Anticancer research
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Anticancer research · Jun 2009
Improvement of biodistribution and therapeutic index via increase of polyethylene glycol on drug-carrying liposomes in an HT-29/luc xenografted mouse model.
Liposomes modified with a high concentration of polyethylene glycol (PEG) could significantly prolong the retention time of the carried drug in the circulation, thus improving the drug accumulation in the tumor. In this study, 6 mol% rather than 0.9 mol% PEGylated liposomes (100 nm in diameter) encapsulated with indium-111 were used in a human colorectal carcinoma HT-29/luc tumor-bearing mouse model for comparing the PEGylation effect. Pharmacokinetics, biodistribution, passive-targeted assay, bioluminescence imaging (BLI) and tumor growth measurements were used for the spatial and temporal distribution, tumor localization and therapeutic evaluation of the drug. ⋯ Gamma scintigraphy at 48 h post injection also demonstrated more distinct tumor uptake with 6 mol% PEG (111)In liposomes as compared to that of 0.9 mol% PEGylated liposomes (p<0.01). BLI and in vivo tumor growth tracing showed that growth in tumor volume could largely be inhibited by 6 mol% PEG (111)In liposomes. The results suggest that 6 mol% PEGylated liposomes might be a more suitable liposomal carrier for drug delivery than 0.9 mol% PEGylated liposomes, not only by reducing the drug accumulation in the RES or its related organs, but by prolonging drug circulation and eventually enhancing the targeting efficiency in the tumor to reach a better therapeutic index.
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Anticancer research · Jun 2009
Combination of PI3K/mTOR inhibition demonstrates efficacy in human chordoma.
Chordomas are rare tumors of the axial skeleton for which surgical resection remains the most reliable means of cure. PI-103 is a inhibitor of PI3K/AKT and mTOR activation. This study aims to determine whether the PI3K/mTOR pathway was active in chordomas and whether their inhibition could lead to decreased proliferation and increased apoptosis. ⋯ The PI3K/AKT and mTOR signaling pathway is constitutively activated in chordoma. PI-103 decreases proliferation and induces apoptosis in the UCH-1 via inhibition of the PI3K/mTOR pathway.