Serum Proteins, HMMR, NXPH4, PITX1 and THBS4; A Panel of Biomarkers for Early Diagnosis of Hepatocellular Carcinoma.

The high morbidity rate of hepatocellular carcinoma (HCC) is mainly linked to late diagnosis. Early diagnosis of this leading cause of mortality is therefore extremely important. We designed a gene selection strategy to identify potential secretory proteins by predicting signal peptide cleavage sites in amino acid sequences derived from transcriptome data of human multistage HCC comprising chronic hepatitis, liver cirrhosis and early and overt HCCs. The gene selection process was validated by the detection of molecules in the serum of HCC patients. From the computational approaches, 10 gene elements were suggested as potent candidate secretory markers for detecting HCC patients. ELISA testing of serum showed that hyaluronan mediated motility receptor (HMMR), neurexophilin 4 (NXPH4), paired like homeodomain 1 (PITX1) and thrombospondin 4 (THBS4) are early-stage HCC diagnostic markers with superior predictive capability in a large cohort of HCC patients. In the assessment of differential diagnostic accuracy, receiver operating characteristic curve analyses showed that HMMR and THBS4 were superior to α-fetoprotein (AFP) in diagnosing HCC, as evidenced by the high area under the curve, sensitivity, specificity, accuracy and other values. In addition, comparative analysis of all four markers and AFP combinations demonstrated that HMMR-PITX1-AFP and HMMR-NXPH4-PITX1 trios were the optimal combinations for reaching 100% accuracy in HCC diagnosis. Serum proteins HMMR, NXPH4, PITX1 and THBS4 can complement measurement of AFP in diagnosing HCC and improve identification of patients with AFP-negative HCC as well as discriminate HCC from non-malignant chronic liver disease.

SMARCA4 oncogenic potential via IRAK1 enhancer to activate Gankyrin and AKR1B10 in liver cancer.

SWItch/Sucrose Non-Fermentable (SWI/SNF) is a multiprotein complex essential for the regulation of eukaryotic gene expression. SWI/SNF complex genes are genetically altered in over 20% of human malignancies, but the aberrant regulation of the SWI/SNF subunit genes and subsequent dysfunction caused by abnormal expression of subunit gene in cancer, remain poorly understood. Among the SWI/SNF subunit genes, SMARCA4, SMARCC1, and SMARCA2 were identified to be overexpressed in human hepatocellular carcinoma (HCC). Modulation of SMARCA4, SMARCC1, and SMARCA2 inhibited in vitro tumorigenesis of HCC cells. However, SMARCA4-targeting elicited remarkable inhibition in an in vivo Ras-transgenic mouse HCC model (Ras-Tg), and high expression levels of SMARCA4 significantly associated with poor prognosis in HCC patients. Furthermore, most HCC patients (72-86%) showed SMARCA4 overexpression compared to healthy controls. To identify SMARCA4-specific active enhancers, mapping, and analysis of chromatin state in liver cancer cells were performed. Integrative analysis of SMARCA4-regulated genes and active chromatin enhancers suggested 37 genes that are strongly activated by SMARCA4 in HCC. Through chromatin immunoprecipitation-qPCR and luciferase assays, we demonstrated that SMARCA4 activates Interleukin-1 receptor-associated kinase 1 (IRAK1) expression through IRAK1 active enhancer in HCC. We then showed that transcriptional activation of IRAK1 induces oncoprotein Gankyrin and aldo-keto reductase family 1 member B10 (AKR1B10) in HCC. The regulatory mechanism of the SMARCA4-IRAK1-Gankyrin, AKR1B10 axis was further demonstrated in HCC cells and in vivo Ras-Tg mice. Our results suggest that aberrant overexpression of SMARCA4 causes SWI/SNF to promote IRAK1 enhancer to activate oncoprotein Gankyrin and AKR1B10, thereby contributing to hepatocarcinogenesis.

Annual and seasonal patterns in etiologies of pediatric community-acquired pneumonia due to respiratory viruses and Mycoplasma pneumoniae requiring hospitalization in South Korea.

