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Background: RX-0201 is an antisense oligonucleotide (ASO) against Akt1 currently in clinical trial for metastatic renal cancer. Purpose: To improve the delivery of RX-0201 using folate receptor-targeted lipid-albumin nanoparticles (F-LAN). Methods: F-LAN were synthesized with the composition of DOTAP/soyPC/TPGS/folate-PEG-DSPE (25:70:4:1 m/m), a cationic human serum albumin-pentaethylenehexamine (HSA-PEHA) conjugate and RX-0201. The nanoparticles were evaluated in KB human carcinoma cells in vitro and in a KB murine xenograft tumour model in vivo for pharmacokinetics and antitumor activities. Results: The F-LAN-RX-0201 had a mean particle size of 108.6 ± 5.8 nm, zeta potential of 10.5 ± 3.2 mV and ASO loading efficiency of 71.5 ± 4.5%. In KB cells, uptake and Akt1 inhibition by F-LAN-RX-0201 were greater than those of non-targeted LAN-RX-0201 and could be partially blocked by excess free folate. F-LAN-RX-0201 inhibited cell growth with an IC50 of 11.9 μM. In contrast, LAN-RX-0201 showed lower cytotoxicity with an IC50 of 32.0 μM. No significant cytotoxicity was observed with up to 250 µM of free RX-0201. Pharmacokinetic studies showed that F-LAN-RX-0201 had a longer terminal half-life than free RX-0201 (442 vs. 219 min). In a KB xenograft tumour model, F-LAN-RX-0201 exhibited greater tumour inhibition than LAN-RX-0201 at 16 mg/kg. Moreover, F-LAN-RX-0201 at 16 mg/kg showed comparable tumour inhibition compared to free RX-0201 at a much higher dose of 90 mg/kg. Conclusions: F-LAN-RX-0201 showed promise as a therapeutic agent for tumours with elevated folate-receptor expression. [ABSTRACT FROM AUTHOR]

Abstract: A novel liposomal formulation of paclitaxel targeting the folate receptor (FR) was synthesized and characterized. This formulation was designed to overcome vehicle toxicity associated with the traditional Cremophor EL-based formulation and to provide the added advantages of prolonged systemic circulation time and selective targeting of the FR, which is frequently overexpressed on epithelial cancer cells. The formulation had the composition of dipalmitoyl phosphatidylcholine/dimyristoyl phosphatidylglycerol/monomethoxy-polyethylene glycol (PEG)2000-distearoyl phosphatidylethanolamine/folate-PEG3350-distearoyl phosphatidylethanolamine (DPPC/DMPG/mPEG-DSPE/folate-PEG-DSPE) at molar ratios of (85.5:9.5:4.5:0.5) and a drug-to-lipid molar ratio of 1:33. The liposomes were prepared by polycarbonate membrane extrusion. The mean particle size of the liposomes was 97.1nm and remained stable for at least 72h at 4°C. FR-targeted liposomes of the same lipid composition entrapping calcein were shown to be efficiently taken up by KB oral carcinoma cells, which are highly FR+. FR-targeted liposomes containing paclitaxel showed 3.8-fold greater cytotoxicity compared to non-targeted control liposomes in KB cells. Plasma clearance profiles of paclitaxel in the liposomal formulations were then compared to paclitaxel in Cremophor EL formulation. The liposomal formulations showed much longer terminal half-lives (12.33 and 14.23h for FR-targeted and non-targeted liposomes, respectively) than paclitaxel in Cremophor EL (1.78h). In conclusion, the paclitaxel formulation described in this study has substantial stability and favorable pharmacokinetic properties. The FR-targeted paclitaxel formulation is potentially useful for treatment of FR+ tumors and warrants further investigation. [Copyright &y& Elsevier]

Abstract: Folate polyethylene glycol-cholesterol hemisuccinate (folate-PEG-CHEMS) is a novel folate ligand firstly synthesized by our group and demonstrated good stability and potential targeting results on KB cells in vitro. The current study further explored endocytosis mechanisms of liposomes via folate receptor on L1210JF cells and assessed targeted therapeutic efficacy of folate-PEG-CHEMS anchored liposomes loading daunorubicin (F-L-DNR) in vivo. Folate-PEG-CHEMS was synthesized by a modified method. The liposome properties, cell cytotoxicity, intracellular and intratumoral localization, and therapeutic efficacy on a murine tumor model bearing L1210JF cells were evaluated. High encapsulation efficiency (95.1%±1.5%) and appropriate particle size (76.0±35.5nm) and zeta potential (−12.83±1.36mV) were achieved for F-L-DNR. IC50 of F-L-DNR on L1210JF cells was 2–3-folds lower than that of non-targeted liposomal daunorubicin (L-DNR). Anticancer efficacy on L1210JF tumor model indicated that mice survival time of F-L-DNR group at doses of 5mg/kg and 10mg/kg was significantly longer than that of L-DNR or free DNR. Confocal fluorescence photographs of F-L-DNR indicated enhanced endocytosis of liposomes via folate receptor on L1210JF cells, prolonged retaining time in tumors and improved drug release in the tumor site at 24h post intravenous injection of F-L-DNR. In conclusion, folate-PEG-CHEMS is an effective ligand for folate-targeted daunorubicin liposomes to achieve increased drug release in tumor and therapeutic efficacy. [Copyright &y& Elsevier]