细胞自噬与肿瘤耐药

细胞自噬是一种细胞自我降解的过程,在适应代谢应激、保持基因组完整性及维持内环境稳定方面发挥重要作用. 在肿瘤治疗中,凋亡耐受是产生肿瘤耐药的重要机制. 细胞自噬可防止抗肿瘤药诱导的凋亡,促进肿瘤耐药. 然而,自噬性细胞死亡可能是凋亡耐受肿瘤细胞的一种死亡方式. 因此,细胞自噬对肿瘤细胞的耐药性有双重影响. 本文综述了细胞自噬的分子机制、细胞自噬与凋亡的关系、细胞自噬与肿瘤耐药以及治疗的主要研究进展.     

综述: 细胞自噬在肿瘤发生发展中的作用

自噬是保守的细胞防御机制,又是程序性细胞死亡机制．在多种人类肿瘤中存在细胞自噬活性改变．自噬活性降低促进肿瘤的发生和进展．综述了近年来细胞自噬在肿瘤中的研究进展,从基因组不稳定性、炎-癌链转化和演进、致瘤微生 物感染和宿主免疫应答、细胞凋亡途径与自噬的交叉调节等角度探讨自噬抑制肿瘤的机理,以及细胞自噬在肿瘤治疗中的作用．     

Post-transcriptional Gene Regulation by MicroRNA-194 Promotes Neuroendocrine Transdifferentiation in Prostate Cancer

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AMPK Promotes SPOP-Mediated NANOG Degradation to Regulate Prostate Cancer Cell Stemness

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前列腺癌的靶向治疗研究现状与展望

前列腺癌难以根治,研究雄激素非依赖型前列腺癌的靶向治疗具有实际的临床意义,涉及抗体靶向治疗、靶向抗前列腺癌药物研制、细胞生长信号转导通路抑制、微小RNA应用等多方面,而靶向清除肿瘤干细胞则是根治前列腺癌的有效策略。     

垂体瘤转化基因1(PTTG1)的表达变化对人前列腺癌细胞LNCaP生长增殖的影响

垂体肿瘤转化基因1(PTTG1)具有促进肿瘤生长和转移的作用.通过上调或下调基因表达的策略,观察PTTG1基因对人前列腺癌细胞株LNCaP细胞生长增殖的影响.利用PCR技术分离出PTTG1全长cDNA,分别正向和反向插入真核表达载体pIRES2-EGFP,重组载体分别命名为正义PTTG1-S/pIRES2-EGFP(即pI-P-S)和反义PTTG1-AS/pIRES2-EGFP(即pI-P-AS),将这两种重组载体稳定转染LNCaP细胞,通过流式细胞仪和MTT法分别检测了细胞周期和细胞增殖的情况.转染正义PTTG1后处于S期和G2期的细胞明显增加,细胞生长增殖能力增强;相反,转染反义PTTG1后处于S期和G2期细胞明显减少,细胞生长增殖能力减弱(P<0.05).结果表明,PTTG1能明显改变人前列腺癌细胞株LNCaP的细胞周期和细胞生长增殖能力,它的异常表达可能参与前列腺癌细胞生长增殖过程.     

前列腺癌鼠模型

前列腺癌鼠模型是研究前列腺癌的重要工具,目前常见以下4类：自发和诱发鼠模型,异种移植鼠模型,转基因鼠模型和基因敲除鼠模型。简要综述了前列腺癌鼠模型的研究进展。     

Overexpression of FGF9 in Prostate Epithelial Cells Augments Reactive Stroma Formation and Promotes Prostate Cancer Progression

