Redirecting adenovirus to pulmonary endothelium by cationic liposomes

Somatic gene transfer to the pulmonary endothelium may be a useful strategy for modifying the phenotype of endothelium and/or vascular smooth muscle in disorders such as primary pulmonary hypertension, ARDS or pulmonary metastatic disease. Adenoviral (Ad) vectors, although highly efficient in liver gene transfer, have proven to be limited for pulmonary gene transfer with respect to efficiency, in part because of difficulty in assuring significant residence time in the lung and/or paucity of receptors for adenovirus on the endothelium. A recent study has shown that the use of a bispecific antibody to endothelial cells and Ad vectors efficiently redirects Ad vectors to pulmonary endothelium and improves gene expression in the lung. In this study, we report that pulmonary gene transfer by Ad vectors can also be improved significantly via the use of cationic liposomes. Preinjection of cationic liposomes followed by adenovirus led to a significant increase in the level of gene expression in the lung. The improvement in pulmonary gene transfer was associated with a decrease in the level of gene expression in the liver. Gene expression in the lung lasted for up to 2 weeks. This protocol, together with genetic modification of adenovirus, may prove to be useful for pulmonary gene transfer for the treatment of pulmonary diseases. This method may also be extended to pulmonary gene transfer using other types of viral vectors via vascular route.     

Induction of apoptosis in A549 human lung cancer cells by all-trans retinoic acid incorporated in DOTAP/cholesterol liposomes

All-trans retinoic acid (ATRA) has been shown to exert anti-cancer activities in a number of types of cancer cells. However, it has been reported that many NSCLC exhibited resistance to ATRA treatment. In the present study, we hypothesized that intracellular delivery of ATRA would overcome the ATRA resistance in A549 cells. Here, we investigated the induction of apoptosis by ATRA incorporated in cationic liposomes composed of DOTAP/cholesterol in A549 human lung cancer cells, which are insensitive (resistant) to the growth inhibitory effects of ATRA. The zeta potentials of DOTAP/cholesterol liposomes and DSPC/cholesterol liposomes were about + 50 and − 3 mV. In A549 cells, [³H]ATRA incorporated in DOTAP liposomes showed increased cellular association compared with [³H]ATRA or [³H]ATRA incorporated in DSPC/cholesterol liposomes. ATRA incorporated in DOTAP/cholesterol liposomes showed much higher cytotoxic effects and apoptosis-inducing activity compared with ATRA or ATRA incorporated in DSPC/cholesterol liposomes. The enhanced expression of TIG3 mRNA tumor suppressor gene by ATRA incorporation into DOTAP/cholesterol liposomes might partly explain the mechanism of enhanced cytotoxicity and/or apoptosis. These observations provide valuable information to help in the design of differentiation therapy by ATRA in non-small cell lung carcinoma.     

CNS relapses of acute promyelocytic leukemia after all-trans retinoic acid

OBJECTIVE: To review the role of all-trans retinoic acid (ATRA) and arsenic trioxide in central nervous system (CNS) relapses of acute promyelocytic leukemia (APL). CASE SUMMARY: A 69-year-old white man diagnosed with APL presented with bleeding diathesis. His molecular and cytogenetic studies were positive for promyelocytic leukemia-retinoic acid receptoralpha (PML-RARalpha) and t(15;17) transformation. Complete molecular and cytogenetic remission was achieved with ATRA, daunorubicin, and cytarabine. Within 6 months, the patient was readmitted for investigation of severe global headaches and an ataxic gait. His peripheral blood and cerebral spinal fluid were positive for PML-RARalpha fusion protein. Intrathecal chemotherapy and radiation, as well as ATRA, were the main treatment modalities provided. Molecular and cytogenetic remission was again obtained. Three months later, a second relapse occurred in the CNS and the peripheral blood. DISCUSSION: APL is typically treated with anthacycline-based chemotherapy and ATRA. Approximately 85-95% of patients achieve complete remission (CR); however, the relapse rate has been reported to be about 30-40%. A thorough literature search (MEDLINE, EMBASE, CANCERLIT, 1966-January 2002) revealed only 54 cases of extramedullary disease, of which 35 involved the CNS. CONCLUSIONS: The introduction of ATRA has improved patient survival dramatically. APL relapse, in general, has been in part attributable to repetitive or prolonged exposure to ATRA and the possibility of additional chromosomal changes, making the disease more refractory to treat. Given the evidence, one could argue that, with repeated ATRA treatment, CR duration may be shortened. However, limited data are available to guide the appropriate management of APL relapsed to the CNS with either ATRA, chemotherapy, or arsenic trioxide. In our opinion, treatment using arsenic trioxide is an unconventional option worthy of exploring.     

