Role of vincristine in the inhibition of angiogenesis in glioblastoma

Objective: Vincristine, a microtubule-destabilizing drug, was found to exhibit anti-angiogenic effects and anti-tumoral activity. However, the precise mechanism by which vincristine inhibits angiogenesis in glioblastomas is not well understood. Our aim was to investigate whether vincristine affects vascular endothelial growth factor (VEGF) expression in glioblastoma cells and determine whether it is mediated by the downregulation of hypoxia-inducible factor-1α (HIF-1α).

Methods: We investigated the expression of HIF-1α in glioblastoma tissues resected from patients and in human glioblastoma cell lines using immunohistochemistry, Western blot analysis, and immunocytochemistry. In addition to an MTT assay assessing the effect of vincristine on cell proliferation and viability, the effects of vincristine on VEGF mRNA expression and HIF-1α protein were examined using real-time RT-PCR and Western blot analysis under 1% O₂ (hypoxia).

Results: HIF-1α was expressed in the majority of glioblastoma tissues and was detected mainly in the nucleus. Strong immunoreactivity for HIF- 1 α was found often in the hypercellular zones. Under hypoxic conditions, HIF-1α protein levels in the glioblastoma cell lines increased, primarily localizing into the nucleus similar to glioblastoma tissues. Exposure of glioblastoma cells to vincristine resulted in enrichment of the G₂-M fraction of the cell cycle, which suggests that vincristine-mediated growth inhibition of glioblastoma is correlated with mitotic inhibition. Using doses lower than those found to reduce the viability and proliferation of cells by 50% (IC₅₀), vincristine decreased both the expression of VEGF mRNA and the level of HIF-1α protein in hypoxic glioblastoma cells. In addition, following exposure to vincristine, the expression of VEGF mRNA was correlated with HIF-1α protein levels.

Conclusions: Our results suggest that the mechanism by which vincristine elicits an anti-angiogenic effect in glioblastomas under hypoxic conditions might be mediated, in part, by HIF-1α inhibition.     

Identification of novel hypermethylated genes and demethylating effect of vincristine in colorectal cancer

Background

Colorectal cancer (CRC) arises as a consequence of genetic events such as gene mutation and epigenetic alteration. The aim of this study was to identify new hypermethylated candidate genes and methylation-based therapeutic targets using vincristine in CRC.

Methods

We analyzed the methylation status of 27,578 CpG sites spanning more than 14,000 genes in CRC tissues compared with adjacent normal tissues and normal colon tissues using Illumina bead chip array. Twenty-one hypermethylated genes and 18 CpG island methylator phenotype markers were selected as candidate genes. The methylation status of 39 genes was validated by quantitative methylation-specific polymerase chain reaction in CRC tissues, adjacent normal tissues, normal colon cells, and three CRC cell lines. Of these, 29 hypermethylated candidate genes were investigated using the demethylating effects of 5-aza-2′-deoxycytidine (5-aza-dC) and vincristine in CRC cells.

Results

Thirty-two out of 39 genes were hypermethylated in CRC tissues compared with adjacent normal tissues. Vincristine induced demethylation of methylated genes in CRC cells to the same extent as 5-aza-dC. The mRNA expression of AKR1B1, CHST10, ELOVL4, FLI1, SOX5, STK33, and ZNF304 was restored by treatment with 5-aza-dC and vincristine.

Conclusion

These results suggest that these novel hypermethylated genes AKR1B1, CHST10, ELOVL4, SOX5, STK33, and ZNF304 may be potential methylation biomarkers and therapeutic targets of vincristine in CRC.     

The biological and clinical basis for early referral of low grade glioma patients to a surgical neuro-oncologist

The discovery of IDH1/2 (isocitrate dehydrogenase) mutation in large scale, genomewide mutational analyses of gliomas has led to profound developments in understanding tumourigenesis, and restructuring of the classification of both high and low grade gliomas. Owing to this progress made in the recognition of molecular markers which predict tumour behavior and treatment response, the increasing importance of adjuvant treatments such as chemo- and radiotherapy, and the tremendous advances in surgical technique and intraoperative monitoring which have facilitated superior extents of resection whilst preserving neurological functioning and quality of life, contemporary management of low grade glioma (LGG) has switched from a passive, observant approach to a more active, interventional one. Furthermore, this has implications for the manner in which patients with incidentally discovered and/or asymptomatic LGG are managed, and this review of the biological behaviour of LGG, as well as its clinical investigation and management, should act as a timely reminder to all clinicians of the importance of referring LGG patients early to a surgical neuro-oncologist who is not only familiar and acquainted with the vagaries of this disease process, but who, in addition, is devoted to delivering care to these patients with the support of a multi-disciplinary clinical decision-making unit, comprising medical neuro-oncologists, radiation oncologists and allied health professionals.     

