Calreticulin binds preferentially with B cell linear epitopes of Ro60 kD autoantigen,enhancing recognition by anti-Ro60 kD autoantibodies

Calreticulin is a molecular chaperone to newly synthesized polypeptides. Previous studies suggested that calreticulin is probably a protein member of the Ro/La RNP complex. The aims of this study were (a) to investigate whether linear B cell epitopes of the Ro/La RNP complex are bound to calreticulin and (b) if the complex peptide–calreticulin is recognized specifically by anti‐Ro autoantibodies. Calreticulin was isolated from either human or pig spleen using a multi‐step purification method and found to interact preferentially with biotinylated peptides derived from the sequence of the Ro60 kD 175–184aa(10p) and 216–232aa(17p). The interaction of the peptide–calreticulin complex was favoured by the combination of heat treatment, divalent cations and ATP. La/SSB epitopes did not react with calreticulin. Peptides corresponding to La/SSB epitopes as well as the common epitope of Sm did not interact with calreticulin. Thirty‐eight anti‐Ro60 KD positive and 23 anti‐Ro60 kD negative sera of patients with systemic lupus erythematosus (SLE) and primary Sjögren's syndrome (pSS) were tested. All anti‐Ro60 kD positive sera bound the complex calreticulin‐17p, while 95% of the same sera had activity against the complex calreticulin ? 10p. Tested individually, calreticulin, pep10p and pep17p presented very low reactivity (8%, 11% and 29%, respectively) against anti‐Ro60 kD positive sera. Anti‐Ro60 KD negative sera did not exhibit significant reactivity either with calreticulin, 10ρ and 17ρ or with the complexes calreticulin ? 10p and calreticulin‐17p (<5%). These results suggest that calreticulin can induce conformation‐dependent recognition of the Ro60 kD epitopes, leading eventually to their recognition by autoantibodies. This is the first time that such a relationship is shown between a chaperone protein and fragments of an intracellular autoantigen. This work also provides insights into the understanding of mechanisms for autoantibody production. Furthermore, this association can be proved useful for the development of new sensitive assays for autoantibody detection.     

Utility of pancreatic digestive enzyme immunohistochemistry in the differential diagnosis of hepatocellular carcinoma, cholangiocarcinoma and metastatic adenocarcinoma of the liver

To test the diagnostic utility of pancreatic digestive enzyme immunohistochemistry in liver cancers, the expression of three pancreatic digestive enzymes (trypsinogen, chymotrypsinogen and pancreatic lipase) was investigated in cholangiocarcinoma (CC) (n = 42), hepatocellular carcinoma (HCC) (n = 35), combined HCC-CC (n = 11) and metastatic adenocarcinoma (MA) of the liver (n = 34; 4 gastric cancer, 5 pancreatic cancer and 25 colon cancer). In CC, 15 (36%) expressed one or more of these enzymes, while the remaining 27 (64%) did not express any enzymes. In MA, 13 (38%) expressed one or more of these enzymes, while the remaining 21 (62%) did not express any enzymes. Expression of trypsinogen, chymotrypsinogen and lipase was noted in 15 CC (36%), 11 CC (25%) and 15 CC (36%), respectively, and in 9 MA (26%), 6 MA (18%) and 13 MA (38%), respectively. There was no significant difference in the positive ratio of each enzyme between CC and MA. In positive cases, the enzymes were expressed with a cytoplasmic granular pattern. In MA, there was no significant difference in the positive ratio of the enzymes among the primary sites. In contrast to CC and MA, these enzymes were not expressed in any cases of HCC and combined HCC-CC. These data suggest that pancreatic digestive enzyme immunohistochemistry may be useful for differential diagnosis between HCC and CC or MA as well as between combined HCC-CC and CC or MA, but it is not useful for differential diagnosis between CC and MA. A positive reaction for these enzymes is indicative of CC or MA and is against the diagnosis of HCC or combined HCC-CC, and a negative reaction is noncontributory to the differential diagnosis.     

