Enhanced Intracellular Uptake of Sterically Stabilized Liposomal Doxorubicin <Emphasis Type="Italic">in Vitro</Emphasis> Resulting in Improved Antitumor Activity <Emphasis Type="Italic">in Vivo</Emphasis>

Purpose To investigate the correlation between the in vitro intracellular uptake and the in vivo antitumor activity of anticancer drugs delivered by sterically stabilized liposomes (SSL).Methods Arginine-glycine-aspartic acid (RGD) peptide or RGD mimetic (RGDm) was coupled onto the surface of SSL to obtain the cell-binding carrier to facilitate the intracellular delivery of the encapsulated drugs. DOX-loaded SSL (SSL-DOX), DOX-loaded RGD-modified SSL (RGD-SSL-DOX) and DOX-loaded RGDm-modified SSL (RGDm-SSL-DOX) were prepared by lipid film dispersion followed by remote loading of DOX. The intracellular uptake of DOX from the various liposomal formulations was evaluated in vitro with melanoma B16 cells, and the pharmacokinetics, biodistribution, and antitumor activity were compared in C57BL/6 mice carrying melanoma B16 tumors.Results In vitro intracellular uptake of DOX by B16 cells and in vivo antitumor activity in terms of tumor growth inhibition and mice survival time prolongation for various liposomal DOX were in the following order: RGD-SSL-DOX > RGDm-SSL-DOX > SSL-DOX. The mean survival time of the mice treated with RGD-SSL-DOX, RGDm-SSL-DOX, and SSL-DOX was 55, 49, and 44 days, respectively. The three liposomal DOX formulations produced very close DOX accumulation in tumor, which is significantly higher than that of free DOX. RGD- or RGDm-SSL-DOX demonstrated prolonged circulation time similar to that of SSL-DOX, whereas they showed significantly lower DOX level in blood and remarkably higher uptake by spleen than SSL-DOX.Conclusions Enhanced intracellular uptake of DOX encapsulated in SSL could produce an improved therapeutic effect for the melanoma B16 tumors. Enhancing intracellular delivery of the anticancer drugs encapsulated in SSL may be a promising strategy to improve their therapeutic efficacy for solid tumors.     

Folate receptor-mediated liposomal delivery of a lipophilic boron agent to tumor cells in vitro for neutron capture therapy

Purpose. This study was aimed at the in vitro evaluations of folate receptor (FR)-targeted liposomes as carriers for a lipophilic boron agent, K[nido-7-CH₃(CH₂)₁₅-7,8-C₂B₉H₁₁], in FR-overexpressing tumor cells for neutron capture therapy. Methods. Large unilamellar vesicles (200 nm in diameter) were prepared with the composition of egg PC/chol/K[nido-7-CH₃(CH₂)₁₅-7,8-C₂B₉H₁₁] (2:2:1, mol/mol), with an additional 0.5 mol % of folate-PEG-DSPE or PEG-DSPE added for the FR-targeted or nontargeted liposomal formulations, respectively. Results. Boron-containing, FR-targeted liposomes readily bound to KB cells, an FR-overexpressing cell line, and were internalized via FR-mediated endocytosis. The boron uptake in cells treated with these liposomes was approximately 10 times greater compared with those treated with control liposomes. In contrast, FR-targeted and nontargeted liposomes showed no difference in boron delivery efficiency in F98 cells, which do not express the FR. The subcellular distribution of the boron compound in KB cells treated with the FR-targeted liposomes was investigated by cellular fractionation experiments, which showed that most of the boron compound was found in either the cytosol/endosomal or cell membrane fractions, indicating efficient internalization of the liposomal boron. Conclusion. FR-targeted liposomes incorporating the lipophilic boron agent, K[nido-7-CH₃(CH₂)₁₅-7,8-C₂B₉H₁₁], into its bilayer were capable of specific receptor binding and receptor-mediated endocytosis in cultured KB cells. Such liposomes warrant further investigations for use in neutron capture therapy.     

