Apoptosis In CCA Cells Research Articles

Long non-coding RNA HOTAIR promotes tumorigenesis and forecasts a poor prognosis in cholangiocarcinoma

Cholangiocarcinoma (CCA) arising from the neoplastic transformation of cholangiocytes with increasing incidence in the worldwide. Unfortunately, a large amount of CCA patients lost their chance for surgery because it is hard to diagnose in the early stages. Long non-coding RNAs (lncRNAs) is closely associated with development and progression of various malignant tumors. Hox transcript antisense intergenic (HOTAIR), a negative prognostic factor for patients with gastric, liver and pancreatic carcinoma. Its transcription levels and functional roles in CCA is still unknown. Therefore, we aimed to explore the effect of HOTAIR in CCA including cell proliferation, apoptosis, migration, invasion and epithelial-to-mesenchymal transition (EMT). The results showed that HOTAIR was highly expressed both in CCA tissue samples and cell lines compared with corresponding normal bile duct tissues and Human intrahepatic biliary epithelial cells (HIBEC). Its overexpression was closely correlated with Tumor size, TNM stage and postoperative recurrence in CCA patients. Moreover, up-regulation of HOTAIR has correlation with prognosis in CCA patients. Knockdown of HOTAIR by siRNAs significantly decreased the migration and invasion but increased apoptosis of CCA cells in vitro. Overall, our study revealed that HOTAIR may play as a new potential therapeutic target and forecast poor prognosis for this fatal disease.

Metformin facilitates BG45‑induced apoptosis via an anti‑Warburg effect in cholangiocarcinoma cells.

Cholangiocarcinoma (CCA) is a highly lethal malignancy with an often late diagnosis and consequent poor prognosis. Chemotherapy is the only therapeutic strategy for most patients. Compared to normal cells, tumor cells preferentially metabolize glucose to lactate, even in aerobic conditions. Such metabolic alterations not only support the growth and invasion of tumor cells, but also promote their chemoresistance. The purpose of our study was to explore the role of metformin in regulating the metabolism of CCA, as well as to investigate whether metformin could act as a chemosensitizer of the HDAC3 inhibitor BG45, and therefore have potential for the treatment of CCA. Through bioinformatic analysis, we found that aberrant metabolism contributed to the proliferation of CCA cells. Seahorse XF96 Extracellular Flux Analyzer analysis and lactate production analysis showed that metformin could act as a suppressor of the Warburg effect in CCA cells. Western blotting showed that metformin decreased the expression of LDHA, which plays a key role in the Warburg effect. However, suppression of the Warburg effect was not sufficient to induce CCA cellular apoptosis. According to our previous research, which showed that an HDAC3 inhibitor (MI192) was involved in CCA apoptosis, we observed that metformin combined with BG45 (a novel specific HDAC3 inhibitor) effectively induced the apoptosis of CCA cells invitro. Furthermore, invivo experiments revealed that the combined treatment with metformin and BG45 markedly reduced CCA growth in a CCA xenograft model. Our data revealed that reversing the Warburg effect with metformin sensitizes cells to the antitumor effects of HDAC3 inhibitors. This provides a rationale for using the combination of metformin and BG45 as a new therapeutic strategy in the treatment of CCA.

Phenformin inhibits cell proliferation and induces cell apoptosis and autophagy in cholangiocarcinoma.

Cholangiocarcinoma (CCA) is an aggressive malignant tumor and the prognosis of patients with advanced stage disease remains poor. Therefore, the identification of novel treatment agents for CCA is required. In the present study, the biological effects of the diabetes therapeutic agent, phenformin, in CCA cell lines was investigated. Cell Counting Kit‑8 cell viability, cellular clone formation and subcutaneous tumor formation assays were performed, which revealed that phenformin inhibited CCA cell proliferation and growth both invitro and invivo. In addition, phenformin induced CCA cell apoptosis and autophagy. Phenformin partly activated the liver kinase B1 (LKB1)/5' AMP‑activated protein kinase signaling pathway to exert its biological effects on CCA cell lines, as demonstrated by knockdown of LKB1, which reversed these effects. In conclusion, the present study demonstrated the biological effects of phenformin in CCA and suggested that phenformin may be a potential novel agent for CCA treatment.

The prognostic potential and carcinogenesis of long non-coding RNA TUG1 in human cholangiocarcinoma.