Number of mutations within CTL-defined epitopes of the hepatitis B Virus (HBV) core region is associated with HBV disease progression

The virologic determinants of progressive liver disease associated with hepatitis B virus (HBV) remain unclear. Previous investigations have associated HBV disease with specific mutations but this association may be confounded by HBV genotype, HLA haplotype of the infected individual or both. The association between non‐synonymous mutations located within putative cytotoxic T‐lymphocyte directed epitopes (CDE) of the HBV core region and disease states was investigated. Subjects infected with HBV were enrolled from a clinical cohort in Seoul, Korea, and HBV core gene sequences were analyzed for mutational patterns inside and outside of CDE with respect to subject demographics and HBV‐related disease states. No specific mutation or pattern of mutations were associated with progressive disease states; however, individuals with cirrhosis and hepatocellular carcinoma had greater numbers of non‐synonymous mutations within CDE when compared to those with chronic HBV infection who were HBeAg positive (P = 0.007 and 0.026, respectively). In conclusion, this study demonstrates that HBV disease progression is associated with viral escape mutations that are a marker of CTL activity. These data suggest that the number of non‐synonymous mutations in the HBV core region may predict HBV disease progression better than any single mutation or pattern of mutations. J. Med. Virol. 83:2082–2087, 2011. © 2011 Wiley Periodicals, Inc.     

Liver cell atypias: a comparative study in cirrhosis with and without hepatocellular carcinoma

Various criteria have been proposed for the identification of early neoplastic changes in the setting of both small hepatocellular carcinomas and macroregenerative nodules. In this study we have applied those criteria to cases of liver cirrhosis without tumour (group I) and hepatocellular-carcinoma-associated cirrhosis (group II) to assess their discriminatory value in these two situations. Group I included 50 liver biopsies with uncomplicated cirrhosis while group II encompassed 48 liver biopsies of cirrhotic nodules adjacent to hepatocellular carcinomas. The histological changes sought were large cell dysplasia, small cell dysplasia, cytoplasmic basophilia, small microacinar structures, peripheral distribution of nuclei, nuclear irregularities and thickened liver cell plates. These changes were also assessed in macroregenerative nodules (nine in group I and seven in group II). None of these changes was useful to discriminate between group I and group II cirrhotic nodules when assessed separately. On the other hand, cirrhotic nodules showing three or fewer changes were never associated with malignancy, whereas those exhibiting four or more alterations were often located in the vicinity of a tumour. Acinar structures, thickened cell trabeculae, peripheral distribution of nuclei and nuclear irregularities seem to be the most specific indicators of proximity to a hepatocellular carcinoma. Similar results were obtained for macroregenerative nodules. These results may be helpful as guidelines to the probability of having a hepatocellular carcinoma elsewhere in livers containing atypical cirrhotic nodules, and may also prove valuable in the selection of appropriate material for investigating early molecular events in hepatic carcinogenesis.     

CD10 is a diagnostic and prognostic marker in renal malignancies

AIMS: To determine the diagnostic and prognostic value of CD10 immunoreactivity in renal cell carcinomas (RCCs) and transitional cell carcinomas (TCCs). METHODS AND RESULTS: CD10 expression was investigated in primary (n = 180) and metastatic (n = 58) RCCs and upper urinary tract TCCs (n = 53) using a tissue microarray technique. One hundred and fifty-four of 172 (90%) evaluable primary and 48/56 (86%) evaluable metastatic RCCs expressed CD10. Extensive immunoreactivity (positivity of >50% cancer cells) decreased with rising tumour grade in conventional RCCs [G1/G2 72/81 (89%), G3/G4 33/48 (69%); P = 0.009]. Chromophobe RCCs showed a significantly lower overall and extensive immunoreactivity compared with conventional tumours (P < 0.001). In papillary RCCs immunoreactivity of more than 10% of cancer cells for CD10 was seen more often in type 2 (7/8, 88%) compared with type 1 (5/12, 42%; P =0.054) tumours. In conventional RCCs, pure apical membranous staining was associated with low tumour stage (P = 0.003), low grade (P = 0.004) and improved prognosis on univariate analysis (P = 0.031). TCCs were less frequently stained (51%). Extensive staining, however, was associated with high-stage tumours (P = 0.024), high-grade (P = 0.073) tumours, and was associated with shorter disease-free survival in univariate analysis (P = 0.003). CONCLUSIONS: CD10 proved to be an additional marker for renal malignancies with predominantly diagnostic potential.     