Trastuzumab and Liposomal Doxorubicin in the Treatment of MCF-7 Xenograft Tumor-Bearing Mice: Combination Does Not Affect Drug Serum Levels

Purpose We assessed the combination of doxorubicin or liposomal doxorubicin with trastuzumab for alterations in peak serum drug levels, as these agents are increasingly being paired in the treatment of aggressive breast cancer. We hypothesized that trastuzumab would exhibit a slower rate of elimination from the serum when in combination with liposomal doxorubicin based on the known effects of liposomal doxorubicin on phagocytic cells of the mononuclear phagocyte system (MPS), which are responsible in part for the uptake and degradation of antibodies.Methods Doxorubicin and trastuzumab serum levels were assessed following injection of free doxorubicin, liposomal doxorubicin, or trastuzumab into female RAG2-M mice bearing subcutaneous MCF-7^HER-2 tumors. The effects of combination drug treatment on tumor growth were compared to single-agent treatment.Results Peak serum trastuzumab levels were not altered as a result of addition of doxorubicin therapy, nor were doxorubicin levels altered over 24 h as a result of coadministration of trastuzumab. Liposomal doxorubicin administration did result in serum doxorubicin levels 200- to 1000-fold higher than with injection of free doxorubicin.Conclusions For the specific combination of trastuzumab with doxorubicin, either in free or liposomal form, coadministered in mice, there was no impact of one drug on the other in terms of peak serum drug levels or efficacy.     

多柔比星叶酸隐形脂质体对HeLa229荷瘤裸鼠的抑瘤作用

考察多柔比星（1）叶酸隐形脂质体对荷瘤裸鼠肿瘤生长的抑制作用。以pH梯度法分别制备了多柔比星叶酸隐形脂质体（1-FSL）和普通脂质体。比较两者在荷瘤裸鼠瘤旁给药后对瘤体动态变化趋势、瘤体组织病理学差异和瘤体中肿瘤细胞DNA质量的影响等。结果表明，1-FSL对荷瘤裸鼠具有显著的抑瘤效果，1-FSL抑瘤率略高于普通脂质体，但两者抑瘤特性明显有别。     

Formulation and Evaluation of a Folic Acid Receptor-Targeted Oral Vancomycin Liposomal Dosage Form

Purpose. To demonstrate utility of folic acid-coated liposomes for enhancing the delivery of a poorly absorbed glycopeptide, vancomycin, via the oral route. Methods. Liposomes prepared as dehydration-rehydration vesicles (DRVs) containing vancomycin were optimized for encapsulation efficiency and stability. A folic acid-poly(ethylene oxide)-cholesterol construct was synthesized for adsorption at DRV surfaces. Liposomes were characterized by differential scanning calorimetry (DSC) and assessed in vitroin the Caco-2 cell model and in vivoin male Sprague-Dawley rats. Non-compartmental pharmacokinetic analysis of vancomycin was conducted after intravenous and oral administration of solution or liposome-encapsulated vancomycin with or without 0.05 mole ratio FA-PEO-Chol adsorbed at liposome surfaces. Results. Optimal loading of vancomycin (32%) was achieved in DRVs of DSPC:Chol:DCP, 3:1:0.25 mole ratio (m.r.) after liposome extrusion. Liposomes released less than 40% of the entrapped drug after 2 hours incubation in simulated gastrointestinal (GI) fluid and simulated intestinal fluid containing a 10 mM bile salt cocktail. Incorporation of FA-PEO-Chol in liposomes increased drug leakage by 20% but resulted in a 5.7-fold increase in Caco-2 cell uptake of vancomycin. Liposomal delivery significantly increased the area under the curve of oral vancomycin resulting in a mean 3.9-fold and 12.5-fold increase in relative bioavailability for uncoated and FA-PEO-Chol-coated liposomes, respectively, compared with an oral solution. Conclusions. The design of FA-PEO-Chol-coated liposomes resulted in a dramatic increase in the oral delivery of a moderate-size glycopeptide in the rat compared with uncoated liposomes or oral solution. It is speculated that the cause of the observed effect was due to binding of liposome-surface folic acid to receptors in the GI tract with subsequent receptor-mediated endocytosis of entrapped vancomycin by enterocytes.     

