Antitumor Efficacy Of Doxorubicin Research Articles

Multi-functionalized single-walled carbon nanotubes as delivery carriers: promote the targeting uptake and antitumor efficacy of doxorubicin

Multi-functionalized single-walled carbon nanotubes as delivery carriers: promote the targeting uptake and antitumor efficacy of doxorubicin

PEGylated phospholipid micelles containing D-α-tocopheryl succinate as multifunctional nanocarriers for enhancing the antitumor efficacy of doxorubicin

The aim of this investigation is to clarify the effect of D-α-tocopheryl succinate (vitamin E succinate, VES) and distearoylphosphatidyl ethanolamine-poly(ethylene glycol) (DSPE-PEG) on the encapsulation and controlled release of doxorubicin (DOX) in nano-assemblies and their consequences on the anti-tumor efficacy of DOX. DOX molecules were successfully loaded into the hybrid micelles with VES and DSPE-PEG (VDPM) via thin-film hydration method, exhibiting a small hydrodynamic particle size (~30 nm) and a weak negative zeta potential of around −5 mv. The obtained DOX-loaded VDPM2 displayed retarded DOX release at pH of 7.4, while substantially accelerated drug release at acidic pH of 5.0. Furthermore, the DOX-loaded VDPM2 exhibited substantially slower drug release rate at pH 7.4 compared with the drug-loaded VDPM1 or DPM preparation, benefiting for decreasing the premature DOX release during blood circulation. In vitro cell experiment indicated that DOX-loaded micelles (DPM, VDPM1 and VDPM2) improved the cellular uptake of DOX in 4T1 and MDA-MB-231 cells. The existence of VES component in the structure of DOX-loaded micelles had no obvious influence on the subcellular distribution of the encapsulated DOX molecules. Furthermore, the DOX-loaded VDPM2 exhibited more pronounced cytotoxicity to 4T1 and MDA-MB-231 cancerous cells compared with DOX-loaded DPM and free DOX solution. The hybrid nanocarriers including VES and DSPE-PEG selectively induced intracellular ROS accumulation and increased level of cytoplasmic calcium ion in cancerous cells by interacting with mitochondria and endoplasmic reticulum, bringing about the improved cytotoxicity of DOX. In vivo antitumor efficacy investigation of DOX-loaded VDPM2 against 4T1 xenograft-bearing mice displayed satisfied therapeutic activity with negligible systemic toxicity, as evidenced by the histological analysis and change of body weight. The proposed DOX-loaded VDPM preparation, as a mulifunctional chemotherapeutic nanomedicine system, holds great potential and bright prospect for clinical tumor therapy.

Evaluation of antitumor efficacy of folate-poly(2-ethyl-2-oxazoline)-distearoyl phosphatidyl ethanolamine based liposome

This study aims to explore and evaluate the antitumor efficacy of doxorubicin (DOX)-loaded liposomes containing the novel tri-block polymer folate-poly (2-ethyl-2-oxazoline)-distearoyl phosphatidyl ethanolamine (F-PEOz-DSPE), compared with folate-polyethylene glycol-distearoyl phosphatidyl ethanolamine (F-PEG-DSPE) to offer an alternative for PEG decorated carriers. PEOz, a pH-sensitive polymer, exhibits similar solubility and segmental flexibility to PEG. In our previous study, PEOz was employed to an F-PEOz-DSPE which was segmentally similar to F-PEG-DSPE and exhibited selective targeting and pH-sensitivity in tumor cells. In this work, DOX-loaded liposomes containing F-PEOz-DSPE (F-PEOz liposome) or F-PEG-DSPE (F-PEG liposome) were prepared. In vivo/vitro antitumor efficacy and biodistribution were compared between the two liposomes. F-PEOz liposome showed higher in vitro antitumor activity and significantly stronger inhibition of tumor growth in HeLa tumor-bearing nude mice (tumor inhibition rate, 81.20 vs 52.99% with the treatment of 9 mg/kg DOX-loaded F-PEOz liposome/F-PEG liposome) and much less toxicity than free DOX. In vivo fluorescence imaging experiment confirmed that F-PEOz liposome accumulated much more than F-PEG liposome in tumor. Based on the above, F-PEOz liposome may be a promising carrier in tumor chemotherapy to achieve better therapeutic efficacy.

