Establishment and identification of the human multi-drug-resistant cholangiocarcinoma cell line QBC939/ADM. Mol Biol Rep. 2011;38:3075-3082. [PMID: 20111907 DOI: 10.1007/s11033-010-9975-7]

Development and Characterization of Human Primary Cholangiocarcinoma Cell Lines

Cholangiocarcinoma (CCA) is the second most common primary liver tumor and is associated with late diagnosis, limited treatment options, and a 5-year survival rate of around 30%. CCA cell lines were first established in 1971, and since then, only 70 to 80 CCA cell lines have been established. These cell lines have been essential in basic and translational research to understand and identify novel mechanistic pathways, biomarkers, and disease-specific genes. Each CCA cell line has unique characteristics, reflecting a specific genotype, sex-related properties, and patient-related signatures, making them scientifically and commercially valuable. CCA cell lines are crucial in the use of novel technologies, such as three-dimensional organoid models, which help to model the tumor microenvironment and cell-to-cell crosstalk between tumor-neighboring cells. This review highlights crucial information on CCA cell lines, including: i) type of CCA (eg, intra- or extrahepatic), ii) isolation source (eg, primary tumor or xenograft), iii) chemical digestion method (eg, trypsin or collagenase), iv) cell-sorting method (colony isolation or removal of fibroblasts), v) maintenance-medium choice (eg, RPMI or Dulbecco's modified Eagle's medium), vi) cell morphology (eg, spindle or polygonal shape), and vii) doubling time of cells.

Establishment of drug-resistant cell lines under the treatment with chemicals acting through different mechanisms

The problem of chemoresistance development is an inescapable flipside of modern oncotherapy, in particular for сolorectal cancer patients. The search for or development of drugs effective against resistant tumors involves the use of model resistant cell lines in vitro. To obtain such lines, we reproduced the development of chemoresistance of human colon adenocarcinoma cells under the treatment with drugs of different mechanisms, a cytostatic (paclitaxel) and a targeted agent (Nutlin-3a, an inhibitor of p53-Mdm2 protein-protein interaction). In each case, we gradually increased the content of the substance in the medium, starting from effective concentrations that do not cause total cell death. When studying the lines resistant to the corresponding drug, we noted a reduced sensitivity to the drug of another mechanism of action. Analysis of the original and resistant lines showed that the cells use the universal efflux defense mechanism. The observed effect can be partially neutralized using inhibitors of the ABC transport proteins, including P-glycoprotein, known for its oncoprotective function. The role of the latter was confirmed by real-time RT-PCR and Western blotting.

Experimental models to unravel the molecular pathogenesis, cell of origin and stem cell properties of cholangiocarcinoma

Human cholangiocarcinoma (CCA) is an aggressive tumour entity arising from the biliary tree, whose molecular pathogenesis remains largely undeciphered. Over the last decade, the advent of high-throughput and cell-based techniques has significantly increased our knowledge on the molecular mechanisms underlying this disease while, at the same time, unravelling CCA complexity. In particular, it becomes clear that CCA displays pronounced inter- and intratumoural heterogeneity, which is presumably the consequence of the interplay between distinct tissues and cells of origin, the underlying diseases, and the associated molecular alterations. To better characterize these events and to design novel and more effective therapeutic strategies, a number of CCA experimental and preclinical models have been developed and are currently generated. This review summarizes the current knowledge and understanding of these models, critically underlining their translational usefulness and limitations. Furthermore, this review aims to provide a comprehensive overview on cells of origin, cancers stem cells and their dynamic interplay within CCA tissue.

Establishment and characterization of gemcitabine-resistant human cholangiocarcinoma cell lines with multidrug resistance and enhanced invasiveness