BACKGROUND: Community-acquired pneumonia (CAP) is one of the leading worldwide causes of childhood morbidity and mortality. Its disease burden varies by age and etiology and is time dependent. We aimed to investigate the annual and seasonal patterns in etiologies of pediatric CAP requiring hospitalization. METHODS: We conducted a retrospective study in 30,994 children (aged 0-18 years) with CAP between 2010 and 2015 at 23 nationwide hospitals in South Korea. Mycoplasma pneumoniae (MP) pneumonia was clinically classified as macrolide-sensitive MP, macrolide-less effective MP (MLEP), and macrolide-refractory MP (MRMP) based on fever duration after initiation of macrolide treatment, regardless of the results of in vitro macrolide sensitivity tests. RESULTS: MP and respiratory syncytial virus (RSV) were the two most commonly identified pathogens of CAP. With the two epidemics of MP pneumonia (2011 and 2015), the rates of clinical MLEP and MRMP pneumonia showed increasing trends of 36.4% of the total MP pneumonia. In children < 2 years of age, RSV (34.0%) was the most common cause of CAP, followed by MP (9.4%); however, MP was the most common cause of CAP in children aged 2-18 years of age (45.3%). Systemic corticosteroid was most commonly administered for MP pneumonia. The rate of hospitalization in intensive care units was the highest for RSV pneumonia, and ventilator care was most commonly needed in cases of adenovirus pneumonia. CONCLUSIONS: The present study provides fundamental data to establish public health policies to decrease the disease burden due to CAP and improve pediatric health.

Clinical characteristics and etiologies of bronchiectasis in Korean children: A multicenter retrospective study.

BACKGROUND: Bronchiectasis is a chronic pulmonary disease characterized by progressive and irreversible bronchial dilatation. The aim of the present study was to investigate the etiologies and clinical features of bronchiectasis in Korean children. METHODS: We performed a retrospective review of the medical records for children diagnosed with bronchiectasis between 2000 and 2017 at 28 secondary or tertiary hospitals in South Korea. RESULTS: A total of 387 cases were enrolled. The mean age at diagnosis was 9.2 ±â€¯5.1 years and 53.5% of the patients were boys. The most common underlying cause of bronchiectasis was preexisting respiratory infection (55.3%), post-infectious bronchiolitis obliterans (14.3%), pulmonary tuberculosis (12.3%), and heart diseases (5.6%). Common initial presenting symptoms included chronic cough (68.0%), recurrent pneumonia (36.4%), fever (31.1%), and dyspnea (19.7%). The most predominantly involved lesions were left lower lobe (53.9%), right lower lobe (47.1%) and right middle lobe (40.2%). No significant difference was observed in the distribution of these involved lesions by etiology. The forced expiratory volume in 1 s (FEV1) levels were lowest in cases with interstitial lung disease-associated bronchiectasis, followed by those with recurrent aspiration and primary immunodeficiency. CONCLUSIONS: Bronchiectasis should be strongly considered in children with chronic cough and recurrent pneumonia. Long-term follow-up studies on pediatric bronchiectasis are needed to further clarify the prognosis and reduce the disease burden in these patients.

Radiologic findings as a determinant and no effect of macrolide resistance on clinical course of Mycoplasma pneumoniae pneumonia.

BACKGROUND: With the emergence of macrolide resistance, concerns about the efficacy of macrolides for the treatment of Mycoplasma pneumoniae (MP) pneumonia in children have been raised. This study aimed to determine the effect of macrolide resistance on the outcome of children who were hospitalized with MP pneumonia. METHODS: Between 2010 and 2015, we performed culture of MP from nasopharyngeal samples obtained from children who were hospitalized with pneumonia at five hospitals in Korea. Macrolide resistance was determined by the analysis of 23S rRNA gene transition and the minimal inhibitory concentrations of four macrolides. Medical records were reviewed to analyze the clinical response to treatment with macrolides. RESULTS: MP was detected in 116 (4.8%) of the 2436 children with pneumonia. MP pneumonia was prevalent in 2011 and 2015. Of the 116 patients with MP pneumonia, 82 (70.7%) were macrolide-resistant. There were no differences in the age distribution, total duration of fever, and chest x-ray patterns between the macrolide-susceptible and macrolide-resistant groups. After macrolide initiation, mean days to defervescence were longer in the macrolide-resistant group than in macrolide-susceptible group (5.7 days vs. 4.1 days, P = 0.021). However, logistic regression analysis revealed that the presence of extrapulmonary signs (P = 0.039), homogeneous lobar consolidation (P = 0.004), or parapneumonic effusion (P < 0.001) were associated with fever duration of ≥7 days after the initiation of macrolides, regardless of macrolide resistance. CONCLUSIONS: This study demonstrated that fever duration in MP pneumonia was determined by the radiologic findings of chest x-ray, not by the presence of macrolide resistance. The results highlight the need for future studies to assess therapeutic benefit from macrolides in the treatment of children with MP pneumonia.

