Induction of the fibrinolytic system by cartilage extract mediates its antiangiogenic effect in mouse glioma

Both the antiangiogenic and antitumoral activity of shark cartilage extracts (SCE) have been demonstrated in animal models and clinical trials. Studies reported that SCE induces the expression of tissue plasminogen activator gene (PLAT) in endothelial cells and increases the activity of the protein (t-PA) in vitro. The aim of this study was to demonstrate the crucial role of t-PA induction in the antiangiogenic and antitumor activity of SCE in experimental glioma. This study showed antiangiogenic and antitumoral effects of SCE in three mice glioma models (C6, HGD and GL26). Histological examination suggested perivascular proteolysis and edema as well as important intratumoral necrosis, which artefactually increased the tumor volume at high doses. Thus, the antiangiogenic effect of SCE correlated with the presence of t-PA and angiostatin in degenerating vessels. Functional in vivo experiments were conducted to modulate the plasminogen pathway. No antiangiogenic effect was observed on tumors overexpressing the plasminogen activator inhibitor-1 (PAI-1). Moreover, therapeutical effects were neutralized in mice that were cotreated with ε-aminocaproic acid (EACA, 120 mg/kg p.o.), an inhibitor that blocks the high-affinity lysine binding sites of both plasminogen and plasmin. In contrast, cotreatment with N-acetylcysteine (NAC, 7,5 mg/kg i.p.), a sulfhydril donor that reduces plasmin into angiostatin or other antiangiogenic fragments, increased the benefit of SCE on mice survival. In subcutaneous models, NAC prevented the increase in tumor volume caused by high doses of cartilage extract. In conclusion, this study indicates that induction of t-PA by shark cartilage extract plays an essential role in its antiangiogenic activity, but that control of excessive proteolysis by a plasmin reductor could prevent edema and uncover the full benefit of shark cartilage extract in the treatment of intracranial tumors.     

Angiogenesis and antiangiogenic therapy in endometriosis

Endometriosis, the presence of endometrium-like tissue outside of the uterine cavity, is a common disease among women of reproductive age. Typical symptoms include abdominal pain and painful menstruation. In addition, endometriosis is associated with reduced fertility. Current treatment modalities, the surgical removal of endometriotic lesions and the hormonal suppression of estrogen are associated with significant morbidity, side-effects and recurrence rates. Despite uncertainties about the pathophysiology of the disease it has recently become apparent that angiogenesis plays a pivotal role in endometriosis. This review focuses on a multitude of factors involved in the angiogenic phenotype of endometriosis demonstrating that many biological systems such as the immune system and steroid hormones are closely connected to angiogenic pathways in this disease. In addition, experimental and clinical data are discussed that concentrate on the inhibition of angiogenesis as a novel therapeutic approach for endometriosis.     

脑胶质瘤多药耐药机制的研究

为提高脑胶质瘤的化疗疗效 ,探讨胶质瘤的耐药机制 ,利用已建立的胶质瘤多药耐药细胞株 (C6 /adr) ,采用 RT- PCR法、免疫组织化学法分别对 C6及 C6 / adr细胞株 mdr- 1基因及其编码产物 P糖蛋白 (Pgp)进行了定性研究 ,同时采用流式细胞免疫学方法分别进行耐药蛋白及靶酶定量分析。结果显示 ,C6 mdr- 1基因表达阴性 ,C6 / adr mdr- 1基因表达阳性 ;C6 / adr Pgp强阳性 ,主要位于细胞膜及突起上。 C6、C6 / adr中的 Pgp分别为4.17%± 0 .6 3%、40 .5 9%± 4.77%(P<0 .0 1) ;其肺阻蛋白 (L RP)分别为 2 .92 %± 0 .2 2 %、2 1.17%± 1.79%(P<0 .0 1) ;拓扑异构酶 α(TOPO α)分别为 2 2 .88%± 1.94%、16 .77%± 1.0 8%(P>0 .0 5 ) ;谷胱甘肽 S-转移酶л(GST- л)分别为 5 .93%± 0 .78%、31.81%± 8.76 %(P<0 .0 1)。认为 Pgp、多药耐药相关蛋白 (MRP)、L RP在耐药胶质瘤中可共同表达 ,Pgp、MRP、L RP、GST-л在胶质瘤继发性耐药中起重要作用 ,测定其变化有助于化疗药物的选择。     

