To develop a new method of inducing mdrl multidrug resistance by establishinga nude mice model of orthotopic transplantation of liver carcinoma by sporadic abdominalchemotherapy at intervals. Methods: Hepatocellular c...To develop a new method of inducing mdrl multidrug resistance by establishinga nude mice model of orthotopic transplantation of liver carcinoma by sporadic abdominalchemotherapy at intervals. Methods: Hepatocellular carcinoma HepG2 cell was cultured and injectedsubcutaneously to form the tumor-supplying mice. The tumor bits from the tumor-supplying mice wereimplanted under the envelope of the mice liver and induced by abdominal chemotherapy withPharmorubicin. Physical examination, ultrasonography, spiral CT and operative inspection were usedto examine tumor progression. RT-PCR and immunohistochemistry were adopted to detect the expressionof mdr1-mRNA and its encoded protein P-gp protein (P-gp). Results: There was no operative dead, therate of implanting tumor successfully was 88% (22/25), the rate of implanting secondly successfullywas 100% (3/3), and the rate of inducing successfully was 80% (16/20). The expression of mdrl-mRNAand the P-gp in the inducing group was 23 folds and 13 folds in the control group respectively.Conclusion: We have established an in vivo model of mdr using nude mice transplanted with orthotopicliver neoplasm coupled to chemotherapy.展开更多
The distribution of ￣(3)H-mitoxantrone polybutyl cyanoacrylate nanospheres(￣(3)H-DHAQ-PBCA-NS)in the viscera,muscle and tumors of human hepatocellular carcinoma (HCC)model in nude mice was studied with liquid scinti...The distribution of ￣(3)H-mitoxantrone polybutyl cyanoacrylate nanospheres(￣(3)H-DHAQ-PBCA-NS)in the viscera,muscle and tumors of human hepatocellular carcinoma (HCC)model in nude mice was studied with liquid scintillation counting techniique. The results showed that the ￣(3)H-DHAQ-PBCA-NS had remarkable liver targeting effect. The content of ￣(3)H-DHAQ-PBCA-NSin liver and heterotopic liver tumor was found to be 71.31±10. 49% of total amount of drug in animal body. It was also found that the content of ￣(3)H-DHAQ-PBCA-NS in liver was higher than that in liver tissue, and the content of ￣(3)H-DHAQ-PBCA-NS in annpit tumor was higher than that in armpit muscle tissue,but had no significant difference;It provides an ideal preparation for the DHAQ admini-stration.展开更多
In the present study, a simple, rapid, and sensitive liquid chromatography-tandem mass spectrometric method for the determination of axitinib in nude mouse plasma was developed, validated, and applied to a pharmacokin...In the present study, a simple, rapid, and sensitive liquid chromatography-tandem mass spectrometric method for the determination of axitinib in nude mouse plasma was developed, validated, and applied to a pharmacokinetic study. Plasma samples were pre-treated by protein precipitation with acetonitrile spiked with erlotinib as an internal standard. The chromatographic separation was accomplished by using a reversed phase C18 column （50 mm×2 mm, 5 μm） with a simple mobile phase system composed of methanol and water （60：40, v/v） at an isocratic flow rate of 0.4 mL/min. The analyte was detected by a triple-quadrupole tandem mass spectrometer via electrospray ionization and multiple reaction monitoring was employed to select both axitinib and erlotinib in the positive ion mode. The calibration curves were linear （r〉0.99） ranging from 1 to 1000 ng/mL, and the lowest level of this range was the lower limit of quantification. The intra- and inter-day precision were 7.7%-12.0%, and the accuracies ranged from 88.6% to 110.4%. This method was successfully applied to a preclinical pharmacokinetic study on female nu/nu nude mice administrated with a single oral dose of axitinib at 120 mg/kg, and the pharmacokinetics was characterized by a one-compartment model with first-order absorption.展开更多
A simple, rapid and sensitive LC-MS/MS method was developed to quantify erlotinib and its active metabolite, OSI-420, simultaneously in BALB/c nude mice plasma. Erlotinib, OSI-420 and propranolol （internal standard）...A simple, rapid and sensitive LC-MS/MS method was developed to quantify erlotinib and its active metabolite, OSI-420, simultaneously in BALB/c nude mice plasma. Erlotinib, OSI-420 and propranolol （internal standard） were extracted from nude mice plasma samples by liquid-liquid extraction. Separation was achieved on a reversed phase ClS column with a mobile phase of acetonitrile-water （35：65, v/v） containing 5 mM ammonium formate （pH = 3.0）. All compounds were monitored by mass spectrometry with electrospray positive ionization. The lower limit of quantification was 0.5 ng/mL for both erlotinib and OSI-420; accuracy was estimated by relative error, which was in the range from 0.07% to 8.00% for erlotinib and -2.83% to 6.67% for OSI-420; precision was validated by relative standard deviation, which was from 2.28% to 15.12% for erlotinib and from 1.96% to 11.50% for OSI-420. This method was applied to a pharmacokinetic study of BALB/c nude mice following oral administration of erlotinib at 12.5 mg/kg. A 2-compartment model was used to fit the pharmacokinetics of erlotinib and 1-compartment model for the pharmacokinetics of OSI-420. The ratio of the active metabolite to parent drug in mice was greater than previously reported in humans and probably reflects interspecies difference in the rate of conversion of erlotinib to OSI-420.展开更多
A sensitive, rapid, and simple liquid chromatography tandem mass spectrometry（LC-MS/MS） method for simultaneous determination of sunitinib and its active metabolites in plasma of BABL/c nude mice was developed and v...A sensitive, rapid, and simple liquid chromatography tandem mass spectrometry（LC-MS/MS） method for simultaneous determination of sunitinib and its active metabolites in plasma of BABL/c nude mice was developed and validated. Plasma samples were pre-treated by protein precipitation with pazopanib and used as an internal standard. Separation was performed on a reversed phase C18 column with a mobile phase composing of 10 m M ammonium formate p H 3.25（adjusted with formic acid） and acetonitrile（65：35, v/v） at a flow rate of 0.5 mL /min. Triple quadrupole tandem mass in multiple reaction monitoring（MRM） mode with electrospray positive ionization was used to monitor all the compounds. The current LC-MS/MS method was highly selective and sensitive with lowest limit of quantitation（LLOQ） of 0.5 ng/mL for both analytes and reliable intra- and inter-day precision and accuracy validated by relative error（RE%） and relative standard deviation（RSD%）. Linearity of calibration curve was excellent（r0.99） within a concentration range of 0.5–1000 ng/mL. This method was successfully applied to a pharmacokinetics study on BABL/c nude mice given with single dose of oral administration of sunitinib at 20 mg/kg.展开更多
