Pluronic modified polyamidoamine (PAMAM) conjugate (PF127-PAMAM) was prepared and the inhibiting effect of MDR against MCF-7/ADR was investigated with doxorubicin (DOX) as model drug. 1H NMR and FTIR spectra showed that the conjugate was synthesized successfully. Element analysis accurately measured that 27.63% amino of per PAMAM was modified by pluronic (PAMAM : PF127, 1 : 35.37 mole ratio). PF127-PAMAM showed an increased size and a reduced zeta potential compared to PAMAM. PF127-PAMAM had lower hemolytic toxicity and cytotoxicity due to the reduced zeta potential and the protection of PF127. Each PF127-PAMAM molecular could load 19.58 DOX molecules, and the complex exhibited sustained and pH-sensitive release behavior. PF127-PAMAM/DOX exhibited weaker cytotoxicity than free DOX in MCF-7 cells; while the complex showed much stronger reverse effect of drug resistance in MCF-7/ADR cells, and resistance reversion index (RRI) was as high as 33.15.
Dendrimers ; pharmacology ; Doxorubicin ; pharmacology ; Humans ; MCF-7 Cells ; drug effects ; Poloxamer ; pharmacology

In order to investigate the effects of Na(2)SeO(3) on expression of VEGF in K562/ADR cells, K562 and K562/ADR cells were treated with Na(2)SeO(3) at dose of 5 and 10 micromol/L. The expressions of VEGF in K562 and K562/ADR cells were detected by ELISA before and at the different time point after treatment. The mutiplie of reversion of resistance was detected by MTT method. The results showed that Na(2)SeO(3) at dose of 10 micromol/L could increase the sensitivity of K562/ADR cell to adriamycin, the multiple of reversion was 3.48. The expression levels of VEGF in K562 and K562/ADR cells increased with prolongation of time cultured, and the VEGF expression levels in K562/ADR cells at the different time points were higher than that in K562 cells (P < 0.05); 5 and 10 micromol/L Na(2)SeO(3) did not suppress expression of VEGF in K562 cells at 72 hours (P > 0.05), and the VEGF level in K562 cells at 96 hours decreased without statistical significance; 5 and 10 micromol/L Na(2)SeO(3) acting for 48 hours did not show suppressive effect on expression of VEGF in K562/ADR cells (P > 0.05), 5 micromol/L Na(2)SeO(3) could decrease the expression of VEGF in K562/ADR cell after treatment for 96 hours, while 10 micromol/L Na(2)SeO(3) could significantly decrease the expression of VEGF in K562/ADR cells treated for 72 hours and 96 hours (P < 0.01). It is concluded that VEGF would be involved in the multidrug resistance of leukemia. Na(2)SeO(3) decreasing expression of VEGF in leukemic cells may be one of the mechanisms reversing multidrug resistance.
Doxorubicin ; pharmacology ; Drug Resistance, Neoplasm ; Humans ; K562 Cells ; Sodium Selenite ; pharmacology ; Vascular Endothelial Growth Factor A ; metabolism

Antibiotics, Antineoplastic ; pharmacology ; Apoptosis ; Cell Line, Tumor ; Doxorubicin ; pharmacology ; Gangliosides ; Humans ; NF-kappa B ; metabolism

Chemotherapy as a routine method for clinical treatment of cancer has disadvantages such as significant toxicity and strong resistance. In order to improve the efficacy of the drugs and reduce the by-effects, we tried to combine static magnetic field (SMF) with cisplatin or adriamycin. The growth of Hepa1-6 cells treated with the static magnetic field (SMF) combined with cisplatin or adriamycin was significantly inhibited, as detected with MTT (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide) test. Combined treatment group cells underwent significant morphological changes as observed by HE (Hematoxylin and eosin) staining under optical microscope. Cell cycle analysis indicated that SMF increased the ratio of cells arrested in G2/M phase caused by cisplatin, and when treated with SMF combined with adriamycin, cells were almost arrested in G1 and G2/M phase. SCGE test showed that SMF can enhance the ability of cisplatin or adriamycin to promote cell DNA damage. Atomic force microscope observation found that the combination of antitumor drugs and magnetic field treatment induced larger and deeper holes on the cell membrane, and surface structure damage is serious. The combination of antitumor drugs and magnetic field technology effectively inhibits the growth of tumor cells, and reduces drug doses. The results implicate this method as potential cancer therapy.
Antineoplastic Agents ; pharmacology ; Cell Cycle ; Cell Line, Tumor ; drug effects ; Cisplatin ; pharmacology ; DNA Damage ; Doxorubicin ; pharmacology ; Humans ; Magnetic Fields