Efficacy of Liposomal Monensin on the Enhancement of the Antitumour Activity of Liposomal Ricin in Human Epidermoid Carcinoma (KB) Cells

The monensin, known to enhance the cytotoxicity of ricin and ricin-based immunotoxins is a very hydrophobic molecule and this limits its administration in optimum doses under in vivo conditions. In order to realise its full potential, monensin was intercalated into various liposomal formulations and its ability to potentiate the cytotoxicity of ricin liposomes in human epidermoid carcinoma (KB) cells was studied. It was observed that ricin cytotoxicity enhancing ability of monensin liposome depends on the surface charge as well as density and chain length of distearoyl phosphatidylethanolamine-methoxy polyethylene glycol present on the surface of liposomal monensin. Maximum potentiation on the cytotoxicity of liposomal ricin was observed by monensin entrapped in neutral liposome (106.5 fold) followed by negatively charged (94.2 fold) and positively charged liposome (90 fold). Studies on the effect of variation of density and chain length of distearoyl phosphatidylethanolamine-methoxy polyethylene glycol showed that neutral monensin liposomes having 2.5 mol% distearoyl phosphatidylethanolamine-methoxy polyethylene glycol with chain length of 2000 exhibits maximum potentiation (117.6 fold) on the cytotoxicity of ricin liposomes when the cellular uptake of monensin liposome was maximum (42.0%) and the zeta potential value on the surface of liposomes was −0.645. The present study has clearly shown that liposomal monensin is very effective in enhancing the cytotoxicity of liposomal ricin in human cancer cells and liposome can be used as in vivo deliver vehicle for monensin to potentiate the cytotoxicity of liposomal ricin to eliminate cancer cells.     

Antitumor effect of folate-targeted liposomal doxorubicin in KB tumor-bearing mice after intravenous administration

The effect of folate-targeted liposomal doxorubicin (FTL-Dox) has been well characterized in folate receptor (FR) overexpressing tumors in vitro, particularly in KB human carcinoma cells. However, there are few studies evaluating the in vivo efficacy of FTL-Dox in KB murine xenograft models. In this study, we investigated the antitumor activity of FTL-Dox injected intravenously in mice bearing KB tumors. Folate ligands comprising of folate-polyethyleneglycol-distearoylphosphatidylethanolamine (FA-PEG-DSPE) were synthesized with different MW PEG. To design an optimum FTL-Dox formulation for therapeutic studies, we prepared various FTLs and characterized their in vitro targeting and in vivo tissue biodistribution. Mice were administered a single intravenous injection of free Dox, nontargeted PEGylated liposomal Dox (PL-Dox), or FTL-Dox. FTLs and PLs accumulated similarly in tumor tissue, despite FTLs’ faster clearance from circulation. Mice treated with FTL-Dox 20?mg/kg had a slightly greater tumor growth inhibition and almost a 50% increase in life span than mice receiving PL-Dox 20?mg/kg (P?=?0.0121; log-rank test). We conclude that FTLs administered systemically have the potential to enhance the delivery of anticancer drugs in vivo; however, their removal by FR expressing normal tissues may have to be blocked if the benefits of tumor targeting are to be realized.     

Biochanin A Inhibits Breast Cancer Tumor Growth in A Murine Xenograft Model

PURPOSE: Our objective was to determine the effect of the flavonoid biochanin A (BCA), administered alone or in combination with the flavonoids quercetin and epigallocatechin-3-gallate (EGCG), on the growth of human breast cancer MCF-7 cells in a murine xenograft animal model. MATERIALS AND METHODS: MCF-7 tumors were implanted into mice and groups of mice were treated with vehicle, BCA at 2 doses (5 or 15 mg/kg), quercetin and EGCG (5 mg/kg each), or BCA combined with quercetin and EGCG (5 mg/kg each). The flavonoids were injected once daily intraperitoneally, with treatment starting 4 weeks prior to cell inoculation. RESULTS: Treatment with 15 mg/kg of BCA or the mixture of the 3 flavonoids resulted in a reduction in tumor incidence. Tumor size in xenograft mice treated with 15 mg/kg BCA was significantly smaller than in the control group. Although quercetin/EGCG administration did not affect tumor size, treatment with the mixture of the 3 flavonoids at doses of 5 mg/kg produced similar effects as seen with 15 mg/kg BCA. CONCLUSIONS: Our findings indicate that BCA inhibits tumor growth in a xenograft animal model; BCA may represent a breast cancer preventive agent, either administered alone or in combination with other flavonoids.     