Oncogenic potential of histone-variant H2A.Z.1 and its regulatory role in cell cycle and epithelial-mesenchymal transition in liver cancer.

H2A.Z is a highly conserved H2A variant, and two distinct H2A.Z isoforms, H2A.Z.1 and H2A.Z.2, have been identified as products of two non-allelic genes, H2AFZ and H2AFV. H2A.Z has been reported to be overexpressed in breast, prostate and bladder cancers, but most studies did not clearly distinguish between isoforms. One recent study reported a unique role for the H2A.Z isoform H2A.Z.2 as a driver of malignant melanoma. Here we first report that H2A.Z.1 plays a pivotal role in the liver tumorigenesis by selectively regulating key molecules in cell cycle and epithelial-mesenchymal transition (EMT). H2AFZ expression was significantly overexpressed in a large cohort of hepatocellular carcinoma (HCC) patients, and high expression of H2AFZ was significantly associated with their poor prognosis. H2A.Z.1 overexpression was demonstrated in a subset of human HCC and cell lines. H2A.Z.1 knockdown suppressed HCC cell growth by transcriptional deregulation of cell cycle proteins and caused apoptotic cell death of HCC cells. We also observed that H2A.Z.1 knockdown reduced the metastatic potential of HCC cells by selectively modulating epithelial-mesenchymal transition regulatory proteins such as E-cadherin and fibronectin. In addition, H2A.Z.1 knockdown reduced the in vivo tumor growth rate in a mouse xenograft model. In conclusion, our findings suggest the oncogenic potential of H2A.Z.1 in liver tumorigenesis and that it plays established role in accelerating cell cycle transition and EMT during hepatocarcinogenesis. This makes H2A.Z.1 a promising target in liver cancer therapy.

Transglutaminase 2 expressed in mast cells recruited into skin or bone marrow induces the development of pediatric mastocytosis.

BACKGROUND: Mastocytosis is characterized by a pathological increase in mast cells in organs such as skin and bone marrow. Transglutaminase 2 (TG2) expressed in mast cells contributes to allergic diseases, but its role in mastocytosis has not been investigated. This study aimed to investigate whether TG2 contributes to pediatric mastocytosis. METHODS: Serum, various skin tissues or bone marrow (BM) biopsy and aspirates were obtained from pediatric normal control or patients with indolent systemic mastocytosis (SM), mastocytoma, and urticaria pigmentosa (UP). Tryptase, individual cytokines, leukotriene C4 (LTC4 ), and TG2 activity in the serum were determined by enzyme-linked immunosorbent assay, mast cell population by May-Grünwald-Giemsa, CD 117 by immunofluorescence, cell surface molecules by Western blot, and colocalization of c-kit and TG2 or IL-10-expressing cells, CD25, and FOXP3 by immunohistochemistry. RESULTS: Infiltration of CD25(+) CD117(+) CD2(-) mast cells into BM and scalp/trunk/ear dermis; expression of FcεRI, tryptase, c-kit, FOXP3, CCL2/CCR2, and vascular cell adhesion molecule-1; and colocalization of c-kit and TG2 were enhanced in patient's skin tissues or BM, particularly SM, but colocalization of c-kit and IL-10-expressing cells was decreased vs. normal tissues. Amounts of LTC4 and inflammatory cytokines, expression of tryptase or TG2 activity were increased in patient's serum, BM aspirates, or ear/scalp skin tissues, respectively, vs. normal persons, but IL-10 level was decreased. CONCLUSION: The data suggest that mast cells, recruited in the skin and BM by CCL2/CCR, may induce the development of pediatric mastocytosis through reducing IL-10 due to upregulating TG2 activity via transcription factor nuclear factor-κB. Thus, TG2 may be used in diagnosis of pediatric mastocytosis, particularly SM.