Bone metastasis is the major cause of morbidity and mortality of prostate cancer (PCa). Fibroblast growth factor 9 (FGF9) has been reported to promote PCa bone metastasis. However, the mechanism by which overexpression of FGF9 promotes PCa progression and metastasis is still unknown. Herein, we report that transgenic mice forced to express FGF9 in prostate epithelial cells (F9TG) developed high grade prostatic intraepithelial neoplasia (PIN) in an expression level- and time-dependent manner. Moreover, FGF9/TRAMP bigenic mice (F9TRAMP) grew advanced PCa earlier and had higher frequencies of metastasis than TRAMP littermates. We observed tumor microenvironmental changes including hypercellularity and hyperproliferation in the stromal compartment of F9TG and F9TRAMP mice. Expression of TGFβ1, a key signaling molecule overexpressed in reactive stroma, was increased in F9TG and F9TRAMP prostates. Both in vivo and in vitro data indicated that FGF9 promoted TGFβ1 expression via increasing cJun-mediated signaling. Moreover, in silico analyses showed that the expression level of FGF9 was positively associated with expression of TGFβ1 and its downstream signaling molecules in human prostate cancers. Collectively, our data demonstrated that overexpressing FGF9 in PCa cells augmented the formation of reactive stroma and promoted PCa initiation and progression.     

敲减BLM解旋酶表达增强前列腺癌PC3细胞对丝裂霉素C的敏感性

丝裂霉素C是一种广谱抗肿瘤抗生素,对多种癌症有抗癌作用,其作用原理可使细胞的DNA发生链间交联,引起DNA双链断裂,阻碍DNA的复制,从而抑制肿瘤细胞分裂。临床上主要用于胃癌、肠癌、肝癌及胰腺癌等消化道癌方面的治疗。本文研究丝裂霉素C对转染人BLM解旋酶基因（shRNA载体）前后前列腺癌PC3细胞活性的影响。使用前期成功构建的干扰载体转染PC3细胞,在转染48 h后加药,通过荧光定量PCR、MTT法、Transwell小室实验、细胞划痕实验、流式细胞术,分别检测加药12、24、36 h BLM基因的表达量、PC3细胞增殖能力、侵袭能力、迁移能力及凋亡情况的变化。结果显示,敲减BLM基因表达后的PC3细胞相对于正常PC3细胞其增殖能力、侵袭能力和迁移能力能显著被丝裂霉素C抑制,且丝裂霉素C能显著促进其细胞的凋亡,说明BLM基因低表达的前列腺癌细胞对丝裂霉素C更敏感。研究结果为丝裂霉素C在前列腺癌的临床治疗上奠定了理论基础。     

综述: 微环境调控肿瘤代谢的研究

20世纪20年代,奥托·瓦博格首次发现肿瘤细胞在正常氧的情况下优先利用糖酵解的现象．近一个世纪以来,细胞代谢在肿瘤发生发展中的作用引起了广泛的关注．其基本机制是肿瘤细胞在营养匮乏的环境中通过劫持、重塑不同的细胞代谢途径,包括合成和分解途径,从而为其生存和增殖提供生物大分子原料;而这些代谢途径改变和代谢物的变化通过转录、表观、翻译和翻译后修饰等不同机制来调控细胞的生命活动, 从而在肿瘤发生发展中起着至关重要的作用．因此,代谢异常是肿瘤的十大特征之一．近年来,随着对癌基因和抑癌基因的突变以及各类生长因子和下游信号通路的深入研究,特别是近十年对肿瘤细胞所处的微环境在肿瘤发生发展中的关键作用不断阐明,人们逐步认识到肿瘤细胞和其所处微环境的相互作用对肿瘤代谢的重塑产生重要的影响,因此揭示微环境对肿瘤细胞代谢的调控机制,将为肿瘤的诊断和治疗提供新的靶点和合理化治疗方案,从而提高肿瘤病人的生存率及其生活质量．     

双向凝胶电泳技术在前列腺癌研究中的应用

双向凝胶电泳是目前蛋白质组学研究最常用的技术之一,近年来,在前列腺癌的研究中也有很多实际应用,取得了一些成果。本文按照双向电泳的样品来源,分类综述了目前基于双向电泳的蛋白质组学技术在寻找前列腺癌肿瘤标记物、药物靶标和阐明其发生发展机理研究中的应用。     

Dihydroceramide accumulation mediates cytotoxic autophagy of cancer cells via autolysosome destabilization