Cholangiocarcinoma (CCA) is a fatal disease with increasing worldwide incidence and is characterized by poor prognosis due to its poor response to conventional chemotherapy or radiotherapy. Long non-coding RNAs (lncRNAs) play key roles in multiple human cancers, including CCA. Cancer progression related lncRNA taurine-up-regulated gene 1 (TUG1) was reported to be involved in human carcinomas. However, the impact of TUG1 in CCA is unclear. The aim of this study was to explore the expression pattern of TUG1 and evaluate its clinical significance as well as prognostic potential in CCA. In addition, the functional roles of TUG1 including cell proliferation, apoptosis, migration, invasion and epithelial-mesenchymal transition (EMT), were evaluated after TUG1 silencing. Our data demonstrated up-regulation of TUG1 in both CCA tissues and cell lines. Moreover, overexpression of TUG1 is linked to tumor size (p=0.005), TNM stage (p=0.013), postoperative recurrence (p=0.036) and overall survival (p=0.010) of CCA patients. Furthermore, down-regulation of TUG1 following RNA silencing reduced cell growth and increased apoptosis in CCA cells. Additionally, TUG1 suppression inhibited metastasis potential in vitro by reversing EMT. Overall, our results suggest that TUG1 may be a rational CCA-related prognostic factor and therapeutic target.

Upregulated long noncoding RNA PANDAR predicts an unfavorable prognosis and promotes tumorigenesis in cholangiocarcinoma.

Cholangiocarcinoma (CCA) is one of the most malignant human cancers with increasing incidence worldwide. LncRNAs have emerged as gene regulators and prognostic biomarkers in a variety of neoplasms. PANDAR, a novel cancer-related lncRNA, has been reported to be upregulated in diverse human carcinomas. In this study, we aimed to investigate the clinical significance of lncRNA PANDAR in CCA and explore its functional roles in CCA cells including cell proliferation, apoptosis, migration, invasion and epithelial-to-mesenchymal transition (EMT). The results showed that PANDAR was significantly upregulated in CCA tissue specimens and cell lines, and its high expression was closely associated with lymph node invasion (P=0.004), TNM stage (P=0.034) and postoperative relapse (P=0.006) in patients with CCA. Thus, overexpression of PANDAR could serve as an independent prognostic biomarker of CCA. Furthermore, silencing of PANDAR followed by siRNA significantly inhibited cell proliferation and increased apoptosis in CCA cells. In addition, suppression of PANDAR impaired migration and invasion capacity in vitro partly by affecting EMT. Overall, our findings showed that lncRNA PANDAR serves as a novel prognostic biomarker and therapeutic target for CCA.

Cryptotanshinone induces cell cycle arrest and apoptosis through the JAK2/STAT3 and PI3K/Akt/NFκB pathways in cholangiocarcinoma cells.

BackgroundCholangiocarcinoma (CCA) is the most common biliary tract malignancy in the world with high resistance to current chemotherapies and extremely poor prognosis. The main objective of this study was to investigate the inhibitory effects of cryptotanshinone (CTS), a natural compound isolated from Salvia miltiorrhiza Bunge, on CCA both in vitro and in vivo and to explore the underlying mechanisms of CTS-induced apoptosis and cell cycle arrest.MethodsThe anti-tumor activity of CTS on HCCC-9810 and RBE cells was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay and colony forming assays. Cell cycle changes were detected by flow cytometric analysis. Apoptosis was detected by annexin V/propidium iodide double staining and Hoechst 33342 staining assays. The efficacy of CTS in vivo was evaluated using a HCCC-9810 xenograft model in athymic nude mice. The expression of key proteins involved in cell apoptosis and signaling pathway in vitro was analyzed by Western blot analysis.ResultsCTS induced potent growth inhibition, S-phase arrest, apoptosis, and colony-forming inhibition in HCCC-9810 and RBE cells in a dose-dependent manner. Intraperitoneal injection of CTS (0, 10, or 25 mg/kg) for 4 weeks significantly inhibited the growth of HCCC-9810 xenografts in athymic nude mice. CTS treatment induced S-phase arrest with a decrease of cyclin A1 and an increase of cyclin D1 protein level. Bcl-2 expression was downregulated remarkably, while Bax expression was increased after apoptosis occurred. Additionally, the activation of JAK2/STAT3 and PI3K/Akt/NFκB was significantly inhibited in CTS-treated CCA cells.ConclusionCTS induced CCA cell apoptosis by suppressing both the JAK2/STAT3 and PI3K/Akt/NFκB signaling pathways and altering the expression of Bcl-2/Bax family, which was regulated by these two signaling pathways. CTS may serve as a potential therapeutic agent for CCA.

