AIMTo design and synthesize a series of new taxoids with a 5-O-sidechain, and to test the multi-drug resistant reversal activity of these compound on KB/V200 cells which is 180 times more resistant to vincristine.

METHODSUsing Sinenxan A as a common synthetic starting material, three different types of 5-O-sidechain molecules were synthesized through different route. For type I compounds, 14-acetoxy of Sinenxan A was selectively removed by hydrolysis, xanthation and reduction with tributyltin; A C-10-oxo group was introduced by PCC oxidation; 5-O-acetyl group was selectively removed by potassium tert-butoxide and finally the side chain was introduced by acylating with the corresponding acid. For type II compounds, 5-O-sidechain was introduced to the 5-deacetyl Sinenxan A which was obtained by selective hydrolysis with tBuOK. For type III compounds, 9-acetoxy group was introduced, then 5-OH was left free by thorough hydrolysis and reacetylation. Acylation at 5-position, the final product was obtained. Structure of the compounds have been confirmed by FABMS and 2DNMR. The activity of the compounds in vitro was tested on KB/V200 resistant cell line using MTT method.

RESULTSNine compounds showed resistant reversal activity and enhancing the cytotoxicity of vicristine against KB/V200 cells. Compounds I2, I3, I4 restored the sensitivity of KB/V200 towards vicristine to a level of IC50 at 1 x 10(-8) mol.L-1 which is better than the positive control Verapamil.

CONCLUSIONThe drug resistant reversal activity of taxane derivatives can be affected by substitution at different positions and the length of side chains of Sinenxan A. It is worthy to be further studied.

Antineoplastic Agents ; pharmacology ; Bridged-Ring Compounds ; chemical synthesis ; pharmacology ; Drug Resistance, Multiple ; Drug Resistance, Neoplasm ; Drug Synergism ; Humans ; KB Cells ; drug effects ; Taxoids ; chemical synthesis ; pharmacology ; Vincristine ; pharmacology

OBJECTIVETo investigate the reversing effect of NF-kappaB inhibitor MG-132 on chemoresistance of gastric cancer cells to vincristine.

METHODSIn vincristine-resistant human gastric cancer cells (SGC7901/VCR) and the parental sensitive clone (SGC7901), NF-kappaB-DNA binding activity was determined by electrophoreses mobility shift assay (EMSA). The inhibition level of kappaB (IkappaB-alpha) expression was measured by cellular-ELISA. Immunocytochemistry was used to detect the translocation of p65 and chemosensitivity of the cells was determined by MTT assay.

RESULTSCompared with the parental SGC7901 cells, both the baseline and VCR-induced NF-kappaB-DNA binding activities in various concentrations were all higher in the SGC7901/VCR cells. Pretreatment with MG-132, the NF-kappaB inhibitor, for 30 minutes remarkably reduced the NF-kappaB activation, IkappaB-alpha degradation and nuclear translocation of p65. As to the SGC7901/VCR cells and the parental sensitive SGC7901 cells, the IC(50) values for VCR were 40.03 mg/L and 0.26 mg/L, respectively. MG-132 (2.5 micromol/L) significantly enhanced the toxicity of VCR in SGC7901/VCR cells and decreased the resistance index from 154.0 to 16.5. However, MG-132 did not show an obvious effect on the VCR sensitivity in sensitive SGC7901 cells.

CONCLUSIONOur data indicate that inhibition of NF-kappaB activation in gastric cancer cells may reverse the drug resistance to VCR in the cancer cells and increase the efficiency of chemotherapy.

Adenocarcinoma ; pathology ; Antineoplastic Agents, Phytogenic ; pharmacology ; Cell Line, Tumor ; Drug Resistance, Neoplasm ; drug effects ; Humans ; Leupeptins ; pharmacology ; NF-kappa B ; antagonists & inhibitors ; Stomach Neoplasms ; pathology ; Vincristine ; pharmacology

The study was purposed to investigate the synergistic reversal effect of Chinese medicine compound FFJZ in combination with cyclosporine A (CsA) on the multidrug resistance (MDR) of human leukemia K562/VCR cell line, as to search effective combination of MDR modulators. MTT (methyl-thazol-tetrazolinum) assay were used to determine the cytotoic and reversal effects on K562/VCR cell line, FCM (flow cytometry) was used to assess the intracellular adriamycin (ADM) concentration and the expression of P-gp in cells. The results showed that the FFJZ in combination with CsA could reverse the drug-resistance of K562/VCR cells and increase the sensitivity K562/VCR cells to adriamycin. They had not the toxic effect on the K562/VCR cells in effective dose and no significant influence on P-gp positive rate of the K562/VCR cells. It is concluded that the FFJZ in combination with CsA may become a safe and effective multidrug resistance-reversing agent with low toxicity in leukemia chemotherapy.
Cyclosporine ; pharmacology ; Drug Resistance, Multiple ; drug effects ; Drug Resistance, Neoplasm ; drug effects ; Drug Synergism ; Drugs, Chinese Herbal ; pharmacology ; Humans ; K562 Cells ; Vincristine ; pharmacology

