TRAIL及其在白血病治疗中的研究进展

肿瘤坏死因子相关凋亡诱导配体(TRAIL)是近几年研究较热的抗肿瘤新型生物制剂,通过其死亡受体诱导肿瘤细胞凋亡,而对正常细胞无毒性,且与化疗药物具有协同性,但也存在抵抗机制.该文就TRAIL的生物学特点及其受体、TRAIL诱导肿瘤细胞凋亡的机制以及TRAIL在白血病治疗中的进展作一综述.     

蒽环类药物对白血病细胞的细胞毒作用与活性氧的关系研究进展

蒽环类抗生素用于白血病的治疗已30余年历史,已成为化疗不可缺少的药物之一。近年来研究显示,蒽环类抗生素对白血病细胞的细胞毒作用包括凋亡。而活性氧(reactive oxygen species,ROS)是细胞增殖、分化、成熟及凋亡过程中的重要介质;同时它与细胞耐药、心脏毒性有关。研究其作用机制将更好地了解白血病化疗的机制,更好地指导临床治疗。文章简述了蒽环类药物的作用机制及ROS与蒽环类药物细胞毒作用的关系,以期为临床研究提供参考。     

核心蛋白聚糖与细胞凋亡的关系

核心蛋白聚糖是蛋白聚糖家族中的一员,富含亮氨酸.广泛存在于细胞外基质中,它可以调节多种细胞以及细胞因子的相互作用,生物功能十分活跃.前几年对核心蛋白聚糖功能的研究主要集中在其与转化生长因子之间的关系卜,而近几年的研究表明,核心蛋广1聚糖在调节细胞凋亡中也起重要作用,它可以抑制肾小管上皮细胞的凋亡,促进肿瘤细胞的凋亡,发挥抗肾纤维化和抗肿瘤的作用.除了以上作用外,由于核心蛋门聚糖由人体自身产生,其免疫原性低,可能在疾病防治中具有广阔的应用前景.     

多源耐药基因表达水平的检测在儿童白血病中的临床意义

白血病是我国儿童恶性肿瘤中最多见的类型，尽管新的治疗手段有所应用，但化疗仍然是白血病的主要治疗方法，而影响化疗药物疗效的重要因之一是多源耐药（multidrug re－sistance）基因的高水平表达，其结果可以产生对多种结构、作用机制完全不同的药物同时耐药，因此对联合应用的化疗方案造成不良影响。多源耐药基因编码一个分子量为 170 kb的细胞膜糖蛋白（P一糖蛋白），在正常细胞中它是一个ATP依赖性的胞内脂质物质输出泵，起到转运胞内代谢产物的作用。抗肿瘤药物中：烷化剂类、植物碱类、抗肿瘤抗生素及激素类都是脂质（或亲脂疏水）性物质，多源耐药基因的蛋白质产物就是通过将这些药物泵出细胞而降低了药物在细胞内的浓度而使肿瘤细胞产生耐药性。我们应用逆转录PCR结合同位素定量分析，对 32例儿童白血病患者的多源耐药基因表达水平进行了研究。复发病人 MDR的表达里高水平（0． 474土 0． 087，P＜0． of），而初发病人未接受化疗者，MDR的表达则呈低水平（0． 157士0． 148），PMO． 05），缓解期病人的 MDR表达水平介于两者之间，该研究为探讨多源耐药基因表达水平与临床化疗之间的相关性及逆转克服多源耐药性药物的应用，提供了一定的理论依据。     

化疗对儿童白血病实质脏器的损伤及防治

近半个世纪来,随着化疗药物的不断问世,化学疗法在恶性肿瘤综合治疗中的地位愈来愈重要.特别是儿童白血病化疗的合理应用,使肿瘤治疗的疗效有较大幅度的提高.然而目前临床所应用的化疗药物均缺乏特异性,即在杀伤肿瘤细胞的同时亦会不同程度地损害机体的正常组织细胞,产生许多不良反应,如肝脏毒性、心脏毒性、肾毒性等.     