To establish and characterize the gemcitabine-resistant cholangiocarcinoma (CCA) cell lines, CCA KKU‑M139 and KKU‑M214 cell lines were exposed stepwisely to increasing gemcitabine (GEM). The resultant drug-resistant cell lines, KKU‑M139/GEM and KKU‑M214/GEM, retained the resistant phenotype in drug-free medium at least for 2 months. Sulforhodamine B assay demonstrated that KKU‑M139/GEM and KKU‑M214/GEM were 25.88- and 62.31-fold more resistant to gemcitabine than their parental cells. Both gemcitabine-resistant cell lines were cross-resistant to 5-fluorouracil (5-FU), doxorubicin and paclitaxel indicating their multidrug-resistant nature. Using reverse transcriptase-polymerase chain reaction (RT-PCR), real-time PCR and western blot analyses, gemcitabine-resistant cells showed upregulation of RRM1 and downregulation of hENT1 and dCK. In relation to multidrug resistance, these cell lines showed upregulation of multidrug resistance protein 1 (MRP1) leading to an increase of drug efflux. Using cell adhesion and Boyden chamber transwell assays, these cell lines also showed higher cell adhesion, migration and invasion capabilities via the activations of protein kinase C (PKC), focal adhesion kinase (FAK), extracellular signal-regulated kinase-1/2 (ERK1/2) and nuclear factor-κB (NF-κB). Higher activity of matrix metalloproteinase-9 (MMP-9) and urokinase plasminogen activator (uPA) was also observed by a gelatin zymography assay and a casein-plasminogen zymography assay. Flow cytometry analysis indicated the G2/M arrest regulated by downregulation of cyclin B1 and cyclin-dependent kinase 1 (Cdk1) resulted in an extended population doubling time. Using Annexin V/propidium iodide staining, evasion of apoptosis via an intrinsic pathway was observed in both cell lines in association with upregulation of Bcl-2 and downregulation of Bax. Interestingly, Fas was additionally downregulated in KKU‑M214/GEM supporting the view of its higher GEM resistant characteristics. These findings indicate that long-term exposure of CCA cell lines to gemcitabine induce not only multidrug resistance but also enhance their invasiveness.

β-escin reverses multidrug resistance through inhibition of the GSK3β/β-catenin pathway in cholangiocarcinoma

AIM: To develop a safe and effective agent for cholangiocarcinoma (CCA) chemotherapy.

METHODS: A drug combination experiment was conducted to determine the effects of β-escin in combination with chemotherapy on CCA cells. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay was performed to determine the effects of β-escin and common chemotherapeutics on the proliferation of human CCA cells (QBC939, Sk-ChA-1, and MZ-ChA-1). Immunocytochemistry was used to detect the expression of P-glycoprotein (P-gp) protein. Luciferase reporter assay was used to detect the activation of the Wnt/β-catenin pathway. The protein levels of P-gp, pS9-GSK3β, pT216-GSK3β, GSK3β, β-catenin, and p-β-catenin were further confirmed by western blotting.

RESULTS: The drug sensitivity of QBC939 and QBC939/5-fluorouracil (5-FU) cells to 5-FU, vincristine sulfate (VCR), or mitomycin C was significantly enhanced by β-escin compared with either agent alone (P < 0.05). In addition, the combination of β-escin (20 μmol/L) with 5-FU and VCR was synergic with a combination index < 1. Further investigation found that the mRNA and protein expression of P-gp was down-regulated by β-escin. Moreover, β-escin induced GSK3β phosphorylation at Tyr-216 and dephosphorylation at Ser-9, resulting in phosphorylation and degradation of β-catenin. Interestingly, activation of the GSK3β/β-catenin pathway induced by Wnt3a resulted in up-regulation of P-gp, which was effectively abolished by β-escin, indicating that β-escin down-regulated P-gp expression in a GSK3β-dependent manner.

CONCLUSION: β-escin was a potent reverser of P-gp-dependent multidrug resistance, with said effect likely being achieved via inhibition of the GSK3β/β-catenin pathway and thus suggesting a promising strategy of developing combination drugs for CCA.

Verapamil and rifampin effect on p-glycoprotein expression in hepatocellular carcinoma

Background:

High expression of p-glycoprotein (P-gp) has been associated with a poor prognosis in patients with hepatocellular carcinoma (HCC). It is likely that P-gp overexpression is responsible for multidrug resistance in HCC.

Objectives:

The aim of this study was to elucidate the effect of potent carcinogen nitrosamine with and without verapamil and rifampin drugs on P-gp expression at the mRNA level in HCC.

Materials and Methods:

Four groups of rats (n = 5) were selected with different treatments and one group as control. mRNA concentration changes were monitored using quantitative PCR (QPCR).

