Doxorubicin Levels Research Articles

Comparison of pharmacokinetics, tissue distribution and pharmacodynamics of liposomal and free doxorubicin in tumour-bearing mice following intratumoral injection

The clinical application of doxorubicin (DOX) is limited by severe systemic side effects. The aim of this study was to develop a strategy that combined the liposomal DOX (LipDOX) and intratumoral injection to reduce the toxicity and enhance the antitumor efficiency. The pharmacokinetics, tissue distribution and pharmacodynamics of LipDOX compared with free DOX were investigated by intratumoral injection in murine H22 hepatoma-bearing mice at a dose of 20 mg/kg body weight. A sensitive HPLC-tandem mass spectrometry method was used to determine the DOX levels in plasma and tissues. The tumour volume and body weight of mice were measured every 3 days. LipDOX administration resulted in 1.3-fold longer mean residence time (MRT) and 2.4-fold higher area under concentration (AUC)-time curve compared with free DOX administration in tumour. Free DOX caused higher peak plasma concentration (Cmax ) than LipDOX in plasma and major organs, which may result in significant mortality for acute cardiac toxicity. After successive 21 days treatment, the final volume of tumour treated by normal saline, free DOX and LipDOX was 5.0-, 1.3-fold higher and 1.6-fold lower than the initial tumour volume, respectively. Our results indicated that the intratumoral injection of LipDOX is a promising approach with higher therapeutic efficacy and lower systemic toxicity than free DOX.

Systemic anti-tumour effects of local thermally sensitive liposome therapy

Purpose: There were two primary objectives of this study: (1) to determine whether treatment of a tumour site with systemically administered thermally sensitive liposomes and local hyperthermia (HT) for triggered release would have dual anti-tumour effect on the primary heated tumour as well as an unheated secondary tumour in a distant site, and (2) to determine the ability of non-invasive optical spectroscopy to predict treatment outcome. The optical end points studied included drug levels, metabolic markers flavin adenine dinucleotide (FAD), nicotinamide adenine dinucleotide phosphate (NAD(P)H), and physiological markers (total haemoglobin (Hb) and Hb oxygen saturation) before and after treatment.Materials and methods: Mice were inoculated with SKOV3 human ovarian carcinoma in both hind legs. One tumour was selected for local hyperthermia and subsequent systemic treatment. There were four treatment groups: control, DOXIL® (non-thermally sensitive liposomes containing doxorubicin), and two different thermally sensitive liposome formulations containing doxorubicin. Optical spectroscopy was performed prior to therapy, immediately after treatment, and 6, 12, and 24 h post therapy.Results: Tumour growth delay was seen with DOXIL and the thermally sensitive liposomes in the tumours that were heated, similar to previous studies. Tumour growth delay was also seen in the opposing tumour in the thermally sensitive liposome-treated groups. Optical spectroscopy demonstrated correlation between growth delay, doxorubicin (DOX) levels, and changes of NAD(P)H from baseline levels. Hb and Hb saturation were not correlated with growth delay.Discussion: The study demonstrated that thermally sensitive liposomes affect the primary heated tumour as well as systemic efficacy. Non-invasive optical spectroscopy methods were shown to be useful in predicting efficacy at early time points post-treatment.

HIGH INTERSTITIAL FLUID PRESSURE REGULATES TUMOR GROWTH AND DRUG UPTAKE IN HUMAN GLIOBLASTOMA

BACKGROUND: (blind field). METHODS: We developed methodology to measure IFP in human GBM xenografts and mechanical compression in 3D-cultures. We used a cell counter and calcein-AM-loaded cells to measure cell volume following treatment with temozolomide and/or blockade of NKCC1 activity. Fluorescent MQAE-loaded cells were recorded to measure intracellular chloride levels. To study uptake of chemotherapy following IFP-reduction in GBM xenografts following AF-induction or treatment with bumetanide, we injected doxorubicin and measured fluorescent doxorubicin levels in tissue sections. RESULTS: Elevated compression increased proliferation in GBM cultures and IFP levels rapidly increased during the exponential growth phase in GBM xenografts. In contrast to Avastin that targets the vasculature, SPC diet induced AF expression only in tumor cells. In addition to reducing IFP levels, AF-induction also inhibited proliferation, induced apoptosis, and increased survival in mice xenografted with human GBM cells. SPC diet and intranasal injection of AF increased uptake of doxorubicin in GBM xenografts. In vitro, AF augmented TMZ-induced apoptosis and reduced proliferation at both baseline and increased hydrostatic compression. CONCLUSIONS: In contrast to IFP-reducing therapies targeting the vasculature, treatments that reduced osmotic pressure in GBM cells effectively reduced tumor growth and invasion in vivo. AF and bumetanide increased uptake and cytotoxic response from chemotherapies by inhibiting NKCC1 activity in GBM cells. Our studies suggest that elevated IFP promotes tumor growth, reduces drug uptake, and limits therapy-response in GBM. AF-induction represents an attractive strategy to reduce invasion, inhibit tumor growth, increase drug uptake, and ultimately improve the survival of GBM patients. SECONDARY CATEGORY: Preclinical Experimental Therapeutics.