miRNA与肿瘤耐药性及逆转耐药策略北大核心CSCD

恶性肿瘤是严重影响人类健康的疾病,化学药物治疗是其主要的治疗方式之一。肿瘤细胞通过多种机制对化疗药物产生耐药是引起治疗失败的重要原因,微小RNA（mi—croRNA,miRNA）的转录后调节是肿瘤产生耐药性的机制之一,是目前肿瘤治疗研究的热点领域。研究表明miR—NA除了可以作为肿瘤预测和诊断的生物学指标,更重要的是它的异常表达与肿瘤的耐药性有特征性联系,一些特定miRNA的抑制和重新表达可以提高抗肿瘤药物的疗效,本文简要综述miRNA与肿瘤耐药性的研究进展。     

铁剥夺诱导HL-60细胞凋亡及对化疗药物诱导HL-60细胞凋亡的影响

目的 探讨铁剥夺对HL－60细胞凋亡及对化疗药物诱导HL－60细胞凋亡的影响。方法 HL－60细胞与不同浓度的铁螯合剂－去铁胺（DFO）、DFO加化疗药物、化疗药物、DFO加化疗药物及三氯化铁、三氯化铁共同培养6h、12h、24h、48h。通过测定细胞活力,观察细胞形态学变化,应用流式细胞仪检测和DNA凝胶电泳等方法观察细胞凋亡;通过亲和免疫组化方法检测c-myc基因表达,从而确定DFO及DFO与化疗药物联合应用对HL－60细胞的作用。结果 DFO单用可降低HL－60细胞活力、抑制HL－60细胞增殖、诱导HL－60凋亡,并可使c-myc基因表达增加,其作用强度随培养时间延长及DFO浓度增加而增加。DFO与化疗药物联合时,可增加化疗药物诱导HL－60细胞凋亡的作用。该作用可被等摩尔的三氯化铁抵消。结论 铁剥夺可影响HL－60细胞DNA的合成,诱导其凋亡,并提高HL－60细胞对化疗药物的敏感性。因此,铁剥夺可作为临床上白血病治疗或辅助治疗的方法之一,不适当补铁或升高血红蛋白将影响化疗疗效。     

动脉化疗栓塞术对小儿肾母细胞瘤细胞凋亡和增殖的影响

目的探讨动脉化疗栓塞术(TACE)对肾母细胞瘤(WT)细胞凋亡指数(AI)和细胞增殖指数(PI)的影响,并评价其在临床治疗中的地位。方法将24例肾母细胞瘤患儿按临床分期、病理分型进行配对设计研究,设动脉化疗栓塞组12例,全身化疗组12例,采用TUNEL法和免疫组织化学超敏二步法测定标本的细胞凋亡指数和细胞增殖指数。结果动脉化疗栓塞组AI高于全身化疗组(P<0.05),PI低于全身化疗组(P<0.05),AI与PI成负相关(P<0.05),动脉化疗栓塞组术后瘤体缩小,坏死程度高于全身化疗组(P<0.05),而骨髓抑制少(P<0.05)。结论与全身化疗组相对比,术前采用动脉化疗栓塞法能更有效地诱导肿瘤细胞凋亡,抑制肿瘤细胞增殖,促使肿瘤缩小、坏死,有利于手术根治,取得更好的疗效,提高生存率。     

RNA聚合酶Ⅰ转录抑制剂治疗白血病及肿瘤性疾病的研究进展

<正>近10余年来,靶向治疗因其基于特定的作用靶点而发挥抗肿瘤作用,由于具有特异性强、对正常组织毒副作用小,而一直成为白血病及肿瘤领域的研究热点,也成为化疗的重要辅助手段。目前靶向药物作用靶点主要为细胞表面分子、细胞内激酶、抗凋亡分子及通过表观遗传学机制为靶点,虽然临床取得一定疗效,但仍未明显延长患者的生存期。目前亟待发现新的靶向药物,提高白血病及肿瘤患者的     

