JNK1,JNK2,and JNK3 are involved in P-glycoprotein-mediated multidrug resistance of hepatocellular carcinoma cells

BACKGROUND:Multidrug resistance(MDR)is extremely common in hepatocellular carcinoma(HCC)and is a major problem in cancer eradication by limiting the efficacy of chemotherapy.Modulation of c-Jun NH2-terminal kinase(JNK)activation could be a new method to reverse MDR.However,the relationship between JNK activity and MDR in HCC cells is unknown.This study aimed to explore the relationship between MDR and JNK in HCC cell lines with different degrees of MDR.METHODS:A MDR human HCC cell line,SMMC-7721/ ADM,was developed by exposing parental cells to gradually increasing concentrations of adriamycin.The MTT assay was used to determine drug sensitivity.Flow cytometry was used to analyze the cell cycle distribution and to measure the expression levels of P-glycoprotein(P-gp)and MDR-related protein(MRP)-1 in these cells.JNK1,JNK2 and JNK3 mRNA expression levels were quantified by real-time PCR.Expression and phosphorylation of JNK1,JNK2,and JNK3 were analyzed by Western blotting.RESULTS:The MDR of SMMC-7721/ADM cells resistant to 0.05 mg/L adriamycin was mainly attributed to the overexpression of P-gp but not MRP1.In addition,these cells had a significant increase in percentage in the S phase,accompanied by a decrease in percentage in the G0/G1 phase,which is likely associated with a reduced ability for cell proliferation and MDR generation.We found that JNK1,JNK2,and JNK3 activities were negatively correlated with the degree of MDR in HCC cells.CONCLUSION:This study suggests that JNK1,JNK2,and JNK3 activities are negatively correlated with the degree of MDR in HCC cells.

Down-regulation of extracellular signal-regulated kinase 1/2 activity in P-glycoprotein-mediated multidrug resistant hepatocellular carcinoma cells

AIM： To study the expression and phosphorylation of extracellular signal-regulated kinase （ERK） i and ERK2 in multidrug resistant （MDR） hepatocellular carcinoma （HCC） cells.METHODS： MDR HCC cell lines, HepG2/adriamycin （ADM） and SMMC7721/ADM, were developed by exposing parental cells to stepwise increasing concentrations of ADM. MTT assay was used to determine drug sensitivity. Flow cytometry was employed to analyze cell cycle distribution and measure cell P-glycoprotein （P-gp） and multidrug resistant protein 1 （MRP1） expression levels. ERK1 and ERK2 mRNA expression lev-ls were measured by quantitative real-time PCR （QRTPCR）. Expression and phosphorylation of ERK1 and ERK2 were analyzed by Western blot.RESULTS： MTT assay showed that HepG2/ADM andSMMC7721/ADM were resistant not only to ADM, but also to multiple anticancer drugs. The P-gp expression was over 10-fold higher in HepG2/ADM cells than in HepG2 cells （8.92% ±0.22% vs 0.88% ± 0.05%, P 〈 0.001） and over 4-fold higher in SMMC7721/ADM cells than in SMMC7721 cells （7.37% ± 0.26% vs 1.74% ± 0.25%, P 〈 0.001）. However, the MRP1 expression was not significantly higher in HepG2/ADM and SMMC7721/ADM cells than in parental cells. In addition, the percentage of MDR HepG2/ADM and SMMC7721/ADM cells was significantly decreased in the G0/G1 phase and increased in the the S phase or G2/M phase. QRT-PCR analysis demonstrated that the ERK1 and ERK2 mRNA expression increased apparently in HepG2/ADM cells and decreased significantly in SMMC7721/ADM cells. Compared with the expression of parental cells, ERK1 and ERK2 protein expressions were markedly decreased in SMMC7721/ADM cells. However, ERK2 protein expression was markedly increased while ERK1 protein expression had no significant change in HepG2/ADM cells. Phosphorylation of ERK1 and ERK2 was markedly decreased in both HepG2/ADM and SMMC7721/ADM MDR cells.CONCLUSION： ERK1 and ERK2 activities are downregulated in P-gp-mediated MDR HCC cells. ERK1 or ERK2 might be a potential drug target for circumventing MDR HCC cells,

