¹¹¹In–L–LDL and ¹⁵³Gd–L–LDL as radiotracers for detection of AR4‐2J rat pancreatic tumors

Abstract

Pancreatic cancer has an extremely poor prognosis, due, in part, to lack of methods for early diagnosis. The present study was designed to evaluate the potential of labeling low-density lipoprotein (LDL) with a radionuclide using a lipid chelating agent, bis(stearylamide) of diethylenetriaminepentaacetic acid (L), to detect pancreatic tumors by gamma-scintigraphy. Previous studies indicated that the difficulty of visualization of pancreatic tumors was due to their poor vascularization. This study compares the ability of two radiotracers, 111 In-L-LDL and 153 Gd-L-LDL to target highly vascularized rat pancreatic tumors (AR4-2J) implanted in nude mice. Biodistribution studies showed that the tumor uptake of 111 In-L-LDL and 153 Gd-L-LDL tracers was twofold and fivefold higher respectively than with the controls ( 111 In citrate and 153 Gd citrate respectively). These tracers would thus be suitable for scintigraphic imaging.We show here that LDL could be employed as a delivery system for tracers such as 111 In or 153 Gd when these two radionuclides are complexed by a lipid-chelating anchor, and that 111 In-L-LDL and 153 Gd-L-LDL enabled better visualization of the pancreatic tumor tissues, with a better result with 153 Gd-L-LDL.