Narong Khuntikeo

Exome sequencing identifies distinct mutational patterns in liver fluke–related and non-infection-related bile duct cancers

The impact of different carcinogenic exposures on the specific patterns of somatic mutation in human tumors remains unclear. To address this issue, we profiled 209 cholangiocarcinomas (CCAs) from Asia and Europe, including 108 cases caused by infection with the liver fluke Opisthorchis viverrini and 101 cases caused by non–O. viverrini–related etiologies. Whole-exome sequencing (n = 15) and prevalence screening (n = 194) identified recurrent somatic mutations in BAP1 and ARID1A, neither of which, to our knowledge, has previously been reported to be mutated in CCA. Comparisons between intrahepatic O. viverrini–related and non–O. viverrini–related CCAs demonstrated statistically significant differences in mutation patterns: BAP1, IDH1 and IDH2 were more frequently mutated in non–O. viverrini CCAs, whereas TP53 mutations showed the reciprocal pattern. Functional studies demonstrated tumor suppressive functions for BAP1 and ARID1A, establishing the role of chromatin modulators in CCA pathogenesis. These findings indicate that different causative etiologies may induce distinct somatic alterations, even within the same tumor type.

Urinary 8-Oxo-7,8-Dihydro-2′-Deoxyguanosine in Patients with Parasite Infection and Effect of Antiparasitic Drug in Relation to Cholangiocarcinogenesis

Parasite infection of Opisthorchis viverrini is a major risk factor for cholangiocarcinoma. Our previous immunohistochemical studies showed that O. viverrini infection induced oxidative DNA lesions in the bile duct epithelium during cholangiocarcinoma development. The current study assessed the levels of 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG), an oxidative DNA lesion, in the urine and leukocytes of O. viverrini–infected subjects and cholangiocarcinoma patients. Forty-nine O. viverrini–infected patients, 55 cholangiocarcinoma patients, and 17 healthy controls were enrolled in the study. We measured 8-oxodG levels in the urine and leukocytes of these subjects using an electrochemical detector coupled to high-performance liquid chromatography. O. viverrini–infected patients were assessed before treatment and 2 months and 1 year after praziquantel treatment. Urinary 8-oxodG levels were significantly higher in cholangiocarcinoma patients (6.83 ± 1.00 μg/g creatinine) than in O. viverrini–infected patients (4.45 ± 0.25 μg/g creatinine; P < 0.05) and healthy subjects (3.03 ± 0.24 μg/g creatinine; P < 0.01) and higher in O. viverrini–infected subjects than in healthy subjects (P < 0.01). The urinary 8-oxodG levels in O. viverrini–infected patients significantly decreased 2 months after praziquantel treatment and were comparable with levels in healthy subjects 1 year after treatment. Urinary 8-oxodG levels were significantly correlated with leukocyte 8-oxodG levels, plasma nitrate/nitrite levels, and aspartate aminotransferase activity. In conclusion, this study, in addition to our previous studies, indicates that 8-oxodG formation by parasite infection may play an important role in cholangiocarcinoma development. Urinary 8-oxodG may be a useful biomarker to monitor not only infection but also carcinogenesis. (Cancer Epidemiol Biomarkers Prev 2008;17(3):518–24)

Circulating CD14+CD16+ monocyte levels predict tissue invasive character of cholangiocarcinoma

