探討維生素A酸促使的神經母細胞瘤分化中IGFBP3和SOX6所扮演的角色

Abstract

神經母細胞瘤是一種高度惡性的孩童癌症，好發於腎上腺，常轉移到骨髓、淋巴結、或是肝臟等器官，根據分化程度上的差異有不同的亞型，患有分化較好的癌症的病人通常有較好的預後，高危險性的NB病人會接受清髓性的化學治療及持續性的給予維生素A酸(RA)來促使癌細胞分化。 首先我們藉由微陣列基因表現分析的方式來找尋可能與分化相關的基因，我們發現IGFBP3在細胞分化的同時它的表現量會上升以及Sox6在細胞分化之後表現量會下降，此篇研究的主要目的在於探討IGFBP3及Sox6在神經瘤細胞的生長及分化扮演甚麼樣的角色。首先我們在SK-N-DZ、SH-SY5Y和SK-N-SH這三株神經瘤細胞分別證實了微陣列分析的結果。在IGFBP3方面，我們發現添加RAR 抑制劑會抑制RA促進的IGFBP3上升，接著透過螢光素酶報告基因檢測系統確認IGFBP3的上升是透過RA直接結合導致。在細胞功能相關的實驗，我們發現IGFBP3會抑制細胞的增生，然而IGFBP3對於細胞侵犯並沒有看到顯著的影響。在病理組織切片染色的結果我們發現只有在分化較好的病人才能觀察到IGFBP3的表現。在Sox6方面，在臨床的部份我們透過免疫組織化學染色法證明Sox6在分化不良的神經母細胞瘤的表現量會有顯著的上昇以及Sox6高表現量高可預測病人低存活率。

Neuroblastoma (NB) is a highly malignant pediatric cancer that often arises from the adrenal glands. NB is also an aggressive cancer that has a potential to distant organs, such as bone marrow, lymph node, liver, and so on. The definition of different subtypes of NB depends on its differentiation state and the well-differentiated patients show better prognosis. Patients with high risk NB will accept myeloablative chemotherapy and retinoid acid (RA) treatment, which can induce differentiation persistently. We used microarray analysis to search the possible genes that induced after differentiation. We found that the expression level of IGFBP3 increased and that of Sox6 decreased during differentiation of NB cells. The aim of this study is to explore the role of IGFBP3 and Sox6 in the growth and differentiation of NB. First, we used three human NB cells, SK-N-DZ, SH-SY5Y, and SK-N-SH, to confirm the finding of microarray analysis. We found that the treatment of RAR inhibitor decreased the up-regulation of IGFBP3 induced by RA. Then we used a luciferase assay to show the increase of IGFBP3 level was though the directly binding of RA. Besides, we perform some experiments to explore cellular function. The results showed that IGFBP3 inhibit NB cell growth and proliferation but there is no significantly effect on cell migration. Furthermore, we observed the expression of IGFBP3 was seen only in well-differentiated ganglion cells of ganglioneruoma on the histopathological sections. On the other hand, we demonstrated a remarkable increase of Sox6 level in the poorly differentiated NB patients by immunohistochemical stain and Sox6 can be used as a potential marker to predict the survival rate of NB patients.