HAX-1 is overexpressed in hepatocellular carcinoma and promotes cell proliferation

Hepatocellular carcinoma (HCC) is the most common primary liver tumor. Due to the asymptomatic nature of early HCC and lack of effective screening strategies, 80% of patients present with advanced HCC at the time of diagnosis. Novel molecular marker identification will be valuable for effective diagnosis and treatment. In this study we reported HCLS1-associated protein X-1 (HAX-1) is overexpression in HCC in human HCC sample. Furthermore, we provided evidence that HAX-1 expression positively correlated with that of Ki67 in patient sample. Statistic analysis indicated that HAX-1 expression level significantly correlated with clinic outcome of HCC. Cell based assay revealed that knockdown of HAX-1 inhibits cell proliferation. This result suggests that HAX-1 can be a novel molecular marker for HCC.     

Oncostatin M receptor is a novel therapeutic target in cervical squamous cell carcinoma

Cervical carcinoma is the second most common cause of cancer deaths in women worldwide. Treatments have not changed for decades and survival rates for advanced disease remain low. An exciting new molecular target for the treatment of cervical squamous cell carcinoma (SCC), and possibly for SCCs at other anatomical sites, is the oncostatin M receptor (OSMR). This cell surface cytokine receptor is commonly copy number gained and overexpressed in advanced cervical SCC, changes that are associated with significantly worse clinical outcomes. OSMR overexpression in cervical SCC cells results in enhanced responsiveness to the major ligand oncostatin M (OSM), which induces several pro‐malignant effects, including a pro‐angiogenic phenotype and increased cell migration and invasiveness. OSMR is a strong candidate for antibody‐mediated inhibition, a strategy that has had a major impact on haematological malignancies and various solid tumours such as HER2‐positive breast cancers. © 2013 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.     

Glo1 genetic amplification as a potential therapeutic target in hepatocellular carcinoma

Glyoxalase 1 (Glo1) gene aberrations is associated with tumorigenesis and progression in numerous cancers. In this study, we explored the role of Glo1 genetic amplification and expression in Chinese patients with hepatocellular carcinoma (HCC), and Glo1 genetic amplification as potential therapeutic target for HCC. We used fluorescence in situ hybridization (FISH) analysis and qRT-PCR to examine Glo1 genetic aberrations and Glo1 mRNA expression in paired tumor samples obtained from HCC patients. Glo1 genetic amplification was identified in a subset of HCC patient (6%, 3/50), and up-regulation of Glo1 expression was found in 48% (24/50) of tumor tissues compared with adjacent non-tumorous tissues. Statistic analysis showed that Glo1-upregulation significantly correlated with high serum level of alpha-fetoprotein (AFP). Interfering Glo1 expression with shRNA knocking-down led to significant inhibition of cell growth and induced apoptosis in primarily cultured HCC cells carrying genetic amplified Glo1 gene, while no inhibitory effects on cell proliferation were observed in HCC cells with normal copies of Glo1 gene. Glo1 knockdown also inhibited tumor growth and induced apoptosis in xenograft tumors established from primarily cultured HCC cells with Glo1 gene amplification. In addition, Glo1 knocking-down with shRNA interfering caused cellular accumulation of methylglyoxal, a Glo1 cytotoxic substrate. Our data suggested Glo1 pathway activation is required for cell proliferation and cell survival of HCC cells carrying Glo1 genetic amplification. Intervention of Glo1 activation could be a potential therapeutic option for patients with HCC carrying Glo1 gene amplification.     

Functional degeneracy of residues in a T cell peptide epitope contributes to its recognition by different T cell hybridomas.

