validation analysis revealed that these serum proteins could predict response to neo-CRT with a sensitivity and specificity of 78.6% and 83.3%, respectively.

CONCLUSIONS

This translational application of proteomics technology identifies pretreatment serum levels of C4a and C3a as predictive biomarkers of response. Large validation studies in an independent cohort are merited.

Proteomic identification of CIB1 as a potential diagnostic factor in hepatocellular carcinoma

Hepatocellular carcinoma (HCC), among the most common malignancies worldwide, remains a major threat to public health, and there is an urgent need to identify novel biomarkers for diagnosis, prognosis and targets for anti-cancer treatment. In this study, two-dimensional polyacrylamide gel electrophoresis coupled with ESI-Q-TOF MS/MS analysis was used to identify differentially expressed proteins among the HCC tumour centre, tumour margin and nontumourous liver tissues. In total, 52 spots with significant alteration were positively identified byMS/MSanalysis. Altered expression of representative proteins, including CIB1, was validated by Western blotting. Immunostaining suggested an increase tendency of CIB1 expression from nontumourous liver tissue to tumour centre. Knockdown of CIB1 expression by RNA interference led to the significant suppression of the cell growth in hepatoma HepG2 cells. These data suggest that CIB1 may be used as a novel prognostic factor and possibly an attractive therapeutic target for HCC.

Proteomics of hepatocellular carcinoma in Chinese patients

Hepatocellular carcinoma (HCC) is a malignant tumor of liver that causes approximately half a million deaths each year, of which over half of the cases are diagnosed in China. Because of its asymptomatic nature, HCC is usually diagnosed at late and advanced stages, for which there are no effective therapies. Thus, biomarkers for early detection and molecular targets for treating HCC are urgently needed. With the advent of high-throughput omics technologies, we have begun to mine the genomics and proteomics information of HCC, and most importantly, these data can be integrated with clinical annotations of the patients. Such new horizons of integrated profiling informatics have allowed us to search for and better identify clinically useful biomarkers and therapeutic targets for cancers including HCC. Capitalizing the large clinical samples cohort (over 100 pairs of tumor and matched adjacent nontumor tissues of HCC), we herein discuss the use of proteomics approach to identify biomarkers that are potentially useful for (1) discrimination of tumorous from nonmalignant tissues, (2) detection of small-sized and early stage of HCC, and (3) prediction of early disease relapse after hepatectomy.

α-2-HS-glycoprotein is a potential marker predicting hepatitis B e antigen seroconversion in patients with chronic hepatitis B during treatment with pegylated interferon alpha-2b

The efficacy of interferon (IFN) is limited in about 1/3 of patients with chronic hepatitis B (CHB). We used two-dimensional electrophoresis (2-DE)-based proteomic strategies to identify potential serum markers predicting hepatitis B e antigen (HBeAg) seroconversion in these patients during IFN therapy. Two groups of patients were enrolled: training and validation. In the training group, 2-DE experiments and subsequent identification of altered levels of proteins showed that α-2-HS-glycoprotein, leucine-rich α-2-glycoprotein, and haptoglobin were significantly upregulated as compared with baseline levels in the HBeAg seroconversion group, whereas apolipoprotein C-III precursor, leucine-rich α-2-glycoprotein, and α-albumin were downregulated in the non-seroconversion group. For patients with HBeAg seroconversion in the training group, Western blot analyses showed that α-2-HS-glycoprotein levels in 75% of patients were significantly upregulated at the end of the treatment as compared with baseline levels. Subsequent experiments in the validation group showed that α-2-HS-glycoprotein levels were significantly increased at week 4 in 83.33% of patients in the HBeAg seroconversion group. Dynamic changes in the serum level of α-2-HS-glycoprotein may be a potential early marker for predicting HBeAg seroconversion during IFN treatment for CHB.

Proteomic mining in the dysplastic liver of WHV/c-myc mice--insights and indicators for early hepatocarcinogenesis

Because of the asymptomatic process of carcinogenesis, the early detection of cancers such as hepatocellular carcinoma (HCC) is very challenging. Tumor-prone transgenic mouse models of oncogenesis can provide a stable and powerful tool for the analysis of cancer initiation, and are therefore promising for the discovery of early putative biomarkers of HCC. Using a label-free proteomic quantification strategy, we comprehensively investigated the protein expression profile in the livers of three 2-month-old WHV/c-myc mice at the dysplastic stage, with age-matched wt-C57 mice as controls. We identified 2781 proteins, 540 of which were differentially expressed. These proteins successfully characterized certain precancerous biological processes and alterations in transcriptional regulators before tumor onset. Two candidates, FK506-binding protein 4 (FKBP52) and ferritin heavy chain, were taken as examples for a search from the mouse model to clinical human tissues. Their levels in serum samples were determined by western blotting, and showed a noteworthy ability to distinguish between HCC and control cases. Immunohistochemical analysis with tissue microarrays confirmed the differential expression of FKBP52 between HCC and the paired controls (P < 0.001). The regulation of FKBP52 was also discovered to be relevant to HCC staging, with a dramatic decline at stage III (P < 0.05). The potentials of the candidate pool in this study were discussed in terms of delineating c-myc-induced hepatocarcinogenesis and facilitating biomarker discovery for early HCC diagnosis.

