老年人急性髓细胞白血病多药耐药蛋白过度表达的实验与临床研究

 目的　初步分析老年急性髓细胞白血病（AML）患者P-糖蛋白（P-gp）、多药耐药相关蛋白（MRP）、肺耐药蛋白（LRP）的表达及其在预后中的意义。方法　流式细胞仪活细胞直接或间接免疫荧光法检测12例初治老年AML（M2a 4例,其中1例由MDS转化而来;M4a 2例;M5a 5例;M6 1例）患者骨髓白血病细胞P-gp、MRP、LRP表达情况。分析这些多药耐药蛋白表达与预后的关系。结果　P-gp、MRP、LRP的表达率分别为58.33 %、8.33 %、50 %;P-gp(+)、MRP(+)0,P-gp(+)、LRP(+)33.33 %,MRP(+)、LRP(+)0,P-gp(+)、MRP(+)、LRP(+)8.33 %,P-gp(-)、MRP(-)、LRP(-)33.33 %,其中P-gp、LRP单独和二者共表达频率较高。P-gp(+)者的完全缓解（CR）率与2年总生存率（OS）均显著低于P-gp(-)者（P＝0.01）,LRP(+)者的CR率与2年OS亦均低于LRP(-)者。结论　老年AML患者 P-gp、LRP单独及二者共表达频率均较高。P-gp、LRP过度表达是老年AML患者的不良预后因素。     

Activity and expression of the multidrug resistance proteins P-glycoprotein, MRP1, MRP2, MRP3 and MRP5 in de novo and relapsed acute myeloid leukemia.

The multidrug resistance proteins (MRPs) MRP1, MRP2, MRP3, MRP5 and P-glycoprotein (P-gp) act in concert with each other to give a net resultant pump function in acute myeloid leukemia (AML). The aim of the present study was to analyze the activity of these proteins, which might be upregulated at relapse as compared with de novo AML due to clonal selection. The mRNA expression and activity of P-gp and the MRPs were determined with RT-PCR and flow cytometry, in conjunction with phenotype, as measured with the monoclonal antibodies CD34, CD38 and CD33, in 30 paired samples of de novo and relapsed AML. P-gp and MRP activity varied strongly between the cases (rhodamine 123 efflux-blocking by PSC833: 5.4+/-7.7, and carboxyfluorescein efflux-blocking by MK-571: 4.3+/-6.7, n = 60). P-gp and MRP activity were increased in 23% and 40% of the relapse samples, and decreased in 30% and 20% of the relapse samples, respectively (as defined by a difference of >2 x standard deviation of the assays). Up- or downregulation of mRNA expression was observed for MDR1 (40%), MRP1 (20%), MRP2 (15%), MRP3 (30%), and MRP5 (5%). Phenotyping demonstrated a more mature phenotype in 23% of the relapsed AML cases, and a more immature phenotype in 23% of the relapses, which was independent of the karyotypic changes that were observed in 50% of the studied cases. P-gp and MRP activity correlated with the phenotypic changes, with higher P-gp and MRP activities in less mature cells (r = -0.66, P < 0.001 and r = -0.31, P = 0.02, n = 58). In conclusion, this study shows that P-gp and MRP activity are not consistently upregulated in relapsed AML. However, P-gp and MRP activities were correlated with the maturation stage as defined by immune phenotype, which was observed to be different in 46% of the relapses.     

Distinct expression profiles of MSI2 and NUMB genes in myelodysplastic syndromes and acute myeloid leukemia patients

Recent studies have indicated the Musashi2/NUMB pathway as the key regulator of differentiation in chronic myeloid leukemia; however, a comparison of both gene expressions has not yet been made in myelodysplastic syndrome (MDS) and in acute myeloid leukemia (AML). We herein, demonstrate a statistically significant down-modulation of NUMB expression level in high-risk MDS and AML, compared with control individuals. MSI2 expression was significantly reduced in low and high-risk MDS compared with normal control samples. NUMB expression was significantly lower than that of MSI2 in both MDS and AML patient samples, but no differences in the expression levels for either gene were observed in healthy bone marrow cells. Finally, NUMB expression was significantly up-regulated during differentiation of normal and low-risk MDS CD34(+) cells through the erythroid lineage. Taken together, results suggest the involvement of NUMB in MDS erythropoiesis; its down-modulation may have a role in MDS progression.     