Recurrence or metastasis of HCC:predictors, early detection and experimental antiangiogenic therapy

AIM To investigate the predictors for recurrence or metastasis of HCC, and to evaluate the effect of antiangiogenic therapy on the growth of transplantable human HCC in nude mice. METHODS RT-PCR was used to measure the expression of matrix metalloproteinase-9 (MMP-9) and vascular endothelial growth factor (VEGF) in 56 pairs of nontumorous liver and tumor samples. Sixty blood samples from human HCC were examined by nested RT-PCR to find out AFP mRNA. Recombinant human endostatin and polyclonal antibody against VEGF were administered to treat human HCC transplanted in nude mice. RESULTS Thirty of 56 HCC samples showed stronger expression of MMP-9 in tumorous tissues than in nontumorous tissues. Fifteen of the 26 patients with relative expression level of MMP-9 more than 0.34 developed tumor recurrence or metastasis, whereas only 7 of 30 patients with relative expression level less than 0.34 developed tumor recurrence (P＜0.05).There was no significant difference in the relative expression level of VEGF between patients with postoperative recurrence or metastasis and those without recurrence. AFP mRNA was detectable in 53.3% of patients with HCC. The sensitivity and specificity of AFP mRNA as a marker to detect hematogenous dissemination of HCC cells was 81.8% and 84.4%, respectively. Recombinant human endostatin and polyclonal antibody against VEGF inhibited the growth of transplantable HCC in nude mice by 52.2% and 45.7%, respectively.CONCLUSION MMP-9 expression in HCC correlates with the postoperative recurrence or metastasis of HCC. Patients with high level of MMP-9 expression in HCC are susceptible to metastasis. AFP mRNA could serve as an indicator of hematogenous spreading of HCC cells in circulation and a predictor of recurrence or metastasis of HCC. Antiangiogenesis may be an adjuvant therapy for HCC.     

肿瘤血管生成及其抗血管生成治疗的研究进展

肿瘤的生长和转移依赖于新生血管形成,血管内皮生长因子及其受体是目前发现的最重要的促肿瘤血管生长因子,在肿瘤血管生成过程中发挥关键作用。鉴于肿瘤血管生成在肿瘤生长、浸润和转移中的重要作用,近年来开始了抗血管生成治疗肿瘤的新方法——抗血管生成疗法。本文着重综述了肿瘤血管生成及其抗肿瘤血管生成治疗的研究进展。     

Angiogenesis and antiangiogenic therapy in hematologic malignancies

Angiogenesis, the generation of new blood capillaries from preexisting blood vessels, is tightly regulated in the adult organism. Although many of the initial studies were performed on solid tumors, increasing evidence indicates that angiogenesis also plays an important role in hematologic malignancies. Overexpression of angiogenic factors in particular VEGF and bFGF in most hematologic malignancies may explain the increased angiogenesis found in these malignancies and correlate with poor prognosis as well as decreased overall survival. In this review, we focus on the current literature of angiogenesis and antiangiogenic therapy in hematologic malignancies, and finally describe advances and potential challenges in antiangiogenic treatment in hematologic malignancies.     

Toll-like receptor 4 on stromal and hematopoietic cells mediates innate resistance to uropathogenic Escherichia coli

Innate host defenses at mucosal surfaces are critical in the early stages of many bacterial infections. In addition to cells of the traditional innate immune system, epithelial cells can also produce inflammatory mediators during an infection. However, the role of the epithelium in innate host defense in vivo is unclear. Recent studies have shown that lipopolysaccharide (LPS) recognition is critical for bladder epithelial cells to recognize and respond to Escherichia coli. Moreover, the LPS-nonresponsive mouse strain C3HHeJ, which has a mutation in the primary LPS receptor, Toll-like receptor 4 (TLR4), is extremely susceptible to infection with uropathogenic strains of E. coli. In this study, a bone marrow transplant approach was used to investigate the specific contributions of the bladder epithelium (and other stromal cells) in the TLR4-mediated innate immune response to the invading E. coli pathogen. Mice expressing the mutant TLR4 in the epithelialstromal compartment were not able to mount a protective inflammatory response to control the early infection even when their hematopoietic cells expressed wild-type TLR4. However, the presence of TLR4(+) epithelialstromal cells was not sufficient to activate an acute inflammatory response unless the hematopoietic cells were also TLR4(+). These results demonstrated that bladder epithelial cells play a critical role in TLR4-mediated innate immunity in vivo during a mucosal bacterial infection.     

