Gadd45β silencing impaired viability and metastatic phenotypes in cholangiocarcinoma cells by modulating the EMT pathway

Growth arrest and DNA damage-inducible-β (Gadd45β) is a stress-response protein involved in a number of processes, including cell cycle control, DNA repair, survival and death control, and stress signaling, depending on its interactions. Gadd45β expression is dysregulated in numerous types of cancer, functioning as either a tumor promoter or a tumor suppressor. However, the functions of Gadd45β in cholangiocarcinoma (CCA), particularly in metastasis, has not been studied. The immunohistochemical analysis of Gadd45β expression revealed that 75% of histological specimens from patients with CCA expressed high levels of Gadd45β, and that high Gadd45β expression was associated with metastasis. The role of Gadd45β in CCA was examined using siRNA-mediated gene knockdown in HuCCA-1, a human CCA cell line established from a Thai patient. The effects of Gadd45β downregulation upon cell viability and death, invasion, migration, matrix metalloproteinase (MMP) activity and epithelial-mesenchymal transition (EMT) marker expression were investigated. Gadd45β knockdown impaired cell viability, which was associated with the induction of apoptosis. In addition, there was a marked reduction in invasion and migration, although MMP activity was unaffected. Impairment of these metastatic properties was accompanied by the decreased expression of EMT markers, including Slug, vimentin, claudin-1 and zona occludens protein 1, whereas E-cadherin expression was increased. The present study suggests that Gadd45β is involved in regulating the viability and the metastatic potential of CCA cells, which may be mediated by the modulation of the EMT pathway.

Molecular mechanisms of cholangiocarcinoma cell inhibition by medicinal plants

Cholangiocarcinoma (CCA) is one of the most common causes of cancer-associated mortality in Thailand. Certain phytochemicals have been demonstrated to modulate apoptotic signaling pathways, which may be targeted for the prevention and treatment of cancer. Therefore, the aim of the present study was to investigate the effect of specific medicinal plants on the inhibition of CCA cell proliferation, and to identify the molecular mechanisms underlying this. A WST-1 cell proliferation assay was performed using an RMCCA1 cell line, and apoptotic signaling pathways were also investigated using a PathScan Stress and Apoptosis Signaling Antibody Array Kit. The cell proliferation assay indicated that extracts from the Phyllanthus emblica fruit pulp (PEf), Phyllanthus emblica seed (PEs), Terminalia chebula fruit pulp (TCf), Terminalia chebula seed (TCs), Areca catechu seed (ACs), Curcuma longa (CL) and Moringa oleifera seed (MOs) exerted anti-proliferative activity in RMCCA1 cells. In addition, the PathScan assay revealed that certain pro-apoptotic molecules, including caspase-3, poly (ADP-ribose) polymerase, checkpoint kinase 2 and tumor protein 53, exhibited increased activity in RMCCA1 cells treated with the aforementioned selected plant extracts, with the exception of PEf. The mitogen-activated protein kinase (MAPK) pathways (including ERK1/2 and p38 MAPK) expression level was significantly increased in RMCCA1 cells pre-treated with extracts of PEs, TCf, CL and MOs. The activation of protein kinase B (Akt) was significantly demonstrated in RMCCA1 cells pre-treated with extracts of TCf, ACs and MOs. In summary, the present study demonstrated that extracts of PEs, TCf, TCs, ACs, CL and MOs exhibited anti-proliferative effects in CCA cells by inducing pro-apoptotic signals and modulating signal transduction molecules. Further studies in vivo are required to demonstrate the potential applications of specific plant extracts for the treatment of human cancer.

RED BLOOD CELL DUFFY ANTIGEN RECEPTOR FOR CHEMOKINES AND SUSCEPTIBILITY TO PLASMODIUM VIVAX INFECTION IN THAIS

Plasmodium vivax is the most prevalent malaria infection in Thailand. P. vivax uses Duffy Antigen Receptor for Chemokines (DARC) or Duffy antigen (Fy) as a receptor for entry into reticulocytes. Polymorphism of DARC exon 2 gene (FYA/FYB) in 40 P. vivax-infected subjects were investigated using nested PCR of blood samples spotted on filter paper collected during August 2013 to November 2013 from various malaria clinics in Thailand. Distribution of DARC genotypes was FYA 62.5%, FYB 20% and FYAB 17.5%, consistent with that of Hardy-Weinberg equation. Mutation G17A was found in both FYA and FYB alleles, resulting in Gyl48 and Asp48 of Fya and Fyb antigen, respectively. Mean parasitemia among the three groups is not statistically different. To the best of our knowledge, this is the first such study in Thailand.

Hypoxia enhances cholangiocarcinoma invasion through activation of hepatocyte growth factor receptor and the extracellular signal‑regulated kinase signaling pathway

Hypoxia is associated with tumor progression and poor prognosis in several cancer types. The present study aimed to examine the contribution of hypoxia (1% O₂) to cancer progression in a cholangiocarcinoma cell line, RMCCA-1. The molecular basis of the hypoxic response pathway was investigated. The results showed that hypoxia significantly accelerated cancer cell proliferation and enhanced cell invasion (P<0.05). By using receptor tyrosine kinase and intracellular signaling antibody array kits, an increased phosphorylation/activation of a number of signaling molecules, particularly hepatocyte growth factor receptor (Met) and extracellular signal-regulated kinase (ERK) 1/2, was identified. Inhibition of Met and ERK by small hairpin RNA and U0126, respectively, significantly inhibited hypoxia-induced the invasive potential of RMCCA-1 cells (P<0.05). However, according to immunohistochemical analysis, hypoxia-inducible factor-1α expression was not correlated with cancer staging or tumor differentiation in 44 samples of cholangicarcinoma cases. The findings of the present study emphasized the importance of Met/ERK pathway activation as a key molecular event that may be responsible for a more invasive phenotype in hypoxic tumors and suggest Met as a potential target for the treatment of cholangiocarcinoma.