OBJECTIVETo analyze the relation between activation of NF-kappa B and chemotherapy induced apoptosis of leukemic cells and the effect of vincristine (VCR) on them.

METHODSElectrophoretic mobility shift assay (EMSA) was used to detect the activation of NF-kappa B and tunel DNA electrophoresis was adopted to observe the apoptosis induced by cytosine arabinoside (Ara-C) and etopside (Vp-16) in P388 leukemic cells.

RESULTSThe activation of NF-kappa B induced by Ara-C and Vp-16 was obviously correlated to apoptosis in P388 cells. VCR (0.1 micromol/L) could suppress activation of NF-kappa B by 52% and 63% and significantly increase the apoptosis by 89% and 123% as induced by Ara-C (100 micromol/L) and Vp-16 (100 micromol/L). The activity of NF-kappa B could be found in P388 cells before being exposed to chemotherapeutic agent.

CONCLUSIONChemotherapeutic agents can induce apoptosis and activation of NF-kappa B of P388 cells. The mechanism of VCR potentiating chemotherapeutics induction of leukemia cell apoptosis may be related to its suppression of the NF-kappa B activity in the P388 cells.

Animals ; Antineoplastic Agents, Phytogenic ; pharmacology ; Apoptosis ; drug effects ; In Situ Nick-End Labeling ; Leukemia P388 ; drug therapy ; pathology ; Mice ; NF-kappa B ; antagonists & inhibitors ; metabolism ; Vincristine ; pharmacology

More than 95% of the thyroid carcinomas are well differentiated types showing favorable prognosis. However, only a few therapeutic options are available to treat the patients with undifferentiated thyroid carcinomas, especially with refractory thyroid carcinomas that are not amenable to surgery or radioiodine ablation. We investigated the anticancer effects of 20 chemotherapy and hormonal therapy drugs on 8 thyroid carcinoma cell lines. In vitro chemosensitivity was tested using the adenosine-triphosphate-based chemotherapy response assay (ATP-CRA). The tumor inhibition rate (TIR; or cell death rate) or half maximal inhibitory concentration (IC50) was analyzed to interpret the results. Of the 12 chemotherapy drugs, etoposide (178.9 index value in follicular carcinoma cell line) and vincristine (211.7 in Hurthle cell carcinoma cell line) were the most active drugs showing the highest chemosensitivity, and of the 8 additional drugs, trichostatin A (0.03 microg/mL IC50 in follicular carcinoma cell line) showed favorable outcome having the anticancer effect. In our study, the result of etoposide and vincristine show evidence as active anticancer drugs in thyroid carcinoma cell lines and trichostatin A seems be the next promising drug. These drugs may become an innovative therapy for refractory thyroid carcinomas in near future.
Adenosine Triphosphate/chemistry/pharmacology/therapeutic use ; Antineoplastic Agents/chemistry/*pharmacology/therapeutic use ; Apoptosis/drug effects ; Cell Line, Tumor ; Etoposide/chemistry/pharmacology/therapeutic use ; Humans ; Hydroxamic Acids/chemistry/pharmacology/therapeutic use ; Thyroid Neoplasms/drug therapy ; Vincristine/chemistry/pharmacology/therapeutic use

OBJECTIVETo explore the reversal effect and potential mechanism of resveratrol on multidrug resistance of human oral epidermoid carcinoma KBv200 cells.

METHODSMTT assay was used to investigate reversal index of resveratrol to vincristine, adriamycin and paclitaxel. Cell apoptosis were measured by flow cytometry. RT-PCR and Western blot were used to detect mRNA and protein expression of multidrug resistant 1 (MDR1) and B cell lymphoma leukemia-2 (Bcl-2).

RESULTSResveratrol produced a synergistic effect with chemotherapeutics and obviously reversed the multidrug resistant phenotype of KBv200 cells. The reversal fold (RF) of 200 micromol/L resveratrol to vincristine, paclitaxel and adriamycin were 77.1, 61.3 and 5.9, respectively. The gene array results showed that resveratrol greatly downregulated expression levels of Bcl-2 and MDR1. After treated with 100 micromol/L, 200 micromol/L resveratrol, the expression level of Bcl-2 and MDR1 in KBv200 cells were markedly decreased in comparison with those untreated (t were 2.98, 3.51 and 3.12, 4.56, P < 0.05).

