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。     

Activation of Phosphorylase by Anoxia and Dinitrophenol in Rabbit Colon Smooth Muscle: Relation to Release of Calcium from Mitochondria

Abstract: The effect of anoxia or 2,4-dinitrophenol (DNP) on the phosphorylase a activity and the calcium content in subcellular fractions from rabbit colon smooth muscle was studied. Anoxia for 15 min. as well as DNP (6.6 × 10^?5 M) for 5 min. increased the phosphorylase a activity. The calcium content in the mitochondrial subfraction, prepared from the anoxic- or DNP-treated intact muscle and determined by atomic absorption spectroscopy, was reduced. The calcium content in the nuclear and the microsomal fractions was not changed in preparations with a normal Ca-content. When the muscle was incubated for 60 min. in a Ca²⁺-free medium containing 2.0 mM EGTA, the calcium content in the mitochondrial fraction was reduced to 38 % of the control. This calcium level was still further reduced and the phosphorylase a activity was increased by DNP in this “Ca-poor” muscle. In these preparations the Ca-content of the microsomal + supernatant fraction increased. Only when the muscle was incubated, initially, in an anoxic medium containing 0.1 mM Ca²⁺ for 120 min. and, subsequently, in an oxygenated medium containing 0.1 mM Ca²⁺ for 20 min., DNP failed to activate phosphorylase and to decrease the calcium content in the mitochondrial fraction. These results indicate that mitochondrial Ca²⁺ release is one of the regulatory factors of the anoxic-induced glycogenolysis.     

Conversion of 2,6-diamino-9-(2-hydroxyethoxymethyl)purine to acyclovir as catalyzed by adenosine deaminase

Adenosine deaminase (ADA) was partially purified from several sources using affinity chromatography. These enzymes have the capacity to catalyze the deamination of 2,6-diamino-9-(2-hydroxyethoxymethyl)purine (A134U) to form the antiviral agent acyclovir [9-(2-hydroxyethoxymethyl)guanine]. Their relative substrate efficiencies (Vmax/Km) with A134U (standardized to adenosine = 100) were: dog ADA, 0.092; human ADA, 0.015-0.029; rat ADA, 0.025; calf ADA, 0.016; and Escherichia coli ADA, 0.0003. In addition to having the lowest efficiency with A134U, the bacterial ADA was also distinguished by its lack of binding of the mammalian ADA inhibitor erythro-9-(2-hydroxy-3-nonyl)adenine and by its weak binding to the 9-(p-aminobenzyl)adenine-agarose affinity column. Four minor metabolites of A134U and acyclovir have been reported to be produced in the rat. These compounds are oxidized on either the C-8 position of the ring or the terminal carbon of the side chain. Neither acyclovir nor any of these metabolites produced significant inhibition of calf intestine ADA. The oxidized metabolites containing an N-6 amino group were extremely slow substrates of this enzyme.     

Influence of alpha-tumor necrosis factor and beta-interleukin-1 on production of angiogenetic factors and thymidine phosphorylase activity in immortalized human decidual fibroblasts in vitro

AIM: The aim of the present study was to investigate regulatory mechanisms of angiogenesis in the decidua using immortalized human decidual fibroblasts. METHODS: A sample of decidual fibroblasts was taken from a woman in early pregnancy. A cell line, DE-1, was established by infecting the decidual fibroblasts with the simian virus 40 large T antigen. Using this cell line, the ability to produce vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), beta-transforming growth factor (TGF-beta), and thymidine phosphorylase (TP) activity was investigated using immunohistochemistry, and the influences of beta-interleukin-1 (IL-1beta) and alpha-tumor necrosis factor (TNF-alpha) on these angiogenetic factors was investigated using enzyme-linked immunosorbent assays. Furthermore, the effects of TNF-alpha on proliferative capacity and apoptosis induction in DE-1 were studied. RESULTS: It was demonstrated that DE-1 produced all of these angiogenetic factors. The production of VEGF, bFGF and TGF-beta respectively was enhanced by both IL-1beta and TNF-alpha. TP activity was increased by TNF-alpha, but no increase was observed as a result of IL-1beta. It was shown that TNF-alpha suppressed the proliferation of DE-1 cells and significantly increased the percentage of apoptotic cells. CONCLUSION: It is suggested that IL-1beta and TNF-alpha stimulate decidual fibroblasts to up-regulate angiogenesis in the human decidua.     

