促红细胞生成素及受体在肿瘤中表达与作用研究近况

<正>促红细胞生成素(Erythropoietin,EPO)是肾脏分泌的一种糖蛋白激素,其主要功能是通过作用于骨髓造血细胞,促进红系祖细胞增殖、分化,抑制造血组织中红系祖细胞的凋亡来增进红细胞的生成。该作用是通过其特异的膜受体     

促红细胞生成素及受体神经保护作用的研究进展

促红细胞生成素（EPO）是刺激红细胞造血的生长因子和细胞因子。最近几年,有报道显示EPO在神经系统中有重要的非造血功能,对神经系统的发生、维持、保护和修复有极为关键的作用。大量实验研究显示EPO及其受体在神经系统中有表达,在细胞培养和神经系统紊乱的动物模型中EPO发挥着显著的神经保护作用。本文对EPO的分子机制、神经营养和神经保护特性进行综述。     

促红细胞生成素受体在骨髓增生异常综合征中的表达及意义

<正>促红细胞生成素(erythropoietin,EPO)与红细胞表面EPO受体(EPOR)结合后,EPOR形成二聚体,再通过JAK/STAT和RAS/MAP激酶等信号传导途径调节红系的增生和分化。E-POR不仅存在于幼红细胞,在其他细胞中也发现了EPOR[1]。近年来对急性白血病及实体肿瘤患者中EPOR表达的研究     

重组人促红细胞生成素对卵巢癌细胞EPOR表达及肿瘤增殖的影响

目的通过检测卵巢癌细胞中的促红细胞生成素受体（EPOR）表达，以及r—HuEPO对卵巢癌细胞增值的影响，探讨r—HuEPO在癌性贫血治疗中的意义。方法RT—PCR方法检测人卵巢癌细胞株HO-8910EPOR mRNA的表达及卵巢癌细胞增值影响。结果卵巢癌细胞表面有EPOR的表达。r—HuEPO干预后卵巢癌细胞增值受到抑制（P〈0．01）。结论EPOR在卵巢癌细胞株HO8910有表达，r—HuEPO可抑制卵巢癌细胞的增值发生，提示r—HuEPO可用于卵巢癌伴发的贫血的治疗。     

持续型红细胞生成素受体激活剂研究进展

红细胞生成素(EPO)是机体在生理条件下以及失血后调控红细胞生成的主要生长刺激因子,是目前治疗由肾功能衰竭、慢性感染、获得性免疫缺陷综合征、肿瘤或其他原因引起的贫血病的特效临床药物之一。但由于其在人体内的血浆半衰期较短,需要频繁注射,给患者带来很大痛苦。因此,开发长效EPO一直是该领域的研究热点。持续型EPO受体激活剂(CERA)是新出现的一种第三代红细胞生成刺激剂(ESA)。与常规EPO不同,它具备较长的体内半衰期,可减少注射次数。本文阐述了CERA的由来,分子结构和生化特征,不良反应及其作为新型兴奋剂使用所引起的国际关注。     

人促红细胞生成素在CHO细胞上的表达

为了获得人促红细胞生成素(EPO)的高效表达,以EPO gDNA 为基础构建了两个真核表达载体pDE、pCE,将它们分别经脂质体转染CHO-dhfr-细胞,其48h瞬时表达量分别为27.5ng/ml与88.90ng/ml.然后用氨甲喋呤(MTX)对转染细胞进行加压并挑选细胞克隆,共获得3株高效表达EPO的工程细胞株A,B,C,其中A来自质粒pCE,B和C来自pDE,在2×10-6mol/L的MTX的压力下,它们48h的最高表达水平分别为A:8.7μg/ml,B:10.76μg/ml,C:16.44μg/ml.经网织红细胞法测得它们均具有体内生物活性.     

促红细胞生成素拟肽研究进展

促红细胞生成素(Epo)是一种主要由肾脏合成并且分泌的活性糖蛋白,可刺激骨髓造血,主要用于治疗慢性肾功能衰竭导致的贫血性疾病,Epo口服不吸收,需静脉注射给药。由于其在人体内的生物半衰期较短,需要频繁注射,给患者在使用过程中带来很多不便并造成一定的经济负担。因此,开发疗效好、不良反应小且持续时间长的Epo一直是研究热点,目前市场上出现了多种新型的促红细胞生成素类药物,其中Epo拟肽的相关研究一直备受人们的关注,本文综述了近年来有关Epo拟肽类药物的研究情况。     

急性白血病患者促红细胞生成素与血红蛋白的相关性研究

目的　探讨急性白血病血清促红细胞生成素 (sEP0 )与血红蛋白 (Hb)的关系。方法　采用放射免疫分析法测定sEP0 ,采用常规血细胞计数仪测定Hb。结果　sEP0与Hb之间在ALL治疗前、4周缓解组均呈负相关关系 (分别为 r =-0 4 2 7,-0 5 5 7,P均 <0 0 5 ) ;AML治疗前呈负相关关系 (r =-0 6 5 1,P<0 0 5 ) ,缓解后无相关性 (r =-0 6 30 ,P >0 0 5 )。结论　急性白血病患者sEP0与Hb在急性白血病治疗前呈负相关关系 ,缓解后无相关性。因此 ,白血病贫血不是由于EP0的生成不足导致的 ,用rHuEP0治疗效果可能有限。     

促红细胞生成素及其受体神经营养和神经保护作用研究进展

促红细胞生成素(erythropoietin,EPO)是在红细胞发生过程中起重要作用的红细胞生成生长因子,可促进造血祖细胞增殖、分化.促红细胞生成素受体(EPOR)是造血细胞因子受体超家族中的成员之一,EPO通过激活特异性EPO[t并启动相应的信号传导途径而发挥生物学作用.     