Matrigel induces L-plastin expression and promotes L-plastin-dependent invasion in human cholangiocarcinoma cells

The function of the extracellular matrix (ECM) in the tumor microenvironment is not limited to forming a barrier against tumor invasion. As demonstrated in pathological specimens, cholangiocarcinoma samples exhibit an enrichment of the ECM surrounding the tumor cells. In this study, we examined involvement of the ECM in the regulation of the invasiveness of cholangiocarcinoma cells. The RMCCA1 cholangiocarcinoma cell line was cultured in culture plates either with or without a coating of reconstituted ECM basement membrane preparation (BD Matrigel matrix). In vitro invasion assays were then performed. In addition, the protein expression profile of the cell line was examined using two-dimensional gel electrophoresis and liquid chromatography-tandem mass spectrometry. The proteins expressed and their functional associations with cancer progression were determined. Culturing the RMCCA1 cell line in the BD Matrigel matrix induced cell invasion. Numerous proteins were induced by culturing the RMCCA1 cells in the matrix gel. The expression of L-plastin, an actin-binding protein, was significantly upregulated. The knockdown of L-plastin expression by siRNA silencing significantly suppressed the cellular response to matrix gel-stimulated cancer cell invasion. The ECM promotes the invasiveness of cholangiocarcinoma cells by upregulating L-plastin. These findings suggest the potential exploitation of this mechanism as a means of inhibiting the invasiveness of cholangiocarcinoma cells.

Role of mTOR inhibitor in cholangiocarcinoma cell progression

Cholangiocarcinoma (CCA) is a lethal malignancy of the biliary epithelium. CCA is resistant to currently available chemotherapy; therefore, new drugs as well as new molecular targets must be identified for the development of an effective treatment for CCA. The present study showed that RAD001 (everolimus), a derivative of rapamycin and an orally bioavailable mammalian target of rapamycin (mTOR) inhibitor, exhibits cytotoxic and antimetastatic effects in a CCA cell line, RMCCA-1. Treatment with low concentrations of RAD001 resulted in a significant reduction of in vitro invasion and migration of RMCCA-1, concomitant with a reduction of filopodia and alteration of the actin cytoskeleton. Although, matrix metalloproteinase-9 and -14 activities were unaltered. However, at high concentrations, RAD001 exhibited cytotoxic effects, reducing cell proliferation and inducing apoptotic cell death. Overall, RAD001 exhibits multiple effects mediated by the inhibition of the mTOR, which may serve as a promising agent for the treatment of CCA.

CD24 induces the invasion of cholangiocarcinoma cells by upregulating CXCR4 and increasing the phosphorylation of ERK1/2

Cholangiocarcinoma is a malignant biliary tract tumor with an extremely poor prognosis. CD24 expression has been linked to the aggressiveness of cholangiocarcinoma cells and the adverse prognosis of cholangiocarcinoma patients. In the present study, the underlying mechanism of aggressive CD24⁺ cholangiocarcinoma cell behavior was elucidated. The magnetic-activated cell sorting system was used to isolate CD24⁺ and CD24^- cell populations from RMCCA1 cholangiocarcinoma cells. Using a human tumor metastasis PCR array, it was observed that numerous tumor-associated genes were upregulated in the CD24⁺ cells, including CXC chemokine receptor type 4 (CXCR4). In addition, an intracellular signaling array demonstrated the activation of extracellular signal-regulated kinase (ERK)1/2, which is downstream of the CXCR4 signaling cascade, in the CD24⁺ cells. Inhibition of CXCR4 or ERK1/2 significantly inhibited the motility and invasiveness of the CD24⁺ cells. The present study indicates that CXCR4 and ERK1/2 are induced by CD24 and that these proteins are associated with cholangiocarcinoma cell invasion.

Validation of appropriate reference genes for gene expression studies in human thyroid gland using real-time RT-PCR

BACKGROUND

Gene-expression analysis is increasingly important in biological research, with real-time reverse transcription PCR (qRT-PCR) becoming the method of choice. The selection of reference genes is critical for gene expression studies because the expression of these genes may vary among tissues or cells and may change under certain circumstances. However there has not been any study that compares the stability of these reference genes in human thyroid specimens. Therefore, the authors studied the stability values and the appropriate reference genes expressed in thyroid specimens.

MATERIAL AND METHOD

25 human thyroid specimens were prospectively collected and extracted for their RNA. The candidate reference genes (hypoxanthine phosphoribosyl-transferase1 (HPRT1), ribosomal protein LI3a (RPLIA), beta-2-micro-globulin (B2M), beta-actin (ACTB) and glyceraldehyde-3-phosphate dehydrogenase (GAPD)) were amplified from these thyroid specimens using real-time RT-PCR. The stabilities of these candidate reference genes were analyzed using Normfinder software.

RESULTS

The authors found that HPRT1 has the highest stability value (40.38 x 10(9)) while GAPD has the lowest stability value (85.46 x 10(7)). Therefore GAPD is the most stably expressed gene in thyroid specimens.