AIM To investigate the effects of taxol onSMMC-7721 human hepatoma and itsmechanisms.METHODS In vitro cell growth was assessedby trypan blue exclusion method.Experimentalhepatoma model was established by seedingSMMC-7...AIM To investigate the effects of taxol onSMMC-7721 human hepatoma and itsmechanisms.METHODS In vitro cell growth was assessedby trypan blue exclusion method.Experimentalhepatoma model was established by seedingSMMC-7721 cells subcutaneously into Balb/c(nu/nu)nude mice.In vivo tumor growth wasdetermined by measurement of tumor diameterwith Vernier calipers.The syntheses of DNA,RNA and protein were analyzed by incorporationof ~3H-thymidine,~3H-uridine and ~3H-leucinerespectively.Using light and electronmicroscopes to observe the morphologicalchanges of cells including mitosis andapoptosis.RESULTS Taxol was effective against SMMC-7721 human hepatoma cell growth in the rangesof 2.5 nmol/L-10 nmol/L with mitotic arrestand apoptosis in vitro.DNA,RNA and proteinsyntheses in cells were also obviouslysuppressed by in vitro treatment of taxol for72 h.Taxol at 2.5 nmol/L reduced ~3H-thymidineuptake to about 34% of the control value(P【0.05).Increasing the dose of taxol to20 nmol/L resulted in a greater decrease in ~3H-thymidine incorporation to 60% of the controlvalue(P【0.01).At a concentration of 20 nmol/L,the ~3H-uridine and ~3H-leucine uptakeswere reduced to 52%(P【0.05)and 63%(P【0.01),respectively.In vivo,taxolsignificantly inhibited SMMC-7721 tumor growthat 10 mg/kg,i.p.,once daily for 10 d.A morethan 90% decrease in tumor volume wasobserved by day 11(P【0.01)similarly withmitotic arrest and cell apoptosis.CONCLUSION Taxol has a marked anticanceractivity in SMMC-7721 human hepatoma both invitro and in nude mice.Its mechanisms might beassociated with mitotic arrest,subsequently,apoptosis of the hepatoma cells.No obvioustoxicity was observed with in vivoadministration of taxoi.展开更多
Metastatic human HCC model is needed for the studies on mechanism and intervention of metastatic recurrence. By using orthotopic implantation of histologically intact tissues of 30 surgical specimens, a patient-like m...Metastatic human HCC model is needed for the studies on mechanism and intervention of metastatic recurrence. By using orthotopic implantation of histologically intact tissues of 30 surgical specimens, a patient-like metastatic model of human HCC in nude mice (LCI-D20) and a low metastatic model of human HCC in nude mice (LCI-D35) have been established. All mice with transplanted LCI-D20 tumors exhibited extremely high metastatic ability including spontaneous metastasis to liver, lungs, lymph nodes and peritoneal seeding. Remarkable difference was also found in expression of some of the invasiveness related genes and growth factors between the LCI-D20 and LCI-D35 tumors. PAI-1 increased gradually following tumor progression in LCI-D20 model, and correlated with tumor size and AFP level. Phasic expression of tissue intercellular adhesion molecule-1 in this model was also observed. Using corneal micropocket model, it was demonstrated that the vascular response induced by LCI-D20 tumor was stronger than that induced by LCI-D35 tumor. Similar report on metastatic human HCC model in nude mice and human HCC cell line with metastatic potential was rarely found in the literature. This LCI-D20 model has been widely used for the studies on intervention of metastasis, including anti-angiogenesis,antisense approach, metalloproteinase inhibitor, differentiation inducer, etc. It is concluded that the establishment of metastatic human HCC model in nude mice and human HCC cell line with metastatic potential will provide important models for the in vitro and in vitro study of HCC invasiveness, angiogenesis as well as intervention of HCC recurrence.展开更多
AIM: To investigate anti-tumor activities and apoptosis-regulated mechanisms of bufalin in the orthotopic transplantation tumor model of human hepatocellular carcinoma in nude mice.METHODS: BEL-7402 cells of human hep...AIM: To investigate anti-tumor activities and apoptosis-regulated mechanisms of bufalin in the orthotopic transplantation tumor model of human hepatocellular carcinoma in nude mice.METHODS: BEL-7402 cells of human hepatocellular carcinoma were inoculated to form subcutaneous tumors, and were implanted into the liver to establish orthotopic transplantation tumor models of human hepatocellular carcinoma in nude mice. Seventy-five animals were randomized divided into five groups (n = 15). Bufalin was injected intraperitoneally into three groups at doses of 1.5 mg/kg (BF1), 1 mg/kg (BF2) and 0.5 mg/kg (BF3) for d 15-24, respectively. The NS group was injected an equal volume of saline as above and adriamycin was injected intraperitoneally into the ADM group at a dose of 8.0 mg/kg for d 15. Ten mice in each group were killed at d 25 and the survival time in each group was calculated. We also observed the morphologic alterations in the myocardium, brain, liver, kidney and tumor tissues by pathology and electron microscopy, measured the apoptotic rate by TUNEL staining method, and detected the expression of apoptosis-regulated genes bcl-2 and bax by immunohistochemical staining and RT-PCR in tumor tissues. RESULTS: The tumor volumes in each group of bufalin were reduced significantly (35.21 ± 12.51 vs 170.39 ± 25.29; 49.83 ± 11.46 vs 170.39 ± 25.29; 83.99 ± 24.63 vs 170.39 ± 25.29, P < 0.01, respectively), and the survival times were prolonged in group BF1-2 (31.8 ± 4.2 vs 23.4 ± 2.1 and 29.4 ± 3.4 vs 23.4 ± 2.1, P < 0.05, respectively), and necrosis was mainly in severe or moderate degree in group BF1-2. No morphologicalchanges were detected in the myocardium, brain, liver and kidney tissues. Apoptotic characteristics could be seen in group BF1-2. The positive rates of bcl-2 and bax protein expression of each group by immunohistochemical staining were 10.0%, 10.0%, 20.0%, 10.0% and 20.0%; 90.0%, 80.0%, 80.0%, 40.0% and 30.0%, respectively. Loss of expression of bcl-2 mRNA in each group was to be found and the density of bax mRNA was increased progressively with increase of dose of bufalin by RT-PCR. CONCLUSION: Bufalin has significant anti-tumor activities in the orthotopic transplantation tumor model of human hepatocellular carcinoma in nude mice with no marked toxicity and was able to induce apoptosis of transplanted tumor cells. This apoptosis may be mediated mainly via up-regulating the expression of apoptosis-regulated gene bax, which may be involved in its anti-tumor mechanism of bufalin.展开更多