Restoration of oral all-trans retinoic acid bioavailability after a brief drug holiday.

We evaluated the utility of a 7-day drug holiday in the restoration of chronic dosing all-trans-retinoic acid (tRA) blood levels in 11 non-small cell lung carcinoma patients. Baseline kinetic studies (day 1) were compared to postchronic dosing (day 7) and drug holiday kinetics (day 14). High levels of baseline pharmacokinetic variability and variability in response to prolonged tRA therapy were evident. Median area under the curve (AUC) decreased from a baseline level of 1.2 to 0.69 microg/ml/h (p = 0.03). t (1/2) showed no significant alterations. A near-significant increase in T (lag) (p = 0.08) was noted, which suggests modulation of absorbance parameters. Trends in AUC were strongly correlated with C (max) as was T (max) with T (lag). After a 7-day drug holiday the median AUC significantly increased from the day 7 value to 1.8 microg/ml/h p = 0.01). Since post-drug holiday values for parameters were not statistically different from baseline pharmacokinetic values, this suggests a complete restoration of tRA bioavailability.     

Chemoprevention of 4-NQO-induced oral carcinogenesis by co-administration of all-trans retinoic acid loaded microspheres and celecoxib.

All-trans retinoic acid (atRA) is one of the most potential chemopreventive agents for head and neck squamous cell carcinoma (HNSCC). However, the induced metabolism of atRA by cytochrome P450s in the liver limits its clinical applications. To overcome such limitation, we had developed atRA-loaded microspheres designed to release atRA for a long period. Unfortunately, the atRA-loaded microspheres severely induced inflammatory responses: that is, atRA released from the microspheres significantly induced the proliferation of fibroblasts and collagen deposition, thereby causing a permeability barrier for drugs from entering the blood stream. In the present study, the effects of celecoxib as an anti-inflammatory drug are investigated when it is concurrently used with atRA-loaded microspheres to treat 4-NQO-induced oral carcinogenesis. We investigated if it might influence the plasma concentration of atRA and its metabolism by preventing the fibroblast proliferation and collagen deposition, reduce the toxicity level of atRA, and improve the chemopreventive efficacy of atRA-loaded microspheres. The concurrently administered celecoxib prevented inflammatory responses and suppressed the number of fibroblasts and collagen deposition in the fibrous capsules for 14 days. The atRA concentration in plasma was also increased and the metabolism of atRA was significantly decreased within 2 weeks. In the 4-NQO-induced oral carcinogenesis study, the incidence of invasive SCC was above 44% when F344 rats were treated with atRA-loaded microspheres. However, the treatment using atRA-loaded microspheres and celecoxib concurrently could reduce the incidence of invasive SCC up to 28%, and three of 25 rats were found to have no tongue lesions. In conclusion, the concurrent use of celecoxib could maintain the atRA concentration in plasma at a higher level while reducing its metabolism by preventing inflammatory responses, thereby improving their chemopreventive effects against 4-NQO-induced oral carcinogenesis.     

冈田酸对全反式维甲酸诱导NB4、MR2细胞分化的影响

目的 探讨丝(苏)氨酸蛋白磷酸化酶2A(PP2A)抑制剂冈田酸(Okadaic acid,OKA)对全反式维甲酸(ATRA)诱导白血病细胞分化的影响,探讨PP2A活性与白血病细胞ATRA耐药的关系.方法 用ATRA、OKA、ATRA+OKA分别作用于急性早幼粒细胞白血病细胞系NB4细胞及其耐药细胞系MR2细胞,采用瑞特染色法和NBT还原实验观察细胞形态变化,流式细胞术分析细胞表面CD11b表达,丝(苏)氨酸蛋白磷酸化酶试剂盒检测细胞内PP2A活性,Western blot法检测细胞内PP2A各亚基表达.结果 ①细胞形态学、NBT还原实验及流式细胞术检测结果均显示,加入OKA抑制蛋白磷酸化酶活性能促进ATRA诱导的NB4细胞分化,并协同ATRA能诱导其耐药细胞MR2细胞发生部分分化.②酶活性分析显示,未处理的NB4细胞PPA活性为(959±83)pmol磷酸盐·min-1,μg蛋白-1;ATRA诱导NB4细胞分化过程中,PP2A活性明显下降[(534±43)pmol磷酸盐·min-1.μg蛋白-1],ATRA+OKA组PP2A活性下降更加明显[(229±23)pmol磷酸盐·min-1·μg蛋白-1];单用ATRA作用于MR2细胞,则PP2A活性无明显影响,而ATRA+OKA诱导MR2细胞分化中,PP2A活性下降.③Western blot.结果 显示,ATRA作用5d的NB4细胞中PP2A-C亚基表达较对照组明显减少,而A和B亚基表达与对照组比较变化不明显;在MR2细胞中,A、B和C亚基表达在处理组与对照组之间无明显差别.结论 ATRA诱导的NB4细胞分化过程中细胞内PP2A-C表达减少,PP2A活性降低.ATRA不能有效抑制MR2细胞内PP2A的活性,可能是MR2细胞对ATRA耐药的机制之一.     

