Peters G J, Laurensse E, Leyva A, Lankelma J, Pinedo H M
Cancer Res. 1986 Jan;46(1):20-8.
Six cell lines differing in histological origin were studied regarding the growth inhibitory effect of fluoropyrimidines in relation to their metabolism. The human colon carcinoma cell line WiDr was most sensitive to 5-fluorouracil (FUra) (50% growth inhibitory concentration, 0.7 microM) and to its analogue 5'deoxy-5-fluorouridine (5'dFUR) (50% growth inhibitory concentration, 18 microM). The murine B16 melanoma cell line was moderately sensitive to FUra but least sensitive to 5'dFUR. The 50% growth inhibitory concentration values in the human melanoma cell lines IGR3 and M5, the transformed human intestine cell line intestine 407 and the rat hepatoma cell line H35 varied for FUra between 1.7 and 5.0 microM, and for 5'dFUR between 54 and 160 microM. Several enzymes from pyrimidine metabolism responsible for FUra metabolism were measured with FUra as a substrate. The activity of uridine phosphorylase, which catalyzes the conversion of 5'dFUR to FUra, was lowest in B16 cells correlating with the low sensitivity to 5'dFUR. When adenosine 5'-triphosphate was included in the reaction mixture for uridine phosphorylase, FUra was rapidly channeled into FUra nucleotides via its nucleoside. The rate of channeling appeared to correlate with the nucleoside phosphorylase activity in the various cell lines. In several cell lines activities of nucleotide-degrading enzymes were rather high and interfered with the measurement of orotate phosphoribosyl transferase (OPRT) with FUra as substrate. Addition of the phosphatase inhibitor glycerol-2-phosphate partly prevented breakdown of the newly formed 5-fluorouridine 5'-monophosphate and enabled measurement of OPRT. The WiDr cell line had a relatively high OPRT activity which could explain its sensitivity to FUra. The activity of thymidylate synthase was measured at a suboptimal concentration of 1 microM and at the optimal concentration of 10 microM deoxyuridine 5'-phosphate. With all cell lines the ratio between the activities at 10 and 1 microM was between 2.3 and 3.6. The activity of thymidylate synthase was lowest in WiDr and IGR3 cells and 3-4 times higher in M5 and Intestine 407 cells. The inhibition of 0.01 microM 5-fluorodeoxyuridine 5'-monophosphate was 80-90% at 1 microM deoxyuridine 5'-phosphate and 50-70% at 10 microM deoxyuridine 5'-phosphate with all cell lines. At 0.1 microM 5-fluorodeoxyuridine 5'-monophosphate enzyme activity was inhibited by 95-100%. The incorporation of FUra into RNA was relatively low in IGR3 cells and 3-5 times higher in all other cell lines.(ABSTRACT TRUNCATED AT 400 WORDS)
研究了六种组织学来源不同的细胞系对氟嘧啶生长抑制作用及其代谢的关系。人结肠癌细胞系WiDr对5-氟尿嘧啶（FUra）最敏感（50%生长抑制浓度，0.7微摩尔）及其类似物5'-脱氧-5-氟尿苷（5'dFUR）（50%生长抑制浓度，18微摩尔）。小鼠B16黑色素瘤细胞系对FUra中度敏感，但对5'dFUR最不敏感。人黑色素瘤细胞系IGR3和M5、转化的人肠细胞系肠407和大鼠肝癌细胞系H35中，FUra的50%生长抑制浓度值在1.7至5.0微摩尔之间，5'dFUR在54至160微摩尔之间。以FUra为底物测定了几种嘧啶代谢中负责FUra代谢的酶。催化5'dFUR转化为FUra的尿苷磷酸化酶活性在B16细胞中最低，这与对5'dFUR的低敏感性相关。当将三磷酸腺苷加入尿苷磷酸化酶的反应混合物中时，FUra通过其核苷迅速转化为FUra核苷酸。转化速率似乎与各种细胞系中的核苷磷酸化酶活性相关。在几个细胞系中，核苷酸降解酶的活性相当高，干扰了以FUra为底物的乳清酸磷酸核糖基转移酶（OPRT）的测定。加入磷酸酶抑制剂甘油-2-磷酸部分阻止了新形成的5-氟尿苷5'-单磷酸的分解，并能够测定OPRT。WiDr细胞系具有相对较高的OPRT活性，这可以解释其对FUra的敏感性。胸苷酸合成酶的活性在1微摩尔次优浓度和10微摩尔脱氧尿苷5'-磷酸的最佳浓度下测定。在所有细胞系中，10微摩尔和1微摩尔时的活性之比在2.3至3.6之间。胸苷酸合成酶的活性在WiDr和IGR3细胞中最低，在M5和肠407细胞中高3至4倍。在所有细胞系中，0.01微摩尔5-氟脱氧尿苷5'-单磷酸在1微摩尔脱氧尿苷5'-磷酸时的抑制率为80-90%，在10微摩尔脱氧尿苷5'-磷酸时为50-70%。在0.1微摩尔5-氟脱氧尿苷5'-单磷酸时，酶活性被抑制95-100%。IGR3细胞中FUra掺入RNA的量相对较低，在所有其他细胞系中高3至5倍。（摘要截断于400字）