CONCLUSION

Of the 5 genes studied, GAPD was found to be the best reference gene for gene expression studies in the thyroid gland. The present results may facilitate the choice of reference genes for expression studies in thyroid diseases.

Prognostic relevance of circulating CK19 mRNA in advanced malignant biliary tract diseases

AIM: To determine the role of circulating tumor cells (CTCs) in prediction of the overall survival of patients with advanced malignant biliary tract obstruction.

METHODS: We investigated the prognostic value of CTCs by examining two markers, cytokeratin (CK) 19 and human telomerase reverse transcriptase (hTERT) mRNA, in 40 patients diagnosed with advanced malignant biliary tract diseases. Quantitative real-time reverse transcription polymerase chain reaction was used to detect CK19 and hTERT mRNA in the peripheral blood of these patients. Overall survival was analyzed using the Kaplan-Meier method and Cox regression modeling.

RESULTS: Positive CK19 and hTERT mRNA expression was detected in 45% and 60%, respectively, of the 40 patients. Univariable analysis indicated that positive CK19 mRNA expression was significantly associated with worse overall survival (P = 0.009). Multivariable analysis determined that positive CK19 mRNA expression, patient’s age and serum bilirubin were each independently associated with overall survival.

CONCLUSION: CK19 mRNA expression levels in peripheral blood appear to provide a valuable marker to predict the overall survival of patients with advanced malignant biliary tract obstruction.

Basic fibroblast growth factor induces cholangiocarcinoma cell migration via activation of the MEK1/2 pathway

The purpose of this study was to investigate the roles played by basic fibroblast growth factor (bFGF) in the induction of cholangiocarcinoma cell progression and to identify the signal transduction molecules that are activated by bFGF in cholangiocarcinoma cells. FGF receptor-2 (FGFR2) was shown to be expressed in two cholangiocarcinoma cell lines (RMCCA1 and KKU-100). Samples from RMCCA1 and KKU-100 were assayed for the mRNA. Phosphorylation levels were determined by Western blotting. Treatment of the cholangiocarcinoma cells with bFGF enhanced signaling via the phosphorylation of MEK1/2, induced cholangiocarcinoma cell migration and resulted in high levels of actin polymerization. Moreover, treatment with a MEK1/2 inhibitor (U0126) attenuated the effect of bFGF-induced cholangiocarcinoma cell migration. Taken together, these observations indicate that bFGF enhances the migration of cholangiocarcinoma cells and that this enhancement is regulated by the phosphorylation of MEK1/2.

Expression of CD24 in cholangiocarcinoma cells is associated with disease progression and reduced patient survival

Cholangiocarcinoma is frequently found to invade local tissues and metastasize to distal organs. We investigated the expression of CD24 in cholangiocarcinoma samples and its prognostic significance. In addition, the cellular function of CD24 was studied in the RMCCA1 cholangiocarcinoma cell line. High CD24 expression significantly correlated with lymph node metastasis and positive surgical margins in cholangiocarcinoma patients. Univariate and multivariate analyses further demonstrated that CD24 expression was significantly associated with the overall survival of these patients (p=0.007 and p=0.040, respectively). For in vitro studies, the magnetic-activated cell sorting (MACS) system was used to isolate CD24+ and CD24- cell populations from RMCCA1 cells. CD24+ RMCCA1 cells had increased chemoresistance, adhesion (p=0.004), motility (p<0.001), migration (p<0.001) and invasion (p<0.001) capabilities when compared to CD24- cells. The matrix metalloproteinase (MMP)-7 was significantly elevated in CD24+ RMCCA1 cells (p=0.01). We found that inhibition of CD24 using siRNA silencing significantly decreased the invasive capacity of RMCCA1 cells. Both clinical and in vitro studies suggest that expression of CD24 is associated with cholangiocarcinoma disease progression. CD24 may thus serve as a new target for directed molecular therapy of cholangiocarcinoma.

Strong expression of CD133 is associated with increased cholangiocarcinoma progression

AIM: To determine the role of CD133 in cholangiocarcinoma progression.

METHODS: CD133 protein expression was evaluated by immunohistochemistry in 34 cholangiocarcinoma specimens. In addition, proliferation, chemoresistance and invasive properties of CD133-enriched (CD133⁺) and CD133-depleted (CD133^-) RMCCA1 cholangiocarcinoma cells were studied and compared.

RESULTS: Strong CD133 expression was observed in 67.6% (23/34) of the cholangiocarcinoma specimens. Strong expression of CD133 was significantly associated with nodal metastasis (P = 0.009) and positive surgical margin status (P = 0.011). In the in vitro study, both the CD133⁺ and CD133^- cells had similar proliferation abilities and resistance to chemotherapeutic drugs. However, the CD133⁺ cells had a higher invasive ability compared with CD133^- cells.

CONCLUSION: CD133+ cells play an important role in the invasiveness of cholangiocarcinoma. Targeting of the CD133+ cells may be a useful approach to improve treatment against cholangiocarcinoma.

Serum AFP and AFP-L3 in clinically distinguished hepatocellular carcinoma from patients with liver masses

OBJECTIVE

To determine the ability of alpha fetoprotein (AFP) and AFP-L3% serum level in discriminating hepatocellular carcinoma (HCC) from other types of liver mass.

MATERIAL AND METHOD

This study was performed according to a prospective-specimen-collection, retrospective-blinded-evaluation (PRoBE) design. A total of 109 HCC patients and 51 patients with other types of liver mass were consecutively selected. The levels of AFP and AFP-L3% in their sera were measured.

