Simple modifications to methimazole that enhance its inhibitory effect on tumor necrosis factor-α-induced vascular cell adhesion molecule-1 expression by human endothelial cells

The expression of vascular cell adhesion molecule-1 (VCAM-1) on the vascular endothelium can be increased by pro-inflammatory cytokines [e.g. tumor necrosis factor-α (TNF-α)]. VCAM-1 contributes to leukocyte adhesion to, and emigration from, the vasculature which is a key aspect of pathological inflammation. As such, a promising therapeutic approach for pathological inflammation is to inhibit the expression of VCAM-1. Methimazole [3-methyl-1, 3 imidazole-2 thione (MMI)] is routinely used for the treatment of Graves׳ disease and patients treated with MMI have decreased levels of circulating VCAM-1. In this study we used cultured human umbilical vein endothelial cells (HUVEC) to investigate the effect of MMI structural modifications on TNF-α induced VCAM-1 expression. We found that addition of a phenyl ring at the 4-nitrogen of MMI yields a compound that is significantly more potent than MMI at inhibiting 24h TNF-α-induced VCAM-1 protein expression. Addition of a para methoxy to the appended phenyl group increases the inhibition while substitution of a thiazole ring for an imidazole ring in the phenyl derivatives yields no clear difference in inhibition. Addition of the phenyl ring to MMI appears to increase toxicity as does substitution of a thiazole ring for an imidazole ring in the phenyl MMI derivatives. Each of the compounds reduced TNF-α-induced VCAM-1 mRNA expression and had a functional inhibitory effect, i.e. each inhibited monocytic cell adhesion to 24h TNF-α-activated HUVEC under fluid flow conditions. Combined, these studies provide important insights into the design of MMI-related anti-inflammatory compounds.

Abstract 1932: Phenylmethimazole decreases constitutively high basal levels of Interleukin 6 (IL-6) in a triple negative breast cancer cell line

Interleukin 6 (IL-6) is a pro-inflammatory cytokine that plays an important role in the progression of many types of cancers by regulating macrophage recruitment and differentiation, as well as modulating the activation of the JAK/Stat signal cascade, and inducing pro-angiogenic factors. Several studies have correlated a negative prognosis in cancer with a high level of IL-6 in patient serum. Triple (i.e. progesterone, human epidermal growth factor-2, and estrogen receptor) negative breast cancer has been reported to be highly aggressive and invasive. MDA-MB-231, a triple negative breast cancer cell line, expresses high basal levels of IL-6. Recently our laboratory demonstrated that phenylmethimazole (C10), a novel toll-like receptor inhibitor, diminishes basal expression of IL-6 in pancreatic cancer and melanoma cells as well as their growth and migration. Based on these observations, we sought to test the hypothesis that C10 inhibits IL-6 expression in MDA-MB-231 cells. Here we report that triple negative breast cancer cells express considerably higher levels of IL-6 than estrogen receptor positive breast cancer cells and that C10 significantly reduces IL-6 expression in the triple negative breast cancer cells. This inhibition was observed at both the RNA and protein level. Given the importance of IL-6 in cancer progression, and our finding that C10 attenuates IL-6 expression in the MDA-MB-231 cell line, this study suggests that C10 may have therapeutic potential for triple negative breast cancers. Additional studies are currently underway to further explore these hypotheses.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1932. doi:1538-7445.AM2012-1932