Terence C.W. Poon

Comprehensive Proteomic Profiling Identifies Serum Proteomic Signatures for Detection of Hepatocellular Carcinoma and Its Subtypes

BACKGROUND Detection of hepatocellular carcinoma (HCC) in patients with chronic liver disease (CLD) is difficult. We investigated the use of comprehensive proteomic profiling of sera to differentiate HCC from CLD. METHODS Proteomes in sera from 20 CLD patients with alpha-fetoprotein (AFP) <500 microg/L (control group) and 38 HCC patients (disease group) were profiled by anion-exchange fractionation (first dimension), two types (IMAC3 copper and WCX2) of ProteinChip Arrays (second dimension), and time-of-flight mass spectrometry (third dimension). Bioinformatic tests were used to identify tumor-specific proteomic features and to estimate the values of the tumor-specific proteomic features in the diagnosis of HCC. Cross-validation was performed, and we also validated the models with pooled sera from the control and disease groups, serum from a CLD patient with AFP >500 microg/L, and postoperative sera from two HCC patients. RESULTS Among 2384 common serum proteomic features, 250 were significantly different between the HCC and CLD cases. Two-way hierarchical clustering differentiated HCC and CLD cases. Most HCC cases with advanced disease were clustered together and formed two subgroups that contained significantly more cases with lymph node invasion or distant metastasis. For differentiation of HCC and CLD by an artificial network (ANN), the area under the ROC curve was 0.91 (95% confidence interval, 0.82-1.01; P <0.0005) for all cases and 0.954 (95% confidence interval, 0.881-1.027; P <0.0005) for cases with nondiagnostic serum AFP (<500 microg/L). At a specificity of 90%, the sensitivity was 92%. Both cluster analysis and ANN correctly classified the pooled serum samples, the CLD serum sample with increased AFP, and the HCC patient in complete remission. CONCLUSION Tumor-specific proteomic signatures may be useful for detection and classification of hepatocellular cancers.

Prognostic significance of tumor angiogenesis, Ki 67, p53 oncoprotein, epidermal growth factor receptor and HER2 receptor protein expression in undifferentiated nasopharyngeal carcinoma—a prospective study†

This study prospectively examines the prognostic role of p53 oncoprotein (p53), Ki67‐antigen (Ki67), tumor angiogenesis (MVD), epidermal growth factor receptor (EGFR), and HER2 receptor protein (HER2) expression in Chinese with undifferentiated nasopharyngeal carcinoma (NPC).

Host-response biomarkers for diagnosis of late-onset septicemia and necrotizing enterocolitis in preterm infants

Preterm infants are highly susceptible to life-threatening infections that are clinically difficult to detect, such as late-onset septicemia and necrotizing enterocolitis (NEC). Here, we used a proteomic approach to identify biomarkers for diagnosis of these devastating conditions. In a case-control study comprising 77 sepsis/NEC and 77 nonsepsis cases (10 in each group being monitored longitudinally), plasma samples collected at clinical presentation were assessed in the biomarker discovery and independent validation phases. We validated the discovered biomarkers in a prospective cohort study with 104 consecutively suspected sepsis/NEC episodes. Proapolipoprotein CII (Pro-apoC2) and a des-arginine variant of serum amyloid A (SAA) were identified as the most promising biomarkers. The ApoSAA score computed from plasma apoC2 and SAA concentrations was effective in identifying sepsis/NEC cases in the case-control and cohort studies. Stratification of infants into different risk categories by the ApoSAA score enabled neonatologists to withhold treatment in 45% and enact early stoppage of antibiotics in 16% of nonsepsis infants. The negative predictive value of this antibiotic policy was 100%. The ApoSAA score could potentially allow early and accurate diagnosis of sepsis/NEC. Upon confirmation by further multicenter trials, the score would facilitate rational prescription of antibiotics and target infants who require urgent treatment.

Proteome analysis and its impact on the discovery of serological tumor markers.

