thiourea and Cholangiocarcinoma

Cholangiocarcinoma (CCA) is a highly malignant and aggressive tumor of the bile duct that arises from epithelial cells. Chemotherapy is an important treatment strategy for CCA patients, but its efficacy remains limited due to drug resistance. Salubrinal, an inhibitor of eukaryotic translation initiation factor 2 alpha (eIF2α), has been reported to affect antitumor activities in cancer chemotherapy. In this study, the authors investigated the effect of salubrinal on the chemosensitivity of doxorubicin in CCA cells. They showed that doxorubicin induces CCA cell death in a dose- and time-dependent manner. Doxorubicin triggers reactive oxygen species (ROS) generation and induces DNA damage in CCA cells. In addition, ROS inhibitor N-acetylcysteine (NAC) pretreatment inhibits doxorubicin-induced CCA cell death. Importantly, these data demonstrate a synergistic death induction effect contributed by the combination of salubrinal and doxorubicin in CCA cells. It is notable that salubrinal promotes doxorubicin-induced ROS production and DNA damage in CCA cells. Taken together, these data suggest that salubrinal enhances the sensitivity of doxorubicin in CCA cells through promoting ROS-mediated DNA damage.

Topics: Antineoplastic Agents; Apoptosis; Bile Duct Neoplasms; Bile Ducts, Intrahepatic; Cell Line, Tumor; Cholangiocarcinoma; Cinnamates; DNA Damage; Doxorubicin; Drug Resistance, Neoplasm; Drug Synergism; Eukaryotic Initiation Factor-2; Humans; Reactive Oxygen Species; Thiourea

Less is known about the roles of eukaryotic initiation factor alpha (eIF2α) in cholangiocarcinoma (CCA). Here, we report that eIF2α inhibitor salubrinal inhibits the proliferation of human CCA cells. Clinical application of mammalian target of rapamycin (mTOR) inhibitors only has moderate antitumor efficacy. Therefore, combination approaches may be required for effective clinical use of mTOR inhibitors. Here, we investigated the efficacy of the combination of salubrinal and rapamycin in the treatment of CCA. Our data demonstrate a synergistic antitumor effect of the combination of salubrinal and rapamycin against CCA cells. Rapamycin significantly inhibits the proliferation of CCA cells. However, rapamycin initiates a negative feedback activation of Akt. Inhibition of Akt by salubrinal potentiates the efficacy of rapamycin both in vitro and in vivo. Additionally, rapamycin treatment results in the up-regulation of Bcl-xL in a xenograft mouse model. It is notable that salubrinal inhibits rapamycin-induced Bcl-xL up-regulation in vivo. Taken together, our data suggest that salubrinal and rapamycin combination might be a new and effective strategy for the treatment of CCA.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; bcl-X Protein; Bile Duct Neoplasms; Cell Line, Tumor; Cell Proliferation; Cholangiocarcinoma; Cinnamates; Drug Synergism; Eukaryotic Initiation Factor-2; Humans; Male; Mice, Nude; Phosphorylation; Proto-Oncogene Proteins c-akt; Signal Transduction; Sirolimus; Thiourea; Time Factors; TOR Serine-Threonine Kinases; Tumor Burden; Xenograft Model Antitumor Assays

Topics: Animals; Bile Duct Neoplasms; Bile Ducts, Intrahepatic; Cholangiocarcinoma; Epithelial-Mesenchymal Transition; Humans; Imidazoles; Receptors, G-Protein-Coupled; Thiourea

Cholangiocarcinoma (CCA) is a biliary cancer arising from damaged bile ducts. Epithelial-mesenchymal transition (EMT) occurs as epithelial cells begin to resemble mesenchymal cells leading to increased invasion potential as the extracellular matrix (ECM) degrades. Histamine exerts its effects by way of four receptors (H1-H4 HRs). Clobenpropit, a potent H4HR agonist, inhibits mammary adenocarcinoma growth. We have shown that (1) cholangiocytes and CCA cells express H1-H4 HRs and (2) the H3HR decreases CCA proliferation. We evaluated the effects of clobenpropit on CCA proliferation, invasion, EMT phenotypes, and ECM degradation. In vitro, we used CCA cell lines to study proliferation, signaling pathways, and the morphological invasive potential. Gene and protein expression of the hepatobiliary epithelial markers CK-7, CK-8, and CK-19, the focal contact protein paxillin, and the mesenchymal markers fibronectin, s100A4, and vimentin were evaluated. Cell invasion across an ECM layer was quantitated and matrix metalloproteinase-1, -2, -3, -9, and -11 gene and protein expression was examined. Evaluation of the specific role of H4HR was performed by genetic knockdown of the H3HR and overexpression of H4HR. Proliferation was evaluated by proliferating cellular nuclear antigen immunoblotting. In vivo, xenograft tumors were treated with either vehicle or clobenpropit for 39 days. Tumor volume was recorded every other day. Clobenpropit significantly decreased CCA proliferation by way of a Ca(2+) -dependent pathway and altered morphological development and invasion. Loss of H3HR expression or overexpression of H4HR significantly decreased CCA proliferation. In vivo, clobenpropit inhibited xenograft tumor growth compared with controls.. Modulation of H4HR by clobenpropit disrupts EMT processes, ECM breakdown, and invasion potential and decreases tumor growth. Interruption of tumorigenesis and invasion by histamine may add to therapeutic advances for CCAs.

Topics: Animals; Apoptosis; Bile Duct Neoplasms; Bile Ducts, Intrahepatic; Biopsy; Cell Division; Cell Line, Tumor; Cholangiocarcinoma; Cyclic AMP; Disease Progression; Epithelial-Mesenchymal Transition; Extracellular Matrix; Histamine H3 Antagonists; Humans; Imidazoles; Inositol 1,4,5-Trisphosphate; Mice; Receptors, G-Protein-Coupled; Receptors, Histamine; Receptors, Histamine H4; RNA, Small Interfering; Signal Transduction; Thiourea; Xenograft Model Antitumor Assays