Induction of cancer cell-specific apoptosis by folate-labeled cationic liposomes.

We have previously reported that cationic liposomes themselves can induce apoptosis in macrophages and lymphocytes. In this paper, we attempted the cancer cell-specific delivery of cationic liposomes and the induction of apoptosis utilizing this characteristic. Cationic liposomes composed of stearylamine (SA-liposomes) induced apoptosis in human nasopharyngeal epidermoid carcinoma cells (KB cells) overexpressing the folate receptor and human fibroblasts (WI-38 cells) with no folate receptor, without showing selectivity. To recruit liposomes to cancer cells and induce apoptosis, we focused on the folate receptor and prepared folic acid-labeled liposomes using polyethyleneglycol (PEG) (folate-PEG-liposomes). Folate-PEG-liposomes showed selectivity and induced apoptosis in KB cells, but not WI-38 cells. The apoptosis occurred in a dose-dependent manner. Furthermore, folate-PEG-liposomes appear to associate with KB cells via the folate receptor, whereas SA-liposomes may associate with cells through electrostatic interactions. To confirm the contribution of the folate receptor to apoptosis of KB cells induced by folate-PEG-liposomes, the effect of folic acid on the apoptosis was examined. The addition of free folic acid drastically suppressed the apoptosis of KB cells and the percentage of cells with hypodiploid nuclei returned to the control level. Taken together, cationic liposomes labeled with folate bound to KB cells via folate receptors and, interestingly, the cationic liposomes themselves could cause apoptosis in cancer cells.     

全反式维甲酸对人白血病细胞系U937细胞生长的影响及其机制分析

目的 研究全反式维甲酸(ATRA)作用于人白血病细胞系U937细胞后,对细胞生长的影响及可能的机制.方法 收集1 μmol/L ATRA作用后的U937细胞,利用流式细胞术检测细胞周期分布,Western blot法检测细胞周期相关蛋白(cyclinA、p16、021、027及p27相关分子skp2)表达水平的变化,采用免疫沉淀方法检测U937细胞中027与Skp2的结合情况.结果 流式细胞术分析显示,在1μmol/L ATRA作用72 h后,72%的U937细胞被阻滞在G0/G1期.Western blot分析显示,ATRA能诱导cyclinA、Skp2表达下凋,p21、p27表达上调.免疫沉淀法检测结果显示在U937细胞中p27与skp2存在相互结合的情况.结论 ATRA可能主要通过诱导p27表达上调引起U937细胞生长阻滞,其过程是由p27相关分子Skp2所介导的.     

全反式维甲酸促进造血干/祖细胞植入的实验研究

目的　通过小鼠脐血移植 (UCBT)模型在体内观察全反式维甲酸 (RA)对脐血造血干 祖细胞 (HSPC)植入的影响。方法　用 380mg kg致死量环磷酰胺 (CTX)预处理后 ,将C57BL 6(H 2 b)的胎鼠和新生鼠外周血 (FNPB) (有核细胞数为 1× 1 0 6和 0 .5× 1 0 6个 )分别输注至BALB c(H 2 d)小鼠体内 ,于移植前 2天至移植后 2天分别用 1 5mg·kg-1 ·d-1 和 5mg·kg-1 ·d-1 RA处理受鼠 ,观察受鼠造血和免疫恢复、移植物抗宿主病 (GVHD)、植入水平和存活率。结果　经两种剂量RA处理后 ,造血和免疫重建明显加快 (P <0 .0 5)。未见急性GVHD。受鼠植入水平比对照组明显提高。当移植 1× 1 0 6细胞数时 ,两种剂量RA处理组均可提高移植后 30天和 60天存活率 (分别为 72 .73 %和 70 .83 % ) ,与对照组(41 .67% )相比 ,差异有显著性 (P <0 .0 5) ;当移植 0 .5× 1 0 6细胞数时 ,两种剂量RA亦能提高存活率(分别为 42 86 %和 43 .48% ) ,与未经RA处理对照组 (1 4 .2 9% )相比 ,差异有显著性 (P <0 .0 5) ,并且与移植 1× 1 0 6细胞数未经RA处理组的存活率相当。结论　在小鼠UCBT模型中 ,RA能促进脐血HSPC的植入 ,为RA应用于临床UCBT提供了实验依据     