Results:

A significant difference was found between verapamil treated group and the control regarding the mRNA level. The mdr1a mRNA was significantly decreased in the verapamil group (P ≤ 0.001). Rifampin administrated group had a decreased level of the mdr1a mRNA compared to the control group (P ≤ 0.006). No significant changes were observed in HCC induced rats regarding the mdr1a mRNA level when treated with verapamil and rifampin. An enhanced expression of the mdr1a gene was found In the HCC induced animals when treated with drugs.

Conclusions:

Verapamil and rifampin were found specific and effective against P-gp expression in HCC. In conclusion, treatment efficacy of most anticancer drugs is increased in combination with verapamil and rifampin against most advanced HCC.

Inhibition of Wnt/β-catenin signaling downregulates P-glycoprotein and reverses multi-drug resistance of cholangiocarcinoma

The development of multi-drug resistance (MDR) represents a major obstacle in the successful treatment of cancers. However, the factors and mechanisms that lead to MDR in cholangiocarcinoma (CCA), a chemoresistant bile duct carcinoma with a poor prognosis, remain unclear. In this study, we established a human MDR CCA cell line QBC939/5-FU. Compared with QBC939 cells, a rounder shape, a higher nuclear-cytoplasmic ratio, a shorter cell cycle, faster growth and resistance to chemotherapeutics are major characteristics of QBC939/5-FU cells. P-glycoprotein (P-gp) and β-catenin were upregulated in QBC939/5-FU cells. Furthermore, the drug susceptibility of QBC939 cells to common chemotherapeutics was significantly decreased after Wnt3a treatment, whereas inhibition of Wnt/β-catenin pathway by β-catenin siRNA reversed the MDR of QBC939/5-FU cells to chemotherapeutics. Molecular study revealed that activation of Wnt/β-catenin pathway resulted in upregulation of P-gp and contributed to MDR of QBC939/5-FU cells. Extraction of Siamese Crocodile 3 (ESC-3) bile enhanced the drug sensitivity of QBC939/5-FU cells to 5-FU, paralleled with downregulation of β-catenin and P-gp. The association of Wnt/β-catenin pathway and P-gp was further confirmed by the clinical data for CCA tissues. Our study represents the first implication of Wnt/β-catenin activation in the MDR of CCA, which may be a beneficial target for the clinical treatment of CCA.

Oncogenic activity of retinoic acid receptor γ is exhibited through activation of the Akt/NF-κB and Wnt/β-catenin pathways in cholangiocarcinoma

Aberrant expression and function of retinoic acid receptor γ (RARγ) are often involved in the progression of several cancers. However, the role of RARγ in cholangiocarcinoma (CCA), chemoresistant bile duct carcinoma with a poor prognosis, remains unclear. In the present study, we found that RARγ was frequently overexpressed in human CCA specimens. Its overexpression was associated with poor differentiation, lymph node metastasis, high serum carbohydrate antigen 19-9 level, and poor prognosis of CCA. Downregulation of RARγ reduced CCA cell proliferation, migration, invasion, and colony formation ability in vitro and tumorigenic potential in nude mice. RARγ knockdown resulted in upregulation of cell cycle inhibitor P21, as well as downregulation of cyclin D1, proliferating cell nuclear antigen, and matrix metallopeptidase 9, in parallel with suppression of the Akt/NF-κB pathway. Furthermore, overexpression of RARγ contributed to the multidrug chemoresistance of CCA cells, at least in part due to upregulation of P glycoprotein via activation of the Wnt/β-catenin pathway. Molecular mechanism studies revealed that RARγ interacted with β-catenin and led to β-catenin nuclear translocation. Taken together, our results suggested that RARγ plays an important role in the proliferation, metastasis, and chemoresistance of CCA through simultaneous activation of the Akt/NF-κB and Wnt/β-catenin pathways, serving as a potential molecular target for CCA treatment.