Autophagy is considered primarily a cell survival process, although it can also lead to cell death. However, the factors that dictate the shift between these 2 opposite outcomes remain largely unknown. In this work, we used Δ⁹-tetrahydrocannabinol (THC, the main active component of marijuana, a compound that triggers autophagy-mediated cancer cell death) and nutrient deprivation (an autophagic stimulus that triggers cytoprotective autophagy) to investigate the precise molecular mechanisms responsible for the activation of cytotoxic autophagy in cancer cells. By using a wide array of experimental approaches we show that THC (but not nutrient deprivation) increases the dihydroceramide:ceramide ratio in the endoplasmic reticulum of glioma cells, and this alteration is directed to autophagosomes and autolysosomes to promote lysosomal membrane permeabilization, cathepsin release and the subsequent activation of apoptotic cell death. These findings pave the way to clarify the regulatory mechanisms that determine the selective activation of autophagy-mediated cancer cell death.     

TrkB Promotes Breast Cancer Metastasis via Suppression of Runx3 and Keap1 Expression

In metastatic breast cancer, the acquisition of malignant traits has been associated with the increased rate of cell growth and division, mobility, resistance to chemotherapy, and invasiveness. While screening for the key regulators of cancer metastasis, we observed that neurotrophin receptor TrkB is frequently overexpressed in breast cancer patients and breast cancer cell lines. Additionally, we demonstrate that TrkB expression and clinical breast tumor pathological phenotypes show significant correlation. Moreover, TrkB expression was significantly upregulated in basal-like, claudin-low, and metaplastic breast cancers from a published microarray database and in patients with triple-negative breast cancer, which is associated with a higher risk of invasive recurrence. Interestingly, we identified a new TrkB-regulated functional network that is important for the tumorigenicity and metastasis of breast cancer. We demonstrated that TrkB plays a key role in regulation of the tumor suppressors Runx3 and Keap1. A markedly increased expression of Runx3 and Keap1 was observed upon knockdown of TrkB, treatment with a TrkB inhibitor, and in TrkB kinase dead mutants. Additionally, the inhibition of PI3K/AKT activation significantly induced Runx3 and Keap1 expression. Furthermore, we showed that TrkB enhances metastatic potential and induces proliferation. These observations suggest that TrkB plays a key role in tumorigenicity and metastasis of breast cancer cells through suppression of Runx3 or Keap1 and that it is a promising target for future intervention strategies for preventing tumor metastasis and cancer chemoprevention.     

Screening and Characterization of a Novel RNA Aptamer That Specifically Binds to Human Prostatic Acid Phosphatase and Human Prostate Cancer Cells

Prostatic acid phosphatase (PAP) expression increases proportionally with prostate cancer progression, making it useful in prognosticating intermediate to high-risk prostate cancers. A novel ligand that can specifically bind to PAP would be very helpful for guiding prostate cancer therapy. RNA aptamers bind to target molecules with high specificity and have key advantages such as low immunogenicity and easy synthesis. Here, human PAP-specific aptamers were screened from a 2′-fluoropyrimidine (FY)-modified RNA library by SELEX. The candidate aptamer families were identified within six rounds followed by analysis of their sequences and PAP-specific binding. A gel shift assay was used to identify PAP binding aptamers and the 6N aptamer specifically bound to PAP with a Kd value of 118 nM. RT-PCR and fluorescence labeling analyses revealed that the 6N aptamer bound to PAP-positive mammalian cells, such as PC-3 and LNCaP. IMR-90 negative control cells did not bind the 6N aptamer. Systematic minimization analyses revealed that 50 nucleotide sequences and their two hairpin structures in the 6N 2′-FY RNA aptamer were equally important for PAP binding. Renewed interest in PAP combined with the versatility of RNA aptamers, including conjugation of anti-cancer drugs and nano-imaging probes, could open up a new route for early theragnosis of prostate cancer.     