Prognostic significance and therapeutic potential of eukaryotic translation initiation factor 5A (eIF5A) in hepatocellular carcinoma

Using comparative proteomic and genomic approaches, the authors identified eukaryotic translation initiation factor 5A (eIF5A) as an oncofetal molecule highly abundant in mouse embryonic livers and human hepatocellular carcinoma (HCC) cell lines. To evaluate the oncogenic role and prognostic significance of eIF5A in HCC, we investigate the expression patterns of the two isoforms (eIF5A1 and eIF5A2) in a cohort of 258 HCC cases by cDNA microarray. Both eIF5A isoforms were expressed in the tumors, and clinically correlated eIF5A1 with more numbers of tumor nodules and eIF5A2 with tumor venous infiltration in HCC. In a separate cohort of 50 HCCs, high level of eIF5A2, but not eIF5A1, was associated with elevated levels of deoxyhypusine synthase and deoxyhypusine hydroxylase that catalyze post-translational hypusination of eIF5A protein. Interestingly, N1-guanyl-1,7-diaminoheptane (GC7), which is an inhibitor for the first step of eIF5A hypusination, was shown to significantly impair the cell proliferation and invasion of primary HCC cells (HepG2 and Hep3B). To further demonstrate the tumorigenic role associated with eIF5A, a drastic reduction of cell proliferation was associated with suppression of eIF5A2 by transfecting Hep3B, H2-P and H2-M HCC cells expressing high level of this isoform using small interfering RNA (siRNA) against eIF5A2. For these assays, a milder response was usually observed in normal hepatocyte cell line. Therefore, these findings suggest that eIF5A plays an important role in HCC tumorigenesis and metastasis, and targeting eIF5A hypusination by GC7 inhibitor or eIF5A2 by RNA interference (RNAi) may offer new therapeutic alternatives to HCC patients.

Proteomic analysis of differentially expressed proteins in hepatitis B virus-related hepatocellular carcinoma tissues

BACKGROUND

Hepatocellular carcinoma (HCC), a major cause of cancer death in China, is preceded by chronic hepatitis and liver cirrhosis (LC). Although hepatitis B virus (HBV) has been regarded as a clear etiology of human hepatocarcinogenesis, the mechanism is still needs to be further clarified. In this study, we used a proteomic approach to identify the differential expression protein profiles between HCC and the adjacent non-tumorous liver tissues.

METHODS

Eighteen cases of HBV-related HCC including 12 cases of LC-developed HCC and 6 cases of chronic hepatitis B (CHB)-developed HCC were analyzed by two-dimensional electrophoresis (2-DE) combined with matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS), and the results were compared to those of paired adjacent non-tumorous liver tissues.

RESULTS

A total of 17 differentially expressed proteins with diverse biological functions were identified. Among these, 10 proteins were up-regulated, whereas the other 7 proteins were down-regulated in cancerous tissues. Two proteins, c-Jun N-terminal kinase 2 and ADP/ATP carrier protein were found to be up-regulated only in CHB-developed HCC tissues. Insulin-like growth factor binding protein 2 and Rho-GTPase-activating protein 4 were down-regulated in LC-developed and CHB-developed HCC tissues, respectively. Although 11 out of these 17 proteins have been already described by previous studies, or are already known to be involved in hepatocarcinogenesis, this study revealed 6 new proteins differentially expressed in HBV-related HCC.

CONCLUSION

These findings elucidate that there are common features between CHB-developed HCC and LC-developed HCC. The identified proteins are valuable for studying the hepatocarcinogenesis, and may be potential diagnostic markers or therapeutic targets for HBV-related HCC.

Application of proteomics in the study of digestive system tumors

Proteomics is the study of all proteins present in a given organism, tissue, cell, and even organelle. Two-dimensional gel electrophoresis and mass spectrography are two core technologies in proteomics. Proteomic studies can help us understand the life as a whole. As a new platform for tumor research, proteomics is of important significance for early diagnosis, biomarker discovery, therapy and discovery of novel drug targets for esophageal carcinoma, gastric cancer, liver cancer, pancreatic cancer and colorectal cancer. Thus, it has potential broad application prospects.

