Toxicity Of Dox Research Articles

Luteolin as a glycolysis inhibitor offers superior efficacy and lesser toxicity of doxorubicin in breast cancer cells

Luteolin (Lu) exhibits a wide spectrum of anti-tumor activities, the present study was to observe whether Lu can sensitize breast cancer cells to doxorubicin (Dox) and to explain the basis underlying this phenomenon. In vitro, Lu at dose less than 100 μM had only slight effect on cells growth and cytotoxicity of Dox in 4T1 and MCF-7 cells under normoxia, but it could reverse tumor resistance to Dox and promote death of tumor cells under hypoxia. In vivo, Lu alone had also no effect on tumor growth delay, however, it could offer superior efficacy and lesser toxicity of Dox in 4T1 and MCF-7 bearing mice. Further study showed that Lu was able to suppress glycolytic flux but did not affect glucose uptake, the P-glycoprotein, anti-oxidative enzymes under hypoxia in vitro, and had not also effect on the intratumor Dox level in vivo. In addition, the activity of SOD and CAT was increased in serum and was decreased in tumor by Lu in vivo. These results suggest that luteolin as a glycolytic inhibitor might be a new adjuvant agent for chemotherapy.

Persistent Alterations to the Gene Expression Profile of the Heart Subsequent to Chronic Doxorubicin Treatment

Doxorubicin (DOX, Adriamycin) is a potent antineoplastic agent used to treat a number of cancers. Despite its utility, DOX causes a cumulative, irreversible cardiomyopathy that may become apparent shortly after treatment or years subsequent to therapy. Numerous studies have been conducted to elucidate the basis of DOX cardiotoxicity, but the precise mechanism responsible remains elusive. This investigation was designed to assess global gene expression using microarrays in order to identify the full spectrum of potential molecular targets of DOX cardiotoxicity to further delineate the underlying pathological mechanism(s) responsible for this dose-limiting cardiomyopathy. Male, Sprague-Dawley rats received 6 weekly injections of 2 mg/kg (s.c.) DOX followed by a 5 week drug-free period prior to analysis of cardiac tissue transcripts. Ontological evaluation in terms of subcellular targets identified gene products involved in mitochondrial processes are significantly suppressed, consistent with the well-established persistent mitochondrial dysfunction. Further classification of genes into biochemical networks revealed several pathways modulated by DOX, including glycolysis and fatty acid metabolism, supporting the notion that mitochondria are key targets in DOX toxicity. In conclusion, this comprehensive transcript profile provides important insights into critical targets and molecular adaptations that characterize the persistent cardiomyopathy associated with long-term exposure to DOX.

The anti-hepatitis drug DDB chemosensitizes multidrug resistant cancer cells in vitro and in vivo by inhibiting P-gp and enhancing apoptosis

DDB (dimethyl-4,4'-dimethoxy-5,6,5'6'-dimethylene dioxybiphenyl-2,2'-dicarboxylate) is a synthetic hepatoprotectant which has been widely used to treat chronic viral hepatitis B patients in China for more than 20 years. In this study, we evaluated DDB as a multidrug resistance (MDR) chemosensitizing agent. A panel of sensitive and resistant cancer cell lines were treated with various concentration of DDB, and the effect on chemosensitivity and accumulation of anticancer drugs; promotion of apoptosis and P-glycoprotein (P-gp) expression were determined by MTT (Dimethyl thiazolyl-2,5-diphenyltetrazolium bromide) assay, fluorospectrometry and flow cytometry respectively. Drug resistance reversal activity of DDB was also examined in BALB/c nude mice bearing both acquired MDR human nasopharyngeal carcinoma KBv200 and parental KB xenografts. The effect of DDB on the pharmacokinetics of Dox and hematological toxicity induced by Dox was measured in ICR and C(57)/BL mice, respectively. DDB at nontoxic concentrations of 12.5, 25 and 50 microM partly reversed the resistance to vincristine, doxorubicin, paclitaxel in acquired MDR breast carcinoma MCF-7/Adr cells, KBv200 and intrinsic MDR human hepatocarcinoma Bel(7402) cells, whereas no chemosensitizing effect of DDB was observed in sensitive KB and MCF-7 cells. DDB increased the intracellular accumulation of doxorubicin and inhibited surface P-gp expression in MCF-7/Adr cells. Furthermore, it was found that DDB promoted doxorubicin-induced apoptosis of Bel(7402) cells through enhanced caspase-3 activation. Co-administration of DDB at 300 and 500 mg/kg orally to nude mice increased the antitumor activity of vincristine to KBv200 xenografts without a significant increase in toxicity. In contrast, Co-administration of DDB did not inhibit the growth of KB xenografts. DDB also markedly reduced the decrease of leukocytes in doxorubicin-treated C(57)/BL mice. Co-administration of DDB increased Dox concentration in ICR mice bearing S180 sarcoma, but no pharmacokinetical interaction with Dox was observed. These results indicate that DDB has MDR reversal activity by inhibiting P-gp and when used in combination with anti-cancer drugs, it could potentially be used as a clinical treatment for P-gp-mediated MDR cancers.

