title: Increased activation of PI3K/AKT signaling pathway is associated with cholangiocarcinoma metastasis and PI3K/mTOR inhibition presents a possible therapeutic strategy.
abstract: Phosphatidylinositol 3-kinase (PI3K) signaling plays a critical role in cholangiocarcinoma (CCA), as well as anti-cancer drug resistance and autophagy, the type II program cell death regulation. In this work, we aimed to: (1) determine the expression levels of several key components of PI3K signaling and (2) evaluate whether NVP-BEZ235, a novel dual PI3K/mTOR inhibitor, could inhibit CCA cell growth. Immunohistochemistry for p85α, p110α, AKT, p-AKT (T308), mTOR, p-mTOR (S2448), GSK-3β, p-GSK-3β (S9), PTEN, and p-PTEN (S380, T382/383) was performed in 30 CCA patients. Western blotting was used to analyze PTEN and p-PTEN expression in the cell lines (KKU-OCA17, KKU-100, KKU-M055, KKU-M139, KKU-M156, KKU-M213, and KKU-M214). The effects of NVP-BEZ235 on CCA cells were evaluated using a growth inhibition assay, flow cytometer and migration assay. Increased activation of PI3K/AKT signaling was reproducibly observed in the CCA tissues. The expression of p85α, mTOR, and GSK-3β was significantly correlated with metastasis. Interestingly, PTEN suppression by loss of expression or inactivation by phosphorylation was observed in the majority of patients. Furthermore, NVP-BEZ235 effectively inhibited CCA cell growth and migration through reduced AKT and mTOR phosphorylation and significantly induced G1 arrest without apoptosis induction, although increase autophagy response was observed. In conclusion, the constitutive activation of PI3K/AKT pathway in CCA is mainly due to PTEN inactivation by either loss of expression or phosphorylation along with an increased expression in its pathway components heralding a poor prognosis for CCA patients. This work also indicates that inhibition of PI3K and mTOR activity by the inhibitor NVP-BEZ235 has anti-cancer activity against CCA cells which might be further tested for CCA treatment.
authors.affiliation: Department of Biochemistry and Liver Fluke and Cholangiocarcinoma Research Center, Faculty of Medicine, Khon Kaen University, Khon Kaen, 40002, Thailand.
authors.forename: Supak
authors.initials: S
authors.lastname: Yothaisong
authors.forename: Hasaya
authors.initials: H
authors.lastname: Dokduang
authors.forename: Anchalee
authors.initials: A
authors.lastname: Techasen
authors.forename: Nisana
authors.initials: N
authors.lastname: Namwat
authors.forename: Puangrat
authors.initials: P
authors.lastname: Yongvanit
authors.forename: Vajarabhongsa
authors.initials: V
authors.lastname: Bhudhisawasdi
authors.forename: Anucha
authors.initials: A
authors.lastname: Puapairoj
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Riggins
authors.forename: Watcharin
authors.initials: W
authors.lastname: Loilome
mesh_terms: D000328:Adult; D000368:Aged; D001650:Bile Duct Neoplasms / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D001653:Bile Ducts, Intrahepatic; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D018281:Cholangiocarcinoma / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D005260:Female; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism; D000071679:Glycogen Synthase Kinase 3 beta; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D051059:PTEN Phosphohydrolase / Q000378:metabolism; D058539:Phosphatidylinositol 3-Kinase / Q000378:metabolism*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010766:Phosphorylation / Q000187:drug effects; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D011804:Quinolines / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D058570:TOR Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D007093:Imidazoles; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011804:Quinolines; C546842:MTOR protein, human; D058539:Phosphatidylinositol 3-Kinase; C000605506:GSK3B protein, human; D000071679:Glycogen Synthase Kinase 3 beta; D051057:Proto-Oncogene Proteins c-akt; D058570:TOR Serine-Threonine Kinases; D038362:Glycogen Synthase Kinase 3; D051059:PTEN Phosphohydrolase; C531198:dactolisib