Therapeutic strategies involving survivin inhibition in cancer

Survivin is a small protein that belongs to the inhibitor of apoptosis protein family. It is abundantly expressed in tumors compared with adult differentiated tissues, being associated with poor prognosis in many human neoplasms. This apoptotic inhibitor has a relevant role in both the promotion of cancer cell survival and in the inhibition of cell death. Consequently, aberrant survivin expression stimulates tumor progression and confers resistance to several therapeutic strategies in a variety of tumors. In fact, efficient survivin downregulation or inhibition results in spontaneous apoptosis or sensitization to chemotherapy and radiotherapy. Therefore, all these features make survivin an attractive therapeutic target to treat cancer. Currently, there are several survivin inhibitors under clinical evaluation, although more specific and efficient survivin inhibitors are being developed. Moreover, novel combination regimens targeting survivin together with other therapeutic approaches are currently being designed and assessed. In this review, recent progress in the therapeutic options targeting survivin for cancer treatment is analyzed. Direct survivin inhibitors and their current development status are explored. Besides, the major signaling pathways implicated in survivin regulation are described and different therapeutic approaches involving survivin indirect inhibition are evaluated. Finally, promising novel inhibitors under preclinical or clinical evaluation as well as challenges of developing survivin inhibitors as a new therapy for cancer treatment are discussed.     

Complement inhibition as a therapeutic strategy in retinal disorders

Introduction: Dry age-related macular degeneration (AMD) and Stargardt Macular Dystrophy (STGD1) result in vision loss due to progressive atrophy of the macula and lack of effective treatments. Numerous studies have implicated complement-associated inflammation as a contributor to both diseases.

Areas covered: The complement factor D inhibitor, lampalizumab, failed to halt geographic atrophy (GA) progression in phase 3 studies. The complement factor 3 (C3) inhibitor, APL-2, has shown potential to reduce GA growth in a phase 2 trial, supporting advancement to phase 3 trials. The intravenous complement factor 5 (C5) inhibitor, eculizumab, failed to halt GA progression in a phase 2 study. Another C5 inhibitor, avacincaptad pegol, is delivered by intravitreal injection, and will be studied for safety and preliminary signs of efficacy for AMD and STGD1 patients in phase 2 trials. LFG316 (C5 inhibitor) and CLG561 (properdin inhibitor) failed to halt GA progression in phase 2 studies. A phase 1 trial is evaluating the effects of combining LFG316 and CL561. Complement inhibition by gene therapy will be explored in the phase 1 trial of HMR59 in AMD patients.

Expert opinion: While complement inhibition has not yet demonstrated the ability to halt GA progression in a phase 3 trial, further study is warranted.     

Antisense inhibition of ICAM-1 expression as therapy provides insight into basic inflammatory pathways through early experiences in IBD

Background: Alicaforsen (ISIS 2302), an antisense to intercellular adhesion molecule-1 (ICAM-1) (CD54), was designed to inhibit ICAM-1 expression. ICAM-1 seems to play a role in cell-mediated inflammation, specifically cell trafficking. For this reason, it may be useful in a variety of immune-mediated diseases, including inflammatory bowel disease. Objective: To evaluate the use of alicaforsen in clinical trials to understand its efficacy and side effects, as well as assess for evidence that may offer insight into disease pathways. Methods: We evaluate all of the available, published trials, with a focus on the prospective, randomized trials. Results/conclusions: Systemic treatment for Crohn's disease has not revealed significant effect. Topical enemas for ulcerative colitis have demonstrated some effect in secondary outcomes, and initial studies in pouchitis are promising. In general, the compound has been well tolerated and safe.     

宫颈癌组织中survivin基因的表达及其临床意义

目的 :探讨宫颈癌组织中survivin基因表达的特征及其临床意义。方法 :应用免疫组织化学方法 (SP法 )检测survivin基因在 41例宫颈癌组织、17例CIN宫颈组织及 10例正常宫颈组织中的表达 ,分析其与临床病理特征的相关性及其与预后的关系。结果 :宫颈癌组织中survivin的阳性表达率较正常组织及CIN均明显升高 (P <0 0 5 ) ;宫颈癌患者中survivin阳性表达的中位生存期明显小于阴性表达者 (P <0 0 5 )。Survivin的表达与宫颈癌的临床分期、病理分级及组织类型无关。结论 :survivin的阳性表达增高与宫颈癌的发生密切相关 ,预示预后不良。     

靶向干扰Survivin基因对结直肠癌细胞PTTG蛋白的影响

目的探讨重组载体介导的Survivin小干扰RNA(siRNA)对人结肠癌细胞株Lovo中PTTG蛋白的影响。方法运用靶向Survivin siRNA真核表达载体转染结肠癌Lovo细胞,western blot检测PTTG蛋白的表达水平。结果 Survivin基因沉默后24-72h,与正常对照组相比,Survivin和PTTG蛋白表达均明显降低,差异具有统计学意义(P<0.01)。结论 Survivin基因沉默后结直肠癌细胞PTTG蛋白表达显著下调,提示Survivin和PTTG可能相互促进共同参与结直肠癌的发生发展。     

