Synthesis of a cell penetrating peptide modified superparamagnetic iron oxide and MRI detection of bladder cancer.

Chen Ding,Li Liu,Zhenfeng Guan,Rong Wang,Weiyi Wang,Xinyang Wang,Lei Wang,Jinhai Fan,Kaijie Wu

doi:10.18632/oncotarget.13578

Abstract

Bladder cancer is the most common malignancy of the urinary tract for which the accurate measurement of minimal residual disease is critical to treatment and determining prognosis. Although cystoscope examination and voided urine cytology remain the current standard of care for detecting residual disease, these approaches are limited by mechanical trauma and lack sensitivity. To develop a new accurate noninvasive method, we developed a novel contrast agent where the surface of superparamagnetic iron oxide (SPIO) nanoparticles is functionalized with a bladder cancer-specific fluorescein isothiocyanate (FITC) labeled cell penetrating peptide (CPP)-polyarginine peptides (R11) for active targeting and imaging. The stable nanoparticles have an average hydrodynamic diameter of 51 nm, surface charge of -21 mV and MRI r2 relaxivity 135 mM−1s−1. In vitro cell studies demonstrated that the R11-conjugated SPIO (SPIO-R11) nanoparticles were taken up by bladder cancer cells (T24) in a dose-dependent manner, which was higher than unconjugated SPIO. TEM showed that SPIO-R11 was mainly concentrated on cell vesicle and lysosome, not in cell nucleus, and no obvious damage was seen on cell ultrastructure. Moreover, uptake of the nanoparticles showed significantly more SPIO-R11 accumulation in bladder cancer cells than in immortalized bladder epithelial cells unlike control SPIO. Further, SPIO-R11 was compatible with immortalized bladder epithelial cells at all tested concentrations up to 200 μg/mL after 72 h incubation. Moreover, SPIO-R11 decreased the magnetic resonance T2 relaxation time by 73% in tumors cells in vitro compared to 12% with SPIO. These results indicate great potential of SPIO-R11 as contrast agent to target bladder cancer for diagnostic and therapeutic applications.

Highlights

Bladder urothelial cell carcinoma (UCC), the 9th most common cancer diagnosis worldwide [1], is the most common malignancy of the urinary tract
To develop a new accurate noninvasive method, we developed a novel contrast agent where the surface of superparamagnetic iron oxide (SPIO) nanoparticles is functionalized with a bladder cancer-specific fluorescein isothiocyanate (FITC) labeled cell penetrating peptide (CPP)-polyarginine peptides (R11) for active targeting and imaging
In vitro cell studies demonstrated that the R11-conjugated SPIO (SPIO-R11) nanoparticles were taken up by bladder cancer cells (T24) in a dose-dependent manner, which was higher than unconjugated SPIO

Summary

INTRODUCTION

Bladder urothelial cell carcinoma (UCC), the 9th most common cancer diagnosis worldwide [1], is the most common malignancy of the urinary tract. With the help of SPIO, MRI has made great progress in studying gene and drug delivery, cell trafficking, tumor diagnosis, cancer-targeted therapy and many other fields [8, 16,17,18,19]. Among these SPIO contrast agents, dextran- or carboxydextran-coated SPIO nanoparticles are the most commonly used and clinically approved such as Feridex or Resovist [20]. We describe the development of a bladder-specific-peptides-conjugated SPIO (SPIO-R11) for use in targeted cancer imaging with MRI, investigating its synthesis and characterization, cytotoxicity, ability to enter bladder cancer cells in vitro, and the effectiveness as a MR contrast agent

RESULT

DISCUSSION

Findings

MATERIALS AND METHODS