Suyanee Thongchot

Urinary microRNA-192 and microRNA-21 as potential indicators for liver fluke-associated cholangiocarcinoma risk group.

Opisthorchis viverrini infection induces chronic inflammation in the bile ducts, leading to periductal fibrosis (PDF), which possibly associates to cholangiocarcinoma (CCA). Patients with CCA have a poor prognosis, which is linked to asymptomatic disease and late diagnosis. Hence, detecting early stage CCA is essential. Secretory miRNAs have been promoted as biomarkers for pathological changes associated with parasitic infections, fibrosis and/or cancer. We aimed to determine levels of miR-192 and miR-21 in the urine of O. viverrini infected, periductal fibrosis (PDF) and CCA groups using qRT-PCR. We found that miR-192 was significantly higher in O. viverrini infected, PDF and also CCA groups (p<0.05) than in healthy controls. By utilizing the Receiver Operation Characteristics (ROC) analysis, miR-192 differentiated patients with opisthorchiasis (the area under the curve; AUC=0.766), PDF subjects (AUC=0.781) and CCA patients (AUC=0.682) from healthy controls. MiR-21 was significantly higher in PDF and CCA groups (p<0.05) than in healthy controls. MiR-21 discriminated PDF subjects (AUC=0.735) and CCA patients (AUC=0.682) from healthy controls. Combined levels of these two miRNAs revealed an increased AUC of 0.812 for separating opisthorchiasis, AUC of 0.815 in discriminating PDF subjects, and AUC of 0.849 in differentiating CCA from healthy controls. Odds ratios (OR) indicated high levels of miR-192/miR-21 as risk predictors for opisthorchiasis, PDF and CCA. Levels of these miRNAs declined significantly for patients following praziquantel treatment. In conclusion, urinary miR-192/miR-21 have potential as risk indicators for opisthorchiasis and PDF-associated CCA in the endemic region.

High Expression of HIF-1α, BNIP3 and PI3KC3: Hypoxia-Induced Autophagy Predicts Cholangiocarcinoma Survival and Metastasis

Hypoxia and autophagy are known to facilitate tumor progression. We here aimed to investigate the role of hypoxia-associated autophagy in cholangiocarcinoma (CCA) survival and metastasis. Immunostaining of hypoxic- responsive proteins (HIF-1α and BNIP3) and a key regulator of autophagy (PI3KC3) were examined in CCA tissues and their expression levels were compared with clinicopathological parameters. A hypoxia mimicking condition (CoCl2 treatment) was also tested regarding CCA cell functions. Our results showed that HIF-1α (66%), BNIP3 (44%) and PI3KC3 (46%) showed strong staining in human CCA tissues. Positive expression of HIF-1α (p=0.033), BNIP3 (p=0.040) and PI3KC3 (p=0.037) was significantly correlated with lymph node metastasis. HIF-1α was well associated with BNIP3 (r=0.3, p<0.01) and PI3KC3 (r=0.2, p<0.01). The survival rates of patients who were positive with HIF-1α (p=0.047) or co-expressed HIF-1α and BNIP3 (p=0.032) or HIF-1α and PI3KC3 (p=0.043) were significantly greater than in the negative groups. CCA cells treated with CoCl2 showed an increase in HIF-1α, BNIP3, PI3KC3 and LC3-II, with increased cell migration and pFAK levels. These data suggest that hypoxia associated autophagy enhances CCA metastasis, resulting in a poor prognosis of CCA.

Resveratrol interrupts the pro-invasive communication between cancer associated fibroblasts and cholangiocarcinoma cells

Cholangiocarcinoma (CCA), the cancer arising from the epithelial cells of bile ducts, is a prototype of inflammatory-driven cancer. Cytokines released by cancer associated fibroblasts (CAFs) play a pivotal role in CCA progression, driving the epigenetic Epithelial-to-Mesenchymal transition and the growth and metastasization of CCA cells. Consistently, the conditioned medium from CCA-derived CAFs further stimulated the secretion of IL-6, and to a lesser extent of IL-8, by CCA cells. CCA has a poor prognosis, because of late diagnosis and of high resistance to radio- and chemo-therapy of CCA cells. Targeting the CAFs and their secretion could be an alternative option. We found that while IL-6 indeed promoted the cell migration of invasive CCA cells, the nutraceutical Resveratrol strongly counteracted this effect both in CCA cells and in immortalized cholangiocytes. More importantly, here we show that Resveratrol has the potential to abrogate the secretion of IL-6 by CAFs. While the conditioned medium from CAFs strongly induced IL-6 mediated motility of CCA cells, the conditioned medium from CAFs pre-treated with Resveratrol completely halted cancer cell motility and reverted the N-to E-cadherin switch in migrating cells. This effect was associated with stimulation of autophagy in the cancer cells. This is the first demonstration that CAFs secretory products directly affect the regulation of autophagy and consequently the behavior of CCA cells, and that a nutraceutical may revert the malignant phenotype of cancer cells by acting on CAFs metabolism and secretion.