Lectin-Mediated Drug Targeting: Preparation,Binding Characteristics,and Antiproliferative Activity of Wheat Germ Agglutinin Conjugated Doxorubicin on Caco-2 Cells

Purpose. To investigate the usefulness of wheat germ agglutinin as a targeting carrier protein for an acid-labile chemotherapeutic prodrug directed against colon carcinoma cells in vitro. Methods. Cis-aconityl-linked doxorubicin-wheat germ agglutinin was prepared by a two step procedure and the conjugate-binding capacity of target- and non-target cells was assayed by flow cytometry. The antiproliferative activity of the prodrug on Caco-2 and MOLT-4 cells was determined by the XTT- and BrdU-test and compared with that of the parent drug and the lectin alone. Results. At pH 4.0, about 50% of the conjugated doxorubicin were released within 24 h from the water soluble prodrug exhibiting a conjugation number of 24 (mol doxorubicin/mol WGA). The prodrug-binding capacity of colon carcinoma cells exceeded that of human colonocytes and lymphoblastic MOLT-4 cells 4.5-fold. Additionally, the antiproliferative effect of the conjugate on Caco-2 cells was 39% as opposed to 5% in case of MOLT-4 cells. As the unmodified carrier protein inhibited or stimulated Caco-2 cell growth in a concentration-dependent manner, the cytostatic activity of the conjugate was determined at WGA concentrations without an effect on cell-proliferation. Considering 50% release of conjugated drug at the most, the prodrug yielded 160% of the cytostatic activity of free doxorubicin. Conclusions. WGA-prodrug targeting offers new perspectives for site-specific, cytoinvading drug delivery in colon cancer chemotherapy.     

Liposomal delivery of photosensitising agents

Photodynamic therapy is a clinically approved treatment for cancer and noncancer diseases. This modality utilises light-activatable chemicals (photosensitising agents) to capture photons and use light energy for the production of cytotoxic reactive molecular species. Most photosensitisers that are in use clinically or in preclinical development are hydrophobic and tend to aggregate in the aqueous environment, which limits their delivery and photosensitising efficiency. Liposomal delivery of photosensitisers will often overcome or decrease these problems. In addition, as with chemotherapeutic agents, liposomal formulations of photo-sensitising agents may help to achieve better selectivity for tumour tissue compared with normal tissue. Over the past years, liposomal photosensitisers have emerged as therapeutic agents in many experimental studies, and have obtained approval for clinical applications. Recent progress in liposomal technology further opens up the possibility of generating more selectively targeted photosensitisers encapsulated in liposomes. This review will cover progress in the use of liposomal photosensitisers, summarise current liposomal formulations, and project future directions for the liposomal delivery of photosensitising agents.     

Synthesis of a New pH-Sensitive Folate–Doxorubicin Conjugate and its Antitumor Activity In Vitro

Folate–aminocaproic acid–doxorubicin (FA–AMA–DOX) was synthesized and characterized by H NMR spectroscopy and mass spectrometry. Cytotoxicity and cellular uptake experiments were performed in KB and HepG2 cells, which express folic acid receptor, and the cell line A549, which does not express folic acid receptor. Cytotoxicity was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, and cellular uptake was monitored using fluorescence microscopy. The amount of DOX released from FA–AMA–DOX was much greater at pH 5.0 than that at pH 6.5 or 7.4. The cytotoxicity of FA–AMA–DOX toward KB and HepG2 cells was greater than that of DOX or AMA–DOX at the same concentrations, and cytotoxicity could be attenuated by FA in a dose-dependent manner. On the contrary, the cytotoxicity of FA–AMA–DOX and AMA–DOX toward A549 cells was lower than that of DOX at the same concentration, and cytotoxicity could not be reduced by FA. Compared with FA–AMA, FA–AMA–DOX increased the intracellular accumulation of DOX in KB cells. These results suggested that FA–AMA–DOX have suitable attributes for the active targeting of folate-receptor-positive tumor cells and for releasing the chemotherapeutic agent, DOX, in situ; it therefore has potential as a novel cancer therapeutic. © 2012 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 102:530–540, 2013     

