Chia-Tung Shun

Isolation of multipotent cells from human term placenta.

Current sources of stem cells include embryonic stem cells (ESCs) and adult stem cells (ASCs). However, concerns exist with either source: ESCs, with their significant ethical considerations, tumorigenicity, and paucity of cell lines; and ASCs, which are possibly more limited in potential. Thus, the search continues for an ethically conducive, easily accessible, and high‐yielding source of stem cells. We have isolated a population of multipotent cells from the human term placenta, a temporary organ with fetal contributions that is discarded postpartum. These placenta‐derived multipotent cells (PDMCs) exhibit many markers common to mesenchymal stem cells—including CD105/endoglin/SH‐2, SH‐3, and SH‐4—and they lack hematopoietic‐, endothelial‐, and trophoblastic‐specific cell markers. In addition, PDMCs exhibit ESC surface markers of SSEA‐4, TRA‐1‐61, and TRA‐1‐80. Adipogenic, osteogenic, and neurogenic differentiation were achieved after culturing under the appropriate conditions. PDMCs could provide an ethically uncontroversial and easily accessible source of multipotent cells for future experimental and clinical applications.

A Novel Virulence Gene in Klebsiella pneumoniae Strains Causing Primary Liver Abscess and Septic Metastatic Complications

Primary Klebsiella pneumoniae liver abscess complicated with metastatic meningitis or endophthalmitis is a globally emerging infectious disease. Its pathogenic mechanism remains unclear. The bacterial virulence factors were explored by comparing clinical isolates. Differences in mucoviscosity were observed between strains that caused primary liver abscess (invasive) and those that did not (noninvasive). Hypermucoviscosity correlated with a high serum resistance and was more prevalent in invasive strains (52/53 vs. 9/52; P < 0.0001). Transposon mutagenesis identified candidate virulence genes. A novel 1.2-kb locus, magA, which encoded a 43-kD outer membrane protein, was significantly more prevalent in invasive strains (52/53 vs. 14/52; P < 0.0001). The wild-type strain produced a mucoviscous exopolysaccharide web, actively proliferated in nonimmune human serum, resisted phagocytosis, and caused liver microabscess and meningitis in mice. However, magA − mutants lost the exopolysaccharide web and became extremely serum sensitive, phagocytosis susceptible, and avirulent to mice. Virulence was restored by complementation using a magA-containing plasmid. We conclude that magA fits molecular Kochs postulates as a virulence gene. Thus, this locus can be used as a marker for the rapid diagnosis and for tracing the source of this emerging infectious disease.

A prospective comparative study of narrow-band imaging, chromoendoscopy, and conventional colonoscopy in the diagnosis of colorectal neoplasia

Background: Discrimination between neoplastic and non-neoplastic lesions is crucial in colorectal cancer screening. Application of narrow-band imaging (NBI) in colonoscopy visualises mucosal vascular networks in neoplastic lesions and may improve diagnostic accuracy. Aim: To compare the diagnostic efficacy of NBI in differentiating neoplastic from non-neoplastic colorectal lesions with diagnostic efficacies of standard modalities, conventional colonoscopy, and chromoendoscopy. Methods: In this prospective study, 180 colorectal lesions from 133 patients were observed with conventional colonoscopy, and under low-magnification and high-magnification NBI and chromoendoscopy. Lesions were resected for histopathological analysis. Endoscopic images were stored electronically and randomly allocated to two readers for evaluation. Sensitivity, specificity and diagnostic accuracy of each endoscopic modality were assessed by reference to histopathology. Results: NBI and chromoendoscopy scored better under high magnification than under low magnification in comparison with conventional colonoscopy. The diagnostic accuracy of NBI with low or high magnification was significantly higher than that of conventional colonoscopy (low magnification: p = 0.0434 for reader 1 and p = 0.004 for reader 2; high magnification: p<0.001 for both readers) and was comparable to that of chromoendoscopy. Conclusion: Both low-magnification and high-magnification NBI were capable of distinguishing neoplastic from non-neoplastic colorectal lesions; the diagnostic accuracy of NBI was better than that of conventional colonoscopy and equivalent to that of chromoendoscopy. The role of NBI in screening colonoscopy needs further evaluation.