BACKGROUND Proteomics is a rapidly growing field of research that is becoming increasingly important as we enter the post-genome era. Remarkable improvements in the technologies of high-resolution two-dimensional polyacrylamide gel electrophoresis (2D PAGE) and mass spectrometry (MS) have marked the start of proteome analysis and its application to the study of human diseases. Besides studying the proteins involved in carcinogenesis, it is also applicable to the discovery of serological tumor markers for clinical uses, such as for hepatocellular carcinoma. CONCLUSIONS The combination of 2D PAGE and MS is the most widely used technique for proteomics, although other more automated high-throughput techniques are being developed.

Hepatocellular carcinoma-derived exosomes promote motility of immortalized hepatocyte through transfer of oncogenic proteins and RNAs

Exosomes are increasingly recognized as important mediators of cell-cell communication in cancer progression through the horizontal transfer of RNAs and proteins to neighboring or distant cells. Hepatocellular carcinoma (HCC) is a highly malignant cancer, whose metastasis is largely influenced by the tumor microenvironment. The possible role of exosomes in the interactions between HCC tumor cell and its surrounding hepatic milieu are however largely unknown. In this study, we comprehensively characterized the exosomal RNA and proteome contents derived from three HCC cell lines (HKCI-C3, HKCI-8 and MHCC97L) and an immortalized hepatocyte line (MIHA) using Ion Torrent sequencing and mass spectrometry, respectively. RNA deep sequencing and proteomic analysis revealed exosomes derived from metastatic HCC cell lines carried a large number of protumorigenic RNAs and proteins, such as MET protooncogene, S100 family members and the caveolins. Of interest, we found that exosomes from motile HCC cell lines could significantly enhance the migratory and invasive abilities of non-motile MIHA cell. We further demonstrated that uptake of these shuttled molecules could trigger PI3K/AKT and MAPK signaling pathways in MIHA with increased secretion of active MMP-2 and MMP-9. Our study showed for the first time that HCC-derived exosomes could mobilize normal hepatocyte, which may have implication in facilitating the protrusive activity of HCC cells through liver parenchyma during the process of metastasis.

Serum Proteomic Fingerprints of Adult Patients with Severe Acute Respiratory Syndrome

Abstract Background: Severe acute respiratory syndrome (SARS) is an emerging infectious disease caused by a new coronavirus strain, SARS-CoV. Specific proteomic patterns might be present in serum in response to the infection and could be useful for early detection of the disease. Methods: Using surface-enhanced laser desorption/ionization (SELDI) ProteinChip technology, we profiled and compared serum proteins of 39 patients with early-stage SARS infection and 39 non-SARS patients who were suspected cases during the SARS outbreak period. Proteomic patterns associated with SARS were identified by bioinformatic and biostatistical analyses. Features of interest were then purified and identified by tandem mass spectrometry. Results: Twenty proteomic features were significantly different between the 2 groups. Fifteen were increased in the SARS group, and 5 were decreased. Their concentrations were correlated with 2 or more clinical and/or biochemical variables. Two were correlated with the SARS-CoV viral load. Hierarchical clustering analysis showed that a majority of the SARS patients (95%) had similar serum proteomic profiles and identified 2 subgroups with poor prognosis. ROC curve analysis identified individual features as potential biomarkers for SARS diagnosis (areas under ROC curves, 0.733–0.995). ROC curve areas were largest for an N-terminal fragment of complement C3c α chain (m/z 28 119) and an internal fragment of fibrinogen α-E chain (m/z 5908). Immunoglobulin κ light chain (m/z 24 505) positively correlated with viral load. Conclusions: Specific proteomic fingerprints in the sera of adult SARS patients could be used to identify SARS cases early during onset with high specificity and sensitivity.