中药活性成分逆转肿瘤细胞多药耐药作用的体外筛选

①目的 从多种中药单体或提取物中筛选肿瘤细胞多药耐药(MDR)逆转剂。②方法 采用MTT法进行药物细胞毒实验及筛选与逆转作用研究。③结果 黄芩甙、甘糖酯、茶多酚、苦参碱，在已出现明显细胞毒性的剂量下，仍未显示对长春新碱(VCR)耐药的逆转作用。钩藤总碱5.0μg／ml，药根碱2μg／ml(5．9μM)，靛玉红1．25μg／ml(4．8μM)，姜黄素1．56fμg／ml(17μ)、对VCR耐药的逆转倍数分别为l6．8倍、5．1倍、4倍及1．97倍。而在亲本KB细胞，除了姜黄素外，其它3种药物对VCR细胞毒性无明显影响。④结论 钩藤总碱、药根碱、靛玉红对KBv200细胞耐药具有逆转作用，而姜黄素与VCR合用在KB及KBv200细胞均有增敏作用。     

Successful treatment with vincristine in PHACES syndrome

Abstract We report a case of PHACES syndrome witch was effectively treated using vincristine. A female infant was referred at 8 months of age for evaluation with a segmental mandibular haemangioma with rapid growing and facial disfigurement. The infant was initially placed on oral prednisone with clinical response but she developed obstructive sleep apnoea. Vincristine was started at about 24 months and continued for 4 months with marked decrease in the size of the haemangioma. The only side effect was constipation.     

Augmentation of vincristine cytotoxicity by megestrol acetate

 Purpose: To determine the effect of a semisynthetic progesterone, megestrol acetate (MA), on the cytotoxicity of various chemotherapeutic agents including vincristine, doxorubicin, actinomycin-D, taxol, vinblastine and colchicine in cell lines with or without P-gp expression. Methods: Three cell lines with high P-gp expression (two colon cancer and one leukemia), and a control cell line with no P-gp expression were exposed to chemotherapeutic agents in the presence or absence of MA and drug sensitivity was determined using the MTT colorimetric assay. P-gp-170 expression was detected by flow cytometry using JSB-1 monoclonal antibody and the functionality of MDR expression was tested by rhodamine-123 uptake studies. In vitro drug accumulation studies were performed using [³H]-vincristine. The results were subjected to paired t-test analysis and 95% confidence intervals were determined in cytotoxicity tests. Results: MA augmented the cytotoxicity of vincristine, but not doxorubicin, actinomycin-D, taxol, vinblastine or colchicine in the three P-gp-expressing cell lines, whereas verapamil augmented the cytotoxicity of doxorubicin and vincristine. MA did not augment the cytotoxicity of vincristine in the P-gp-negative HUT-102 cell line. Conclusion: MA augmented vincristine cytotoxicity in P-gp-expressing cell lines. However, this phenomenon did not occur with the other classic MDR drugs. Therefore, the augmentation of vincristine cytotoxicity by MA can be explained either by involvement of a different mechanism that coexists with the mdr-1 phenotype or by the presence of a different affinity or binding site on the P-gp molecule for MA compared to that for the other classic MDR drugs and verapamil. Received: 8 September 1995 / Accepted: 3 June 1996     

Vincristine and focal segmental sclerosis: do we need a multicentre trial?

Over the last 10 years, eight children have received vincristine for the treatment of steroid- and cyclophosphamide-resistant nephrotic syndrome at Great Ormond Street Hospital for Children, London. We present our experience of these eight cases and put forward a case for reassessing the effectiveness of vincristine in this disorder. In our series, two children treated with vincristine achieved complete remission with preserved renal function, including relapses in one. Both had primary steroid- and cyclophosphamide-resistant focal segmental glomerulo sclerosis (FSGS). Of the other cases, four also had primary FSGS, one familial FSGS and one mesangioproliferative glomerulonephritis. We discuss in general the pros and cons of vincristine therapy in nephrotic syndrome versus the cytotoxic agents that are currently used and the differences in clinical features among the responders and non-responders in this small group. In addition, we explore why this may have occurred and summarise the literature over the last 25 years, where vincristine appeared to have been beneficial, especially in secondary forms of nephrotic syndrome associated with malignancy. We conclude that vincristine therapy warrants re-examination as it could be a valuable alternative therapeutic agent in some cases of FSGS with relatively minor side effects. Received September 1, 1997; received in revised form December 12, 1997; accepted December 15, 1997     