Targeting SHP-1-STAT3 signaling: A promising therapeutic approach for the treatment of cholangiocarcinoma.

Sorafenib is a multiple kinase inhibitor which targets Raf kinases, VEGFR, and PDGFR and is approved for the treatment of hepatocellular carcinoma (HCC). Previously, we found that p-STAT3 is a major target of SC-43, a sorafenib derivative. In this study, we report that SC-43-induced apoptosis in cholangiocarcinoma (CCA) via a novel mechanism. Three CCA cell lines (HuCCT-1, KKU-100 and CGCCA) were treated with SC-43 to determine their sensitivity to SC-43-induced cell death and apoptosis. We found that SC-43 activated SH2 domain-containing phosphatase 1 (SHP-1) activity, leading to p-STAT3 and downstream cyclin B1 and Cdc2 downregulation, which induced G2-M arrest and apoptotic cell death. Importantly, SC-43 augmented SHP-1 activity by direct binding to N-SH2 and relief of its autoinhibition. Deletion of the N-SH2 domain (dN1) or point mutation (D61A) of SHP-1 counteracted the effect of SC-43-induced SHP-1 phosphatase activation and antiproliferation ability in CCA cells. In vivo assay revealed that SC-43 exhibited xenograft tumor growth inhibition, p-STAT3 reduction and SHP-1 activity elevation. In conclusion, SC-43 induced apoptosis in CCA cells through the SHP-1/STAT3 signaling pathway.

Repurposing cimetidine for cholangiocarcinoma: Antitumor effects in vitro and in vivo.

Cimetidine is a histamine type-2 (H2) receptor antagonist that has been demonstrated to have antitumor effects on various types of malignancy. However, its effect on cholangiocarcinoma (CCA), a chemotherapy-resistant bile duct tumor, has yet to be investigated. In the present study, the antitumor activity of cimetidine in vitro and in vivo was evaluated. A methylthiotetrazole assay revealed that the proliferation of certain CCA cell lines was inhibited by cimetidine, which induced the caspase-dependent apoptosis of CCA cells via suppression of the protein kinase B signaling pathway. Suppression of Akt phosphorylation, caspase-3, -8 and -9 activation, phosphotidylserine exposure determined by Annexin V binding assay and the presence of a sub-G1 population were demonstrated by western blotting and flow cytometry analysis. In a CCA xenograft mouse model cimetidine inhibited the growth of CCA cells without observable adverse effects. These results suggest that cimetidine has the potential to be an effective antitumor agent for the treatment of CCA.

TRAIL Enhances Shikonin Induced Apoptosis through ROS/JNK Signaling in Cholangiocarcinoma Cells

Background/Aims: Cholangiocarcinoma (CCA), arising from varying locations within the biliary tree, is the second most common primary liver malignancy worldwide. Shikonin, an active compound extracted from the Chinese herb Zicao, holds anti-bacterial, anti-inflammatory, and anti-tumor activities. However, the effect of shikonin on human cholangiocarcinoma and detailed mechanisms of TRAIL enhancement remains to be elucidated. The purpose of the study was to investigate the protective functions of TRAIL enhancement for shikonin induced apoptosis in cholangiocarcinoma cells. Methods: We use MTT assay, apoptosis assay, caspase activity assay, flow cytometry assay, real time PCR and Western blot to observe the effects of TRAIL on shikonin induced cholangiocarcinoma cells apoptosis and its mechanism. Results: Shikonin inhibited cell viability and induced apoptosis of CCA cells, effects enhanced by TRAIL treatment via activation of caspase-3, -8, -9. Furhermore, TRAIL enhanced anti-proliferation of shikonin and shikonin induced apoptosis through induction of ROS mediated JNK activation, while AKT activation had an effect on shikonin anti-proliferation activity, but not in the TRAIL enhanced counterparts. Finally, shikonin upregulated DR5 expression, an effect essential for TRAIL-enhanced activities of shikonin in RBE cells. Conclusions: Our results revealed that shikonin could inhibit cells viability and induce apoptosis of CCA cells, effects enhanced by TRAIL treatment via ROS mediated JNK signalling pathways, involving up-regulation of DR5 expression. Our results provide further insight into the mechanism underlying the anti-tumor effects of shikonin by TRAIL enhanced in CCA and a new therapeutic strategy to CCA treatment.