Specific EGFR Mutations Predict Treatment Outcome of Stage IIIB/IV Patients With Chemotherapy-Naive Non–Small-Cell Lung Cancer Receiving First-Line Gefitinib Monotherapy

PURPOSE To explore predictive factors for time to treatment failure (TTF) in chemotherapy-naive non-small-cell lung cancer (NSCLC) patients receiving gefitinib treatment. PATIENTS AND METHODS We designed a phase II study to test gefitinib antitumor efficacy in advanced-stage, chemotherapy-naive NSCLC patients. Patients were treated with gefitinib 250 mg/d. Tumor assessments were performed every 2 months. Responding or stable patients were treated until progression or unacceptable toxicity. All scans were reviewed independently. EGFR exons 18-21 sequence, K-ras exon 2 sequence, and MET gene copy numbers were examined in available samples. Clinical or molecular predictors of TTF were examined by multivariate analysis. RESULTS One hundred six patients were enrolled. Ninety patients had tumor samples for biomarker tests. Overall response rate was 50.9% (95% CI, 41.4% to 60.4%). Median TTF was 5.5 months, and median overall survival (OS) was 22.4 months. The response rate and median TTF of the patients with exon 19 deletion (n = 20) were 95.0% and 8.9 months, for exon 21 L858R mutation (n = 23) were 73.9% and 9.1 month, and for other types of EGFR mutations (N = 12) were 16.7% and 2.3 months, respectively. In multivariate analysis, the presence of EGFR deletion exon 19 or L858R EGFR mutations in adenocarcinoma patients predicted longer TTF. High copy number of MET seemed to correlate with shorter TTF in patients with gefitinib-sensitive activating EGFR mutations. CONCLUSION In this prospective study, EGFR exon 19 deletion or L858R mutations in adenocarcinoma were the best predictors for longer TTF in stage IIIB/IV chemotherapy-naive NSCLC patients receiving first-line gefitinib monotherapy.

Tumor-Associated Macrophage-Induced Invasion and Angiogenesis of Human Basal Cell Carcinoma Cells by Cyclooxygenase-2 Induction

Tumor-associated macrophages (TAMs) and cyclooxygenase-2 (COX-2) are associated with invasion, angiogenesis, and poor prognosis in many human cancers. However, the role of TAMs in human basal cell carcinoma (BCC) remains elusive. We found that the number of TAMs infiltrating the tumor is correlated with the depth of invasion, microvessel density, and COX-2 expression in human BCC cells. TAMs also aggregate near COX-2 expressing BCC tumor nests. We hypothesize that TAMs might activate COX-2 in BCC cells and subsequently increase their invasion and angiogenesis. TAMs are a kind of M2 macrophage derived from macrophages exposed to Th2 cytokines. M2-polarized macrophages derived from peripheral blood monocytes were cocultured with BCC cells without direct contact. Coculture with the M2 macrophages induced COX-2-dependent invasion and angiogenesis of BCC cells. Human THP-1 cell line cells, after treated with phorbol myristate acetate (PMA), differentiated to macrophages with M2 functional profiles. Coculture with PMA-treated THP-1 macrophages induced COX-2-dependent release of matrix metalloproteinase-9 and subsequent increased invasion of BCC cells. Macrophages also induced COX-2-dependent secretion of basic fibroblast growth factor and vascular endothelial growth factor-A, and increased angiogenesis in BCC cells.

Interleukin-10 genotypes associate with the risk of gastric carcinoma in Taiwanese Chinese.

