droloxifene and tetrandrine

To study the effect of tetrandrine (Tet) in combination with droloxifen (DRL) on the expression of nuclear factor kappa B (NF-kappaB) in K562 and K562/A02 cell lines and its reversal mechanism.. The activation of NF-kappaB in K562 and K562/A02 cell lines and the effect of Tet or DRL alone or in combination on NF-kappaB protein expression were determined with immunocytochemistry and Western blotting respectively.. (1) K562/A02 cells displayed higher level of NF-kappaB protein expression than K562 cells. (2) The application of Tet or DRL alone or in combination had no effect on NF-kappaB expression in K562 cells at 6 h and 12 h (P > 0.05). (3) Tet and DRL alone or in combination could significantly down-regulate NF-kappaB protein expression in nuclei of K562/A02 cells. The effect was more significant in combination than either alone. This effect was more significant at 12 h than at 6 h.. (1) Activation of NF-kappaB may be involved in the mechanism of MDR of K562/A02 cell line. (2)Inhibition of NF-kappaB activation may be involved in the reversal of multidrug resistance in K562/A02 cells by Tet and DRL.

Topics: Benzylisoquinolines; Drug Resistance, Multiple; Humans; K562 Cells; NF-kappa B; Tamoxifen

To observe the effect of Tetrandrine (tet) combined with Droloxifen (DRL) on the expression of bcr/abl mRNA and P(210) BCR/ABL protein of K562 cell line, after K562 cells were cultured in the medium containing Tet (1 micromol/L), DRL (5 micromol/L) separately or in their combination for some time, the changes of bcr/abl mRNA and protein expression were detected by RT-PCR and Western blot respectively. The results showed that the application of single drug of Tet or DRL had no effect on bcr/abl mRNA and BCR/ABL protein expression in K562 cell line. However, Tet in combination with DRL began to downregulate bcr/abl mRNA and P(210) BCR/ABL expression of K562 cells at 48 h and 72 h, respectively. It is concluded that tetrandrine in combination with Droloxifen can downregulate the expression of bcr/abl mRNA and P(210) BCR/ABL protein and the combination may be involved in the mechanism underlying the reverse effects on multidrug resistance in leukemia.

Topics: Antineoplastic Agents; Benzylisoquinolines; Blotting, Western; Down-Regulation; Drug Synergism; Fusion Proteins, bcr-abl; Gene Expression Regulation, Leukemic; Humans; K562 Cells; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Tamoxifen

The aim of this study was to investigate the mechanism to reverse the drug resistance of leukemia cells in tetrandrine (Tet) alone or in combination with droloxifen (Drol) by using protein chips and to lay the theoretical basis for the clinical applications. Three monoclonal antibodies against P-glycoprotein (P-gp), the multidrug resistance-associated protein (MRP1) and the breast cancer resistance protein (BCRP) were immobilized onto the agarose gel film-coated glass slides. Protein chips were prepared respectively from K562/A02 cells cultured for 12, 24 and 48 hours with Tet alone or in combination with Drol. The results showed that Tet alone or in combination with Drol could decrease only the expression of P-gp in a time-dependent manner, the effect for 48 hours as follows: Tet + Drol 82.620 +/- 3.227; Tet alone 86.440 +/- 2.906; Drol alone 87.230 +/- 2.049; control 93.670 +/- 2.748 (P < 0.05). However, down-regulation of P-gp by K562/A02 cells cultured with Tet alone or in combination with Drol began at 24 hours (Tet + Drol 85.270 +/- 3.095; control 93.670 +/- 2.748, P < 0.05). The results were coincident with that of FCM. It is concluded that Tet and Drol can downregulate the expression of P-gp in the time-dependent way. There is a significant difference between Tet alone and Tet combined with Drol at 24 hours (P < 0.05). The expression of MRP1 and BCRP are not closely correlated with the reversal mechanism of Tet and Drol, and which may be involved in the mechanism of this combination to reverse multidrug resistance in leukemia.

Topics: Antineoplastic Agents; ATP Binding Cassette Transporter, Subfamily B, Member 1; ATP Binding Cassette Transporter, Subfamily G, Member 2; ATP-Binding Cassette Transporters; Benzylisoquinolines; Drug Resistance, Multiple; Drug Resistance, Neoplasm; Drug Synergism; Humans; K562 Cells; Leukemia; Multidrug Resistance-Associated Proteins; Neoplasm Proteins; Protein Array Analysis; Tamoxifen

To explore the relationship of multidrug resistance formation in K562/A02 cells with the intracellular concentration of [Ca(2+)]i, the cytotoxicities of daunorubicin (DNR) were assayed by MTT method, the variations of [Ca(2+)]i of K562 cells and K562/A02 cells after treatment of Tet, DRL and DNR alone or in combination were detected by using Fura-2/AM. The results showed as follows: (1) The cytotoxicities of DNR to cell line K562/A02 were enhanced by 1 micro mol/L Tet or 5 micro mol/L DRL. Their IC(50) was (7.28 +/- 2.06) micro g/ml and (7.58 +/- 3.44) micro g/ml; multiple of their reversal effect was 2.94 and 2.82, but IC(50) of combined Tet and DRL was (1.66 +/- 0.41) micro g/ml. Its reverse effect distinctly increased by 12.9 times. (2) The [Ca(2+)]i in K562/A02 cells were higher than that in K562 cells. (3) One micro mol/L Tet and 5 micro mol/L DRL alone increased the [Ca(2+)]i in K562/A02 cells time-dependently and there was antagonism when both were used. It is concluded that high [Ca(2+)]i is supposed to be a reason of MDR in K562/A02 cells, the action of resistance modifying agents (RMA) in MDR reverse course, however, needs further research.

Topics: Alkaloids; Benzylisoquinolines; Calcium; Daunorubicin; Drug Resistance, Multiple; Drug Resistance, Neoplasm; Humans; K562 Cells; Tamoxifen

To study the correlation of the reversal effect of tetrandrine (Tet) in combination with droloxifene (DRL) on multidrug resistant cell line K562/A02 and induction apoptosis, the apoptosis of K562 cells and K562/A02 cells after the treatment of Tet and DRL alone or their combination was detected by flow cytometry (FCM). The results showed 0.62 microg/ml Tet and 1.94 microg/ml DRL alone could induce apoptosis of K562 cells in time-dependent manner after culture for 48 hours. Neither Tet at 0.62 microg/ml nor DRL at 1.94 microg/ml alone could induce apoptosis of K562/A02 cells, but in the combination of them two induced apoptosis of few K562/A02 cells in culture for 72 hours. In conclusion, the mechanism of Tet and DRL reversing multidrug resistance has no correlation with the apoptosis of K562/A02 cells.

Topics: Alkaloids; Apoptosis; Benzylisoquinolines; Drug Resistance, Multiple; Drug Resistance, Neoplasm; Drug Therapy, Combination; Flow Cytometry; Humans; K562 Cells; Tamoxifen