PC-１基因表达增强C4-2B前列腺癌细胞生存

建立稳定表达外源PC-１基因的人前列腺癌骨转移C4-2B细胞模型,初步探讨PC- １基因表达对前列腺癌发展的影响.通过脂质体介导的方法,将融合PC-１基因的真核表达载体pcDNA3.1PC-１稳定转染C4-2B细胞,Western 印迹和RT-PCR技术,分别从蛋白水平和RNA水平确定外源PC-１基因表达. MTT和软琼脂集落形成能力等一系列方法,研究PC-１基因的功能,RT-PCR和实时定量PCR检测前列腺癌发生发展相关基因表达的变化. 结果表明,PC-１基因的高表达能够诱导雄激素受体（AR）调控基因和一系列重要的信号通路成员基因PSA、PSMA、NKX31、Jagged1、EphA3、SGEF和 NOTCH3等表达发生变化. 实验结果初步证明,PC-１基因表达在晚期前列腺癌中,以及在雄激素非依赖的转变中可以发挥作用,PC-１基因表达可调控一些重要信号通路.对PC-１基因功能深入研究将有可能为发现新的前列腺癌的诊断治疗分子靶标提供线索.     

GATA1通过上调NANOG促进胰腺癌肿瘤干细胞形成

目的:探究GATA1在胰腺癌肿瘤干细胞形成中的功能和作用机制。方法:通过流式细胞术检测GATA1对胰腺癌肿瘤干细胞形成的影响;通过实时荧光定量PCR和Western印迹筛选和验证GATA1下游的干性基因;通过双萤光素酶报告基因实验和染色质免疫共沉淀明确GATA1的调控机制。结果:GATA1过表达细胞株中肿瘤干细胞含量增加;GATA1上调NANOG的mRNA和蛋白表达水平;GATA1可以增强NANOG启动子的活性;GATA1结合在NANOG启动子-527^-524bp处的GATA序列。结论:GATA1可以通过结合在NANOG启动子上激活其转录,促进胰腺癌肿瘤干细胞的形成。     

血管生成素与前列腺癌

血管生成素（angiogenin,ANG）属脊椎动物特异的核糖核酸酶A超家族第5个成员,是一种分泌型核糖核酸酶,在人类前列腺癌高表达.ANG在前列腺癌的上皮细胞和内皮细胞转位入核,通过刺激rRNA生物合成而介导肿瘤血管新生、癌细胞存活及增殖,从而促进前列腺癌的进程.ANG刺激rRNA合成不仅为前列腺内皮细胞发生癌变所必需,也是前列腺癌细胞不依赖雄激素生长所必需.动物实验证明,各种针对ANG的拮抗剂,包括抑制其核转位、功能和活性的抑制剂均可抑制前列腺癌.现已明确ANG的作用不依赖雄激素,从而为ANG作为去势（即睾丸切除）抗性前列腺癌（castration resistant prostate cancer）的治疗靶标提供了坚实的理论基础.     

鸟氨酸脱羧酶基因反义RNA对前列腺癌细胞生长的抑制作用

为研究鸟氨酸脱羧酶 (ODC)基因反义RNA对前列腺癌细胞的生长抑制作用 ,将表达ODC第 3外显子反义RNA的重组腺病毒rAd ODC Ex3as分别感染前列腺癌细胞株PC 3和LNCap .通过MTT法观察其对前列腺癌细胞增殖的影响 ,并确定不同细胞合适的感染滴度 ,再采用Western印迹和流式细胞术检测rAd ODC Ex3as对细胞中ODC表达的抑制作用、对细胞周期和凋亡的影响以及与CDK抑制物p2 1的关系 .实验显示 ,rAd ODC Ex3as分别以 5 0MOI、2 5MOI感染PC 3和LNCap细胞可明显抑制其生长增殖 ,而不引起细胞毒性作用 ;其对两种细胞中ODC表达的抑制作用分别为4 5 %和 5 9% .流式细胞DNA含量分析证实 ,rAd ODC Ex3as可引起PC 3和LNCap细胞周期G1期阻滞 ,但并未引起凋亡 .通过Western印迹发现 ,细胞中ODC表达的降低可诱导p2 1蛋白的过表达 .结果表明 ,rAd ODC Ex3as在体外能有效地干扰ODC基因的表达 ,并通过诱导p2 1的过表达使其细胞周期停于G1期 ,从而抑制前列腺癌细胞PC 3和LNCap的增殖 ,为其进一步基因治疗的研究打下基础 .     

BRD4 Promotes DNA Repair and Mediates the Formation of TMPRSS2-ERG Gene Rearrangements in Prostate Cancer

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