Potential role of HIF-1-responsive microRNA210/HIF3 axis on gemcitabine resistance in cholangiocarcinoma cells

MicroRNA-210 (miR-210) is a robust target for hypoxia-inducible factor, and its overexpression has been detected in a variety of solid tumors. However, the role of miR-210 in the development, progression and response to therapy in cholangiocarcinoma (CCA) remains undefined. We report here that high miR-210 expression was significantly correlated with the shorter survival of CCA patients. Overexpression of miR-210 inhibited CCA cell proliferation at the G2/M phase and reduced the gemcitabine sensitivity in CCA cells under CoCl2-induced pseudohypoxia. Concomitantly, inhibition of endogenous miR-210 activity using miRNA sponges increased cell proliferation under CoCl2-induced pseudohypoxia, resulting in an increase in gemcitabine sensitivity in CCA cells. We showed that HIF-3α, a negative controller of HIF-1α, was a target of miR-210 constituting a feed-forward hypoxic regulatory loop. Our data suggest an important role of miR-210 in sustaining HIF-1α activity via the suppression of HIF-3α, regulating cell growth and chemotherapeutic drug resistance in CCA.

Dihydroartemisinin induces apoptosis and autophagy-dependent cell death in cholangiocarcinoma through a DAPK1-BECLIN1 pathway

Cholangiocarcinoma (CCA) is a very aggressive cancer arising from the malignant transformation of cholangiocytes. Intrahepatic CCA is associated with reactive inflammation and intense fibrosis of the hepatobiliary tract. Dihydroartemisinin (DHA), the active compound found in Artemisia annua, has been shown to possess anti‐tumor activity in a variety of human cancers, including hepatoma. Here, we tested the ability of DHA to specifically kill CCA cells and have investigated the underlying mechanisms. DHA induced both apoptosis and autophagy‐dependent caspase‐independent cell death in many CCA cell lines, while being slightly toxic to immortalized cholangiocytes. DHA induced the expression of many apoptosis‐ and autophagy‐related genes in CCA cells. In particular, it greatly induced the expression of DAPK1, and reduced the interaction of BECLIN1 with BCL‐2 while promoting its interaction with PI3KC3. Genetic silencing of DAPK1 prevented DHA‐induced autophagy. Pharmacologic and genetic inhibition of BECLIN1 function prevented autophagy and cell death induced by DHA in CCA cells. These data unravel a novel pathway of DHA cancer toxicity and open the possibility to introduce DHA in the therapeutic regimen for the treatment of CCA.

Suppression of 14-3-3ζ in cholangiocarcinoma cells inhibits proliferation through attenuated Akt activity, enhancing chemosensitivity to gemcitabine

The protein 14-3-3ζ contributes important regulatory functions in several cellular processes via binding to phosphorylated serine/threonine residues, which promotes cell cycle progression, cell proliferation and anti-apoptosis in multiple types of cancer. The aim of the present study was to investigate the functions of 14-3-3ζ in cholangiocarcinoma (CCA) progression and elucidate the molecular mechanism of 14-3-3ζ expression-mediated protein kinase B (Akt) phosphorylation and chemosensitivity in CCA cells. In the present study, 14-3-3ζ expression was investigated in clinical specimens using immunohistochemistry and compared with the clinicopathological features of patients with CCA. The association between 14-3-3ζ and phosphorylated Akt (pAkt) was determined among the tissues of the same patients using bivariate correlation analysis. The effects of 14-3-3ζ suppression on CCA cell function and gemcitabine sensitivity were investigated using small interfering RNA (siRNA). It was identified that 14-3-3ζ expression was positively correlated with pAkt (P=0.013) and that increased expression of 14-3-3ζ and pAkt were significantly associated with poor overall survival rate and metastasis (P=0.025 and 0.006, respectively). Downregulation of 14-3-3ζ using siRNA in CCA cell lines decreased cell proliferation, resulting in the inhibition of pAkt activity and increasing the protein level of the cell cycle inhibitor p27. The suppression of 14-3-3ζ enhanced the inhibitory effect of gemcitabine on CCA cell proliferation by inducing apoptotic cell death. Taken together, the results of the present study indicated that 14-3-3ζ is a potential target for CCA and may serve as a novel therapeutic approach to enhance chemosensitivity in the treatment of CCA.

Upregulation of TCTP is associated with cholangiocarcinoma progression and metastasis

In order to investigate the role of translationally-controlled tumor protein (TCTP) in cholangiocarcinoma (CCA) progression and metastasis, TCTP protein staining in paraffin-embedded sections of human CCA tissue samples was examined using immunohistochemistry, and its expression was subsequently compared with clinicopathological parameters. Small interfering RNA (siRNA) targeting TCTP (siTCTP) were transfected into CCA cell lines to evaluate its effects on cellular functions. The proliferation, tumorigenicity and migration abilities of the transfected cells were measured using sulforhodamine B, clonogenic and would healing assays, respectively. The protein levels of TCTP and its associated molecules were evaluated by western blot analysis. Of the 119 individual cases of CCA tissues analyzed, high TCTP scores were significantly correlated with overall metastasis (P=0.044) and a shorter survival time (P<0.001). Multivariate proportional hazards analysis revealed that TCTP is an independent indicator of poor prognosis in CCA (hazard ratio =2.864; P<0.001). siTCTP transfection suppressed CCA cell growth and migration abilities, compared with the control cells (P<0.01). The siTCTP reduced the protein levels of focal adhesion kinase (FAK), phospho-FAK, nuclear factor kappa-light-chain-enhancer of activated B cells and matrix metalloproteinase 9, suggesting potential roles of TCTP in regulating CCA progression and metastasis. In conclusion, the upregulation of TCTP is clinically significant in patients with CCA, serving roles in CCA progression, particularly in cell survival and metastasis. Suppression of TCTP may serve as a potential target in CCA prevention and treatment.