卵巢癌多细胞球体对紫杉醇耐药及其机制的探讨

背景和目的:多细胞球体(multicellularspheroids,MCS)对传统细胞毒化疗药物的敏感性明显低于单层细胞。本实验旨在探讨卵巢癌MCS耐药的分子机制。方法:以单层细胞为对照,以三维培养方法获得的人卵巢癌A2780MSC和CAOV3MCS为模型,采用台盼蓝拒染法比较紫杉醇对单层细胞和MCS生长的抑制作用,流式细胞仪比较单层细胞和MCS细胞周期的分布和细胞凋亡率;采用流式细胞仪、蛋白质免疫印迹法、激光共聚焦显微镜检测单层细胞及MCS的P-糖蛋白(P-glycoprotein,P-gp)表达及亚细胞分布;采用RT-PCR法检测mdr1mRNA表达水平。结果:(1)不同浓度的紫杉醇(0.2、2.0、10.0、20.0μmol/L)作用后,MCS细胞生长抑制率明显低于单层细胞(PA2780=0.003,PCAOV3=0.015);经20.0μmol/L的紫杉醇作用后,单层细胞的细胞凋亡率明显高于MCS,差异有统计学意义(PA2780=0.034,PCAOV3=0.032)。(2)流式细胞仪、蛋白质免疫印迹法、激光共聚焦显微镜检测提示P-gp在单层细胞中不表达,在MCS中表达明显升高(P均<0.05);RT-PCR证实MCS中有mdr1mRNA表达,而单层细胞中未检出其表达。(3)流式细胞仪检测提示将单层细胞培养成MCS时,G0/G1期细胞比率增加,S期和G2/M期细胞比率降低(P均<0.05)。结论:卵巢癌MCS对紫杉醇化疗耐药性增加,其高表达P-gp,并且与G0/G1期细     

Multicellular-mediated resistance to cisplatin and taxol in human ovarian cancer SK-OV-3IP1 multicellular aggregates

Chemotherapy is playing an increasingly important role in treatment of patients with advanced ovarian cancer. However, multidrug resistance (MDR) whether intrinsic or acquired- remains one of the most significant obstacles to survival improvement. A number of possible mechanisms have been put forward to account for drug resistance[1]. However, most of these proposed mechanisms are based largely on the study of drug- resistant variants isolated from tumor cell lines exposed to various classes …     

肺癌耐药发生和细胞周期改变的流式细胞术分析

目的　探讨肺癌耐药发生过程中多药耐药相关蛋白 (multidrugresistance associatedprotein ,MRP)、P 糖蛋白表达和细胞周期改变的关系。方法　采用低浓度阿霉素 (ADM)诱导人肺腺癌GLC 82细胞系 ,通过流式细胞术双参数标记检测MRP、P 糖蛋白表达和细胞周期的变化。结果　低浓度可明显降低GLC 82肺癌细胞系细胞周期中G1期比例 ,增加S期比例 ;P 糖蛋白表达极弱 ,MRP表达率明显增加 ,呈时间依赖性 ,其表达与细胞周期中S期比例变化呈正相关 (r =0 .87,P =0 .0 0 0 1)。结论　MRP表达可能是肺癌细胞耐药发生的重要参与机制 ,其表达与细胞周期中S期的变化相关。     

Cell cycle regulation of menin expression.

The multiple endocrine neoplasia type 1 gene product, menin, interacts with Jun D. The physiological role of menin in cell cycle control and the manner in which its inactivation contributes to tumorigenesis remain unknown. In the present study, the expression of menin was examined at various cell cycle stages in GH4C1 cells, a rat pituitary cell line. Cells synchronized at the G1-S-phase boundary expressed menin at a lower level than G0-G1-synchronized cells. The expression of menin increased as the cells entered S phase, at which time Jun D expression also increased. In contrast, cells synchronized at the G2-M phase expressed lower levels of menin. At G0-G1, G1-S, and G2-M phases of the cell cycle, menin was found predominantly in the nucleus. In summary, we show that in pituitary cells, menin is a nuclear protein whose expression is cell-cycle regulated. The data suggest that menin has an important role in cell growth regulation.     