Co-delivery of curcumin and doxorubicin in PEGylated liposomes favored the antineoplastic C26 murine colon carcinoma microenvironment.

Our recent studies have demonstrated that the antitumor efficacy of doxorubicin (DOX), administered in long-circulating liposomes (LCL), could be considerably improved after its co-encapsulation with curcumin (CURC). Thus, the question addressed within this article is whether LCL-CURC-DOX can be exploited more efficiently than liposomal DOX for future colorectal cancer therapy. Therefore, we investigated the physicochemical and biological properties of LCL-CURC-DOX and the mechanisms of its antitumor activity in C26 murine colon carcinoma in vivo. Our results proved that the developed nanoformulation based on the co-encapsulation of CURC and DOX met the requirements of a modern drug delivery system for future cancer therapy, demonstrating enhanced antitumor activity on C26 colon carcinoma in vivo. The antitumor efficacy of LCL-CURC-DOX relied on suppressive effects on main protumor processes such as angiogenesis, inflammation, oxidative stress, invasion and resistance to apoptosis, and on the dysregulation of Th1/Th2 cell axis which favored the antineoplastic phenotype of cells in tumor microenvironment (TME). The development of multitargeted strategies aiming at stimulating antitumor effects within the tumor milieu and counteracting the escape mechanisms of cancer cells would be beneficial in the management of colon cancer in the future.

Reducing doxorubicin cardiotoxicity in rats with mammary tumors by dantrolene.

e12013 Background: Doxorubicin (DOX), widely used in breast cancer, is known for its cardiotoxicity. Preventing DOX-cardiotoxicity without affecting its antitumor efficacy has not been successful. DOX-cardiotoxicity results from oxidative stress that increases intracellular calcium levels by promoting the release of Ca2+ from sarcoplasmic reticulum (SR) and impairing Ca2+ clearance in cardiomyocytes. Dantrolene (DNT), a postsynaptic muscle relaxant inhibits the release of Ca2+ from SR by inhibiting the ryanodine receptor (RYR). The aim of this study was to examine the effect of DNT on cardiotoxicity and anti-tumor efficacy of DOX in a rat model of breast cancer. Methods: Female F344 rats with implanted MatBIII breast cancer cells were randomized into 3 groups of 12 rats/group and were treated as follows: “DOX” group was injected i.p. with DOX 2x week for 3 weeks (cumulative dose 12 mg/kg); “DNT” group received daily DNT (5mg/kg/day) by oral gavage; and “DOX+DNT” group was treated with DOX 2x week for 3 weeks and daily DNT (5mg/kg). The presence of cardiac alterations was examined by echocardiography before and after the experiment. Body weight, tumor size and volume were measured at sacrifice. H&E stainings of the hearts and tumors was examined. Blood glutathione (GSH) levels were determined. Results: Mortality in the groups of rats treated with DOX alone, DNT+DOX and DNT was 40%, 16% and 0%, respectively. Histopathologic analysis of hearts of the surviving rats showed reduced DOX induced cardiotoxicity in the group treated with DOX+DNT as shown by reduced interstitial edema, cytoplasmic vacuolization and myofibrilar dysruption, compared to DOX only treated hearts. DNT significantly increased cardiac output and stroke volume, and improved the decline of left ventricle ejection fraction (LVEF) induced by DOX by 50%. Also, reduced breast tumor volumes with increased tumor necrosis was observed in rats treated with DOX+DNT compared to DOX alone. Rats treated with DNT lost less body weight and had a higher blood GSH levels. Conclusions: These data indicate that DNT is able to provide protection against DOX cardiotoxicity while maintaining its antitumor efficacy. Further preclinical studies are needed to determine the optimal dosing of DNT.