长春新碱对大鼠小肠肌电及动力的影响

目的 探讨抗肿瘤药长春新碱(VCR)对清醒大鼠小肠肌电和动力及相关机制的影响.方法 SD大鼠72只,分为6组,A组为对照组(n=18),尾静脉注射0.9%氯化钠溶液;B组为VCR尾静脉注射组,按给药剂量分为0.25 mg/kg(n=6)、0.5 mg/kg(n=6)和0.75 mg/kg(n=18)组;C组为假手术组(n=6),仅剖腹,尾静脉注射0.9%氯化钠溶液;D组为假手术+VCR 0.75 mg/kg(n=6);E组为双侧膈下迷走神经切断+0.9%氯化钠溶液(n=6);F组为双侧膈下迷走神经切断+VCR 0.75 mg/kg(n=6).观察用药后大鼠小肠的肌电及动力变化.采用生物机能实验系统记录小肠慢波频率、曲线下面积,移行性复合运动(MMC)周期、MMC Ⅲ相持续时间;测定小肠推进率,免疫荧光染色观察肠肌间神经元及Cajal间质细胞的表达.结果 VCR 0.25 mg/kg组对小肠动力无明显改变.0.5和0.75 mg/kg组均出现小肠肌电活动异常,且随作用时期不同表现不同,静脉注射(51.00±14.27)min后MMC模式被连续性峰电取代,(78.33±13.08)min后MMC逐渐恢复,0.5和0.75 mg/kg组MMC周期分别为(343.17±142.93)s和(302.67±66.67)s,较A组[(740.22±98.92)s]缩短(F=31.325,P<0.01).用药后第3天,0.5和0.75 mg/kg组曲线下面积为(2.56±0.30)mV·s和(2.57±0.56)mV·s,较A组降低[(4.04±0.64)mV·s,F=11.442,P<0.01].用药第3天,VCR 0.75 mg/kg组小肠推进率为(33.59±1.43)%,较A组减慢[(60.34±2.41)%,t=23.360,P<0.01].迷走神经切断组用药当日仍保持MMC相模式,第3天出现不规则峰电活动及慢波节律紊乱,VCR组曲线下面积为(2.49±0.33)mV·s,较A组降低[(4.10±0.80)mV·s,t=4.549,P=0.001].用药第3天,VCR 0.75 mg/kg组Cajal间质细胞阳性面积比为(5.84±3.11)%,较A组减少[(24.90±1.86)%,t=20.357,P<0.01];肠肌间神经元阳性面积比为(14.37±2.00)%,与A组比较差异无统计学意义[(14.17±2.63)%,P>0.05].结论 VCR改变小肠肌电活动及动力,并与剂量及时间相关.推测初期是通过迷走神经通路增强小肠运动,后期损伤Cajal间质细胞,导致小肠动力减弱.     

Veno-occlusive disease of the liver during induction therapy for acute lymphoblastic leukemia

Veno-occlusive disease (VOD) of the liver, also termed as sinusoidal obstruction syndrome, constitutes a well-known complication of high-dose cytoreductive chemotherapy prior to allogeneic or autologous bone marrow transplantation and is associated with the intensity of treatment [1]. On the contrary, there is only one report of VOD during induction therapy for acute lymphoblastic leukemia in a patient with Marfan syndrome, who was successfully treated with defibrotide [2]. In this article, we present the first fatal case of VOD during induction therapy for acute lymphoblastic leukemia.     

Advanced Breast Angiosarcoma Completely Responding to Gemcitabine-Containing Chemotherapy

Background

For patients with anthracycline-resistant metastatic angiosarcoma, there is currently no available standard for second-line therapy, and a need exists for novel effective regimens to improve response rates.

Case Report

We report here on a case of a primary angiosarcoma of both breasts in a 34-year-old woman presenting with lung metastases. Upon completion of 3 cycles of the MAID regimen (mesna, adriamycin, ifosfamide, dacarbazine), computed tomography showed disease progression. Subsequently, a second-line chemotherapy was started using the GVP regimen (gemcitabine, vincristine, cisplatin). Complete response of the lung metastases was achieved after 6 cycles of treatment.

Conclusion

In the absence of an effective therapy among patients with anthracycline-resistant metastatic breast angiosarcoma, a GVP chemotherapy regimen can be performed as a selective option.