Reversal of multidrug resistance of hepatocellular carcinoma cells by metformin through inhibiting NF-κB gene transcription

AIM: To interfere with the activation of nuclear factor-κB(NF-κB) with metformin and explore its effect in reversing multidrug resistance(MDR) of hepatocellular carcinoma(HCC) cells.METHODS: Expression of P-glycoprotein(P-gp) and NF-κB in human HepG 2 or HepG 2/adriamycin(ADM) cells treated with pC MV-NF-κB-small interference RNA(siR NA) with or without metformin, was analyzed by Western blot or fluorescence quantitative PCR. Cell viability was tested by CCK-8 assay. Cell cycle and apoptosis were measured by flow cytometry and Annexin-V-PE/7-AnnexinV apoptosis detection double staining assay, respectively. RESULTS: P-gp overexpression in HepG 2 and HepG 2/ADM cells was closely related to mdr1 mR NA(3.310 ± 0.154) and NF-κB mR NA(2.580 ± 0.040) expression. NF-κB gene transcription was inhibited by specific siR NA with significant down-regulation of P-gp and enhanced HCC cell chemosensitivity to doxorubicin. After pretreatment with metformin, Hep G2/ADM cells were sensitized to doxorubicin and P-gp was decreased through the NF-κB signaling pathway. The synergistic effect of metformin and NF-κB siR NA were found in HepG 2/ADM cells with regard to proliferation inhibition, cell cycle arrest and inducing cell apoptosis. CONCLUSION: Metformin via silencing NF-κB signaling could effectively reverse MDR of HCC cells by downregulating MDR1/P-gp expression.

Hepatocellular carcinoma and multidrug resistance: Past, present and new challenges for therapy improvement

Hepatocellular carcinoma(HCC) is the most frequent form of liver cancer and the third most common cause of cancer-related death in the world. The main risk factor worldwide for this type of malignancy is chronic hepatitis caused by hepatitis B virus and hepatitis C virus infections. Advances in early detection and treatmenthave improved life expectancy of patients with HCC. However, this disorder remains as a disease with poor prognosis. In fact, epidemiological studies have revealed that there is an 8-mo median survival rate in patients, approximately 20% of whom survive one year while only 5% remain alive after three years. Additionally, HCC is particularly difficult to treat because of its high recurrence rate, and its resistance to conventional chemotherapy is due, among other mechanisms, to several members of the ATP-Binding Cassette protein family involved in drug transport being overexpressed. Fortunately, there is evidence that these patients may benefit from alternative molecular-targeted therapies. This manuscript intends to provide further insight into the etiology and molecular mechanisms related to HCC development and the latest therapeutic approaches to treat this malignancy. The development of effective delivery systems of antitumor drugs able to target the liver parenchyma is also assessed. Finally, the prospects in the development of more efficient drug therapies to overcome multidrug resistance are also examined.

Reversal of Adriamycin Resistance of Hepatocellular Carcinoma by Targeting with Recombined Adenovirus Caning Antisense mdr1 RNA

