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.     

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。     

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.     

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。     

Exercising with blocked muscle glycogenolysis: Adaptation in the McArdle mouse

Background

McArdle disease (glycogen storage disease type V) is an inborn error of skeletal muscle metabolism, which affects glycogen phosphorylase (myophosphorylase) activity leading to an inability to break down glycogen. Patients with McArdle disease are exercise intolerant, as muscle glycogen-derived glucose is unavailable during exercise. Metabolic adaptation to blocked muscle glycogenolysis occurs at rest in the McArdle mouse model, but only in highly glycolytic muscle. However, it is unknown what compensatory metabolic adaptations occur during exercise in McArdle disease.

血清胸苷激酶1测定在体检人群癌变风险筛查中的意义

目的探讨血清胸苷激酶1（STK1）检测在体检人群癌变风险筛查中的应用价值。方法应用酶免疫点印迹化学发光法检测2 230例健康体检者STK1浓度,根据检测结果把体检者分为风险组（STK1〉2pmol/L）和正常组（STK1≤2pmol/L）,计算风险率,风险组和正常组比较采用两独立样本资料的t检验,分别对风险组和正常组人群结合其他检查结果和临床症状对其进行分析。结果风险组79例,STK1为2.03~17.25pmol/L,平均值（3.77±2.99）pmol/L,风险率为3.5%,其中恶性肿瘤5例,发生率为6.33%,良性疾病74例,占93.67%;正常组2 151例,STK1为0.10~2.00pmol/L,平均值（0.91±0.32）pmol/L,无恶性肿瘤病例;风险组和正常组之间STK1水平比较,差异有统计学意义（t=8.490,P〈0.01）;在风险组中,恶性肿瘤组的STK1水平明显高于良性疾病组（t=9.142,P〈0.01）。结论 STK1的水平与体内细胞增殖有良好的相关性,在恶性肿瘤的早期发现中有一定的应用价值,可作为一种新的肿瘤标志物应用于体检人群的癌变风险筛查。     

Combined suicide and cytokine gene therapy for peritoneal carcinomatosis

BACKGROUND: Gene therapy is a novel approach for the treatment of cancers, and tumours disseminated in the peritoneal cavity are suitable for in situ delivery of a therapeutic gene. AIMS: The efficacy of a therapy combining a suicide gene (herpes simplex virus type I thymidine kinase (HSV-TK)) and cytokine genes was investigated in a model of peritoneal carcinomatosis induced by colon carcinoma cells in syngeneic rats. MATERIAL AND METHODS: Pre-established macroscopic tumours in BDIX rats were treated by intraperitoneal injections of retrovirus producing cells (FLYA13 TK, FLYA13 granulocyte macrophage-colony stimulating factor (GM-CSF), FLYA13 interleukin 12 (IL-12)) and ganciclovir (GCV). RESULTS: TK/GCV treated animals showed a slight increase in survival time (72 days) compared with the control group (63 days) while the association of cytokine and TK/GCV gene therapy resulted in significantly improved survival, with a large proportion of animals remaining tumour free on day 480 (60% and 40% for TK/GCV/GM-CSF and TK/GCV/IL-12 treated animals, respectively). Histological analysis of treated animals showed that the remaining tumour nodes were infiltrated by mononuclear cells but no major differences were observed between the various treatments. Immunohistochemical analysis revealed that lymphoid CD4(+) and CD8(+) T cells as well as macrophages accumulated outside untreated tumour nodes while CD8(+) and CD25(+) activated T cells and macrophages heavily infiltrated the tumours after the different treatments. CONCLUSIONS: Our data indicate that combined suicide and cytokine gene therapy is a powerful approach for the treatment of macroscopic peritoneal carcinomatosis.     

Crystal structure of Schistosoma purine nucleoside phosphorylase complexed with a novel monocyclic inhibitor

A novel inhibitor of Schistosoma PNP was identified using an “in silico” approach allied to enzyme inhibition assays. The compound has a monocyclic structure which has not been previously described for PNP inhibitors. The crystallographic structure of the complex was determined and used to elucidate the binding mode within the active site. Furthermore, the predicted pose was very similar to that determined crystallographically, validating the methodology. The compound Sm_VS1, despite its low molecular weight, possesses an IC₅₀ of 1.3 μM, surprisingly low when compared with purine analogues. This is presumably due to the formation of eight hydrogen bonds with key residues in the active site E203, N245 and T244. The results of this study highlight the importance of the use of multiple conformations for the target during virtual screening. Indeed the Sm_VS1 compound was only identified after flipping the N245 side chain. It is expected that the structure will be of use in the development of new highly active non-purine based compounds against the Schistosoma enzyme.