Inhibited effects of veliparib combined doxorubicin for BEL-7404 proliferation of human liver cancer cell line

ObjectiveTo explore inhibition effects of veliparib as PARP inhibitor combined doxorubicin for BEL-7404 proliferation of human liver cancer cell line. MethodsBEL-7404 was taken as the object of study and conventional culture was performed. It wastreated by doxorubicin and (or) veliparib after 24 h. Cell proliferation rate was detected by four methyl thiazolyl tetrazolium (MTT) assay, cell apoptosis was measured with annexin V-FITC/PI double staining method by flow cytometry, DNA damage degree evaluation by single cell gel electrophoresis assay, and cytosolic C levels of the mitochondrial and cytosol by polyacrylamide gel electrophoresis (Western blotting). ResultsCell proliferation rate of doxorubicin combined veliparib group was lower than that of the control group and doxorubicin alone treated group significantly (P<0.01), the apoptosis rate was significantly higher than that of the control group and doxorubicin alone treated group (P<0.05). At the same time, DNA damage level of doxorubicin combined with veliparib group was significantly higher than doxorubicin alone treatment group and the control group (P<0.01), and cytochrome C in the cytosol was significantly higher than that of control group and doxorubicin alone treated group (P<0.01). ConclusionsVeliparib, PARP inhibitor could inhibit PARP activity, block tumor cell DNA repair, and have significant sensitizing effect for hepatocellular carcinoma cell line BEL-7404 treated with doxorubicin. This might provide a new target for clinical treatment of hepatic carcinoma.

In vivo disposition of doxorubicin is affected by mouse Oatp1a/1b and human OATP1A/1B transporters

Organic anion-transporting polypeptides (OATPs) are important drug uptake transporters, mediating distribution of substrates to several pharmacokinetically relevant organs. Doxorubicin is a widely used anti-cancer drug extensively studied for its interactions with various drug transporters, but not OATPs. Here, we investigated the role of OATP1A/1B proteins in the distribution of doxorubicin. In vitro, we observed ∼ 2-fold increased doxorubicin uptake in HEK293 cells overexpressing human OATP1A2, but not OATP1B1 or OATP1B3. In mice, absence of Oatp1a/1b transporters led to up to 2-fold higher doxorubicin plasma concentrations and 1.3-fold higher plasma AUC. Conversely, liver AUC and liver-to-plasma ratios of Oatp1a/1b(-/-) mice were 1.4-fold and up to 4.1-fold lower than in wild-type mice, respectively. Decreased doxorubicin levels in the small intestinal content reflected those in the liver, indicating a reduced biliary excretion of doxorubicin in Oatp1a/1b(-/-) mice. These results demonstrate important control of doxorubicin plasma clearance and hepatic uptake by mouse Oatp1a/1b transporters. This is unexpected, as the fairly hydrophobic weak base doxorubicin is an atypical OATP1A/1B substrate. Interestingly, transgenic liver-specific expression of human OATP1A2, OATP1B1 or OATP1B3 could partially rescue the increased doxorubicin plasma levels of Oatp1a/1b(-/-) mice. Hepatic uptake and bile-derived intestinal excretion of doxorubicin were completely reverted to wild-type levels by OATP1A2, and partially by OATP1B1 and OATP1B3. Thus, doxorubicin is transported by hepatocyte-expressed OATP1A2, -1B1 and -1B3 in vivo, illustrating an unexpectedly wide substrate specificity. These findings have possible implications for the uptake, disposition, therapy response and toxicity of doxorubicin, also in human tumors and tissues expressing these transporters.

