1型胰岛素样生长因子受体在髓母细胞瘤细胞增殖中的作用

目的 研究1型胰岛素样生长因子受体(IGF-1R)在髓母细胞瘤中的表达及其对细胞增殖的作用.方法 荧光定量PCR检测髓母细胞瘤肿瘤标本IGF-1R表达,CCK-8法测定IGF-1R特异性阻断剂NVP-ADW742对髓母细胞瘤Doay细胞增殖抑制作用,并检测其对细胞凋亡的影响,Western blot免疫印迹法检测了 AKT磷酸化蛋白表达变化.结果 髓母细胞瘤肿瘤标本中的1GF-1R mRNA的相对含量明显高于低级别星形胶质瘤;NVP-ADW742能通过诱导细胞凋亡抑制Doay细胞的增殖,NVP-ADW742主要是通过卜凋AKT磷酸化蛋白表达而起作用.结论 IGF-IR在髓母细胞瘤的细胞增殖中起着重要作用.

The role of insulin-like growth factor 1 receptor in the cell proliferation of human medulloblastma

Objective Insulin-like growth factors and their receptor (IGF-1 R) have been implicated in cancer pathophysiology. The purpose of this study was to investigate the IGF-1R expression in medulloblastoma, and determine the mechanism of action of IGF-IR in the cell proliferation. Method The brain tumor sample of 13 medulloblastoma and 8 low grade astrocytoma were freshly collected from surgical specimen. Total cell RNA was isolated with Trizol. The IGF-IR mRNA was determined by real-time quantitative RT-PCR using SYBR Green. Doay cell line was cultured in Eagle's MEM supplemented with 10% fetal bovine serum. Fluorescence intensity of IGF-1R staining was determined using flow cytometer in Doay cell line. Doay cells were treated with the indicated concentration of specific IGF-IR kinase inhibitor, NVP-ADW742, in 96-well culture plates for 48 hours. Then cell Counting CCK-8 was used to each well for 2 hours. Absorbance readings at a wavelength of 450 nm and reference wavelength of 650 nm were taken on a spectrophotometer. Doay cells were incubated in the presence of different concentration of NVP-ADW742 and apoptotic rate was determined by flow cytometry using annexin V. The phospho-AKT protein was detected by Western blot in Doay cells exposed with NVP-ADW742. Results The relative level of IGF-IR mRNA expression was significantly higher than that in low grade astrocytoma. Flow cytometer showed that the cell surface protein IGF-1R expressed in medulloblastoma cell line Doay. Exposure of Doay cells to NVP-ADW742 in different concentration resulted in significant growth inhibition of Doay cells. And the results showed that a dose-dependent proliferation inhibitation was demonstrated in Doay cells. Western blotting detection showed that phospho-AKT protein decreased in Doay cells upon NVP-ADW742 treatment. Conclusions The expression of IGF-1R plays an important role in development of medulloblastoma by promoting abnormal tumor cellular proliferation. NVP -ADW742 inhibits IGF-1-mediated receptor activation and the induction of apoptosis by NVP-ADW742 in Doay cells might due to the downregulation of phospho-AKT protein.