RESULTS

AFP levels in serum significantly elevated while AFP-L3% levels significantly decreased in HCC patients (AFP: p < 0.001, AFP-L3%: p < 0.001). The area under the curve (AUC) of a receiver operating characteristic (ROC) curve analysis for the diagnosis of HCC of AFP and AFP-L3% was 0.71 and 0.67, respectively. In addition, the serum level of AFP-L3% was significantly different between the small (mass occupying lesser than 50% of liver volume) and large (mass occupying more than 50% of liver volume) HCC (p = 0.040).

CONCLUSION

The diagnostic accuracy of serum AFP and AFP-L3% could provide them as candidate biomarkers to discriminate patients with HCC from patients with other types of liver mass. Serum AFP-L3% as a prognostic factor for HCC should be further evaluated in more details.

Serum NGAL to Clinically Distinguish Cholangiocarcinoma from Benign Biliary Tract Diseases

Aim. To determine whether the serum level of NGAL can discriminate cholangiocarcinoma from benign biliary tract disease in patients. Methods. This study was performed according to a prospective-specimen-collection, retrospective-blinded-evaluation (PRoBE) design. A total of 50 cholangiocarcinoma and 50 benign biliary tract disease cases were randomly selected from a cohort of consecutive cases of biliary tract diseases. Their sera were measured for the levels of NGAL and the widely used serum cholangiocarcinoma marker, carbohydrate antigen 19-9 (CA19-9). Results. The serum CA19-9 and NGAL levels were significantly elevated in cholangiocarcinoma patients (CA19-9: P < .001, NGAL: P < .001). The area under the curve (AUC) of a receiver operating characteristic (ROC) curve analysis for the diagnosis of cholangiocarcinoma of CA19-9 and NGAL was 0.81 and 0.79, respectively. Conclusion. The diagnostic accuracy of serum NGAL and CA19-9 makes them good candidates for use as biomarkers to discriminate cholangiocarcinoma patients from benign biliary tract disease patients.

Prospective study of MMP7 serum levels in the diagnosis of cholangiocarcinoma

AIM: To determine whether the serum level of matrix metalloproteinase-7 (MMP7) has the potential to diagnosis cholangiocarcinoma from benign biliary tract diseases.

METHODS: This study was performed according to the PRoBE (a prospective-specimen-collection, retrospective-blinded-evaluation) design. A total of 187 patients with obstructive jaundice were consecutively enrolled. After the diagnostic status of these patients was ascertained, their levels of serum MMP7 were assayed and compared with serum carbohydrate antigen 19-9 (CA19-9). This was conducted in a blinded case (cholangiocarcinoma)-control (benign biliary tract disease) setup.

RESULTS: MMP7 and CA19-9 serum levels were significantly elevated in cholangiocarcinoma patients (P < 0.001). The area under the curve (AUC) from a receiver operating characteristic (ROC) curve analysis for the diagnosis of cholangiocarcinoma, using MMP7 was more accurate than CA19-9 (AUC = 0.84, 95% CI: 0.778-0.903 for MMP7 and AUC = 0.79, 95% CI: 0.708-0.868 for CA19-9). The sensitivity and specificity of serum MMP7 (cut-off value of 5.5 ng/mL) was 75% and 78%, respectively, while the sensitivity and specificity of serum CA19-9 (cut-off value of 100 U/mL) was 68% and 87%, respectively.

CONCLUSION: Serum values of MMP7 and CA19-9 appear to be useful biomarkers for differentiating cholangiocarcinoma from benign biliary tract obstructive diseases.

The dual effects of delta(9)-tetrahydrocannabinol on cholangiocarcinoma cells: anti-invasion activity at low concentration and apoptosis induction at high concentration

Currently, only gemcitabine plus platinum demonstrates the considerable activity for cholangiocarcinoma. The anticancer effect of Delta (9)-tetrahydrocannabinol (THC), the principal active component of cannabinoids has been demonstrated in various kinds of cancers. We therefore evaluate the antitumor effects of THC on cholangiocarcinoma cells. Both cholangiocarcinoma cell lines and surgical specimens from cholangiocarcinoma patients expressed cannabinoid receptors. THC inhibited cell proliferation, migration and invasion, and induced cell apoptosis. THC also decreased actin polymerization and reduced tumor cell survival in anoikis assay. pMEK1/2 and pAkt demonstrated the lower extent than untreated cells. Consequently, THC is potentially used to retard cholangiocarcinoma cell growth and metastasis.

NGAL knockdown by siRNA in human cholangiocarcinoma cells suppressed invasion by reducing NGAL/MMP-9 complex formation

We studied the role of Neutrophil Gelatinase-associated Lipocalin (NGAL, lipocalin 2) in regulating the invasiveness of a cholangiocarcinoma cell line, RMCCA-1. RMCCA-1 cells expressed multiple forms of 25, 40, 75 and 115/135 kDa NGAL which were detected in the conditioned medium, whereas only the 25 kDa form was detected in the cell lysates. NGAL expression was induced by serum deprivation. NGAL downregulation by siRNA suppressed NGAL mRNA and protein expression by about 70-80%, concommittant with a significant reduction of in vitro invasiveness, migration and pro-MMP-9 activity, but not cell proliferation. Suppression of pro-MMP-9 activity paralleled a reduction of NGAL/MMP-9 complex in the conditioned medium, although MMP-9 mRNA expression was unaffected. Our data suggest that NGAL promotes the invasiveness of the cholangiocarcinoma cells by forming complex with MMP-9, stabilizing its activity and rendering the cancer cells to be more invasive.

