Thymidylate synthase, dihydropyrimidine dehydrogenase and thymidine phosphorylase expression in colorectal cancer and normal mucosa in patients.
OBJECTIVE
To compare thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD) and thymidine phosphorylase (TP) gene polymorphism and expression in colorectal cancer (CRC), and normal mucosa in chemotherapy-naïve patients.


METHODS
TS, DPD and TP mRNA expression was analysed by real-time reverse-transcription polymerase chain reaction in primary CRC and adjacent normal tissues from 53 patients with glyceraldehyde-3-phosphate dehydrogenase as housekeeping gene. TS promoter (TSER and C/G SNP) and DPD IVS14+1G>A genotypes were determined by polymerase chain reaction and restriction fragment length polymorphism assays. Moreover, the correlation between TS, DPD and TP expression and cytotoxicity of 5-fluorouracil was evaluated in Colo 320, HT-29, CaCo-2 and SW620 human CRC cell lines.


RESULTS
TP and DPD mRNA expression was significantly different in tumour and normal tissue (7.51+/-13.50 vs. 1.10+/-0.57, P<0.05 and 0.60+/-0.63 vs. 1.17+/-0.55, P<0.0001, respectively), whereas no differences were observed in TS mRNA levels. High-grade, undifferentiated tumours (WHO grade 3) had significantly higher mRNA levels of TS with respect to moderately differentiated (WHO grade 2) carcinomas (0.38+/-0.37 vs. 0.00+/-0.44, respectively; P<0.05). Noteworthy, TS mRNA expression was significantly decreased (P<0.05) in homozygous TSER*3G/3G (-0.35+/-0.35) with respect to pooled homozygous TSER*2/2 and heterozygous TSER*2/3 genotypes (0.14+/-0.41). In-vitro results showed a higher sensitivity to 5-FU of cell lines with the lowest TS expression.


CONCLUSIONS
The present results demonstrated significant differences in DPD and TP gene expression between normal mucosa and tumour samples, while TSER*3G/3G and high-grade histology were associated with significant variation in TS gene expression in tumour samples.
Amatori
Federica
F
Division of Pharmacology and Chemotherapy, Department of Internal Medicine, University of Pisa, Pisa, Italy.
Di Paolo
Antonello
A
Del Tacca
Mario
M
Fontanini
Gabriella
G
Vannozzi
Francesca
F
Boldrini
Laura
L
Bocci
Guido
G
Lastella
Marianna
M
Danesi
Romano
R
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology; D018938:Caco-2 Cells; D000069287:Capecitabine; D002277:Carcinoma / Q000235:genetics / Q000378:metabolism*; D015179:Colorectal Neoplasms / Q000235:genetics / Q000378:metabolism*; D003841:Deoxycytidine / Q000031:analogs & derivatives / Q000494:pharmacology; D042943:Dihydrouracil Dehydrogenase (NADP) / Q000235:genetics / Q000378:metabolism*; D005260:Female; D005472:Fluorouracil / Q000031:analogs & derivatives / Q000494:pharmacology; D015870:Gene Expression; D019073:HT29 Cells; D006801:Humans; D020128:Inhibitory Concentration 50; D007413:Intestinal Mucosa / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D013939:Thymidine Phosphorylase / Q000235:genetics / Q000378:metabolism*; D013940:Thymidylate Synthase / Q000235:genetics / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D000964:Antimetabolites, Antineoplastic; D003841:Deoxycytidine; D000069287:Capecitabine; D042943:Dihydrouracil Dehydrogenase (NADP); D013940:Thymidylate Synthase; D013939:Thymidine Phosphorylase; D005472:Fluorouracil