15-Deoxy-Δ<Superscript>12,14</Superscript>-prostaglandin J<Subscript>2</Subscript> inhibits G<Subscript>2</Subscript>-M phase progression in human breast cancer cells via the down-regulation of cyclin B1 and survivin expression

The cyclopentenone prostaglandin 15-deoxy-Δ^12,14-prostaglandin J₂ (15d-PGJ₂) exerts a growth inhibitory effect on cancer cells, and this effect is linked to the induction of apoptosis or cell cycle arrest. Induction of apoptosis by 15d-PGJ₂ is associated with the down-regulation of anti-apoptotic proteins. G₀-G₁→S phase progression is inhibited by 15d-PGJ₂ via the degradation of cyclin D1. In this study, we further investigated the mechanism by which 15d-PGJ₂ inhibits cancer cell growth by using the breast cancer cell lines MCF-7 and T-47D. Treatment with 20 μM 15d-PGJ₂ for 72 h completely blocked the growth in both cell lines. However, the proportions of apoptotic MCF-7 and T-47D cells were 21.1% and 40.9%, respectively, indicating that the induction of apoptosis did not appear to fully account for growth inhibition by 15d-PGJ₂. Cell cycle analysis using cells synchronized at the G₀-G₁ or S phase revealed that 15d-PGJ₂ blocked not only G₀-G₁→S phase progression but also G₂-M phase progression. The expression of both cyclins D1 and B1 was decreased by 15d-PGJ₂. Furthermore, 15d-PGJ₂ inhibited aurora-B kinase activity, which coincided with the down-regulation of survivin. Thus, 15d-PGJ₂ induced cell cycle arrest at the G₂-M phase via inhibition of cyclin B1 expression and aurora-B kinase activity. We conclude that survivin may be an important target for 15d-PGJ₂, and its down-regulation may lead to a decrease in aurora-B kinase activity. Naoki Tsuji substantially contributed to this work and should also be considered a first author.     

Mechanistic Analysis of Taxol-induced Multidrug Resistance in an Ovarian Cancer Cell Line

Objectives: To establish a taxol-resistant cell line of human ovarian carcinoma (A2780/Taxol) and investigateits biological features. Methods: The drug-resistant cell line (A2780/Taxol) was established by continuous stepwiseselection with increasing concentrations of Taxol. Cell morphology was assessed by microscopy and growth curveswere generated with in vitro and in vivo tumor xenograft models. With rhodamine123 (Rh123) assays, cell cycledistribution and the apoptotic rate were analyzed by flow cytometry (FCM). Drug resistance-related and signalassociated proteins, including P-gp, MRPs, caveolin-1, PKC-α, Akt, ERK1/2, were detected by Western blotting.Results: A2780/Taxol cells were established with stable resistance to taxol. The drug resistance index (RI) was430.7. Cross-resistance to other drugs was also shown, but there was no significant change to radioresistance.Compared with parental cells, A2780/Taxol cells were significantly heteromorphous, with a significant delay inpopulation doubling time and reduced uptake of Rh123 (p < 0.01). In vivo, tumor take by A2780 cells was 80%,and tumor volume increased gradually. In contrast, with A2780/Taxol cells in xenograft models there was notumor development. FCM analysis revealed that A2780/Taxol cells had a higher percentage of G0/G1 and lowerS phase, but no changes of G2 phase and the apoptosis rate. Expression of P-gp, MRP1, MRP2, BCRP, LRP,caveolin-1, PKC-α, Phospho-ERK1/2 and Phospho-JNK protein was significantly up-regulated, while Akt andp38 MARK protein expression was not changed in A2780/Taxol cells. Conclusion: The A2780/Taxol cell line isan ideal model to investigate the mechanism of muti-drug resistance related to overexpression of drug-resistanceassociated proteins and activation of the PKC-α/ERK (JNK) signaling pathway.     

K252a inhibits proliferation of ovarian cancer cells by upregulating p21WAF1

The furanosylated indolocarbazole, K252a, belongs to a family of microbial alkaloids that also includes staurosporine, which is known to inhibit proliferation, stimulate apoptosis and induce cell cycle arrest of cancer cells. To elucidate the involvement of K252a in ovarian cancer, we investigated the effects of K252a on the ovarian cancer cell line, SK-OV-3. SK-OV-3 cells were treated with K252a, and its effect on cell growth, cell cycle, and related measurements was assessed. MTT assays showed that the ovarian cancer cell line SK-OV-3 cells were sensitive to the growth inhibitory effect of K252a. Cell cycle analysis indicated that their exposure to K252a decreased the proportion of cells in the S-phase and increased the proportion of cells in the G0/G1 phase of the cell cycle. This occurred in concert with altered expression of p21WAF1 protein related to the G0/G1 phase of the cell cycle. These results raise the possibility that K252a may prove particularly effective in treatment of ovarian cancer.     