全反式维甲酸和三氧化二砷诱导急性早幼粒细胞白血病细胞分化前后微小RNA表达变化

目的 研究急性早幼粒细胞白血病(APL)细胞分化前后微小RNA(miRNA,miR)表达变化.方法 采用全反式维甲酸(ATRA)和三氧化二砷(As2O3)诱导APL细胞系NB4 细胞分化,瑞氏-姬姆萨染色观察细胞形态,流式细胞术检测细胞表面标志CD11b的表达,用实时定量RT-PCR检测miRNA表达谱miR-15b、miR-16、miR-34a、miR-107、miR-124a、miR-146、miR-155、miR-181a、miR-223、miR-342、let7c等miRNA的表达水平,用2-△△Ct法计算miRNA相对表达水平.收集15例APL初诊和15例APL缓解期患者骨髓单个核细胞(MNC),用RT-PCR检测MNC miRNA 的表达水平,用2-△Ct法计算miRNA表达水平.结果 ATRA作用NB4细胞96 h,miR-15b、miR-16、miR-107、miR-223、miR-342表达水平均显著上调,分别为对照组的3.40、4.22、5.41、20.03和5.29倍,As2O3作用NB4细胞96 h,miR-15b、miR-16、miR-107、miR-223、miR-342表达水平也显著上调,分别为对照组的3.62、2.49、2.58、4.27和1.94倍,除miR-15b外,ATRA处理组miR-16、miR-107、miR-223和miR-342表达水平上调程度均高于As2O3处理组,其中尤以miR-223为甚.ATRA和As2O3治疗后缓解期APL患者miR-15b、miR-16、miR-107、miR-181a、miR-223和miR-342表达水平(2-△Ct值)分别为0.4137、0.6367、0.1260、0.0522、0.6611和0.0280,而APL初诊患者miR-15b、miR-16、miR-107、miR-181a、miR-223、miR-342表达水平分别为0.0751、0.2022、0.0425、0.3064、0.1733和0.0090,APL缓解期miR-15b、miR-16、miR-107、miR-223和miR-342表达水平高于APL初诊者(P值均<0.05),而APL缓解期miR-181a表达水平低于APL初诊者(P<0.05).结论 特定miRNA参与APL细胞分化过程.     

白血病细胞系纤溶活性及全反式维甲酸对其影响

目的研究不同白血病细胞系的纤溶活性，观察在全反式维甲酸（ATRA）作用下白血病细胞纤溶活性的变化及对尿激酶型纤溶酶原激活剂受体（uPAR）和膜联蛋白Ⅱ（AnnexinⅡ）表达的影响。方法用发色底物法测定白血病细胞系NB4、SHI-1、K562、Jurkat、Raji细胞的纤溶活性。用流式细胞术检测上述细胞表面uPAR和AnnexinⅡ的表达，以RT—PCR方法检测uPARmRNA和AnnexinⅡ mRNA的表达。结果NB4细胞和SHI-1细胞与纤溶酶原作用后上清液纤溶酶活性明显升高，ATRA处理后的NB4细胞纤溶活性明显下降。uPAR单抗可使SHI-1细胞和NB4细胞的纤溶活性明显下降。SHI-1细胞与NB4细胞表面的uPAR和AnnexinⅡ及其相应的mRNA表达较高，ATRA能下调NB4细胞AnnexinⅡ和uPAR及其相应的mRNA表达。结论不同白血病细胞使纤溶酶原转化为纤溶酶的能力不同，其中SHI-1细胞和NB4细胞促纤溶活性较强。白血病细胞表面AnnexinⅡ和uPAR共同参与了促纤溶作用。ATRA主要通过下调NB4细胞的AnnexinⅡ和uPAR蛋白及其mRNA的表达，纠正早幼粒细胞白血病的高纤溶状态。     