In the current study, we established and validated a simple and sensitive liquid chromatography-tandem mass spectrometric method for the determination of 21-hydroxy deflazacort in nude mice plasma, and such a method w...In the current study, we established and validated a simple and sensitive liquid chromatography-tandem mass spectrometric method for the determination of 21-hydroxy deflazacort in nude mice plasma, and such a method was applied to a pharmacokinetic study. Using betamethasone as the internal standard, the plasma samples were pre-treated by precipitation with acetonitrile and then analyzed on a reversed-phase C18 column （50 mm×2 mm, 5 μm） with a mobile phase consisting of acetonitrile and 4.0 mM ammonium formate （pH was adjusted to 3.5 with formic acid （40：60, v/v））. The analyte was detected by a triple quadrupole tandem mass spectrometer using electrospray, and multiple reaction monitoring was employed to select 21-hydroxy deflazacort at m/z 400.2/124.0 and betamethasone at m/z 393.3/147.0 in the positive ion mode. The calibration curves were linear （r〉0.99） over the range of 0.5~,00 ng/mL. The intra- and inter-day precisions and accuracies were 4.5%-10.1% and -1.7%-10.7% respectively. This method was successfully applied to a preclinical administered with a single oral dose of 4 mg/kg deflazacort, and its pharmacokinetic study of deflazacort on female nude mice pharmacokinetics was characterized by a two-compartment model with first-order absorption.展开更多
AIM To establish a method of labeling anti hepatoma McAb (HAb18) Fab fragment modifier with 99m Tc. METHODS HAb18 Fab was modified with 2 iminotholane and labeled with 99m Tc by transchelation f...AIM To establish a method of labeling anti hepatoma McAb (HAb18) Fab fragment modifier with 99m Tc. METHODS HAb18 Fab was modified with 2 iminotholane and labeled with 99m Tc by transchelation from 99m Tc GH. Labeling yield, radiochemical purity and immunoreactivity were determined by thin layer chromatography (TLC SG), paper chromatography (PC), gel chromatography (GC) and cell binding assay, respectively. The nude mice bearing human hepatoma were used for radioimmunoimaging (RII). RESULTS A radiolabeling yield of 50%-80% was obtained, and immunoreactivity (IR) was 30%-40%. Radioimaging results showed that 99m Tc HAb18 McAb Fab fragment was concentrated in the tumor 4-8 hours after injection, and the maximum concentration was seen in 12-24 hours, and the T/NT value was 5 18 and 7 48 at 6h and 8h after the injection. CONCLUSION 99m Tc HAb18 McAb Fab fragment could be specifically localized in the tumor of nude mice bearing human hepatocellular carcinoma within 24 hours and this method might be effectively used for labeling McAb Fab fragment with展开更多
AIM： To establish nude mouse human gastric cancer orthotopic transplantation models using OB glue paste technique. METHODS： Using OB glue paste technique, orthtopic transplantation models were established by implant...AIM： To establish nude mouse human gastric cancer orthotopic transplantation models using OB glue paste technique. METHODS： Using OB glue paste technique, orthtopic transplantation models were established by implanting SGC-7901 and NKN-45 human gastric cancer cell strains into the gastric wall of nude mice. Biological features, growth of the implanted tumors, the success rate of transplantation and the rate of auto-metastasis of the two models were observed. RESULTS： The success rates of orthotopic transplanration of the two models were 94.20% and 96%. The rates of hepatic metastasis, pulmonary metastasis, peritoneal metastasis, lymphocytic metastasis and splenic metastasis were 42.13% and 94.20%, 48.43% and 57.97%, 30.83% and 36.96%, 67.30% and 84.06%, and 59.75% and 10.53%, respectively. The occurrence of ascites was 47.80% and 36.96%. CONCLUSION： OB glue paste technique is easy to follow. The biological behaviors of the nude mouse human gastric cancer orthotopic transplantation models established with this technique are similar to the natural processes of growth and metastasis of human gastric cancer, and, therefore, can be used as an ideal model for experimental research of proliferative metastasis of tumors.展开更多
AIM:To investigate the change in expression of p53 ,Bcl-2 ,and Bax genes in human colon cancer cells transplanted into nude mice after hyperthermia,chemotherapy,radiotherapy,thermochemotherapy,thermoradiotherapy and t...AIM:To investigate the change in expression of p53 ,Bcl-2 ,and Bax genes in human colon cancer cells transplanted into nude mice after hyperthermia,chemotherapy,radiotherapy,thermochemotherapy,thermoradiotherapy and thermochemoradiotherapy. METHODS:Human colon cancer cell line (HT29) was transplanted into the hind limbs of nude mice. Under laboratory simulated conditions of hyperthermia (43℃,60 min),the actual radiation doses and doses of mitomycin C (MMC) were calculated in reference to the clinical radiotherapy for human rectal cancer and chemotherapy prescription for colon cancer. The mice were divided into 6 groups according to the treatment approaches:hyperthermia,chemotherapy,radiotherapy,thermochemotherapy,thermoradiotherapy,and thermochemoradiotherapy. The mice were sacrificed at different time points and the tumor tissue was taken for further procedures. The morphologic changes in membrane,cytoplasm and nuclei of tumor cells of p53,Bcl-2,and Bax after treatment,were observed by immunohistochemistry staining. RESULTS:All of the six treatment modalities down-regulated the expression of p53,Bcl-2 and up-regulated the expression of Bax at different levels. The combined therapy of hyperthermia,with chemotherapy,and/or irradiation showed a greater effect on down-regulating the expression of p53 (0.208 ± 0.009 vs 0.155 ± 0.0115,P < 0.01) and Bcl-2 (0.086 ± 0.010 vs 0.026 ± 0.0170,P < 0.01) and up-regulating Bax expression (0.091 ± 0.0013 vs 0.207 ± 0.027,P < 0.01) compared with any single therapy.CONCLUSION:Hyperthermia enhances the effect of radio-and chemotherapy on tumors by changing the expression of apoptosis genes,such as p53,Bcl-2 and Bax.展开更多
BACKGROUND: Targeting is a new therapeutic tool for malignant tumor as a result of combining nanotechnology with chemotherapeutics. The aim of our study was to investigate the effects of magnetic nanoparticles envelop...BACKGROUND: Targeting is a new therapeutic tool for malignant tumor as a result of combining nanotechnology with chemotherapeutics. The aim of our study was to investigate the effects of magnetic nanoparticles enveloping a chemotherapeutic drug on human cholangiocarcinoma xenografts in nude mice. METHODS: The human cholangiocarcinoma xenograft model was established in nude mice with the QBC939 cell line. The nude mice were randomly assigned to 7 groups. 0.9% saline or magnetic nanoparticles, including high (group 2), medium (group 4) and low (group 5) dosages, were given to nude mice through the tail vein 20 days after the QBC939 cell line was implanted. Calculations were made 35 days after treatment in order to compare the volumes, inhibition ratios and growth curves of the tumors in each group. Mice in each group were sacrificed randomly to collect tumor tissues and other organs for electron microscopy and pathological examination. RESULTS: The high and medium dosage groups were significantly different from the control group (P<0.05). The tumor inhibition ratios for the high, medium and low dosage groups were 39.6%, 14.6% and 7.9%, respectively. The tumor growth curve of groups 5, 4, and 2 changed slowly in turn. The high and medium groups showed cell apoptosis under an electron microscope. CONCLUSION: Magnetic nanoparticles can inhibit the growth of human cholangiocarcinoma xenografts in nude mice.展开更多
