The labeling of 188Re-MN-16ET/Lipiodol and preliminary study in hepatocellular carcinoma animal model

Objectives The major goal of study is to evaluate the therapeutic potential of a new radiopharmaceutical ¹⁸⁸Re-MN-16ET/Lipiodol in hepatocellular carcinoma animal model. ¹⁸⁸Re is an attractive radioisotope emitting 2.12 MeV β particles to result in the damage of cancer cell.MN-16 ET, (succinimidy-3,6-diaza-5-oxo -3-[2-((triphenylmethyl)thio)ethyl]-8-[(triphenylmethyl)thio]octanoate), is a new chemical ligand which was designed and synthesized by INER.It was used to conjugate with ¹⁸⁸Re and dissolved in Lipiodol, and we can get the compound ¹⁸⁸Re-MN-16ET/Lipiodol. The HCC animal model by inoculating with tumor cell N1-S1 on the liver of SD rats to perform the biodistribution study.

Methods The radiochemical purity of ¹⁸⁸Re-MN-16ET/Lipiodol, checked by TLC was more than 95%. The hepatoma-implanted rats (n=15) were injected with 0.1mCi/0.1ml of ¹⁸⁸Re-MN-16ET/Lipiodol through TAE separately. The rats were sacrificed at 1, 24 and 48 hours post-injection. Five rats were left to take the distribution image using SPECT.

Results The biodistribution data showed that ¹⁸⁸Re-MN-16ET/Lipiodol could accumulate at the tumor site. It was 11.55±1.44,13.16±1.46,and 10.67±0.95 respectively in 1, 24 and 48 hours. However, the excretion of ¹⁸⁸Re-MN-16ET/Lipiodol in the normal tissue was progressively decreased. From SPECT images, ¹⁸⁸Re-MN-16ET/Lipiodol is mainly distributed at liver in 48 hours.

Conclusions The data showed that ¹⁸⁸Re-MN-16ET/Lipiodol has the potential to be a therapeutic radiopharmaceutical for liver cancer treatment. We still need to perform more advanced studies to prove its efficacy.