Enhanced Delivery and Antitumor Activity of Doxorubicin Using Long-Circulating Thermosensitive Liposomes Containing Amphipathic Polyethylene Glycol in Combination with Local Hyperthermia

Enhanced delivery of doxorubicin (DXR) to a solid tumor subjected to local hyperthermia was achieved by using long-circulating, thermosensitive liposomes (TSL) composed of dipalmitoyl phosphatidylcholine (DPPC)/distearoyl phosphatidylcholine (DSPC) (9:1, m/m) and 3 mol% amphipathic polyethylene glycol (PEG) in colon 26-bearing mice. Inclusion of 3 mol% of distearoyl phosphatidylethanolamine derivatives of PEG (DSPE-PEG, amphipathic PEG) with a mean molecular weight of 1000 or 5000 in DPPC/DSPC liposomes resulted in decreased reticuloendothelial system (RES) uptake and a concomitant prolongation of circulation time, affording sustained increased blood levels of the liposomes. Concomitantly, DXR levels in blood were also kept high over a long period. The presence of amphipathic PEG did not interfere with the encapsulation of DXR by the pH gradient method (>90% trapping efficiency) or with the temperature-dependent drug release from the liposomes. The optimal size of these liposomes was 180 – 200 nm in mean diameter for thermosensitive drug release and prolonged circulation time. The DXR levels in the tumor after injection of long-circulating TSL (DXR-PEG1000TSL or DXR-PEG5000TSL, at a dose of 5 mg DXR/ kg) with local hyperthermia were much higher than after treatment with DXR-TSL lacking PEG or with free DXR, reaching 7.0 – 8.5 DXR µg/g tumor (approximately 2 times or 6 times higher than that of DXR-TSL or free DXR, respectively). Furthermore, the combination of DXR-PEGTSL and hyperthermia effectively retarded tumor growth and increased survival time. Our results indicate that the combination of drug-loaded, long-circulating, thermosensitive liposomes with local hyperthermia at the tumor site could be clinically useful for delivering a wide range of chemotherapeutic agents in the treatment of solid tumors.     

Transferrin Receptor Targeted Lipopolyplexes for Delivery of Antisense Oligonucleotide G3139 in a Murine K562 Xenograft Model

Purpose  Transferrin (Tf) conjugated lipopolyplexes (LPs) carrying G3139, an antisense oligonucleotide for Bcl-2, were synthesized and evaluated in Tf receptor positive K562 erythroleukemia cells and then in a murine K562 xenograft model. Materials and Methods  Particle size and Zeta potentials of transferrin conjugated lipopolyplexs containing G3139 (Tf-LP-G3139) were measured by Dynamic Light Scattering and ZetaPALS. In vitro and in vivo sample’s Bcl-2 downregulation was analyzed using Western blot and tumor tissue samples also exhibited by immunohistochemistry method. For athymic mice bearing with K562 xenograft tumors, tumor growth inhibition and survival rate were investigated. Nanoparticle distribution in 3-D cell cluster was observed by Laser scan confocal microscopy. IL-12 production in the plasma was measured by ELISA kit. Results   In vitro, Tf-LP-G3139 was more effective in inducing down regulation of Bcl-2 in K562 cells than non-targeted LP-G3139, free G3139 and mismatched control ODN-G4126 in the same formulation. In vivo Tf-LP-G3139 was less effective than free G3139 in Bcl-2 down regulation. 3-D cell cluster model diffusion results indeed indicated limited penetration of the LPs into the cell cluster. Finally, the therapeutic efficacies of Tf-LP-G3139 and free G3139 were determined in the K562 xenograft model. Tf-LP-G3139 showed slower plasma clearance, higher AUC, and greater accumulation in the tumor compared to free G3139. In addition, Tf-LP-G3139 was found to be more effective in tumor growth inhibition and prolonging mouse survival than free G3139. This was associated with increased spleen weight and IL-12 production in the plasma. Conclusion  The role of the immune system in the therapeutic response obtained with the Tf-LPs is necessary and in vitro 3-D cell cluster model can be a potential tool to evaluate the nanoparticle distribution.     