Multiple gene expression analysis reveals distinct differences between G2 and G3 stage breast cancers, and correlations of PKC eta with MDR1, MRP and LRP gene expression.

A possible link between protein kinase C (PKC) and P-glycoprotein (P-gp)-mediated-multidrug resistance (MDR) was assumed from studies on MDR cell lines selected in vitro. The functional relevance of PKC for the MDR phenotype remains unclear, and the involvement of a particular PKC isozyme in clinically occurring drug resistance is not known. Recently, we have demonstrated significant correlations between the expression levels of the PKC eta isozyme and the MDR1 or MRP (multidrug resistance-associated protein) genes in blasts from patients with acute myelogenous leukaemia (AML) and in ascites cell aspirates from ovarian cancer patients. To extend these findings to further types of human tumours we analysed specimens from 64 patients with primary breast cancer for their individual expression levels of several MDR-associated genes (MDR1, MRP, LRP (lung cancer resistance-related protein), topoisomerase (Topo) II alpha/IIbeta, cyclin A and the PKC isozyme genes (alpha, beta1, beta2, eta, theta, and mu) by a cDNA-PCR approach. We found significantly enhanced mean values for MRP, LRP and PKC eta gene expression, but significantly decreased Topo II alpha and cyclin A gene expression levels in G2 tumours compared with G3. Remarkably, significant positive correlations between the MDR1, MRP or LRP gene expression levels and PKC eta were determined: MDR1/PKC eta (rs = +0.6451, P < 0.0001) n = 62; MRP/PKC eta (rs = +0.5454, P < 0.0001) n = 63; LRP/PKC eta (rs = +0.5436, P < 0.0001) n = 62; MRP/LRP (rs = +0.7703, P < 0.0001) and n = 62, MDR1/MRP (rs = +0.5042, P < 0.0001) n = 62. Our findings point to the occurrence of a multifactorial MDR in the clinics and to PKC eta as a possible key regulatory factor for up-regulation of a series of MDR-associated genes in different types of tumours.     

Expression of Lung Resistance Protein and Correlation with Other Drug Resistance Proteins and Outcome in Myelodysplastic Syndromes

The major vault lung resistance protein LRP is a cytoplasmic protein involved in drug resistance, especially in acute myeloid leukemia. We looked for LRP overexpression, using immunocytochemistry with LRP 56 monoclonal antibody, on marrow slides from 41 cases of myelodysplastic syndromes (MDS). LRP overexpression (LRP+) was defined by expression of LRP 56 in at least 20% of marrow blasts. LRP overexpression was seen in 19 (46%) cases. Concordant results between LRP overexpression and P-glycoprotein (PGP) expression were seen in 66% of the cases (p = 0.03), and discordant results (LRP+ and PGP-, or LRP-and PGP+) in 33% of the cases. No correlation was seen between LRP overexpression and FAB type, karyotype, CD34, p53 expression and bc12 overexpression in blasts. Furthermore, in the 18 cases treated with anthracycline-AraC intensive chemotherapy and the 7 cases treated with low dose AraC, the response rate was not significantly different in LRP+ and LRP-patients. Survival was also similar in LRP+ and LRP—patients. In conclusion, LRP overexpression is probably more frequent in MDS than in de novo AML and, as in AML, is only partially correlated with PGP expression. In our experience, however, LRP was not a prognostic factor for response to chemotherapy and survival in MDS.     

