Abstract 4343: Therapeutic efficacy of different double arms polyethyleneglycol-modified liposome containing doxorubicin on pulmonary metastasis.

Abstract

Abstract [Purpose] Metastasis is responsible for most mortality in cancer therapy. Important things of metastatic treatment are not only prevention but also therapy of metastatic tumor. It was indicated that usability of liposomal doxorubicin (DOX) as drug delivery system formulation which were modified with 1,2-distearoyl-sn-glycero-3-phosphoethanolamine dipolyethyleneglycol(different double arms PEG; DDA-PEG) (DDA-LDOX). DDA-PEG had two different PEG lengths, 2000 and 500, in one molecule. In this study, the effect of DDA-LDOX was examined on pulmonary metastasis compared with 1-monomethoxy-PEG(2000)-2,3-distearoylglycerol (PEG2000-DSG) modified liposomal DOX (2000-LDOX).[Methods] The liposomal DOX was prepared by L-α-distearoylphosphatidylcholine, cholesterol, L-α-distearoylphosphatidyl-DL-glycerol and DOX (100:100:60:18 μmol). Liposomal DOX was added 7.5 μmol DDA-PEG or 15 μmol PEG2000-DSG. In anti-metastasis experiment, BDF1 mice were transplanted B16F10 melanoma cells by intravenous inoculation and each liposome (2.5 mg/kg, DOX) was injected at 20, 23 and 26 day after tumor transplantation. After 48 hr from last administration, the mice were dissected and score of pulmonary metastasis was recorded (0∼10, 0: normal). Removed tissues were determined DOX concentration by fluorescence method. In vitro, it was examined DOX uptake into B16F10 melanoma cells from each liposome. [Results and Discussion] Pulmonary metastasis scores of control and 2000-LDOX were 6.5 and 2.6, respectively. In contrast, that of DDA-LDOX was 1.0. Relative pulmonary weight (%) was correlation with metastatic score (R2=0.954) and supported pulmonary metastasis score. DOX concentration of DDA-LDOX was twice higher than that of 2000-LDOX in the lung, namely, it was proved that DDA-LDOX was easy to accumulate in the lung. Especially, it was suggested that DDA-LDOX accumulated into pulmonary metastatic site because DOX concentrations of heart, spleen and kidney were equal level in other group. In the examination of DOX uptake into tumor cells, DOX level in DDA-LDOX group was significantly higher than that in 2000-LDOX group. The data had supported high accumulation into pulmonary metastasis in vivo. In conclusion, it was suggested that DDA-LDOX was useful drug carrier for suppressed pulmonary metastasis since it could have target ability to pulmonary metastasis. Citation Format: Ikumi Sugiyama, Yasuyuki Sadzuka. Therapeutic efficacy of different double arms polyethyleneglycol-modified liposome containing doxorubicin on pulmonary metastasis. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4343. doi:10.1158/1538-7445.AM2013-4343