A New Polymer–Lipid Hybrid Nanoparticle System Increases Cytotoxicity of Doxorubicin Against Multidrug-Resistant Human Breast Cancer Cells

This work is intended to develop and evaluate a new polymer-lipid hybrid nanoparticle system that can efficiently load and release water-soluble anticancer drug doxorubicin hydrochloride (Dox) and enhance Dox toxicity against multidrug-resistant (MDR) cancer cells. Cationic Dox was complexed with a new soybean-oil-based anionic polymer and dispersed together with a lipid in water to form Dox-loaded solid lipid nanoparticles (Dox-SLNs). Drug loading and release properties were measured spectrophotometrically. The in vitro cytotoxicity of Dox-SLN and the excipients in an MDR human breast cancer cell line (MDA435/LCC6/MDR1) and its wild-type line were evaluated by trypan blue exclusion and clonogenic assays. Cellular uptake and retention of Dox were determined with a microplate fluorometer. Dox-SLNs were prepared with a drug encapsulation efficiency of 60-80% and a particle size range of 80-350 nm. About 50% of the loaded drug was released in the first few hours and an additional 10-20% in 2 weeks. Treatment of the MDR cells with Dox-SLN resulted in over 8-fold increase in cell kill when compared to Dox solution treatment at equivalent doses. The blank SLN and the excipients exhibited little cytotoxicity. The biological activity of the released Dox remained unchanged from fresh, free Dox. Cellular Dox uptake and retention by the MDR cells were both significantly enhanced (p < 0.05) when Dox was delivered in Dox-SLN form. The new polymer-lipid hybrid nanoparticle system is effective for delivery of Dox and enhances its efficacy against MDR breast cancer cells.

Impact of body composition on pharmacokinetics of doxorubicin in pediatric patients: A Glaser Pediatric Research Network study

8519 Background Body composition affects various physiologic processes involved in the distribution, metabolism, and elimination of drugs. Therefore body composition might be related to important pharmacokinetic (PK) parameters like clearance or half-life. These relationships have never been systematically studied for doxorubicin (dox) and its metabolite doxorubicinol (doxol). In addition, the PK behavior of dox and doxol have not been thoroughly described in children. In this study we evaluated the relationship between body composition and doxorubicin PK in children. Methods Eligible subjects were ≥ 1 and ≤ 21 years old; weighed ≥ 12 kg; received dox administered as an infusion of any duration < 24 hours, on either a 1-day or 2-day schedule; had ALT/AST ≤ 3 times the upper limit of normal and bilirubin ≤ upper limit of normal tested within 14 days prior to dox; and provided informed consent/assent. Blood samples were drawn prior to dox administration, at the midpoint of the infusion and at 0, 0.5, 1, 1.5, 2, 3, 4, 6, 8, 12, 24, and 48 hours after the infusion for 1-day schedules, or at 0, 0.5, 1, 2, 4, and 6, hours after the day 1 infusion and immediately prior to the day 2 infusion, then at 0, 0.5, 1, 1.5, 2, 4, 6, 8, 12, 24, and 48 hours after the day 2 infusion for 2-day schedules. Body composition was determined using dual-energy x-ray absorptiometry (DXA). Body mass index (BMI) was calculated from height and weight. Dox and doxol concentrations were analyzed by reverse-phase high-pressure liquid chromatography with fluorescence detection. Dox plasma PK were analyzed with maximum likelihood estimation as implemented in ADAPT II. Results Data are available for 16 subjects (12 male; 8 Hispanic, 6 Caucasian, 2 Asian). The median age is 15 years (range 3–21). The median % body fat by DXA is 22 % (range 16–36). The median BMI is 20 (range 14–30). The median dox clearance is 382 ml/m2/min (range 141–768). The median terminal half-life is 30.6 hr (range 18.1–146.6). Dox clearance decreases with increasing BMI (r=-0.56, P=0.02) and tends to decrease with increasing % body fat (r=-0.43, P=0.10). Conclusions Potential relationships between increasing BMI, decreasing dox clearance, and dox toxicity should be explored. No significant financial relationships to disclose.