Purpose： The objective of this study was to investigate the anti-tumor effects and analyze the mechanism of artesunate （ART） action on breast cancer in vivo using tumor transplanted nude mice. Methods： The human b...Purpose： The objective of this study was to investigate the anti-tumor effects and analyze the mechanism of artesunate （ART） action on breast cancer in vivo using tumor transplanted nude mice. Methods： The human breast tumor cell line MCF-7 was transplanted into nude mice, and the animals were treated with various doses of ART alone or in combination with cyclophosphamide （CTX） or normal saline （NS）. The tumor inhibitory effects were observed and compared, and the ultrastructural morphology of the transplanted tumor cells was observed by electron microscopy. The apoptosis rates and cell cycle status were detected by flow cytometry （FCM）. The expression of apoptosis-related proteins p53, Bcl-2, Bax and Caspase-3 were detected by immunohistochemistry and IGF-IR was detected by western blot. The expression correlation for these proteins was also analyzed. Results： The tumor inhibition rates in the low dose ART group, high dose ART group, CTX group and combined drug therapy group were （24.39±10.20）%, （40.24±7.02）%, （57.01±5.84）% and （68.29±5.1）%, respectively. The cell cycle was arrested in phase G0/Gt after treatment with ART. The expression of Bcl-2 was significantly reduced, and the expression levels of Bax and Caspase-3 were significantly increased in the ART group compared to the negative control saline group. There was no significant difference detected in p53 expression. The Bcl-2 level was negatively related to Bax and Caspase-3. The western blotting results showed IGF-IR downregulation. Conclusions： ART inhibits the growth of MCF-7 breast tumor cell xenografts in nude mice. The anti-tumor mechanism of ART for human breast carcinoma in nude mice might be correlated with the alteration of apoptosis related protein expression, which may further induce apoptosis and inhibit cell proliferation.展开更多
AIM： To explore the effect of silencing of signal transducer and activator of transcription 3 （STAT3） expression by RNA interference （RNAi） on growth of human hepatocellular carcinoma （HCC） in tumorbearing nude...AIM： To explore the effect of silencing of signal transducer and activator of transcription 3 （STAT3） expression by RNA interference （RNAi） on growth of human hepatocellular carcinoma （HCC） in tumorbearing nude mice in vivo.METHODS： To construct the recombinant plasmid of pSilencer 3.0-H1-STAT3-siRNA-GFP （pSHI-siRNA- STAT3） and establish the tumor-bearing nude mouse model of the HCC cell line SMMC7721, we used intratumoral injection together with electroblotting to transfect the recombinant plasmid pSHI-siRNA- STAT3 into the transplanted tumor. The weight of the nude mice and tumor volumes were recorded. STAT3 gene transcription was detected by semi-quantitative reverse transcription polymerase chain reaction （RT- PCR）. Level of protein expression and location of STAT3 were determined by Western blotting and immunohistochemical staining. STAT3-related genes such as survivin, c-myc, VEGF, p53 and caspase3 mRNA and protein expression were detected in tumor tissues at the same time. The terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling （TUNEL） assay was used to detect apoptosis of tumor cells.RESULTS： The weight of the treated nude mice increased, and the tumor volume decreased markedly compared with those of the mock-treated and negative control groups （P 〈 0.01）. The results of RT-PCR and Western blotting showed that mRNA and protein levels of STAT3 declined markedly in the treated group. The change in STAT3-related gene expression in tumor tissues at the mRNA and protein level also varied, the expression of survivin, VEGF and c-myc were obviously reduced, and expression of p53 and caspase3 increased （P 〈 0.01）. Most of the tumor tissue ceils in the treated group developed apoptosis that was detected by TUNEL assay.CONCLUSION： Silencing of STAT3 expression by RNAi significantly inhibits expression of STAT3 mRNA and protein, and suppresses growth of human HCC in tumor-bearing nude mice. The mechanism may be related to down-regulation of survivin, VEGF and c-myc and up-regulation of p53 and caspase3 expression. Accordingly, the STAT3 gene may act as an important and effective target in gene therapy of HCC.展开更多
AIM： To establish a multidrug resistant （MDR） cell subline from the human hepatocardnoma cell line （HepG2） in nude mice. METHODS： HepG2 cell cultures were incubated with increasing concentrations of adriamycin ...AIM： To establish a multidrug resistant （MDR） cell subline from the human hepatocardnoma cell line （HepG2） in nude mice. METHODS： HepG2 cell cultures were incubated with increasing concentrations of adriamycin （ADM） to develop an ADM-resistant cell subline （HepG2/ADM） with crossresistance to other chemotherapeutic agents. Twenty male athymic BALB/c-nu/nu mice were randomized into HepG2/nude and HepG2/ADM/nude groups （10 in each group）. A cell suspension （either HepG2 or HepG2/ADM） was injected subcutaneously into mice in each group. Tumor growth was recorded, and animals were sacrificed 4-5 wk after cell implantation. Tumors were prepared for histology, and viable tumor was dispersed into a single-cell suspension. The IC50 values for a number of chemotherapeutic agents were determined by 2, 3-bis （2-methoxy-4-nitro-5-sulfophenyl）-2H-tetrazolium-5-carboxanilide inner salt （MTT） assay. Rhodamine-123 retention/efflux and the level of resistance-associated proteins were determined by flow cytometry. The mRNA expression of mdr1, mrp and Irp genes was detected using reverse transcriptase polymerase chain reaction （RT-PCR） in HepG2/nude and HepG2/ADM/nude groups. RESULTS： The appearances of HepG2/nude cells were slightly different from those of HepG2/ADM/nude cells. Similar tumor growth curves were determined in both groups. A cross-resistance to ADM, vincristine, cisplatin and 5-fluorouracil was seen in HepG2/ADM/nude group. The levels of P-glycoprotein and multidrug resistanceassociated proteins were significantly increased. The mRNA expression levels of mdrl, mrp and/rp were higher in HepG2/ADM/nude cells. CONCLUSION： ADM-resistant HepG2 subline in nude mice has a cross resistance to chemotherapeutic drugs. It may be used as an in vivo model to investigate the mechanisms of MDR, and explore the targeted approaches to overcoming MDR.展开更多
基金This project was supported by a grant from the Medical Science and Technique Foundation of Ministry of Health of China(No. Wkz-2000-1-15).
