The study was aimed to investigate the effect of quercetin, flavonoid molecules on reversing leukemia multidrug resistance and its mechanism. K562/A cells were cultured in vitro with different concentrations of quercetin. Cell growth inhibition and adriamycin (ADR) sensitivity were detected by MTT method. Intracellular ADR concentration was determined by flow cytometry. Cell apoptosis was assayed by Annexin V/PI staining method. The expressions of drug transporter and apoptosis related genes were measured by real-time PCR array. The results indicated that quercetin inhibited the proliferation of K562 and K562/A in 5-160 µmol/L and with dose-dependent manner. Quercetin increased the sensitivity of K562/A cells to ADR in a low toxicity concentration. Flow cytometry showed that the quercetin increased the accumulation of ADR in K562/A cells when cells were co-cultured with 5 µmol/L ADR for 2 hours. Quercetin could induce the apoptosis of K562 and K562/A cells with dose dependent manner. Furthermore, some drug transport related genes such as ATP-binding cassette (ABC) and solute carrier (SLC) and some apoptosis-related genes such as BCL-2, tumor necrosis factor (TNF), tumor necrosis factor receptor (TNFR) families were down-regulated by quercetin. It is concluded that quercetin reverses MDR of leukemic cells by multiple mechanisms and the reversing effect is positively related to drug concentration.
Drug Resistance, Multiple ; drug effects ; Drug Resistance, Neoplasm ; drug effects ; Humans ; K562 Cells ; Quercetin ; pharmacology

Multidrug resistance (MDR) of cancer cells to anti-tumor drugs remains a major impediment to successful chemotherapy. There has been an increasing interest in the studies of the mechanism and reverse of the MDR. Being a reliable and safe way to reverse MDR, drug delivery systems (DDS) such as micelle, liposome and nanoparticle, represent a promising prospect both in research and application in recent years. On the basis of recent studies, the effect and mechanism of micelles on reversing MDR are reviewed. And it is anticipated that DDS could contribute greatly to reversing MDR in the future.
Antineoplastic Agents ; administration & dosage ; pharmacology ; Drug Delivery Systems ; Drug Resistance, Multiple ; drug effects ; Drug Resistance, Neoplasm ; drug effects ; Micelles ; Nanoparticles

Drug Resistance, Multiple ; radiation effects ; Drug Resistance, Neoplasm ; radiation effects ; Hep G2 Cells ; Humans ; X-Rays

OBJECTIVETo investigate the reversing effects of curcumin on hepatocellular carcinoma drug resistance Bel7402/5-Fu cell line.

METHODSThrough the exposure to gradual increased concentrations of 5-fluorouracil (5-Fu), the cell line Bel7402 was induced to establish a multi-drug resistant sub-cell line Bel7402/5-Fu. The sensitivity to 6 chemotherapeutics of Bel7402 and Bel7402/5-Fu were detected using methyl thiazolyl tetrazolium (MTT) assay. The 50% inhibitory concentration (IC50) and resistant index (RI) were calculated. The differences of the inhibition ratio of Bel7402/5-Fu by curcumin, 5-Fu, curcumin combined with 5-Fu were detected using MTT assay. The effects of curcumin, 5-Fu, curcumin combined with 5-Fu on the Bel7402/5-Fu apoptosis were detected using flow cytometry.

RESULTSThe Bel7402/5-Fu cell line showed multi-drug resistance (MDR) to various chemotherapeutics, with the highest RI shown of 5-Fu (being 109.55 +/- 14.30 times). The inhibition ratio of 5, 10, and 20 microg/mL curcumin combined with 5-Fu (50% IC50) was respectively 21.47% +/- 1.49%, 27.10% +/- 2.32%, and 59.37% +/- 2.45%. The Bel7402/5-Fu apoptosis ratio of 5, 10, and 20 microg/mL curcumin combined with 5-Fu (50% IC50) was 30.92% +/- 2.10%, 44.87% +/- 2.24%, and 50.36% +/- 2.58%, respectively, which was obviously higher than that of the curcumin group and the 5-Fu group. Besides, the apoptosis rate increased along with increased curcumin concentration in the range of 0 -20 microg/mL.

CONCLUSIONCurcumin could induce the apoptosis of Bel7402/5-Fu. Meanwhile, it showed favorable reversing effects on MDR.