Effect of O-4-ethoxyl-butyl-berbamine in combination with pegylated liposomal doxorubicin on advanced hepatoma in mice.

To study the synergistic effects of calmodulin (CaM) antagonist O-4-ethoxyl-butyl-berbamine (EBB) and pegylated liposomal doxorubicin (PLD) on hepatoma-22 (H(22)) in vivo. Hepatoma model was established in 50 Balb/c mice by inoculating H(22) cells (2.5 x 10(6)) subcutaneously into the right backs of the mice. These mice were divided into 5 groups, and treated with saline only, PLD only, doxorubicin (Dox) only, PLD plus EBB and Dox plus EBB, respectively. In the treatment groups, mice were given 5 intravenous of PLD or Dox on days 0, 3, 6, 9 and 12. The first dosage of PLD or Dox was 4.5 mg/kg, the other 4 injections was 1 mg/kg. EBB (5 mg/kg) was coadministered with PLD or Dox in the corresponding groups. The effect of drugs on the life spans of hepatoma-bearing mice and tumor response to the drugs were recorded. Dox levels in the hepatoma cells were measured by a fluorescence assay. Light microscopy was performed to determine the histopathological changes in the major organs of these tumor-bearing mice. The MTT method was used to analyze the effect of Dox or PLD alone, Dox in combination with EBB, or PLD in combination with EBB on the growth of H(22) cells in an in vitro experiment. EBB (5 mg/kg) significantly augmented the antitumor activity of Dox or PLD, remarkably prolonged the median survival time. The median survival time was 18.2 d for control group, but 89.2 d for PLD+EBB group and 70.1 d for Dox+EBB group, respectively. However, Dox alone did not show any remarkable antitumor activity, and the median survival time was just 29.7 d. Addition of EBB to Dox or PLD significantly increased the level of Dox in H(22) cells in vivo. Moreover, EBB diminished liver toxicity of Dox and PLD. In vitro, EBB reduced the IC50 value of Dox or PLD on H(22) cells from 0.050+/-0.006 mg/L and 0.054+/-0.004 mg/L to 0.012+/-0.002 mg/L and 0.013+/-0.002 mg/L, respectively (P<0.01). EBB and liposomization could improve the therapeutic efficacy of Dox in liver cancer, while decreasing its liver toxicity.

Development of an intrinsic P-glycoprotein-mediated doxorubicin resistance in quiescent cell layers of large, multicellular prostate tumor spheroids.

Growing multicellular prostate tumor spheroids develop quiescent cell subpopulations in central regions with features of intrinsic multicell-mediated drug resistance. Doxorubicin (dox) uptake was significantly reduced in large spheroids (diameter 400+/-70 microm), which consist predominantly of quiescent cells, as compared to small spheroids (diameter 100+/-50 microm), which consist entirely of proliferating cells. After removal of dox from the incubation medium, dox fluorescence declined more efficiently in large spheroids, which led to a decreased dox toxicity as revealed by colony-forming assays. Verapamil significantly increased dox retention in large spheroids and, consequently, augmented dox toxicity. At a depth 80 microm from the spheroid periphery, a significantly decreased dox fluorescence was observed in the deep, quiescent cell layers of large spheroids. The P-glycoprotein-mediated multidrug resistance (MDR)-reversing agents verapamil, cyclosporin A, quinidine, sodium orthovanadate and tamoxifen significantly increased dox fluorescence at this depth, whereas genistein, indomethacin, probenecid and brefeldin A, which reverse multidrug-resistance-associated protein (MRP) function, exerted no effect. Anti-P-glycoprotein immunohistochemistry of multicellular tumor spheroids revealed an increase of P-glycoprotein expression in large speroids as compared to small spheroids, which was most prominent in the Ki-67-negative, quiescent cell layers 60 to 100 microm distant from the periphery of the spheroid, indicating that the MDR phenotype is related to cell quiescence. This was corroborated by whole-cell patch-clamp experiments, where the C219 antibody, which is directed against the ATP-binding site of P-glycoprotein, significantly inhibited P-glycoprotein-associated, volume-activated chloride currents in quiescent, but not proliferating cells from multicellular tumor spheroids.