Chronic inflammation as a risk factor for cancer development is driven in part by monocyte/macrophages, which in many cancers exhibit pro‐tumorigenic activity. In this study we identified elevation in CD14+CD16+, a minor blood monocyte subpopulation in cholangiocarcinoma (CCA) patients, compared to normal and biliary disease patient specimens. Tumour association was suggested by the observation that this elevated level decreased to normal after tumour resection. Moreover, the elevated level of CD14+CD16+ monocytes in CCA patient blood correlated with degree of MAC387‐positive (recent blood‐derived macrophage migrant‐specific marker) tumour‐associated macrophage infiltration as determined by immunohistochemistry. These CD14+CD16+ monocytes were suggested to enhance tumour progression as this subpopulation possesses (i) high expression of adhesion molecules (CD11c, CD49d, and CD54) and scavenger receptor (CD163), which enable them to adhere strongly to endothelial cells, and (ii) that peripheral blood monocytes from CCA patients express high levels of growth and angiogenic factor‐related genes (epiregulin, VEGF‐A and CXCL3). Elevation of peripheral CD14+CD16+ monocyte levels was associated with features associated with poor prognosis CCA parameters (non‐papillary type and high number of tissue macrophages). These data indicate that the CD14+CD16+ monocytes from CCA patients with pro‐tumorigenic characteristics may associate with rapid tumour progression and poor patient outcome. If confirmed in subsequent studies, the level of CD14+CD16+ monocytes may serve as a marker for disease activity in CCA patients and serve as a target for pathogenic macrophage specific drug development.

Tissue invasive macrophage density is correlated with prognosis in cholangiocarcinoma

Cholangiocarcinoma (CCA) is a high metastatic cancer with no effective treatment. Here, the pro-metastatic action of tissue macrophages in CCA is demonstrated and suggested as a prognostic marker and novel target for the therapeutic intervention of CCA. Fifty CCA tissues were immunohistochemically stained with a marker for reactive/infiltrating monocytes/macrophages (MAC387) and matrix metalloproteinase (MMP)-9. The antigenic densities in positively-stained cells along the leading edge of tumors were scored. Correlations between the densities of MAC387, MMP-9-positive cells, clinicopathological features and patient survival were investigated. High densities of MAC387-positive cells were detected in more than 60% of the CCA tissues. This was significantly associated with poor prognosis parameters (non-papillary and mass-forming type CCA). Overall survival was worst in patients with high-density MAC387-positive cells. Double immunofluorescent staining indicated that MAC387-positive cells co-expressed MMP-9. Immunohistochemical staining of MMP-9 in serial sections of CCA tissues indicated that MMP-9 was rarely expressed in CCA tumor cells, but highly expressed in MAC387-positive cells and polymorphonucleated infiltrating cells. Patients with high tissue expression levels of MAC387 in combination with MMP-9-expressing cells had the worst survival. These factors were found to be independent predictors of the post-resectional survival of CCA patients. Since CCA tumor cells rarely expressed MMP-9, it is likely that tissue macrophages are critical for degrading the extracellular matrix and for facilitating tumor metastasis. They may therefore serve as a prognostic marker for poor clinical outcome, and represent novel targets for the therapeutic intervention of CCA.

Overexpression of microRNA-21 regulating PDCD4 during tumorigenesis of liver fluke-associated cholangiocarcinoma contributes to tumor growth and metastasis.

MicroRNA, an endogenous noncoding RNA modulating gene expression, is a key molecule that by its dysregulation plays roles in inflammatory-driven carcinogenesis. This study aimed to investigate the role of oncomiR miR-21 and its target, the programmed cell death 4 (PDCD4) in tumor growth and metastasis of the liver fluke Opisthorchis viverrini-associated cholangiocarcinoma (CCA). The expression levels of miR-21 and PDCD4 were analyzed using the TaqMan miRNA expression assay and immunohistochemistry in liver tissues of both O. viverrini plus N-nitrosodimethylamine (NDMA)-treated hamsters and human CCA samples (n = 23 cases). The functional assay for miR-21 was performed in CCA cell lines by the anti-miR-21 and pre-miR-21 transfection procedures. The peak of miR-21 levels were reached at 2 (hyperplastic lesions) and 6 (CCA) months of the O. viverrini plus NDMA-induced group and had a reverse response with its target PDCD4 proteins. In human CCA, miR-21 was overexpressed in tumor tissues when compared with nontumor tissues (P = 0.0034) and had a negative correlation with PDCD4 protein (P = 0.026). It was also found that high expression of miR-21 was significantly correlated with shorter survival (P < 0.05) and lymph node metastasis (P = 0.037) of CCA patients. Transient transfection of pre-miR-21 reduced the PDCD4 level and resulted in an increase of M213 CCA cell growth and wound-induced migration ability. These results indicated that miR-21 plays a role in the carcinogenesis and metastasis of O. viverrini-associated CCA by suppressing the function of PDCD4. Modulation of aberrantly expressed miR-21 may be a useful strategy to inhibit tumor cell phenotypes or improve response to chemotherapy.