Upregulated LASP-1 correlates with a malignant phenotype and its potential therapeutic role in human cholangiocarcinoma.

LIM and SH3 protein 1 (LASP-1) is demonstrated to play a key role in occurrence and development of tumors. However, the expression and function of LASP-1 in cholangiocarcinoma (CCA) remain largely unexplored. This study aimed to investigate the effect of regulated LASP-1 expression on migration, invasion, proliferation, and apoptosis of CCA cells and on tumorigenesis in vivo, and to examine clinico-oncological correlates of LASP-1 expression. Expression of LASP-1 by immunohistochemistry was evaluated in CCA tissue samples. HCCC-9810 and RBE cells were transfected with the LASP-1 small interfering RNA (siRNA), and the effect of knocking down LASP-1 gene expression on cell migration, invasion, proliferation, and apoptosis were examined by wound healing, transwell assays, CCK-8 assays, colony formation, and flow cytometry assays, respectively. Xenograft tumor model was used to validate the effect of downregulated LASP-1 in vivo. Our results demonstrated that LASP-1 was over-expressed in CCA tissues, positively correlating with larger tumors, poor histological differentiation, lymph node metastasis, advanced TNM stage, and poor prognosis in CCA patients (P < 0.05). Downregulation of LASP-1 in HCCC-9810 and RBE cell lines significantly increased cell apoptosis and suppressed cell migration, invasion, and proliferation in vitro and tumorigenesis in vivo. Our results indicate that LASP-1 may essentially involve in the metastasis and growth of CCA and clinical significance of LASP-1 may reside in function as a biomarker to predict prognosis and as a promising therapeutic strategy for CCA patients by the inhibition of LASP-1 expression.

TRAIL in Combination with Subtoxic 5-FU Effectively Inhibit Cell Proliferation and Induce Apoptosis in Cholangiocarcinoma Cells.

In the past decade, the incidence and mortality rates of cholangiocarcinoma (CCA) have been increasing worldwide. The relatively low responsiveness of CCA to conventional chemotherapy leads to poor overall survival. Recently, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL or Apo2L) has emerged as the most promising anti-cancer therapeutic agent since it is able to selectively induce apoptosis of tumor cells but not normal cells. In this study, we aimed to investigate the therapeutic effect of TRAIL in CCA cell lines (M213, M214 and KKU100) compared with the immortal biliary cell line, MMNK1, either alone or in combination with a subtoxic dose of 5-fluorouracil (5-FU). We found that recombinant human TRAIL (rhTRAIL) was a potential agent which significantly inhibited cell proliferation and mediated caspase activities (caspases 8, 9 and 3/7) and apoptosis of CCA cells. The combined treatment of rhTRAIL and 5-FU effectively enhanced inhibition of CCA cell growth with a smaller effect on MMNK1. Our finding suggests TRAIL to be a novel anti-cancer therapeutic agent and advantage of its combination with a conventional chemotherapeutic drug for effective treatment of CCA.

Significance of S100P as a biomarker in diagnosis, prognosis and therapy of opisthorchiasis-associated cholangiocarcinoma.