PEG化脂质体多柔比星在动物体内的药动学及组织分布

比较研究了PEG化脂质体多柔比星(阿霉素)受试制剂与进口同类参比制剂静注后,在动物体内的药动学及组织分布.采用HPLC法测定Beagle犬的血药浓度和荷瘤(Walker256)Wistar大鼠各组织药物浓度.结果显示,Beagle犬静注1 mg/kg受试制剂及参比制剂后,药动学参数分别为t1/2β23.0和23.5 h,表观分布容积0.060和0.062 L/kg,AUC0-∞500.29和531.57μg·ml-1h,多柔比星在犬体内的药代动力学过程均符合二室模型的特征.荷瘤(Walker256)Wistar大鼠静注5 mg/kg受试制剂及参比制剂后,脾中含量最高,其次为肿瘤、小肠、肝,皮肤中含量最低.统计学分析显示,两制剂在犬体内主要药动学参数及大鼠组织肝、心、脾、肾、小肠、皮肤和肿瘤内的分布,无显著性差异(P>0.05).     

Reduced UV-Induced Degradation of Doxorubicin Encapsulated in Polyethyleneglycol-Coated Liposomes

Purpose. The aim of this study was to investigate the stability of doxorubicin encapsulated in polyethyleneglycol-coated liposomes (Doxil) under UV-A light. Methods. High performance liquid chromatography and a fluorimetric method were used to quantify doxorubicin in bulk solution and doxorubicin in Doxil formulation. Results. The photodegradation of Doxil was significantly lower in comparison to the photodegradation of the free drug and showed no concentration dependency at the measured concentration range of 5–50 g/ml. During and after UV-A irradiation, there was no leakage of the drug from liposomes to the medium. After induced leakage of doxorubicin from the liposomes by the ionophore nigericin, the degradation kinetics of Doxil were identical to that of free doxorubicin. Conclusions. High intraliposomal doxorubicin concentration and intraliposomal acidic pH are the two critical factors that protect DXR in Doxil from UV-A degradation.     

HPLC荧光法检测转铁蛋白修饰的阿霉素脂质体在小鼠体内的含量

目的建立转铁蛋白修饰的阿霉素脂质体在小鼠体内组织浓度的测定方法。方法选择乙腈-5 mmol·L^-1乙酸铵水溶液（30：70）为流动相;色谱柱：DIKMA Diamonsil C18柱（4．6min×150mm,5μm）;流速1．0mL·min^-1;检测波长：激发波长为480nm,发射波长为550nm;柱温：30℃。结果本实验所用方法线性关系良好,且具有专一性强,准确性、灵敏度高的优点,符合生物样本分析的要求。结论可用本法快速、简便、准确地测定小鼠组织样品中转铁蛋白修饰的阿霉素脂质体的含量。     

Rapid Doxorubicin Efflux from the Nucleus of Drug-Resistant Cancer Cells Following Extracellular Drug Clearance