Cell Line, Tumor ; Curcumin ; pharmacology ; Drug Resistance, Multiple ; drug effects ; Drug Resistance, Neoplasm ; drug effects ; Fluorouracil ; pharmacology ; Humans

This study was aimed to evaluate the reversed effects of cyclosporin A (CsA) on multidrug resistance (MDR) of human leukemic cell line HL-60/ADM, and to investigate the relationship of the oxygen free radical content between HL-60/ADM cells and the reversed HL-60/ADM cells (HL-60/ADM + CsA). The cytotoxicity and the reversed effects of CsA on multidrug resistance of human leukemic cell line HL-60/ADM were studied by MTT, flow cytometry (FCM) and immunohistochemical assay; the oxygen free radical for HL-60/ADM and HL-60/ADM + CsA cell lines were detected by colorimetric method. The results showed that the CsA less than 4 microg/ml had no significant cytotoxicity on HL-60/ADM, while the cytotoxicity was rised with CsA concentration increasing; And CsA (4 microg/ml) combined with ADM (1 microg/ml) could obviously restrain the growth of HL-60/ADM cells (p < 0.001). The P-gp expression of HL-60/ADM decreased obviously after exposure to CsA (4 microg/ml) for 72 hours, at the same cell conditions, MDA concentration of the reversed groups (HL-60/ADM + CsA cells) was higher than that of the control groups (HL-60/ADM cells) (p < 0.05), while the levels of SOD and GSH in the reversed groups were significantly lower than that in control groups (p < 0.001). It is concluded that MDR of HL-60/ADM can be reversed effectively by low dose of CsA, the level of oxygen free radical increases and the activity of antioxidants decreases in the reversed cells. Oxygen free radicals may be involved in this reverse process, which thereby lead to the cell death.
Cyclosporine ; pharmacology ; Drug Resistance, Multiple ; drug effects ; Drug Resistance, Neoplasm ; drug effects ; HL-60 Cells ; Humans ; Reactive Oxygen Species ; metabolism

This study was to investigate the effect of phenylhexyl isothiocyanate (PHI) on drug resistance and sensitivity on K562/A02 cell line to adriamycin (ADM) and to elucidate the possible mechanisms. The inhibition rates of ADM and PHI + ADM on growth of K562/A02 cell line were measured by MTT assay, and K562/A02 cell resistant multiple was calculated. The apoptosis rate of K562/A02 cell line, the changes of intracellular ADM concentrations and MRP1 protein level were detected by flow cytometry (FCM). Intracellular reoxidized GSH level was determined by spectrometric enzyme assay and MRP1 mRNA was assayed by semiquantitative RT-PCR before and after using PHI. The results indicated that the survival rate of K562/A02 cell line decreased with the increasing concentration of PHI. Apoptosis rate increased after treatment in combination with two above drugs, the changes of drug resistance multiple and intracellular ADM level had statistical significance between K562/A02 and K562 cells (p < 0.05), when the concentration of PHI was more than 20 micromol/L. Intracellular GSH level in K562/A02 cell line reduced 5% when 1 microg/ml ADM was used alone, and it increased slightly at first, then decreased when more than 10 micromol/L PHI was used. When more than 20 micromol/L PHI was used in combination with 1 microg/ml ADM, intracellular GSH level in K562/A02 cell line decreased progressively with increasing the concentration of PHI. The expressions of MRP1 mRNA and protein had no statistical significance between K562/A02 and K562 cells (p > 0.05) after or before PHI was used. It is concluded that the cyto-toxicity of PHI to K562/A02 cell line does not associate with the depletion of the intracellular GSH. PHI not only enhances the sensitivity of K562/A02 cell line to ADM, but also partially reverses effect of K562/A02 cell resistance to ADM. ADM combined with PHI can diminish side effect and dosage of ADM.
Doxorubicin ; pharmacology ; Drug Resistance, Multiple ; drug effects ; Drug Resistance, Neoplasm ; drug effects ; Humans ; Isothiocyanates ; pharmacology ; K562 Cells

Multidrug resistance (MDR) is a major cause of cancer chemotherapy failure, and it is important to develop suitable reversal agents to overcome MDR. A majority of chemical reversal agents have acceptable reversal effects. However, the toxicity and adverse reactions associated with these agents restricts their clinical use. Chinese medicines (CMs) have lower toxicities and adverse reactions and are associated with multiple components, multiple targets and reduced toxicity. CMs have several advantages and could reverse MDR, decrease drug dosage, enhance patient compliance and increase efficacy. This review summarizes the current progress of CM reversal agents..
Drug Resistance, Multiple ; drug effects ; Drug Resistance, Neoplasm ; drug effects ; Drugs, Chinese Herbal ; pharmacology ; Humans ; Plant Extracts ; pharmacology ; Research

OBJECTIVETo investigate the mechanism of Yanshu Injection (YI) for overcoming multidrug resistance in breast carcinoma MCF-7 cells.