Characteristic molecular signatures of early exposure to volatile organic compounds in rat liver.

OBJECTIVE: Investigation on whether the characteristic molecular signatures can discriminate individual volatile organic compounds (VOCs) and provide predictive markers for the detection of VOC exposure. METHODS: Transcriptomic analysis of liver tissues was performed 48 h after the single oral administration of three VOCs doses at LD25 or LD5 values, to Sprague-Dawley. RESULTS: Combination analysis of different multi-classifications suggested that 145 genes predicted VOC exposure. Additionally, Gene Set Enrichment Analysis of genes deregulated by VOCs revealed that T cell prolymphatic leukemia signaling was inactivated in all VOCs. CONCLUSIONS: These molecular markers could be widely implemented to assess and predict environmental exposure to VOCs.

DBC1 does not function as a negative regulator of SIRT1 in liver cancer.

The putative tumor suppressor, DBC1 (deleted in breast cancer-1), was recently found to negatively regulate SIRT1 in vitro and in vivo, but the mechanism whereby DBC1 regulates SIRT1 in liver cancer remains to be elucidated. In this study, it was found that although the expression of DBC1 and SIRT1 was not aberrantly regulated in a large cohort of human hepatocellular carcinoma (HCC) patients, these proteins were highly overexpressed in a subset of HCC tissues compared with surrounding non-cancer tissues. In liver cancer, DBC1 and SIRT1 were found to be positively correlated. Inactivation of DBC1 or SIRT1 reduced SNU-182 (a liver cancer cell line) proliferation as determined by MTT viability assays. Notably, although DBC1 functions as a negative regulator of SIRT1 in A549 lung cancer cells since it suppresses the deacetylase activity of the p53 protein, it did not affect the p53 deacetylase activity of SIRT1 in SNU-182 cells. Taken together, we conclude that DBC1 is associated with SIRT1 in HCC, but that it does not inhibit SIRT1.

Platycodon grandiflorum modifies adipokines and the glucose uptake in high-fat diet in mice and L6 muscle cells.

OBJECTIVES: Obesity and diabetes have become the most common human health problems worldwide. Obesity's contribution to type 2 diabetes might be due to dysregulation of adipokines and glucose uptake. METHODS: In this study, we performed in-vivo and in-vitro studies to evaluate the effects of Platycodon grandiflorum extract (PGE) on adipokines and glucose uptake. Before study, platycodin D concentrations were analysed by HPLC in PGE prepared in water, in 50% ethanol and in 80% ethanol, and we selected the 80% ethanol extract as the PGE for this study based on the HPLC results. KEY FINDINGS: We found that inclusion of PGE in the high-fat diet (HFD) markedly attenuated food intake, body weight, epididymal fat weight, adipocyte size and blood glucose levels by the oral glucose tolerance test in mice, and maintained serum levels of adiponectin, resistin, leptin, fructosamine and triglycerides. Gene expression analysis revealed that PGE up-regulated adiponectin, and down-regulated TNF-α and leptin in fat tissue. In L6 muscle cells in vitro, PGE increased insulin-stimulated glucose uptake. CONCLUSIONS: We conclude that PGE may improve obesity in mice fed an HFD and glucose uptake in L6 muscle cells by modifying adipokines, and could offer clinical benefits as a supplement to treat obesity and diabetes.

Treatment of obstructive sleep apnea in children.

Obstructive sleep apnea (OSA) in children is a frequent disease for which optimal diagnostic methods are still being defined. Treatment of OSA in children should include providing space, improving craniofacial growth, resolving all symptoms, and preventing the development of the disease in the adult years. Adenotonsillectomy (T&A) has been the treatment of choice and thought to solve young patient's OSA problem, which is not the case for most adults. Recent reports showed success rates that vary from 27.2% to 82.9%. Children snoring regularly generally have a narrow maxilla compared to children who do not snore. The impairment of nasal breathing with increased nasal resistance has a well-documented negative impact on early childhood maxilla-mandibular development, making the upper airway smaller and might lead to adult OSA. Surgery in young children should be performed as early as possible to prevent the resulting morphologic changes and neurobehavioral, cardiovascular, endocrine, and metabolic complications. Close postoperative follow-up to monitor for residual disease is equally important. As the proportion of obese children has been increasing recently, parents should be informed about the weight gain after T&A. Multidisciplinary evaluation of the anatomic abnormalities in children with OSA leads to better overall treatment outcome.