Cholangiocarcinoma (CCA) is a malignancy of bile duct with the difficulty in early diagnosis, poor prognosis and less alternation in therapy. S100P is a member of S100 family proteins and plays important roles in cancers. We investigated the S100P expression and its correlation with clinicopathology in 78 cases of opisthorchiasis-associated CCA, and the effects of S100P knockdown with shRNA interference on the proliferation, cell cycle, migration, apoptosis and sensitivity to anti-cancer drug. Extremely high expression of S100P mRNA was detected in the CCA tumor tissues. The increased S100P protein expression was immunohistochemically confirmed and localized in the CCA cytoplasm and/or nuclei as well as in the hyperneoplasia and dysplasia bile ducts, but not in normal bile ducts. The intensity of immunostaining was correlated with survival, tumor stage and metastasis, and the high expression could be an independent prognostic factor. High levels of S100P were detected in the serum and bile fluid of CCA patients. The shRNA-mediated knockdown of S100P expression inhibited the proliferation in vitro and in vivo, and migration of CCA cells, arrested cell cycle with the up-regulated expression of cell cycle arrest related factors, p21, p27, GADD45A, and 14-3-3 zeta. S100P knockdown also promoted CCA cell apoptosis by up-regulating expression of apoptosis related factors, DR5, TRADD, caspase 3 and BAX, and increased the sensitivity of CCA cells to the chemotherapeutic agents sunitinib and apigenin. Taken together, this study indicates that S100P might be a promising biomarker for the diagnosis, prognosis and therapy of CCA.

Generation of cancer-specific CD8+ CD69+ cells inhibits colon cancer growth

The therapy of colon cancer (Cca) is poor currently. The abnormality of immune function is recognized in cancer-bearing hosts. This study aims to inhibit Cca growth with the in vivo induction of Cca-specific CD8+ CD69+ T cell polarization. In this study, a mouse tumor model was created with a mouse colon cancer (Cca) cell line. The Cca-bearing mice were immunized with Cca extracts and alum (using as an adjuvant). The CD8+ CD69+ cell polarization status was analyzed by flow cytometry and enzyme-linked immunosorbent assay. The results showed that a Cca antigen-specific CD8+ CD69+ cells were induced in the Cca-bearing mice. The Cca growth was efficiently inhibited by the Cca-specific CD8+ CD69+ cell response. The Cca-specific CD8+ CD69+ cells were detected in the Cca mass and spleen, which had the ability to induce Cca cell apoptosis. In conclusion, the Cca-specific CD8+ CD69+ cell polarization can be induced in Cca-bearing mice, which can efficiently inhibit the Cca growth.

Tumor-specific Th2 responses inhibit growth of CT26 colon-cancer cells in mice via converting intratumor regulatory T cells to Th9 cells.

The abnormality of immune regulation plays a critical role in the pathogenesis of cancer; the underlying mechanism has not been fully understood yet. This study aims to investigate the role of cancer specific T helper (Th)2 response in the inhibition of colon cancer (Cca) cell growth. The results showed that with Cca cell (CT26 cell) extracts as an antigen, the Cca-extract specific Th2 response was induced in the Cca-bearing mice. The Cca mass size was significantly reduced, or radically disappeared (5 out of 10; or 50%); the survival rate was markedly improved in mice immunized with Cca-extract, but not in those immunized with another tumor cell (U87 cell) extracts or to bovine serum albumin. The immunization with Cca-extract also induced Cca cell apoptosis and converted the intra-Cca Tregs to T helper (Th) 9 cells. In conclusion, Cca-specific Th2 responses inhibit Cca growth in a mouse model via inducing Cca cell apoptosis and converting intra-Cca Tregs to Th9 cells.

Fibroblast growth factor receptor 4 promotes progression and correlates to poor prognosis in cholangiocarcinoma

Fibroblast growth factor receptor 4 (FGFR4) is related to poor prognosis of several cancers, but the correlation between FGFR4 expression and cholangiocarcinoma (CCA) has not been well elucidated. We investigated the expression of FGFR4 in 83 intrahepatic cholangiocarcinomas (IHCCs), 75 perihilar cholangiocarcinomas (PHCCs) and 41 distal cholangiocarcinomas (DCCs) by immunohistochemistry (IHC), and subsequently evaluated association of FGFR4 with clinicopathologic parameters and survival rate. The rate of FGFR4 higher expression was 61.4% (51/83) in IHCCs, 53.3% (40/75) in PHCCs and 56.1% (23/41) in DCCs. FGFR4 expression was significantly related to poor prognosis of IHCC (P=0.002) and PHCC (P=0.019) with univariate analysis, and also identified as an independent prognostic factor in IHCC (P=0.045) and PHCC (P=0.049) with multivariate analysis. Additionally, with functional assays in vitro, we found FGFR4 can induce proliferation, invasion and epithelial–mesenchymal transition (EMT) of CCA cell lines with FGF19 stimulation. Moreover, FGFR4 inhibitor AP24354 can suppress proliferation, invasion and induce apoptosis of CCA cells. In conclusion, FGFR4 expression can be identified as a significant independent prognostic biomarker of IHCC and PHCC. FGFR4 played a pivotal role in proliferation, invasion and EMT of CCA. FGFR4 inhibitor can suppress proliferation, invasion and induce apoptosis of CCA, indicating that FGFR4 may act as a potential therapeutic target.

