Abstract 4410: An ICAM-1-targeted, Lcn2 siRNA-encapsulating liposome as a potent anti-angiogenic agent for triple-negative breast cancer

Introduction: The significant growth and metastasis of triple negative breast cancer (TNBC) tumors, coupled with limited treatment options, have made TNBC a clinically challenging disease. We have previously shown that the intercellular adhesion molecule-1 (ICAM-1) is highly overexpressed in human TNBC tissues and cell lines, suggesting that ICAM-1 could be a potential TNBC molecular target. Lipocalin 2 (Lcn2), a 25-kDa protein belonging to the lipocalin protein superfamily. We have recently reported that Lcn2 is a regulator of angiogenesis. We have also found that down-regulation of TNBC-secreted Lcn2 is associated with reduced tumor angiogenesis in preclinical studies of breast cancer, making it a promising TNBC anti-angiogenic target. Here, we describe a novel liposomal drug delivery system that integrates TNBC targeting via ICAM-1, with Lcn2 siRNA silencing, to synergistically inhibit TNBC angiogenesis in vitro and in vivo, representing a novel anti-angiogenic therapeutic approach for the treatment of TNBC. Materials and Methods: ICAM-1 antibody, or non-targeted IgG conjugated, Lcn2 siRNA encapsulating liposomes (ICAM-Lcn2-LPs or IgG-Lcn2-LPs (non-targeting control)) were prepared by the extrusion method. Lcn2 siRNA silencing in TNBC cells was determined by qRT-PCR, and the anti-angiogenic functions of ICAM-Lcn2-LP were evaluated via a series of in vitro angiogenic assays including: endothelial cell proliferation, endothelial cell migration, and endothelial cell tube formation. These in vitro anti-angiogenic results were further confirmed in vivo using the chick chorioallantoic membrane (CAM) assay. Results: We have engineered a liposomal siRNA delivery system to target triple negative breast cancer (TNBC) via a novel molecular target, ICAM-1, and selectively silenced a TNBC-overexpressing angiogenic mediator, Lcn2 using siRNA. This ICAM-1 targeted, Lcn2 siRNA delivery liposome binds human TNBC MDA-MB-231 cells 3.1-fold greater than non-neoplastic MCF-10A cells. Potent Lcn2 knockdown by ICAM-Lcn2-LP led to a significant reduction in VEGF secretion by MDA-MB-231 cells, which led to reduced TNBC-induced angiogenesis both in vitro and in vivo. Conclusions: We have successfully engineered an immunoliposome that synergistically couples TNBC-targeting with Lcn2 siRNA silencing. Synthesized ICAM-Lcn2-LPs can significantly suppress in vitro and in vivo angiogenic activities of TNBC cells by regulating VEGF secretion. The modular design introduced here provides a basis for future TNBC-targeted therapeutics. Acknowledgements: This research is supported by NIH(NCI 1DP2CA174495) and the Breast Cancer Research Foundation. Citation Format: Peng Guo, Jiang Yang, Marsha Moses, Debra Auguste. An ICAM-1-targeted, Lcn2 siRNA-encapsulating liposome as a potent anti-angiogenic agent for triple-negative breast cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4410. doi:10.1158/1538-7445.AM2015-4410