International Journal of Biological Macromolecules 78 (2015) 112–121 Contents lists available at ScienceDirect International Journal of Biological Macromolecules j ourna l ho me pa g e: www.elsevier.com/locate/ijbiomac Oral delivery of nanoparticles containing anticancer SN38 and hSET1 antisense for dual therapy of colon cancer M. Dinarvand a , M. Kiani a , F. Mirzazadeh a , A. Esmaeili a , Z. Mirzaie b , M. Soleimani c , R. Dinarvand a,b , F. Atyabi a,b,∗ a Department of Pharmaceutical Nanotechnology, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran 1714614411, Iran b Nanotechnology Research Centre, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran c Department of Hematology, School of Medical Sciences, Tarbiat Modares University, Tehran, Iran a r t i c l e i n f o Article history: Received 11 January 2015 Received in revised form 18 March 2015 Accepted 31 March 2015 Available online 6 April 2015 Keywords: Nanoparticles Oral drug delivery Chitosan a b s t r a c t An oral delivery system intended for treatment of colon cancer in HT29 cancerous cells was investigated by encapsulating hSET1 antisense and SN38 anticancer in nanoparticles based on cysteine trimethyl chi- tosan (cysTMC) and carboxymethyl dextran (CMD). Studies have shown hSET1 as the main type of histone methyltransferase (HMT) complex, is significantly overexpressed in malignant cells. In this study, hSET1 antisense was employed to inhibit gene expression. Additionally, SN38 was incorporated into nanopar- ticles to enhance the efficiency of the system by inhibition of topoisomerase 1. CysTMC was synthetized and characterized by 1 H NMR and FTIR. Nanoparticles were prepared through complexation of CMD and cysTMC. Particle size and surface charge was 100–150 nm and 17–21 mV respectively with drug content of around 2.6%. Gel electrophoresis assay proved the stability of antisense in simulated gastric and intesti- nal fluids. Nanoparticles showed high mucoadhesion and glutathione responsive release. Cellular uptake was observed by confocal microscopy and quantified by flow cytometry. Cytotoxicity of NPs was assessed using MTT assay. Results showed hSET1/SN38 nanoparticles had significantly higher cytotoxicity against HT29 cells compared with nanoparticles containing SN38, free SN38 or naked hSET1. Therefore, present system could be considered an effective combination therapy of highly hydrophobic SN38 and hSET1. © 2015 Elsevier B.V. All rights reserved. 1. Introduction Recent studies have highlighted the importance of epigenetic changes in formation of cancer cells. These epigenetic changes may contribute to unregulated gene expression, mutations and more importantly the silencing of tumor suppressors, genes responsible for apoptosis, or other DNA repair pathways [1]. Histone methyl- transferase (HMT) enzymes as post-translational histone modifiers, are mostly responsible for epigenetic regulations [2]. It has been discovered that hSET1 as the main type of HMT complex is sig- nificantly over-expressed in malignant cells [3]. HMT enzymes are responsible for histone methylation, specifically at the position of lysine 4 on histone 3 (H3K4) [4]. Yadav et al. [3] in a study suggested that inhibition of hSET1 caused apoptosis of tumor-cells in vitro. ∗ Corresponding author at: Faculty of Pharmacy, Tehran University of Medical Sciences, Nanomedicine, Enghelab St., Teheran, Iran. Tel.: +98 21 66959052; fax: +98 21 66959052. E-mail address: atyabifa@tums.ac.ir (F. Atyabi). In vivo studies also showed remission of implanted colon cancer xenografts. Gene expression could be successfully manipulated at the post translational level by degradation of mRNA. Because of its encour- aging therapeutic features, mRNA silencing has been extensively researched in recent years. The major ways to promote gene silenc- ing are the induction of siRNA, RNA, shRNA or antisense into the cells [5]. In this method a single strand oligonucleotide specifically binds to its complementary mRNA, prevents translation of a spe- cific gene and later promotes mRNA degradation [6]. Antisense therapy is particularly attractive in treatment of cancers, neu- rodegenerative and autoimmune diseases. The use of nucleic acid macromolecules to promote gene silencing although very attrac- tive, poses many obstacles for gene therapy [7]. First, a nucleic acid macromolecule is highly unstable in physiological media, rapidly degrades by endonucleases of plasma and is quickly eliminated by liver. Moreover, as a negatively charged macromolecule, it has minimal uptake by the negatively charged cellular membrane. Designing a proper carrier based delivery system is required to overcome these hurdles. Among proposed carriers, the applica- tion of positively charged polymers is widely studied because of http://dx.doi.org/10.1016/j.ijbiomac.2015.03.066 0141-8130/© 2015 Elsevier B.V. All rights reserved.