Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0035412 (rhabdomyosarcoma)
 6,156 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The role of vascular permeability in the preferential accumulation of photosensitizers in tumor tissue was investigated. Two murine tumors [experimental mammary tumor carcinoma (EMT-6) and methylcholanthrene-induced rhabdomyosarcoma (M1S)] and a human bladder carcinoma (EJ) were grown s.c. on the flank in athymic nude mice and analyzed for in vivo vessel permeability, vascular permeability factor (VPF) secretion, and accumulation of the photosensitizer, chloroaluminum sulfonated phthalocyanine. In vivo tumor vessel permeability and vascular volume were quantitated by measuring Evans blue extravasation and accumulation of a high molecular weight fluoresceinated dextran, respectively. VPF was isolated from serum-free tumor cell conditioned medium using heparin-Sepharose affinity chromatography. Dot and Western blots stained with anti-VPF antiserum positively identified VPF in samples from each tumor. Chloroaluminum sulfonated phthalocyanine pharmacokinetics in tumor-bearing mice were measured using a fiber-based spectrofluorometer. In vivo vessel permeability was found to be greatest in M1S tumors, next in EMT-6 tumors and finally in EJ tumors. Consistent with in vivo data, M1S and EMT-6 tumor cells in culture secrete significantly more VPF than EJ tumor cells. Chloroaluminum sulfonated phthalocyanine accumulation was approximately 2 times greater in M1S and EMT-6 tumors compared to EJ tumors. Our data present evidence that photosensitizer accumulation can be correlated to in vivo tumor vessel permeability and VPF secretion of that tumor. Taken together, the data support the hypothesis that vascular permeability differences among tumors play a significant role in the uptake and retention of photodynamic agents.
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PMID:Tumor-secreted vascular permeability factor/vascular endothelial growth factor influences photosensitizer uptake. 841 39

We have previously demonstrated that vascular endothelial growth factor-165 (VEGF), a tumor-secreted angiogenic factor, can acutely and chronically induce fenestrations in microvascular endothelium (Cancer Res 1997, 57:765-772). Because the morphology and function of microvascular endothelium differs from tissue to tissue, we undertook studies to examine whether the neovasculature in tumors also differed depending upon tumor location. Four tumor types implanted in the brain or subcutis in nude mice were studied: a murine rhabdomyosarcoma (M1S), a murine mammary carcinoma (EMT), and two human glioblastomas (U87 and U251). In addition, we studied Chinese hamster ovary cells stably transfected with human VEGF165. As previously reported, tumors grown in the subcutaneous space had a microvasculature that was fenestrated and had open endothelial gaps. The identical tumors when grown in the brain also had fenestrated endothelium and vessels with open endothelial gaps, but they were drastically reduced in occurrence. Open endothelial gaps were not seen in all tumors implanted in the brain (EMT and M1S), although fenestrated endothelium was always seen. VEGF and VEGF receptors were measured in tumors from both locations by immunoblotting and competitive polymerase chain reaction, respectively. VEGF amount was not significantly different between the tumor locations. Interestingly, total tumor vascular mRNA expression of both Flk-1 and Flt-1 was greater in tumor vessels derived from the brain compared with tumor vessels derived from subcutaneous tissues. These results demonstrate that the host microvascular environment determines the morphology and function of the tumor vasculature and that endothelia from different tissues vary in their ability to express the VEGF receptors given identical stimuli.
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PMID:Host microvasculature influence on tumor vascular morphology and endothelial gene expression. 977 55