Tumor Vasculature-Targeted Recombinant Mutated Human TNF-α Enhanced the Antitumor Activity of Doxorubicin by Increasing Tumor Vessel Permeability in Mouse Xenograft Models

ObjectiveIncreasing evidence suggests that, when used in combination, tumor necrosis factor-α (TNF-α) synergizes with traditional chemotherapeutic drugs to exert a heightened antitumor effect. The present study investigated the antitumor efficacy of recombinant mutated human TNF-α specifically targeted to the tumor vasculature (RGD-rmhTNF-α) combined with the chemotherapeutic agent doxorubicin in 2 murine allografted tumor models.MethodsMice bearing hepatoma or sarcoma allografted tumors were treated with various doses of RGD-rmhTNF-α alone or in combination with doxorubicin (2 mg/kg). We then evaluated tumor growth and tumor vessel permeability as well as intratumoral levels of RGD-rmhTNF-α and doxorubicin.ResultsRGD-rmhTNF-α treatment enhanced the permeability of the tumor vessels and increased intratumoral doxorubicin levels. In addition, intratumoral RGD-rmhTNF-α levels were significantly higher than that of rmhTNF-α. In both of the tested tumor models, administering RGD-rmhTNF-α in combination with doxorubicin resulted in an enhanced antitumor response compared to either treatment alone. Double-agent combination treatment of doxorubicin with 50,000 IU/kg RGD-rmhTNF-α induced stronger antitumor effects on H22 allografted tumor-bearing mice than the single doxorubicin agent alone. Moreover, doxorubicin with 10,000 IU/kg RGD-rmhTNF-α synergized to inhibit tumor growth in S180 allografted tumor-bearing mice.ConclusionsThese results suggest that targeted delivery of low doses of RGD-rmhTNF-α into the tumor vasculature increases the antitumor efficacy of chemotherapeutic drugs.

Epigallocatechin-3-gallate potentiates the effect of curcumin in inducing growth inhibition and apoptosis of resistant breast cancer cells.

Drug resistance remains an on-going challenge in breast cancer chemotherapy. Combination of two or more drugs is an effective strategy to access context-specific multiple targets and overcome undesirable toxicity that is almost inevitable in single-drug chemotherapy. Many plant food-derived polyphenolic compounds have been proven to modulate many key factors responsible for cancer drug resistance, which makes them a promising group of low toxicity candidates for reversing cancer resistance. In this study, we analyzed the combination effect of two chemopreventive polyphenols, curcumin (Cur) and epigallocatechin-3-gallate (EGCG), in combating resistant breast cancer. Our present results showed that EGCG significantly enhanced the growth inhibition and apoptosis in both doxorubicin (DOX)-sensitive and resistant MCF-7 cells induced by Cur. The mechanism may be related to the further activation of caspase-dependent apoptotic signaling pathways and the enhanced cellular incorporation of Cur by inhibiting P-glycoprotein (P-gp) pump function. Moreover, Cur and EGCG in combination could enhance the toxicity of DOX and increase the intracellular level of DOX in resistant MCF-7 cells. Our findings with this practical combination of Cur and EGCG encourage us to move on to a promising strategy for successful treatment of human breast cancer resistance by combining two low-toxic chemotherapeutic agents from diet.

Improvements of Doxorubicin-Induced Antitumor Activity and Adverse Reaction by Combined Citrulline

Citrulline is an amino acid with antioxidant activity. In this study, effects of citrulline on the adverse effects of doxorubicin (DOX) and DOX-induced antitumor activity were examined. Citrulline significantly inhibited DOX-induced increases in lipid peroxide (LPO) in the heart as adverse reaction. Combined treatment with DOX and citrulline increased DOX levels in tumor cells and enhanced cytotoxicity in vitro by significantly increasing DOX uptake compared with DOX treatment alone. In simultaneous in vivo treatments, combination treatment with DOX and citrulline decreased tumor weight and increased DOX concentrations in tumors. Promotion of DOX uptake by citrulline enhanced the antitumor activity of DOX through the action of energy-independent and Na(+)-independent transporters. This effect of citrulline on DOX influx is identical to that of S-(4-nitrobenzyl)-6-thioinosine, promoting DOX influx through the equilibrative nucleoside transporter 1. Therefore, it is anticipated that citrulline as a food component may enhance DOX efficacy.

Chemoembolization of Hepatocellular Carcinoma with Hepasphere 30–60 μm. Safety and Efficacy Study