OBJECTIVE Chemotherapy is an important therapy for hepatocellular carcinoma （HCC）. However, it is not effective in many cases due to recurrence and metastasis even if the initial treatment produces a response. Multidrug resistance （MDR） is considered to be one of the considerable causes. The aim of this study was to reverse MDR of HepG2/ADM cells by blocking mdr1 with an adenovirus vector carrying antisense mdr1 in a tumor transplantated in athymic mice. METHODS PCMV IE was removed from the pshuttle vector. A 0.3 kb AFP promoter was inserted into the pshuttle vector and pCMV changed into pAFP. The pAFP and asmdr1 PCR products were doubly digested with Kpnl and Apal, the digested products were ligated by T4 ligase, the asmdr1 gene was inserted into pAFP and a newly plasmid pAFP-asmdr1 was constructed. Following digestion with PI-SceI/I-Ceu I, pAFP-asmdr1 was ligated with Adeno-X genome DNA and amplified in E.coli XL1-Blue. The HEK293 cells were transfected and virus collected. The HepG2 MDR cells （HepG2/ADM） were induced by graded resistance to ADM and were inoculated into athymic mice. After adeno-asmdr1 was injected, the expression of mdr1-mRNA and the volume of the transplantated tumor and its cells were observed. RESULTS Following injection with Adeno-asmdr1, the tumor volume in the ADM＋Adeno-asmdr1 group did not increase. However the tumor volume in the PBS plus ADM group did significantly increase （P〈0.05）. In the tumor xenograft cells, mdr1 mRNA in the xenografts was assessed by RT-PCR and was found to be reduced at 1 week and 4 weeks in the ADM＋asmdr1 group, but it was stable in the ADM group. It was only 20% in the ADM＋asmdr1 group compared to the ADM group at the 4th week （P〈0.05）. Evidence of apoptosis was observed in the tumor xenograft cells treated with Adeno-asmdr1, but there was rare or no apoptosis in the group treated with ADM and PBS. CONCLUSION Adenovirus carrying antisense mdr1 RNA can partially reverse the MDR of HepG2/ADM cells and inhibit tumor growth by down-regulating mdr1 mRNA resulting in tumor cell apoptosis.

Overexpression of P-glycoprotein in hepatocellular carcinoma and its clinical implication

INTRODUCTIONMost advanced hepatocellular garcinoma (HCC) isinsensitive to most anticancer drugs which might berelated to the high frequency of expression of themultidrug resistance-1(MDR1) gene and itsproduct,P-glycoprotein (p-gp).p-gp expressionmay also be concerned with tumor progression anddifferentiation.In the present study。

Reversing multidrug resistance by RNA interference through the suppression of MDR1 gene in human hepatoma cells

AIM： To reverse the multidrug resistance （MDR） by RNA interference （RNAi）-mediated MDRI suppression in heparoma cells.METHODS： For reversing MDR by RNAi technology, two different short hairpin RNAs （shRNAs） were designed and constructed into pGenSil-1 plasmid, respectively. They were then transfected into a highly adriarnycin-resistant HepG2 hepatorna cell line （HepG2/ADM）. The RNAi effect on MDR was evaluated by real-time PCR, cell cytotoxicity assay and rhodarnine 123 （Rh123） efflux assy. RESULTS： The stably-transfected clones showed various degrees of reversal of MDR phenotype. Surprisingly, the MDR phenotype was completely reversed in two transfected clones. CONCLUSION： MDR can be reversed by the shRNAmediated MDRI suppression in HepG2/ADM cells, which provides a valuable clue to make multidrug-resistant hepatoma cells sensitive to anti-cancer drugs.

CIK cells from patients with HCC possess strong cytotoxicity to multidrug-resistant cell line Bel-7402/R

