Yohei Miyagi

Plasma Free Amino Acid Profiling of Five Types of Cancer Patients and Its Application for Early Detection

Background Recently, rapid advances have been made in metabolomics-based, easy-to-use early cancer detection methods using blood samples. Among metabolites, profiling of plasma free amino acids (PFAAs) is a promising approach because PFAAs link all organ systems and have important roles in metabolism. Furthermore, PFAA profiles are known to be influenced by specific diseases, including cancers. Therefore, the purpose of the present study was to determine the characteristics of the PFAA profiles in cancer patients and the possibility of using this information for early detection. Methods and Findings Plasma samples were collected from approximately 200 patients from multiple institutes, each diagnosed with one of the following five types of cancer: lung, gastric, colorectal, breast, or prostate cancer. Patients were compared to gender- and age- matched controls also used in this study. The PFAA levels were measured using high-performance liquid chromatography (HPLC)–electrospray ionization (ESI)–mass spectrometry (MS). Univariate analysis revealed significant differences in the PFAA profiles between the controls and the patients with any of the five types of cancer listed above, even those with asymptomatic early-stage disease. Furthermore, multivariate analysis clearly discriminated the cancer patients from the controls in terms of the area under the receiver-operator characteristics curve (AUC of ROC >0.75 for each cancer), regardless of cancer stage. Because this study was designed as case-control study, further investigations, including model construction and validation using cohorts with larger sample sizes, are necessary to determine the usefulness of PFAA profiling. Conclusions These findings suggest that PFAA profiling has great potential for improving cancer screening and diagnosis and understanding disease pathogenesis. PFAA profiles can also be used to determine various disease diagnoses from a single blood sample, which involves a relatively simple plasma assay and imposes a lower physical burden on subjects when compared to existing screening methods.

The Timing of GM-CSF Expression Plasmid Administration Influences the Th1/Th2 Response Induced by an HIV-1-Specific DNA Vaccine

The mechanism of immune activation induced by a plasmid-encoding GM-CSF (pGM-CSF), administered in combination with a DNA vaccine encoding the envelope of HIV, was studied. Injecting pGM-CSF i.m. into mice 3 days before DNA vaccination primarily induced a Th2 response. Simultaneous administration of the DNA vaccine plus pGM-CSF activated both a Th1 and a Th2 response. When the plasmid was injected 3 days after DNA vaccination, enhancement of Th1 immunity predominated. These results suggest that the timing of cytokine expression determines the phenotype of the resultant Th response. After 3 days of pGM-CSF injection, the increased percentages of CD11c+, CD8+ cells were observed in the regional lymph nodes. In addition, many infiltrated cells, including S-100 protein-positive cells, were found in the pGM-CSF-injected tissue. The importance of these S-100+ cells or both CD8+ and CD11c+ cells, especially that of dendritic cells (DCs), was also studied. DCs derived from bone marrow and cultured in RPMI 1640 medium containing IL-4 and GM-CSF were incubated with DNA vaccine and then transferred into naive mice. Mice receiving DCs showed strong HIV-1-specific Th2 immune responses. Our results suggest that DCs play important roles in the activation or modification of the Th2-type immune response induced by DNA vaccination.

Expression of Trypsin by Epithelial Cells of Various Tissues, Leukocytes, and Neurons in Human and Mouse

It has long been believed that trypsin is normally synthesized only in the pancreas. In the present study, expression of trypsin in human and mouse nonpancreatic tissues was examined. Northern blot analysis of normal human tissues indicated that the trypsin gene is expressed at high levels in the pancreas and spleen and considerably in the small intestine. However, in situ hybridization and immunohistochemistry demonstrated that trypsin is widely expressed in epithelial cells of the skin, esophagus, stomach, small intestine, lung, kidney, liver, and extrahepatic bile duct, as well as splenic and neuronal cells. In the spleen, trypsin message was detected in macrophages, monocytes, and lymphocytes in the white pulp. In the brain, it was detected in the nerve cells of the hippocampus and cerebral cortex. Analysis by gelatin zymography confirmed the presence of a latent or an active form of trypsin in various normal mouse tissues. Reverse transcription-polymerase chain reaction analysis also confirmed the expression of trypsin genes in the spleen, liver, kidney, and brain of normal mice. Such a broad distribution of trypsin suggests its general roles in the maintenance of normal epithelial cell functions, the immune defense system, and the central nervous system.