阿霉素诱导人肝癌细胞多药耐药株的建立及其生物学特性评价

背景与目的:多药耐药(multidrugresistance,MDR)是肿瘤治疗的主要障碍,为探讨体外逆转肿瘤MDR的新方法,本研究建立人肝癌细胞多药耐药模型HepG2/Adm,并研究其生物学特性。方法:以人肝癌细胞株HepG2为研究对象,用阿霉素(adriamycin,ADM)浓度梯度递增诱导法,建立HepG2/Adm。观察细胞的生长规律;用MTT法检测多药耐药性;流式细胞术检测细胞周期分布、细胞表面多药耐药基因(mdr1)的表达产物P-糖蛋白(P-glycoprotein,P-gp)、多药耐药相关蛋白(multidrugresistance-associatedprotein,MRP)、肺耐药蛋白(lung-relatedprotein,LRP)及谷胱甘肽S-转移酶(glutathioneS-transferase,GST)的表达;逆转录PCR半定量检测4种MDR基因mRNA表达量。结果:与HepG2细胞比较,HepG2/Adm细胞倍增时间延长30.01h,S期细胞减少(5.6±0.03)%,G1、G2期细胞增多犤(4.2±0.09)%,(1.5±0.08)%犦。该细胞对多种抗肿瘤药物耐药,HepG2/Adm对阿霉素的耐药指数是亲本细胞的26倍,细胞表面多药耐药蛋白P-gp、MRP及GST的表达显著增加,LRP表达有一定的增加;上述四种耐药蛋白基因的表达均明显增加。结论:HepG2/Adm细胞具有多药耐药特性,其耐药性与P-gp、MRP及GST的过表达有关。     

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.     

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.     

人子宫内膜癌体外化学药物敏感性的实验研究

目的 利用人子宫内膜癌细胞株(HECCL-1)筛选对人子宫内膜癌敏感的化学药物,并探讨其作用机制。方法 采用四甲基偶氮唑蓝(MTY)法体外药敏实验检测HECCL-1细胞对18种不同浓度的化学药物的敏感性。利用流式细胞仪(FCM)进行细胞周期分析,并检测细胞凋亡率及用药前后多药耐药基因MDR1的表达。结果 MTY法结果显示,部分化学药物可显著抑制HECCL-1细胞的增殖,且呈剂量依赖效应,敏感性药物依次为阿霉素、奥铂、卡铂、顺铂、泰素、表阿霉素、放线菌素D、米托葸醌和氟脲嘧啶。FCM检测结果显示,化学药物作用后G0期、G1期细胞显著减少,S期、G2期、M期细胞显著增加。在血浆峰值浓度(PPC)下,11种化学药物作用于HECCL-1细胞后出现细胞凋亡图像。表阿霉素、氟脲嘧啶、羟基喜树碱、米托葸醌4种药物作用后诱导出MDR1阳性表达。结论 HECCL-1是一种化学药物较敏感的细胞株,多种化学药物能够显著抑制HECCL-1细胞的增殖活性,改变其细胞周期分布;诱导细胞凋亡是化学药物作用于该细胞的重要机制;获得性耐药是继续用药失败的主要原因。     

INFLUENCE OF p53 SMALL DOUBLE STRANDED RNA INTERFERENCE ON HEPATOMA CELL LINE SK-HEP-1

Hepatocellular carcinoma is one of the most frequentmalignant diseases worldwide,especially with annualgradually increasing incidence in China.From the firstconcept of tumor suppressor being set up by Knudson[1],many studies have showed that there in very highmutation frequency in the evolutionarily conservedcodons of the p53tumor suppressor gene,which iscommon in diverse types of human cancers[2].The p53gene encodes a nuclear phosphoprotein of53-kDa masswhich belongs to a diverse family of n…     

DIFFERENTIAL EXPRESSION OF ADHESION MOLECULES （CD44，CD29，ICAM-1 AND E-CADHERIN）IN OVARIAN CANCER SK-OV-3ip1 CELLS GROWN AS MONOLAYER AND MULTICELLULAR AGGREGATES