Peroxisome proliferator-activated receptors gamma reverses hepatic nutritional fibrosis in mice and suppresses activation of hepatic stellate cells in vitro

Nonalcoholic steatohepatitis with fibrosis is a more severe form of nonalcoholic fatty liver disease, one of the most common liver diseases. We have previously shown that peroxisome proliferator-activated receptors gamma (PPARgamma) ligand, rosiglitazone, prevented the development of the methionine choline deficient (MCD) diet-induced fibrosing steatohepatitis. We have now tested whether overexpression of PPARgamma ameliorates established steatohepatitis and fibrosis. Male C57BL6 mice fed with MCD diet for 8 weeks developed hepatic fibrosis with increased hepatic expression of collagen1alpha(I), inhibitors of fibrosis reversal-1, regulator involved in matrix degradation-9 and connective tissue growth factor. After 2 weeks of transduction of PPARgamma through an adenovirus-expressing PPARgamma (Ad-PPARgamma), expression of these genes was reduced in a manner that paralleled the reduction in activated hepatic stellate cells (HSCs) and resolution of liver fibrosis. On the in vitro study, PPARgamma is expressed in primary quiescent HSC, but depleted in culture activated HSC. Conversely, ectopic expression of PPARgamma in activated HSC achieved the phenotypic reversal to the quiescent cell. Such induction markedly suppressed cell viability and cell proliferation, downregulated proliferating cell nuclear antigen, and caused cell cycle arrest at G0/G1 phase. Further, introduction of PPARgamma in HSC increased cell apoptosis, this was confirmed by enhanced expression of FasL, cleaved caspase-3, cleaved caspase-7 and poly ADP-ribose polymerase, indicating an extrinsic apoptosis pathway. In conclusion, the present study shows that MCD diet-induced fibrosing steatohepatitis can be reversed by overexpression of PPARgamma. It is likely that PPARgamma reverses fibrosis by reducing HSCs proliferation, inducing cell cycle arrest and apoptosis.

A novel interplay between oncogenic PFTK1 protein kinase and tumor suppressor TAGLN2 in the control of liver cancer cell motility

The PFTK1 gene encodes a cdc2-related serine/threonine protein kinase that has been shown to confer cell migratory properties in hepatocellular carcinoma (HCC). However, the prognostic value and biological mechanism by which PFTK1 promotes HCC motility remain largely unknown. Here, we showed from tissue microarray that common upregulations of PFTK1 in primary HCC tumors (n=133/180) correlated significantly with early age onset (⩽40 years), advance tumor grading and presence of microvascular invasion (P⩽0.05). To understand downstream phosphorylated substrate(s) of PFTK1, phospho-proteins in PFTK1 expressing and knockdown Hep3B cells were profiled by two-dimensional-polyacrylamide gel electrophoresis mass spectrometric analysis. Protein identification of differential spots revealed β-actin (ACTB) and transgelin2 (TAGLN2) as the two most profound phosphorylated changes affected by PFTK1. We verified the presence of TAGLN2 serine phosphorylation and ACTB tyrosine phosphorylation. Moreover, reduced TAGLN2 and ACTB phosphorylations in PFTK1-suppressed Hep3B corresponded to distinct actin depolymerizations and marked inhibition on cell invasion and motility. Given that TAGLN2 is a tumor suppressor whose function has been ascribed in cancer metastasis, we examined if TAGLN2 is an intermediate substrate in the biological path of PFTK1. We showed in PFTK1-suppressed cells that knockdown of TAGLN2 over-rode the inhibitory effect on cell invasion and motility, and a recovery on actin polymerization was evident. Interestingly, we also found that unphosphorylated TAGLN2 in PFTK1-suppressed cells elicited strong actin-binding ability, a mechanism that possibly halts the actin cytoskeleton dynamics. Site-directed mutagenesis of TAGLN2 suggested that PFTK1 regulates the actin-binding affinity of TAGLN2 through the S83 and S163 residues, which if mutated can significantly affect HCC cell motility. Taken together, our data propose a novel, oncogene-tumor suppressor interplay, where oncogenic PFTK1 confers HCC cell motility through inactivating the actin-binding motile suppressing function of TAGLN2 via phosphorylation.

