Induction of apoptotic cell death of cholangiocarcinoma cells by tiliacorinine from Tiliacora triandra: A mechanistic insight.

BACKGROUND: Cholangiocarcinoma (CCA) exhibits poor response to the present chemotherapeutic agents and frequently develops drug resistance. Finding novel anticancer drugs might enhance patient outcomes. Tiliacorinine, a bisbenzylisoquinoline alkaloid from the Thai medicinal plant Tiliacora triandra, effectively induced apoptosis of human CCA cell lines and inhibited tumor growth in mice. Here, we elucidate further the molecular mechanisms underlining the cytotoxicity of tiliacorinine and its implication in overcoming gemcitabine-resistance of CCA cells. METHODS: Cytotoxicity of tiliacorinine against CCA cell lines was assessed using MTT assay. The molecular signaling was determined using Western blot analysis. Molecular docking simulations were applied to predict the binding affinity and orientation of tiliacorinine to the possible binding site(s) of the target proteins. RESULTS: Tiliacorinine induced apoptotic cell death of CCA cells in a dose- and time-dependent manner. Tiliacorinine significantly suppressed the expression of anti-apoptotic proteins, Bcl-xL and XIAP; activated apoptotic machinery proteins, caspase-3, caspase-9, and PARP; and decreased the levels of pAkt and pSTAT3. EGF/EGFR activation model and molecular docking simulations revealed EGFR, Akt, and STAT3 as potent targets of tiliacorinine. Molecular docking simulations indicated a strong binding affinity of tiliacorinine to the ATP-binding pockets of EGFR, PI3K, Akt, JAK2, and SH2 domain of STAT3. Tiliacorinine could synergize with gemcitabine and restore the cytotoxicity of gemcitabine against gemcitabine-resistant CCA cells. CONCLUSION: Tiliacorinine effectively induced apoptosis via binding and blocking the actions of EGFR, Akt, and STAT3. GENERAL SIGNIFICANCE: Tiliacorinine is a novel multi-kinase inhibitor and possibly a potent anti-cancer agent, in cancers with high activation of EGFR.

BI6727 and GSK461364A, potent PLK1 inhibitors induce G2/M arrest and apoptosis against cholangiocarcinoma cell lines.

Polo-like kinase 1 (PLK1) is an essential mitotic checkpoint protein that plays a key role in cell cycle division. Overexpression of PLK1 has been associated with poor prognosis in various cancers. Cholangiocarcinoma (CCA) is a lethal bile duct cancer and the current treatments in inoperable patients have not been satisfactory. In order to develop novel targeted therapies, we investigated the efficacy of BI6727 (volasertib) and GSK461364A, polo-like kinase 1 (PLK1) inhibitors in KKU-100 and KKU-213A CCA cell lines. PLK1 expression was significantly up-regulated in CCA cases compared with normal tissues based on the results derived from GEPIA. Western blot results exhibited PLK1 protein expression in both CCA cell lines. Molecular dynamics simulations and free energy calculations based on MM/GBSA method revealed that BI6727-PLK1 and GSK461364A-PLK1 complexes were stable in an aqueous environment, and their complexation was mainly driven by Van der Waals interaction. BI6727 and GSK461364A clearly suppressed CCA cell proliferation and induced G2/M arrest, accompanied with upregulation of cyclin B1 and phosphorylated Histone H3 at Ser10 (pS10H3), specific markers of mitosis. Furthermore, both compounds triggered mitotic catastrophe followed by cell apoptosis via activation of PARP and Caspase 3, as well as downregulation of Mcl-1 anti-apoptotic protein in both CCA cell lines. In conclusion, pharmacologic PLK1 inhibition by BI6727 and GSK461364A blocked survival of CCA cells by several mechanisms. Our study provides evidence that BI6727 and GSK461364A could be alternative drugs and have potential implications at the clinical level for CCA therapy.

Multiple actions of NMS-P715, the monopolar spindle 1 (MPS1) mitotic checkpoint inhibitor in liver fluke-associated cholangiocarcinoma cells.