乳腺癌超声表现与survivin mRNA表达的相关性

目的：探索乳腺癌的超声声像表现与survivin mRNA表达之间的相关性。方法：收集46例乳腺癌患者病例,手术前进行高频超声,彩色多普勒血流显像（CDFI）检查,术后应用逆转录－聚合酶链反应（RT-PCR）方法检测肿瘤标本中survivin mRNA的表达,分析超声表现与基因表达之间的关系。结果：超声表现“毛刺征”与survivin mRNA表达相关;腋淋巴结肿大与survivin mRNA表达相关;CDFI血流信号丰富与survivin mRNA阳性表达相关;频谱多普勒表现高流速与survivin mRNA阳性表达相关（P均<0.05）;而肿瘤大小、“衰减征”、“钙化征”等与survivin mRNA表达无明显相关性（P>0.05）。结论：乳腺癌的部分声像特征与survivin mRNA表达存在相关性。     

Drug evaluation: Reolysin--wild-type reovirus as a cancer therapeutic

Oncolytics Biotech is developing an oncolytic reovirus therapy (Reolysin, Reosyn) for the potential treatment of a variety of Ras-mediated cancers, including glioma and medulloblastoma, pancreatic, prostate, breast, lung, colon, bladder, ovarian and hematological cancers, and melanoma and childhood sarcoma. Phase I/II clinical trials in recurrent malignant glioma began in 2002.     

Antisense oligonucleotide inhibition of Bcl-xL and Bid expression in liver regulates responses in a mouse model of Fas-induced fulminant hepatitis

Activation of the cell-surface receptor Fas can lead to apoptosis in parenchymal cells in the liver, and if severe enough, result in fulminant hepatic failure and animal death. In the present study, we have examined the roles played by the Bcl-2 family members Bcl-xL and Bid in regulating this response. To do this, we have developed chemically modified 2'-O-(2-methoxy) ethyl antisense inhibitors of both Bid and Bcl-xL expression. In Balb/c mice, dosing with these antisense oligonucleotides reduced expression of the targeted mRNA by greater than 80% in the liver. This reduction was highly dependent upon oligonucleotide sequence and oligonucleotide dose. Reduction of Bcl-xL expression resulted in a potentiation of Fas-mediated apoptosis in liver and significant increase of the lethality of Fas-mediated fulminant hepatitis (p < 0.0001). In contrast, reduction of Bid expression protected the animals against Fas-mediated fulminant hepatitis and death (p < 0.0001). Simultaneous dosing of mice with Bcl-xL and Bid-targeting antisense oligonucleotides resulted in an inhibition of expression of both targeted proteins and protection of the animals from Fas-mediated apoptosis. These results demonstrate, for the first time, the role of Bcl-xL in regulating responses to proapoptotic Fas signaling in mouse liver. In addition, this is the first reported example demonstrating the ability of antisense inhibitors to reduce expression of multiple proteins in animals by simultaneous dosing.     

人Survivin蛋白的纯化、单克隆抗体的制备及在肿瘤细胞的表达

目的表达人Survivin重组蛋白、制备单克隆抗体及检测Survivin在多种肿瘤细胞中的表达。方法诱导含有pMS-Survivin重组质粒的E.coli.表达人MS2-Survivin重组蛋白,并作为抗原免疫BALB/c小鼠,取其脾细胞与Sp2/0骨髓瘤细胞融合,经ELISA双筛,获得稳定分泌抗人Survivin mAb的杂交瘤细胞株。ELISA检测Survivin mAb的特异性。免疫细胞化学检测多种肿瘤细胞中天然Survivin的表达情况。结果诱导菌在相对分子质量为30KD左右表达出一新的蛋白条带。筛选出2株稳定分泌特异性抗人Survivin mAb的杂交瘤细胞株,亚类鉴定均为IgG1类。两株单克隆抗体的效价均达到6.4×105。ELISA结果显示出抗人Survivin mAb的特异性。在胃癌细胞、肺癌细胞、宫颈癌细胞中均强表达,且主要在细胞浆中。结论成功制备出特异性抗人Survivin mAb,为以后应用于临床检测奠定了基础,也为其进一步开发成诊断性试剂盒奠定了基础。     

Notch signaling pathway as a therapeutic target in breast cancer

The highly conserved Notch signaling pathway is involved in regulating a number of key cellular processes. This pathway has been implicated in both the development and progression of breast cancer and has emerged as a possible therapeutic target. Several clinical trials are currently underway to determine if targeting the Notch pathway with drugs such as the γ-secretase inhibitors may be an effective therapeutic strategy that improves outcomes in this disease.     

