Capecitabine-Based Chemoendocrine Combination as First-Line Treatment for Metastatic Hormone-Positive Metastatic Breast Cancer: Phase 2 Study

BackgroundPreclinical studies have suggested a synergistic effect of tamoxifen and capecitabine in estrogen receptor–positive cell lines. We evaluated the safety and efficacy of first-line chemoendocrine treatment in patients with metastatic breast cancer. Biochemical assessment was performed of serum levels of thymidine phosphorylase enzyme (TP), serum tamoxifen, hydroxytamoxifen, and 5-fluorouracil in relationship to efficacy.Patients and MethodsThis prospective phase 2 interventional study studied patients with estrogen receptor-positive, HER2⁻ metastatic breast cancer who received either tamoxifen/capecitabine or letrozole/capecitabine as first-line treatment. The dose of capecitabine provided at 2000 mg per day continuously as a fixed dose.ResultsForty women with a median age of 49.3 years were enrolled. For the whole study group, median progression-free survival (PFS) was 10 months and median overall survival (OS) was 23.3 months. The overall response rate was 60% and the clinical benefit rate 82.5%. Progesterone receptor positivity was associated with significantly longer PFS (12 vs. 7 months, P = .021). The most frequent adverse events were palmar–plantar erythrodysesthesia (62.5%), fatigue (62.5%), diarrhea (30%), abdominal pain (12.5%), and constipation (10%). Changes in serum level of TP were not correlated to response to treatment, PFS, or OS. Higher serum levels of tamoxifen and hydroxytamoxifen were correlated with higher response rates and longer PFS but not OS.ConclusionChemoendocrine treatment is well tolerated, with no evidence of contradictory effects between the combination components. However, the efficacy data need more validation.     

Tumour suppressors miR-1 and miR-133a target the oncogenic function of purine nucleoside phosphorylase (PNP) in prostate cancer

Background:

Our recent analyses of miRNA expression signatures showed that miR-1 and miR-133a were significantly reduced in several types of cancer. Interestingly, miR-1 and miR-133a are located on the same chromosomal locus in the human genome. We examined the functional significance of miR-1 and miR-133a in prostate cancer (PCa) cells and identified the novel molecular targets regulated by both miR-1 and miR-133a.

Methods and Results:

The expression levels of miR-1 and miR-133a were significantly downregulated in PCa compared with non-PCa tissues. Restoration of miR-1 or miR-133a in PC3 and DU145 cells revealed significant inhibition of proliferation, migration, and invasion. Molecular target identification by genome-wide gene expression analysis and luciferase reporter assay showed that purine nucleoside phosphorylase (PNP) was directly regulated by both miRNAs. Silencing of the PNP gene inhibited proliferation, migration, and invasion in both PC3 and DU145 cells. Immunohistochemistry detected positive staining of PNP in PCa specimens.

Conclusions:

Downregulation of miR-1 and miR-133a was a frequent event in PCa and both function as tumour suppressors. The PNP is a novel target gene of both miRNAs and potentially functions as an oncogene. Therefore, identification of novel molecular networks regulated by miRNAs may provide new insights into the underlying causes of PCa oncogenesis.     

Glutathione-dependent reduction of arsenate by glycogen phosphorylase responsiveness to endogenous and xenobiotic inhibitors.

Rabbit muscle glycogen phosphorylase-a (GPa) reduces arsenate (As(V)) to the more toxic arsenite (As(III)) in a glutathione (GSH)-dependent fashion. To determine whether reduction of As(V) by GPa is countered by compounds known to inhibit GP-catalyzed glycogenolysis, the effects of thiol reagents, endogenous compounds (glucose, ATP, ADP) as well as nonspecific glycogen phosphorylase inhibitors (GPIs; caffeine, quercetin, flavopiridol [FP]), and specific GPIs (1,4-dideoxy-1,4-imino-D-arabinitol [DAB], BAY U6751, CP320626) were tested on reduction of As(V) by rabbit muscle GPa in the presence of glycogen (substrate), AMP (activator), and GSH, and the As(III) formed from As(V) was quantified by high-performance liquid chromatography-hydride generation-atomic fluorescence spectrometry. The As(V)-reducing activity of GPa was moderately sensitive to thiol reagents. Glucose above 5mM and ADP or ATP at physiological levels diminished GPa-catalyzed As(V) reduction. All GPIs inhibited As(V) reduction by GPa in a concentration-dependent fashion; however, their effects were differentially affected by glucose (10mM) or AMP (200microM instead of 25microM), known modulators of the action of some GPIs on the GP-catalyzed glycogenolysis. Inhibition of As(V) reduction by DAB and quercetin was not influenced by glucose or AMP. Glucose that potentiates the inhibitory effects of caffeine, BAY U6751, and CP320626 on the glycogenolytic activity of GPa also enhanced the inhibitory effects of these GPIs on GPa-catalyzed As(V) reduction. AMP at high concentration alleviated the inhibition by BAY U6751 and CP320626 (whose antagonistic effect on GP-catalyzed glycogen breakdown is also AMP sensitive), whereas the inhibition in As(V) reduction by FP or caffeine was little affected by AMP. Thus, GPIs inhibit both the glycogenolytic and As(V)-reducing activities of GP, supporting that the latter is coupled to glycogenolysis. It was also shown that a GPa-rich extract of rat liver contained GSH-dependent As(V)-reducing activity that was inhibited by specific GPIs, suggesting that the liver-type GPa can also catalyze reduction of As(V).     