ABM: To investigate the cytotoxicity of the cytokine-induced killer (CIK) cells from the post-operation patients with primary hepatocellular carcinoma (HCC) to multidrug-resistant (MDR) cell of HCC both in vitro and in vivo. METHODS: A drug-resistant cell line was established by culturing human HCC cell line Bel-7402 in complete RPMI 1640 medium with increasing concentrations of adriamycin from 10 to 2 000 nmol/L. CIK cells were obtained by inducing the peripheral blood mononuclear cells with rhlFN-γ, monoclonal anti-CD3 antibody, rhIL-1α as well as rhIL-2, which were added into the culture. To detect the cytotoxicity of the CIK cells from HCC patients, the Bel-7402/R was taken as target (T) cells and CIK cells as effect (E) cells. Cytotoxic test was performed and measured by MTT. As to in vivo test, CIK cells were transfused into patients with HCC. The tumor specimens of the patients were obtained and immunohistochemistry was carried out to detect CD3, CD45, CD45RO as well as CD68. RESULTS: A MDR 1 HCC cell line Bel-7402/R was established. Its MDR1 mRNA overexpressed which was shown by RT-PCR; the P-glycoprotein expression increased from 1.32% of parent cells to 54%. CIK cells expanded vigorously by more than 70-fold and the CD3+CD56+ increased by more than 600-fold after 3-wk incubation on average. The cytotoxicity of CIK from HCC patients to Bel-7402/R was about 50% and to L-02 below 10% (t = 8.87, P<0.01), the same as that of CIK from normal individuals. Each of the 17 patients received 1-5×1010of CIK cell transfusion. No side effects were observed. After CIK treatment, the tumor tissue nodules formed and a large amount of lymphocytes infiltrated in the liver cancer tissue and CD3, CD45, CD45RO, and CD68 increased greatly which was shown by immunohistochemistry. CONCLUSION: A stable MDR1 HCC cell line has been established which could recover from liquid nitrogen and CIK from HCC patients has strong cytotoxicity to MDR HCC cell. CIK adoptive immunotherapy is safe and has no side effects. Receivers improved their immunity to tumor evidently. CIK treatment may be a better choice for HCC patients after operation to prevent the recurrence, especially when tumors have developed drug resistance.

Promoter polymorphism of MRP1 associated with reduced survival in hepatocellular carcinoma

AIM:To investigate the effect of the G-1666A polymorphism in the multidrug resistance related protein-1 (MRP1) on outcome of hepatocellular carcinoma (HCC). METHODS:A cohort of 162 patients with surgically resected HCC who received no postsurgical treatment until relapse was studied. Genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism analysis. Electrophoretic mobility shift assay (EMSA) was used to evaluate the influence of the G-1666A polymorphism on the binding affinity of the MRP1 promoter with its putative transcription factors. RESULTS:Kaplan-Meier analysis showed that patients with GG homologues had a reduced 4-year disease-free survival compared with those carrying at least one A allele (P = 0.011). Multivariate Cox regression analysis indicated that the-1666GG genotype represented an independent predictor of poorer disease-free survival [hazard ratio (HR) = 3.067,95% confidence interval (CI):1.587-5.952,P = 0.001],and this trend became worse in men (HR = 3.154,95% CI:1.604-6.201,P = 0.001). A similar association was also observed between 4-year overall survival and the polymorphism in men (HR = 3.342,95% CI:1.474-7.576,P = 0.004). Moreover,EMSA suggested that the G allele had a stronger binding affinity to nuclear proteins. CONCLUSION:The MRP1-1666GG genotype predicted a worse outcome and was an independent predictor of poor survival in patients with HCC from Southeast China.

APOPTOTIC THRESHOLD OF ADRIAMYCIN AND CISPLATIN INHEPATOCELLULAR CARCINOMA

Objective: To investigate the apoptotic threshold of adriamycin (ADM) and cisplatin (CDDP) on hepatocellular carcinoma (HCC). Methods: Sensitivities of ADM and CDDP on HCC were studied by primary cell culture. Results: The apoptotic threshold of ADM and CDDP were 1.0 μg/ml and 1.5μg/ml respectively (its clinical dosage was 20 mg and 30 mg respectively). Conclusion: Understanding apoptotic threshold of anticancer drugs may reduce clinical dosages of anticancer drugs and reduce the incidence of multidrug resistance (MDR).

Establishment of hepatocellular carcinoma multidrug resistant monoclone cell line HepG2/mdr1

