中国与北欧乳癌组织TP、TS、DPD mRNA表达比较

目的:检测北欧和中国人乳癌患者TP、TS、DPD mRNA水平的差异。方法:应用定量RT-PCR法检测北欧乳癌患者中3种指标的表达,用半定量RT-PCR法检测中国乳癌患者中3种指标的表达。结果:仅中国标本TP mRNA水平显示肿瘤组织(0.44±0.23)高于正常组织(0.15±0.16),TP mRNA高表达率中国患者(56.67%)高于北欧患者(34.12%),60岁以下患者这种差异消失。TS、DPD mRNA高表达率在二地区无差异。结论:北欧和中国乳癌患者之间TP、TS、DPD mRNA表达无明显种族差异。     

甲硫腺苷磷酸化酶基因在非小细胞肺癌中的转录表达及临床意义

目的 探讨甲硫腺苷磷酸化酶(MTAP)基因在非小细胞肺癌中的转录表达变化情况及其临床意义。方法 采用逆转录聚合酶链反应(RT-PCR)方法检测了15例新鲜肺癌标本及相应癌旁组织中MTAP mRNA的表达情况。同时运用Western印迹法检测了MTAP蛋白质的表达情况。结果 MTAP在73．30%,(11／15)的肿瘤标本中不表达或转录水平降低,而MTAP在癌旁对照组织中的表达率却高达93．3％(14／15);对于11例RT-PCR分析认定低表达或不表达的样本,再通过Western印迹方法进一步验证,发现与RT-PCR结果一致。另外,MTAP在肺腺癌和鳞癌中低表达现象差异无显著意义,但在中／低分化肺癌中的低表达与高分化癌相比增高,差异有显著意义。结论 MTAP基因低表达或丢失可能与肺癌的恶性程度密切相关。     

Thymidine phosphorylase expression is preserved after radiotherapy in patients with cervical squamous cell carcinoma

Purpose The aim of this study was to investigate the changes in two of the enzymes involved in fluorouracil metabolism, thymidine phosphorylase (TP) and dihydropyrimidine dehydrogenase (DPD), in uterine cervical squamous cell cancer tissue after radiotherapy.Subjects and methods Cervical tissue from 27 patients diagnosed with stage IIIB or IV uterine cervical squamous cell cancer was compared with normal cervical tissue from 33 patients with benign gynecologic diseases. Expression of TP and DPD in the cervical tissues was measured using enzyme-linked immunosorbent assays. TP and DPD expression before and after irradiation with 10 and 20 Gy was measured in 9 of the 27 patients with cervical cancer.Results Before irradiation, DPD expression in cancer tissue did not differ from that in normal tissue. TP expression and the TP/DPD ratio were significantly higher in cancer tissue than in normal tissue (P<0.00001). TP and DPD expression and the TP/DPD ratio were not significantly changed by irradiation with 10 and 20 Gy. TP expression and the TP/DPD ratio after irradiation with 10 and 20 Gy were significantly higher than in normal tissue.Conclusion The increased TP expression and the elevated TP/DPD ratio following irradiation with up to 20 Gy may offer an increased clinical advantage to chemoradiotherapy with capecitabine or doxyfluridine over radiotherapy alone.     

Mode of action of neuropeptides from the adipokinetic hormone family

Neuropeptides of the adipokinetic hormone (AKH) family regulate inter alia mobilisation of various substrates from stores in the fat body of insects during episodes of flight. How is this achieved? In insects which exclusively oxidise carbohydrates for flight (cockroaches), or which oxidise carbohydrates in conjunction with lipids (locusts) or proline (a number of beetles), the endogenous AKHs bind to a G(q)-protein-coupled receptor, activate a phospholipase C and the resulting inositol trisphosphate releases Ca(2+) from internal stores. In addition, influx of extracellular Ca(2+) is increased and, via a kinase cascade, glycogen phosphorylase is activated, glucose-1-phosphate produced, and transformed to trehalose, which is released into the haemolymph. In locusts, additionally, adenylate cyclase is activated and cyclic AMP is synthesised. In insects which use lipids for sustained flight (locust, tobacco hornworm moth) or proline for flight (certain beetles), adenylate cyclase is activated after the AKHs bind to their respective G(s)-protein-coupled receptor. The resulting cyclic AMP, together with the messengers intra- and extracellular Ca(2+), activate a triacylglycerol lipase, which results in the production of 1,2 diacylglycerols (in locusts, moths) or (hypothetically) free fatty acids (fruit beetle).     