Cholangiocarcinoma in a 24-year-old woman with hepatolithiasis

Hepatolithiasis is well known to represent an etiology of cholangiocarcinoma. The average age of patients with a diagnosis of cholangiocarcinoma that occurs as a complication of hepatolithiasis is about 62-year-old. Here, the authors present a case of cholangiocarcinoma that occurred in a 24-year-old woman who presented with the recurrent cholangitis from hepatolithiasis. Left hepatectomy with hepaticojejunostomy was performed because she had multiple stones in an atrophic left lobe of the liver. Histopathological examination revealed that it was cholangiocarcinoma located in the inflammatory left hepatic duct.

Detection of serum MMP-7 and MMP-9 in cholangiocarcinoma patients: evaluation of diagnostic accuracy

Background

Cholangiocarcinoma is an aggressive tumor with a tendency for local invasion and distant metastases. Timely diagnosis is very important because surgical resection (R0) remains the only hope for a cure. However, at present, there is no available tumor marker that can differentiate cholangiocarcinoma from benign bile duct disease. Previous studies have demonstrated that matrix metalloproteinase (MMP)-7 and MMP-9 are frequently expressed in cholangiocarcinoma specimens.

Methods

This study was designed to determine whether the serum levels of MMP-7 and MMP-9 can discriminate cholangiocarcinoma patients from benign biliary tract disease patients in comparison to carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9). We measured the level of CEA, CA19-9, MMP-7 and MMP-9 in the serum of 44 cholangiocarcinoma and 36 benign biliary tract diseases patients.

Results

Among the serum levels of CEA, CA19-9, MMP-7 and MMP-9, only the serum MMP-7 level was significantly higher in the patients with cholangiocarcinoma (8.9 ± 3.43 ng/ml) compared to benign biliary tract disease patients (5.9 ± 3.03 ng/ml) (p < 0.001). An receiver operating characteristic (ROC) curve analysis revealed that the detection of the serum MMP-7 level is reasonably accurate in differentiating cholangiocarcinoma from benign biliary tract disease patients (area under curve = 0.73; 95% CI = 0.614–0.848). While the areas under the curve of the ROC curves for CEA, CA19-9 and MMP-9 were 0.63 (95% CI = 0.501–0.760), 0.63 (95% CI = 0.491–0.761) and 0.59 (95% CI = 0.455–0.722), respectively.

Conclusion

Serum MMP-7 appears to be a valuable diagnostic marker in the discrimination of cholangiocarcinoma from benign biliary tract disease. Further prospective studies for serum MMP-7 measurement should be carried out to further investigate the potential of this molecule as a biomarker of cholangiocarcinoma.

Inhibition of PI3K increases oxaliplatin sensitivity in cholangiocarcinoma cells

BACKGROUND

Resistance of cholangiocarcinoma to chemotherapy is a major problem in cancer treatment. The mechanism of resistance is believed to involve phosphoinositide-3- kinase (PI3K)/Akt activation. Although the platinum-containing compound oxaliplatin has been extensively used in the treatment of several solid tumors, recent data regarding its use to treat cholangiocarcinoma are ambiguous. Oxaliplatin resistance in this disease could potentially involve PI3K pathways. We, therefore, examined the effects of PI3K pathways in cholangiocarcinoma cells in modulating oxaliplatin resistance.

RESULTS

After exposing the cholangiocarcinoma cell lines RMCCA1 and KKU100 to oxaliplatin, the levels of Akt and mTOR phosphorylation increased, as shown by western blot analysis. The WST-1 cell proliferation assay showed increased inhibition of cell growth under high concentrations of oxaliplatin. The combination of oxaliplatin with LY294002, an inhibitor of PI3K, resulted in a remarkable arrest of cell proliferation. Deactivation of mTOR by RAD001 was also synergistic with oxaliplatin, although to a lesser extent. The combination of oxaliplatin and a PI3K inhibitor also resulted in a significant induction of apoptosis, as demonstrated by the TUNEL assay.

CONCLUSION

Activation of PI3K might protect cholangiocarcinoma cells from oxaliplatininduced cytotoxicity. Although the inhibition of PI3K and the inhibition of mTOR both enhance oxaliplatin-induced cytotoxicity, PI3K inhibition has a greater effect. Targeting the PI3K pathway may be a useful approach to improve the chemotherapeutic sensitivity of cholangiocarcinoma.

The effect of doxorubicin on the changes of serum vascular endothelial growth factor (VEGF) in patients with hepatocellular carcinoma after transcatheter arterial chemoembolization (TACE)

BACKGROUND

Treatment of hepatocellular carcinoma (HCC) with transcatheter arterial chemoembolization (TACE) is known to induce vascular endothelial growth factor (VEGF) expression. A recent study has shown that doxorubicin can repress hypoxic induction of VEGF expression in human cancer cells.

OBJECTIVE

To evaluate the combination effects of doxorubicin and TACE on the change of serum VEGF after TACE.

MATERIAL AND METHOD

Thirty patients with unresectable HCC were assigned into two groups, the experiment group (n = 15) received TACE with doxorubicin (25-50 mg) plus mitomycin C (5-10 mg), and the control group (n = 15) received TACE with mitomycin C (5-10 mg). Serum VEGF before and after TACE (24 hour) was measured by quantitative sandwich enzyme-linked immunosorbent assay.

RESULTS

Baseline serum VEGF was correlated with the size of tumor (r2 = 0.85; p = 0.03). In addition, serum VEGF was significantly elevated after TACE (p = 0.014). However; the change of serum VEGF after TACE is not statistically different in both groups (p = 0.72). At 2-years, the overall survival was 38% and 40% in the experiment and control group, respectively (p = 0.48).