Targeted polyethylene glycol gold nanoparticles for the treatment of pancreatic cancer: from synthesis to proof-of-concept in vitro studies

The main objective of this study was to optimize and characterize a drug delivery carrier for doxorubicin, intended to be intravenously administered, capable of improving the therapeutic index of the chemotherapeutic agent itself, and aimed at the treatment of pancreatic cancer. In light of this goal, we report a robust one-step method for the synthesis of dicarboxylic acid-terminated polyethylene glycol (PEG)-gold nanoparticles (AuNPs) and doxorubicin-loaded PEG-AuNPs, and their further antibody targeting (anti-Kv11.1 polyclonal antibody [pAb]). In in vitro proof-of-concept studies, we evaluated the influence of the nanocarrier and of the active targeting functionality on the anti-tumor efficacy of doxorubicin, with respect to its half-maximal effective concentration (EC50) and drug-triggered changes in the cell cycle. Our results demonstrated that the therapeutic efficacy of doxorubicin was positively influenced not only by the active targeting exploited through anti-Kv11.1-pAb but also by the drug coupling with a nanometer-sized delivery system, which indeed resulted in a 30-fold decrease of doxorubicin EC50, cell cycle blockage, and drug localization in the cell nuclei. The cell internalization pathway was strongly influenced by the active targeting of the Kv11.1 subunit of the human Ether-à-go-go related gene 1 (hERG1) channel aberrantly expressed on the membrane of pancreatic cancer cells. Targeted PEG-AuNPs were translocated into the lysosomes and were associated to an increased lysosomal function in PANC-1 cells. Additionally, doxorubicin release into an aqueous environment was almost negligible after 7 days, suggesting that drug release from PEG-AuNPs was triggered by enzymatic activity. Although preliminary, data gathered from this study have considerable potential in the application of safe-by-design nano-enabled drug-delivery systems (ie, nanomedicines) for the treatment of pancreatic cancer, a disease with a poor prognosis and one of the main current burdens of today’s health care bill of industrialized countries.

Sildenafil (Viagra) sensitizes prostate cancer cells to doxorubicin-mediated apoptosis through CD95.

We previously reported that Sildenafil enhances apoptosis and antitumor efficacy of doxorubicin (DOX) while attenuating its cardiotoxic effect in prostate cancer. In the present study, we investigated the mechanism by which sildenafil sensitizes DOX in killing of prostate cancer (PCa) cells, DU145. The death receptor Fas (APO-1 or CD95) induces apoptosis in many carcinoma cells, which is negatively regulated by anti-apoptotic molecules such as FLIP (Fas-associated death domain (FADD) interleukin-1-converting enzyme (FLICE)-like inhibitory protein). Co-treatment of PCa cells with sildenafil and DOX for 48 hours showed reduced expression of both long and short forms of FLIP (FLIP-L and -S) as compared to individual drug treatment. Over-expression of FLIP-s with an adenoviral vector attentuated the enhanced cell-killing effect of DOX and sildenafil. Colony formation assays also confirmed that FLIP-S over-expression inhibited the DOX and sildenafil-induced synergistic killing effect as compared to the cells infected with an empty vector. Moreover, siRNA knock-down of CD95 abolished the effect of sildenafil in enhancing DOX lethality in cells, but had no effect on cell killing after treatment with a single agent. Sildenafil co-treatment with DOX inhibited DOX-induced NF-κB activity by reducing phosphorylation of IκB and nuclear translocation of the p65 subunit, in addition to down regulation of FAP-1 (Fas associated phosphatase-1, a known inhibitor of CD95-mediated apoptosis) expression. This data provides evidence that the CD95 is a key regulator of sildenafil and DOX mediated enhanced cell death in prostate cancer.