To discover an efficient strategy for the conversion of the antibacterial activity of fluoroquinolones into the antitumor activity, the three series of C-3 s-triazole-based derivatives including sulfide ketones (6a-6g), thiosemicarbazones (7a-7g) and fused heterocyclic thiazolotriazoles (8a-8g) were synthesized from ciprofloxacin (1), respectively. The structures were characterized by elemental analysis and spectral data. The antitumor activity was tested against three tumor cell lines (Hep-3B, Capan-1 and HL60) using the MTT assay. The three types of compounds all exhibited stronger anti-proliferative activities than ciprofloxacin in the test. The order of their activities was in compounds 7>8>6, and the order of selectivity against cancer cell lines was Capan-1, Hep-3B and HL60. Meanwhile, the SAR revealed that some compounds with electron-drawing group substituted such as fluoro- and nitro-phenyl compounds (6f, 7f, 8f) and (6g, 7g, 8g) displayed more significant activity than the control compounds, especially the IC50 values of thiosemicarbazone compounds 7f and 7g against Capan-1 was comparable to doxorubicin. Thus, a five-membered triazole as the C-3 bioisostere modified with the functionalized side-chain of sulfide-ketone thiosemicarbazone warrants special attention and further investigation.
Anti-Bacterial Agents ; chemistry ; Antineoplastic Agents ; pharmacology ; Cell Line, Tumor ; Ciprofloxacin ; chemistry ; Doxorubicin ; pharmacology ; HL-60 Cells ; Humans ; Ketones ; pharmacology ; Sulfides ; pharmacology ; Triazoles ; pharmacology

This study was aimed to investigate the effects of low frequency and power ultrasound combined with adriamycin on apoptosis of drug-resistant leukemia cell line K562/A02 in vitro, to find out the parameters of optimal exposure, and to explore the possible mechanism reversing drug-resistance of K562/A02 cells. The K562/A02 cells in logarithmic growth phase were used in experiments. The experiments were divided into 4 groups: group control, group adriamycin (A02) alone, group ultrasound (US) alone and group A02+US. The trypan blue dye exclusion test and MTT assay were used to determine the cell viability; Wright's staining was used to detect the apoptosis; the flow cytometry was used to analyze the drug concentration, and the scanning electron microscopy was used to observe the changes of cell surface. The results showed that the significant differences in cell viability, intracellular adriamycin concentration and changes of cell membrane were found between ultrasound-treated and untreated cells in the presence of various concentration of adriamycin. The exposure to ultrasound at 20 kHZ, 0.25 W/cm2 for 60 seconds could obviously decrease LC50 of adriamycin to K562/A02 cells, while the exposure to ultrasound at 20 kHZ, 0.05 W/cm2 for 60 seconds could kill K562/A02 cells at once. After being treated by low frequency ultrasound, the small holes with diameter about 1-2 microm in the cell surface appeared. The ultrasound increased the adriamycin concentration in the cells, accelerated the formation of apoptotic bodies, and promoted apoptosis of adriamycin-resistant cells. It is concluded that the ultrasound at optimal parameters enhances inhibitory effect of adriamycin on drug-resistant cell line, thereby reverses drug-resistance of drug-resistant cell line through sound-hole effect in tumor cells resulting from ultrasound induced cavitation.
Doxorubicin ; pharmacology ; Drug Resistance, Multiple ; Drug Resistance, Neoplasm ; Humans ; K562 Cells ; Ultrasonics

OBJECTIVETo explore the role of autophagy in doxorubicin (DOX)-induced resistance of human myeloma cell line RPMI8226.