促红细胞生成素及其受体神经营养和神经保护作用研究进展

促红细胞生成素(erythropoietin,EPO)是在红细胞发生过程中起重要作用的红细胞生成生长因子,可促进造血祖细胞增殖、分化.促红细胞生成素受体(EPOR)是造血细胞因子受体超家族中的成员之一,EPO通过激活特异性EPO[t并启动相应的信号传导途径而发挥生物学作用.     

Differential pharmacokinetic analysis of in vivo erythropoietin receptor interaction with erythropoietin and continuous erythropoietin receptor activator in sheep

The two erythropoiesis stimulating agents (ESAs), short acting recombinant human erythropoietin (EPO) and long acting continuous erythropoietin receptor activator (CERA), have been hypothesized to share an in vivo elimination pathway that involves binding to erythropoietin receptor (EPOR) and subsequent internalization. A physiologically based recirculation model and a pharmacokinetic tracer interaction methodology (TIM) were used to compare the in vivo interaction kinetics with EPOR between the two ESAs in adult sheep. Animals treated with EPO experienced a greater EPOR up-regulation than those treated with CERA, as evidenced by an eightfold-higher initial EPOR normalized production rate constant, k(syn) /R(0) , versus a twofold-larger EPOR degradation rate constant, k(deg) . In agreement with in vitro studies, EPO had a lower in vivo equilibrium dissociation constant from EPOR than CERA (K(D) = 6 versus 88.4 pmol/l, respectively, p < 0.01). The internalization and/or degradation of the EPO-EPOR complex was faster than that of the CERA-EPOR complex (k(int) = 24 versus 2.41 h(-1) , respectively, p < 0.01). The adopted model enables a mechanism-based explanation for CERA's slower elimination and greater erythropoietic activity in vivo. As predicted by the model, the slower elimination of CERA is due to: (1) less EPOR up-regulation induced by CERA administration; (2) slower binding of CERA to EPOR; and (3) reduced internalization and/or degradation rate of surface-bound CERA. Slower CERA/EPOR complex elimination explains the greater in vivo erythropoiesis reported for CERA, despite its lower affinity to EPOR. A sensitivity analysis showed that the model parameters were reliably estimated using the TIM methodology.     

人体尿液中新型促红细胞生成受体激动剂的检测

In the present study, isoelectronic focusing with different pH gradients ( pH 3−5, 2−6) or migrating distances (8.5, 12 and 17 cm) and SDS-PAGE was used to separate continuous erythropoietin receptor activator (CERA), recombinant human erythropoietin (rhEPO), darbepoitin and endogenous EPO spiked in human urine with 37 ℃ overnight incubation.  Double blotting and chemiluminescent visualization were used to detect the IEF and SDS-PAGE profiles.  The bands of CERA profile were detected and well separated from the endogenous EPO and the other two EPO preparations with both SDS-PAGE and the IEF method using a gradient pH 3−5 and a migrating distance of 17 cm, and a significant particular band of CERA profile was found in the IEF result.  These preliminary results indicated that the methods were reliable and reproducible for detecting CERA, and could be used as a routine procedure for anti-doping analysis.     

重组人红细胞生成素对骨髓间充质干细胞红细胞生成素受体的上调作用

目的研究重组人红细胞生成素(rhEpo)处理骨髓间充质干细胞(MSCs)后对Epo受体(EpoR)的影响。方法含rhEpo0,5及10kU.L-1的培养基培养MSCs24,48及72h后,MTT法检测细胞增殖;6d后,免疫荧光染色检测EpoR阳性的细胞百分率。rhEpo预处理24h,再缺氧处理48h,Hoechst染色,通过形态变化检测细胞凋亡率;rhEpo预处理6d,再缺氧处理48h,Western蛋白印迹法检测EpoR,磷酸化Janus激酶2(p-Jak2),磷酸化转导及转录活化蛋白(p-Stat5)及缺氧诱导因子-1a(Hif-1a)蛋白表达。结果MTT结果显示,rhEpo处理的MSCs增殖能力增强;免疫荧光结果显示,随rhEpo浓度的增加,EpoR阳性细胞数增加;对照组,rhEpo5及10kU.L-1组EpoR阳性细胞百分率分别为(8.3±4.2)%,(24.7±8.1)%和(30.8±10.5)%。rhEpo预处理能增强MSCs抗缺氧凋亡的能力,缺氧处理后,对照组、rhEpo5及10kU.L-1组细胞核固缩率分别为(42.2±8.7)%,(21.9±8.0)%和(20.1±7.9)%。Western蛋白印迹结果显示,rhEpo预处理及预处理后行低氧培养的MSCs,随rhEpo浓度的增加,EpoR及下游抗细胞凋亡蛋白p-Jak2,p-Stat5和Hif-1a蛋白表达增加。结论rhEpo可以促进MSCEpoR的表达,并增加EpoR下游抗细胞凋亡蛋白的表达。     