CONCLUSIONSResveratrol can efficiently reverse multidrug resistance in KBv200 cells. The potential mechanism may be via inhibiting the multidrug resistant gene expressions and/or promoting cell apoptosis.

Antineoplastic Agents ; pharmacology ; Apoptosis ; drug effects ; Cell Line, Tumor ; Doxorubicin ; pharmacology ; Drug Resistance, Multiple ; drug effects ; Drug Resistance, Neoplasm ; drug effects ; Drug Synergism ; Humans ; Paclitaxel ; pharmacology ; Stilbenes ; pharmacology ; Vincristine ; pharmacology

In order to investigate the regulative function of telomerase and phosphorylated (activated) extracellular regulated protein kinase (ERK) 1 and 2 in the leukemic cell lines HL-60 and K562 proliferation inhibition and apoptosis, three chemotherapeutic drugs Harringtonine (HRT), Vincristine (VCR) and Etoposide (Vp16) were selected as inducers. The proliferation inhibition rate was detected by MTT method, the cell cycle and cell apoptosis was analyzed by flow cytometry and the telomerase activity was detected by the telomeric repeat amplification protocol (TRAP) assay and bioluminescence analysis method. The phosphorylated ERK1/2 protein expression was detected by western blot method. The results showed that HRT, VCR and Vp16 could inhibit cell proliferation, induce apoptosis, inhibit telomerase activity and down-regulate the protein expression of phosphorylated ERK. It was suggested that ERK signal transduction pathway was involved in the down-regulation of telomerase activity and the onset of apoptosis in the leukemic cells treated by HRT, VCR and Vp16.
Antineoplastic Agents ; pharmacology ; Apoptosis ; drug effects ; Cell Division ; drug effects ; Down-Regulation ; Etoposide ; pharmacology ; HL-60 Cells ; Harringtonines ; pharmacology ; Humans ; K562 Cells ; Mitogen-Activated Protein Kinase 3 ; Mitogen-Activated Protein Kinases ; metabolism ; Phosphorylation ; Telomerase ; metabolism ; Vincristine ; pharmacology

AIMTo study the anti-angiogenic activity of novobiocin and its mechanism of action.

METHODSThe anti-angiogenic activity of novobiocin was determined using chick embryo chorioallantoic membrane(CAM) assay. MTT assay, zymography and related assays were used to observe the effects of drugs on bovine aorta endothelial cells and human pulmonary carcinoma PG cells.

RESULTSNovobiocin at the doses of 100 and 200 micrograms/egg inhibited angiogenesis by 31.6% and 68.7% in CAM, respectively. The combination of novobiocin and vincristine enhanced the anti-angiogenic effect. Novobiocin inhibited the proliferation of bovine aortic endothelial cells in a concentration-dependent manner. In addition, novobiocin suppressed MMP-2 secretion, migration, and tube formation of endothelial cells. As determined by MTT assay, novobiocin in combination with vincristine displayed synergistic effect on the proliferation of PG cells,

CONCLUSIONThis study demonstrates that novobiocin is active in suppressing angiogenesis and the anti-angiogenic activity may be enhanced by combination with vincristine. The anti-angiogenic activity of novobiocin may be related, at least in part, to its inhibition of cell proliferation, cell migration, tube formation and secretion of matrix metalloproteinases.

Angiogenesis Inhibitors ; pharmacology ; Animals ; Antineoplastic Agents, Phytogenic ; pharmacology ; Cattle ; Cell Division ; drug effects ; Cell Movement ; drug effects ; Chick Embryo ; Drug Synergism ; Endothelial Cells ; cytology ; Humans ; Matrix Metalloproteinase 2 ; metabolism ; Neovascularization, Physiologic ; drug effects ; Novobiocin ; pharmacology ; Tumor Cells, Cultured ; Vincristine ; pharmacology

OBJECTIVELeukemia is the most common malignancy in children. Combined chemotherapy is currently the primary treatment modality. During the past decade, very high cure rates of childhood acute lymphoblastic leukemia (ALL) have been reported both at home and abroad. However, the cure rates of children with acute myeloid leukemia (AML) remain low due to the multiple-drug resistance (MDR). P-glycoprotein (P-gp) is one of the most important mechanisms of MDR for leukemia cells. However, the function of the protein, the clinical application of its reversal agents and the efficacy of the combination of the reversal agents remain to be elucidated. The present study aimed to evaluate the P-gp pump function on leukemia cell membrane and the effects of the combined administration of the reversal agents cyclosporin A (CSA) and verapamil (VER) through the observation of Calcein-AM (C-AM) metabolism in the cell line K562 and its multi-drug resistant subline K562/VCR.