Dikkopf-1 as a Novel Serologic and Prognostic Biomarker for Lung and Esophageal Carcinomas

Gene expression profile analysis of lung and esophageal carcinomas revealed that Dikkopf-1 (DKK1) was highly transactivated in the great majority of lung cancers and esophageal squamous cell carcinomas (ESCC). Immunohistochemical staining using tumor tissue microarrays consisting of 279 archived non-small cell lung cancers (NSCLC) and 280 ESCC specimens showed that a high level of DKK1 expression was associated with poor prognosis of patients with NSCLC as well as ESCC, and multivariate analysis confirmed its independent prognostic value for NSCLC. In addition, we identified that exogenous expression of DKK1 increased the migratory activity of mammalian cells, suggesting that DKK1 may play a significant role in progression of human cancer. We established an ELISA system to measure serum levels of DKK1 and found that serum DKK1 levels were significantly higher in lung and esophageal cancer patients than in healthy controls. The proportion of the DKK1-positive cases was 126 of 180 (70.0%) NSCLC, 59 of 85 (69.4%) SCLC, and 51 of 81 (63.0%) ESCC patients, whereas only 10 of 207 (4.8%) healthy volunteers were falsely diagnosed as positive. A combined ELISA assays for both DKK1 and carcinoembryonic antigen increased sensitivity and classified 82.2% of the NSCLC patients as positive whereas only 7.7% of healthy volunteers were falsely diagnosed to be positive. The use of both DKK1 and ProGRP increased sensitivity to detect SCLCs up to 89.4%, whereas false-positive rate in healthy donors was only 6.3%. Our data imply that DKK1 should be useful as a novel diagnostic/prognostic biomarker in clinic and probably as a therapeutic target for lung and esophageal cancer.

Distinctive evaluation of nonmucinous and mucinous subtypes of bronchioloalveolar carcinomas in EGFR and K-ras gene-mutation analyses for Japanese lung adenocarcinomas: confirmation of the correlations with histologic subtypes and gene mutations.

Although adenocarcinomas of the lung are associated with epidermal growth factor receptor (EGFR) gene mutations and sensitivity to EGFR tyrosine kinase inhibitors, it remains unclear whether bronchioloalveolar carcinoma (BAC) components and/or subtypes affect these associations. We aimed to clarify correlations between EGFR gene mutations and BAC components and to establish the histologic features as reliable predictors for the mutations. We examined 141 non-small cell lung cancers (NSCLCs), including 118 adenocarcinomas, for mutations in exons 19 and 21 of the EGFR gene together with mutations in codon 12 of the K-ras gene using loop-hybrid mobility shift assays, a highly sensitive polymerase chain reaction-based method. Adenocarcinomas were subdivided into subtypes with a nonmucinous or mucinous BAC component and those without BAC components. In NSCLCs, EGFR mutations were detected in 75 cases (53.2%) and were significantly associated with adenocarcinoma, female sex, and never smoking. Among adenocarcinomas, nonmucinous and mucinous BAC components were significantly associated with EGFR and K-ras gene mutations, respectively. Because EGFR mutations were detected even in most pure nonmucinous BACs, ie, lung adenocarcinoma in situ, EGFR mutation is considered a critical event in the pathogenesis of nonmucinous BAC tumors.

Identification of Nectin-4 Oncoprotein as a Diagnostic and Therapeutic Target for Lung Cancer

Gene expression profile analysis of lung cancers revealed the transactivation of an immunoglobulin-like molecule Nectin-4 in the majority of non-small cell lung cancers (NSCLC). Immunohistochemical staining of 422 NSCLCs showed that a high level of Nectin-4 expression was associated with poor prognosis for NSCLC patients (P < 0.0001), and multivariate analysis confirmed its independent prognostic value (P < 0.0001). We established an ELISA to measure serum Nectin-4 and found that serum Nectin-4 levels were significantly higher in NSCLC patients than in healthy volunteers. The proportion of the serum Nectin-4-positive cases was 88 of 164 (53.7%) NSCLCs, whereas only 3 of 131 (2.3%) healthy volunteers were falsely diagnosed as positive, which was superior to carcinoembryonic antigen (CEA) and cytokeratin 19-fragment (CYFRA21-1) in sensitivity and specificity. A combined ELISA for both Nectin-4 and CEA increased sensitivity and classified 65.0% of lung adenocarcinomas as positive with false-positive rate of 4.6%. The use of both Nectin-4 and CYFRA21-1 classified 68.3% of lung squamous cell carcinomas as positive with false-positive rate of 6.1%. Treatment of lung cancer cells with small interfering RNAs against Nectin-4 suppressed its expression and cell growth. In addition, exogenous expression of Nectin-4 increased the lamellipodia formation and the invasive ability of mammalian cells through activation of small GTPase Rac1. Nectin-4 might play a significant role in lung carcinogenesis, and it should be a new candidate serum and tissue biomarker, as well as a therapeutic target.