Overexpression of vitamin D receptor indicates a good prognosis for cholangiocarcinoma: implications for therapeutics.

Up‐regulation of vitamin D receptor (VDR) expression has been shown in several tumors and is thought to represent an important endogenous response to tumor progression. The authors aimed to verify the expression of VDR and its clinical significance in histologically proven cholangiocarcinoma (CCA).

Inflammation-related DNA damage and expression of CD133 and Oct3/4 in cholangiocarcinoma patients with poor prognosis

Nitrative and oxidative DNA damage plays an important role in inflammation-related carcinogenesis. Chronic inflammation such as parasite infection and primary sclerosing cholangitis can be an etiological factor of cholangiocarcinoma. Using a proteomic approach and double-fluorescent staining, we identified high expression and colocalization of albumin and cytokeratin-19 in liver fluke-associated cholangiocarcinoma tissues, compared with normal livers from cholangiocarcinoma patients and cadaveric donors, respectively. Albumin was detected not only in cells of hyperplastic bile ducts and cholangiocarcinoma, but also in liver stem/progenitor cell origin, such as canal of Hering, ductules, and ductular reactions, suggesting the involvement of stem/progenitor cells in cholangiocarcinoma development. To clarify the involvement of liver stem/progenitor cells in cholangiocarcinoma, we examined several stem/progenitor cell markers (CD133, CD44, OV6, and Oct3/4) in cholangiocarcinoma tissues analyzed by immunohistochemical staining, and measured 8-oxodG levels by using HPLC-ECD as an inflammation-related DNA lesion. In addition, a stem/progenitor cell factor Bmi1, 8-nitroguanine (formed during nitrative DNA damage), DNA damage response (DDR) proteins (phosphorylated ATM and γ-H2AX), and manganese-SOD (Mn-SOD) were analyzed by immunohistochemistry. Stem/progenitor cell markers (CD133, OV6, CD44, and Oct3/4) were positively stained in 56, 38, 47, and 56% of 34 cholangiocarcinoma cases, respectively. Quantitative analysis of 8-oxodG revealed significantly increased levels in CD133- and/or Oct3/4-positive tumor tissues compared to negative tumor tissues, as well as 8-nitroguanine formation detected by immunohistochemistry. In the cases of CD44- and/or OV6-positive tissue, no significant difference was observed. Cholangiocarcinoma patients with CD133- and/or Oct3/4-positive tumor tissues showed significantly lower expression of Mn-SOD and higher DDR protein, γ-H2AX. Moreover, CD133- and/or Oct3/4-positive cholangiocarcinoma patients had significant associations with tumor histology types, tumor stage, and poor prognoses. Our results suggest that CD133 and Oct3/4 in cholangiocarcinoma are associated with increased formation of DNA lesions and the DDR protein, which may be involved in genetic instability and lead to cholangiocarcinoma development with aggressive clinical features.