Augmentation of the antitumor activity of capecitabine by a tumor selective dihydropyrimidine dehydrogenase inhibitor,RO0094889

Capecitabine is an orally available fluoropyrimidine and is finally converted to 5-FU selectively in tumor tissues. In our study, we examined whether the antitumor activity of capecitabine is directly affected by a modulation of dihydropyrimidine dehydrogenase (DPD). The modulations were carried out by the overexpression of DPD in tumor cells and by tumor selective DPD inhibition. The DPD-overexpressing cells were obtained by transfection of human DPD cDNA into HCT116 human colorectal cancer cells. The HCT116 cells bearing DPD cDNA expressed about 13 times higher DPD activities than the parental HCT116 cells, and they became significantly less susceptible to capecitabine than the parental cells when transplanted into nude mice. Administration of RO0094889 that is converted to a DPD inhibitor 5-vinyluracil selectively in tumor tissues restored the antitumor activity of capecitabine against the tumor of the HCT116 cells carrying DPD cDNA and various tumors expressing DPD. As compared to 5-ethynyluracil or 5-vinyluracil, which inhibited DPD not only in tumor tissues but also in other non-cancerous tissues, the effective dose range of RO0094889 in augmenting the efficacy of capecitabine was much broader. These results indicate that the antitumor activity of capecitabine is directly affected by DPD activities in tumor tissues and therefore, the combination of capecitabine and a tumor selective DPD inhibitor, RO0094889, will be beneficial to patients who have tumors with high levels of DPD.     

Biomodulation of 5-fluorouracil by interferon-α in human renal carcinoma cells: relationship to the expression of thymidine phosphorylase

Purpose: To provide the basis for improved therapeutic benefit in combination chemotherapy with interferon (IFN) and 5-fluorouracil (5-FU), we investigated the modulatory actions of human recombinant IFN alfa-2a on 5-FU in five renal cell carcinoma (RCC) cell lines in vitro, in particular focusing on thymidine phosphorylase (TP) expression. Methods: The sensitivity of RCC cell lines to the drugs was evaluated using an AlamarBlue assay. An enzyme-linked immunosorbent assay (ELISA) was used to determine TP expression. Results: IFN-α enhanced the sensitivity of three of five RCC cell lines to 5-FU in a dose- and schedule-dependent manner. When IFN-α was given prior to 5-FU, sensitivity to 5-FU was significantly higher than when IFN-α was given simultaneously (P < 0.05). IFN-α enhanced TP expression in a dose-dependent manner in three of five RCC cell lines (P < 0.05). The relative IFN-α-induced increase in sensitivity to 5-FU correlated with the relative IFN-α-induced increase in TP expression (P < 0.05). In addition, two of three RCC cell lines with more than a twofold increase in sensitivity to 5-FU induced by IFN-α showed a higher TP expression without IFN-α stimulation. Conclusions: These results suggest that IFN-α upregulates TP expression and modulates 5-FU anabolism thus enhancing 5-FU cytotoxicity in a dose- and schedule-dependent manner in some RCC cells. The results imply that TP expression measurement in RCC could identify subgroups of metastatic RCC that may respond to IFN-α/5-FU combination therapy, and sequential administration of IFN-α followed by 5-FU may be beneficial in such cases. Received: 18 August 1998 / Accepted: 28 October 1998     

Intratumoral pyrimidine nucleoside phosphorylase (pynpase) activity predicts a selective effect of adjuvant 5’-deoxy-5-fluorouridine (5’ dfur) on breast cancer

BACKGROUND: Pyrimidine nucleoside phosphorylase (PyNPase) is the enzyme that converts 5'-deoxy-5-fluorouracil (5'DFUR) to 5-fluorouracil (5FU). Its activity in cancer tissue may correlate with the selective antitumor activity of 5'DFUR in breast cancer. METHODS: Two hundred and sixteen T2 breast cancer patients were treated consecutively with surgery followed by 5'DFUR (600 mg/body/day) + tamoxifen (20 mg/body/day) for 2 years. PyNPase activity in breast cancer tissue, determined by high-performance liquid chromatography, ranged from 4.2-626.0 micrograms FU/mg protein/hr (mean +/- SD, 203.5 +/- 122.4), and the examined patients were divided into two groups: group A (high PyNPase group), cases with the PyNPase activity equal to or more than the mean value of 203.5 micrograms FU/mg protein/hr, and group B (low PyNPase group), cases with activity less than the mean value. RESULTS: Although there was no difference in relapse-free survival (RFS) between groups A and B, among node-positive patients (n = 83) those in group A tended to have a longer RFS. When divided into subgroups according to estrogen receptor (ER) status, among node-positive and ER-positive tumors (n = 49), the RFS was significantly better in group A than in group B (p < 0.05). CONCLUSION: Intratumoral PyNPase activity might be of use as a predictor of the effect of adjuvant 5'DFUR on breast cancer.     