小剂量亚硒酸钠和全反式维甲酸联合使用诱导NB4细胞的凋亡及分化

目的 研究小剂量亚硒酸钠（2－5μmol/L）与全反式维甲酸（ATRA）联合使用对人急性早幼粒细胞白血病细胞株NB4凋亡及分化的影响。方法 采用膜联蛋白V（Annexin-V)荧光标记试剂盒检测细胞的磷脂酰丝氨酸（PS）外翻率和DNA片段化的琼脂糖凝胶电泳检测细胞凋亡，通过流式细胞术检测粒系分化细胞表面特异抗原CD11b表达，NBT还原实验检测细胞分化。结果 阴性对照组细胞术检测粒系分化细胞表达特异抗原CD11b表达，NBT还原实验检测细胞分化。结果 阴性对照组细胞PS外翻率为1．2％，5μmol/L亚硒酸钠处理NB4细胞48h后PS外翻率为0.8%,0.1μmol/L ATRA诱导48h后PS外翻率为2．0％，与对照组相比，差异均无显著性,而两者联合作用NB4细胞24，36，48h后的PS外翻率分别达到18.3%,25.9%,50.0%,DNA电泳呈典型的梯形带。小剂量（2μmol/L）亚硒酸钠没有诱导NB4细胞分化的能力，但其与0．1μmol/L的ATRA联合使用同单独使用0．1μmol/L的ATRA钠没有诱导NB4细胞分化的能力，但其与0．1μmol/L的ATRA联合使用单独使用0．1μmol/L的ARTA相比，CD11b表达阳性细胞率进一步增加，NBT还原能力也进一步增强。结论 小剂量的亚硒酸钠与ATRA联合使用可诱导NB4细胞发生凋亡及分化。     

维甲酸和三氧化二砷下调NB4细胞组织因子表达的作用机制

目的 研究全反式维甲酸（ＡＴＲＡ）和三氧化二砷（Ａｓ２Ｏ３）下调ＮＢ４细胞组织因子（ＴＦ）表达的作用机制。方法 用放线菌酮抑制蛋白合成和用放线菌素Ｄ阻断ＲＮＡ合成后,用逆转录－降合酶链反应（ＲＴ－ＰＣＲ）检测ＡＴＲＡ对ＮＢ４细胞ＴＦｍＲＮＡ转录的影响。将含有ＰＭＬ－ＲＡＲα融合蛋白全部编码序列的重组逆转录病毒质粒转染Ｕ９３７细胞,以转染空载体的Ｕ９３７细胞为对照,用ＥＬＩＳＡ方法检测ＡＴＲＡ和Ａｓ     

硼替佐米对全反式维甲酸和蟾蜍灵诱导的HL-60细胞分化过程中黏附功能的影响及其机制研究

目的 观察在低剂量蟾蜍灵联合全反式维甲酸(ATRA)诱导HL-60细胞向粒-单核细胞分化过程中细胞黏附功能的变化,检测黏附相关蛋白Pyk2及其底物蛋白Paxillin表达的变化,并探讨蛋白酶体通路对细胞黏附功能以及Pyk2和Paxillin表达的影响.方法 采用流式细胞术检测细胞CD11b的表达;采用MTT法检测细胞黏附能力;采用Western blot技术检测Pyk2、Paxillin和微管蛋白(Tubulin)的表达水平.结果 低剂量蟾蜍灵+ATRA联合用药以时间依赖性的方式诱导HL-60细胞分化,CD11b阳性率在处理2 d和4 d分别为(20.0±2.8)%和(75.0±5.3)%,并伴有细胞黏附功能苘的上调.同时Pyk2和Paxillin表达水平的上调也呈时间依赖性.蛋白酶体抑制剂硼替佐米以剂量依赖性的方式抑制细胞黏附能力,0、1和10 nmol/L硼替佐米处理的HL-60细胞的黏附水平分别为(9.4±0.8)%、(7.8±0.1)%和(5.3±0.3)%,硼替佐米处理组同时伴有Pyk2表达水平的下调,但Paxillin的表达不受影响.结论 Pyk2参与细胞黏附功能的调节;蛋白酶体通路抑制剂PS-341可能通过下调Pyk2表达,抑制HL-60细胞黏附功能.     