文摘To develop a new method of inducing mdrl multidrug resistance by establishinga nude mice model of orthotopic transplantation of liver carcinoma by sporadic abdominalchemotherapy at intervals. Methods: Hepatocellular carcinoma HepG2 cell was cultured and injectedsubcutaneously to form the tumor-supplying mice. The tumor bits from the tumor-supplying mice wereimplanted under the envelope of the mice liver and induced by abdominal chemotherapy withPharmorubicin. Physical examination, ultrasonography, spiral CT and operative inspection were usedto examine tumor progression. RT-PCR and immunohistochemistry were adopted to detect the expressionof mdr1-mRNA and its encoded protein P-gp protein (P-gp). Results: There was no operative dead, therate of implanting tumor successfully was 88% (22/25), the rate of implanting secondly successfullywas 100% (3/3), and the rate of inducing successfully was 80% (16/20). The expression of mdrl-mRNAand the P-gp in the inducing group was 23 folds and 13 folds in the control group respectively.Conclusion: We have established an in vivo model of mdr using nude mice transplanted with orthotopicliver neoplasm coupled to chemotherapy.
文摘The distribution of ￣(3)H-mitoxantrone polybutyl cyanoacrylate nanospheres(￣(3)H-DHAQ-PBCA-NS)in the viscera,muscle and tumors of human hepatocellular carcinoma (HCC)model in nude mice was studied with liquid scintillation counting techniique. The results showed that the ￣(3)H-DHAQ-PBCA-NS had remarkable liver targeting effect. The content of ￣(3)H-DHAQ-PBCA-NSin liver and heterotopic liver tumor was found to be 71.31±10. 49% of total amount of drug in animal body. It was also found that the content of ￣(3)H-DHAQ-PBCA-NS in liver was higher than that in liver tissue, and the content of ￣(3)H-DHAQ-PBCA-NS in annpit tumor was higher than that in armpit muscle tissue,but had no significant difference;It provides an ideal preparation for the DHAQ admini-stration.
基金National Natural Science Foundation of China(NSFC,Grant No.81473277)
文摘In the present study, a simple, rapid, and sensitive liquid chromatography-tandem mass spectrometric method for the determination of axitinib in nude mouse plasma was developed, validated, and applied to a pharmacokinetic study. Plasma samples were pre-treated by protein precipitation with acetonitrile spiked with erlotinib as an internal standard. The chromatographic separation was accomplished by using a reversed phase C18 column （50 mm×2 mm, 5 μm） with a simple mobile phase system composed of methanol and water （60：40, v/v） at an isocratic flow rate of 0.4 mL/min. The analyte was detected by a triple-quadrupole tandem mass spectrometer via electrospray ionization and multiple reaction monitoring was employed to select both axitinib and erlotinib in the positive ion mode. The calibration curves were linear （r〉0.99） ranging from 1 to 1000 ng/mL, and the lowest level of this range was the lower limit of quantification. The intra- and inter-day precision were 7.7%-12.0%, and the accuracies ranged from 88.6% to 110.4%. This method was successfully applied to a preclinical pharmacokinetic study on female nu/nu nude mice administrated with a single oral dose of axitinib at 120 mg/kg, and the pharmacokinetics was characterized by a one-compartment model with first-order absorption.
基金National Integrity Innovational Technology Platform of New Drug and Development (Grant No. 2009ZX09301-010)Innovation Team of Ministry of Education (Grant No. BMU20110263)
文摘A simple, rapid and sensitive LC-MS/MS method was developed to quantify erlotinib and its active metabolite, OSI-420, simultaneously in BALB/c nude mice plasma. Erlotinib, OSI-420 and propranolol （internal standard） were extracted from nude mice plasma samples by liquid-liquid extraction. Separation was achieved on a reversed phase ClS column with a mobile phase of acetonitrile-water （35：65, v/v） containing 5 mM ammonium formate （pH = 3.0）. All compounds were monitored by mass spectrometry with electrospray positive ionization. The lower limit of quantification was 0.5 ng/mL for both erlotinib and OSI-420; accuracy was estimated by relative error, which was in the range from 0.07% to 8.00% for erlotinib and -2.83% to 6.67% for OSI-420; precision was validated by relative standard deviation, which was from 2.28% to 15.12% for erlotinib and from 1.96% to 11.50% for OSI-420. This method was applied to a pharmacokinetic study of BALB/c nude mice following oral administration of erlotinib at 12.5 mg/kg. A 2-compartment model was used to fit the pharmacokinetics of erlotinib and 1-compartment model for the pharmacokinetics of OSI-420. The ratio of the active metabolite to parent drug in mice was greater than previously reported in humans and probably reflects interspecies difference in the rate of conversion of erlotinib to OSI-420.
