The anti-tumor effect evaluation and mechanistic investigation of reversine on thyroid cancer cell lines
Date Issued
2010
Date
2010
Author(s)
Hua, Shih-Che
Abstract
Background:
Thyroid cancer is the most common cancer among endocrine malignancies. Although current management with surgical resection followed by radioactive iodine therapy has been proved effective in treating differentiated thyroid cancer, but there have been no available effective treatment modalities for metastatic radio-resistant differentiated thyroid cancer and anaplastic thyroid cancer. Aneupolidy represents a hallmark of solid cancers including thyroid cancer and is associated with poor prognosis. Aurora kinases (Aur) are important kinases in the regulation of normal cell cycle, which are overexpressed in various type of cancer cells and aurora kinases inhibition will suppress tumor growth. Currently, several Aur inhibitors are undergoing clinical trials. Thyroid cancer has also been proved to have Aur overexpression which is related to undifferentiated phenotypes. Recently, a small synthetic molecule named reversine, a purine analogue, has proved anti-tumor effective in acute myeloid leukemia cells and multiple myeloma cells. However, up to date, there has been no study aimed at thyroid cancer treatment by reversine.
Objective and hypothesis:
Because of the current clinical treatment dilemma in incurable differentiated thyroid cancer, poorly differentiated thyroid cancer or anaplastic thyroid cancer, a novel and effective treatment modality is urgently needed. We propose reversine could suppress thyroid cancer tumor growth by inducing cell cycle arrest and cell apoptosis.
Methods:
First, we in vitro examined the anti-tumor effects of reversine on human anaplastic thyroid cancer cell line (ARO), human follicular thyroid cancer cell line (WRO), and human poorly-differentiated thyroid cancer cell line (SW579) by MTT assay; simultaneously, we in vivo examined the anti-tumor effects of reversine on ARO by xenograft nude mice model; if anti-tumor effects proved, we further investigated reversine’s effects on cell cycle and cell death by flow cytometry analysis. If apoptosis is proved by flow cytometry, to clarify the apoptotic signal transduction pathway, further activated caspase 3, caspase 8, and caspase 9 would be detected by western blot. Pan-caspase inhibitor would be tested its ability to reverse cell death caused by reversine.
Results:
Reversine suppressed these 3 thyroid cancer lines (ARO, WRO, SW579) growth in vitro, although with different susceptibility, e.g. well-differentiated WRO cells more resistant to reversine. Only ARO xenograft nude mice model was successfully established. Reversine was also validated to suppress ARO tumor growth in vivo, but the anti-tumor was not in a dose-dependent manner. In the aspect of cell cycle analysis, these 3 thyroid cancer cells treated by reversine were shown G2/M phase arrest. In the aspect of cell death analysis, apoptotic ratio increased in a time and dose-dependent manner in these 3 thyroid cancer cell lines, but also with different susceptibility. SW579 cells treated by reversine were susceptible to apoptosis, but neither ARO nor WRO cells. SW579 cells treated by reversine activated caspase 8 and capase 3, not caspase 9. And cell death after treatment of reversine was attenuated by pan-caspase inhibitor.
Conclusion:
This study is the first to prove anti-tumor effects of reversine on thyroid cancer cell lines in vitro and in vivo. Besides, we investigated reversine’s anti-tumor mechanisms. Reversine inhibits ARO and WRO cells mainly by cell cycle progression arrest. However, reversine inhibits SW579 cells mainly by cell cycle arrest and inducing cell apoptosis. The apoptotic mechanisms were via mitochondria-independent extrinsic pathway. Reversine is a novel potential anti-thyroid cancer drug and may enter clinical trials in the future.
Subjects
thyroid cancer
cycle cycle
apoptosis
xenograft nude mice
SDGs
Type
thesis
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