Background The multidrug resistance （MDR） associated with the expression of the mdr1 gene and its product P-glycoprotein is a major factor in the prognosis of hepatocellular carcinoma cell （HCC） patients treated with chemotherapy. Our study was to establish a stable HCC MDR cell line where a de novo acquisition of multidrug resistance specifically related to overexpression of a transgenic mdr1. Methods The 4.5-kb mdrl cDNA obtained from the plasmid pHaMDR1-1 was cloned into the PCl-neo mammalian expression vector, later was transferred by liposome to human hepatocarcinoma cell line HepG2. Then the transfected HepG2 cells resisting G418 were clustered and cultured and the specific fragment of mdr1 cDNA, mRNA and the P-glycoprotein （Pgp） in these HepG2 cells were detected by PCR, RT-PCR and flow cytometry, respectively. The accumulation of the daunorubicin was determinated by flow cytometry simultaneously. The nude mice model of grafting tumour was established by injecting subcutaneously HepG2/mdr1 cells in the right axilla. When the tumour diameter reached 5 mm, adriamycin was injected into peritoneal cavity. The size and growth inhibition of tumour were evaluated. Results The mdr1 expression vector was constructed successfully and the MDR HCC line HepG2/mdr1 developed. The PCR analysis showed that the specific fragment of mdrl cDNA in HepG2/mdr1 cells, but not in the control group HepG2 cells. Furthermore, the content of the specific fragment of mdr1 mRNA and Pgp expression in HepG2/mdr1 cells were （59.7±7.9）% and （12.28±2.09）%, respectively, compared with （16.9±3.2）% and （3.07±1.06）% in HepG2 cells. In the nude mice HCC model, the tumour genes of both groups were identified. After ADM therapy, the mean size of HepG2 cell tumours was significantly smaller than HepG2/mdr1 cell tumours. Conclusion The approach using the transfer of mdr1 cDNA may be applicable to the development of MDR hepatocarcinoma cell line, whose MDR mechanism is known. This would provide the experimental basis of MDR research.

Reversal of multidrug resistance in renal cell carcinoma by short hairpin RNA targeting MDR1 gene

Background Over-expression of P-glycoprotein （P-gp）, encoded by the MDR1 gene, confers multidrug resistance （MDR） in renal cell carcinoma （RCC） and is a major reason for unsuccessful chemotherapy. This study aimed to determine the effct of RNA interference （RNAi） on the reversal of MDR in human RCC. Methods We designed and selected one short hairpin RNA （shRNA） targeting MDR1 gene, which is stably expressed from integrated plasmid and transfected by lentivirus fluid in human RCC A498 cell. Results The MDRl-targeted RNAi resulted in decreased MDR1 gene mRNA level （P 〈0.001）, almost abolished P-gp expression and reversed MDR to different chemotherapy drugs in the RCC A498 cell line. Conclusion MDR could be reversed by RNAi in human RCC A498 cell line, which may be used for clinical application

Establishment and characterization of an oxaliplatin-resistant hepatic cancer cell line

Objective The aim of the current study was to establish an oxaliplatin-resistant hepatoma cell line(HepG2/OXA) and investigate the potential mechanisms of its drug resistance.Methods The hepatoma cell subline, HepG2/OXA, resistant to oxaliplatin(OXA), was established from a parent cell line HepG2, by stepwise exposure to gradually increasing concentrations of OXA over a half-year period. Chemosenstivity of the cytotoxic drugs, OXA, cisplatin(CDDP), adriamycin(ADM), and 5-fuorouracil(5-FU), was determined in HepG2 and HepG2/OXA cells, by the Cell counting kit-8(CCK8) assay. Cell cycle distribution of HepG2 and HepG2/OXA cells was analyzed by Flow cytometry(FCM). The expression levels of several drug resistance-related proteins, such as P-glycoprotein(P-gp), multidrug resistant protein 1(MRP1), and excision repair-cross complementing 1(ERCC1) protein in the two cell lines were tested by the western blot assay.Results The IC50 of OXA in HepG2/OXA and HepG2 were 136.84 μmol/L and 23.86 μmol/L, respectively. The resistance index(RI) was 5.34. HepG2 was also demonstrated to be cross-resistant to other antitumor agents, such as 5-FU, ADM, and CDDP. The percentage of HepG2/OXA cells in the S phase was significantly decreased compared to HepG2 cells(25.58% ± 2.36% vs 14.37% ± 2.54%, P < 0.05), while the percentage of cells in the G0/G1 and G2/M phases showed no statistical difference(respectively 55.29% ± 4.98% vs 56.73% ± 4.56%, P > 0.05, and 24.63% ± 4.81% vs 28.26% ± 3.82%, P > 0.05). The ERCC1 was found to be over expressed in HepG2/OXA cells, while there was no difference in the expressions of P-gp and MRP1 between the multiple drug resistance(MDR) phenotype cell line and its parental cell line.Conclusion HepG2/OXA showed an MDR ability; the over expression of ERCC1 might be associated with the platinum resistance of the cells, but P-gp and MRP1 are not.

