UCL Discovery

Abstract

Intra-arterial Lipiodol has been used to deliver targeted therapies to primary, and some metastatic, liver cancers. Targeted radiotherapy has been used by substituting the iodine in Lipiodol with (131)Iodine (I-131). Early clinical results are encouraging, but the variable response may partly depend on local pharmacokinetics. This study evaluated the in vitro cytotoxic effects of I-131-Lipiodol on human hepatocellular carcinoma (Hep-G2), human colorectal metastatic cancer (SW620), human colorectal hepatic cancer (LoVo) and human umbilical vein endothelia[ cells (HUVEC) cell lines. The cell cultures were exposed to I-131-Lipiodol for 48 h, following which cell counts and viability were assessed by haemocytometer, S-Rhodamine uptake and radioactivity assay. The effect of exposure to control Lipiodol, I-131-Lipiodol and I-131 alone was evaluated. I-131-Lipiodol was cytotoxic against all the cancer cell lines but not against the non-malignant (HUVEC) cell line. The cytotoxicity effects were Very similar in all the cancer cell lines. There were no cytotoxic effects following exposure to plain I-131 in any of the cell lines (malignant and non-malignant). A similar trend was seen with radioactivity counts using a gamma counter. The cytotoxic effect of I-131-lipiodol had a graded effect with an increase in cytotoxicity following the increase in the radioactive dose. This study showed that there was a marked cytotoxic effect by I-131-Lipiodol on all the cancer cell lines. There was no difference between the controls and the (131)Iodine. This suggests that effective I-131-Lipiodol targeted therapy is dependent on the uptake and retention of Lipiodol by malignant cells.