骨髓增生异常综合征中CD34+细胞CXCR4的表达及其与细胞迁移的相关性

  目的  探讨不同危险度骨髓增生异常综合征（myelodysplasticsymdromes,MDS）中骨髓CD34+细胞CXCR4的表达情况及其与细胞迁移率的相关性。   方法  收集40例骨髓增生异常综合征患者的骨髓标本,根据IPSS积分系统进行危险度分组。低危组20例:IPSS积分0~1.5分;高危组20例:IPSS积分≥1.5分;同时采集10例健康者的骨髓标本作为对照。分离纯化骨髓CD34+细胞,通过流式细胞术检测CXCR4膜蛋白的表达;研究SDF-1α趋化作用下CD34+细胞的迁移率及CD34+细胞对骨髓基质细胞的迁移率。   结果  高危组MDS患者CD34+细胞CXCR4的表达率明显高于低危组和正常对照组（P < 0.000 1）;低危组和正常对照组之间CXCR4的表达率无显著性差异（P>0.05）。高危组CD34+细胞对SDF-1α及骨髓基质细胞的迁移率显著高于低危组及正常组（均P < 0.000 1）,且其对骨髓基质细胞的迁移率与CXCR4的表达呈正相关（P=0.000 1）。   结论  高危组MDS患者CD34+细胞CXCR4的表达量及其对骨髓基质细胞的迁移率均明显高于低危组患者,且其迁移率随CXCR4表达量的增加而升高,不同风险组的MDS患者存在SDF-1及其受体CXCR4表达和功能上的差异,SDF-1及其受体CXCR4在MDS发病中具有重要作用。      

Fas ligand expression in the bone marrow in myelodysplastic syndromes correlates with FAB subtype and anemia, and predicts survival.

Increased apoptosis in the bone marrow (BM) may contribute to the cytopenias that occur in myelodysplastic syndromes (MDS). The Fas receptor, Fas ligand (FasL) pathway is a major mechanism of apoptosis. Since hematopoietic progenitors can express the Fas receptor, they may be susceptible to apoptosis induced by FasL-expressing cells. We examined FasL expression in the BM of patients with MDS (n = 50), de novo acute myeloid leukemia (AML; n = 10), AML following prior MDS (n = 6), and normal controls (n = 6). Compared to controls, FasL expression was increased in MDS, and was highest in AML. In MDS, FasL expression was seen in myeloid blasts, erythroblasts, maturing myeloid cells, megakaryocytes and dysplastic cells, whereas in AML, intense expression was seen in the blasts. FasL expression correlated with the FAB subtype groups of MDS, and also correlated directly with the percentage of abnormal metaphases on cytogenetic analysis. The FasL expressed in MDS BM inhibited the growth of clonogenic hematopoietic progenitors. This inhibition could be blocked by a soluble recombinant FasFc protein. In MDS, FasL expression in the initial diagnostic BM was higher in patients who were more anemic, correlated directly with red cell transfusion requirements over the subsequent course of the disease, and was predictive of survival. These studies indicate that FasL expression in MDS is of prognostic significance, and suggest that pharmacological blockade of the Fas-FasL pathway may be of clinical benefit.     

非霍奇金淋巴瘤多药耐药的实验研究

目的 探讨初发非霍奇金淋巴瘤(NHL)mdrl mRNA及多药耐药蛋白P糖蛋白(P-gp)、肺耐药蛋白(LRP)和多药耐药相关蛋白(MRP)的表达频率及临床意义.方法 采用逆转录多聚酶链反应(RT-PCR)半定量方法检测41例初治NHL患者淋巴结活组织中瘤细胞mdrl mRNA的表达,采用流式细胞仪免疫荧光法检测P-gP、LRP、MRP的表达,以13例反应性增生淋巴结患者作为对照组.并分析多药耐药蛋白表达与NHL临床特征的关系.结果 41例NHL患者中,11例mdrl mRNA表达阳性,8例P-gP表达阳性,7例MRP表达阳性,15例LRP表达阳性.NHL组与对照组比较,MRP阳性率差异无统计学意义(P=0.887),LRP阳性率明显增高(P=0.047).NHL患者淋巴结组织P-gP、MRP、LRP表达两两之间均不存在相关关系,P-gP表达与mdrl mRNA表达正相关(r=0.396,P=0.01).P-gP表达与临床分期、LDH水平有关(均P<0.05),而与恶性分级无关.MRP表达与临床分期、恶性分级、血清乳酸脱氢酶(LDH)水平均无关(均P>0.05),而LRP表达与三者均有关(均P<0.05).P-gP和LRP表达阳性患者的完全缓解(CR)率分别为37.5%和53.3%,低于阴性表达者(均P<0.05),化疗疗效较差,而MRP表达与化疗疗效无关.结论 P-gP、LRP可能是NHL原发耐药的主要因素,影响NHL患者的化疗疗效,而MBP与NHL原发耐药无关,不影响NHL患者的化疗疗效.     