BackgroundThis study examined the safety, pharmacokinetics, and efficacy of transarterial chemoembolization of hepatocellular carcinoma (HCC) using a newly developed size of a superabsorbent polymer drug-eluting embolic material.MethodsForty-five patients with documented HCC (Child–Pugh score A/B: 55.5 %/44.5 %) were embolized with HepaSphere microspheres 30–60 μm with escalation of lesion, dose, and frequency of re-embolization. Local response was evaluated with modified response evaluation criteria in solid tumors (mRECIST). Plasma levels of doxorubicin were measured in 24 patients at baseline and at 5, 20, 40, 60, and 120 min, at 6, 24, and 48 h, and at 7 days, respectively, to determine doxorubicin in plasma (Cmax) and area under the curve (AUC). Measurements of three patients who underwent lipiodol-based conventional chemoembolization (c-TACE) were also performed.ResultsTACE with HepaSphere was well tolerated with an acceptable safety profile and no 30-day mortality. Response rates were calculated on intention-to-treat basis with complete response (CR) in 17.8 % reaching 22.2 % for the target lesion. Overall partial response (PR) was seen in 51.1 %, stable disease in 20 %, and progressive disease in 11.1 % of patients. Overall objective response (CR + PR), including patients treated at all dosages of doxorubicin, was seen in 68.9 % of cases. After a median follow-up of 15.6 months, 1-year survival is 100 %. Doxorubicin AUC was significantly lower in patients with HepaSphere 30–60 μm (35,195 ± 27,873 ng × min/ml) than in patients with conventional TACE (103,960 ± 16,652 ng × min/ml; p = 0.009). Cmax was also significantly lower with HepaSphere 30–60 μm (83.9 ± 32.1 ng/ml) compared with c-TACE (761.3 ± 58.8 ng/ml; p = 0.002).ConclusionHepaSphere 30–60 μm is an effective drug-eluting embolic material with a favourable pharmacokinetic profile.

Potent Effects Of The Vascular Disrupting Agent, ASA404 (DMXAA) On The Marrow Microenvironment In Preclinical Human Leukemia and Lymphoma Models

BackgroundTumor vascular disrupting agents (VDAs) represent a novel class of anti-cancer therapeutics with the unique ability to rapidly destroy established tumor vasculature and induce ischemic necrosis. In contrast to most VDAs which are derivatives of anti-tubulin agents, ASA404 (5,6-dimethylxanthenone-4-acetic acid, DMXAA) is an unique non-steroidal anti-inflammatory VDA which induces potent host immune responses and disrupts tumor vasculature in solid tumor mouse models. MethodsThe overall aim of these studies was to examine the effects of ASA404 treatment on tumor growth in preclinical human acute myeloid leukemia (HEL, HL60) and lymphoma (Raji) xenograft models. We specifically investigated the effects of drug treatment on host immune and inflammatory responses, marrow vasculature, and initial tumor engraftment. Disease progression in vivo was measured using small animal magnetic resonance imaging and bioluminescent imaging of luciferase-transfected human tumor cells. Host cytokine and chemokine levels in the plasma and other tissues (marrow, spleen, liver) were determined by multiplex flow cytometric assays. ResultsIn local acute myeloid leukemia (HEL-luciferase) xenografts, a single dose of ASA404 (25 mg/kg) markedly enhanced tumor vascular permeability, as determined by magnetic resonance imaging at 4 hours. This was followed by vascular disruption and central necrosis at 24 hours, as determined by immunohistochemistry. In systemic leukemia xenografts, a single dose of ASA404 enhanced marrow vascular permeability and induced several-fold elevations in host chemokine levels (G-CSF, IL-6, MCP-1, KC) in circulating plasma as well as bone marrow and spleen cells (MIG, G-CSF, MIP-1alpha, IP-10). Administration of ASA404 4-24 hours prior to inoculation of human acute myeloid leukemia (HEL) or lymphoma (Raji) cells in immunodeficient mice delayed disease progression and prolonged overall survival. Continuous ASA404 treatment (20 mg/kg twice weekly) for up to three weeks in established systemic leukemia and lymphoma xenografts resulted in marrow vascular disruption and significant inhibition of tumor growth. Prolonged ASA404 treatment was associated with elevations in circulating host TNF-a levels and increased numbers of macrophages within the leukemic marrow microenvironment. Combination ASA404 and doxorubicin therapy further improved the overall survival of HEL and Raji-engrafted mice as compared with AS404 or doxorubicin alone. Quantification of doxorubicin levels by HPLC in local tumor xenografts and leukemic marrow samples revealed several-fold higher doxorubicin levels following ASA404 vs. vehicle (PBS) treatment, consistent with ASA404-mediated improvements in leukemia drug delivery. Preliminary data suggest a therapeutic benefit of combination ASA404 and cytarabine therapy in the same xenograft models. ConclusionsOur results demonstrate that ASA404 exerts anti-tumor activity in human acute myeloid leukemia and lymphoma xenografts via myriad unique effects on the marrow microenvironment. Single dose administration of ASA404 results in rapid and marked alterations in multiple host cytokine/chemokine levels in association with enhanced tumor vascular permeability and impaired in vivo leukemia cell engraftment. Prolonged drug administration leads to pronounced vascular disrupting effects and inhibition of tumor growth. Combination regimens of ASA404 with anthracycline or cytarabine lead to further improvements in anti-tumor activity and overall survival in leukemia-bearing mice. These data suggest that ASA404/DMXAA may be worthy of further clinical investigation for the treatment of aggressive hematological malignancies. Disclosures:No relevant conflicts of interest to declare.