Oncogenic activity of retinoic acid receptor γ is exhibited through activation of the Akt/NF-κB and Wnt/β-catenin pathways in cholangiocarcinoma

Aberrant expression and function of retinoic acid receptor γ (RARγ) are often involved in the progression of several cancers. However, the role of RARγ in cholangiocarcinoma (CCA), chemoresistant bile duct carcinoma with a poor prognosis, remains unclear. In the present study, we found that RARγ was frequently overexpressed in human CCA specimens. Its overexpression was associated with poor differentiation, lymph node metastasis, high serum carbohydrate antigen 19-9 level, and poor prognosis of CCA. Downregulation of RARγ reduced CCA cell proliferation, migration, invasion, and colony formation ability in vitro and tumorigenic potential in nude mice. RARγ knockdown resulted in upregulation of cell cycle inhibitor P21, as well as downregulation of cyclin D1, proliferating cell nuclear antigen, and matrix metallopeptidase 9, in parallel with suppression of the Akt/NF-κB pathway. Furthermore, overexpression of RARγ contributed to the multidrug chemoresistance of CCA cells, at least in part due to upregulation of P glycoprotein via activation of the Wnt/β-catenin pathway. Molecular mechanism studies revealed that RARγ interacted with β-catenin and led to β-catenin nuclear translocation. Taken together, our results suggested that RARγ plays an important role in the proliferation, metastasis, and chemoresistance of CCA through simultaneous activation of the Akt/NF-κB and Wnt/β-catenin pathways, serving as a potential molecular target for CCA treatment.

Lactobacillus plantarum surface layer adhesive protein protects intestinal epithelial cells against tight junction injury induced by enteropathogenic Escherichia coli

Lactobacillus plantarum (LP) has previously been used for the treatment and prevention of intestinal disorders and disease. However, the role of the LP surface layer adhesive protein (SLAP) in inhibition of epithelial cell disruption is not fully understood. The aim of the present study was to investigate the protective effects of purified SLAP on Caco-2 cells infected with enteropathogenic Escherichia coli (EPEC). The role of ERK in LP-mediated inhibition of tight junction (TJ) injury was also evaluated in order to determine the molecular mechanisms underlying the protective effects of LP in epithelial cells. SLAP was extracted and purified from LP cells using a porcine stomach mucin-Sepharose 4B column. SLAP-mediated inhibition of bacterial adhesion was measured using a competition-based adhesion assay. Expression of TJ-associated proteins, maintenance of TJ structure, and levels of extracellular signal regulated kinase (ERK) and ERK phosphorylation were assessed in SLAP-treated cells by a combination of real-time PCR, western blotting, and immunofluorescence microscopy. Cell permeability was analyzed by measurement of trans-epithelial electrical resistance (TER) and dextran permeability. The effect of SLAP on levels of apoptosis in epithelial cells was assessed by flow cytometry. Results from these experiments revealed that treatment with SLAP decreased the level of adhesion of EPEC to Caco-2 cells. SLAP treatment also enhanced expression of TJ proteins at both the mRNA and protein levels and affected F-actin distribution. Although ERK levels remained unchanged, ERK phosphorylation was increased by SLAP treatment. Caco-2 cells treated with SLAP exhibited increased TER and decreased macromolecular permeability, which was accompanied by a decrease in the level of apoptosis. Together, these results suggest that LP-produced SLAP protects intestinal epithelial cells from EPEC-induced injury, likely through a mechanism involving ERK activation.

Tamoxifen reverses the multi-drug-resistance of an established human cholangiocarcinoma cell line in combined chemotherapeutics

Our previous study established the human multi-drug-resistant cholangiocarcinoma cell line QBC939/ADM. In this study, we investigate further the ability of tamoxifen (TAM) to reverse drug-resistance to chemotherapeutics using QBC939/ADM cells. Cell growth inhibition was determined by the MTT assay, while cell cycle progression, apoptosis and the intra-cellular concentration of adriamycin (ADM) were all determined by flow cytometry. P-glycoprotein (P-gp) protein and mRNA expression was determined by Western blotting and real-time PCR. Growth inhibition and apoptosis induced by ADM, mitomycin (MMC), or vindesine (VDS) were enhanced after pre-treatment with 5 or 10 μM TAM, while only VDS increased cell numbers in the G(2)/M phase. The intra-cellular concentration of ADM rose after pre-treatment with 10 μM TAM, but not 5 μM TAM. Furthermore, real-time PCR and western blot analysis revealed down-regulation of P-gp expression in QBC939/ADM cells after TAM pre-treatment. The enhanced effects of TAM on growth inhibition, apoptosis, and intra-cellular concentration and the down-regulation of P-gp expression were blocked by an anti-P-gp antibody. TAM (10 μM) may reverse the multi-drug-resistance (MDR) of QBC939/ADM and enhance the chemotherapeutic effects on cholangiocarcinoma, by competitively inhibiting over-expressed P-gp.