Abstract 252: Doxorubicin-induced H9c2 Cell Death is Mediated by Excessive Mitochondrial Fission and Mitophagy

Doxorubicin (DOX) is a widely used antineoplastic agent that can cause heart failure. DOX cardiotoxicity is closely associated with mitochondrial damage. Mitochondrial fission and mitophagy are quality control mechanisms that help maintain a pool of healthy mitochondria. However, too much mitochondrial fission and/or mitophagy may compromise cell viability. Indeed, Mdivi-1, an inhibitor of the fission protein Drp1, can attenuate DOX-induced cardiac injury, suggesting that mitochondrial fragmentation may play a role in DOX cardiotoxicity. Using genetic gain- and loss-of function approaches, we determined whether mitochondrial fragmentation and/or mitophagy contribute to DOX-induced cardiomyocyte death. H9c2 cardiac myoblast cells were transfected with siRNA targeting Drp-1 before DOX administration. Mitochondrial morphology was examined with confocal microscopy after infection of the cells with the adenovirus encoding mitochondria-targeted fluorescent protein MitoDsRed. Morphometric analysis demonstrated that Drp-1 knockdown markedly diminished DOX-induced mitochondrial fragmentation as shown by form factor, aspect ratio, and mean mitochondrial size. This led to reduced cardiomyocyte death as revealed by the percentage of propidium iodide (PI)-positive cells and the cleavage of caspase-3 and Poly ADP ribose polymerase (PARP). Not surprisingly, Drp-1 knockdown also attenuated DOX-induced mitophagy flux as assessed by the dual fluorescent mitophagy reporter mt-Rosella. Further, knockdown of Parkin, a key regulator of mitophagy, dramatically diminished DOX-induced H9c2 cell death. Although Drp1 overexpression did not markedly increase DOX-induced cell death, Parkin overexpression predisposed H9c2 cells to DOX toxicity. Together, these results suggest that DOX-induced cardiotoxicity may be due to excessive mitochondrial fragmentation and accelerated mitochondrial degradation through autophagy. Strategies that limit mitochondrial fission and mitophagy within the physiological range may help reduce DOX cardiotoxicity. However, further studies are clearly warranted to make sure that these strategies will not compromise the antitumor efficacy of DOX.

Abstract P055: 2-Deoxy-Glucose Reduces Doxorubicin Cardiotoxicity in Tumor-Bearing Mice

Doxorubicin (DOX) is a potent, commonly used anthracycline antibiotic for a wide range of cancers, but its dose is limited by its strong cardiotoxic effects. The glucose analog 2-deoxy-D-glucose (2-DG) has been shown to enhance the antitumor efficacy of DOX in tumor cell lines and in animals. However, the cardiac effects of 2-DG in these experiments were not determined. In the current study, we examined whether 2-DG could protect from DOX cardiotoxicity in a BALB/c mouse breast cancer model. A total of 32 mice were injected with 10 5 4T1 mouse mammary epithelial tumor cells in the right hind leg. The tumor was allowed to progress for 1 week before dividing the mice into four groups: saline, 2-DG, DOX, and 2-DG with DOX treatment. 2-DG was given 150 mg/kg i.p. Monday through Friday; DOX was given 5 mg/kg i.p. Wednesday. The study was conducted for 3 weeks and echocardiography was performed the day before sacrifice. Two of the eight mice in the DOX group died before echocardiography, while none died in the 2-DG with DOX group. Echocardiography indicated similar cardiac function between saline and 2-DG groups as measured by fractional shortening (36.3±1.31% vs 37.7±0.942%, p>0.05). DOX markedly reduced cardiac function, which was almost completely recovered by 2-DG (25.1±1.06% vs 36.7±1.76%, p<0.01). Serum CK-MB content, a common clinical marker for heart damage, was increased ~6 fold in the DOX group (67.5±19.4 vs 400±145, p<0.023). 2-DG tended to reduce DOX-triggered CK-MB release, but it did not reach significant levels likely due to the small sample size and high variation (279±68.7 vs 400±145, p>0.05). Nonetheless, 2-DG largely eliminated DOX-induced apoptosis in the heart as shown by a DNA laddering assay. 2-DG or DOX alone increased cardiac autophagic flux as measured by the difference in LC3-II protein levels in the absence and presence of the lysosomal inhibitor, bafilomycin A1. Paradoxically, autophagic flux was not notably elevated when mice were treated with 2-DG and DOX simultaneously. These results demonstrate the ability of 2-DG to reduce DOX cardiotoxicity without affecting its antitumor activity, suggesting that 2-DG can improve the therapeutic window for DOX, allowing greater flexibility in designing different regimens for treating cancers.