抗肺癌血管生成治疗的进展

没有血管生成,实体瘤直径不会超过3mm。肿瘤的生长和转移都依赖于新生血管的形成。抗肿瘤血管生成治疗是近年来逐渐兴起的一种新的抗癌方法,肿瘤血管生成的机制也成为近年来肿瘤领域研究的热点。本文就两年来抗肺癌肿瘤血管生成治疗进展作一综述。     

Interfering with hemostatic system components: possible new approaches to antiangiogenic therapy

Inhibition of angiogenesis has progressed from a theoretical and esoteric discipline scrutinized in but a few laboratories far removed from the clinic, to mainstream experimental clinical cancer therapeutics. Dramatic progress in this field represents a triumph of the concept of translational biomedical research. Growth of knowledge in this discipline has brought to light a bewildering yet tantalizing array of interacting enzymatic algorithms that participate in the highly orchestrated process of new blood vessel formation critical for tumor growth and dissemination. It is clear that pathways of blood coagulation (in broad context) and angiogenesis are inextricably linked. The facts that much is already known about many components of these pathways and that stalling of tumor growth has already been demonstrated for several interventions aimed at participants in these reactions send a clear signal that more effective and less toxic cancer therapy may be at hand in the near future. There is no lack of candidate targets for intervention brought to light by preclinical scientists. Numerous well-characterized investigational agents are on hand for testing. The challenge is clearly in the hands of the clinical investigators to proceed with human intervention studies while armed with knowledge of opportunities and pitfalls that should guide insightful clinical trial design. A particularly compelling feature of this treatment paradigm is that it is not aimed directly at destruction of tumor through inhibition of the DNA replication machinery of the cell. Rather it is aimed at restoring the normal state by modulating the dysregulated interaction of tumor cells with their environment that is characteristic of cancer.     

GSTpi expression mediates dopaminergic neuron sensitivity in experimental parkinsonism

The cause of 95% of Parkinson's disease (PD) cases is unknown. It is hypothesized that PD arises from an interaction of free-radical-generating agents with an underlying genetic susceptibility to these compounds. Here we use the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine model of parkinsonism to examine the role of a dual function protein, GSTpi, in dopaminergic neuron death. GSTpi is the only GST family member expressed in substantia nigra neurons. GSTpi reduction by pharmacological blockade, RNA inhibition, and gene targeting increases sensitivity to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, suggesting that differential expression of GSTpi contributes to the sensitivity to xenobiotics in the substantia nigra and may influence the pathogenesis of reactive oxygen species-induced neurological disorders including PD.     

EphB4在食管癌组织中的表达及临床意义

目的 探讨EphB4在食管癌发生、发展中的作用及机制.方法 采用实时荧光定量PER和免疫组织化学染色法对96例食管癌患者癌组织和癌旁正常组织EphB4水平进行测定.结果 食管癌组织中EphB4 mRNA阳性率、EphB4 mRNA及其蛋白表达水平显著高于癌旁正常组织(P均=0,000);癌组织中EphB4 mRNA表达水平与淋巴结转移、家族史、肿瘤体积、肿瘤分期及肿瘤位置有关(P均<0.05).结论 EphB4在食管癌发展过程中起重要作用;可作为监测病情、判断预后的指标.     

Tandem gene amplification mediates copper resistance in yeast.