Molecular and traditional chemotherapy: A united front against prostate cancer

Castrate resistant prostate cancer (CRPC) is essentially incurable. Recently though, chemotherapy demonstrated a survival benefit (∼2 months) in the treatment of CRPC. While this was a landmark finding, suboptimal efficacy and systemic toxicities at the therapeutic doses warranted further development. Smart combination therapies, acting through multiple mechanisms to target the heterogeneous cell populations of PC and with potential for reduction in individual dosing, need to be developed. In that, targeted molecular chemotherapy has generated significant interest with the potential for localized treatment to generate systemic efficacy. This can be further enhanced through the use of oncolytic conditionally replicative adenoviruses (CRAds) to deliver molecular chemotherapy. The prospects of chemotherapy and molecular-chemotherapy as single and as components of combination therapies are discussed.     

Vorinostat synergises with capecitabine through upregulation of thymidine phosphorylase

Background:

Potentiation of anticancer activity of capecitabine is required to improve its therapeutic index. In colorectal cancer (CRC) cells, we evaluated whether the histone deacetylase-inhibitor vorinostat may induce synergistic antitumour effects in combination with capecitabine by modulating the expression of thymidine phosphorylase (TP), a key enzyme in the conversion of capecitabine to 5-florouracil (5-FU), and thymidylate synthase (TS), the target of 5-FU.

Methods:

Expression of TP and TS was measured by real-time PCR, western blotting and immunohistochemistry. Knockdown of TP was performed by specific small interfering RNA. Antitumour activity of vorinostat was assessed in vitro in combination with the capecitabine active metabolite deoxy-5-fluorouridine (5′-DFUR) according to the Chou and Talay method and by evaluating apoptosis as well as in xenografts-bearing nude mice in combination with capecitabine.

Results:

Vorinostat induced both in vitro and in vivo upregulation of TP as well as downregulation of TS in cancer cells, but not in ex vivo treated peripheral blood lymphocytes. Combined treatment with vorinostat and 5′-DFUR resulted in a synergistic antiproliferative effect and increased apoptotic cell death in vitro. This latter effect was impaired in cells where TP was knocked. In vivo, vorinostat plus capecitabine potently inhibited tumour growth, increased apoptosis and prolonged survival compared with control or single-agent treatments.

Conclusions:

Overall, this study suggests that the combination of vorinostat and capecitabine is an innovative antitumour strategy and warrants further clinical evaluation for the treatment of CRC.     

Fluoropyrimidine resistance in colon cancer

A significant obstacle for the management of patients with colorectal cancer is intrinsic drug resistance or in patients that respond to chemotherapy, acquired drug resistance. Drug resistance can occur through a variety of mechanisms. These include alterations in drug influx, drug efflux, intracellular metabolic activation, intracellular catabolism, through alterations in the drug’s target or through numerous changes downstream of the target including alterations in genes involved in the regulation of the cell cycle, apoptosis or in DNA damage repair. In this article, the mechanisms of action and the mechanisms of resistance to the fluoropyrimidines are reviewed focusing on newer studies using tumor samples obtained from patients. Clinical trials that can potentially overcome the relevant mechanisms of resistance are described.     

5-氟尿嘧啶代谢酶在胃癌中的表达及预后价值

目的:探讨二氢嘧啶脱氢酶(dihydropyrimidine dehydrogenase,DPD)、胸苷酸合成酶(thymidylate synthase,TS)和胸苷磷酸化酶(thymidine phosphorylase,TP)在胃癌中的表达及预后价值。方法:42例胃癌患者于根治术后分别施以5-氟尿嘧啶(5-FU)为主的辅助化疗,并通过免疫组织化学检测DPD、TS和TP的表达,比较上述代谢酶表达与临床病理因素和预后之间的关系。结果:胃癌组织中DPD在肠型中的表达率显著高于弥漫型(65%比25%,P=0.025),TS和TP倾向高表达于分期较晚的胃癌患者中(P0.05)。结论:在接受5-FU为主的辅助化疗胃癌患者中,DPD表达有可能成为重要的预后指标;而TS和TP表达则与肿瘤进展及临床分期密切相关。