Synthetic antigen Poly EYK(EYA)5 induces T cells of narrowly defined fine specificity as represented by the two I-Ad-restricted T cell hybridomas, A.1.1 and B.1.1. Both these hybridomas recognize the minimum 15-amino-acid peptide sequence EYK(EYA)4. We have characterized the residues involved in the recognition of EYK(EYA)4 peptide by these hybridomas with synthetic peptides and discovered a distinct functional hierarchy for the residues in the sequence. Even with the repeating tripeptide (EYA)5, which is recognized by B.1.1 cells, the residues that are essential cluster near the middle of the sequence but not near the N- or C-terminal region. Different MHC binding and TCR contacting residues were found for each of the hybridomas. The results suggest that different T cells either recognize different parts of the peptide MHC complex or that the peptide binds to MHC in multiple conformations. This was supported by the fact that Poly EYK(EYA)5 is alpha-helical but the peptides used here showed only a slight propensity to adopt this structure and it did not correlate with their functional activity. We also found that (EYA)5 does not compete with EYK(EYA)4 in the stimulation of A.1.1 cells despite its obvious capacity to interact with I-Ad when it stimulates B.1.1 cells. This may be because these peptides have a low affinity for Ia and therefore only appropriate TCR interactions would stabilize the antigen-Ia complex. In conclusion, antigen-MHC-TCR interaction appears to be a dynamic process which allows recognition of different residues of a T cell determinant by different T cells.     

Mutants of the hepatitis B virus surface antigen that define some antigenically essential residues in the immunodominant a region

The nature of the immunodominant a region of hepatitis B virus surface antigen (HBsAg) has been examined by mutation of specific amino acid residues. Proline 142 was required for the exhibition of full antigenicity. Replacement of cysteines 124 and 147 by serines drastically reduced or eliminated reactivity with antibodies to HBsAg, which implicates these two residues in stabilising the conformation of the antigen. The a region of HBsAg has also been shown to influence both the immunoreactivity of the adjacent subtype antigenic region, despite being immunologically distinct from it, and the ability of the antigen to interact with a subtype-specific monoclonal antibody. These results emphasise the importance of the polypeptide region between cysteine residues 124 and 147 in determining a antigenicity, as well as manifestation of the subtype of HBsAg, and reinforce the view that these are conformational epitopes.     

E3B1/ABI-1 isoforms are down-regulated in cancers of human gastrointestinal tract

The expression of E3B1/ABI-1 protein and its role in cancer progression and prognosis are largely unknown in the majority of solid tumors. In this study, we examined the expression pattern of E3B1/ABI-1 protein in histologically confirmed cases of esophageal (squamous cell carcinoma and adenocarcinoma), gastro-esophageal junction, colorectal cancers and corresponding normal tissues freshly resected from a cohort of 135 patients, by Western Blotting and Immunofluorescence Staining. The protein is present in its phosphorylated form in cells and tissues. Depending on the extent of phosphorylation it is either present in hyper-phosphorylated (M. Wt. 72 kDa) form or in hypo-phosphorylated form (M. Wt. 68 kDa and 65 kDa). A thorough analysis revealed that expression of E3B1/ABI-1 protein is significantly decreased in esophageal, gastro-esophageal junction and colorectal carcinomas irrespective of age, gender, dietary and smoking habits of the patients. The decrease in expression of E3B1/ABI-1 was consistently observed for all the three isoforms. However, the decrease in the expression of isoforms varied with different forms of cancers. Down-regulation of E3B1/ABI-1 expression in human carcinomas may play a critical role in tumor progression and in determining disease prognosis.     

Loss of RhoGDI is a novel independent prognostic factor in hepatocellular carcinoma

RhoGDI (Rho GDP-dissociation inhibitor alpha or RhoGDIα) has been identified as a regulator of Rho GTPases, which are essential for tumor progression, but its role in cancer remains controversial and little is known in hepatocellular carcinoma (HCC). Using immunohistochemistry, we analyzed RhoGDI expression in 147 clinicopathologically characterized HCC cases. RhoGDI expression was detected in cytoplasm of HCC tissues. Statistical analysis showed that there was no relationship between RhoGDI expression and clinicopathological features. Importantly, a significant trend was identified between loss of RhoGDI expression in HCC and worsening clinical prognosis. Multivariate survival analysis showed that negative RhoGDI expression was recognized as an independent prognostic factor of patient’s survival. Our results suggest that RhoGDI protein is a valuable marker of prognosis for patients with HCC.     

