title: PRKAR1A overexpression is associated with increased ECPKA autoantibody in liver fluke-associated cholangiocarcinoma: application for assessment of the risk group.
abstract: Cholangiocarcinoma (CCA) associated with Opisthorchis viverrini (Ov) chronic infection is the most frequent primary liver cancer in Thailand, and current approaches to early diagnosis and curative treatments are largely disappointing. We hypothesize a role for protein kinase A (PKA) in Ov-induced CCA. First, we studied the PKA isozyme switching in the liver from the hamster CCA model using quantitative (q) PCR, in situ hybridization, and immunohistochemical and western blot analysis. Second, the presence of extracellular PKA (ECPKA) in CCA cell lines and their conditioned media was demonstrated by western blot and PKA activity assay. Third, we determined the association between PRKAR1A expression and serum ECPKA autoantibody in patients with CCA by ELISA. We demonstrated that an increased PRKAR1A expression is restricted to the biliary cells starting from week 1, with remarkable up-regulation when CCA has completely developed by week 24. The switching of the PKA regulatory subunit isoforms from PRKAR2B/PKAII to PRKAR1A/PKAI is significantly associated with cholangiocyte proliferation. Further, we observed that human CCA cell lines express PRKAR1A but not PRKAR2B and excrete ECPKA. Finally, ECPKA autoantibodies are detected in serum of patients with CCA, adenocarcinoma, and Ov infection with periductal fibrosis, but not from Ov-infected subjects without periductal fibrosis lesion and healthy controls. We conclude that PKA isozyme switching and the PRKAR1A/PKAI pathway might contribute to the induction of cholangiocyte transformation and proliferation in Ov-induced CCA. Overexpression of PRKAR1A leads to secretion of ECPKA which is associated with serum autoantibody that may constitute a biomarker for human CCA genesis.
authors.affiliation: Department of Biochemistry and Liver Fluke and Cholangiocarcinoma Research Center, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand.
authors.forename: Watcharin
authors.initials: W
authors.lastname: Loilome
authors.forename: Sasithorn
authors.initials: S
authors.lastname: Yooyuen
authors.forename: Nisana
authors.initials: N
authors.lastname: Namwat
authors.forename: Paiboon
authors.initials: P
authors.lastname: Sithithaworn
authors.forename: Anucha
authors.initials: A
authors.lastname: Puapairoj
authors.forename: Junko
authors.initials: J
authors.lastname: Kano
authors.forename: Masayuki
authors.initials: M
authors.lastname: Noguchi
authors.forename: Masanao
authors.initials: M
authors.lastname: Miwa
authors.forename: Puangrat
authors.initials: P
authors.lastname: Yongvanit
mesh_terms: D000230:Adenocarcinoma / Q000276:immunology / Q000378:metabolism / Q000469:parasitology; D000818:Animals; D001323:Autoantibodies / Q000097:blood*; D001650:Bile Duct Neoplasms / Q000209:etiology / Q000378:metabolism* / Q000473:pathology; D001653:Bile Ducts, Intrahepatic / Q000378:metabolism* / Q000469:parasitology / Q000473:pathology; D015153:Blotting, Western; D016022:Case-Control Studies; D018281:Cholangiocarcinoma / Q000209:etiology / Q000378:metabolism* / Q000473:pathology; D006224:Cricetinae; D017077:Culture Media, Conditioned / Q000494:pharmacology; D054757:Cyclic AMP-Dependent Protein Kinase RIIbeta Subunit / Q000235:genetics / Q000378:metabolism; D054756:Cyclic AMP-Dependent Protein Kinase RIalpha Subunit / Q000235:genetics / Q000378:metabolism*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000276:immunology* / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005210:Fasciola hepatica / Q000472:pathogenicity; D005211:Fascioliasis / Q000276:immunology / Q000378:metabolism* / Q000469:parasitology; D005434:Flow Cytometry; D006801:Humans; D007124:Immunoenzyme Techniques; D008647:Mesocricetus; D009889:Opisthorchiasis / Q000276:immunology / Q000378:metabolism* / Q000469:parasitology; D009891:Opisthorchis / Q000472:pathogenicity; D011379:Prognosis; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012307:Risk Factors; D014407:Tumor Cells, Cultured
chemical_list: D001323:Autoantibodies; D017077:Culture Media, Conditioned; D054757:Cyclic AMP-Dependent Protein Kinase RIIbeta Subunit; D054756:Cyclic AMP-Dependent Protein Kinase RIalpha Subunit; C517834:PRKAR1A protein, human; C517837:PRKAR2B protein, human; D012333:RNA, Messenger; D017868:Cyclic AMP-Dependent Protein Kinases