Targeted disruption of Nemo-like kinase inhibits tumor cell growth by simultaneous suppression of cyclin D1 and CDK2 in human hepatocellular carcinoma.

The Wnt/beta-catenin signaling pathway regulates various aspects of development and plays important role in human carcinogenesis. Nemo-like kinase (NLK), which is mediator of Wnt/beta-catenin signaling pathway, phosphorylates T-cell factor/lymphoid enhancer factor (TCF/LEF) factor and inhibits interaction of beta-catenin/TCF complex. Although, NLK is known to be a tumor suppressor in Wnt/beta-catenin signaling pathway of colon cancer, the other events occurring downstream of NLK pathways in other types of cancer remain unclear. In the present study, we identified that expression of NLK was significantly up-regulated in the HCCs compared to corresponding normal tissues in five selected tissue samples. Immunohistochemical analysis showed significant over-expression of NLK in the HCCs. Targeted-disruption of NLK suppressed cell growth and arrested cell cycle transition. Suppression of NLK elicited anti-mitogenic properties of the Hep3B cells by simultaneous inhibition of cyclinD1 and CDK2. The results of this study suggest that NLK is aberrantly regulated in HCC, which might contribute to the mitogenic potential of tumor cells during the initiation and progression of hepatocellular carcinoma; this process appears to involve the induction of CDK2 and cyclin D1 and might provide a novel target for therapeutic intervention in patients with liver cancer.

Targeted disruption of S100P suppresses tumor cell growth by down-regulation of cyclin D1 and CDK2 in human hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is the third leading cause of cancer death worldwide. The number of cases of HCC has continued to increase in recent decades. Previous studies have suggested that S100P, a member of the S100P calcium-binding protein family, is aberrantly regulated in several malignant neoplasms. However, the underlying molecular mechanisms of the dysregulation of S100P remain to be elucidated. To investigate biological effects of S100P on hepatocarcinogenesis, aberrant expression of S100P was investigated by immunohistochemistry (IHC), Western blot analysis and reverse transcriptase-polymerase chain reaction (RT-PCR) in HCC tissues and cell lines. Endogenous expression of S100P was disrupted by the RNA interference-mediated protein knockdown method in the human Hep3B liver cancer cell line. Then, cell growth and cellular apoptosis were compared with control siRNA transfectants. The effects of S100P-silencing on the major components of cell cycle regulation were assessed by Western blot analysis. As results, elevated levels of S100P were observed in the HCC tissues compared to the corresponding normal tissues. Targeted disruption of S100P suppressed cell growth and augmented cellular apoptosis. In addition, inhibition of S100P resulted in the down-regulation of cyclinD1 and CDK2. In conclusion, this study showed over-expression of S100P in HCC. The aberrant regulation of S100P in HCC might activate cyclin D1 and CDK expression and contribute to the mitogenic potential of tumor cells during HCC carcinogenesis. These findings provide information that suggests new therapeutic strategies for the treatment of liver cancer.

Systemic cell-cycle suppression by Apicidin, a histone deacetylase inhibitor, in MDA-MB-435 cells.

Histone deacetylase (HDAC) inhibitors are emerging as an exciting new class of potential anti-cancer agents for the treatment of solid and hematological malignancies. However, the best characterized HDAC function concerns the control of gene expression via the regulation of transcription activation or repression. To understand the genome-wide effects of HDAC inhibition on gene regulation, we performed serial gene expression analyses from 0 to 48 h after treating MDA-MB-435, a melanoma-derived highly metastatic tumor cell line, with Apicidin, a HDAC inhibitor. Combined-transcriptomic analysis of large-scale molecular changes induced by Apicidin resulted in the identification of 631 outlier genes that were continuously up- or down-regulated during the 48 h study period. When the 631 outlier genes were mapped to known biological processes, cell-cycle suppression emerged as the function most elicited by Apicidin. In addition comprehensive negative cell-cycle regulation by Apicidin was dissected using gene expression data and validated by Western blot analysis. We suggest the 631 outlier genes as a characteristic molecular signature for Apicidin, and propose concurrent transcriptional suppression of major components of cell-cycle regulatory circuit as potent anti-tumor mechanism of Apicidin. Genetic elements identified during this study also provide the possibility of novel therapeutic interventions in tumor metastasis.