鼻咽癌组织中P-gp、MRP和LRP的表达及其临床意义

目的探讨多药耐药基因蛋白(P-gp)、多药耐药相关蛋白(MRP)和肺耐药相关蛋白(LRP)在鼻咽癌组织中的表达情况及其临床意义。方法应用单克隆抗体多药耐药相关蛋白(P-gp),多药耐药基因蛋白(MRP),肺耐药相关蛋白(LRP),对54例鼻咽癌初诊患者的肿瘤组织进行免疫组化检测。结果3项多药耐药指标在54例患者中有不同程度表达。P-gp、MRP、LRP的表达与鼻咽癌病理类型、临床分期及有无淋巴结转移不相关;P-gp表达与MRP、LRP表达不相关,MRP与LRP表达间呈正相关。结论联合检测LP-gp、MRP、LRP在鼻咽癌组织中的表达,对鼻咽癌化疗药物的选择及预后的判断都有重要的参考价值。     

Telomerase activity and telomere length in acute and chronic leukemia, pre- and post-ex vivo culture

We studied telomerase regulation and telomere length in hematopoietic progenitor cells from peripheral blood and bone marrow from patients with acute and chronic leukemia and myeloproliferative diseases. CD34+ cells from a total of 93 patients with either acute myeloid leukemia (AML; n = 25), chronic myeloid leukemia (CML; n = 21), chronic lymphocytic leukemia (CLL; n = 18), polycythemia vera (PV; n = 16), or myelodysplastic syndromes (MDS; n = 13) were analyzed before and in 19 patients after ex vivo expansion in the presence of multiple cytokines (kit ligand, interleukin-3, interleukin-6, and granulocyte colony-stimulating factor plus erythropoietin). Compared with hematopoietic progenitor cells from normal donors (n = 108), telomerase activity (TA) was increased 2- to 5-fold in chronic phase (CP)-CML, CLL, PV, and MDS. In AML, accelerated phase (AP) and blastic phase (BP)-CML, basal TA was 10- to 50-fold higher than normal. TA of CP-CML CD34+ cells was up-regulated within 72 h of ex vivo culture, peaked after 1 week, and decreased below detection after 2 weeks. In contrast, TA in AP/BP-CML and AML CD34+ cells was down-regulated after 1 week of culture and decreased further thereafter. The expansion potential of CD34+ cells from patients with leukemia was considerably decreased compared with CD34+ cells from normal donors. The average expansion of cells from leukemic individuals was 6.5-, 2.3-, 0.6-, and 0.2-fold in weeks 1, 2, 3, and 4, respectively, whereas expansion of normal cells was 5- to 15-fold higher. In serial expansion culture, a median telomeric loss of 0.7 kbp was observed during 3-4 weeks of expansion. Our results demonstrate that up-regulation of telomerase is similar in CD34+ cells from CP-CML, CLL, PV, and MDS patients and in normal hematopoietic cells during the first week of culture, whereas in AML and AP/BP-CML, telomerase is high at baseline and down-regulated during expansion culture. High levels of telomerase in leukemic progenitors at baseline may be a feature of both the malignant phenotype and rapid cycling. Telomerase down-regulation during culture of leukemic cells may be due to the decreased expansion potential or repression of normal hematopoiesis, or in AML it may be due to the partial differentiation of AML cells, shown previously to be associated with loss of TA. Telomere shortening during ex vivo expansion correlated with low levels of TA, particularly in chronic leukemic and MDS progenitors where telomerase was insufficient to protect against telomere bp loss during intense proliferation.     