白血病的多药耐药机制及临床意义

近年来随着白血病完全缓解率和治愈率的提高，肿瘤细胞对抗肿瘤药物的耐药性也越来越多，而且它是白血病化疗失败的一个重要因素。什么叫多药耐药（MultidrugRe－sistance，MDR）？它是指肿瘤细胞接触了一种药物后，不但对该药产生抗药性，而且对其它结构和作用机制不同的药物也产生抗药作用。白血病MDR机制的阐明及耐药逆转剂的应用，必然极大地改善肿瘤病人化疗的预后水平。现将近年来关于MDR产生机制的研究进展综述如下。一、rndrl基因及Pgn的作用机制：在MDR机制中mdrl基因和卜糖蛋白（Pglycoprotein，Pgp）起了很重要的作用。P…     

TRAIL/Apo2L ligands induce apoptosis in malignant rhabdoid tumor cell lines

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL/Apo2L) is a potent inducer of apoptosis in various cancer cells, whereas normal cells are not sensitive to TRAIL-mediated apoptosis. Four TRAIL/Apo2L receptors (DR4, DR5, DcR1, and DcR2) have been identified. DR4 and DR5 have a death domain, whereas DcR1 and DcR2 are called decoy receptors because of their incomplete or lack of a death domain. Malignant rhabdoid tumor (MRT) is an aggressive neoplasm showing a poor prognosis because of its resistance to chemotherapeutic agents. In this study, we examined whether TRAIL could induce apoptotic cell death in MRT cell lines. We found that although half of the MRT cell lines examined were sensitive to TRAIL/Apo2L, Western blot analysis revealed that the expression of DcR2 was low in TRAIL-sensitive MRT cells. We examined the effect of doxorubicin on the expression levels of TRAIL receptors and its enhancement on the susceptibility of MRT cell lines to TRAIL. Western blot and flow cytometric analyses revealed that doxorubicin significantly increased the expression of DR5, and somewhat up-regulated the expression of DR4 and DcR2. Moreover, doxorubicin, NF-kappaB inhibitor (SN50), and PI3-kinase/Akt inhibitor (wortmannin, LY294002) enhanced the susceptibility of MRT cell lines to TRAIL/Apo2L-induced apoptosis. These results suggest that TRAIL/Apo2L may provide the basis for clinical trials of TRAIL-based treatment to improve the outcome of MRT patients.     

Caspase-8和DR5在TRAIL诱导神经母细胞瘤细胞凋亡中的作用

目的：肿瘤坏死因子相关凋亡诱导配体(TRAIL)能诱导多种肿瘤细胞凋亡而对正常细胞无诱导凋亡作用。大多数神经母细胞瘤细胞株对TRAIL的诱导凋亡作用耐受与其Caspase8表达缺失有关,也与细胞表面TRAIL受体的表达和分布有关。该文主要探讨Caspase8及TRAIL受体DR5的表达在TRAIL诱导神经母细胞瘤细胞株SKNDZ凋亡中的作用及其发生机制。方法：应用RTPCR方法检测IFNγ作用前后SKNDZ细胞Caspase8的表达;应用WesternBlot方法检测化疗药作用前后SKNDZ细胞DR5的表达;应用四甲基偶氮唑蓝(MTT)比色法及流式细胞仪(FCM)检测TRAIL、IFNγ+TRAIL、化疗药+TRAIL及化疗药+IFNγ+TRAIL对SKNDZ细胞生长及凋亡的影响。结果：SKNDZ细胞不表达Caspase8,IFNγ作用后的SKNDZ细胞Caspase8表达明显增加。对照组未检测到DR5蛋白表达,而阿霉素和依托泊苷处理后检测到DR5蛋白表达。表达Caspase8的SKNDZ细胞对TRAIL的诱导凋亡作用仍不敏感,而同时表达Caspase8和DR5的SKNDZ细胞对TRAIL的诱导凋亡作用敏感。阿霉素/依托泊苷+IFNγ+TRAIL组早期凋亡率为:(17.9±3.6)%、(14.8±3.3)%,与IFNγ+TRAIL组(3.9±1.2)%比较,差异有显著性(F=26.233,P<0.01)。结论：同时表达Caspase8和DR5的SKNDZ细胞恢复了对TRAIL的敏感性,Caspase8和DR5在TRAIL诱导SKNDZ细胞凋亡中起着十分关键的作用。     

A new hamster fibrosarcoma model for in vitro/in vivo evaluation of cancer chemotherapeutic agents.