CONCLUSION

The present study suggests that doxorubicin improves neither the level of serum VEGF nor the survival in HCC patients treated with TACE.

Detection of hTERT mRNA in gastrointestinal tract cancer specimens

Human telomerase consisting of telomerase RNA template (hTR) and telomerase reverse transcriptase (hTERT) provides a mechanism for synthesis of telomere repeats that prolongs life span of cells. Telomerase activity is present in germ-line and malignant tumor cells but not in most normal human somatic cells. This study determined hTERT mRNA level in tissue samples from patients with gastrointestinal tract (GI) cancers. Tissue samples were obtained from 22 GI cancer patients, 3 gastrointestinal stomal tumors (GIST) and 25 corresponding non-cancerous tissues. hTERT expression was determined by real-time reverse transcriptase-polymerase chain reaction (RT-PCR) using Taqman probe, hTERT mRNA was detected in 12 of 22 cancerous tissue samples. Six of 8 tissue samples obtained from patients with hepatocellular carcinoma and cholangiocarcinoma were positive for hTERT. However, hTERT mRNA was not detected in GIST and non-cancerous tissues. These results suggest that hTERT may be an effective target for cancer therapies to treat many type of GI cancers including cholangiocarcinoma and hepatocellular carcinoma.

TaqMan real-time PCR assay for specific detection of Opisthorchis viverrini DNA in Thai patients with hepatocellular carcinoma and cholangiocarcinoma

The aim of this study was to develop TaqMan real-time PCR assay that detected Opisthorchis viverrini DNA from 18 normal and 18 tumor tissue specimens from Thai patients with hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA), who underwent liver resection from October 2005 to May 2006. Control liver specimens were seven non-primary liver cancers. A conserved probe representing 100% sequence homology was used as a reference for O. viverrini-specific probe. Five of six tumors (83%) and all six normal tissues from CCA group; and seven of twelve tumors (58%) and ten of twelve normal tissues (83%) from HCC group were found to have O. viverrini DNA. The O. viverrini DNA detection among HCC and CCA patients were not associated (p=0.193; 90%CI). This RT-PCR will be a useful tool for investigating the relationship between cancer type and presence of the parasite and also for conducting epidemiological surveys.

Detection of VacA gene specific for Helicobactor pylori in hepatocellular carcinoma and cholangiocarcinoma specimens of Thai patients

In order to investigate and compare the presence of Helicobacter pylori VacA in primary liver cancer specimens (12 hepatocellular carcinoma and 6 cholangiocarcinoma) and control liver specimens (7 non-primary liver cancer) from Thai patients who underwent liver resection, H. pylori VacA gene was assayed in extracted DNA by real-time polymerase chain reaction. The selected amplicons revealed high homology compared with H. pylori VacA sequence. H. pylori VacA gene was detected in all primary liver cancer specimens and in 71% (5/7) of control liver specimens.

Roles of the MEK1/2 and AKT pathways in CXCL12/CXCR4 induced cholangiocarcinoma cell invasion

AIM: To evaluate the expression of C-X-C motif chemokine receptor 4 (CXCR4) and its signaling cascades, which were previously identified as a key factor for cancer cell progression and metastasis, in cholangiocarcinoma cell lines.

METHODS: The expression of CXCR4 and its signaling cascades were determined in the cholangiocarcinoma cell lines (RMCCA1 and KKU100) by Western blotting. The invasion assays and the detection of actin polymerization were tested in these cholangiocarcinoma cells treated with CXC chemokine ligand -12 (CXCL12).

RESULTS: Expression of CXCR4 was detected in both cholangiocarcinoma cell lines and activation of CXCR4 with CXCL12 triggered the signaling via the extracellular signal-regulated kinase-1/2 (ERK1/2) and phosphoinositide 3-kinase (PI3K) and induction of cholangiocarcinoma cell invasion, and displayed high levels of actin polymerization. Addition of CXCR4 inhibitor (AMD3100) abrogated CXCL12-induced phosphorylation of MEK1/2 and Akt in these cells. Moreover, treatment with MEK1/2 inhibitor (U0126) or PI3K inhibitor (LY294002) also attenuated the effect of CXCL12-induced cholangiocarcinoma cell invasion.

CONCLUSION: These results indicated that the activation of CXCR4 and its signaling pathways (MEK1/2 and Akt) are essential for CXCL12-induced cholangiocarcinoma cell invasion. This rises Implications on a potential role for the inhibition of CXCR4 or its signal cascades in the treatment of cholangiocarcinoma.

Role of ciprofloxacin in patients with cholestasis after endoscopic retrograde cholangiopancreatography

AIM: To determine the role of ciprofloxacin in reducing cholangitis in cholestatic patients with adequate biliary drainage after endoscopic retrograde cholangiopancreatography (ERCP).

METHODS: A randomized, controlled trial was performed in 48 cholestatic patients at Rajavithi Hospital (Tertiary Referral Center for ERCP: 600 cases per year). All the 48 patients received 200 mg ciprofloxacin intravenous injection for 30 min before starting any procedures, and then were randomly divided in two groups. Twenty-two patients in study group continually received ciprofloxacin until 48 h after ERCP. Causes of biliary obstruction, bacteriology of bile and blood (in cholangitis) and clinical cholangitis were recorded.