METHODSHuman breast carcinoma MCF-7 cells and doxorubicin-resistant MCF-7/DOX cells were treated with YI. Its inhibition on the cell proliferation was detected by MTT assay. The fluorescence intensity of doxorubicin was detected by flow cytometry. The expression of apoptosis related protein and P-glycoprotein were examined by immunoblotting after treated by YI.

RESULTSThe inhibitory action of YI on MCF-7/DOX cells was similar to that of MCF-7 cells, indicating no cross resistance (P > 0.05). 1/16 YI could obviously induce the apoptosis of MCF-7 cells and DOX cells. 1/256 YI +5 nmol/L doxorubicin and 1/128 YI +5 nmol/L doxorubicin could reduce the survival rate of MCF-7/ DOX resistant cells from 86.8% to 74.6% (P < 0.05) and 71.6% (P < 0.01) respectively, showing obvious synergistic effect. Besides, the accumulation of doxorubicin was increased after treated by YI in the MCF-7/ DOX cells. Results of immunoblotting indicated that reduction of P-glycoprotein expression was detected in MCF-7/DOX cells after exposure to YI.

CONCLUSIONYI could overcome the multidrug resistance in breast carcinoma MCF-7 cells possibly through reducing the expression of P-glycoprotein.

Apoptosis ; drug effects ; Cell Proliferation ; drug effects ; Drug Resistance, Multiple ; drug effects ; Drug Resistance, Neoplasm ; drug effects ; Drugs, Chinese Herbal ; pharmacology ; Female ; Humans ; MCF-7 Cells

Both tetrandrine (Tet) and 5-bromotetrandrine (BrTet) can effectively reverse P-glycoprotein (P-gp)-mediated multidrug resistance (MDR). The structure of multidrug resistance associated protein 7 (MRP7) has its own specificity and difference compared with other members of the MRP family. This study was aimed to investigate whether Tet and BrTet can inhibit the expression level of MRP7 so as to further look into the mechanisms of the reversal effects of Tet and BrTet on MDR. The inhibitory effects of daunorubicin (DNR) used alone on the proliferation of K562 and K562/A02 cells were evaluated by MTT assay, the IC(50) of DNR and drug resistant folds were calculated. The mRNA level of MRP7 was tested by real-time PCR, and the protein levels of MRP7 and P-gp were tested by Western blot. The DNR accumulation was analyzed by flow cytometry (FCM). The results showed that the resistance of K562/A02 cells to DNR was 23.65-folds of that of K562 cells. After administration of 1 µmol/L Tet or 2 µmol/L BrTet, the mRNA level of MRP7 in the K562/A02 cells decreased to 2% and 12% respectively, and the protein level of MRP7 decreased by 53.2% and 83.7% respectively. The protein level of P-gp decreased by 58.47% and 52.20% in the 1 µmol/L Tet and 2 µmol/L BrTet groups. FCM detection showed that 1 µmol/L Tet and 2 µmol/L BrTet significantly increased the accumulation of DNR in K562/A02 cells by 94.32% and 271% respectively. It is concluded that Tet and BrTet both can reverse MDR in vitro. The mechanisms may be related to the inhibition of MRP7 overexpression and the increase of anticancer drug concentration in cells. At the same molar concentration, the effects of Tet and BrTet in inhibiting the protein level of MRP7 expression do not show significant difference.
Benzylisoquinolines ; pharmacology ; Down-Regulation ; drug effects ; Drug Resistance, Multiple ; drug effects ; Drug Resistance, Neoplasm ; drug effects ; Humans ; K562 Cells ; Multidrug Resistance-Associated Proteins ; metabolism

Apoptosis ; drug effects ; Arsenicals ; pharmacology ; Cell Line, Tumor ; drug effects ; Drug Resistance, Neoplasm ; drug effects ; Humans ; Oxides ; pharmacology ; Point Mutation