Abstract 3629: Development of Combrestatin loaded vascular cell modified CLENS for targeting cellular models of tumor vascular endothelia in vitro

Purpose: The American Cancer Society predicts that about 0.6 million people would die of cancer and about 1.7 million new cases will be diagnosed in the year 2018. One important goal of cancer treatment is to minimize uptake of the cytotoxic drug agent by normal tissues. CLENs (cell membrane lipid-extracted nanoliposomes) have been developed to enhance targeted delivery of drugs to cancer cells located in the tumor interstitial matrix environment. The purpose of this study was to evaluate the use of CLENs for tumor vascular targeting. Methods: We expanded tumor endothelial cells derived from the pancreas followed by membrane extraction and the development of MS1-VEGF CLENs for vascular targeting. We evaluated the benefits of the additional inclusion of conventional liposome components (DOPC/Chol/DPPE-PEG5000) in various ratios, including the synthetic cationic lipid DOTAP (50 mol%), known for its vascular targeting characteristics when employed with conventional liposome components. We performed cellular uptake studies to determine relative level of selectivity in connection with the inclusion of LE (lipid extract) material. We determined also the effect of the additional inclusion of DOTAP in CLENs for targeting. We separated free drug from drug incorporated in CLENs using dialysis cassettes with MWCO of 10 kD. We evaluated the efficiency of Combrestatin A4 Phosphate (a microtubule-destabilizing agent) loading in CLENs by HPLC. Results: The addition of (50 mol%) cationic lipid DOTAP content in CLENs increased the overall zeta potential of the preparation from -14.26 ± 3.65 mV to 10.24 ± 4.23 mV. The average particle size for MS1-VEGF CLENs was approximately 137 ± 7 nm. The cellular uptake studies revealed that CLENs consisting of 70 mol% LE demonstrated the greatest selectivity towards MS1 VEGF cells, when compared to minimal uptake observed for non-target human glioblastoma (U87-MG) cell control. However, the data suggest also an overwhelming cationic lipid effect when DOTAP was included in the CLENs. Where overall cellular uptake increased, the selectivity afforded by LE decreased. Preliminary drug loading studies (between 20 and 45%) suggested that LE inclusion in nanoliposomes influenced the capacity for drug loading. Conclusion: The inclusion of MS1-VEGF lipid extract material in nanoliposomes improved vascular selectivity. The additional inclusion of DOTAP enhanced targeting, but the preference for target versus non-target cells had diminished. Additional studies are currently underway. Citation Format: Kanchi S. Sanghvi, Robert Campbell, Guang Yan. Development of Combrestatin loaded vascular cell modified CLENS for targeting cellular models of tumor vascular endothelia in vitro [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3629.