RESULTS: Forty-eight patients were enrolled and divided into continuous ciprofloxacin treatment group (n = 22) and discontinuous ciprofloxacin treatment group (n = 26). During ERCP, stones were found in 22 patients, malignant diseases in 24 patients and other pathologic lesions in 5 patients. One (4.5%) of the 22 patients who received ciprofloxacin and 2 (6.3%) of the 26 patients who discontinued ciprofloxacin after ERCP developed cholangitis (relative risk = 0.71; 95% CI = 0.14-3.65; p = 0.88). Bacterobilia was found in 27 (56.3%) out of 48 patients. E. coli and Streptococcus viridans were the most common organisms.

CONCLUSION: Continual use of ciprofloxacin in patients with cholestasis after adequate biliary drainage procedures plays no role in reducing cholangitis.

Establishment and characterization of a cholangiocarcinoma cell line (RMCCA-1) from a Thai patient

AIM

To establish and characterize a new cell line derived from peripheral cholangiocarcinoma of a Thai patient.

METHODS

The peripheral cholangiocarcinoma specimen surgically obtained from the patient was aseptically processed by washing and mincing before culturing in Ham's F12 medium containing 10% fetal bovine serum. After 3 mo, when the cell line has become homogeneous and stabilized, several features were investigated, including growth characteristics, immunofluorescence staining for cytokeratins, expression of tumor markers, chromosomal analysis by G-banding and multicolour fluorescence in situ hybridization (mFISH), in vitro migration and invasion characteristics.

RESULTS

The RMCCA-1 cell line has been established. These cells proliferated as a monolayer with a population doubling time of 48 h. Immunofluorescence staining showed positive staining for human cytokeratin 7 and 19 verifying the biliary epithelial origin. RMCCA-1 secreted carbohydrate antigen 19-9 (CA19-9), but insignificant levels of carcinoembryonic antigen (CEA) and alpha-fetoprotein (AFP). Chromosome analysis identified aneuploidy karyotypes with a modal chromosome number of 59. RMCCA-1 exhibited a low level of in vitro invasiveness, but a high degree of motility. The cell line exhibited a significant number of chromosomal aberrations as shown by mFISH and G-banding methods.

CONCLUSION

A new cell line derived from peripheral cholangiocarcinoma of a Thai patient has been established. This cell line shows a low level of in vitro invasiveness, but a high degree of motility. It will serve as a valuable tool for further studies on tumor biology, molecular pathogenesis, metastatic mechanism and response to therapeutic drugs of cholangiocarcinoma.

Involvement of c-Met/hepatocyte growth factor pathway in cholangiocarcinoma cell invasion and its therapeutic inhibition with small interfering RNA specific for c-Met

BACKGROUND

Hepatocyte growth factor receptor (c-Met) plays an important role in many functions of cancer cells. We examined the roles of c-Met and its downstream signaling molecules in cholangiocarcinoma cell lines RMCCA1 and HuCCA1.

MATERIALS AND METHODS

The expression of c-Met and their signaling cascades were determined in RMCCA1 and HuCCA1 cholangiocarcinoma cell lines by Western blotting. Small interfering RNA (siRNA) specific for c-Met was used to suppress the expression of c-Met. The proliferation, migration and invasion assay were tested in these cholangiocarcinoma cells treated with hepatocyte growth factor (HGF).

RESULTS

Activation of c-Met with HGF triggered the signaling via the ERK cascade mediated by sequential phosphorylation of MEK1/2 and MAPK and induction of cholangiocarcinoma cell invasion. The expression of c-Met in cholangiocarcinoma cells was suppressed by treatment with small interfering RNA (siRNA) specific for c-Met, and resulted in decrease in phosphorylation of MEK1/2. Furthermore, treatment with siRNA specific for c-Met or MEK inhibitor U0126 inhibited cholangiocarcinoma cell invasion induced by HGF.

CONCLUSIONS

These results indicated that HGF and c-Met involved in the mechanism of cholangiocarcinoma cell invasion. It implies a potential role for the inhibition of c-Met in the treatment of cholangiocarcinoma.

Circulating hTERT mRNA as a tumor marker in cholangiocarcinoma patients

AIM: To investigate human telomerase reverse transcriptase (hTERT) mRNA in the serum of cholangiocarcinoma patients.

METHODS: The serum of thirty three cholangiocarcinoma patients, forty one benign biliary tract disease patients and ten healthy volunteers were collected and analyzed for the expression of hTERT mRNA by real-time reverse transcriptase-polymerase chain reaction (RT-PCR). We then examined the correlation between values of serum hTERT mRNA and the pathological staging of cholangiocarcinoma.

RESULTS: hTERT mRNA was detected in 28 of 33 (84.85%) of serum obtained from cholangiocarcinoma patients and 9 of 41 (21.9%) of serum obtained from benign biliary tract disease patients. hTERT mRNA was not detected in any serum obtained from healthy volunteers. on the other hand the common tumor marker, CA19-9 was detected in 20 of 33 (60.6%) of serum obtained from cholangiocarcinoma patients and 8 of 41 (19.5%) of serum obtained from benign biliary tract disease patients. However, no correlation was found between the present of serum hTERT mRNA and tumor staging.

CONCLUSION: These results indicate that the detection of circulating hTERT mRNA was identified in almost all cholangiocarcinoma patients. It offers a novel tumor marker, which can be used as a complementary study for diagnosis of cholangiocarcinoma.

Receptor-binding cancer antigen expressed on SiSo cells can be detected in metastatic lymph nodes from gastrointestinal cancers

AIM: To investigate the expression of receptor-binding cancer antigen expressed on SiSo cells (RCAS1) in metastatic lymph nodes from gastrointestinal cancer.