Multidrug resistance (MDR) -whether intrinsic or acquired- remains one of the most significant obstacles to survival improvement for patients with advanced ovarian cancer[1]. Solid tumors are composed of many microregions divided by angiogenesis. Multicellular aggregates (MCA) are cell aggregates formed by growing tumor cells three-dimensionally and characterized by solid tumor microenvironment and therefore can exactly stand for a microregion in vitro[2]. Our previous research has found inc…     

miR-152在急性髓系白血病患者骨髓和细胞系中的表达及生物学功能的初步研究

目的:检测miR-152在急性髓系白血病(AML)患者骨髓和细胞系中的表达水平。初步研究miR-152在急性髓系白血病中的生物学功能。方法:收集急性髓系白血病患者40例,非恶性血液病对照组20例,提取骨髓有核细胞;培养U937、Kasumi-1、THP-1三种急性髓系白血病细胞系。RT-PCR检测miR-152的表达水平。分别对U937细胞系和Kasumi-1细胞系转染miR-152 mimics和inhibitor,CCK-8法检测U937细胞及Kasumi-1细胞增殖情况,Annexin V/PI流式实验检测细胞凋亡,流式细胞术检测细胞周期。结果:miR-152在急性髓系白血病患者骨髓及细胞系中较非恶性血液病对照组表达明显下降。U937细胞系转染miR-152 mimics后,增殖受抑制,细胞凋亡增加,细胞阻滞在G0-G1期;Kasumi-1细胞系转染miR-152 inhibitor后,增殖增加,细胞凋亡减少,G0-G1期细胞减少。结论:miR-152在急性髓系白血病患者骨髓及细胞系中的表达水平均较正常对照组显著降低。miR-152在急性髓系白血病中起抑癌基因的作用,过表达miR-152可以抑制细胞增殖,促进凋亡。     

Experimental Study on the Mechanism of Reversal of Leukemia Multidrug Resistance by Proteasome Inhibitor Bortezomib

OBJECTIVE In this study, we applied multidrug resistant leukemia cell line expressing mdr1-mRNA to observe changes in mdr1-mRNA, the P-gp, cell cycle and apoptosis before and after bortezomib was used, in order to explore the mechanism of reversal of leukemia multidrug resistance by the proteasome inhibitor bortezomib.METHODS Flow cytometry (FCM) was used to detect the intracellular drug concentration, expression of P-gp, cell apoptosis and cell cycle status of K562/DNR cells before and a er treatment with different concentrations of bortezomib. Fluorescence quantitative PCR was applied to detect the mdr1-mRNA expression in K562/DNR and K562/S cells.RESULTS Bortezomib could increase the intracellular DNR content in K562/DNR cells, but showed no e. ect in K562/S cells.5-100 nmol/L bortezomib could significantly reduce the P-gp/mdr1-mRNA expression in K562/DNR cells in vitro, and showed a dose-dependent effect. There was a statistically significant di. erence (P < 0.05) between di. erent concentration groups and the control group. P-gp/mdr1-mRNA expression was negatively correlated with cell apoptosis (r = -0.912 and P < 0.01). After treatment with different concentrations of bortezomib for 24 h,K562/DNR cells in G2 + M phases were significantly increased,while cells in G0 + G1 phases and S phase were significantly decreased, accompanied by an increased apoptotic rate.CONCLUSION Bortezomib can induce G0 + G1 phase to G2 + M phase, and thereby enhance the chemosensitivity of leukemia, and may also reverse the multidrug resistance in leukemia mediated by P-gp overexpression encoded by mdr1 gene. This confi rms that bortezomib can reverse leukemia multidrug resistance at the levels of nucleic acid and protein molecules.     