Green tea catechins augment the antitumor activity of doxorubicin in an in vivo mouse model for chemoresistant liver cancer

Green tea catechins have been reported to have antitumor activity. The objective of this study was to examine the effect of catechins on the antitumor efficacy of doxorubicin (DOX) in a murine model for chemoresistant hepatocellular carcinoma (HCC). Epicatechin gallate (ECG) and epigallocatechin gallate (EGCG) are the most abundant polyphenolic compounds in green tea. Here, we show that ECG or EGCG at higher doses had a slight inhibitory effect on cell proliferation in the resistant human HCC cell line BEL-7404/DOX in vitro and in vivo, whereas the administration of DOX with these compounds at lower doses significantly inhibited HCC cell proliferation in vitro and hepatoma growth in a xenograft mouse model, compared with treatment with either agent alone at the same dose. Furthermore, the administration of DOX in combination with ECG or EGCG markedly enhanced intracellular DOX accumulation, which implies that the catechins inhibited P-glycoprotein (P-gp) efflux pump activity. Consistent with these results, the intracellular retention of rhodamine 123, a P-gp substrate, was increased and the level of P-gp was decreased in cells concurrently treated with DOX and ECG or EGCG. EGCG increased topo II expression, but did not alter GST protein levels in tumor xenografts. The expression of MDR1 and HIF-1alpha mRNA was obviously reduced, whereas MRP1 and LRP expression was not changed significantly. These data suggest that tea catechins at non-toxic doses can augment DOX-induced cell killing and sensitize chemoresistant HCC cells to DOX. The chemosensitizing effect of catechins may occur directly or indirectly by reversal of multidrug resistance, involving the suppression of MDR1 expression, or by enhancement of intracellular DOX accumulation, involving inhibition of P-gp function.

Fever-range whole body hyperthermia increases the number of perfused tumor blood vessels and therapeutic efficacy of liposomally encapsulated doxorubicin

Purpose: Two major questions were addressed: (1) Can fever-range whole body hyperthermia (FR-WBH) affect the number of perfused tumor blood vessels? (2) Can pre-treatment with FR-WBH improve accumulation or anti-tumor efficacy of doxorubicin or DOXIL (liposomal doxorubicin)?Materials and methods: Perfused blood vessels were visualized by intravenous injection of the fluorescent dye (DiOC7(3)) and the number of labeled vessels in tumors and normal organs of unheated mice and those previously heated to 39.5°C for 6 hours were compared. Using three animal tumor models (one syngeneic murine model and two human tumor xenografts in SCID mice) we also compared tumor growth and amount of intratumoral doxorubicin (given as free drug or as DOXIL) in control mice or those given pre-treatment with FR-WBH.Results: FR-WBH had no effect on the number of CD-31 labeled blood vessels. However, in tumors, but not in normal organs of the same animals, FR-WBH resulted in a significant increase in those blood vessels which could take up dye over a prolonged period of time after heating. There was also an increase in DOXIL uptake in the tumors of mice given FR-WBH prior to drug injection as well as enhanced therapeutic efficacy in all three tumor models.Conclusions: FR-WBH increases the number of perfused blood vessels in tumors over a prolonged period following FR-WBH and thus may be useful for improving tumor targeting of cancer therapeutics. We discuss these data in relation to long-conserved thermoregulatory features in normal vasculature, which may be deficient in tumor vasculature.

