Contents lists available at ScienceDirect European Journal of Pharmaceutics and Biopharmaceutics journal homepage: www.elsevier.com/locate/ejpb Research paper Efficacy of a novel LyP-1-containing self-microemulsifying drug delivery system (SMEDDS) for active targeting to breast cancer Selin S. Timur a , Diğdem Yöyen-Ermiş b,1 , Güldal Esendağlı c , Selcen Yonat c , Utku Horzum b , Güneş Esendağlı b , R. Neslihan Gürsoy a, ⁎ a Department of Pharmaceutical Technology, Faculty of Pharmacy, Hacettepe University, Ankara, Turkey b Department of Basic Oncology, Hacettepe University Cancer Institute, Ankara, Turkey c Department of Medical Pathology, Faculty of Medicine, Gazi University, Ankara, Turkey ARTICLE INFO Keywords: Breast cancer LyP-1 p32 SMEDDS Lymphatic targeting Chemotherapy ABSTRACT An ideal cancer therapy targets the tumor cells selectively without damaging healthy tissues. Even though the tumor-specific markers are limited, these molecules can be used for the delivery of anti-cancer drugs as an active targeting strategy. Since the lymphatic system plays a critical role in the dissemination of cancer cells, the drugs directed through lymphatics can feasibly reach to the sites of metastasis. LyP-1 is a peptide that binds to the p32 receptor which is highly expressed not only on the lymphatic endothelium but also on the malignant cells; thus, making this peptide ligand a preferable candidate to mediate active targeting of lymphatics and cancer cells. In this study, different formulations of LyP-1 containing lipid-based nanopharmaceutics so-called self-micro- emulsifying drug delivery systems (SMEDDS) were developed and tested for their efficacy in targeting breast cancer. Following the selection of non-toxic formulation, doxorubicin hydrochloride and LyP-1 were co-ad- ministered in the SMEDDS, which resulted in a significant increase in in vitro cytotoxicity in p32-expressing breast cancer cells, 4T1 and MDA-MB-231. Accordingly, the uptake of LyP-1 in the SMEDDS by the cancer cells was demonstrated. The expression of p32 was detected in the 4T1 tumor tissues which were efficiently targeted with LyP-1 in the SMEDDS. When doxorubicin was co-administrated with LyP-1 in SMEDDS via intraperitonial administration, tumor growth and metastasis were significantly reduced. In conclusion, a novel and efficacious SMEDDS formulation containing LyP-1 with a droplet size less than 100 nm was developed for the lymphatic targeting of breast cancer. 1. Introduction The real challenge of conventional anticancer therapy is to over- come the undesirable collateral damage on healthy tissues, especially with high renewal capacity [1]. Thus, studies that adopted a passive or active therapy approach aim to selectively and effectively deliver the drugs into the tumor [2]. The receptors on the surface of tumor cells can be targeted by the drug delivery systems bearing specific ligands. These approaches not only enable the delivery of low dose chemotherapeutics but also ensure the effectiveness [3]. The lymphatic system plays crucial roles in homeostasis, lipid ab- sorption and immune response, albeit serving as a path for the meta- static spread of cancer cells [4]. Thus, lymphatics has become a pre- ferable target for anti-cancer drug delivery systems [5–8]. LyP-1 is a nonapeptide (CGNKRTRGC) with an ability to bind its specific receptor p32 (gC1qR/HABP), which can be highly found on tumor-related lymphatics, macrophages, and cancer cells [9,10]. Elevated levels of p32 is found on the surface of cancer cells while it is intracellularly expressed in normal cells; therefore, p32 found on cancer cells and lymphatic endothelium is more accessible by LyP-1 [9,11–13]. In addition to its tumor homing abilities, LyP-1 can deteriorate the viability of MDA-MB-435 breast cancer cells in a dose-dependent manner. Repeated administration of LyP-1 was shown to hamper the tumor progression and the development of new lymphatics in the tu- mors established with MDA-MB-435 [10]. Accordingly, LyP-1 has be- come a preferred molecule for the active targeting of cancer and lym- phatics in cancer diagnosis and treatment studies. This peptide has been used in formulations prepared with liposomes [14–17], dendrimers [18,19], microbubbles [20–22], SMEDDS [23], micelles [24,25], na- noparticles [11,26–32], and mesoporous nanospheres [33]. https://doi.org/10.1016/j.ejpb.2019.01.017 Received 13 September 2018; Received in revised form 2 January 2019; Accepted 16 January 2019 ⁎ Corresponding author. E-mail address: ngursoy@hacettepe.edu.tr (R.N. Gürsoy). 1 Current address: Medical Biology Department, Faculty of Medicine, Lokman Hekim University, Ankara, Turkey. European Journal of Pharmaceutics and Biopharmaceutics 136 (2019) 138–146 Available online 22 January 2019 0939-6411/ © 2019 Elsevier B.V. All rights reserved. T