An alternative therapy for graves' disease: clinical effects and mechanisms of an herbal remedy.

Graves' disease, the most common cause of hyperthyroidism, is an autoimmune disorder. Antithyroid drugs have been selected as the first-line treatment of Graves' disease in Korea, Japan, and European countries. However, antithyroid drugs such as methimazole (MMI) and prophylthiouracil (PTU) have limitations in clinical applications because of their side effects. In this study, we performed a clinical trial and in vitro study to investigate the clinical effects and action mechanism of Ahnjeonbaekho-tang (AJBHT), an herbal remedy for Graves' disease. In a clinical study of Graves' disease patients who had side effects from antithyroid drugs, we found that treatment by AJBHT resulted in a reduction of serum triiodothyronine (T3) and free thyroxine (FT4) levels and an increase in thyroid stimulating hormone (TSH) levels (T3: p<0.0001, FT4: p=0.0012, TSH: p=0.0370, respectively). In vitro, AJBHT significantly inhibits FRTL-5 cell proliferation, DNA synthesis, cyclic AMP production, T4 synthesis, and the expression of thyroglobulin (Tg) mRNA in comparison with the control. These results suggest that AJBHT might suppress T(4) synthesis by modulating adenosine 3',5'-cyclic monophosphate (cAMP) and Tg expression, and therefore, AJBHT could be an alternative therapy for Graves' disease patients who have side effects from antithyroid drugs.

Identification of large-scale molecular changes of Autotaxin(ENPP2) knock-down by small interfering RNA in breast cancer cells.

To understand comprehensive molecular mechanisms by which Autotaxin (ENPP2) mediates, we identified large-scale molecular changes responsible for aberrant expression of Autotaxin (ATX) on breast cancer cells by using DNA microarrays. Transcriptional over-expression of ENPP2 gene was endogenously silenced by using RNA interference technique, and then recapitulated corresponding molecular changes in MDA435 breast cancer cells. Application of nonparametric Wilcoxon statistical analyses (P<0.05) and the selection criteria of 2-fold differential gene expression change resulted in the identification of 368 genes including 133 up-regulated and 235 genes under-expressed in ENPP2-silencing MDA435 cells. Most of the functional categories of identified genes are associated with cellular metabolism, cytoskeleton organization, transcription regulation, signal transduction as well as cellular organization and biogenesis. Our data suggest that the molecular signature identified by the ENPP2-silencing methods may represent potential candidates that can explain the complicated characteristics of ATX and may serve as biomarkers, for the development of molecular-targeting therapy, in human breast cancer.

Comparative analysis of expression profiling of early-stage carcinogenesis using nodule-in-nodule-type hepatocellular carcinoma.

BACKGROUND: Nodule-in-nodule-type hepatocellular carcinoma (NIN-HCC) is a useful model to illustrate the multi-step nature of hepatocarcinogenesis. To identify large-scale molecular change in early hepatocarcinogenesis, the expression profile of NIN-HCC was compared with those from three sets of individual high-grade dysplastic nodules (HGDN) and grade 1 hepatocellular carcinomas. METHODS: We compared expression profiles of inner grade 1 hepatocellular carcinoma nodules and peripheral HGDN in one case of NIN-HCC using spotted-oligonucleotide DNA microarray. The relevant outlier genes assumed to associate with early carcinogenesis in hepatocellular carcinoma were identified by comparative analysis of NIN-HCC and individual cases of HGDN and grade 1 hepatocellular carcinoma, respectively. RESULTS: From this analysis we extracted a total of 40 genes, consisting of 28 up-regulated genes and 12 downregulated genes, and more than a two-fold change in grade 1 hepatocellular carcinoma compared with HGDN. CONCLUSION: We assessed the expression profiles of pre-neoplastic lesions and grade 1 hepatocellular carcinoma using oligonucleotide microarray analysis and found high stringent outlier genes that are presumably directly involved in the transition from dysplastic nodule to the early stage of hepatocellular carcinoma by utilizing NIN-HCC.