METHODSWe established doxorubicin induced resistant subline of myeloma cell line RPMI8226/DOX by drug concentration step-elevation method. Resistant index of DOX was measured by MTT assay. Autophagy of myeloma cell lines RPMI8226/s and RPMI8226/DOX was detected by transmission electron microscopy, immunofluorescence (LC3-FITC) and western blot respectively. Apoptosis of RPMI8226/DOX cells induced by DOX combined with autophagic inhibitor hydroxychloroquine or 3-MA was identified by AnnexinV-FITC/PI double fluorescence dyeing.

RESULTSResistant index of RPMI8226/DOX was approximately 10.8 fold of that of RPMI8226/S. Electron microscopic studies revealed that most of RPMI8226/DOX cells displayed viable attributes and contained numerous autophagic vacuoles. Fluorescent images of RPMI8226/DOX cells showed a punctuate distribution in LC3 protein. Increased LC3-II protein in RPMI8226/DOX cells was determined by immunoblotting. There were no differences among 8 μmol/L HCQ (3.24±1.08)%, 10 mmol/L 3-MA (2.81±0.80)% or control \[(2.12±1.24)%\] (P>0.05) in terms of AnnexinV-FITC/PI double fluorescence dyeing; Compared with apoptosis of (9.75±2.15)%, (24.36±2.16)% and (40.51±3.14)% of RPMI8226/DOX cells under 2, 4 and 6 μmol/L DOX, apoptosis increased significantly after 24 h incubation under 2, 4 and 6 μmol/L DOX combined with 8 μmol/L HCQ as of \[(16.56±1.89)%, (36.44±2.91)% and (62.68±3.75)%, respectively\], or under 2, 4 and 6 μmol/L DOX combined with 10 mmol/L 3-MA as of \[(15.47±1.85)%, (39.28±3.06)% and (55.46±4.07)%, respectively\] (P<0.05).

CONCLUSIONAutophagy was involved in doxorubicin-induced resistance of myeloma cell line RPMI8226, DOX resistance in myeloma cells was reversed partly by autophagy inhibitor hydroxychloroquine or 3-MA, and autophagy may be one of mechanisms for drug resistance.

Autophagy ; drug effects ; Cell Line, Tumor ; Doxorubicin ; pharmacology ; Drug Resistance, Neoplasm ; Humans ; Multiple Myeloma

OBJECTIVETo analyze the difference in microRNAs expression between MCF-7 and MCF-7/ADR cells and explore the association between microRNA and drug resistance of breast cancer.

METHODSThe drug resistance of MCF-7/ADR cells was evaluated using MTT assay and flow cytometry. Microarray technique and RT-PCR were used to analyze the differential expressions of the microRNA between MCF-7 and MCF-7/ADR cells.

RESULTSThe drug resistance index of MCF-7/ADR cells relative to the parental MCF-7 cells was 33.2. The percentages of the side population in MCF-7/ADR and MCF-7 cells were (9.50-/+0.9)% and (0.85-/+0.2)%, respectively. Microarray analysis of MCF-7 to MCF-7/ADR cells identified 36 differentially expressed genes, including 16 up-regulated and 20 down-regulated genes in MCF-7/ADR cells. RT-PCR identified 14 microRNAs that were differentially expressed between MCF-7 and MCF-7/ADR cells, including 7 up-regulated and 7 down-regulated ones in MCF-7/ADR cells. Of these differentially expressed microRNAs, mir-221, mir222, mir-130a, and mir-155 showed significantly increased expression, and mir200a, mir-200b, mir-200c, and mir-421 showed significantly lowered expression in MCF-7/ADR cells as indicated by the results of microarray analysis and RT-PCR.