Abstract 4343: Therapeutic efficacy of different double arms polyethyleneglycol-modified liposome containing doxorubicin on pulmonary metastasis.

Abstract [Purpose] Metastasis is responsible for most mortality in cancer therapy. Important things of metastatic treatment are not only prevention but also therapy of metastatic tumor. It was indicated that usability of liposomal doxorubicin (DOX) as drug delivery system formulation which were modified with 1,2-distearoyl-sn-glycero-3-phosphoethanolamine dipolyethyleneglycol(different double arms PEG; DDA-PEG) (DDA-LDOX). DDA-PEG had two different PEG lengths, 2000 and 500, in one molecule. In this study, the effect of DDA-LDOX was examined on pulmonary metastasis compared with 1-monomethoxy-PEG(2000)-2,3-distearoylglycerol (PEG2000-DSG) modified liposomal DOX (2000-LDOX).[Methods] The liposomal DOX was prepared by L-α-distearoylphosphatidylcholine, cholesterol, L-α-distearoylphosphatidyl-DL-glycerol and DOX (100:100:60:18 μmol). Liposomal DOX was added 7.5 μmol DDA-PEG or 15 μmol PEG2000-DSG. In anti-metastasis experiment, BDF1 mice were transplanted B16F10 melanoma cells by intravenous inoculation and each liposome (2.5 mg/kg, DOX) was injected at 20, 23 and 26 day after tumor transplantation. After 48 hr from last administration, the mice were dissected and score of pulmonary metastasis was recorded (0∼10, 0: normal). Removed tissues were determined DOX concentration by fluorescence method. In vitro, it was examined DOX uptake into B16F10 melanoma cells from each liposome. [Results and Discussion] Pulmonary metastasis scores of control and 2000-LDOX were 6.5 and 2.6, respectively. In contrast, that of DDA-LDOX was 1.0. Relative pulmonary weight (%) was correlation with metastatic score (R2=0.954) and supported pulmonary metastasis score. DOX concentration of DDA-LDOX was twice higher than that of 2000-LDOX in the lung, namely, it was proved that DDA-LDOX was easy to accumulate in the lung. Especially, it was suggested that DDA-LDOX accumulated into pulmonary metastatic site because DOX concentrations of heart, spleen and kidney were equal level in other group. In the examination of DOX uptake into tumor cells, DOX level in DDA-LDOX group was significantly higher than that in 2000-LDOX group. The data had supported high accumulation into pulmonary metastasis in vivo. In conclusion, it was suggested that DDA-LDOX was useful drug carrier for suppressed pulmonary metastasis since it could have target ability to pulmonary metastasis. Citation Format: Ikumi Sugiyama, Yasuyuki Sadzuka. Therapeutic efficacy of different double arms polyethyleneglycol-modified liposome containing doxorubicin on pulmonary metastasis. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4343. doi:10.1158/1538-7445.AM2013-4343

Abstract 3382: Formation of transient membrane channels targets doxorubicin resistance.

Abstract Poor accumulation of anti-cancer drugs in tumor cells is a major limitation in clinical cancer therapy. The main barrier for a drug to traverse through the body and reach its intracellular target is the plasma membrane. A typical (candidate) drug is therefore small, amphiphilic and of limited charge. Still, membrane traversal remains a highly inefficient and impeding process. In clinical oncology in particular there is an urgent need for new ways to improve drug efficacy and reduce toxicity. We have elucidated a mechanism that effectively accelerates membrane translocation of the stereotypical and widely used amphiphilic drug, doxorubicin. Well-defined short-chain sphingolipids, when co-inserted into the membrane, diminish the barrier for doxorubicin translocation. In vicinity of doxorubicin, the lipid analogues rapidly self-assemble at nanosecond timescale, and form a small, transient membrane channel. As a result, the doxorubicin drug readily translocates the membrane, thereby reducing the energetic barrier significantly by two-fold. Monte-Carlo based full-atom simulations revealed the structure and dynamics of channel formation at molecular detail. By means of a high-throughput screening approach of classical and targeted anti-cancer agent libraries, we identified various anti-cancer drugs in addition to doxorubicin, which share critical molecular characteristics, like defined amphiphilicity. Short-chain sphingolipids enhance cellular accumulation of these anti-cancer compounds similar to doxorubicin. Guided by these mechanistic insights, we applied the concept of facilitated doxorubicin traversal in genetically engineered WAPcre;EcadF/F;p53F/F mouse models for breast cancer. These tumors are multi-drug resistant to conventional and targeted anti-cancer agents. Co-administration of the sphingolipid analogue GC with liposomal doxorubicin effectively overcame drug resistance. While toxicity and normal tissue exposure reduced, GC caused elevated levels of intracellular doxorubicin in the tumor, improved tumor growth inhibition and significantly prolonged survival. Thus, a strategy of GC-mediated doxorubicin translocation was the only therapeutic approach that generated a sustained doxorubicin anti-tumor response. Notably, enhanced doxorubicin translocation was strongest over membranes of the tumor, a spectacular observation confirmed in vitro. We demonstrate that composition and local organization of the plasma membrane determine the efficiency of membrane channel formation. In conclusion, transient membrane channels target the tumor cell membrane to overcome multi-drug resistance. Our results illuminate a critical role of the (tumor) plasma membrane in restricting the efficacy of anti-cancer drugs and its contribution to multi-drug resistance. Moreover, our findings present a mechanism to address these limitations of (candidate) drugs in a clinically applicable way. Citation Format: Albert J. van Hell, Manuel Melo, Wim van Blitterswijk, Tim Dijkema, Lilia Pedrosa, Gerben Koning, Siewert Jan Marrink, Jos Jonkers, Marcel Verheij. Formation of transient membrane channels targets doxorubicin resistance. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3382. doi:10.1158/1538-7445.AM2013-3382