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。

两种儿茶素成分体外逆转人肝癌细胞BEL-7404/ADR多药耐药性

背景与目的:儿茶素具有多种抗肿瘤的活性,目前,国内外尚未见儿茶素用于肝癌多药耐药性的研究。本研究拟探讨两种儿茶素成分表儿茶素没食子酸酯(epicatechingallate,ECG)和表没食子儿茶素没食子酸酯(epigallocatechingallate,EGCG)体外逆转人肝癌细胞多药耐药性的作用及可能的机制。方法:MTT法检测ECG、EGCG的细胞毒作用;荧光分光光度法检测细胞内化疗药物的含量;RT-PCR法检测mdr1基因的表达。结果:ECG和EGCG在100mg/L以下剂量时对耐药肝癌细胞株BEL-7404/ADR的抑制率均小于10%,60mg/L的ECG和14mg/L的EGCG分别与0.8mg/L的阿霉素(adriamycin,ADM)合用能使ADM对BEL-7404/ADR的IC50由36mg/L分别下降至2.3mg/L和1.9mg/L,增敏倍数分别为15.8倍和19.2倍,联合用药可使细胞内ADM的浓度由(0.76±0.02)μg/108cells～(2.55±0.17)μg/108cells提高到(2.04±0.07)μg/108cells～(9.28±0.59)μg/108cells(P<0.01),并使mdr1表达与对照组相比分别下降了27.6%及41.3%,逆转肿瘤MDR作用以EGCG为强。结论:EGCG和ECG具有体外逆转人肝癌细胞多药耐药性的作用,可能与下调mdr1表达、增加细胞内化疗药物的积累有关。

姜黄素对人肝癌耐药细胞株Bel7402/5-FU多药耐药性的逆转作用

目的:探讨姜黄素对人肝癌耐药细胞株Bel7402/5-FU多药耐药性的逆转作用及可能的作用机制.方法:采用氟尿嘧啶(fluorouracil,5-FU)药物浓度梯度递增法诱导建立肝癌耐药细胞亚系Bel7402/5-FU;MTT法检测人肝癌细胞株Bel7402及其耐药细胞株Bel7402/5-FU对6种化疗药物以及姜黄素的敏感性;Western blot法检测Bel7402细胞、Bel7402/5-FU细胞及经过0、5、10、20mg/L姜黄素作用后的Bel7402/5FU细胞中多药耐药相关蛋白1(MRP1)、肺耐药相关蛋白(LRP)、P-糖蛋白(P-gp)、程序化死亡因子5(PDCD5)蛋白的表达水平.结果:Bel7402/5-FU细胞对6种化疗药物表现出交叉耐药性,其中对5-FU耐药指数最高;与Bel7402细胞相比,Bel7402/5-FU细胞中的MRP1、LRP、P-gp蛋白表达升高,PDCD5蛋白表达降低;随姜黄素浓度的升高,Bel7402/5FU细胞中MRP1、LRP、P-gp蛋白表达逐渐降低,PDCD5蛋白表达逐渐增高.结论:姜黄素具有逆转肝癌细胞多药耐药性的作用,可能与下调多药耐药相关蛋白MRP1、LRP、P-gp,上调凋亡相关蛋白PDCD5表达有关.