Development of an intrinsic P‐glycoprotein‐mediated doxorubicin resistance in quiescent cell layers of large, multicellular prostate tumor spheroids

Growing multicellular prostate tumor spheroids develop quiescent cell subpopulations in central regions with features of intrinsic multicell-mediated drug resistance. Doxorubicin (dox) uptake was significantly reduced in large spheroids (diameter 400 ± 70 μm), which consist predominantly of quiescent cells, as compared to small spheroids (diameter 100 ± 50 μm), which consist entirely of proliferating cells. After removal of dox from the incubation medium, dox fluorescence declined more efficiently in large spheroids, which led to a decreased dox toxicity as revealed by colony-forming assays. Verapamil significantly increased dox retention in large spheroids and, consequently, augmented dox toxicity. At a depth 80 μm from the spheroid periphery, a significantly decreased dox fluorescence was observed in the deep, quiescent cell layers of large spheroids. The P-glycoprotein-mediated multidrug resistance (MDR)-reversing agents verapamil, cyclosporin A, quinidine, sodium orthovanadate and tamoxifen significantly increased dox fluorescence at this depth, whereas genistein, indomethacin, probenecid and brefeldin A, which reverse multidrug-resistance-associated protein (MRP) function, exerted no effect. Anti-P-glycoprotein immunohistochemistry of multicellular tumor spheroids revealed an increase of P-glycoprotein expression in large speroids as compared to small spheroids, which was most prominent in the Ki-67-negative, quiescent cell layers 60 to 100 μm distant from the periphery of the spheroid, indicating that the MDR phenotype is related to cell quiescence. This was corroborated by whole-cell patchclamp experiments, where the C219 antibody, which is directed against the ATP-binding site of P-glycoprotein, significantly inhibited P-glycoprotein-associated, volume-activated chloride currents in quiescent, but not proliferating cells from multicellular tumor spheroids. Int. J. Cancer 75:855–863, 1998. © 1998 Wiley-Liss, Inc.

Doxorubicin-heparin complex: reduction of cardiotoxicity of doxorubicin.

We have compared the antitumor activity and cardiotoxicity of free doxorubicin (Dox) and doxorubicin-heparin complex in vivo and in vitro. Dox and Dox-heparin complex equally inhibited the DNA synthesis of leukemic cells and showed a similar anticancer activity against tumor-bearing mice. Acute toxicity of Dox at the dose of 20 mg/kg or 30 mg/kg was significantly more profound than that of the Dox-heparin complex, which was demonstrated by survival rate (P < 0.01). Chronic toxicities of Dox and the Dox-heparin complex were compared by giving the respective reagent (2 mg/kg) weekly for 20 weeks. The weight gains of the mice given Dox-heparin complex were greater than those of the mice given Dox alone (P < 0.01). The pathological damage to the cardiac tissue in mice treated with Dox-heparin complex was significantly less severe than that of mice treated with Dox. Thus, the present study indicates that complexing with heparin diminished the acute and chronic toxicity of Dox without reducing its antitumor activity in mice, and suggests a possible clinical application of Dox-heparin complex in humans.

Differential modulation of doxorubicin toxicity to multidrug and intrinsically drug resistant cell lines by anti-oestrogens and their major metabolites

The ability of the anti-oestrogens tamoxifen, toremifene and their 4-hydroxy and N-desmethyl metabolites to modify doxorubicin (dox) toxicity to intrinsically resistant and multidrug resistant cell lines was compared, using human breast and lung cancer, and Chinese hamster ovary cell lines. The anti-oestrogens significantly enhanced dox toxicity to multidrug resistant, P-glycoprotein-positive cell lines, but did not affect toxicity to intrinsically resistant, P-glycoprotein-negative cells. Modification was observed at clinically achievable anti-oestrogen concentrations. Toremifene and tamoxifen would therefore appear to be good candidates for in vivo studies as MDR modulating agents in selected patients with P-glycoprotein-positive tumours.