Resistance to copper's toxicity in yeast is controlled by the CUP1r locus. This gene was cloned by transforming sensitive recipients (cup1(8)) with a collection of hybrid DNA molecules, consisting of random yeast DNA fragments inserted into the vector YRp7. Four resistant transformants were studied in detail. Autonomously replicating or integrated by homologous recombination into chromosomal sites, the corresponding plasmids and several subclones confer resistance on sensitive recipients carrying the natural variant allele, cup1(8). Tetrad analysis and genetic mapping established that integration occurs typically at the cup1(8) site located 28 centimorgans distal to thr1, a chromosome VIII marker. Restriction endonuclease cleavage and electrophoretic mobility studies revealed that the CUP1r locus consists of a tandem array of repetitive units. Each unit is 1.95 kilobases in length and contains single sites for Kpn I and Xba I and two Sau3A sites. The sensitive allele represents one repeat and the resistant allele embraces 15 tandemly arrayed repeat units. Progressive selections in higher copper concentrations establish strains with markedly enhanced resistance. Resistance, we propose, is mediated by a gene amplification mechanism based on unequal sister chromatid exchange.     

Ribosome clearance by FusB-type proteins mediates resistance to the antibiotic fusidic acid

Resistance to the antibiotic fusidic acid (FA) in the human pathogen Staphylococcus aureus usually results from expression of FusB-type proteins (FusB or FusC). These proteins bind to elongation factor G (EF-G), the target of FA, and rescue translation from FA-mediated inhibition by an unknown mechanism. Here we show that the FusB family are two-domain metalloproteins, the C-terminal domain of which contains a four-cysteine zinc finger with a unique structural fold. This domain mediates a high-affinity interaction with the C-terminal domains of EF-G. By binding to EF-G on the ribosome, FusB-type proteins promote the dissociation of stalled ribosome⋅EF-G⋅GDP complexes that form in the presence of FA, thereby allowing the ribosomes to resume translation. Ribosome clearance by these proteins represents a highly unusual antibiotic resistance mechanism, which appears to be fine-tuned by the relative abundance of FusB-type protein, ribosomes, and EF-G.     

Headway in resistance to endocrine therapy in breast cancer

Resistance to endocrine therapy is the major problem for ERα(+) breast cancer patients. Research in endocrine resistance, mainly based on breast cancer cell lines and transplantation animal models, has indicated that phosphorylation of estrogen receptors, high expression of SRC and high activation of ErbB/MAPK pathway are the 3 main mechanisms for occurrence of endocrine resistance. Restoration of ER expression and exploration of inhibitors to various biological targets are the 2 promising ways to solve this problem. Further research is needed to deeply explore relevant mechanisms and resolvents so as to guide clinical practice.     

ABCG2 is related with the grade of glioma and resistance to mitoxantone, a chemotherapeutic drug for glioma

Objective  The aim of this study is to explore if ABCG2 is related to the grade of glioma and resistance to chemotherapeutic drug for glioma. Methods  The ABCG2 expression and distribution among glioma tissues of different grades and other samples were examined using tissue microarray technique. The enhancement of sensitivity of CD133+ glioma stem cells to chemotherapeutic agent, mitoxantone through addition of ABCG2 competitive inhibitor nicardipine was testified by MTT assay and FACS analysis. Results  The positive immunostaining of ABCG2 was observed in less than 10% of low-grade gliomas (3/31 in grade I + II) and in more than 40% of high-grade gliomas (16/37 in grade III + IV), which was statistically different (χ ² = 10.710, P = 0.0011). In samples consisting of glioma stem cells (CD133+), the positive-straining rate was 100% (4/4), while in CD133− fraction, no positive staining was observed. A simultaneous treatment of CD133+ tumor cells with concentration-dependent mitoxantone (10⁻⁵–1 μM) and 2.5/5.0 μM nicardipine resulted in synergistic cytotoxicity. The apoptotic rate of CD133+ cells treated with mitoxantone plus nicardipine was significantly higher than that treated with mitoxantone alone (58.54 ± 7.06% vs. 30.7 ± 3.79%, P < 0.01). Conclusions  Our results showed that ABCG2 is also expressed in glioma stem cells and the expression level of ABCG2 is positively associated with the increasing pathological grade of glioma (poor cell differentiation). ABCG2 plays a key role in glioma cells resistance to mitoxantone, chemotherapeutic drug for glioma. Thus, inhibition of ABCG2 protein activity by nicardipine in glioma can sensitize it to mitoxantone, which may lead to better treatment strategies for cancers. Y. Jin and Z. Q. Bin contributed equally to this paper.