sepantronium and Thyroid-Neoplasms

Anaplastic thyroid cancer (ATC) is among the most aggressive of human cancers, and currently there are few effective treatments for most patients. YM155, first identified as a survivin inhibitor, was highlighted in a high-throughput screen performed by the National Cancer Institute, killing ATC cells in vitro and in vivo. However, there was no association between survivin expression and response to YM155 in clinical trials, and YM155 has been mostly abandoned for development despite favorable pharmacokinetic and toxicity profiles. Currently, alternative mechanisms are being explored for YM155 by a number of groups. In this study, ATC patient samples show overexpression of topoisomerase Top2α compared with benign thyroid samples and to differentiated thyroid cancers. ATC cell lines that overexpress Top2α are more sensitive to YM155. We created a YM155-resistant cell line, which shows decreased expression of Top2α and is resensitized with Top2α overexpression. Molecular modeling predicts binding for YM155 in the Top2α ATP-binding site and identifies key amino acids for YM155-Top2α interaction. A Top2α mutant abrogates the effect of YM155, confirming the contribution of Top2α to YM155 mechanism of action. Our results suggest a novel mechanism of action for YM155 and may represent a new therapeutic approach for the treatment of ATC.

Topics: Adenosine Triphosphate; Apoptosis; Binding Sites; Cell Death; Cell Line, Tumor; DNA Damage; Humans; Imidazoles; Inhibitor of Apoptosis Proteins; Naphthoquinones; Survivin; Thyroid Carcinoma, Anaplastic; Thyroid Neoplasms

Anaplastic thyroid cancer (ATC) is one of the most lethal malignancies with a median survival time of about 4 months. Currently, there is no effective treatment, and the development of new therapies is an important and urgent issue for ATC patients. YM155 is a small molecule that was identified as the top candidate in a high-throughput screen of small molecule inhibitors performed against a panel of ATC cell lines by the National Cancer Institute. However, there were no follow-up studies investigating YM155 in ATC. Here, we determined the effects of YM155 on ATC and human primary benign thyroid cell (PBTC) survival with alamarBlue assay. Our data show that YM155 inhibited proliferation of ATC cell lines while sparing normal thyroid cells, suggesting a high therapeutic window. YM155-induced DNA damage was detected by measuring phosphorylation of γ-H2AX as a marker for DNA double-strand breaks. The formamidopyrimidine-DNA glycosylase (FPG)-modified alkaline comet assay in conjunction with reactive oxygen species (ROS) assay and glutathione (GSH)/glutathione (GSSG) assay suggests that YM155-mediated oxidative stress contributes to DNA damage. In addition, we provide evidence that YM155 causes cell cycle arrest in S phase and in the G2/M transition and causes apoptosis, as seen with flow cytometry. In this study, we show for the first time the multiple effects of YM155 in ATC cells, furthering a potential therapeutic approach for ATC.

Topics: Apoptosis; Cell Cycle Checkpoints; Cell Line, Tumor; Cell Proliferation; Cell Survival; DNA Damage; Humans; Imidazoles; Naphthoquinones; Oxidative Stress; Reactive Oxygen Species; Signal Transduction; Thyroid Carcinoma, Anaplastic; Thyroid Gland; Thyroid Neoplasms

Follicular thyroid carcinoma's (FTC) overall good prognosis deteriorates if the tumour fails to retain radioactive iodine. Therefore, new druggable targets are in high demand for this subset of patients. Here, we investigated the prognostic and biological role of survivin and XIAP in FTC. Survivin and XIAP expression was investigated in 44 FTC and corresponding non-neoplastic thyroid specimens using tissue microarrays. Inhibition of both inhibitor of apoptosis proteins (IAP) was induced by shRNAs or specific small molecule antagonists and functional changes were investigated in vitro and in vivo. Survivin and XIAP were solely expressed in FTC tissue. Survivin expression correlated with an advanced tumour stage and recurrent disease. In addition, survivin proved to be an independent negative prognostic marker. Survivin or XIAP knockdown caused a significant reduction in cell viability and proliferation, activated caspase3/7 and was associated with a reduced tumour growth in vivo. IAP-targeting compounds induced a decrease of cell viability, proliferation and cell cycle activity accompanied by an increase in apoptosis. Additionally, YM155 a small molecule inhibitor of survivin expression significantly inhibited tumour growth in vivo. Both IAPs demonstrate significant functional implications in the oncogenesis of FTCs and thus prove to be viable targets in patients with advanced FTC.

Topics: Adenocarcinoma, Follicular; Animals; Biomarkers, Tumor; Cell Line, Tumor; Cell Survival; Disease Models, Animal; Female; Gene Expression; Gene Knockout Techniques; Humans; Imidazoles; Immunohistochemistry; Male; Mice; Naphthoquinones; Neoplasm Staging; Prognosis; Survivin; Thyroid Neoplasms; X-Linked Inhibitor of Apoptosis Protein; Xenograft Model Antitumor Assays

Anaplastic thyroid cancer (ATC) is a rare but lethal malignancy without any effective therapy. The aim of this study is to use a high-throughput drug library screening to identify a novel therapeutic agent that targets dysregulated genes/pathways in ATC.. We performed quantitative high-throughput screening (qHTS) in ATC cell lines using a compound library of 3,282 drugs. Dysregulated genes in ATC were analyzed using genome-wide expression analysis and immunohistochemistry in human ATC tissue samples and ATC cell lines. In vitro and in vivo studies were performed for determining drug activity, effectiveness of targeting, and the mechanism of action.. qHTS identified 100 active compounds in three ATC cell lines. One of the most active agents was the first-in-class survivin inhibitor YM155. Genome-wide expression analysis and immunohistochemistry showed overexpression of survivin in human ATC tissue samples, and survivin was highly expressed in all ATC cell lines tested. YM155 significantly inhibited ATC cellular proliferation. Mechanistically, YM155 inhibited survivin expression in ATC cells. Furthermore, YM155 treatment reduced claspin expression, which was associated with S-phase arrest in ATC cells. In vivo, YM155 significantly inhibited growth and metastases and prolonged survival.. Our data show that YM155 is a promising anticancer agent for ATC and that its target, survivin, is overexpressed in ATC. Our findings support the use of YM155 in clinical trials as a therapeutic option in advanced and metastatic ATC.

Topics: Adaptor Proteins, Signal Transducing; Animals; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Cell Survival; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Genome-Wide Association Study; HeLa Cells; Humans; Imidazoles; Immunohistochemistry; Inhibitor of Apoptosis Proteins; Inhibitory Concentration 50; Mice; Naphthoquinones; Neoplasm Metastasis; RNA, Small Interfering; S Phase; Survivin; Thyroid Carcinoma, Anaplastic; Thyroid Neoplasms; Treatment Outcome