METHODS: Metastatic lymph nodes from gastrointestinal cancer were detected for RCAS1 by immunohistochemical staining and mRNA in situ hybridization.

RESULTS: A total of 102 metastatic lymph nodes from bile duct, gastric, colon, and pancreatic cancer were investigated for RCAS1 expression. The immunoreactivity of RCAS1 was identified in 100% of metastatic lymph nodes. Both local and distant metastatic lymph nodes showed RCAS1 expression. On the contrary, specimens of non-cancerous lymph nodes were negative for RCAS1. The result of mRNA in situ hybridization was also confirmed by the finding of immunohistochemical staining. RCAS1 mRNA was detected in all tumor cells that metastasized to lymph nodes.

CONCLUSION: All metastatic lymph nodes express RCAS1 in tumor cells at both protein and mRNA levels, and RCAS1 should be used as a complementary factor for identification of metastatic lymph nodes from gastrointestinal cancers.

All-trans retinoic acid inhibits the cell proliferation but enhances the cell invasion through up-regulation of c-met in pancreatic cancer cells

All-trans retinoic acid (ATRA) inhibits proliferation of cancer. However, the effects of ATRA on scattering and invasion of pancreatic cancer cells remain unknown. Also, the effects of ATRA on c-Met expression in pancreatic cancer have never been addressed so far. The effects of ATRA on a pancreatic cancer cell line, Capan-1, were determined by proliferation assay, scattering assay and invasion assay. In addition, the expression of c-Met in pancreatic cancer cell lines treated with ATRA was investigated by real-time PCR and western blotting. The growth-inhibitory effect of ATRA was found when the cells were cultured with 5 microM ATRA for 3 days. In cell scattering assay, ATRA-treated pancreatic cancer cells were found to spread out from their colonies. In invasion assay, cells treated with ATRA invaded the matrigel more than vehicle-treated cells. The expression of c-Met was up-regulated both in the mRNA and protein levels after the treatment of ATRA. The highest expression was found at 48 h after the treatment. ATRA induced scattering and invasion of pancreatic cancer cells, although it inhibited proliferation of those cells. In addition, ATRA also increased the protein level of c-Met. These findings may indicate that the use of retinoic acid as an anti-cancer therapeutic drug needs some additional treatments to control cell invasion or scattering.

No expression of human leukocyte antigen G (HLA-G) in colorectal cancer cells

Although there is a specific antitumor immune response in the body, colorectal cancer cells progressively develop. This fact indicated that the cancer cells could have a variety of mechanisms to evade or escape the immune system. HLA-G is identified to inhibit the recognition of NK-cell in various kinds of cancers. This study investigated the expression of HLA-G in colorectal cancer. Eighty five specimens of colorectal cancer, carcinoma in situ and adenomatous polyp were examined by immunohistochemistry and RT-PCR for the detection of human leukocyte antigen (HLA)-G The expression of HLA-G was not found in all colorectal specimens (85/85) both protein level and transcription level, suggesting that the expression of HLA-G is not a possible immune evasion mechanism of colorectal cancer cell.

Upregulation of tumour associated antigen RCAS1 is implicated in high stages of colorectal cancer

BACKGROUND

RCAS1 (receptor binding cancer antigen expressed on SiSo cells) is a tumour associated antigen. It is involved in immune evasion by tumour cells, by binding to receptors on cells involved in the immune response, such as T cells and natural killer cells, and inducing apoptosis. High expression of RCAS1 has been demonstrated immunohistochemically in tumours of the cervix, breast, lung, and stomach; however, the expression of RCAS1 has never been investigated in colorectal cancer.

AIMS

To investigate the expression of RCAS1 in colorectal cancer and identify at which stages of colorectal carcinogenesis it is expressed.

METHODS

Sixty surgically resected colorectal cancer specimens obtained from Rajavithi Hospital, Bangkok, Thailand were studied. RCAS1 expression was detected immunohistochemically using monoclonal anti-RCAS1 antibody. RCAS1 mRNA expression was also investigated by reverse transcription polymerase chain reaction in the freshly isolated tissues, and serum RCAS1 was measured by enzyme linked immunosorbent assay.

RESULTS

Staining for the RCAS1 protein was intense in high stages of colorectal cancer, but weak in normal tissues. The RCAS1 mRNA results correlated with the immunohistochemistry results. Positive serum RCAS1 concentrations were found in 10 of 18 patients with stage II disease and 12 of 32 with stage III and IV, but not in patients with stage I disease. All lymph node and liver metastases showed high expression of RCAS1 protein.

CONCLUSIONS

RCAS1 appears to be upregulated in high stages of colorectal cancer, both in the serum and the tissue. RCAS1 expression might be a useful additional criterion for staging this cancer.

Simple technique in the measurement of liver volume

The measurement of liver volume is considered to be a highly effective prediction of postoperative liver failure in hepatectomized patients and selection of the proper size of the liver obtained from a living donor. The aim of the paper was therefore, to develop a simple, inexpensive and practical technique for the measurement of liver volume. Computerized tomography (CT) imaging sections were used to measure sectional areas of liver sections via a graphic program. The volumes of livers were then calculated from the combined sectional areas using mean-area, end-area, and prismodial methods. The calculated volumes of livers obtained were compared to those manually measured in a water replacement technique. The findings of the results indicated that the liver volume could be estimated from CT scan films with typically less than 5 per cent difference compared to the manual method.