Gut-associated biomarkers L-FABP, I-FABP, and TFF3 and LIT score for diagnosis of surgical necrotizing enterocolitis in preterm infants.

Objectives: To evaluate the use of gut barrier proteins, liver-fatty acid binding protein (L-FABP), intestinal-fatty acid binding protein (I-FABP), and trefoil factor 3 (TFF3), as biomarkers for differentiating necrotizing enterocolitis (NEC) from septicemic/control infants and to identify the most severely affected surgical NEC from nonsurgical NEC infants. Background: Clinical features and routine radiologic investigations have low diagnostic utilities in identifying surgical NEC patients. Methods: The diagnostic utilities of individual biomarkers and the combination of biomarkers, the LIT score, were assessed among the NEC (n = 20), septicemia (n = 40), and control groups (n = 40) in a case-control study for the identification of proven NEC and surgical NEC infants. Results: Plasma concentrations of all gut barrier biomarkers and the LIT score were significantly higher in the NEC than in the septicemia or control group (P < 0.01). Using median values of biomarkers and the LIT score in the NEC group as cutoff values for identifying NEC from septicemic/control cases, all had specificities of 95% or more and sensitivities of 50%. Significantly higher levels of biomarkers and the LIT score were found in infants with surgical NEC than in nonsurgical NEC cases (P ⩽ 0.02). The median LIT score of 4.5 identified surgical NEC cases with sensitivity and specificity of 83% and 100%%, respectively. A high LIT score of 6 identified nonsurvivors of NEC with sensitivity and specificity of 78% and 91%, respectively. Conclusions: The LIT score can effectively differentiate surgical NEC from nonsurgical NEC infants and nonsurvivors of NEC from survivors at the onset of clinical presentation. Frontline neonatologists and surgeons may, therefore, target NEC infants who are most in need of close monitoring and those who may benefit from early surgical intervention.

A double-blind randomised controlled trial of fish oil-based versus soy-based lipid preparations in the treatment of infants with parenteral nutrition-associated cholestasis.

Background: Infants receiving prolonged parenteral nutrition (PN) are at risk of PN-associated cholestasis (PNAC). This can progress to hepatic failure and death if PN cannot be discontinued. Fish oil-based parenteral lipid preparation (FOLP) has been shown to be beneficial in case studies. Objectives: (1) To evaluate whether FOLP could halt or reverse the progression of PNAC compared with soy-based parenteral lipid preparation (SLP) and (2) to assess the effects of FOLP on liver function and physical growth. Methods: Design: double-blind randomised controlled trial. Setting: level III neonatal intensive care unit. Participants: infants with PNAC (plasma-conjugated bilirubin concentration ≥34 µmol/l or 2 mg/dl) expected to be PN-dependent for >2 weeks. Intervention: to receive either FOLP or SLP at 1.5 g/kg/day. Primary outcome measure: reversal of PNAC within 4 months after commencement of lipid treatment; secondary outcomes: rate of change of weekly liver function tests, infant growth parameters, blood lipid profile and episodes of late-onset sepsis. Results: A total of 9 infants were randomised to the FOLP group and 7 to the SLP group. There was no significant difference in reversal of PNAC at 4 months between groups. Rates of increase of plasma-conjugated bilirubin and alanine aminotransferase in the SLP group were significantly greater than the FOLP group (13.5 vs. 0.6 µmol/l per week and 9.1 vs. 1.1 IU/l per week, respectively, p = 0.03). Increased enteral nutrition was associated with significant improvement of PNAC in infants receiving FOLP compared with SLP (-8.5 vs. -1.6 µmol/l per 10% increase in enteral nutrition, respectively). The study was terminated prematurely. Conclusions: progression of PNAC in PN-dependent infants can be halted by replacing SLP with FOLP and reversed by increasing the proportion of enteral nutrition in infants receiving FOLP. Replacement of SLP with FOLP in PN-dependent infants who develop PNAC may be considered.