转染胸苷磷酸化酶基因对5'-脱氧氟脲苷抗结肠癌细胞株活性的影响

目的 探讨人结肠癌细胞系SW480和LOVO细胞株转染胸苷磷酸化酶(TP)基因后转化5′-脱氧氟脲苷(5′-DFUR)为氟尿嘧啶(5-FU)能力的变化及5′-DFUR抗癌细胞株活性的变化.方法 构建包含TP cDNA的真核表达载体,用慢病毒包装后转染结肠癌细胞株SW480和LOVO.转染5代后以免疫荧光法和流式细胞技术检测转染效率;RT-PCR和Western blot法分别检测2株细胞的TP mRNA和TP蛋白表达.然后以高效液相色谱法(HPLC)检测2株细胞转染前后转化5′-DFUR为5-FU的量;MTT法检测5′-DFUR对2株细胞转染前后半数抑制浓度(IC50).结果 转染TP基因后SW480-TP与LOVO-TP 5代细胞转染效率稳定在95％左右.2株转染细胞的TP mRNA表达分别比野生型细胞增加(695±172)倍(t=-7.00,P=0.002)和(282±87)倍(t=-5.61,P=0.030),Western blot显示TP蛋白表达也明显增强.转染后的SW480-TP与LOVO-TP在培养基中分别使5′-DFUR转化为5-FU的量增加(t=19.406 ～66.921,P＜0.01).5′-DFUR对SW480的IC50由(1641±53) μmol/L降至(587±17) μmol/L(t=-32.59,P＜0.01);对LOVO的IC50由(1607±57) μmol/L降至(1088±89) μmol/L(t=-8.52,P＜0.01).结论 慢病毒载体能够高效地将TP cDNA转染至人结肠癌细胞SW480和LOVO并稳定传代,转染后2株细胞的TP mRNA和TP蛋白表达明显增高,使5′-DFUR转化为5-FU的量增加,对结肠癌细胞株SW480和LOVO的抑制作用增强.     

糖原磷酸化酶抑制剂高通量筛选模型的建立*

目的:建立糖原磷酸化酶(GPa)抑制剂的体外高通量筛选模型。方法:用梯度离心方法提取大鼠肝脏GPa,以葡萄糖-1-磷酸作为底物,通过测定反应中磷酸根的释放量,间接反映肝脏GPa的活性。通过对反应体系的优化,调整反应条件,建立96孔微孔板的高通量筛选模型,用咖啡因对此模型进行验证,并评价高通量技术参数[Z′-因子(Z-′factor),信号本底比(signal to background,S/B),信噪比(signal to noise,S/N)]。用此模型对5 000个样品(包括合成化合物、天然提取物)组成的随机库进行体外筛选,考察这些样品对GPa的抑制作用。结果:确定反应体系条件是:反应温度25℃,反应时间30 m in,底物浓度0.5 mmol.L-1,大鼠肝脏GPa的用量为250 ng。用此条件测定咖啡因对GPa的抑制曲线,计算其半数抑制浓度(IC50)为(285.3±39.6)μmol.L-1,与文献报道(IC50=240μmol.L-1)基本一致;本模型技术参数Z′-因子=0.79,S/B=0.45,S/N=11.32,表明此模型可以用于高通量筛选。应用此模型筛选得到有活性的化合物9个,其IC50在3.56~45.75μmol.L-1。结论:建立的体外GPa抑制剂高通量筛选模型具有快速、微量、准确的特点,可以作为研究降糖药的工具。     

TP/PD-ECGF表达与血小板增多在胃癌中的意义

目的：研究血小板衍化内皮细胞生长因子（TP/PD-ECGF）在胃癌中的表达及血小板增多情况,并对其与胃癌患者临床病理特征和预后的关系进行探讨。方法：采用免疫组化EnVision两步法检测107例胃癌组织中TP/PD-ECGF的表达,记录血小板增多情况,并分析二者与胃癌患者临床病理特征及预后的关系。结果：胃癌患者中TP/PD-ECGF阳性表达率为71.0%,与血小板增多呈正相关（P〈0.01）。TP/PD-ECGF表达、血小板增多与肿瘤分期、淋巴结转移、远处转移及分化程度呈正相关。TP/PD-ECGF阳性与阴性表达患者3年、5年总生存率分别为69.04%、18.12%和88.87%、75.20%,二者差异有统计学意义（P=0.0383）;3年、5年无进展生存率分别为64.87%、17.92%和82.73%、35.00%,二者差异有统计学意义（P=0.0350）。Cox比例风险模型多因素分析显示,肿瘤分期、淋巴结转移、远处转移、TP/PD-ECGF及血小板增多均是影响胃癌预后独立的危险因素。结论：TP/PD-ECGF表达与血小板增多呈正相关,二者与胃癌生长和浸润转移关系密切,可作为胃癌独立的预后因素。