Detection of molecular targets on the surface of CD34+/CD38-- stem cells in various myeloid malignancies

Recent data suggest that myeloid neoplasms are organized hierarchically in terms of self-renewal and maturation of early progenitor cells, similar to normal myelopoiesis. In acute myeloid leukemia (AML), the NOD/SCID mouse-repopulating leukemic stem cells usually co-express CD123 with CD34, but lack CD38. So far, however, little is known about expression of other markers and targets on these progenitors. In the present study, expression of target antigens on CD34+/CD38- cells was analysed by multi-color flow cytometry in patients with AML (n = 18), myelodysplastic syndromes (MDS, n = 6), chronic myeloid leukemia (CML, n = 8) and systemic mastocytosis (SM, n = 9). The IL-3Ralpha chain (CD123) was found to be expressed on CD34+/CD38- cells in a majority of the patients in all disease categories. Independent of the type of disease, the vast majority of these stem cells co-expressed aminopeptidase-N (CD13) and CD44 in all patients. By contrast, the CD34+/CD38- progenitor cells expressed variable amounts of the target receptor CD33, c-kit (CD117) and AC133 (CD133). In conclusion, neoplastic stem cells in various myeloid neoplasms appear to express a similar phenotype including target antigens such as CD13, CD33 and CD44. Since many of these targets are not expressed on all stem cells in all patients, the elimination of the entire clone may require combinations of targeted antibodies or use of additional drugs.     

Expression of multidrug resistance proteins,P-gp,MRP1 and LRP,in soft tissue sarcomas analysed according to their histological type and grade

The biological behaviour of different histological types and grades of soft tissue sarcomas (STS) varies. This might result in a differing sensitivity to cytotoxic drugs. Cross-resistance to functionally and structurally distinct natural-product drugs, known as multidrug resistance (MDR), is associated with the overexpression of P-glycoprotein (P-gp), multidrug resistance-associated protein 1 (MRP1) and lung resistance-related protein (LRP). The purpose of this study was to evaluate the expression of P-gp, MRP1 and LRP in STS according to their histological type and grade. In 141 chemotherapy-naive STS patients, the expression of the three MDR proteins was detected by immunohistochemistry. Nine histological types were documented. These were 19% grade 1, 34% grade 2 and 47% grade 3 tumours. Expression of P-gp and LRP was observed more frequently than the expression of MRP1 (P<0.0001). P-gp expression was most pronounced in malignant fibrous histiocytoma (MFH), but was low in leiomyosarcomas. MRP1 was expressed in most malignant peripheral nerve sheath tumours (MPNST). LRP was strongly expressed in MFH and unspecified sarcomas, but was low in liposarcomas. MRP1 and LRP expression was significantly more common in grades 2 and 3 compared with grade 1 tumours. P-gp expression was correlated with MRP1, especially in grade 3 STS. In conclusion, P-gp, MRP1 and LRP are expressed in the majority of STS, but this expression varies according to the histological type. MRP1 and LRP, but not P-gp expression, were found to be correlated to tumour grade. MDR might contribute to the observed differences in clinical behaviour within the heterogeneous group of STS.     

The expression and significance of P-glycoprotein,lung resistance protein and multidrug resistance-associated protein in gastric cancer

Background

To detect the expression of multidrug resistance molecules P-glycoprotein (P-gp), Lung resistnce protein (LRP) and Multidrug resistance-associated protein (MRP) and analyze the relationship between them and the clinico-pathological features.

Methods

The expressions of P-gp, LRP and MRP in formalin-fixed paraffin-embedded tissue sections from 59 gastric cancer patients were determined by a labbelled Streptavidin-Peroxidase (SP) immunohistochemical technique, and the results were analyzed in correlation with clinicopathological data. None of these patients received chemotherapy prior to surgery.

Results

The positive rates of P-gp, LRP, MRP were 86.4%, 84.7% and 27.1%, respectively. The difference between the positive rate of P-gp and MRP was significant statistically, as well as the difference between the expression of MRP and LRP. No significant difference was observed between P-gp and LRP, but the positively correlation between the expression of P-gp and LRP had been found. No significant correlation between the expression of P-gp, LRP, MRP and the grade of differentiation were observed. The expression of P-gp was correlated with clinical stages positively (r = 0.742), but the difference with the expression of P-gp in different stages was not significant.