AIM: NMS-P715 is a potent inhibitor of monopolar spindle 1 (MPS1) mitotic checkpoint kinase. Overexpression of MPS1 is associated with short survival times in patients with cholangiocarcinoma (CCA). This study investigated the anti-cancer effects of NMS-P715 in human CCA cell lines. MAIN METHODS: KKU-100 and KKU-213A CCA cell lines were treated with NMS-P715 and cell viability was determined using MTT and colony formation assays. Inhibitory effects of NMS-P715 on cell cycle and apoptosis were evaluated using flow cytometry. Expression of underlying mechanism-related proteins was examined by Western blotting. Mitotic catastrophe was assessed by counting abnormal nuclei. Transwell assays were used to examine cell migration and invasion. KEY FINDINGS: Molecular docking showed that the NMS-P715/MPS1 complex was driven by an induced-fit mechanism. We provide new evidence that NMS-P715 potently inhibited cell proliferation and colony formation in both CCA cell lines. This was accompanied by induction of G2/M arrest and the consequent induction of mitotic catastrophe, a process that occurs during defective mitosis. The recent study showed that NMS-P715 activated caspase-dependent apoptosis and autophagosome formation with an increase of LC3 A/B-II protein expression in CCA cell lines. NMS-P715 also greatly impeded cell migration and invasion in CCA cell lines. The combination of NMS-P715 and gemcitabine or cisplatin showed synergistic effects on CCA cell proliferation. SIGNIFICANCE: This study revealed for the first time that NMS-P715 is a promising candidate for combating CCA owing via multiple actions and may be suitable for further development in a clinical study.

Reversine, a selective MPS1 inhibitor, induced autophagic cell death via diminished glucose uptake and ATP production in cholangiocarcinoma cells.

Reversine is a selective inhibitor of mitotic kinase monopolar spindle 1 (MPS1) and has been reported as an anticancer agent in various cancers. The effects of reversine on bile duct cancer, cholangiocarcinoma (CCA), a lethal cancer in Northeastern Thailand, were investigated. This study reports that reversine inhibited cell proliferation of CCA cell lines in dose- and time-dependent manners but had less inhibitory effect on an immortalized cholangiocyte cell line. Reversine also triggered apoptotic cell death by decreasing anti-apoptotic proteins, Bcl-XL and Mcl-1, increasing Bax pro-apoptotic protein and activating caspase-3 activity. Moreover, reversine induced autophagic cell death by increasing LC3-II and Beclin 1 while decreasing p62. Reversine activated autophagy via the AKT signaling pathway. Additionally, this study demonstrated for the first time that reversine could diminish the expression of Hypoxia-Inducible Factor 1- alpha (HIF-1α) and glucose transporter 1 (GLUT1), resulting in a reduction of glucose uptake and energy production in CCA cell lines. These findings suggest that reversine could be a good candidate as an alternative or supplementary drug for CCA treatment.

High Monopolar Spindle 1 Is Associated with Short Survival of Cholangiocarcinoma Patients and Enhances the Progression Via AKT and STAT3 Signaling Pathways.

Cholangiocarcinoma (CCA) is a malignancy of the bile duct epithelium. The major problems of this cancer are late diagnosis and a high rate of metastasis. CCA patients in advanced stages have poor survival and cannot be cured with surgery. Therefore, targeting molecules involved in the metastatic process may be an effective CCA treatment. Monopolar spindle 1 (MPS1) is a kinase protein that controls the spindle assemble checkpoint in mitosis. It is overexpressed in proliferating cells and various cancers. The functional roles of MPS1 in CCA progression have not been investigated. The aims of this study were to examine the roles and molecular mechanisms of MPS1 in CCA progression. Immunohistochemistry results showed that MPS1 was up-regulated in carcinogenesis of CCA in a hamster model, and positive expression of MPS1 in human CCA tissues was correlated to short survival of CCA patients (n = 185). Small interfering RNA (siRNA)-induced knockdown of MPS1 expression reduced cell proliferation via G2/M arrest, colony formation, migration, and invasion. Moreover, MPS1 controlled epithelial to mesenchymal transition (EMT)-mediated migration via AKT and STAT3 signaling transductions. MPS1 was also involved in MMPs-dependent invasion of CCA cell lines. The current research highlights for the first time that MPS1 has an essential role in promoting the progression of CCA via AKT and STAT3 signaling pathways and could be an attractive target for metastatic CCA treatment.