摘要: 甲狀腺未分化癌的腫瘤細胞增殖迅速且易轉移,因為此類細胞失去凋亡調控機制而且迅速的去分化(De-differentaition),因此甲狀腺未分化癌的病人會因為癌細胞迅速增生轉移,平均存活超過六個月。我們於 1999年開始有關甲狀腺未分化癌的研究,早期我們使用腫瘤壞死因子(tumor necrosis factor-α, TNF-α)處理甲狀腺未分化癌的細胞株(ARO cell line),TNF-α可以誘導甲狀腺未分化癌細胞產生型態學上的分化現象。2001年起,我們開始降膽固醇藥物史達汀 (statins, lovastatin)處理甲狀腺未分化癌細胞的實驗,我們發現較低濃度(25μM)的史達汀可以誘導癌細胞產生再分化現象,但在較高濃度下(50 μM),則可以導致癌細胞產生細胞凋亡。其分子機轉都在於史達汀改變了細胞膜上的 G-蛋白,特別是 Rho,相關史達汀抑制細胞膜 G-蛋白質,降低甲狀腺未分化癌細胞的侵襲性的研究結果刊登於國外重要期刊 (J Clin Endocrinol & Metab、Endocrinology及 Endocrine Related Cancer)。2006 年我們進入裸鼠動物實驗模型,我們將 ARO細胞株植入裸鼠的皮下組織,並且在腫瘤成長後,我們發現使用 5及 10毫克/每公斤/每日時,史達汀可以明顯的抑制腫瘤生長,並使腫瘤萎縮,但是使用 1 毫克/每公斤/每日時,卻發生腫瘤明顯加速成長的現象,我們稱為『雙元效應』(duality effects) ,本研究成果已被 2010 International Journal of Cancer (IF: 6.198)。此外,我們使用蛋白質體學發現閥蛋白(FLOT1)是史達汀引導甲狀腺未分化癌細胞分化的重要控制因子,而本篇研究刊登於 2012 Journal of Proteomics (IF: 4.088)。基於戊糖磷酸途徑(PPP)為 phosphogluconate 通路/單磷酸己糖分流。PPP 的具體功能與脂質合成,以及將戊糖轉化成己糖有關。戊糖被尤其被認定是在哺乳動物細胞中為核酸的合成中的重要能量來源。Lovastatin 可以在不同濃度中,決定是否啟動轉酮脢。由於轉酮脢可以轉換果糖-6 -磷酸和甘油-3-磷酸、戊糖-5-磷酸和預防糖尿病併發症 erythrose- 4 -磷酸的產生,因此轉酮脢可能在發生癌症的機轉中扮演一定的角色。我們以 Lovastatin 及Oxythiamine 處理 ARO 及 SW579 細胞株,並以裸鼠模型證實 Lovastatin 合併使用Oxythiamine時,可藉由抑制轉酮脢(Transketolase, TKT),達成抑制活體動物 ARO細胞腫瘤抑制生長之結果。本實驗的結果,回答了兩個問題,首先 Lovastatin 在低劑量裸鼠腫瘤實驗時加速腫瘤之生長機轉為活化轉酮脢 TKT,此外我們也發現甲狀腺未分化癌的生長的過程導源於醣類代謝 Pentose Phosphate pathway途徑中的轉酮脢活化效應,而可以藉由氧化硫胺素 (Oxythiamine, OXT) 造成甲狀腺未分化癌的凋亡。進一步使用Oxythiamine (轉酮脢 TKT 之抑制劑)治療裸鼠腫瘤時,可以觀察到明顯的抑制腫瘤生長情況,而單獨使用 Lovastatin 之裸鼠 ARO 細胞腫瘤,確實會比 Control 組的腫瘤增長的更快,而當 Oxythiamine 介入與 Lovastatin 同步治療時,腫瘤生長明顯減緩。確認了Lovastatin 加速腫瘤之生長機轉為活化轉酮脢 TKT,也為甲狀腺未分化癌的治療發現了全新的治療途徑,就是抑制轉酮脢 TKT,並擬申請開發新藥治療分化不良型腫瘤之專利機轉,目前論文已預備投稿。又基於在甲狀腺細胞的分化中,Dipeptidyl peptidase-IV (DPP-IV, 二肽基肽酶-Ⅳ)只表現在甲狀腺癌細胞,正常的甲狀腺細胞並不會表現DPP-IV,我們使用 DPP-IV 的抑制劑 Vildagliptin 來誘導甲狀腺未分化癌細胞分化,目前以外泌體(Exosome) 之蛋白質體分析,發現在 ARO 全細胞蛋白質體分析時,Vildagliptine會增加 Sodium iodine symptor (NIS)的表現,但 ARO細胞外泌體蛋白質分析卻呈現抑制 NIS 表現的相反結果。我們預計在兩年的期間以蛋白質體學完成分析以Vildagliptin / Lovastatin /OXT 處理 ARO及 SW579 細胞後之外泌體(Exosome)蛋白質分析。預期找出甲狀腺未分化癌細胞產生去分化及再分化之生物標記及治療機轉。
Abstract: Anaplastic thyroid cancer (ATC) is a fatal malignancy, and it usually progressed rapidly with distant metastasis due to deficiency of apoptotic regulation with de-differentiation, and the average survival would be less than six months. Clinical practitioners knew that this disease canno be cured in combination with operation, radiotherapy and chemotherapy. We initially treated ATC cell line (ARO cells) with TNF-α, later the evidences of re-differentiation were firstly observed were also observed in ARO culture medium after treatment of lovastatin. Apoptosis could be found in ARO cells treated with higher concentrations, however, re-differentiation was noted in cells treated with lower concentrations (25 μM), while re-differentiation with higher concentration (50 μM). Molecular mechanism revealed that small G-protein (prenylated proteins) in cell membrane, especially for Rho. These results were published in Journal