Abstract 4515: Improvement of tissue distribution by the treatment of novel different double-arms polyethyleneglycol modified liposome encapsulating doxorubicin.

Abstract [Purpose] Polyethyleneglycol (PEG) modification on liposomal membrane increases therapeutic index by improvement of targeting based on prolonged blood stream circulation. In contrast, some accumulation of drug after liposome treatment has also been observed in normal tissues, it is necessary to improve liposomal composition on the decrease of adverse reactions. Particularly, doxorubicin (DOX) encapsulated liposome has some adverse reactions as cardiac toxicity or hand-foot syndrome,etc. To contribute superior liposome formulation, different double arms PEG in a molecule(DDA-PEG) was synthesized and was clarified effectiveness in our previous reports. In this study, we examined physical properties of novel synthesized DDA-PEG, and the tissue distribution of the DOX encapsulated liposome with modification of these DDA-PEGs. [Methods] Two DDA-PEGs with (PEG1000 and PEG500) or (PEG2000 and PEG500) were synthesized. Critical micelle concentration (cmc) in 10 mM Tris-HCl buffer (pH7.4) and 10 mM lactate buffer (pH4.0) was measured by the method of florescent probe using the 8-anilinonaphthalene-1-sulfonate (ANS). Octanol-buffer partitioning value was determined. DOX encapsulated liposomes with the modification of each DDA-PEGs were prepared by DSPC/cholesterol/DSPG-Na/DOX/PEG-lipid =100:100:60:18:7.5 μmol according to the method of Bangham. M5076 ovarian sarcoma cells were transplanted into the backs of BDF1 mice, and each liposome was injected intravenously at a dose of 2.5 mg DOX/kg on 15, 18 and 21 day after tumor inoculation. The mice were sacrificed after 2 day from last administration, and the tumor was removed and weighted. Moreover, DOX concentrations in each tissue were determined. [Results and discussion] The cmc of all PEG-lipids were same level. In PEG(2000, 500)-modified liposome, DOX concentrations in tumors were equal to that in PEG2000-modified liposome. On the other hand, DOX concentration in the heart after PEG(2000, 500) modified liposome and PEG(1000,500)-modified liposome treatments were one second and one sixth compared with DOX solution group, respectively. According to these results, it was expected that novel DDA-PEG-modified liposome was able to reduce the cardiac toxicity which is adverse reaction by DOX. The DOX concentration in the liver was showed a low level by PEG (1000, 500) modified liposome. It was suggested that novel DDA- PEG-modified liposome had the effect of avoiding the uptake into the liver. In conclusion, it was suggested that PEG(1000,500) modified liposome could decrease the DOX level in heart, and had ability of accumulation into tumor and avoidance from reticuloendothelial cells as same as PEG2000-modified liposome as known liposome. Citation Format: Mai Yagi, Ikumi Sugiyama, Yasuyuki Sadzuka. Improvement of tissue distribution by the treatment of novel different double-arms polyethyleneglycol modified liposome encapsulating doxorubicin. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4515. doi:10.1158/1538-7445.AM2013-4515

The differential accumulation of doxorubicin in the soleus and gastrocnemius muscle of the rat

