The influence of kidneys ion transport inhibitors on the pharmacokinetic and tumor uptake behaviors of a HER2-targeted small size radiolabeled peptide

BACKGROUND

HER2 over-expression plays a crucial role in the cancer treatment protocol. This study evaluates the effectiveness of kidney organic anion and cation transport inhibitors on the tumor uptake of 99mTc-HYNIC-(Ser)3-LTVPWY radiotracer in SKOV-3 tumor-bearing nude mice.

METHODS

Before the injection of the radiolabeled peptide, SKOV-3 tumor-bearing nude mice were treated with furosemide, cimetidine, para-amino hippuric acid, and saline. The inhibition effects of the organic anion and cation transport inhibitors were compared with the control group. In both treatment and control groups, the tumor and renal accumulation of radiopeptide in mice bearing SKOV-3 tumors were assessed in biodistribution and SPECT imaging studies.

RESULTS

The biodistribution and imaging results suggested that all treated groups showed a higher tumor and higher normal tissue radioactivity compared to the control group. According to the tumor imaging study, the furosemide-treated group had slightly better tumor uptake and a higher tumor to muscle uptake ratio than the other treatment groups.

CONCLUSIONS

Administration of furosemide (an OAT inhibitor) increased radioactivity accumulation in the kidneys and blood and improved tumor radioactivity uptake. PAH (an anion transporter substrate) and cimetidine (an OCT inhibitor) have a minor effect on the accumulation of radioactivity in the kidneys and the acquired images.