Proteomic expression signature distinguishes cancerous and nonmalignant tissues in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is an aggressive liver cancer but clinically validated biomarkers that can predict natural history of malignant progression are lacking. The present study explored the proteome-wide patterns of HCC to identify biomarker signature that could distinguish cancerous and nonmalignant liver tissues. A retrospective cohort of 80 HBV-associated HCC was included and both the tumor and adjacent nontumor tissues were subjected to proteome-wide expression profiling by 2-DE method. The subjects were randomly divided into the training (n = 55) and validation (n = 25) subsets, and the data analyzed by classification-and-regression tree algorithm. Protein markers were characterized by MALDI-ToF/MS and confirmed by immunohistochemistry, Western blotting and qPCR assays. Proteomic expression signature composed of six biomarkers (haptoglobin, cytochrome b5, progesterone receptor membrane component 1, heat shock 27 kDa protein 1, lysosomal proteinase cathepsin B, keratin I) was developed as a classifier model for predicting HCC. We further evaluated the model using both leave-one-out procedure and independent validation, and the overall sensitivity and specificity for HCC both are 92.5%, respectively. Clinical correlation analysis revealed that these biomarkers were significantly associated with serum AFP, total protein levels and the Ishak's score. The described model using biomarker signatures could accurately distinguish HCC from nonmalignant tissues, which may also provide hints on how normal hepatocytes are transformed to malignant state during tumor progression.

Applications of proteomics in the study of inflammatory bowel diseases: Current status and future directions with available technologies

Inflammatory bowel diseases (IBD) are chronic, heterogeneous, and multifactorial intestinal inflammatory disorders. Major challenges in IBD research include identification of major pathogenic alterations of genes/proteins as well as effective biomarkers for early diagnosis, prognosis, and prediction of therapeutic response. Since proteins govern cellular structure and biological function, a wide selection of proteomic approaches enables effective characterization of IBD pathogenesis by investigating the dynamic nature of protein expression, cellular and subcellular distribution, posttranslational modifications, and interactions at both the cellular and subcellular levels. The aims of this review are to 1) highlight the current status of proteomic studies of IBD, and 2) introduce the available and emerging proteomic technologies that have potential applications in the study of IBD. These technologies include various mass spectrometry technologies, quantitative proteomics (2D-PAGE, ICAT, SILAC, iTRAQ), protein/antibody arrays, and multi-epitope-ligand cartography. This review also presents information and methodologies, from sample selection and enrichment to protein identification, that are not only essential but also particularly relevant to IBD research. The potential future application of these technologies is expected to have a significant impact on the discovery of novel biomarkers and key pathogenic factors for IBD.

Comparative analysis of the liver and plasma proteomes as a novel and powerful strategy for hepatocellular carcinoma biomarker discovery

The extraordinary developments made in the past decade in proteomic technologies, in particular in mass spectrometry, have enabled investigators to consider designing studies to search for diagnostic and therapeutic biomarkers by scanning complex proteome samples. We developed a method based on extensive fractionation of intact proteins, to comprehensively and quantitatively profile the liver and plasma proteomes in health and disease. We have applied this method to samples collected from patients with early hepatocellular carcinoma (HCC) and from patients with liver cirrhosis as well as to samples collected from three mouse models of HCC. This method allowed for the identification of proteins that differ in expression levels in liver tissue or in plasma with disease progression from liver fibrosis, cirrhosis or steatohepatitis to HCC. The comparative analysis of the liver and plasma proteomes generated from human and mouse specimens, constitutes a novel and powerful strategy for HCC biomarker discovery.

Mass spectrometry based targeted protein quantification: methods and applications

The recent advance in technology for mass spectrometry-based targeted protein quantification has opened new avenues for a broad range of proteomic applications in clinical research. The major breakthroughs are highlighted by the capability of using a "universal" approach to perform quantitative assays for a wide spectrum of proteins with minimum restrictions and the ease of assembling multiplex detections in a single measurement. The quantitative approach relies on the use of synthetic stable isotope labeled peptides or proteins, which precisely mimic their endogenous counterparts and act as internal standards to quantify the corresponding candidate proteins. This report reviews recently developed platform technologies for emerging applications of clinical proteomics and biomarker development.

Surface enhanced laser desorption/ionization profiling: New diagnostic method of HBV-related hepatocellular carcinoma

BACKGROUND AND AIM

To screen for serum biomarkers of HBV-related hepatocellular carcinoma (HCC) and HBV-related liver cirrhosis (LC) in an attempt to seek a new method for differential diagnosis of HCC and LC using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS) techniques.