The purpose of the present study was to examine intramuscular (IM) doxorubicin (DOX) levels in the soleus (S) and gastrocnemius (G) muscles of Sprague‐Dawley rats following the administration of DOX (1.5 or 4.5 mg/kg). Muscles were collected at 24, 48, 72 and 192 hrs post injection. DOX concentrations were elevated (P&lt;0.05) as compared to control at all time points. Following the 1.5 mg/kg dose, concentrations peaked in both muscles after 48 hrs, but were higher (P&lt;0.05) in the S (1.47±0.46 nmol/g) as compared to the G (0.78±0.24 nmol/g). Similarly, DOX was higher (P&lt;0.05) in the S (0.40±0.13 nmol/g) than the G (0.08±0.02 nmol/g) after 192 hours. The 4.5 mg/kg dose resulted in similar peak DOX concentrations in both the G (2.43±0.52 nmol/g) and the S (2.46±1.35 nmol/g), but this occurred sooner (48 hr) in the S as compared to the G (72 hrs). DOX levels were not different between muscle groups following 192 hrs. These data not only support the notion that DOX accumulates in skeletal muscle in a dose dependent manor, but clearly demonstrate that fiber type differences are a factor in the rate of accumulation and removal or degradation of intracellular DOX. These findings have clinical implications as skeletal muscle may be an important compartment for the sequestering of DOX from the circulation, effectively limiting its therapeutic impact. Supported by NSERC.

Abstract No. 330 - Comparison of serum doxorubicin levels following different DEB chemoembolization techniques as well as systemic administration in the same canine patients with naturally-occurring hepatocellular carcinoma

Purpose While the precise technique for DEB administration has not been completely elucidated, the most recent recommendations suggest delivering the beads as a drug delivery system and maintaining tumor perfusion rather than continuing to complete tumor stasis that may induce further angiogenesis. It is unclear how intratumoral and systemic doxorubicin levels are affected by DEB delivery performed with or without vascular stasis. Avoiding embolization may facilitate drug washout, reduce tumor doxorubicin concentrations, and increase systemic exposure to chemotherapy. We hypothesized that there would be a decrease in systemic doxorubicin exposure following DEB versus systemic chemotherapy and chemoembolization to stasis versus delivery without stasis. Materials and Methods Dogs diagnosed with naturally occurring nonresectable HCC were scheduled to receive three separate treatments ~5 weeks apart containing the same systemic dose of doxorubicin; 1) 100-300 DEB delivered without stasis, 2) 100-300 DEB delivery followed by Beadblock to stasis, and 3) intravenous doxorubicin. Serum doxorubicin levels were measured postoperatively. Results Serum doxorubicin levels were detectable for a median of 180, 30, and 1080 minutes following delivery without stasis (5 dogs), with stasis (7 dogs), and intravenously (4 dogs), respectively. Median maximum serum doxorubicin levels, median area-under-the-curve systemic doxorubicin levels, and median relative systemic doxorubicin exposures are reported in the Table . Conclusion Different DEB chemoembolization techniques may achieve different serum doxorubicin concentrations and therefore different intratumoral drug concentrations. When performing DEB chemoembolization in dogs with naturally occurring hepatocellular carcinoma, delivery to stasis results in the lowest systemic doxorubicin exposure (and presumably higher intratumoral concentrations) than when embolization to stasis in not performed.

Intramuscular doxorubicin accumulation and skeletal muscle fatigue: effects of prior exercise

The anthracycline antibiotic doxorubicin (DOX) has been shown to accumulate in skeletal muscle and result in muscle fatigue, but the role that exercise plays in DOX accumulation and fatigue in skeletal muscle is unclear. The purpose of this study was to examine the effects of exercise prior to DOX administration on intramuscular DOX accumulation and skeletal muscle fatigue. Ten‐week old, male Sprague‐Dawley rats were randomly assigned to an endurance training group (treadmill training), a resistance training group (raised food/water), or a sedentary group for 10 weeks. After the activity treatment period, animals received DOX or saline as a control. One day after injection, the soleus and extensor digitorum longus (EDL) were excised, and fatigue was analyzed ex vivo. DOX levels in the soleus and EDL were then quantified using high performance liquid chromatography. The endurance and resistance training models employed attenuated the increased muscle fatigue associated with DOX treatment, but this reduction in fatigue was not associated with decreased intramuscular DOX levels. This suggests that the beneficial effects of exercise on DOX‐induced skeletal muscle fatigue observed one day following treatment are not necessarily attributed to reduced intramuscular DOX levels.