A hamster fetal cell clone has been developed for in vitro chemotherapeutic studies as well as in an in vivo fibrosarcoma model system. Highly reproducible quantitative in vitro chemotherapeutic data can be obtained with this cell line within 5 days, and as few as 10(2) cells produce rapidly growing fibrosarcomas when injected subcutaneously into adult hamsters. We found using these cells in vitro that 1-beta-D-arabinofuranosylcytosine (ara-C) can antagonize the effect of 5-azacytidine (aza-C) if given simultaneously or if aza-C treatment is preceded by a 2-hr exposure to ara-c. Using the same cell line as in vivo model for chemotherapy it was also shown that ara-C and cyclocytidine significantly inhibited tumor growth. This hamster cell line may be quite useful as an in vitro/in vivo model system for the study of cancer chemotherapeutic agents.     

A new hamster fibrosarcoma model for in vitro/in vivo evaluation of cancer chemotherapeutic agents

A hamster fetal cell clone has been developed for in vitro chemotherapeutic studies as well as in an in vivo fibrosarcoma model system. Highly reproducible quantitative in vitro chemotherapeutic data can be obtained with this cell line within 5 days, and as few as 10² cells produce rapidly growing fibrosarcomas when injected subcutaneously into adult hamsters. We found using these cells in vitro that 1-β-D-arabinofuranosylcytosine (ara-C) can antagonize the effect of 5-azacytidine (aza-C) if given simultaneously or if aza-C treatment is preceded by a 2-hr exposure to ara-c. Using the same cell line as in vivo model for chemotherapy it was also shown that ara-C and cyclocytidine significantly inhibited tumor growth. This hamster cell line may be quite useful as an in vitro/in vivo model system for the study of cancer chemotherapeutic agents.     

Platinum agents in the treatment of osteosarcoma: efficacy of cisplatin vs. carboplatin in human osteosarcoma cell lines

BACKGROUND: Cisplatin (cDDP), when used either alone or, more often, in combination with other agents, especially adriamycin, achieves a high response rate in osteosarcoma. Its use, however, is limited by severe nephro- and neuro-toxicity. Second generation platinum compounds, most notably carboplatin (CBDCA), have been developed in order to attempt to reduce these dose-limiting toxicities, and thus improve the therapeutic ratio. Studies evaluating the role of combination CT containing CBDCA vs. cDDP have demonstrated differing results depending on the tumor type tested and its role in the treatment of osteosarcoma has yet to be clarified. PROCEDURE: In this study, we compared the in vitro anti-tumor activity of cDDP and CBDCA in a panel of three human osteosarcoma cell lines (HOS, MG63, and U2OS). RESULTS: cDDP and CBDCA (0-20 micromol) showed marked variation in cytotoxicity among the three cell lines. EC(50) values for CBDCA in HOS and MG63 cells were approximately two-fold higher than for cDDP and the ratio of AUC(CBDCA) to AUC(cDDP) varied from 1.8 in the HOS cell line to 2.3 in the MG63 cell line. Exposure of MG63 and HOS cells to either cDDP or CBDCA (1.67 and 13.5 micromol) caused a G2/M cell cycle arrest by 24 hr. Also evident was a sub G1 peak indicative of cell death by apoptosis. U2OS cells were relatively resistant to the cytotoxic effects of both drugs, although a cell cycle arrest in response to DNA damage was observed. This suggests that unlike MG63 and HOS cells, U2OS cells have either a more efficient repair pathway for platinum-induced DNA damage or are able to evade apoptosis. Examination of apoptotic events and cellular recovery demonstrated that both an 8-16-fold higher concentration and longer treatment period for CBDCA compared with cDDP was required to produce equivalent cell death and a loss of the ability of single cell clones to form colonies in both the HOS and MG63, but not the U2OS cell line. CONCLUSIONS: Our findings suggest that CBDCA at a two- to four-fold higher concentration than cDDP has potential therapeutic activity in platinum sensitive osteosarcomas, particularly when cDDP cytotoxicity compromises therapeutic efficacy.     