METHODS

Using SELDI-TOF-MS, serum proteins/peptide profiles on the immobilized metal ion affinity capture (IMAC) protein chips were obtained from 29 HCC patients and 30 LC patients. Discriminant analysis was carried out to establish new diagnostic methods using protein/peptide peaks with or without alpha-fetoprotein (AFP).

RESULTS

Forty-five protein/peptide peaks changed much more in the HCC group than they did in the LC group. Discriminant analysis using the Wilcoxon rank-sum test showed high sensitivity and specificity in distinguishing HCC from LC. The most significantly differentiating peak, 3892, offered 69.0% sensitivity, 83.3% specificity and 80% positive predictive value in distinguishing HCC and LC. Interestingly, six HCC patients with negative serum AFP were confirmed by peak 3892. The combination of multi-protein peaks (m/z = 9297, 29 941) with AFP offered an 82.8% sensitivity, 93.3% specificity and 92.3% positive predictive value, which was much better than AFP alone (P = 0.013).

CONCLUSIONS

Special proteins/peptides of serum may differentiate HBV-related HCC and HBV-related LC, indicating that SELDI-TOF-MS may be useful to distinguish HCC from LC with the proper discriminant analytical method. SELDI peak 3892 may be a complementary diagnostic marker to positive AFP for HCC and a potential marker for the diagnosis of AFP-negative HCC as well.

Senescence marker protein 30 in acute liver failure: validation of a mass spectrometry proteomics assay

BACKGROUND

Our previous proteomic study showed that the senescence marker protein (SMP30) is selectively present in the plasma of a murine model of acute liver failure (ALF). The aim of this study was to validate this SMP30 expression in the plasma and liver tissues of mice and humans with ALF.

METHODS

After the proteomic analysis of plasma from a murine model of D-galactosamine/lipopolysaccharide (GalN/LPS)-induced ALF by two-dimensional electrophoresis (2-DE) and mass spectrometry, the expression levels of SMP30 in the plasma and liver tissues were validated by western blot and RT-PCR analyses. These results were then confirmed in plasma samples from humans.

RESULTS

These data validate the results of 2-DE, and western blot showed that SMP30 protein levels were only elevated in the plasma of ALF mice. Further analysis revealed that GalN/LPS induced the downregulation of SMP30 protein levels in liver tissues (by approximately 25% and 16% in the GalN/LPS-treated mice and in the treated mice that survived, respectively; P < 0.01). Hepatic SMP30 mRNA levels decreased by about 90% only in the mice that survived the GalN/LPS treatment. Importantly, plasma obtained from patients with ALF also contained higher levels of SMP30, about (3.65 +/- 0.34) times those observed in healthy volunteers.

CONCLUSION

This study shows that SMP30 is not only a potential biomarker for the diagnosis and even prognosis of ALF. It also plays a very important role in a self-protective mechanism in survival and participates in the pathophysiological processes of ALF.

Diagnosis of hepatic nodules 20 mm or smaller in cirrhosis: Prospective validation of the noninvasive diagnostic criteria for hepatocellular carcinoma

This study prospectively evaluates the accuracy of contrast-enhanced ultrasound (CEUS) and dynamic magnetic resonance imaging (MRI) for the diagnosis of nodules 20 mm or smaller detected during ultrasound (US) surveillance. We included 89 patients with cirrhosis [median age, 65 years; male 53, hepatitis C virus 68, Child-Pugh A 80] without prior hepatocellular carcinoma (HCC) in whom US detected a small solitary nodule (mean diameter, 14 mm). Hepatic MRI, CEUS, and fine-needle biopsy (gold standard) (FNB) were performed at baseline. Non-HCC cases were followed (median 23 months) by CEUS/3 months and MRI/6 months. FNB was repeated up to 3 times and on detection of change in aspect/size. Intense arterial contrast uptake followed by washout in the delayed/venous phase was registered as conclusive for HCC. Final diagnoses were: HCC (n = 60), cholangiocarcinoma (n = 1), and benign lesions (regenerative/dysplastic nodule, hemangioma, focal nodular hyperplasia) (n = 28). Sex, cirrhosis cause, liver function, and alpha-fetoprotein (AFP) levels were similar between HCC and non-HCC groups. HCC patients were older and their nodules significantly larger (P < 0.0001). First biopsy was positive in 42 of 60 HCC patients. Sensitivity, specificity, and positive and negative predictive values of conclusive profile were 61.7%, 96.6%, 97.4%, and 54.9%, for MRI, 51.7%, 93.1%, 93.9%, and 50.9%, for CEUS. Values for coincidental conclusive findings in both techniques were 33.3%, 100%, 100%, and 42%. Thus, diagnosis of HCC 20 mm or smaller can be established without a positive biopsy if both CEUS and MRI are conclusive. However, sensitivity of these noninvasive criteria is 33% and, as occurs with biopsy, absence of a conclusive pattern does not rule out malignancy. These results validate the American Association for the Study of Liver Disease (AASLD) guidelines.