急性早幼粒细胞白血病全反式维甲酸治疗时IL—8及其受体表达 …

目的：探讨白细胞介素８（ＩＬ－８）及其Ａ型受体（ＩＬ－８ＲＡ）的表达在全反式维甲酸（ＡＴＲＡ）诱导治疗急性早幼粒细胞白血病（ＡＰＬ）中的临床意义。方法：动态检测ＡＰＬ患者１８例ＡＴＲＡ治疗中血浆ＩＬ－８水平（ＥＬＩＳＡ法）取３例骨髓单个核细胞（ＭＮＣ）加ＡＴＲＡ（１０＾－６ｍｍｏｌ／Ｌ）体外诱导，流式细胞仪动态检测ＭＮＣ膜Ｌ－８ＲＡ的表达。结果：ＭＮＣ加入ＡＴＲＡ诱导７２小时，上清ＩＬ－８水平明显     

活化素A和视黄酸诱导骨髓间充质干细胞体外分化为胰岛素分泌细胞

背景：胰岛移植是治疗Ⅰ型糖尿病的最有效的方法。然而，供体组织来源的匮乏限制了其应用。近来干细胞研究的进展表明，干细胞疗法可能解决这一问题。 目的：采用活化素A和视黄酸诱导骨髓间充质干细胞分化，探讨骨髓间充质干细胞分化为胰岛素分泌细胞的可能性。 设计：随机对照实验。单位：解放军军事医学科学院生物工程研究所。材料：实验于2004-11／2005-06在解放军军事医学科学院生物工程研究所完成。Sprague-Dawley大鼠6只，雄性，体质量150-160g，由解放军军事医学科学院实验动物中心提供。 方法：无菌抽取大鼠股骨骨髓，采用密度梯度离心法分离骨髓间充质干细胞。传代细胞随机分为4组，高糖组、活化素A和视黄酸组、β-巯基乙醇组和阴性对照组。分别采用含有高糖、活化素A和视黄酸、β-巯基乙醇等刺激因素的条件培养基进行诱导。应用免疫细胞化学和反转录聚合酶链反应等方法对分化细胞表型进行检测。 主要观察指标：检测胰岛素和胰高血糖素，以及胰岛素1mRNA的表达。 结果：骨髓间充质千细胞经过诱导后，①在高糖诱导组中，有散在的胰岛素和胰高血糖素阳性反应细胞出现。②活化素A和视黄酸组及β-巯基乙醇组有较多的胰岛素和胰高血糖素阳性反应细胞出现，而且这些细胞形成类似胰岛样的结构。③高糖组，活化素A和视黄酸组，β-巯基乙醇组均可见胰岛素lmRNA的表达。④阴性对照组未见有胰岛素和胰高血糖素阳性反应细胞出现以及胰岛素1mRNA的表达。 结论：实验建立的一种基于活化素A和视黄酸及其他成熟因子的一种诱导方案，成功将骨髓间充质干细胞诱导分化为胰岛素阳性反应细胞，并且形成类似胰岛样结构，但其诱导效率有待进一步提高。     

Controlled biodistribution of galactosylated liposomes and incorporated probucol in hepatocyte-selective drug targeting.

Two types of galactosylated liposomes containing cholesten-5-yloxy-N-(4-((1-imino-2-beta-D-thiogalactosyle thyl)amino)b utyl)formamide (Gal-C4-Chol) as a homing device were prepared to study the biodistribution of liposomal carriers and the incorporated drug. Distearoylphosphatidylcholine (DSPC)/cholesterol (Chol)/Gal-C4-Chol (60:35:5) (Gal DSPC), DSPC/Chol (60:40) (DSPC), egg yolk phosphatidylcholine (eggPC)/Chol/Gal-C4-Chol (60:35:5) (Gal eggPC), and eggPC/Chol (60:40) (eggPC) liposomes labeled with [(3)H]cholesteryl hexadecyl ether (CHE) were tested and [(14)C]probucol, with a partition coefficient between octanol and water (PC(oct)) of 10(10.8), was selected as a model drug with lipophilicity suitable for liposomal incorporation. After intravenous injection of the combination of [(14)C]probucol and [(3)H]liposomes, the liver uptake of [(3)H]CHE was the highest in Gal DSPC liposomes, followed by Gal egg PC liposomes, egg PC liposomes, and DSPC liposomes in that order. [(14)C]Probucol incorporated in Gal DSPC liposomes exhibited lower liver uptake than [(3)H]CHE, suggesting that substantial release from liposomes had taken place. In contrast, [(14)C]probucol incorporated in Gal eggPC liposomes was more stably incorporated under in vivo conditions. Co-administration with galactosylated bovine serum albumin significantly inhibited the liver uptake of [(14)C]probucol in both types of galactosylated liposomes, suggesting that the hepatic uptake of liposomes should be mediated by asialoglycoprotein receptors being [(14)C]probucol incorporated in them.