三氧化二砷逆转肝癌细胞株HepG2／ADM多药耐药的作用

目的:探讨三氧化二砷(As2O3)体外逆转人肝癌细胞多药耐药性的作用及机制．方法:MTT法检测As2O3的细胞毒作用和处理前后耐药细胞对化疗药物的敏感性,用流式细胞仪检测细胞内阿霉素浓度,通过RT-RCR检测MDR1基因的表达．结果:As2O3在0．25 mg／L剂量以下时对HepG2和HepG2／ADM耐药细胞株的抑制率均小于15％,半数抑制率(IC50)分别为1．02和1．34 mg／L,无细胞毒剂量0．2 mg/L的As2O3能部分逆转HepG2／ADM细胞对阿霉素、顺铂(CDDP)、丝裂霉素(MMC)、5-氟尿嘧啶(5-FU)的耐药性,逆转倍数分别为2．92,3．09,2．13,2．60倍．同时无细胞毒剂量0．2 mg／L的As2O3能使HepG2／ADM细胞内阿霉素浓度明显增加,MDR1表达下降．结论:As2O3具有体外逆转人肝癌细胞多药耐药性的作用,可能与下调MDR1表达、增加细胞内药物积累有关．

柴胡逆转肝细胞癌多药耐药作用与相关机制的研究

选用对VCR天然耐药肝癌细胞株Bel-7402为对象来研究柴胡逆转MDR效果与相关的机制,以寻找一种新型的具有多药耐药逆转活性的中药.结果表明,柴胡具有逆转肝细胞癌多药耐药作用,并与抗癌药物VCR有协同作用.柴胡对人肝癌Bel-7402细胞株具有多药耐药逆转作用,提高了耐药细胞内的VCR含量,增加了VCR对细胞G2期阻滞作用,抑制了P-170糖蛋白的表达,抑制MDR1/mRNA的表达,提高了TopoαmRNA水平.

人肝癌BEL-7402/5-FU多药耐药细胞株的建立及其生物学特性观察

目的:建立人肝癌BEL-7402/5-FU多药耐药细胞株。方法:采用体外低浓度梯度递增联合大剂量间断冲击的诱导方法建立5-FU获得性BEL-7402/5-FU多药耐药细胞株。MTT法检测耐药细胞株对多种化疗药物的交叉耐药性。观察其细胞形态学、生长曲线、倍增时间、平板克隆形成率、贴壁率、细胞周期分布、染色体核型以及裸鼠致瘤性。流式细胞术检测阿霉素在亲本及耐药细胞株内的积聚量。免疫细胞化学法检测胸苷酸合酶在耐药细胞内的表达。结果:成功建立人肝癌BEL-7402/5-FU多药耐药细胞株模型。该耐药细胞对阿霉素、长春新碱、奥沙利铂及甲氨蝶呤均有不同程度的交叉耐药性,但对羟基喜树碱仍较敏感。体外培养见细胞趋向群集性生长。耐药细胞株倍增时间较亲本细胞株长,克隆形成率则较亲本细胞株低,差异有统计学意义。耐药细胞贴壁率在23、h明显低于亲本细胞株,其G0/G1期细胞分布比率较低而S期比率明显增加。阿霉素在耐药细胞株内的积聚量低于亲本细胞株,耐药细胞株胸苷酸合酶的蛋白表达量较亲本细胞株明显增强。结论:人肝癌BEL-7402/5-FU多药耐药细胞株可以成为研究5-FU获得性耐药机制及开展多药耐药逆转剂筛选较好的体外模型。

人肝癌多药耐药细胞株survivin蛋白的表达及意义

目的 探讨人肝癌多药耐药细胞株survivin蛋白表达与肝癌细胞多药耐药的关系。方法 用阿霉素(DOX)浓度梯度递增诱导法,建立人肝癌多药耐药细胞株(Bel- 74 0 2 / DOX)。用流式细胞仪检测肝癌细胞凋亡率,同时用蛋白印迹(Western blot)检测其survivin蛋白表达。结果 随着培养液中DOX浓度的增加,Bel- 74 0 2 /DOX的凋亡率逐渐增加,survivin蛋白的表达逐渐增强。结论 Survivin蛋白的表达变化可能与人肝癌细胞获得性耐药有关。