dehydroxymethylepoxyquinomicin and Bile-Duct-Neoplasms

Topics: Antineoplastic Agents; Bile Duct Neoplasms; Cell Line, Tumor; Cell Proliferation; Cholangiocarcinoma; Diterpenes; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Humans; Models, Molecular; Molecular Structure; Structure-Activity Relationship

Cholangiocarcinoma (CCA) is a dismal cancer. At present, there is no effective chemotherapeutic regimen for CCA. This may be due to the marked resistance of CCA to chemotherapy drugs, for which a mechanism remains unknown. Nuclear factor-κB (NF-κB) is constitutively activated in a variety of cancer cells, including CCA. It has been shown to play roles in growth, metastasis, and chemoresistance of cancer. In the present study, we examined whether NF-κB is involved in the chemoresistance of CCA and whether dehydroxymethylepoxyquinomicin (DHMEQ), an effective NF-κB inhibitor, can overcome the drug resistance of CCA. Two CCA cell lines, KKU-M213 and KKU-M214, were treated with DHMEQ and/or chemotherapeutic drugs. Cell viability, apoptosis, and the expressions of the ATP-binding cassette (ABC) transporters were compared. The combination of chemotherapy drugs, 5-fluorouracil, cisplatin, and doxorubicin, with DHMEQ significantly enhanced the cytotoxicity of all chemotherapeutic drugs compared to DHMEQ or drug alone. Furthermore, the mRNA level of ABCB1, a multidrug-resistant protein, was significantly decreased in the 5-fluorouracil combined with DHMEQ-treated cells. These findings suggest that the inhibition of NF-κB by DHMEQ enhanced the chemoresponsiveness of CCA cells, possibly by reducing the expression of ABC transporter. Inhibition of NF-κB may be a potential chemodrug-sensitizing strategy for chemoresistant cancer such as CCA.

Topics: Antineoplastic Agents; Apoptosis; ATP-Binding Cassette Transporters; Benzamides; Bile Duct Neoplasms; Cell Line, Tumor; Cell Survival; Cholangiocarcinoma; Cisplatin; Cyclohexanones; Doxorubicin; Drug Resistance, Neoplasm; Drug Synergism; Fluorouracil; Gene Expression; Humans; NF-kappa B

Up-regulation and association of nuclear factor kappa B (NF-κB) with carcinogenesis and tumor progression has been reported in several malignancies. In the current study, expression of NF-κB in cholangiocarcinoma (CCA) patient tissues and its clinical significance were determined. The possibility of using NF-κB as the therapeutic target of CCA was demonstrated.. Expression of NF-κB in CCA patient tissues was determined using immunohistochemistry. Dehydroxymethylepoxyquinomicin (DHMEQ), a specific NF-κB inhibitor, was used to inhibit NF-κB action. Cell growth was determined using an MTT assay, and cell apoptosis was shown by DNA fragmentation, flow cytometry and immunocytofluorescent staining. Effects of DHMEQ on growth and apoptosis were demonstrated in CCA cell lines and CCA-inoculated mice. DHMEQ-induced apoptosis in patient tissues using a histoculture drug response assay was quantified by TUNEL assay.. Normal bile duct epithelia rarely expressed NF-κB (subunits p50, p52 and p65), whereas all CCA patient tissues (n  =  48) over-expressed all NF-κB subunits. Inhibiting NF-κB action by DHMEQ significantly inhibited growth of human CCA cell lines in a dose- and time-dependent manner. DHMEQ increased cell apoptosis by decreasing the anti-apoptotic protein expressions-Bcl-2, XIAP-and activating caspase pathway. DHMEQ effectively reduced tumor size in CCA-inoculated mice and induced cell apoptosis in primary histocultures of CCA patient tissues.. NF-κB was over-expressed in CCA tissues. Inhibition of NF-κB action significantly reduced cell growth and enhanced cell apoptosis. This study highlights NF-κB as a molecular target for CCA therapy.

Topics: Animals; Apoptosis; Benzamides; Bile Duct Neoplasms; Bile Ducts, Intrahepatic; Blotting, Western; Cholangiocarcinoma; Cyclohexanones; Dose-Response Relationship, Drug; Female; Host-Parasite Interactions; Humans; Immunohistochemistry; Janus Kinase 3; Liver; Male; Mice, Inbred NOD; Mice, Knockout; Mice, SCID; Middle Aged; NF-kappa B; Opisthorchiasis; Opisthorchis; Tumor Burden; Xenograft Model Antitumor Assays