Polo-like kinase 2 is a mediator of hedgehog survival signaling in cholangiocarcinoma.

Cholangiocarcinoma (CCA) cells paradoxically express the death ligand tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and thus rely on potent survival signals to circumvent cell death by TRAIL. Hedgehog (Hh) signaling is an important survival pathway in CCA. Herein, we further examine the mechanisms whereby Hh signaling mediates apoptosis resistance in CCA, revealing a pivotal role for the cell division regulating serine/threonine kinase polo-like kinase 2 (PLK2). We employed 50 human CCA samples (25 intrahepatic and 25 extrahepatic CCA) as well as human KMCH-1, Mz-CHA-1, and HUCCT-1 CCA cells for these studies. In vivo experiments were conducted using a syngeneic rat orthotopic CCA model. In human samples, polo-like kinase (PLK)1/2/3-immunoreactive cancer cells were present in the preponderance of intra- and extrahepatic CCA specimens. Inhibition of Hh signaling by cyclopamine reduced PLK2, but not PLK1 or PLK3, messenger RNA and protein expression in vehicle-treated and sonic Hh-treated CCA cells, confirming our previous microarray study. PLK2 regulation by Hh signaling appears to be direct, because the Hh transcription factors, glioma-associated oncogene 1 and 2, bind to the PLK2 promotor. Moreover, inhibition of PLK2 by the PLK inhibitor, BI 6727 (volasertib), or PLK2 knockdown was proapoptotic in CCA cells. BI 6727 administration or PLK2 knockdown decreased cellular protein levels of antiapoptotic myeloid cell leukemia 1 (Mcl-1), an effect reversed by the proteasome inhibitor, MG-132. Finally, BI 6727 administration reduced Mcl-1 protein expression in CCA cells, resulting in CCA cell apoptosis and tumor suppression in vivo. PLK2 appears to be an important mediator of Hh survival signaling. These results suggest PLK inhibitors to be of therapeutic value for treatment of human CCA.

The heat shock protein 90 inhibitor 17-AAG suppresses growth and induces apoptosis in human cholangiocarcinoma cells

The aim of this study was to investigate the effects of 17-Allylamino-17-demethoxygeldanamycin (17-AAG), a heat shock protein 90 (HSP90) inhibitor, on the proliferation, cell cycle, and apoptosis of human cholangiocarcinoma (CCA) cells. Cell proliferation and cell cycle distribution were measured by the MTT assay and flow cytometry analysis, respectively. Induction of apoptosis was determined by flow cytometry and Hoechst staining. The expressions of cleaved poly ADP-ribose polymerase (PARP), Bcl-2, Survivin, and Cyclin B1 were detected by Western blot analysis. The activity of caspase-3 was also examined. We found that 17-AAG inhibited cell growth and induced G2/M cell cycle arrest and apoptosis in CCA cells together with the down-regulation of Bcl-2, Survivin and Cyclin B1, and the up-regulation of cleaved PARP. Moreover, increased caspase-3 activity was also observed in CCA cells treated with 17-AAG. In conclusion, our data suggest that the inhibition of HSP90 function by 17-AAG may provide a promising therapeutic strategy for the treatment of human CCA.

Lobaplatin induces apoptosis and arrests cell cycle progression in human cholangiocarcinoma cell line RBE

The aim of this study was to determine the anticancer effects of lobaplatin in cholangiocarcinoma (CCA) RBE cells. We also explored the mechanism of action of lobaplatin by analyzing its influence on apoptosis and cell cycle. Our findings have shown that lobaplatin inhibits cell proliferations in human CCA cells with an IC50 value of approximately 5.26±0.63 μg/mL. Flowcytometry assay confirmed that lobaplatin affected CCA cell survival by blocking cell cycle progression and inducing apoptosis. Lobaplatin treatment reduced Cyclin D1, CDK4, and CDK6 expression, which led to the blocking of G0/G1 transition. In addition, lobaplatin increased p53, Bax expression, caspase-3 and poly (ADP-ribose) polymerase (PARP) cleavage, and reduced Bcl-2 expression, which contributed to the apoptosis of CCA cells. Lobaplatin showed a good anti-tumour activity in in vitro models of human CCA cells. These results indicate that Lobaplatin, as the third-generation platinum antineoplastic agent, could be an effective chemotherapeutic agent in human CCA treatment through induction apoptosis and cell cycle arrest.