Conclusion

The expressions of P-gp, LRP and MRP in patients with gastric cancer without prior chemotherapy are high, indicating that innate drug resistance may exist in gastric cancer.     

Reduced effect of gemtuzumab ozogamicin (CMA-676) on P-glycoprotein and/or CD34-positive leukemia cells and its restoration by multidrug resistance modifiers.

Gemtuzumab ozogamicin (CMA-676), a calicheamicin-conjugated humanized anti-CD33 mouse monoclonal antibody, has recently been introduced clinically as a promising drug for the treatment of patients with acute myeloid leukemia (AML), more than 90% of which express CD33 antigen. However, our recent study suggested that CMA-676 was excreted by a multi- drug-resistance (MDR) mechanism in P-glycoprotein (P-gp)-expressing leukemia cell lines. We analyzed the in vitro effects of CMA-676 on leukemia cells from 27 AML patients in relation to the amount of P-gp, MDR-associated protein 1 (MRP1), CD33 and CD34, using a multi-laser-equipped flow cytometer. The cytocidal effect of CMA-676, estimated by the amount of hypodiploid portion on cell cycle, was inversely related to the amount of P-gp estimated by MRK16 monoclonal antibody (P = 0.004), and to the P-gp function assessed by intracellular rhodamine-123 accumulation in the presence of PSC833 or MS209 as a MDR modifier (P = 0.0004 and P = 0.002, respectively). In addition, these MDR modifiers reversed CMA-676 resistance in P-gp-expressing CD33(+) leukemia cells (P = 0.001 with PSC833 and P = 0.0007 with MS209). In CD33(+) AML cells from 13 patients, CMA-676 was less effective on CD33(+)CD34(+) than CD33(+)CD34(-) cells (P = 0.002). PSC833 partially restored the effect of CMA-676 in CD33(+)CD34(+) cells. These results suggest that the combined use of CMA-676 and a MDR modifier will be more effective on CD33(+) AML with P-gp-related MDR.     

Drug resistance-associated markers P-glycoprotein, multidrug resistance-associated protein 1, multidrug resistance-associated protein 2, and lung resistance protein as prognostic factors in ovarian carcinoma.

Intrinsic and/or acquired resistance to chemotherapy is the major obstacle to overcome in the treatment of patients with ovarian carcinoma. The aim of the present study was to investigate the prognostic value of drug resistance-associated proteins P-glycoprotein (P-gp), multidrug resistance-associated protein 1 (MRP1), canalicular multispecific organic anion transporter (c-MOAT/MRP2), and lung resistance protein (LRP) in ovarian carcinoma. Expression of P-gp, MRP1, MRP2, and LRP was determined by immunohistochemistry of frozen tissue sections of 115 ovarian carcinoma patients and related to clinicopathological factors, response to chemotherapy, and progression-free survival. P-gp expression was observed in 20 of 115 (17%), MRP1 in 51 (44%), MRP2 in 19 (16%), and LRP in 85 (74%) tumors. Expression of MRP1 was related to MRP2 (P<0.0001) and P-gp (P<0.001) expression, whereas LRP expression was more frequently observed in patients with early stage (P<0.01), lower grade (P<0.05), and smaller residual tumor (P<0.05). Early stage (P<0.001), smaller residual tumor (P<0.001), and lower differentiation grade (P<0.05) were related to longer (progression-free) survival. P-gp, MRP1, MRP2, and LRP expression were neither related to response to first-line chemotherapy in 59 evaluable patients nor to progression-free survival in all patients. On multivariate analysis, only stage and residual tumor were independent prognostic factors for survival. In conclusion, in ovarian carcinoma, MRP1 expression is associated with MRP2 and P-gp expression, whereas LRP expression is associated with favorable clinicopathological characteristics. Assessment of P-gp, MRP1, MRP2, or LRP does not allow prediction of response to chemotherapy or survival in ovarian carcinoma.     