基金National Natural Science Foundation of China(NSFC,Grant No.81473277)
文摘A sensitive, rapid, and simple liquid chromatography tandem mass spectrometry（LC-MS/MS） method for simultaneous determination of sunitinib and its active metabolites in plasma of BABL/c nude mice was developed and validated. Plasma samples were pre-treated by protein precipitation with pazopanib and used as an internal standard. Separation was performed on a reversed phase C18 column with a mobile phase composing of 10 m M ammonium formate p H 3.25（adjusted with formic acid） and acetonitrile（65：35, v/v） at a flow rate of 0.5 mL /min. Triple quadrupole tandem mass in multiple reaction monitoring（MRM） mode with electrospray positive ionization was used to monitor all the compounds. The current LC-MS/MS method was highly selective and sensitive with lowest limit of quantitation（LLOQ） of 0.5 ng/mL for both analytes and reliable intra- and inter-day precision and accuracy validated by relative error（RE%） and relative standard deviation（RSD%）. Linearity of calibration curve was excellent（r0.99） within a concentration range of 0.5–1000 ng/mL. This method was successfully applied to a pharmacokinetics study on BABL/c nude mice given with single dose of oral administration of sunitinib at 20 mg/kg.
文摘AIM To investigate the effects of taxol onSMMC-7721 human hepatoma and itsmechanisms.METHODS In vitro cell growth was assessedby trypan blue exclusion method.Experimentalhepatoma model was established by seedingSMMC-7721 cells subcutaneously into Balb/c(nu/nu)nude mice.In vivo tumor growth wasdetermined by measurement of tumor diameterwith Vernier calipers.The syntheses of DNA,RNA and protein were analyzed by incorporationof ~3H-thymidine,~3H-uridine and ~3H-leucinerespectively.Using light and electronmicroscopes to observe the morphologicalchanges of cells including mitosis andapoptosis.RESULTS Taxol was effective against SMMC-7721 human hepatoma cell growth in the rangesof 2.5 nmol/L-10 nmol/L with mitotic arrestand apoptosis in vitro.DNA,RNA and proteinsyntheses in cells were also obviouslysuppressed by in vitro treatment of taxol for72 h.Taxol at 2.5 nmol/L reduced ~3H-thymidineuptake to about 34% of the control value(P【0.05).Increasing the dose of taxol to20 nmol/L resulted in a greater decrease in ~3H-thymidine incorporation to 60% of the controlvalue(P【0.01).At a concentration of 20 nmol/L,the ~3H-uridine and ~3H-leucine uptakeswere reduced to 52%(P【0.05)and 63%(P【0.01),respectively.In vivo,taxolsignificantly inhibited SMMC-7721 tumor growthat 10 mg/kg,i.p.,once daily for 10 d.A morethan 90% decrease in tumor volume wasobserved by day 11(P【0.01)similarly withmitotic arrest and cell apoptosis.CONCLUSION Taxol has a marked anticanceractivity in SMMC-7721 human hepatoma both invitro and in nude mice.Its mechanisms might beassociated with mitotic arrest,subsequently,apoptosis of the hepatoma cells.No obvioustoxicity was observed with in vivoadministration of taxoi.
基金Partly supporled by the State Key Basic Research Program Grant of China(G1998051211)Leading Speciality Grant of Shanghai Health Bureau.
文摘Metastatic human HCC model is needed for the studies on mechanism and intervention of metastatic recurrence. By using orthotopic implantation of histologically intact tissues of 30 surgical specimens, a patient-like metastatic model of human HCC in nude mice (LCI-D20) and a low metastatic model of human HCC in nude mice (LCI-D35) have been established. All mice with transplanted LCI-D20 tumors exhibited extremely high metastatic ability including spontaneous metastasis to liver, lungs, lymph nodes and peritoneal seeding. Remarkable difference was also found in expression of some of the invasiveness related genes and growth factors between the LCI-D20 and LCI-D35 tumors. PAI-1 increased gradually following tumor progression in LCI-D20 model, and correlated with tumor size and AFP level. Phasic expression of tissue intercellular adhesion molecule-1 in this model was also observed. Using corneal micropocket model, it was demonstrated that the vascular response induced by LCI-D20 tumor was stronger than that induced by LCI-D35 tumor. Similar report on metastatic human HCC model in nude mice and human HCC cell line with metastatic potential was rarely found in the literature. This LCI-D20 model has been widely used for the studies on intervention of metastasis, including anti-angiogenesis,antisense approach, metalloproteinase inhibitor, differentiation inducer, etc. It is concluded that the establishment of metastatic human HCC model in nude mice and human HCC cell line with metastatic potential will provide important models for the in vitro and in vitro study of HCC invasiveness, angiogenesis as well as intervention of HCC recurrence.
文摘AIM: To investigate anti-tumor activities and apoptosis-regulated mechanisms of bufalin in the orthotopic transplantation tumor model of human hepatocellular carcinoma in nude mice.METHODS: BEL-7402 cells of human hepatocellular carcinoma were inoculated to form subcutaneous tumors, and were implanted into the liver to establish orthotopic transplantation tumor models of human hepatocellular carcinoma in nude mice. Seventy-five animals were randomized divided into five groups (n = 15). Bufalin was injected intraperitoneally into three groups at doses of 1.5 mg/kg (BF1), 1 mg/kg (BF2) and 0.5 mg/kg (BF3) for d 15-24, respectively. The NS group was injected an equal volume of saline as above and adriamycin was injected intraperitoneally into the ADM group at a dose of 8.0 mg/kg for d 15. Ten mice in each group were killed at d 25 and the survival time in each group was calculated. We also observed the morphologic alterations in the myocardium, brain, liver, kidney and tumor tissues by pathology and electron microscopy, measured the apoptotic rate by TUNEL staining method, and detected the expression of apoptosis-regulated genes bcl-2 and bax by immunohistochemical staining and RT-PCR in tumor tissues. RESULTS: The tumor volumes in each group of bufalin were reduced significantly (35.21 ± 12.51 vs 170.39 ± 25.29; 49.83 ± 11.46 vs 170.39 ± 25.29; 83.99 ± 24.63 vs 170.39 ± 25.29, P < 0.01, respectively), and the survival times were prolonged in group BF1-2 (31.8 ± 4.2 vs 23.4 ± 2.1 and 29.4 ± 3.4 vs 23.4 ± 2.1, P < 0.05, respectively), and necrosis was mainly in severe or moderate degree in group BF1-2. No morphologicalchanges were detected in the myocardium, brain, liver and kidney tissues. Apoptotic characteristics could be seen in group BF1-2. The positive rates of bcl-2 and bax protein expression of each group by immunohistochemical staining were 10.0%, 10.0%, 20.0%, 10.0% and 20.0%; 90.0%, 80.0%, 80.0%, 40.0% and 30.0%, respectively. Loss of expression of bcl-2 mRNA in each group was to be found and the density of bax mRNA was increased progressively with increase of dose of bufalin by RT-PCR. CONCLUSION: Bufalin has significant anti-tumor activities in the orthotopic transplantation tumor model of human hepatocellular carcinoma in nude mice with no marked toxicity and was able to induce apoptosis of transplanted tumor cells. This apoptosis may be mediated mainly via up-regulating the expression of apoptosis-regulated gene bax, which may be involved in its anti-tumor mechanism of bufalin.