Effects of Exercise Training on Antitumor Efficacy of Doxorubicin in MDA-MB-231 Breast Cancer Xenografts

Exercise is becoming readily accepted as a beneficial adjunct therapy to maintain or enhance quality of life in breast cancer patients undergoing adjuvant chemotherapy. An essential precursor to these studies is to investigate whether exercise modulates the antitumor efficacy of chemotherapeutic agents. Athymic female mice were transplanted with MDA-MB-231 breast xenografts and randomly assigned to one of four groups (n = 21 per group): (a) control, (b) exercise-only, (c) doxorubicin-only, or (d) exercise + doxorubicin. Exercise groups performed progressive treadmill running up to 18 m/min at 0% grade for 45 minutes, 5 d/wk for 8 weeks. Tumor growth delay was significantly longer in the doxorubicin-only and exercise + doxorubicin groups compared with the control (median 42 versus 25 days, P = 0.0082; 36 versus 25 days, P = 0.029, respectively) and exercise-only groups (median 42 versus 25 days, P = 0.029; 36 versus 25 days, P = 0.080, respectively). There was no significant difference between the doxorubicin-only and exercise + doxorubicin groups (median 42 versus 36 days, P = 0.33), suggesting that moderate intensity exercise does not significantly influence doxorubicin-induced tumor growth delay. These studies are essential to fully understand the safety and application of exercise as a supportive intervention in cancer control.

Antitumor Efficacy of Doxorubicin in Combination with Cisplatin on Human Lymphoma Cells at Various Cell Densities in vitro.

The influence of tumor cell density on the antitumor effect of doxorubicin (DXR) in combination with cisplatin (CDDP) was studied in vitro using DND-39A lymphoma cells. DXR was progressively less effective on colony formation inhibition when cell density was increased from 10(5) to 10(8) viable cells/ml (positive inoculum effect), whereas the effect of CDDP was not influenced by cell densities. At a density of 10(5) cells/ml, inhibition of colony formation was virtually identical irrespective of cells being exposed to DXR and CDDP either simultaneously or sequentially. When cell density was increased to 10(7) and 10(8) cells/ml, sequential exposure to CDDP followed by DXR was more active than simultaneous or reversed order of exposure to the two drugs. These results indicate that for DXR-CDDP combination chemotherapy against the cells at high density, the proper sequence of the treatment should be the administration of CDDP followed by DXR, rather than simultaneous or reversed order of exposure. Inoculum effect may be an additional determinant for the rational development of combination chemotherapy.

Analysis of the effect of liposome encapsulation on the vesicant properties, acute and cardiac toxicities, and antitumor efficacy of doxorubicin

Numerous studies have demonstrated that liposomal encapsulation decreases the life-threatening chronic and acute toxicities of doxorubicin in the face of unaltered or improved antitumor activity. Minimal attention has been paid to the encapsulation effect on the lesser toxicities of the drug, specifically the vesicant properties. In this report we assess the effect of the encapsulation of doxorubicin in an egg-yolk phosphatidylcholine (EPC) cholesterol liposome on the drug's topical toxicity. In addition, to ensure acceptable activity and reduction in toxicity comparable with those of previously assessed formulations, the cardiac and acute toxicities and antitumor activity of the liposomal doxorubicin complex were also investigated. Antitumor efficacy was assessed using the metastatic murine P815 mastocytoma model. Equivalent doses of free and encapsulated doxorubicin possessed the same antitumor activity in the prolongation of animal survival in 14-day survival studies conducted to assess the effect of liposomal encapsulation on the acute toxicity of this drug. The LD50 of liposomal doxorubicin was found to be 40 mg/kg, 53% higher than that of free doxorubicin (26 mg/kg). Histologic examination of cardiac sections taken from DBA/2J mice 7 days after a single i.v. injection of free or liposomal doxorubicin (25 mg/kg) revealed that the liposomal preparation was much less cardiotoxic. In animals receiving the free drug, edema, monocytic infiltration, and cell necrosis were evident. In contrast, those receiving the liposomal preparation demonstrated slight cellular edema but showed no evidence of cellular necrosis. To assess vesicant properties, DBA/2J mice were given a single s.c. injection (0.2 ml) of free or liposomal doxorubicin (2 mg/ml). Those receiving the free drug immediately developed erythema and edema at the injection site, which progressed to ulceration. Those receiving the liposomal complex developed slight erythema and edema but did not ulcerate at any time. All signs of irritation in this group had subsided 3 weeks postinjection. In summary, the liposomal complex used eliminated the vesicant properties of doxorubicin as well as significantly decreasing its cardiac and acute toxicities in the face of unaltered antitumor activity.