急性白血病细胞P-gp LRP的表达及其临床意义

目的：研究急性白血痛细胞P-糖蛋白（P—gp）、肺耐药蛋白（LRP）的表达情况，观察其表达率与临床症状及化疗缓解率的关系。方法：利用P—gp、LRP单克隆抗体，采用流式细胞技术分别测定15例正常对照和79例急性白血病（AL）患者P-gp、LRP的表达率，分析两种蛋白表达的临床意义。结果：初治急性淋巴细胞白血病（ALL）组P—gp、LRP的表达率均高于初治急性髓细胞白血病（AML）组（P〈0．01），复发／难治ALL组P—gp的表达率与复发／难治AML组相比无显著性差异（P〉0．05），而LRP的表达率较复发／难治AML组的表达率高（P〈0．01）。复发／难治组P—gp、LRP的表达率均高于相应的初治组（P〈0．05）。急性白血病患者P—gp、LRP的表达之间无相关性（L=0．0746，P〉0．05）。急性白血病细胞P—gp^＋／LRP^＋组缓解率低于P—gp^＋／LRP^-、P—gp^-／LRP^＋组（P〈0．05），并明显低于P—gp^-／LRP^-组（P〈0．01）。结论：复发／难治组P—gp、LRP的表达率高于初治组，而两者的表达率无相关性。P—gp、LRP表达阳性的患者缓解率低，且易出现髓外浸润。同时检测P—gp、LRP的表达较单独检测一种蛋白更具有临床意义。     

Clinical significance of CD95, Bcl-2 and Bax expression and CD95 function in adult de novo acute myeloid leukemia in context of P-glycoprotein function, maturation stage, and cytogenetics.

Resistance to chemotherapy-induced apoptosis and a multidrug-resistance (MDR) phenotype, mainly mediated by P-glycoprotein (P-gp), contribute to chemotherapy failure in hematologic malignancies. To study apoptosis-regulating factors in acute myeloid leukemia (AML), we investigated cell samples of adults with de novo AML by flow cytometry for constitutive expression levels of the apoptosis-related molecules CD95 (n = 135), Bcl-2 (n = 131), and Bax (n = 66), as well as spontaneous apoptosis in vitro (n = 104) and susceptibility to anti-CD95-induced apoptosis (CD95 sensitivity) (n = 93). We correlated these findings with P-gp function as detected by the rhodamine123-efflux test (n = 121), immunophenotype, FAB morphology, cytogenetics, and clinical data of the examined patients. Immature FAB M0/1 AML cells expressed significantly more Bcl-2 (P < 0.0002) and less CD95 (P < 0.0003) compared with AML cells of the more mature FAB M2-5 subtypes. No maturation-dependent difference in Bax expression was observed. FAB M2-5 AML cells were more susceptible to anti-CD95-induced apoptosis (P < 0.008) and showed a lower P-gp function (P < 0.002) than FAB M0/1 AML cells. Leukemic cells of AML patients who achieved a complete remission (CR) after induction chemotherapy expressed less Bcl-2 than non-responder (NR) (69 CR, 23 NR; P = 0.05). CR was associated with a higher extent of spontaneous apoptosis in vitro (58 CR, 17 NR; P=0.05) and a tendency towards a higher CD95 expression (73 CR, 23 NR; P = 0.08) compared to NR. CR also correlated with a low P-gp function (70 CR, 21 NR; P = 0.008) and a tendency towards CD34 negativity (73 CR, 23 NR; P = 0.08). No correlation between Bax expression and response to induction chemotherapy (49 CR, 12 NR) was observed. In stepwise logistic regression analyses, P-gp function and the extent of spontaneous apoptosis in vitro as well as CD95 sensitivity but not Bcl-2, CD95, Bax, and CD34 expression levels emerged as significant markers for response to induction chemotherapy. We conclude that the constitutive expression of CD95 and Bcl-2, as well as CD95 sensitivity and P-gp function but not constitutive Bax expression depend on the maturation stage of leukemic cells in adult de novo AML. P-gp function, the extent of spontaneous apoptosis in vitro and CD95 sensitivity are more predictive for response to induction chemotherapy in adult de novoAML than the constitutive expression levels of the apoptosis-related molecules CD95, Bcl-2 and Bax.     