基金National Natural Science Foundation of China(NSFC,Grant No.81673500)
文摘In the current study, we established and validated a simple and sensitive liquid chromatography-tandem mass spectrometric method for the determination of 21-hydroxy deflazacort in nude mice plasma, and such a method was applied to a pharmacokinetic study. Using betamethasone as the internal standard, the plasma samples were pre-treated by precipitation with acetonitrile and then analyzed on a reversed-phase C18 column （50 mm×2 mm, 5 μm） with a mobile phase consisting of acetonitrile and 4.0 mM ammonium formate （pH was adjusted to 3.5 with formic acid （40：60, v/v））. The analyte was detected by a triple quadrupole tandem mass spectrometer using electrospray, and multiple reaction monitoring was employed to select 21-hydroxy deflazacort at m/z 400.2/124.0 and betamethasone at m/z 393.3/147.0 in the positive ion mode. The calibration curves were linear （r〉0.99） over the range of 0.5~,00 ng/mL. The intra- and inter-day precisions and accuracies were 4.5%-10.1% and -1.7%-10.7% respectively. This method was successfully applied to a preclinical administered with a single oral dose of 4 mg/kg deflazacort, and its pharmacokinetic study of deflazacort on female nude mice pharmacokinetics was characterized by a two-compartment model with first-order absorption.
文摘AIM To establish a method of labeling anti hepatoma McAb (HAb18) Fab fragment modifier with 99m Tc. METHODS HAb18 Fab was modified with 2 iminotholane and labeled with 99m Tc by transchelation from 99m Tc GH. Labeling yield, radiochemical purity and immunoreactivity were determined by thin layer chromatography (TLC SG), paper chromatography (PC), gel chromatography (GC) and cell binding assay, respectively. The nude mice bearing human hepatoma were used for radioimmunoimaging (RII). RESULTS A radiolabeling yield of 50%-80% was obtained, and immunoreactivity (IR) was 30%-40%. Radioimaging results showed that 99m Tc HAb18 McAb Fab fragment was concentrated in the tumor 4-8 hours after injection, and the maximum concentration was seen in 12-24 hours, and the T/NT value was 5 18 and 7 48 at 6h and 8h after the injection. CONCLUSION 99m Tc HAb18 McAb Fab fragment could be specifically localized in the tumor of nude mice bearing human hepatocellular carcinoma within 24 hours and this method might be effectively used for labeling McAb Fab fragment with
文摘AIM： To establish nude mouse human gastric cancer orthotopic transplantation models using OB glue paste technique. METHODS： Using OB glue paste technique, orthtopic transplantation models were established by implanting SGC-7901 and NKN-45 human gastric cancer cell strains into the gastric wall of nude mice. Biological features, growth of the implanted tumors, the success rate of transplantation and the rate of auto-metastasis of the two models were observed. RESULTS： The success rates of orthotopic transplanration of the two models were 94.20% and 96%. The rates of hepatic metastasis, pulmonary metastasis, peritoneal metastasis, lymphocytic metastasis and splenic metastasis were 42.13% and 94.20%, 48.43% and 57.97%, 30.83% and 36.96%, 67.30% and 84.06%, and 59.75% and 10.53%, respectively. The occurrence of ascites was 47.80% and 36.96%. CONCLUSION： OB glue paste technique is easy to follow. The biological behaviors of the nude mouse human gastric cancer orthotopic transplantation models established with this technique are similar to the natural processes of growth and metastasis of human gastric cancer, and, therefore, can be used as an ideal model for experimental research of proliferative metastasis of tumors.
基金Supported by the Clinical Research Foundation of Tianjin Medical University, No. 2002KY18
文摘AIM:To investigate the change in expression of p53 ,Bcl-2 ,and Bax genes in human colon cancer cells transplanted into nude mice after hyperthermia,chemotherapy,radiotherapy,thermochemotherapy,thermoradiotherapy and thermochemoradiotherapy. METHODS:Human colon cancer cell line (HT29) was transplanted into the hind limbs of nude mice. Under laboratory simulated conditions of hyperthermia (43℃,60 min),the actual radiation doses and doses of mitomycin C (MMC) were calculated in reference to the clinical radiotherapy for human rectal cancer and chemotherapy prescription for colon cancer. The mice were divided into 6 groups according to the treatment approaches:hyperthermia,chemotherapy,radiotherapy,thermochemotherapy,thermoradiotherapy,and thermochemoradiotherapy. The mice were sacrificed at different time points and the tumor tissue was taken for further procedures. The morphologic changes in membrane,cytoplasm and nuclei of tumor cells of p53,Bcl-2,and Bax after treatment,were observed by immunohistochemistry staining. RESULTS:All of the six treatment modalities down-regulated the expression of p53,Bcl-2 and up-regulated the expression of Bax at different levels. The combined therapy of hyperthermia,with chemotherapy,and/or irradiation showed a greater effect on down-regulating the expression of p53 (0.208 ± 0.009 vs 0.155 ± 0.0115,P < 0.01) and Bcl-2 (0.086 ± 0.010 vs 0.026 ± 0.0170,P < 0.01) and up-regulating Bax expression (0.091 ± 0.0013 vs 0.207 ± 0.027,P < 0.01) compared with any single therapy.CONCLUSION:Hyperthermia enhances the effect of radio-and chemotherapy on tumors by changing the expression of apoptosis genes,such as p53,Bcl-2 and Bax.
文摘BACKGROUND: Targeting is a new therapeutic tool for malignant tumor as a result of combining nanotechnology with chemotherapeutics. The aim of our study was to investigate the effects of magnetic nanoparticles enveloping a chemotherapeutic drug on human cholangiocarcinoma xenografts in nude mice. METHODS: The human cholangiocarcinoma xenograft model was established in nude mice with the QBC939 cell line. The nude mice were randomly assigned to 7 groups. 0.9% saline or magnetic nanoparticles, including high (group 2), medium (group 4) and low (group 5) dosages, were given to nude mice through the tail vein 20 days after the QBC939 cell line was implanted. Calculations were made 35 days after treatment in order to compare the volumes, inhibition ratios and growth curves of the tumors in each group. Mice in each group were sacrificed randomly to collect tumor tissues and other organs for electron microscopy and pathological examination. RESULTS: The high and medium dosage groups were significantly different from the control group (P<0.05). The tumor inhibition ratios for the high, medium and low dosage groups were 39.6%, 14.6% and 7.9%, respectively. The tumor growth curve of groups 5, 4, and 2 changed slowly in turn. The high and medium groups showed cell apoptosis under an electron microscope. CONCLUSION: Magnetic nanoparticles can inhibit the growth of human cholangiocarcinoma xenografts in nude mice.