Inflammation-induced protein carbonylation contributes to poor prognosis for cholangiocarcinoma

Carbonylation is an irreversible and irreparable protein modification induced by oxidative stress. Cholangiocarcinoma (CCA) is associated with chronic inflammation caused by liver fluke infection. To investigate the relationship between protein carbonylation and CCA progression, carbonylated proteins were detected by 2D OxyBlot and identified by MALDI-TOF/TOF analyses in pooled CCA tissues in comparison to adjacent nontumor tissues and normal liver tissues. We identified 14 highly carbonylated proteins in CCA tissues. Immunoprecipitation and Western blot analyses of individual samples confirmed significantly greater carbonylation of serotransferrin, heat shock protein 70-kDa protein 1 (HSP70.1), and α1-antitrypsin (A1AT) in tumor tissues compared to normal tissues. The oxidative modification of these proteins was significantly associated with poor prognoses as determined by the Kaplan-Meier method. LC-MALDI-TOF/TOF mass spectrometry identified R50, K327, and P357 as carbonylated sites in serotransferrin, HSP70.1, and A1AT, respectively. Moreover, iron accumulation was significantly higher in CCA tissues with, compared to those without, carbonylated serotransferrin. We conclude that carbonylated serotransferrin-associated iron accumulation may induce oxidative stress via the Fenton reaction, and the carbonylation of HSP70.1 with antioxidative property and A1AT with protease inhibitory capacity may cause them to become dysfunctional, leading to CCA progression.

Helicobacter pylori in Thai patients with cholangiocarcinoma and its association with biliary inflammation and proliferation

OBJECTIVES To investigate whether Helicobacter spp. infection and the cagA of H. pylori are associated with hepatobiliary pathology, specifically biliary inflammation, cell proliferation and cholangiocarcinoma (CCA). METHODS Helicobacter species including H. pylori, H. bilis and H. hepaticus were detected in the specimens using the polymerase chain reaction (PCR). Biliary inflammation of the liver and gallbladders was semi-quantitatively graded on hematoxylin and eosin (H&E)-stained slides. Biliary proliferation was evaluated by immunohistochemistry using the Ki-67-labelling index. RESULTS Helicobacter pylori was found in 66.7%, 41.5% and 25.0% of the patients in the CCA, cholelithiasis and control groups (P < 0.05), respectively. By comparison, H. bilis was found in 14.9% and 9.4% of the patients with CCA and cholelithiasis, respectively (P > 0.05), and was absent in the control group. The cagA gene of H. pylori was detected in 36.2% and 9.1% of the patients with CCA and cholelithiasis, respectively (P < 0.05). Among patients with CCA, cell inflammation and proliferation in the liver and gallbladder were significantly higher among those DNA H. pylori positive than negative. CONCLUSIONS The present findings suggest that H. pylori, especially the cagA-positive strains, may be involved in the pathogenesis of hepatobiliary diseases, especially CCA through enhanced biliary cell inflammation and proliferation.

Histological confirmation of periductal fibrosis from ultrasound diagnosis in cholangiocarcinoma patients

Cholangiocarcinoma (CCA) has no specific clinical signs and symptoms and non‐specific bio‐ and tumor‐markers in the early disease stage. Usually patients present to tertiary care with advanced disease stage. In order to detect early cases of CCA that may present as a mass, dilatation of intrahepatic duct or combination, ultrasonography is accepted as a powerful imaging tool. A smaller mass or bile duct segmental dilatation requires further imaging for characterization, including computerized tomography (CT) or magnetic resonance imaging (MRI). We examined whether liver echo pattern was correlated with high risk for CCA in an endemic area of Opisthorchis viverrini (Ov). Ov infestation caused chronic inflammation of the biliary tree by periductal fibrosis (PDF), which may subsequently lead to CCA development. In our study, a World Health Organization classification of pattern of increased periportal echo (IPE) for schistosomiasis was applied. Two CCA patients gave consent for operation. Histopathological diagnosis showed both had cholangiocarcinoma with periductal fibrosis of the non‐tumorous area of the liver. Ultrasonography was used to compare the non‐tumorous area with parenchymal echo pattern and was shown to have an early CCA detection role and a surveillance role in an endemic area of Ov by detection of PDF.