神经节苷脂对整合素α2β1介导神经母细胞瘤细胞粘附于胶原蛋白的影响

目的：目的探讨内生肿瘤神经节苷脂（gangliosides, Gls）对整合素α2β1介导神经母细胞瘤细胞与胶原蛋白(collagen, Col)粘附反应的影响。方法：用葡萄糖苷神经酰氨合成酶抑制剂(D-threo-1-phenyl-2-decaolamino-3morphinoline-1-propanol, D-PDMP）抑制SK-N-SH细胞株Gls合成，采用流式细胞仪检测清除肿瘤细胞Gls前后SK-N-SH细胞整合素α2β1（integrin α2β1）表达的变化情况，同时观察Mg2+、抗integrin α2单克隆抗体6F1和抗integrin β1单克隆抗体(anti-β1) 对该细胞对包被Col粘附作用的影响，所粘附的细胞用BCA方法测定，以吸光度（A570）代表粘附细胞的数量。结果：SK-N-SH细胞高水平表达integrin α2β1。暴露于D-PDMP 6 d后，细胞Gls几乎完全清除，但integrin α2β1的表达无明显变化，Mg2+能明显增加SK-N-SH细胞I型Col的粘附反应，Mg2+浓度为1 mmol/L的条件下，Gls清除组粘附能力较对照组的明显下降：A570分别为0.33±0.016和0.57±0.033（P<0.01）。用从SK-N-SH细胞提取的Gls加入Gls清除组，可明显恢复该细胞的粘附能力，较对照组差异无显著性（P>0.05）。 抗整合素α2β1单克隆抗体anti-α2（10 μL/mL）6F1和anti-β1均能显著阻断SK-N-SH细胞粘附于胶原蛋白(A570分别为 0.31± 0.018和0.36± 0.021)；但外源性肿瘤Gls并不能恢复anti-α2或anti-β1所阻断Gls清除组细胞的粘附能力。结论：内生肿瘤Gls增加整合素α2β1介导肿瘤细胞对Col的粘附作用，肿瘤Gls不能改变细胞 integrin的表达，Gls 对细胞粘附的调节作用主要可能通过影响细胞整合素的功能而发挥作用。［中国当代儿科杂志，2007，9（1）：42-46］

Effect of endogeneous gangliosides on integrin α2β1-mediated adhesion of neuroblastoma cells to collagen

OBJECTIVE: To study the effect of endogeneous gangliosides (Gls) on integrin alpha2beta1-mediated adhesion of neuroblastoma cells to collagen (Col). METHODS: Neuroblastoma SK-N-SH cell line was cultured in the modified eagle's medium with the presence of 10 mum D-threo-1-phenyl-2-decanolamino-3-morphinolin-1-propanol (D-PDMP), an inhibitor of glucosylceramide synthase. Flow cytometry was used to detect the expression of integrin alpha2beta1 in the cell line. The effects of Mg2(+) and monoclonal antibodies to integrin alpha2beta1 on the adhesion of the cell line to immobilized Col were observed. The adhesion cell number was measured with the BCA method and presented with absorptance A570. RESULTS: There was a high expression of integrin alpha2beta1 in the SK-N-SH cell line without D-PDMP treatment. Endogenous Gls in the cells were almost depleted after 6-day exposure to D-PDMP, but the integrin alpha2beta1 expression was not significantly changed. 1 mmoL/L Mg2(+) treatment increased significantly the number of adhesion cells in the SK-N-SH cell line. The adhesion to Col of the SK-N-SH cells exposed to D-PDMP which Gls was depleted was significantly reduced compared with the control SK-N-SH cells treated with 1 mmoL/L Mg2(+) (A570: 0.33 +/- 0.016 vs 0.57 +/- 0.033; P < 0.01). After endogeneous Gls was added into the Gls-depleted SK-N-SH cells, the adhesion of the cells was restored (A570: 0.52 +/- 0.035). The adhesion of SK-N-SH cells was significantly blocked by anti-alpha2 and anti-beta1 monoclonal antibodies, with A570 of 0.31 +/- 0.018 and 0.36 +/- 0.021 respectively. CONCLUSIONS: Endogenous tumor Gls increases neuroblastoma cell adhesion to Col by regulating the function of integrin alpha2beta1, but has no effects on the integrin expression. It is suggested that tumor Gls may play a role in migration, invasion and metastasis of tumor cells.