The association of cytokine genotypes with gastric carcinoma (GC) may be influenced by environmental factors and varies among different populations. Few studies have addressed the impact of different cytokine genotypes on the development and progression of GC. We analyzed 11 functional polymorphisms in tumor necrosis factor‐α (TNF‐α), interleukin (IL)‐1, IL‐4 and IL‐10 genes in 220 Taiwanese Chinese with GC and in 230 healthy controls. The risk of genotypes was adjusted with confounding environmental risks. Our results revealed that the frequency of Helicobacter pylori infection [odds ratio (OR) 1.7, 95% confidence interval (CI) 1.19–2.56], cigarette smoking (OR 2.02, 95% CI 1.38–2.95) and high IL‐10 producer genotype (OR 2.67, 95% CI 1.29–5.50) was significantly increased in the entire GC patients. Among different subtypes of GC, a higher risk of developing diffuse type (OR 1.64, 95% CI 1.01–2.67) or cardia cancer (OR 2.44, 95% CI 1.13–2.67) was observed for the CT/CC genotype of IL‐4 at the position −590, whereas the high IL‐10 producer genotype was significantly linked with the risk of cardia cancer (OR 3.21, 95% CI 1.06–9.73) or advanced stage (OR 2.29, 95% CI 1.12–4.64). No association was noted between GC and controls in the distribution of IL‐1 and TNF‐α genotypes. Logistic regression analyses revealed that H. pylori infection (OR 1.7, 95% CI 1.14–2.52), cigarette smoking (OR 1.87, 95% CI 1.27–‐2.96) and IL‐10 genotype (OR 2.54, 95% CI 1.24–5.61) are independent risks for GC. Independent effects of IL‐10 genotype, H. pylori infection and cigarette smoking indicate that carcinogenesis of GC is influenced by a variety of host and environmental factors.

Sequential versus triple therapy for the first-line treatment of Helicobacter pylori: a multicentre, open-label, randomised trial

BACKGROUND Whether sequential treatment can replace triple therapy as the standard treatment for Helicobacter pylori infection is unknown. We compared the efficacy of sequential treatment for 10 days and 14 days with triple therapy for 14 days in first-line treatment. METHODS For this multicentre, open-label, randomised trial, we recruited patients (≥20 years of age) with H pylori infection from six centres in Taiwan. Using a computer-generated randomisation sequence, we randomly allocated patients (1:1:1; block sizes of six) to either sequential treatment (lansoprazole 30 mg and amoxicillin 1 g for the first 7 days, followed by lansoprazole 30 mg, clarithromycin 500 mg, and metronidazole 500 mg for another 7 days; with all drugs given twice daily) for either 10 days (S-10) or 14 days (S-14), of 14 days of triple therapy (T-14; lansoprazole 30 mg, amoxicillin 1 g, and clarithromycin 500 mg for 14 days; with all drugs given twice daily). Investigators were masked to treatment allocation. Our primary outcome was the eradication rate in first-line treatment by intention-to-treat (ITT) and per-protocol (PP) analyses. This trial is registered with ClinicalTrials.gov, number NCT01042184. FINDINGS Between Dec 28, 2009, and Sept 24, 2011, we enrolled 900 patients: 300 to each group. The eradication rate was 90·7% (95% CI 87·4-94·0; 272 of 300 patients) in the S-14 group, 87·0% (83·2-90·8; 261 of 300 patients) in the S-10 group, and 82·3% (78·0-86·6; 247 of 300 patients) in the T-14 group. Treatment efficacy was better in the S-14 group than it was in the T-14 group in both the ITT analysis (number needed to treat of 12·0 [95% CI 7·2-34·5]; p=0·003) and PP analyses (13·7 [8·3-40], p=0·003). We recorded no significant difference in the occurrence of adverse effects or in compliance between the three groups. INTERPRETATION Our findings lend support to the use of sequential treatment as the standard first-line treatment for H pylori infection. FUNDING National Taiwan University Hospital and National Science Council.