Pharmacokinetic tracer kinetics analysis of changes in erythropoietin receptor population in phlebotomy-induced anemia and bone marrow ablation

OBJECTIVES: The objective was to study in vivo erythropoietin (Epo) progenitor cell surface receptors (EpoR) in the bone marrow (BM) after phlebotomy and bone marrow ablation. METHODS: Serial tracer interaction method experiments were conducted in adult sheep at baseline and after phlebotomy (PH) and ablation (AB). PH was done 10 days after phlebotomy (to 3-4 g/dl Hb), and the AB was done 8 days after a 3-day oral treatment with bulsulfan (11 mg/kg/day). RESULTS: Bone marrow ablation changed the elimination from non-linear to linear, consistent with an abolition of the non-linear elimination via BM EpoRs. The phlebotomy increased the linear clearance of the ablated elimination pathway (from 63.6+/-12 to 126+/-64 ml/h/kg), consistent with an up-regulation of the erythroid progenitor BM-based EpoR pool, but did not change the clearance of the non-ablated elimination pathway (p>0.05). The EpoR pool size remaining after BM ablation was 7.4+/-2.7% of the pre-ablation pool. CONCLUSIONS: Erythropoietin elimination via EpoR in the bone marrow was non-linear and increased following phlebotomy-induced anemia. This is consistent with an up-regulation of the erythropoietic EpoR pool in BM. Assuming that the elimination of Epo after BM ablation was via non-hematopoietic EpoR, then this post-ablation EpoR population was not significantly up-regulated by the phlebotomy.     

Pharmacodynamic analysis of stress erythropoiesis: change in erythropoietin receptor pool size following double phlebotomies in sheep

A feedback receptor regulation model was incorporated into a pharmacodynamic model to describe the stimulation of hemoglobin (Hb) production by endogenous erythropoietin (EPO). The model considers the dynamic changes that take place in the EPO receptor (EPOR) pool under phlebotomy-induced anemia. Using a (125)I-rhEPO tracer the EPO clearance changes are evaluated longitudinally prior to and following phlebotomy-induced anemia indirectly to evaluate changes in the EPOR pool size, which has been shown to be linearly related to the clearance. The proposed model simultaneously captures the general behavior of temporal changes in Hb relative to EPO plasma clearance in five lambs (r = 0.95), while accounting for the confounding variables of phlebotomy and changes in the blood volume in the growing animals. The results indicate that under anemia the EPOR pool size is up-regulated by a factor of nearly two over baseline and that the lowest and highest EPOR pool sizes differ by a factor of approximately four. The kinetic model developed and the data-driven mechanism proposed serves as a starting point for developing an optimal EPO dosing algorithm for the treatment of neonatal anemia.     

99mTc‐labeled rHuEpo for imaging of the erythropoietin receptor in tumors

To analyze erythropoietin receptor (EpoR) status in tumors, recombinant human erythropoietin (rHuEpo) was labeled with ^99mTc by ^99mTc‐centered 1‐pot synthesis, resulting in high radiochemical purity, stability, and biological activity. Both in vitro cell culture experiments and biodistribution studies of normal rats demonstrated successful EpoR targeting. The biodistribution of labeled rHuEpo in a NCI‐H1975 xenograft model showed tumor accumulation (tumor‐to‐muscle ratio, 4.27 ± 1.77), confirming the expression of active EpoR in tumors. Thus, as a novel single positron emission computerized tomography tracer for the imaging of EpoR expression in vivo, ^99mTc‐rHuEpo is effective for exploring the role of EpoR in cancer growth, metastasis and angiogenesis.     

Mitoxantrone in the treatment of acute leukemia

Summary Forty-six patients with acute leukemia were treated with mitoxantrone as a single agent. Twenty-nine patients had relapsed and/or refractory acute leukemia. Seventeen patients with acute non-lymphatic leukemia had received no prior treatment. Twelve mg/m² of mitoxantrone was given intravenous on five consecutive days. Treatment related side effects included bone marrow suppression, mucositis, alopecia, nausea, vomiting and infection. Cardiotoxicity was documented in 7 patients. This study reconfirms that mitoxantrone is an active agent in acute leukemia with complete response documented in 10 of 29 patients with relapsed and/or refractory acute leukemia (34% response rate, 95% confidence limits 18–53%) and complete response documented in 11 of 17 patients (65% response rate, 95% confidence limits 38–87%) with previously untreated acute non-lymphatic leukemia.