Oncoproteomics of hepatocellular carcinoma: from cancer markers' discovery to functional pathways

Hepatocellular carcinoma (HCC) is a heterogeneous cancer with no promising treatment and remains one of the most prevailing and lethal malignancies in the world. Researchers in many biological areas now routinely identify and characterize protein markers by a mass spectrometry-based proteomic approach, a method that has been commonly used to discover diagnostic biomarkers for cancer detection. The proteomic research platforms span from the classical two-dimensional polyacrylamide gel electrophoresis (2-DE) to the latest Protein Chip or array technology, which are often integrated with the MALDI (matrix-assisted laser-desorption ionization), SELDI (surface-enhanced laser desorption/ionization) or tandem mass spectrometry (MS/MS). New advances on quantitative proteomic analysis (e.g. SILAC, ICAT, and ITRAQ) and multidimensional protein identification technology (MudPIT) have greatly enhanced the capability of proteomic methods to study the expressions, modifications and functions of protein markers. The present article reviews the latest proteomic development and discovery of biomarkers in HCC that may provide insights into the underlying mechanisms of hepatocarcinogenesis and the readiness of biomarkers for clinical uses.

Down-regulation of beta-centractin might be involved in dendritic cells dysfunction and subsequent hepatocellular carcinoma immune escape: a proteomic study

AIMS

Proteomic study was used to clarify the mechanism of hepatocellular carcinoma (HCC) immune escape concerning Dendritic cells (DCs') dysfunction and their association with HCC invasion.

METHODS

Human peripheral blood mononuclear cells (PBMCs) derived DCs from healthy donors were pulsed with soluble cell lysates prepared from different metastatic potential human HCC cell lines. The total protein of these DCs was analyzed by two-dimensional electrophoresis and Electro-Spray Mass Spectrometry. The allostimulatoy capacity and phenotype of these DCs were also evaluated. The clinical significance of beta-centractin, one of the largest quantitative changed spot, down-regulation in DCs was further evaluated in autologous PBMCs derived DCs pulsed with auto-tumor lysates in 26 HCC patients.

RESULTS

The expression of beta-centractin was found to be considerably lower either in DCs pulsed with HCCLM6 (high metastatic potential HCC cell line) lysates, accompanied by down-regulation of CD86 molecule and impaired allostimulatory capacity, than those of DCs pulsed with lysates from HCC cell lines with low or without metastatic potential or in DCs pulsed with lysates from HCC with invasiveness than those without invasiveness.

CONCLUSIONS

The down-regulation of beta-centractin in DCs pulsed with high metastatic potential HCC lysates might associate with DCs dysfunction and HCC invasiveness.

Altered protein expression at early-stage rat hepatic neoplasia

Protein expression patterns were analyzed in a rat model of hepatic neoplasia to detect changes reflecting biological mechanism or potential therapeutic targets. The rat resistant hepatocyte model of carcinogenesis was studied, with a focus on the earliest preneoplastic lesion visible in the liver, the preneoplastic hyperplastic nodule. Expression differences were shown by two-dimensional polyacrylamide gel electrophoresis and image analysis. Polypeptide masses were measured by peptide mass fingerprinting using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF) and their sequences were obtained by tandem mass spectrometry. Alterations in expression of cytoskeletal and functional proteins were demonstrated, consistent with biological changes known to occur in the preneoplastic cells. Of particular interest was the differential expression of a serine protease inhibitor (serpin) with a role implicated in angiogenesis. Serpin, implicated in the inhibition of angiogenesis, is present in normal liver but has greatly reduced expression at the preneoplastic stage of liver cancer development. Immunofluorescence microscopy with antibodies to this serpin, kallistatin, supports the proteomic identification. Immunofluorescence microscopy with antibodies to the blood vessel marker von Willebrand factor provides evidence for neovascularization in the liver containing multiple preneoplastic nodules. These observations suggest that at an early stage of liver carcinogenesis reduction or loss of angiogenesis inhibitors may contribute to initiation of neoangiogenesis. A number of other identified proteins known to be associated with hepatomas are also present at early-stage neoplasia.