Nonneoplastic signet-ring cell change in gastrointestinal and biliary tracts: a pitfall for overdiagnosis

Nonneoplastic signet-ring cell change (SRCC) is a rare but known phenomenon in gastrointestinal and biliary tracts and is always associated with underlying mucosal ulceration/erosion secondary to infection, ischemia, or other etiology. Because nonneoplastic SRCC closely mimics signet-ring cell adenocarcinoma (SRCA), differentiation of these 2 entities is critical because misdiagnosis of nonneoplastic SRCC as SRCA can lead to intense therapeutic interventions such as surgery and/or chemoradiation therapy. In this review, a brief overview on nonneoplastic SRCC in gastrointestinal and biliary tracts, including the spectrum of clinical presentation, important histologic features, and immunohistochemical markers that are useful in differentiating nonneoplastic SRCC from SRCA, is provided. The pathogenesis of nonneoplastic SRCC in gastrointestinal and biliary tracts is discussed.     

Meflin is a marker of pancreatic stellate cells involved in fibrosis and epithelial regeneration in the pancreas

Pancreatic stellate cells (PSCs) are stromal cells in the pancreas that play an important role in pancreatic pathology. In chronic pancreatitis (CP) and pancreatic ductal adenocarcinoma (PDAC), PSCs are known to get activated to form myofibroblasts or cancer-associated fibroblasts (CAFs) that promote stromal fibroinflammatory reactions. However, previous studies on PSCs were mainly based on the findings obtained using ex vivo expanded PSCs, with few studies that addressed the significance of in situ tissue-resident PSCs using animal models. Their contributions to fibrotic reactions in CP and PDAC are also lesser-known. These limitations in our understanding of PSC biology have been attributed to the lack of specific molecular markers of PSCs. Herein, we established Meflin (Islr), a glycosylphosphatidylinositol-anchored membrane protein, as a PSC-specific marker in both mouse and human by using human pancreatic tissue samples and Meflin reporter mice. Meflin-positive (Meflin⁺) cells contain lipid droplets and express the conventional PSC marker Desmin in normal mouse pancreas, with some cells also positive for Gli1, the marker of pancreatic tissue-resident fibroblasts. Three-dimensional analysis of the cleared pancreas of Meflin reporter mice showed that Meflin⁺ PSCs have long and thin cytoplasmic protrusions, and are localised on the abluminal side of vessels in the normal pancreas. Lineage tracing experiments revealed that Meflin⁺ PSCs constitute one of the origins of fibroblasts and CAFs in CP and PDAC, respectively. In these diseases, Meflin⁺ PSC-derived fibroblasts showed a distinctive morphology and distribution from Meflin⁺ PSCs in the normal pancreas. Furthermore, we showed that the genetic depletion of Meflin⁺ PSCs accelerated fibrosis and attenuated epithelial regeneration and stromal R-spondin 3 expression, thereby implying that Meflin⁺ PSCs and their lineage cells may support tissue recovery and Wnt/R-spondin signalling after pancreatic injury and PDAC development. Together, these data indicate that Meflin may be a marker specific to tissue-resident PSCs and useful for studying their biology in both health and disease. © 2023 The Pathological Society of Great Britain and Ireland.     

LOXL4 is downregulated in hepatocellular carcinoma with a favorable prognosis

Lysyl oxidase like 4 (LOXL4), a member of the secreted copper-dependent amine oxidases that contribute to the assemble and maintenance of the extracellular matrix (ECM), was found to be up-regulated or down-regulated in different cancer types, suggesting its paradoxical roles in cancer. The specific role of LOXL4 in hepatocellular carcinoma (HCC), however, is still yet to be defined. Twenty-eight pairs of HCC specimens were used for LOXL4 mRNA expression analysis. The mRNA expression in HCC cell lines was examined, and HepG2 was selected for LOXL4 small interfering RNA (siRNA) interference to investigate the biological function of LOXL4, LOXL4 immunohistochemical staining was performed using a tissue microarray containing 298 HCC patients. The prognostic and diagnostic value of LOXL4 was evaluated using Cox regression and Kaplan-Meier analysis. LOXL4 mRNA or protein expression was significantly lower in HCC tissues than peritumoral tissues (LOXL4 mRNA expression, P = 0.018; LOXL4 protein expression, P < 0.001). Low LOXL4 expression was associated with lower overall survival (OS) rates and higher cumulative recurrence rates. Multivariate analysis indicated that LOXL4 was an independent prognostic indicator for OS and time to recurrence (TTR). Our results revealed that LOXL4 was down-regulated in HCC and correlated with aggressive tumors and a worse clinical outcome. LOXL4 may be a potential biomarker to identify the HCC patients with a higher risk of recurrence.