Autotaxin (lysoPLD/NPP2) protects fibroblasts from apoptosis through its enzymatic product, lysophosphatidic acid, utilizing albumin-bound substrate.

Autotaxin (ATX) was originally identified as a potent tumor cell motility-stimulating factor that displays multiple enzymatic activities including ATPase, Type I nucleotide pyrophosphatase/phosphodiesterase, and lysophospholipase D, depending on its substrates. We demonstrate herein that ATX is a key regulator of extracellular lysophosphatidic acid (LPA) that can act as survival factor, in addition to its mitogenic activity in mouse fibroblasts. Introduction of atx gene into NIH3T3 cells resulted in resistance to conditional apoptosis induced by serum-deprivation, and exogenous ATX protein prevented cells from death by starvation. Flow cytometric analysis showed that co-treatment of ATX with lysophosphatidylcholine as substrate rescued NIH3T3 cells from cellular apoptosis, and this survival activity of ATX was also demonstrated by caspase-3 degradation and PARP cleavage resulting from the enzymatic activity of extracellular ATX. Furthermore, the effect of ATX in preventing apoptosis appears to be mediated through the G-protein-coupled receptor pathway followed by the activation of phosphoinositide 3-kinase and Akt pathway leading to enhanced cell survival. These findings provide novel insights into understanding the functions of ATX as a key regulator of bioactive phospholipids and suggest interventions to correct dysfunction in conditions of tumor cell growth and metastasis.

Increased expression of histone deacetylase 2 is found in human gastric cancer.

Accumulated evidence has established that aberrant regulation of histone deacetylases (HDACs) is one of the major causes of the development of human malignancies. Among different iso-enzymes of HDAC and sirtuins grouped as the HDAC super family, little is known as to how histone deacetylase 2 (HDAC2) causes carcinogenesis in solid tumors. Here, in order to investigate the possible role of HDAC2 in gastric carcinogenesis, we analyzed the expression of HDAC2 in 71 gastric adenocarcinomas by immunohistochemistry. Moderate to strong expression of HDAC2 was found in 44 (62%) out of a total of 71 tumors. The majority of positive tumors, which were detected in the nucleus but not in normal gastric epithelium, did not express HDAC2 or showed only weak positive staining. Interestingly, we also noted that HDAC2 expression appeared to be associated with tumor aggressiveness as HDAC2 expression was observed to be statistically significant in advanced gastric cancer (P=0.0023, Chi-square test) and in positive lymph node metastasis (P=0.0713, Chi-square test). Taken together, these results suggest that HDAC2 may play an important role in the aggressiveness of gastric cancer.

Genetic alterations of the HCCS1 gene in Korean hepatocellular carcinoma.

We analyzed the gene mutations and loss of heterozygosity (LOH) of the HCCS1 gene using intragenic polymorphic markers in a series of 88 primary HCCs. We found two sequence variations at exon 5 and 14 in both normal and tumor DNAs of case 50 and 51, respectively. The variation in case 50 led to a reading frameshift and a premature stop (TGA) at codon 125 and case 51 showed amino acid change at codon 448 (Val-->Ala, GTG-->GCG). Interestingly, these variations were not found in peripheral lymphocytes of 69 normal individuals and 227 cancer patients (86 HCC, 75 unselected gastric cancer, and 66 breast cancer), suggesting that these two variations are mutation, not polymorphism. In addition, we found 14 novel intragenic polymorphic sites in the HCCS1 gene. Thirty-two (47%) of sixty-eight informative cases showed allelic loss at at least one or more intragenic polymorphic sites, but there was no significant relationship between the frequency of LOH and clinicopathologic parameters. These results suggest that mutation of the HCCS1 gene might not be a main inactivation mechanism in the development of Korean HCC and that the HCCS1 gene might be involved in acceleration of the tumorigenic process in Korean HCC.