Purpose Following extracellular drug clearance, we analyzed the rate of doxorubicin efflux from the nucleus of three human leukemic cells (K562, Molt4 and CCRF-CEM) and related it to their differential sensitivity to this drug, after a short drug pulse. Results For many pulse-chase regimes, K562 cell viability was least affected by doxorubicin. In K562 cells, nuclear drug accumulation was greatest, but nuclear drug egress was also greatest. P-glycoprotein over-expression in a doxorubicin-resistant, K562/DOX sub-line did not facilitate doxorubicin efflux from the nucleus. In K562 cells, doxorubicin accumulated in multivesicular bodies (MVBs) through a pH-dependent mechanism. Inhibiting drug sequestration in MVBs did not affect nuclear efflux. The rates of doxorubicin efflux from the nuclei of live and digitonin-permeabilized K562 cells were similar. However, extracting cytoplasmic membranes with Triton X-100 significantly inhibited nuclear drug efflux following extracellular drug clearance. Conclusion Our results are consistent with drug efflux from the nucleus being primarily mediated by an ATP-independent, passive diffusion mechanism. The effect of membrane extraction suggests that nonspecific drug absorption to cytoplasmic membranes plays a role in facilitating nuclear efflux in K562 cells, perhaps by lowering the concentration of free doxorubicin from a perinuclear diffusion boundary layer.     

聚乙二醇多柔比星脂质体联合化疗治疗晚期恶性肿瘤临床观察

目的探讨以聚乙二醇多柔比星脂质体为主联合化疗治疗晚期恶性肿瘤的临床疗效和不良反应。方法收集2007年1月—2009年11月以聚乙二醇多柔比星脂质体为主的联合化疗治疗晚期恶性肿瘤患者的治疗信息、临床情况,并对患者进行跟踪随访至2010年4月30日。结果 33例恶性肿瘤患者共计完成化疗106周期,中位3周期（1~8周期）,可评价疗效28例,其中完全缓解4例,占14.3%;部分缓解11例,占39.3%;稳定11例,占39.3%;进展2例,占7.1%;客观有效率为53.6%,临床受益率为92.9%。随访周期6~39个月,中位随访时间16个月,总生存时间4~39个月,中位生存时间16个月,无疾病进展时间2~39个月,中位无疾病进展时间为10个月,1和2年生存率分别为69.2%和34.2%,3例生存3年以上。不良反应主要为骨髓抑制、脱发和胃肠道反应,另外乏力、手足综合症常见,心脏毒性轻微。结论以聚乙二醇多柔比星脂质体为主联合化疗治疗晚期恶性肿瘤是有效的,患者可以良好耐受。     

Liposome-Mediated Therapy of Intracranial Brain Tumors in a Rat Model

Purpose. Malignant brain tumors represent a serious therapeutic challenge, and survival often is low. We investigated the delivery of doxorubicin (DXR) to rat brain tumors in situ vialiposomes, to test the hypothesis that intact liposomes undergo deposition in intracranial tumor through a compromised blood-tumor vasculature. Both therapeutic effect and intra-tumor drug carrier distribution were evaluated to identify variables in carrier-mediated delivery having impact on therapy. Methods. The rat 9L gliosarcoma tumor was implanted orthotopically in Fischer 344 rats in the caudate-putamen region. The tumor-bearing rats were treated with DXR, either free or encapsulated in long-circulating, sterically-stabilized liposomes. Anti-tumor efficacy was assessed by survival time. In parallel, liposomes labeled with a fluorescent phospholipid analog were injected into tumor-bearing rats. At predetermined intervals, the brains were perfused with fixative, sectioned, and imaged with laser scanning confocal microscope (LSCM) to investigate the integrity of the tumor vascular bed and the intratumor deposition of liposomes. Results. Free DXR given in 3 weekly iv injections was ineffective in increasing the life span of tumor-bearing rats at cumulative doses 17 mg/kg, and at the highest dose (17 mg/kg) decreased survival slightly, compared to saline-treated controls. In contrast, DXR encapsulated in long-circulating liposomes mediated significant increases in life span at 17 mg/kg. Rats showed a 29% percent increase in median survival, respectively, compared to saline-control animals. The delay of treatment after tumor implantation was a major determinant of therapeutic effect. Fluorescent liposomes were deposited preferentially in tumor rather than normal brain, and were distributed non-uniformly, in close proximity to tumor blood vessels. Conclusions. Liposomes can be used to enhance delivery of drugs to brain tumors and increase therapeutic effect. The therapeutic effect may arise from release of drug from liposomes extravasated in discrete regions of the tumor vasculature and the extravascular space.