acetyl-aspartyl-glutamyl-valyl-aspartal and Cholangiocarcinoma

Constitutive activation of signal transducer and activator of transcription 3 (STAT3) signaling contributes to apoptosis resistance in cholangiocarcinoma. The aim of this study is to check whether matrine, an alkaloid isolated from traditional Chinese herb Sophora flavescens ait, can exert cytotoxic effects against cholangiocarcinoma cells via inactivation of STAT3 signaling.. Mz-ChA-1 and KMCH-1 cholangiocarcinoma cells were treated with matrine at 0.25-2.0 g/L for 48 h and cell viability and apoptosis were assessed. Apoptosis-related molecular changes and STAT3 phosphorylation and transcriptional activities were measured after matrine treatment for 48 h. The effect of expression of a constitutively active STAT3 mutant on matrine-induced apoptosis was determined.. Matrine significantly inhibited the viability and induced apoptosis in cholangiocarcinoma cells. Matrine treatment caused loss of mitochondrial membrane potential, release of mitochondrial cytochrome c, and activation of caspase-9 and -3. Matrine-induced apoptosis was inhibited in the presence of the caspase-3 inhibitor Ac-DEVD-CHO. Matrine reduced the phosphorylation levels of Janus kinase 2 (JAK2) and STAT3, inhibited STAT3-dependent transcriptional activity, and downregulated STAT3 target gene Mcl-1. Notably, expression of the constitutively active form of STAT3 significantly antagonized matrine-induced apoptosis of cholangiocarcinoma cells.. Matrine can trigger mitochondrial apoptotic death of cholangiocarcinoma cells largely through inhibition of JAK2/STAT3 signaling. Therefore, matrine represents a potentially effective anticancer agent for cholangiocarcinoma.

Topics: Alkaloids; Antineoplastic Agents; Apoptosis; Caspase 3; Caspase 9; Cell Line, Tumor; Cell Proliferation; Cholangiocarcinoma; Cytochromes c; Dose-Response Relationship, Drug; Drugs, Chinese Herbal; Humans; Janus Kinase 2; Matrines; Membrane Potential, Mitochondrial; Mutation; Myeloid Cell Leukemia Sequence 1 Protein; Oligopeptides; Quinolizines; Signal Transduction; STAT3 Transcription Factor

Cholangiocarcinoma (CCA), a tumour of the bile duct epithelium, occurs with a higher incidence in South-east Asian countries than in Europe and North America. The prognosis is poor, due to the unavailability of early diagnosis and the tumours being relatively resistant to chemotherapy. In the present study one of the fatal routes of this tumour was studied. This death was stimulated by TNF-alpha. TNF-alpha at a concentration of 760 pg/ml and 100 pg/ml in the presence of 1 microgram/ml actinomycin D induced 50% cell death of the two established human cholangiocarcinoma cell lines HuCCA-1 and HuCCA-INu, respectively. Preincubation of both cell lines with MoAb to TNF-RI or TNF-RII before TNF-alpha treatment showed that only the MoAb specific to TNF-RI inhibited death. The death of these two cell lines was proved to be apoptosis. Western blot analysis of extracts from both cell lines demonstrated a cleavage of poly (ADP-ribose) polymerase (PARP) within 6-8 h following TNF-alpha treatment. The degradation of PARP was prevented by a MoAb to TNF-RI indicating that the TNF-RI but not TNF-RII was involved in TNF-induced apoptosis in these two human cholangiocarcinoma cell lines. Moreover, peptide inhibitor for caspase II subfamily, Ac-DEVD-CHO, reduced the cytolysis of TNF-alpha-treated cholangiocarcinoma cells. The inhibitor also prevented degradation of PARP. These results indicate that the interaction between TNF-alpha and TNF-RI alone generated a sufficient signal to activate a caspase II subfamily-dependent apoptosis in human cholangiocarcinoma cell lines.

Topics: Antigens, CD; Apoptosis; Caspase Inhibitors; Caspases; Cholangiocarcinoma; DNA Fragmentation; Dose-Response Relationship, Drug; Humans; Oligopeptides; Poly(ADP-ribose) Polymerases; Protein Binding; Receptors, Tumor Necrosis Factor; Receptors, Tumor Necrosis Factor, Type I; Signal Transduction; Tumor Cells, Cultured; Tumor Necrosis Factor-alpha