Correlation of thymidylate synthase, thymidine phosphorylase and dihydropyrimidine dehydrogenase with sensitivity of gastrointestinal cancer cells to 5-fluorouracil and 5-fluoro-2’-deoxyuridine

Table 2 Sensitivity to 5-FU or FdUrd and enzyme levels for cell lines

Cell line	IC50a		TS mRNAb	DPD		TP		Doubling time (hours)
	5-FU	FdUrd		mRNAb	proteinc	mRNAb	proteinc
MKN45	12.26 ± 2.13	16.85 ± 2.28	1.13 ± 0.22	0.57 ± 0.17	10.13	0.72 ± 0.13	5.11	22.9
SGC7901	8.97 ± 1.55	12.45 ± 1.46	1.04 ± 0.17	0.50 ± 0.09	9.13	0.59 ± 0.06	1.78	25.8
MKN28	3.44 ± 0.36	5.02 ± 1.32	0.84 ± 0.21	0.36 ± 0.12	4.57	0.70 ± 0.12	0.55	20.5
AGS	2.77 ± 0.58	19.31 ± 1.85	1.27 ± 0.23	0.35 ± 0.08	4.95	0.67 ± 0.20	3.835	29.5
SW1116	5.45 ± 0.47	24.21 ± 3.26	2.69 ± 0.36	0.47 ± 0.11	5.99	0.57 ± 0.11	2.60	22.2
Lovo	4.86 ± 0.92	14.41 ± 0.96	1.19 ± 0.12	0.31 ± 0.05	1.83	0.70 ± 0.08	0.04	33.9
HCT-8	1.28 ± 0.43	17.62 ± 1.84	1.54 ± 0.31	NDd	1.16	0.10 ± 0.06	0.67	28.1

a: values of IC50 (^-x±s), b: TS/DPD/TP mRNA levels, expressed as TS/DPD/TP:GAPDH product intensity ratio (^-x±s), c: DPD/TP protein levels, in U/mg protein, d: not detectable.