Differential in vitro sensitivity of human tumor and normal cells to chemotherapeutic agents and resistance modulators

The intrinsically Vincristine(Vcr)-resistant human kidney adenocarcinoma cell line ACHN, the human acute lymphoblastic leukemia cell line L0, its more-than-100-fold Vcr-resistant subline LI00, normal human fibroblasts and lymphocytes, also tumor cells from patients with chronic lymphocytic leukemia (CLL), acute myeloblastic leukemia (AML) and solid tumors, were compared for sensitivity to cytotoxic drugs and resistance modulators (RMs). The LI00 cells showed pronounced sensitivity to the RMs verapamil (Ver), cyclosporin A (CsA) and buthionine sulfoximine (BSO) alone as well as to cisplatinum, whereas the L0 and ACHN cells, also slowly growing fibroblasts and non-proliferating lymphocytes, were considerably less sensitive. Compared with AML cells and lymphocytes, CLL cells were more sensitive to Ver and CsA alone. The cytotoxicity of Vcr was significantly increased in the Vcr-resistant ACHN and LI00, but also in sensitive L0 cells by Ver and CsA, with smaller effects on Dox and Vp-16 toxicity. Fibroblasts and lymphocytes were generally resistant to the cytotoxic agents and RM addition had only minor effects. CLL cells were more sensitive to Dox and Vcr as compared with normal lymphocytes, with potentiation of the Vcr effect by Ver and CsA. The Vcr effect in non-proliferating Vcr-resistant cells from a malignant schwannoma was potentiated by Ver and CsA, which had no effect in cells from a kidney adenocarcinoma. We conclude that cytotoxicity of RMs alone is not dependent on the proliferation rate of tumor cells and that potentiation of cytotoxic drugs by RMs may be selective for tumor cells irrespective of their initial level and mode of drug resistance.

Exacerbation of Doxorubicin Toxicity by Chlorpromazine in Male ddY Mice

Wc examined whether chlorpromazine (CPZ) modulates the lethality of doxorubicin (DOX, 12 mg/kg, i.p.) in mice treated with CPZ (6 mg/kg, i.p.) 1 hr before administration of DOX. Pretreatment with CPZ produced: 1) earlier deaths and 2) an increase in the number of deaths, compared to the controls. Potentiation of the bone marrow toxicity of DOX by CPZ was also reflected in the drug lethality towards the animals.

Exacerbation of Doxorubicin Toxicity by Chlorpromazine in Male ddY Mice.

We examined whether chlorpromazine (CPZ) modulates the lethality of doxorubicin (DOX, 12 mg/kg, i.p.) in mice treated with CPZ (6 mg/kg, i.p.) 1 hr before administration of DOX. Pretreatment with CPZ produced: 1) earlier deaths and 2) an increase in the number of deaths, compared to the controls. Potentiation of the bone marrow toxicity of DOX by CPZ was also reflected in the drug lethality towards the animals.

The role of oxygen-derived free radicals in the cytotoxicity of doxorubicin in multidrug resistant and sensitive human ovarian cancer cells

The role of oxygen-derived free radicals in the cytotoxicity of doxorubicin (Dox) was studied in a Dox sensitive human ovarian cancer cell line (A2780) and its multidrug resistant counterpart (2780 AD) using reactive oxygen scavengers. In both cell lines, a significant inhibition of Dox toxicity was found after treatment with the hydroxyl radical scavengers, N-acetylcysteine, sodium benzoate and dimethyl sulfoxide, but not with mannitol. The protection was similar in sensitive and resistant cells: 13–39% less growth inhibition was found at Dox concentrations of 0.2 and 0.5 μM for A2780 as well as at 20 and 50 μM for 2780 AD. This protection was not due to effects of the scavengers on Dox accumulation, as shown by uptake experiments with radio-labelled Dox. The superoxide anion free radical scavenger ascorbic acid or the enzyme superoxide dismutase as well as the hydrogen peroxide scavenger catalase did not protect cells against Dox-induced cell growth inhibition. Preloading the cells with the enzymes, a treatment which resulted in a two to nine-fold increase in their cellular contents, was not effective either. It is concluded that hydroxyl radicals, but not superoxide anion or hydrogen peroxide likely play a role in the antitumor activity of Dox in sensitive and resistant human ovarian cancer cells.