Epigenetic inactivation of TFPI-2 as a common mechanism associated with growth and invasion of pancreatic ductal adenocarcinoma

Using microarrays, we have screened for genes reactivated by drugs that modify epigenetic mechanisms in pancreatic cancer cells. One of the genes identified was tissue factor pathway inhibitor 2 (TFPI-2), which encodes for a broad-spectrum serine proteinase inhibitor that negatively regulates the extracellular matrix degradation, an essential step in tumor invasion and metastasis. We therefore investigated the expression and methylation patterns of the TFPI-2 gene in pancreatic adenocarcinoma, and determined its role in tumor growth and invasion. In contrast to its abundant expression in normal pancreas, TFPI-2 mRNA was undetectable in a high fraction of pancreatic cancer cell lines and in primary pancreatic ductal neoplasms (IPMNs). Loss of TFPI-2 expression was associated with aberrant hypermethylation of its promoter CpG island. Treatment with the phorbol ester (PMA), known to stimulate the TFPI-2 promoter activity, augmented the TFPI-2 expression in cell lines with unmethylated or partially methylated TFPI-2, but failed to induce the expression in cell lines that harbored fully methylated TFPI-2. Aberrant methylation of TFPI-2 was also detected in 73% (102/140) of pancreatic cancer xenografts and primary pancreatic adenocarcinomas, was more likely in older patients with pancreatic cancer, and significantly correlated with progression of IPMNs (P=0.0002). Restored expression of the TFPI-2 gene in nonexpressing pancreatic cancer cells resulted in marked suppression in their proliferation, migration, and invasive potential in vitro. We thus conclude that epigenetic inactivation of TFPI-2 is a common mechanism that contributes to the aggressive phenotype of pancreatic ductal adenocarcinoma.

Interstitial pneumonia in Hermansky-Pudlak syndrome: significance of florid foamy swelling/degeneration (giant lamellar body degeneration) of type-2 pneumocytes

Abstract Although usual interstitial pneumonia (UIP)-like IP has been known as the most serious complication of Hermansky-Pudlak syndrome (HPS), its pathologic features and pathogenesis are poorly understood. We investigated biopsied and autopsied lung tissues from five patients who died of UIP-like IP associated with HPS (HPSIP). The salient histopathologic features of HPSIP observed were: (1) alveolar septa displaying florid proliferation of type-2 pneumocytes (2PCs) with characteristic foamy swelling/degeneration; (2) patchy fibrosis with lymphocytic and histiocytic infiltration centered around respiratory bronchioles, occasionally showing constrictive bronchiolitis; and (3) honeycomb change without predilection for the lower lobes or subpleural area. Those peculiar 2PCs were histochemically characterized by the over accumulation of phospholipid, immunohistochemically by a weak positivity for surfactant protein, and ultrastructurally by the presence of numerous giant lamellar bodies that compressed the nucleus with occasional cytoplasmic disruption, together suggesting a form of cellular degeneration with an over accumulation of surfactant (giant lamellar body degeneration). The present study strongly indicates that there is a basic defect in the formation/secretion process of surfactant by the 2PCs in HPS, which may well be the triggering factor for the HPSIP development. Other factors, such as macrophage dysfunction, may be working synergistically for further acceleration of the inflammatory process.

Negative effects of wild-type p53 and s-Myc on cellular growth and tumorigenicity of glioma cells

SummaryHuman (U251, U87, U343) and rat glioma cell lines (C6, 9L) were examined by the reverse transcriptase-polymerase chain reaction and subsequent nucleotide sequencing analysis to see whether they express wild type (wt)-p53 or mutated form (mut)-p53 messages. Results showed that U87, U343, and C6 cells expressed wt-p53 messages whereas U251 and 9L cells expressed mut-p53 messages. All these cell lines were transfected with wt-p53 cDNA or the s-myc gene linked to the mouse mammary tumor virus (MMTV) promoter. Of several G418-resistant clones obtained from each transfection, a few expressed the s-Myc or wt-p53 proteins. Independent of mutations in the intrinsic p53 gene, the cellular growthin vitro and tumorigenicity in nude mice of these clones were drastically suppressed, the extent of suppression being correlated with the expression level of the transfected gene. Flow-cytometric analysis demonstrated that both p53 and s-Myc arrested the cell cycle at the G1/S boundary. These data suggest that these genes having negative effects on tumor cell proliferation could be used in gene therapy of gliomas, which are caused by alteration of the p53 gene or by some other genetic change.

Wnt Inhibitor Dickkopf-1 as a Target for Passive Cancer Immunotherapy

Dickkopf-1 (DKK1) is an inhibitor of Wnt/beta-catenin signaling that is overexpressed in most lung and esophageal cancers. Here, we show its utility as a serum biomarker for a wide range of human cancers, and we offer evidence favoring the potential application of anti-DKK1 antibodies for cancer treatment. Using an original ELISA system, high levels of DKK1 protein were found in serologic samples from 906 patients with cancers of the pancreas, stomach, liver, bile duct, breast, and cervix, which also showed elevated expression levels of DKK1. Additionally, anti-DKK1 antibody inhibited the invasive activity and the growth of cancer cells in vitro and suppressed the growth of engrafted tumors in vivo. Tumor tissues treated with anti-DKK1 displayed significant fibrotic changes and a decrease in viable cancer cells without apparent toxicity in mice. Our findings suggest DKK1 as a serum biomarker for screening against a variety of cancers, and anti-DKK1 antibodies as potential theranostic tools for diagnosis and treatment of cancer.