Interventional therapy for human breast cancer in nude mice with ¹³¹I gelatin microspheres ( ¹³¹I-GMSs) following intratumoral injection

Abstract

Introduction

The aim of this study was to investigate the effects of ¹³¹I gelatin microspheres ( ¹³¹I-GMS) on human breast cancer cells (MCF-7) in nude mice and the biodistribution of ¹³¹I-GMSs following intratumoral injections.

Methods

A total of 20 tumor-bearing mice were divided into a treatment group and control group and received intratumoral injections of 2.5 mci ¹³¹I-GMSs and nonradioactive GMSs, respectively. Tumor size was measured once per week. Another 16 mice received intratumoral injections of 0.4 mci ¹³¹I-GMSs and were subjected to single photon emission computed tomography (SPECT) scans and tissue radioactivity concentration measurements on day 1, 4, 8 and 16 postinjection. The 20 tumor-bearing mice received intratumoral injections of 0.4 mci [ ¹³¹I] sodium iodide solution and were subjected to SPECT scans and intratumoral radioactivity measurements at 1, 6, 24, 48 and 72 h postinjection. The tumors were collected for histological examination.

Results

The average tumor volume in the ¹³¹I-GMSs group on post-treatment day 21 decreased to 86.82 ± 63.6%, while it increased to 893.37 ± 158.12% in the control group ( P < 0.01 vs. the ¹³¹I-GMSs group). ¹³¹I-GMSs provided much higher intratumoral retention of radioactivity, resulting in 19.93 ± 5.24% of the injected radioactivity after 16 days, whereas the control group retained only 1.83 ± 0.46% of the injected radioactivity within the tumors at 1 h postinjection.

Conclusions

¹³¹I-GMSs suppressed the growth of MCF-7 in nude mice and provided sustained intratumoral radioactivity retention. The results suggest the potential of ¹³¹I-GMSs for clinical applications in radiotherapy for breast cancer.