Investigation using an HER‐2/neu transgenic mouse model of a newly developed MR contrast agent with the effect of an antitumor drug

Abstract

To assess whether Gd-DTPA-Gel-Cis, a conjugate of gadolinium (Gd), cis diamminedichloroplatinum (Cis), diethylenetriaminepentaacetic acid (DTPA)-dianhydride, and bovine gelatin (Gel) can be used as an intravascular contrast agent at MRI and as an antitumor cell proliferation agent in vitro. We injected Gd-DTPA-Gel-Cis (200 mg/mL) into the caudal vein of female HER-2/neu transgenic mice with spontaneous mammary tumors. The tumor signal intensity was measured with a 0.3 Tesla MRI scanner. HER-2/neu-expressing NT cells were treated with Gd-DTPA-Gel-Cis (5 microM cisplatin, 200 mg/mL Gel), Cis alone (5 microM cisplatin), or Gel alone (200 mg/mL gelatin). Differences of P < 0.05 were considered to be statistically significant. On T1-weighted MRI scans of mice injected with Gd-DTPA-Gel-Cis we observed a 23% increase in signal intensity. The survival rates of cells exposed to Gd-DTPA-Gel-Cis or Cis were 70.9% and 58.3%, respectively, of the survival rates observed after treatment with Gel alone. Gd-DTPA-Gel-Cis showed significant toxicity (P < 0.05). Gd-DTPA-Gel-Cis shows promise for use as an MRI contrast medium and as an antitumor agent.