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。     

Histocytochemical and immunohistochemical studies related to the role of glycogen in human developing digestive organs

To elucidate the role of glycogen in the epithelium of developing digestive organs, we investigated the appearance of glycogen and glycogen phosphorylase (GP) in these organs. We studied 64 externally normal human embryos at Carnegie stages 13–23 (5.1–28.0 mm in crown-ramp length, 4–8 weeks of gestation) by histocytochemical staining for glycogen and immunohistochemical staining with antibodies against two isoenzymes of GP: brain-type (BGP) and mucle-brain-type (MBGP) GP. At stage 13, glycogen appeared in the epithelium of the digestive tract and the parenchyma of the pancreas. As development advanced, glycogen granules increased in number and size in these tissues, and they became evenly distributed in the epithelium of the digestive tract as either single particles or aggregates, as deduced by electron microscopy at late embryonic stages. Immunoreactivity specific both for BGP and for MBGP was detected in the digestive tract and the pancreas from stage 13. As development advanced, both BGP- and MBGP-immunoreactive cells increased in number and in immunoreactivity, and the number of MBGP-immunoreactive cells became larger than that of BGP-immunoreactive cells. By contrast, in hepatic cells, which serve as a major storage site for glycogen in adults, glycogen was detected only from stage 20, in smaller amounts, without formation of aggregates, and no immunoreactivity specific for BGP or MBGP was apparent throughout the embryonic stages examined. Thus, in the epithelium of the digestive tract and the parenchyma of the pancreas, but not in hepatic cells, the appearance and localization of GP coincided almost exactly with that of glycogen. These observations suggest that glycogen in the epithelium of the digestive tract and the parenchyma of the pancreas has not only been synthesized but also degraded from an early embryonic period and may, thus, be related to active cellular metabolism that is specific for embryonic development, including proliferation of the epithelium and interactions between epithelium and mesenchyme.     

Effect of geniposide,a hypoglycemic glucoside,on hepatic regulating enzymes in diabetic mice induced by a high-fat diet and streptozotocin

Aim： Hepatic glycogen phosphorylase （GP） and glucose-6-phosphatase （G6Pase） play an important role in the control of blood glucose homeostasis and are proposed to be potential targets for anti-diabetic drugs. Geniposide is an iridoid glucoside extracted from Gardenia jasminoides Ellis fruits and has been reported to have a hypoglycemic effect. However, little is known about the biochemical mechanisms by which geniposide regulates hepatic glucose-metabolizing enzymes. The present study investigates whether the hypoglycemic effect of geniposide is mediated by GP or G6Pase. Methods： Type 2 diabetic mice, induced by a high-fat diet and streptozotocin injection, were treated with or without geniposide for 2 weeks. Blood glucose levels were monitored by a glucometer. Insulin concentrations were analyzed by the ELISA method. Total cholesterol （TC） and triglyceride （TG） levels were measured using LabassayTM kits. Activities of hepatic GP and G6Pase were measured by glucose-6-phosphate dehydrogenase-coupled reaction. Real-time RT-PCR and Western blotting were used to determine the mRNA and protein levels of both enzymes. Results： Geniposide （200 and 400 mg/kg） significantly decreased the blood glucose, insulin and TG levels in diabetic mice in a dose-dependent manner. This compound also decreased the expression of GP and G6Pase at mRNA and immunoreactive protein levels, as well as enzyme activity. Conclusion： Geniposide is an effective hypoglycemic agent in diabetic mice. The hypoglycemic effect of this compound may be mediated, at least in part, by inhibiting the GP and G6Pase activities.     

In vitro study on intrathecal use of 5-fluoro-2′-deoxyuridine (FdUrd) for meningeal dissemination of malignant brain tumors

We investigated 5-fluoro-2-deoxyuridine (FdUrd) as a potential agent for intrathecal treatment of malignant brain tumors with meningeal dissemination. We examined the neurotoxicity of FdUrd in vitro using primary cultures of neurons from C57BL/6 mice (ED14). Tumoricidal activity was also studied in four glioma cell lines and one medulloblastoma cell line. In addition, thymidine phosphorylase (TPase) and thymidine kinase (TK), which are key enzymes for FdUrd metabolism, were measured in the cerebrospinal fluid (CSF) of 36 patients with brain tumors. The antitumor activity of FdUrd for murine glioma cells was approximately 20- to 200-fold higher than that of 5-fluorouracil (5-FU). Against human cell lines, it was 3- to 500-fold higher than that of 5-FU. The neurotoxic effect of FdUrd on cultured neurons was far less than that of 5-FU or 5-fluorouridine (FUrd). Cerebrospinal fluid contained no detectable thymidine phosphorylase in most patients with brain tumors. Several studies have indicated that FdUrd is rapidly converted to 5-FU in the presence of thymidine phosphorylase, so that a high dose of FdUrd must be administered to obtain good efficacy. However, a high dose FdUrd frequently cause severe toxicity. In contrast, the data obtained here suggest that no enzymatic conversion of FdUrd to 5-FU should occur in the CSF. In addition, FdUrd has an excellent antitumor activity and minimal neurotoxicity. We therefore conclude that intrathecal FdUrd is a potential therapy for CSF dissemination of malignant brain tumors.     

AFP启动子调控PNP载体的构建及分析

目的分别构建三种启动子调控的大肠杆菌嘌呤核苷磷酸化酶(PNP)基因表达载体,检测、分析三者的表达差异.方法构建三种启动子调控的PNP基因表达载体.将三个PNP基因载体转染不同细胞株,检测PNP基因在各细胞株中表达,分析三者表达的特点.结果AF 0.3和[HRE]AF调控的PNP基因在AFP阳性肝癌细胞中实现了靶向性表达,而且后者在AFP阴性肝癌细胞中也实现了靶向性表达.结论三种PNP基因表达载体的成功构建为利用PNP/MeP-dR系统进行肝癌的靶向性基因治疗打下坚实的基础.