Effects of 17-allylamino-17-demethoxygeldanamycin (17-AAG) on pediatric acute lymphoblastic leukemia (ALL) with respect to Bcr-Abl status and imatinib mesylate sensitivity

As more and more effective targeted therapeutics have been developed to treat adults with cancer, it is of critical importance to devise appropriate in vitro experimental models to study their use in pediatric patients. Acute lymphoblastic leukemia (ALL) with Bcr-Abl translocation is one of the most difficult to treat and deadly diseases in children. The targeted kinase inhibitor imatinib mesylate has been shown to induce an initial response but resistance often develops. Recently, the geldanamycin family of antibiotics has been found to induce apoptosis in many malignant cells, including adult CML and AML. We describe experiments in which 17-allylamino-17-demethoxygeldanamycin (17-AAG) was evaluated in the context of Bcr-Abl and resistance to imatinib mesylate. Pediatric ALL cell lines with varying Bcr-Abl status and imatinib mesylate sensitivity were generated and their growth inhibition by 17-AAG was studied in vitro. Western blots were used to follow the changes in proteins that correlate with cell survival. Results show that apoptosis was induced in all lines with an increased 50% inhibitory concentration (IC50) for Bcr-Abl positive but imatinib mesylate-resistant cells. Addition of 17-AAG greatly increased imatinib sensitivity in vitro. A decrease in p53, survivin, Her2/neu, and WT1 was seen in cells that expressed these proteins. With some notable exceptions, when combined with 17-AAG, the IC50 of most of the common chemotherapeutic agents decreased. We describe an experimental approach to investigate the complex interaction between Bcr-Abl status, imatinib mesylate sensitivity, and 17-AAG in pediatric ALL. Information from such an approach will provide means to devise combined treatment approaches and to follow their effectiveness in vitro.     

Retinoic acid-induced apoptosis of the CHP134 neuroblastoma cell line is associated with nuclear accumulation of p53 and is rescued by the GDNF/Ret signal

BACKGROUND: Neuroblastoma (NBL) is one of the most common solid malignancies in childhood and is derived from the sympathetic precursor cells. Although p53, a tumor suppressor, has been reported to be rarely mutated in NBLs, it is sequestered abnormally in the cytoplasm of the NBL cell. The mechanism and functional role of the abnormal intracellular localization of p53 remain unclear. PROCEDURE: Here, we established an in vitro system of apoptosis model using a NBL cell line CHP134 which also showed a cytoplasmic sequestration of p53. The treatment of the cells with 1 or 5 microM all-trans retinoic acid (RA) induced moderate neurite outgrowth followed by massive death of CHP134 cells by days 5 to 6. RESULTS: TUNEL staining showed that the cell death was due to apoptosis. Immunofluorescent stain demonstrated that p53 was strongly positive in the nucleus on day 5, which was accompanied with induction of p21WAF1. In addition, expression of caspase-3 was also increased during the cell death. Intriguingly, the RA treatment induced expression of Ret tyrosine kinase receptor in CHP134 cells. CONCLUSIONS: The addition of ligands, glial cell line-derived neurotrophic factor (GDNF) and neurturin (NTN), inhibited apoptosis as well as nuclear accumulation of p53 in the cell. The present results suggest that the RA-induced apoptosis of NBL cells is associated with activation of both the caspase cascade and the p53-mediated pathway with its nuclear translocation. The neurotrophic signal through the GDNF-Ret system may prevent the neuronal cell death.