塞来昔布逆转MCF-7/Adr细胞多药耐药及其机制探讨

目的观察环氧合酶-2（COX-2）抑制剂塞来昔布对肿瘤多药耐药（MDR）的逆转作用,并探讨其初步作用机制。方法在乳腺癌耐药细胞株MCF-7/Adr中,应用MTT方法检测塞来昔布对多柔比星（阿霉素,DOX）的耐药逆转倍数;RT-PCR及Western blot方法检测基因及蛋白的变化;流式细胞术（FCM）检测细胞膜P-gp的表达、功能、细胞周期和凋亡。结果塞来昔布作用24小时后,MCF-7/Adr细胞对DOX的敏感性明显增加,浓度为10μmol/L及20μmol/L时,耐药逆转倍数分别为1.82和3.80,呈现剂量依赖性。COX-2、mdr1、c-Jun、YB-1、survivin等在基因和蛋白水平明显下调（P〈0.01）,NF-κB无明显差异（P〉0.05）;20μmol/L作用24小时,P-gp的功能受抑制;G0＋G1期细胞增多,S期细胞减少（P〈0.05）,凋亡率明显增高（P〈0.05）。结论选择性环氧合酶-2抑制剂塞来昔布可有效逆转MCF-7/Adr细胞多药耐药,在一定的浓度范围内呈现剂量依赖性,初步机制可能涉及干预转录因子的表达而下调mdr1,阻滞细胞周期及增加细胞凋亡。     

Multidrug resistance proteins in rhabdomyosarcomas: comparison between children and adults

BACKGROUND: Pediatric rhabdomyosarcomas (RMS) have a more advantageous prognosis after multimodality treatment compared with adult RMS, which might be related to a decreased sensitivity to chemotherapy in adults. Resistance to chemotherapy might be conveyed by the multidrug resistance (MDR)-associated proteins P-glycoprotein (P-gp), multidrug resistance-associated protein 1 (MRP1), and lung resistance-related protein (LRP). It was therefore suggested that these proteins were expressed differently in pediatric and adult patients. METHODS: The expression of P-gp, MRP1, and LRP was assessed immunohistochemically in 45 specimens of untreated RMS: 29 were obtained from children younger than 16 years old and 16 were obtained from adults. All children had an embryonal or botryoid RMS. Among the adults, there were 10 embryonal, 3 alveolar, and 3 pleomorphic RMS. Samples were scored as negative or positive according to the percentage of immunoreactive tumor cells: 0.5 (1-5%), 1 (5-25%), 2 (26-50%), 3 (51-75%), or 4 (> 75%). RESULTS: Expression of LRP was more pronounced in embryonal and pleomorphic RMS in adults compared with RMS in children. In addition, LRP expression correlated with age at diagnosis. Alveolar RMS had remarkably low LRP expression. Expression of P-gp and MRP1 did not differ significantly between children and adults. CONCLUSIONS: In this series of embryonal and pleomorphic RMS, an increased LRP expression was observed in adults, which may explain their worse response to chemotherapy reported in other studies. In alveolar RMS, a low LRP expression was observed, suggesting that other mechanisms are responsible for the resistant phenotype in most of these tumors.     

The distribution of drug-efflux pumps, P-gp, BCRP, MRP1 and MRP2, in the normal blood-testis barrier and in primary testicular tumours

The drug-efflux pumps P-glycoprotein (P-gp) and multidrug resistance-associated protein 1 (MRP1) are present in the blood-testis barrier (BTB) and may hamper the delivery of cytotoxic drugs to the testis. The precise localisation of P-gp and MRP1 in testicular tissue and the presence of the efflux pumps MRP2 and breast cancer resistance protein (BCRP) in the BTB are unknown. We therefore studied the localisation of these pumps in the BTB in normal testis (n = 12), in non-seminoma (n = 10) seminoma (n = 10), and testicular lymphoma (n = 9). Slides were scored semi-quantitatively for P-gp, MRP1, MRP2 and BCRP and blood vessels with factor VIII antibody. In normal testis, P-gp and BCRP were strongly expressed by myoid cells and luminal capillary endothelial wall and P-gp also by Leydig cells. MRP1 was observed at the basal side of Sertoli cells and on Leydig cells. MRP2 was only weakly expressed by myoid cells. Seminomas and non-seminomas expressed P-gp and/or BCRP and/or MRP1, lymphomas strongly expressed P-gp, weakly expressed BCRP and did not or showed weak expression of MRP1. There was very little staining for MRP2 in the tumours. Newly formed vessels in all tumours only expressed P-gp and BCRP. P-gp, BCRP and MRP1 are present in different cell layers of the normal testis, suggesting the optimal protection of spermatogenesis. In germ cell tumours, this expression pattern may explain the chemoresistance observed to P-gp, BCRP and MRP1 substrates. In germ cell tumours and testicular lymphomas, P-gp and BCRP expression by tumour cells and by newly formed vessels may also contribute to chemoresistance. These findings underscore the importance of removing the affected testis in cases of primary germ cell tumours and testicular lymphomas, irrespective of whether the patient has already undergone chemotherapy.