of Clinical Endocrinology & Metabolism, Endocrinology and Endocrine Related Cancer, respectively. In 2006, our animal model was carried out, nude mice implanting with ARO cells was established for lovastatin treatment. We found that tumor growth was prominent suppressed in nude mice treated with lovastatin, 5 and 10 mg/kg/day in comparison (higher dose) in comparison] with positive control group. Meanwhile, tumor growth was significantly promoted in mice treated with 1 mg/kg/day as unexpected finding. Lovastatin showed the “duality effects” for tumor apoptosis and progression. Such results were published in 2010 International Journal of Cancer (IF: 6.198). In addition, we use proteomic analysis to prove up-regulation of FLOT1 to be the pivotal role in re-differentiation of ATC cells. This finding was published in 2012 Journal of Proteomis (IF: 4.088). Based on pentose phosphate pathway(PPP), PPP is the shunt for phosphogluconate stream。PPP could play a role in synthesis of lipid in cells and transferring glucose to pentose. Pentose was recognized the energy resource for synthesis of nucleic acid in mammals. In our previous study, Lovastatin will activate transketolase (TKT) in ARO cells with dose-dependent manner. Therefore, TKT may play certain key role in tumorgenesis. Furthermore, we use lovastatin 及 oxythiamine(OXY, inhibitor of TKT) to treat ARO cells in cellular and nude mice model, we found that lovastatin together with OXY could inhibit ARO tumor growth in nude mice via suppressing the expression of TKT. We proved that lovastatin can accelerate ARO tumor growth in nude mice via activation of TKT in certain dose, in addition, OXY could inhibit expression of TKT to prohibit tumor growth in nude mice, via cellular apoptosis in cellular model. Under the fact of lovastatin could promote tumor growth via activation of TKT, but tumor growth will inhibited by OXY. We found one new therapeutic strategy in treating ATCvia inhibition of cellular expression of TKT. We prepared these results for publication and will enter the process of filing patent. On the other hand, Dipeptidyl peptidase-IV (DPP-IV) could be only express in follicular thyroid cancer, but not in normal thyrocytes. We now use DPP-IVinhibitor (Vildagliptin) in inducing re-differnetiationof ARO cells. However, we unexpectedly found that whole ARO cells and ARO cell-derived Exosomal proteomic analysis indicate Vildagliptine will increase expression of sodium iodine symptor (NIS) in whole cellular protein, but decrease the expression of NIS in cell-derived exosomal protein. In the very next two years, we will use cell-derived exosomal proteomic analysis in Vildagliptin / Lovastatin /OXT treated ARO and SW579 cells。We hope to find newly biological markers in predicting de-differentiation or re-differentiationin in thyroid cancer model, and enter the protocol of treatment in such ATC patients.