Sildenafil is not a useful modulator of ABCB1 and ABCG2 mediated drug resistance in vivo

AimRecently, sildenafil was reported to be an inhibitor of P-glycoprotein (P-gp/ABCB1) and breast cancer resistance protein (BCRP/ABCG2) in vitro. We have now investigated the in vivo potency of sildenafil. MethodsBy using wild-type and Abcb1;Abcg2 knockout mice we have investigated the effect of sildenafil on the brain penetration of two substrate drugs (docetaxel and topotecan). Next we have investigated if sildenafil was able to improve the efficacy of doxorubicin against P-glycoprotein expressing CT26 colon cancer cells in syngeneic Balb/c mice. ResultsSildenafil administered orally at a dose of 50mg/kg did not improve the brain penetration of docetaxel and topotecan, although the plasma level of sildenafil was already much higher than can be achieved in humans. On the other hand, sildenafil increased the plasma levels of the cytotoxic drugs, but not by inhibition of Abcb1 or Abcg2, since this effect was also seen in Abcb1;Abcg2 knockout mice. The brain penetration of sildenafil was more than 20-fold higher in Abcb1;Abcg2 mice versus wild-type mice, indicating that sildenafil is a good substrate of the two transporters. Sildenafil was also not able to improve the efficacy of doxorubicin against subcutaneous CT26 tumours. The doxorubicin level in tumour tissue did increase, but so did the concentration of doxorubicin in plasma and heart. ConclusionThese results demonstrate that the potency and specificity of sildenafil as an inhibitor of ABCB1 and ABCG2 is not sufficient to warrant further clinical testing of this agent in combination with anticancer drugs.

Pegylated siRNA-loaded calcium phosphate nanoparticle-driven amplification of cancer cell internalization in vivo

The cell membrane is a critical barrier to effective delivery for many therapeutics, including those which are nanoparticle-based. Improving nanoparticle transport across the cell membrane remains a fundamental challenge. Cancer cells preferentially internalized pegylated calcium phosphate nanoparticles over normal epithelial cells. Furthermore, non-cytotoxic levels of doxorubicin markedly amplified this difference by increasing free unbound caveolin-1 and resulted in enhanced caveolin-mediated nanoparticle endocytosis in cancer cells. Engineered pegylated siRNA-loaded triple-shell calcium phosphate nanoconstructs incorporating ultra-low levels of doxorubicin recapitulated these effects and delivered increased numbers of siRNA into cancer cells with target-specific results. Systemic administration of nanoparticles in vivo demonstrated highly preferential entry into tumors, little bystander organ biodistribution, and significant tumor growth arrest. In conclusion, siRNA-loaded calcium phosphate nanoparticles incorporating non-cytotoxic amounts of doxorubicin markedly enhances nanoparticle internalization and results in increased payload delivery with concomitant on-target effects.

Chemoembolization and Radioembolization for Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) continues to represent a major worldwide problem. Although treatments such as resection, transplantation, and ablation may provide a chance for a cure, these options are often precluded because of advanced disease presentation. Palliative treatments include transarterial embolization and systemic therapies. This review will summarize the state of the science for embolic therapies in HCC (conventional and drug-eluting chemoembolization, radioembolization) as well as discuss related topics including HCC staging, assessment of response, and ongoing clinical trials.

Chemosensetizing and cardioprotective effects of resveratrol in doxorubicin- treated animals.

BackgroundDoxorubicin (DOX), an anthracycline antibiotic is one of the most effective anticancer drug used in the treatment of variety of cancers .Its use is limited by its cardiotoxicity. The present study was designed to assess the role of a natural product resveratrol (RSVL) on sensitization of mammary carcinoma (Ehrlich ascites carcinoma) to the action of DOX and at the same time its protective effect against DOX-induced cardiotoxicity in rats.MethodsEhrlich ascites carcinoma bearing mice were used in this study. Percent survival of tumor bearing mice was used for determination of the Cytotoxic activity of DOX in presence and absence of RSVL. Uptake and cell cycle effect of DOX in tumor cells in the presence of RSVL was also determined. Histopatholgical examination of heart tissues after DOX and/or RSVL therapy was also investigated.ResultsDOX at a dose level of 15 mg/kg increased the mean survival time of tumor bearing mice to 21 days compared with 15 days for non tumor-bearing control mice. Administration of RSVL at a dose level of 10 mg/kg simultaneously with DOX increased the mean survival time to 30 days with 70% survival of the tumor-bearing animals. RSVL increased the intracellular level of DOX and there was a strong correlation between the high cellular level of DOX and its cytotoxic activity. Moreover, RSVL treatment showed 4.8 fold inhibition in proliferation index of cells treated with DOX. Histopathological analysis of rat heart tissue after a single dose of DOX (20 mg/kg) showed myocytolysis with congestion of blood vessels, cytoplasmic vacuolization and fragmentation. Concomitant treatment with RSVL, fragmentation of the muscle fiber revealed normal muscle fiber.ConclusionThis study suggests that RSVL could increase the cytotoxic activity of DOX and at the same time protect against its cardiotoxicity.