METHODSThe mean fluorescence intensity (MFI) of C-AM inside the cytoplasm was analyzed with flow cytometry (FCM). The events of K562 and K562/VCR cells treated and untreated with CSA, VER and CSA + VER were acquired at time points 0, 30, 60, 90 and 120 minutes, respectively, and the data obtained were analyzed with CellQuest software.

RESULTSThe C-AM in the K562 and K562/VCR varied more apparently in the fist 24 hours. In addition, the MFI of the C-AM in K562 was significantly higher than that in K562/VCR cells indicating that the P-gp pump molecules were functioning. The MFIs of the CSA, VER and CSA + VER groups co-cultured with K562/VCR cells were 4014 +/- 219, 3879 +/- 116 and 4158 +/- 302, respectively after 120 min of incubation, significantly higher as compared to that of control group (3251 +/- 107, P < 0.05). On the other hand, significant inhibition of the efflux from the K562/VCR cell line was also noticed after the same time period of incubation with the MFIs of 2237 +/- 155, 1932 +/- 233 and 2231 +/- 147, respectively in the three groups, which was significantly higher than that of control group (1622 +/- 191, P < 0.05). CSA, VER and CSA + VER could increase the uptake and inhibit the efflux of C-AM by K562/VCR cells, while no evident influence on those functions inside the parental cell line K562 cells was noticed.

CONCLUSIONSCSA, VER and CSA + VER could increase the uptake and reduce the efflux of C-AM by K562/VCR cells while no significant difference between the CSA + VER and CSA or VER was noticed. P-gp pump function and the effects of its reversal agents on leukemic cells can be rapidly and easily evaluated by using the C-AM and FCM.

ATP-Binding Cassette, Sub-Family B, Member 1 ; metabolism ; Antineoplastic Agents ; pharmacology ; Child ; Drug Resistance, Multiple ; drug effects ; Flow Cytometry ; methods ; Fluoresceins ; pharmacology ; Humans ; K562 Cells ; Tumor Cells, Cultured ; Verapamil ; pharmacology ; Vincristine ; pharmacology

OBJECTIVETo investigate if CYP3A5 gene is involved in the molecular mechanisms for multiple drug resistance in leukemia cells.

METHODSA full length cDNA of CYP3A5 gene was cloned, and a recombinant eukaryotic expression plasmid was constructed, then stably transfected cell lines were established. Furthermore, the sensitivity of those cell lines to several anticancer drugs were assessed by MTT and FCM assay.

RESULTSThe recombinant plasmid was designated as pcDNA3-CYP3A5. Transfecting HL-60 cells (which didn't show transcript of CYP3A5 gene) with recombinant plasmid pcDNA3-CYP3A5 generated HL-60/CYP3A5 cell line, and transfecting of HL-60 cells with the parental pcDNA3 vector served as control HL-60/pc cell line. Daunorubicin induced remarkable apoptosis peaks in HL-60 and HL-60/pc cells, while such effect did not occur in HL-60/CYP3A5 cells (apoptosis cell percentage were 7.3%, 6.3% and 1.2%, respectively). Compared with HL-60 and HL-60/pc cells, HL-60/CYP3A5 cells were statistically significantly resistant to daunorubicin, aclacinomycin A, vincristine and harringtonine (resistance multiples were 2.89, 2.01, 4.05 and 2.79 times, respectively, P < 0.05), however the sensitivity to teniposide didn't change (resistance multiple was 1.04 times).

CONCLUSIONTranscription of CYP3A5 gene in leukemia cells directly induces resistance to anthracyclines and alkaloids, however the cells are still sensitive to epipodophyllotoxins. Therefore, our findings confirmed a new mechanism of multidrug resistance.

Aclarubicin ; pharmacology ; Antibiotics, Antineoplastic ; pharmacology ; Cytochrome P-450 CYP3A ; Cytochrome P-450 Enzyme System ; genetics ; Daunorubicin ; pharmacology ; Drug Resistance, Multiple ; genetics ; Drug Resistance, Neoplasm ; genetics ; HL-60 Cells ; Humans ; Phenotype ; Plasmids ; genetics ; Recombination, Genetic ; Transfection ; Vincristine ; pharmacology