基金Province Science Fund for Young Scholars (No. QC05C46)Science Foundation from Health Bureau of Heilongjiang Province (No. 2005-47)
文摘Purpose： The objective of this study was to investigate the anti-tumor effects and analyze the mechanism of artesunate （ART） action on breast cancer in vivo using tumor transplanted nude mice. Methods： The human breast tumor cell line MCF-7 was transplanted into nude mice, and the animals were treated with various doses of ART alone or in combination with cyclophosphamide （CTX） or normal saline （NS）. The tumor inhibitory effects were observed and compared, and the ultrastructural morphology of the transplanted tumor cells was observed by electron microscopy. The apoptosis rates and cell cycle status were detected by flow cytometry （FCM）. The expression of apoptosis-related proteins p53, Bcl-2, Bax and Caspase-3 were detected by immunohistochemistry and IGF-IR was detected by western blot. The expression correlation for these proteins was also analyzed. Results： The tumor inhibition rates in the low dose ART group, high dose ART group, CTX group and combined drug therapy group were （24.39±10.20）%, （40.24±7.02）%, （57.01±5.84）% and （68.29±5.1）%, respectively. The cell cycle was arrested in phase G0/Gt after treatment with ART. The expression of Bcl-2 was significantly reduced, and the expression levels of Bax and Caspase-3 were significantly increased in the ART group compared to the negative control saline group. There was no significant difference detected in p53 expression. The Bcl-2 level was negatively related to Bax and Caspase-3. The western blotting results showed IGF-IR downregulation. Conclusions： ART inhibits the growth of MCF-7 breast tumor cell xenografts in nude mice. The anti-tumor mechanism of ART for human breast carcinoma in nude mice might be correlated with the alteration of apoptosis related protein expression, which may further induce apoptosis and inhibit cell proliferation.
基金Supported by The Science and Technology Fund of Jilin Province,No. 200505219
文摘AIM： To explore the effect of silencing of signal transducer and activator of transcription 3 （STAT3） expression by RNA interference （RNAi） on growth of human hepatocellular carcinoma （HCC） in tumorbearing nude mice in vivo.METHODS： To construct the recombinant plasmid of pSilencer 3.0-H1-STAT3-siRNA-GFP （pSHI-siRNA- STAT3） and establish the tumor-bearing nude mouse model of the HCC cell line SMMC7721, we used intratumoral injection together with electroblotting to transfect the recombinant plasmid pSHI-siRNA- STAT3 into the transplanted tumor. The weight of the nude mice and tumor volumes were recorded. STAT3 gene transcription was detected by semi-quantitative reverse transcription polymerase chain reaction （RT- PCR）. Level of protein expression and location of STAT3 were determined by Western blotting and immunohistochemical staining. STAT3-related genes such as survivin, c-myc, VEGF, p53 and caspase3 mRNA and protein expression were detected in tumor tissues at the same time. The terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling （TUNEL） assay was used to detect apoptosis of tumor cells.RESULTS： The weight of the treated nude mice increased, and the tumor volume decreased markedly compared with those of the mock-treated and negative control groups （P 〈 0.01）. The results of RT-PCR and Western blotting showed that mRNA and protein levels of STAT3 declined markedly in the treated group. The change in STAT3-related gene expression in tumor tissues at the mRNA and protein level also varied, the expression of survivin, VEGF and c-myc were obviously reduced, and expression of p53 and caspase3 increased （P 〈 0.01）. Most of the tumor tissue ceils in the treated group developed apoptosis that was detected by TUNEL assay.CONCLUSION： Silencing of STAT3 expression by RNAi significantly inhibits expression of STAT3 mRNA and protein, and suppresses growth of human HCC in tumor-bearing nude mice. The mechanism may be related to down-regulation of survivin, VEGF and c-myc and up-regulation of p53 and caspase3 expression. Accordingly, the STAT3 gene may act as an important and effective target in gene therapy of HCC.
基金National Natural Science Foundation of China, No. 30171060
文摘AIM： To establish a multidrug resistant （MDR） cell subline from the human hepatocardnoma cell line （HepG2） in nude mice. METHODS： HepG2 cell cultures were incubated with increasing concentrations of adriamycin （ADM） to develop an ADM-resistant cell subline （HepG2/ADM） with crossresistance to other chemotherapeutic agents. Twenty male athymic BALB/c-nu/nu mice were randomized into HepG2/nude and HepG2/ADM/nude groups （10 in each group）. A cell suspension （either HepG2 or HepG2/ADM） was injected subcutaneously into mice in each group. Tumor growth was recorded, and animals were sacrificed 4-5 wk after cell implantation. Tumors were prepared for histology, and viable tumor was dispersed into a single-cell suspension. The IC50 values for a number of chemotherapeutic agents were determined by 2, 3-bis （2-methoxy-4-nitro-5-sulfophenyl）-2H-tetrazolium-5-carboxanilide inner salt （MTT） assay. Rhodamine-123 retention/efflux and the level of resistance-associated proteins were determined by flow cytometry. The mRNA expression of mdr1, mrp and Irp genes was detected using reverse transcriptase polymerase chain reaction （RT-PCR） in HepG2/nude and HepG2/ADM/nude groups. RESULTS： The appearances of HepG2/nude cells were slightly different from those of HepG2/ADM/nude cells. Similar tumor growth curves were determined in both groups. A cross-resistance to ADM, vincristine, cisplatin and 5-fluorouracil was seen in HepG2/ADM/nude group. The levels of P-glycoprotein and multidrug resistanceassociated proteins were significantly increased. The mRNA expression levels of mdrl, mrp and/rp were higher in HepG2/ADM/nude cells. CONCLUSION： ADM-resistant HepG2 subline in nude mice has a cross resistance to chemotherapeutic drugs. It may be used as an in vivo model to investigate the mechanisms of MDR, and explore the targeted approaches to overcoming MDR.
