Epirubicin Loaded Super Paramagnetic Iron Oxide Nanoparticleaptamer Bioconjugate for Combined ColonCancer Therapy and Imaging In Vivo

Every year a large number of new cases of colorectal cancer are diagnosed in the world. Applicationof Epirubicin (Epi) in treatment of cancer has been limited due to its cardiotoxicity. Specific deliveryof chemotherapy drugs is an important factor in reducing the side effects of drugs used inchemotherapy. Enhanced permeability, retention effect and magnetic resonance (MR) traceability ofsuper paramagnetic iron oxide nanoparticles (SPION) make them a great candidate in cancer therapyand imaging. In this study, Epirubicin-5TR1 aptamer–SPION tertiary complex was evaluated for theimaging and treatment of murine colon carcinoma cells (C26 cells, target). For cytotoxic studies(MTT assay), C26 and CHO-K1 (Chinese hamster ovary cells, nontarget) cells were treated witheither Epi or Epi–Apt–SPION tertiary complex. Internalization was evaluated by flow cytometry.Finally, Apt-SPION bioconjugate was used for imaging of cancer in vivo. Flow cytometric analysisshowed that the tertiary complex was internalized effectively to C26 cells, but not to CHO-K1 cells.Cytotoxicity of Epi–Apt–SPION tertiary complex also confirmed internalization data. The complexwas less cytotoxic in CHO-K1 cells when compared to Epi alone. No significant change in viabilitybetween Epi- and complex-treated C26 cells was observed. Magnetic resonance imaging (MRI)indicated a high level of accumulation of the nano-magnets within the tumor site. In conclusion Epi–Apt–SPION tertiary complex is introduced as an effective system for targeted delivery of Epi to C26cells. Moreover, this complex could efficiently detect tumors when analyzed by MRI and inhibittumor growth in vivo.