Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C1658953 (tumor vasculature)
 2,390 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cationic liposomes have been shown to be internalized selectively by angiogenic tumor endothelial cells after intravenous injection. Therefore, encapsulation of cytotoxic substances in cationic liposomes is a new approach to target tumor vasculature. It was the aim of our study to quantify the effects of paclitaxel encapsulated in cationic liposomes (MBT-0206) on tumor microvasculature and growth in vivo. Experiments were performed in the dorsal skinfold chamber preparation of Syrian Golden hamsters bearing syngeneic A-Mel-3 melanomas. Tumors were treated with intravenous infusion of MBT-0206 (20 mM) resulting in an effective paclitaxel dose of 5 mg/kg body weight (b.w.). Control animals received conventional paclitaxel in Cremophor EL (Taxol(R); 5 mg/kg b.w.), unloaded cationic liposomes (20 mM) or the solvent 5% glucose, respectively. Using intravital microscopy, tumor growth and effects on intratumoral microvasculature were analyzed. Tumor growth was significantly retarded after treatment with MBT-0206 compared to the treatment with paclitaxel. Analysis of intratumoral microcirculation revealed a reduced functional vessel density in tumors after application of liposomal paclitaxel. At the end of the observation time, vessel diameters were significantly smaller in animals treated with paclitaxel encapsulated in cationic liposomes while red blood cell velocity was less affected. This resulted in a significantly reduced blood flow in vessel segments and a reduced microcirculatory perfusion index in these animals. Histochemical TUNEL stain was vessel-associated after treatment with liposomal paclitaxel in contrast to few apoptotic tumor cells in the control groups. Our data demonstrate that encapsulation of paclitaxel in cationic liposomes significantly increased the antitumoral efficacy of the drug. Remarkable microcirculatory changes indicate that encapsulation of paclitaxel in cationic liposomes resulted in a mechanistic switch from tumor cell toxicity to an antivascular therapy.
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PMID:Neovascular targeting chemotherapy: encapsulation of paclitaxel in cationic liposomes impairs functional tumor microvasculature. 1505 76

Previously, we identified angiogenic vessel-homing peptide Ala-Pro-Arg-Pro-Gly (APRPG), and showed that APRPG-modified liposomes could selectively target to tumor neovasculature. Here, we designed an APRPG-modified liposome encapsulating SU5416, an angiogenesis inhibitor, to overcome the solubility problem, and to enhance the antiangiogenic activity of SU5416. Liposomal SU5416 appeared to have the appropriate characteristics, such as particle size and stability in serum. It showed a significantly lower hemoglobin release than SU5416 dissolved in a Cremophor EL-containing solvent. Compared with peptide-unmodified liposomal SU5416, the APRPG-modified liposomal SU5416 significantly suppressed tumor growth and with no remarkable side effects. Thus, targeted delivery of antiangiogenic drugs with tumor vasculature-targeted liposomes may be useful for antiangiogenic cancer therapy.
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PMID:Antiangiogenic cancer therapy using tumor vasculature-targeted liposomes encapsulating 3-(3,5-dimethyl-1H-pyrrol-2-ylmethylene)-1,3-dihydro-indol-2-one, SU5416. 1855 91

A neovessel-targeted PEGylated liposomal formulation of paclitaxel was prepared with the purpose of improving the solubility of paclitaxel and specific targeting ability of this drug to tumor vasculature. AlphaV integrins overexpressed on the surface of new formed tumor vessels were selected to be the targets and their specific ligand, a 12-mer peptide containing a cyclic RGD sequence was used to achieve the goal. After coupled with a KGG-Palmitic acid conjugate, the RGD containing peptide was successfully integrated to the lipid bilayers. Mean particle size of the liposomes was under 100 nm and the drug entrapment efficiency was greater than 95%. Release study showed a much lower release rate of paclitaxel from liposomal formulation than from Cremophor EL-based formulation which indicated that this drug was stable in an entrapped form in vitro. Plasma distribution study showed that liposomal paclitaxel-treated groups obtained higher paclitaxel concentration than Taxol-treated group after 6 h injection. Greater cellular uptake was also found in the integrin-targeted liposomal paclitaxel-treated group compared with Taxol-treated group. Treatment of mice bearing A549 tumors with the integrin-targeted paclitaxel liposomes resulted in a lower tumor microvessel density than Taxol-treated group. Therefore, RGD-based strategy could be used to enhance tumor-specific recognition of nanocarriers. Neovessel-targeted PEGylated paclitaxel liposomes developed in present study might be a more promising drug for cancer treatment.
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PMID:Integrin-targeted paclitaxel nanoliposomes for tumor therapy. 2064 30