青蒿琥酯对生存素在乳腺癌细胞株MDA-MB-231表达的影响

目的 探讨青蒿琥酯对生存素(survivin)在乳腺癌细胞株MDA-MB-231中表达的影响.方法 以不同浓度(0、25、50 μg/mL)的青蒿琥酯处理MDA-MB-231细胞,分别于药物处理后24、48和72 h收集细胞及培养上清液,用RT-PCR检测不同组别、不同时间点的细胞中survivin的基因表达情况,酶联免疫吸附试验(ELISA)检测各组、各时间点培养上清液中survivin的蛋白质表达水平.结果 PCR结果和ELISA结果均显示,随着药物浓度的增加和处理时间的延长,survivin基因水平和蛋白质水平的表达也逐渐降低,同一时间点各组间survivin的表达量进行单因素方差分析,差异有统计学意义(P＜0.05);对照组(0 μg/mL)在24 h和48 h survivin的表达量变化不大,经t检验分析,差异无统计学意义(P＞0.05),而各浓度经药物处理48 h后survivin的表达量明显低于24 h的表达,差异有统计学意义(P＜0.05).结论 青蒿琥酯可通过抑制survivin的表达促进乳腺癌MDA-MB-231细胞凋亡.     

Antisense oligonucleotide inhibition of serine/threonine kinases: an innovative approach to cancer treatment.

The identification of genes that confer a growth advantage on neoplastic cells and the understanding of the genetic mechanism(s) responsible for their activation have made possible a direct genetic approach to cancer treatment using nucleic acid therapeutics. Moreover, the ability to block the expression of individual genes that promote carcinogenesis provides a powerful tool to explore the molecular basis of normal growth regulation, as well as the opportunity for therapeutic intervention. One technique for turning off a single activated gene is the use of antisense oligodeoxynucleotides and their analogs for inhibition of gene expression. The serine/threonine kinases are involved in mediating intracellular responses to external signals, such as growth factors, hormones, and neurotransmitters, and are involved in cell proliferation and oncogenesis. Described herein are recent studies supporting the potential use of oligonucleotides targeting these kinases as chemotherapeutic agents for cancer treatment. The serine/threonine kinases included here are protein kinase A, protein kinase C, and c-raf-1 kinase.     

Antisense oligonucleotide therapy in cancer

The sequencing of the human genome has highlighted some of the genes that are of importance in disease states. This has provided opportunities for the development of new therapeutics to target a wide range of human diseases. These new drugs are intended to be highly specific; antisense oligonucleotides (ONs) are one such class of new drugs. ONs are short pieces of DNA which hybridize to a specific target mRNA blocking its translation to protein, thereby inhibiting the action of the gene. Several genes known to be of importance in the regulation of apoptosis, cell growth, metastasis and angiogenesis provide a tantalizing prospect for the development of anticancer agents. The phosphorothioate antisense ONs are the current choice for antisense therapy. This article reviews the current strategies for antisense targets in cancer therapy.     

Antisense approaches in prostate cancer

Patients with hormone refractory prostate cancer have limited treatment options and new therapies are urgently needed. Advances in the understanding of the molecular mechanisms implicated in prostate cancer progression have identified many potential therapeutic gene targets that are involved in apoptosis, growth factors, cell signalling and the androgen receptor (AR). Antisense oligonucleotides are short sequences of synthetic modified DNA that are designed to be complimentary to a selected gene's mRNA and thereby specifically inhibit expression of that gene. The antisense approach continues to hold promise as a therapeutic modality to target genes involved in cancer progression, especially those in which the gene products are not amenable to small molecule inhibition or antibodies. The current status and future direction of a number of antisense oligonucleotides targeting several genes, including BCL-2, BCL-XL, clusterin, the inhibitors of apoptosis (IAP) family, MDM2, protein kinase C-alpha, c-raf, insulin-like growth factor binding proteins and the AR, that have potential clinical use in prostate cancer are reviewed.     

塞来昔布对胃癌细胞凋亡及survivin mRNA表达的影响

目的:探讨塞来昔布(celecoxib)对胃癌细胞株MGC803凋亡的影响,为寻求新的胃癌治疗策略提供理论依据.方法:MGC803细胞经塞来昔布处理后,用AO/EB荧光染色检测细胞凋亡率;RT-PCR检测凋亡相关基因survivinmRNA的表达.结果:荧光染色法显示塞来昔布可诱导MGC803细胞凋亡,并呈时间、剂量依赖性;RT-PCR检测发现塞来昔布可抑制凋亡相关基因survivinmRNA的表达.结论:塞采昔布诱导MGC803凋亡可能与survivinmRNA表达下调有关.