CONCLUSIONMCF-7/ADR cells show a different microRNA expression profile from its parental MCF-7 cells, suggesting the involvement of microRNAs in tumor cell drug resistance. This finding provides a experimental basis for further study of mechanism underlying the drug resistance of breast cancer.

Breast Neoplasms ; genetics ; Doxorubicin ; pharmacology ; Drug Resistance, Neoplasm ; genetics ; Female ; Humans ; MicroRNAs ; genetics ; Tumor Cells, Cultured

OBJECTIVESTo investigate the effect of hepatitis B virus X protein (HBx) on adriamycin-induced apoptosis of hepatocellular carcinoma cells.

METHODSHBx gene fragment was amplified from subtype adr HBV plasmid by PCR, and inserted into Hind III and Kpn I sites of green fluorescent protein (GFP) eukaryotic expression vector pEGFP-C1 to construct recombinant pGFP/HBx. The pEGFP-C1 and pGFP-HBx were introduced into HepG2 cells by Lipofectamine 2000 to obtain HepG2 cells expressing GFP. GFP-HBx fusion protein was selected using G418. The expression of HBx gene was demonstrated by RT-PCR analysis. HepG2, HepG2/GFP and HepG2/GFP-HBx cells were treated with adriamycin (2.5 microg/ml), and apoptosis of the cells was determined by their morphological changes, trypan blue exclusion, and flow cytometry analysis.

RESULTSUnder a fluorescence microscope, visible expression of GFP and GFP-HBx fusion proteins were observed in HepG2/GFP and HepG2/GFP-HBx cells, even after growing over 70 generations. RT-PCR analysis showed that HBx gene was expressed in HepG2/GFP-HBx cells. Trypan blue exclusion showed adriamycin induced time-dependent cell death in HepG2 and HepG2/GFP cells while no significant cell death was observed in HepG2/GFP-HBx cells. Flow cytometry analysis showed that apoptosis rates in HepG2/GFP-HBx (3.94%) cells were significantly lower than those in HepG2 (59.03%) and HepG2/GFP cells (61.38%) at 36 hours after the adriamycin treatment (P < 0.01). No significant differences of apoptosis rates of HepG2/GFP-HBx (3.94%) and of the untreated cells (2.12%, 2.78%, 2.55%) (P > 0.05) were observed.

CONCLUSIONA HepG2 cell line expressing GFP and GFP-HBx fusion proteins was successfully established. HBV X protein blocks adriamycin-induced apoptosis of these HepG2 cells.

Apoptosis ; drug effects ; Doxorubicin ; pharmacology ; Hep G2 Cells ; Humans ; Plasmids ; Trans-Activators ; genetics

The objective of this study was to investigate the protection by naringenin against doxorubicin-induced oxidative damage in normal blood cells. Inhibiting effects of naringenin, doxorubicin and naringenin combined with doxorubicind on K562 cells and polymorphonuclear leukocytes were detected with MTT method, the level of reactive oxygen species (ROS) and lipid peroxidation (MDA), the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were examined with spectrophotometric method in the K562 cells and polymorphonuclear leukocytes. The results indicated that the proliferation of K562 cells was not inhibited by the cytotoxicity of doxorubicin in combination of naringenin with doxorubicin. As compared with the doxorubicin, the addition of naringenin after doxorubicin for 1 hour, the levels of reactive oxygen species (ROS) and lipid peroxidation (MDA) obviously decreased, the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) obviously increased in the polymorphonuclear leukocytes, but these were not changed obviously in K562 cells. It is concluded naringenin can protect against doxorubicin-induced oxidative damage in normal blood cells. The mechanism of naringenin may be elevating activities of antioxidant enzyme and degrading oxidative production level in normal blood cells, and meanswhile decreasing level of oxidative products.
Antioxidants ; pharmacology ; Doxorubicin ; adverse effects ; Erythrocytes ; drug effects ; Flavanones ; pharmacology ; Humans ; Oxidative Stress ; Reactive Oxygen Species ; metabolism ; Superoxide Dismutase ; metabolism