胃癌中P-糖蛋白、多药耐药相关蛋白、肺耐药蛋白的表达及其意义

 目的　检测胃癌组织中P-糖蛋白（P-gp）、多药耐药相关蛋白（MRP）、肺耐药蛋白（LRP）的表达,分析其与胃癌临床病理因素的关系。方法　采用免疫组织化学SP法对59例胃癌患者癌组织进行研究。结果　在59例胃癌患者中P-gp阳性率最高[86.4 %（51例）],其次为LRP[84.7 %（50例）],二者呈正相关（r＝0.803）;MRP阳性率最低[27.1 %（16例）]。P-gp、MRP、LRP与分化程度无关（均P＞0.05）。P-gp与临床分期呈正相关（r＝0.742）,MRP、LRP均与胃癌浸润深度、淋巴结转移与否及分化程度无关。结论　P-gp、MRP、LRP在未接受化疗胃癌组织中高表达,提示胃癌中存在P-gp、MRP、LRP介导的原发性耐药。     

CD34/CD117 positivity in assessment of prognosis in children with myelodysplastic syndrome

Myelodysplastic syndromes (MDS) are a heterogeneous group of clonal stem cell disorders that are characterized by morphology identifying dysplastic changes in one or more cell lineages, peripheral blood cytopenias and a propensity to evolve into secondary acute myeloid leukemia (AML). CD34 is commonly expressed in all types of childhood leukemias, whereas CD117 is a reliable and specific marker to detect leukemia cells committed to myeloid lineage. Co-expression of CD34/CD117 may strongly suggest the diagnosis of AML (Rytting ME. Pediatric myelodysplastic syndromes. Curr hematol Rep 2004;3(3):173-7. May; U?kan D, Hi?s?nmez G, Yetgin S, Gürgey A, Cetin M, Karaa?ao?lu E, et al. CD34/CD117 co-expression in childhood acute leukemia. Leukemia Res 2000;24:201-6.). We describe the case of a 22 month-old-girl with MDS and Down syndrome who was presented with severe anemia and thrombocytosis at diagnosis, transformed into AML-M7. In our patient, CD34 and CD117 markers were positive on the blast cells of the BM 6 months before the chemotherapy decision. As the disease progressed, CD34/117 co-existence was increased and MDS transformed into AML. As a result, an increase in CD34 and CD117 positivity of the BM blast cells may be associated with a higher risk of leukemic transformation.     

Telomerase activity in myelodysplastic syndromes

Myelodysplastic syndromes are clonal hematopoietic stem cell disorders characterized by ineffective hematopoiesis and peripheral cytopenias. Telomeres are thought to be critical in maintaining normal hematopoiesis. In this study, we assessed telomere dynamics in order to obtain further insight into the pathogenesis of MDS. We studied telomerase activity (TA) in mononuclear cells from peripheral blood (PB) and bone marrow (BM) from patients with myelodysplastic syndrome (MDS; n=24), acute myeloid leukemia (AML; n=14), chronic myeloid leukemia (CML; n=12) and 11 normal controls using a polymerase chain reaction-based telomeric repeat amplification assay. Telomerase activities (mean+/-S.D.) were found as 0.199+/-0.09, 0.414+/-0.55, 0.253+/-0.26 and 0.181+/-0.05 pg/ml in PB mononuclear cells, respectively (P>0.05). Comparison of TA of BM mononuclear cells from 19 MDS patients versus 10 BM samples from normal controls revealed no significant difference (P=0.3). There was no correlation between the levels of TA and clinical and prognostic parameters of the patients with MDS, such as degree of anemia, platelet counts on presentation, gender, presence of organomegaly, bone marrow fibrosis and BM blast percentages. Patients who had higher TA had significantly inferior survival compared with patients who had lower TA (P=0.005). Consistent with previous data, our results suggest that in patients with MDS, telomerase activity might be insufficient to compensate for the telomere shortening. Furthermore, TA might be prognostically important in patients with MDS. Measurements of enzymatic activity in association with telomere length studies may help to understand the prognostic role of telomere dynamics in patients with myelodysplastic syndromes more reliably.