Orotate phosphoribosyl transferase mRNA expression and the response of cholangiocarcinoma to 5-fluorouracil.
OBJECTIVE
To determine whether expression of certain enzymes related to 5-fluorouracil (5-FU) metabolism predicts 5-FU chemosensitivity in cholangiocarcinoma (CCA).


METHODS
The histoculture drug response assay (HDRA) was performed using surgically resected CCA tissues. Tumor cell viability was determined morphologically with hematoxylin and eosin- and terminal deoxynucleotide transferase-mediated dUTP nick-end labeling-stained tissues. The mRNA expression of thymidine phosphorylase (TP), orotate phosphoribosyl transferase (OPRT), thymidylate synthase (TS), and dihydropyrimidine dehydrogenase (DPD) was determined with real-time reverse transcriptase-polymerase chain reaction. The levels of gene expression and the sensitivity to 5-FU were evaluated.


RESULTS
Twenty-three CCA tissues were obtained from patients who had been diagnosed with intrahepatic CCA and who underwent surgical resection at Srinagarind Hospital, Khon Kaen University from 2007 to 2009. HDRA was used to determine the response of these CCA tissues to 5-FU. Based on the dose-response curve, 200 μg/mL 5-FU was selected as the test concentration. The percentage of inhibition index at the median point was selected as the cut-off point to differentiate the responding and non-responding tumors to 5-FU. When the relationship between TP, OPRT, TS and DPD mRNA expression levels and the sensitivity of CCA tissues to 5-FU was examined, only OPRT mRNA expression was significantly correlated with the response to 5-FU. The mean expression level of OPRT was significantly higher in the responder group compared to the non-responder group (0.41 ± 0.25 vs 0.22 ± 0.12, P < 0.05).


CONCLUSIONS
OPRT mRNA expression may be a useful predictor of 5-FU chemosensitivity of CCA. Whether OPRT mRNA could be used to predict the success of 5-FU chemotherapy in CCA patients requires confirmation in patients.
Department of Microbiology, Center of Excellence for Innovation in Chemistry, and Liver Fluke and Cholangiocarcinoma Research Center, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand. hchari@kku.ac.th
Chariya
C
Hahnvajanawong
Jariya
J
Chaiyagool
Wunchana
W
Seubwai
Vajarabhongsa
V
Bhudhisawasdi
Nisana
N
Namwat
Narong
N
Khuntikeo
Banchob
B
Sripa
Ake
A
Pugkhem
Wichittra
W
Tassaneeyakul
D000328:Adult; D000368:Aged; D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology*; D001650:Bile Duct Neoplasms / Q000188:drug therapy / Q000201:enzymology* / Q000235:genetics; D001653:Bile Ducts, Intrahepatic; D002470:Cell Survival / Q000187:drug effects; D018281:Cholangiocarcinoma / Q000188:drug therapy / Q000201:enzymology* / Q000235:genetics; D042943:Dihydrouracil Dehydrogenase (NADP) / Q000235:genetics; D005260:Female; D005472:Fluorouracil / Q000494:pharmacology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009962:Orotate Phosphoribosyltransferase / Q000235:genetics*; D011237:Predictive Value of Tests; D012333:RNA, Messenger / Q000378:metabolism*; D013939:Thymidine Phosphorylase / Q000235:genetics; D013940:Thymidylate Synthase / Q000235:genetics; D014407:Tumor Cells, Cultured
D000964:Antimetabolites, Antineoplastic; D012333:RNA, Messenger; D042943:Dihydrouracil Dehydrogenase (NADP); D013940:Thymidylate Synthase; D009962:Orotate Phosphoribosyltransferase; D013939:Thymidine Phosphorylase; D005472:Fluorouracil