Targeting PDGFR‐β in Cholangiocarcinoma

Cholangiocarcinomas (CCAs) are highly desmoplastic neoplasms with a tumour microenvironment plentiful in myofibroblasts (MFBs). MFB-derived PDGF-BB survival signalling is a mediator of CCA cell resistance to apoptotic stimuli. This raises the concept that targeting PDGFR-β, a cognate receptor of PDGF-BB, represents a potential strategy for the treatment of human CCA. Herein, we examine a role for inhibiting PDGFR-β in restoring CCA cell sensitivity to apoptotic stimuli invitro and in vivo. We employed human CCA samples from 41 patients (19 intrahepatic and 22 extrahepatic CCA samples), the human CCA cell lines KMCH-1 and HUCCT-1 as well as shPDGFR-β-KMCH-1 and human myofibroblastic LX-2 cells for these studies. In vivo-experiments were conducted using a syngeneic rat orthotopic CCA model. Of several MFB-derived growth factors profiled, PDGF-BB and CTGF were most abundantly expressed; however, only PDGF-BB attenuated tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) cytotoxicity. Co-culturing CCA cells with PDGF-BB-secreting MFBs significantly decreased TRAIL-induced CCA cell apoptosis when compared with monoculture conditions; this cytoprotective effect was abrogated in the presence of the tyrosine kinase inhibitors imatinib mesylate or linifanib, which inhibit PDGFR-β. Consistent with these findings, MFB-imparted cytoprotection also was abolished when PDGFR-β was knocked down as demonstrated in shPDGFR-β-KMCH-1 cells. Finally, administration of imatinib mesylate increased CCA cell apoptosis and reduced tumour growth in a rodent in vivo-CCA model that mimics the human disease. Targeting PDGFR-β sensitizes CCA cells to apoptotic stimuli and appears to be therapeutic in vivo.

Myofibroblast-derived PDGF-BB promotes hedgehog survival signaling in cholangiocarcinoma cells

Cholangiocarcinoma (CCA) cells paradoxically express the death ligand, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and, therefore, are dependent upon potent survival signals to circumvent TRAIL cytotoxicity. CCAs are also highly desmoplastic cancers with a tumor microenvironment rich in myofibroblasts (MFBs). Herein, we examine a role for MFB-derived CCA survival signals. We employed human KMCH-1, KMBC, HuCCT-1, TFK-1, and Mz-ChA-1 CCA cells, as well as human primary hepatic stellate and myofibroblastic LX-2 cells, for these studies. In vivo experiments were conducted using a syngeneic rat orthotopic CCA model. Coculturing CCA cells with myofibroblastic human primary hepatic stellate cells or LX-2 cells significantly decreased TRAIL-induced apoptosis in CCA cells, a cytoprotective effect abrogated by neutralizing platelet-derived growth factor (PDGF)-BB antiserum. Cytoprotection by PDGF-BB was dependent upon Hedgehog (Hh) signaling, because it was abolished by the smoothened (SMO; the transducer of Hh signaling) inhibitor, cyclopamine. PDGF-BB induced cyclic adenosine monophosphate-dependent protein kinase-dependent trafficking of SMO to the plasma membrane, resulting in glioma-associated oncogene (GLI)2 nuclear translocation and activation of a consensus GLI reporter gene-based luciferase assay. A genome-wide messenger RNA expression analysis identified 67 target genes to be commonly up- (50 genes) or down-regulated (17 genes) by both Sonic hedgehog and PDGF-BB in a cyclopamine-dependent manner in CCA cells. Finally, in a rodent CCA in vivo model, cyclopamine administration increased apoptosis in CCA cells, resulting in tumor suppression. MFB-derived PDGF-BB protects CCA cells from TRAIL cytotoxicity by a Hh-signaling-dependent process. These results have therapeutical implications for the treatment of human CCA.