The benefit of mass eradication of Helicobacter pylori infection: a community-based study of gastric cancer prevention

Objective To evaluate the benefit of mass eradication of Helicobacter pylori infection in reducing premalignant gastric lesions. Design Mass eradication of H pylori infection was started from 2004 for a Taiwanese population with prevalent H pylori infection, who were >30 years of age. Participants positive for the 13C-urea breath test underwent endoscopic screening and 1-week clarithromycin-based triple therapy. For subjects whose initial treatment failed, 10-day levofloxacin-based triple therapy was administered. The main outcome measures were changes in the prevalence of H pylori infection and premalignant gastric lesions, and changes in the incidence of premalignant gastric lesions and gastric cancer before (1995–2003) and after (2004–2008) chemoprevention using various comparators. Results The reduction in H pylori infection was 78.7% (95% CI 76.8% to 80.7%), and the estimated incidence of re-infection/recrudescence was 1% (95% CI 0.6% to 1.4%) per person-year. The effectiveness of reducing the incidence of gastric atrophy resulting from chemoprevention was significant at 77.2% (95% CI 72.3% to 81.2%), while the reduction in intestinal metaplasia was not significant. Compared with the 5-year period before chemoprevention and in the absence of endoscopic screening, the effectiveness in reducing gastric cancer incidence during the chemoprevention period was 25% (rate ratio 0.753, 95% CI 0.372 to 1.524). The reduction in peptic ulcer disease was 67.4% (95% CI 52.2% to 77.8%), while the incidence of oesophagitis was 6% (95% CI 5.1% to 6.9%) after treatment. Conclusions Population-based eradication of H pylori infection has led to a significant reduction in gastric atrophy at the expense of increased oesophagitis. The ultimate benefit in reducing gastric cancer incidence and its mortality should be validated by a further long-term follow-up. Trial registration number NCT00155389.

Genetic alterations in gastric cancer: relation to histological subtypes, tumor stage, and Helicobacter pylori infection

BACKGROUND & AIMS A different spectrum of genetic changes including p53, c-erbB-2, c-met, adenomatous polyposis coli (APC), and deleted in colorectal cancer (DCC) is involved in gastric cancer (GC). The aim of this study was to correlate these alterations with histological subtypes, tumor stages, and Helicobacter pylori infection. METHODS Specimens of 163 patients with GC were immunostained for p53, c-erbB-2, and c-met, and polymerase chain reaction was performed in them to determine loss of heterozygosity (LOH) of APC and DCC. RESULTS Overexpression of p53 was more frequent in early intestinal than early diffuse GC and was noted in the stage progression of diffuse but not intestinal GC. Overexpression of c-erbB-2 occurred more commonly in intestinal GC and advanced GC of both types. Overexpression of c-met was greater in diffuse GC, particularly at advanced stage. LOH of APC was more common in intestinal GC irrespective of the stage but rarely in diffuse GC. LOH of DCC occurred primarily in advanced intestinal GC and infrequently in early GC or advanced diffuse GC. Alterations of these five genes were not correlated with H. pylori infection. CONCLUSIONS A distinct genetic pathway exists in gastric carcinogenesis of different histological subtypes and their tumor progression, in which H. pylori infection may play an equal role or no role.

Interleukin-6 Increases Vascular Endothelial Growth Factor and Angiogenesis in Gastric Carcinoma

Interleukin-6 (IL-6) is a proinflammatory cytokine associated with the disease status of gastric carcinoma (GC). Vascular endothelial growth factor (VEGF) is a potent tumor angiogenic factor in GC. In this study, we attempted to clarify whether IL-6 can regulate VEGF and angiogenesis in GC. GC samples from 54 surgical specimens were subjected to immunohistochemical examination of IL-6, VEGF, and tumor microvessels, and results showed that IL-6 was positively correlated with VEGF expression and tumor vasculature. We determined VEGF expression in four GC cell lines by ELISA, revealing that GC cells can produce significant amount of VEGF with increasing dose and duration of IL-6 stimulation. Next, a luciferase reporter gene assay was employed to determine the signaling pathway driving the VEGF promoter by IL-6, which showed that the JAK/STAT pathway is involved in the stimulation of VEGF gene expression. The effects of IL-6 on angiogenesis in vitro and in vivo were evaluated by HUVEC studies and the Matrigel plug assay, respectively. Results showed that IL-6 effectively promoted HUVEC proliferation and tube formation in vitro and Matrigel plug vascularization in vivo, primarily by inducing VEGF in GC. This study provides evidence that the multifunctional cytokine, IL-6, may induce VEGF expression which increases angiogenesis in gastric carcinogenesis.