CXCL12/CXCR4轴在胰腺癌-神经交互作用中的研究

The role of CXCL12/CXCR4 axis in interaction between pancreatic cancer and neural cells

目的本研究旨在阐述CXCLl2/CXCR4轴对胰腺癌神经相互作用的影响,探讨CXCLl2/CXCR4在胰腺癌嗜神经过程中的相关分子机制。方法体外培养胰腺癌Panc-1、Miapaca-2细胞,实验分为空白对照组、外源性CXCLl2组及CXCR4受体特异性阻断剂AMD3100组。采用RT-PCR检测胰腺癌细胞CXCR4及CXCL12mRNA的表达,检测基质金属蛋白酶-2(matrix metalloproteinase-2,MMP-2)、基质金属蛋白酶-9(matrix metalloproteinase-9,MMP-9)及人尿激酶型纤溶酶原激活物(human urokinase plasminogen activator,uPA)mRNA的表达;采用Transwell侵袭实验观察各实验组中细胞侵袭性的变化;提取大乳鼠脊髓背根神经节,建立胰腺癌细胞Miapaca-2与脊髓背根神经节(DRG)共培养模型,倒置显微镜成像系统动态观察不同实验组中神经轴突生长差异。结果胰腺癌细胞Panc-1、Miapaca-2细胞存在CXCR4mRNA的表达,而CXCL12mRNA无表达;两种胰腺癌细胞之MMP-2、MMP-9及uPAmRNA在AMD3100组、对照组、CXCLl2组中的表达差异具有统计学意义(P<0.01);Transwell细胞侵袭性实验中,外源性CXCLl2明显增强Panc-1、Miapaca-2细胞的侵袭性,而AMD3100有效抑制肿瘤细胞的侵袭能力,组间存在显著差异(P<0.05)。胰腺癌细胞与脊髓背根神经节共培养模型中,外源性CXCLl2明显增强神经轴突的生长,促使胰腺癌细胞与神经轴突接触,而AMD3100有效抑制神经轴突生长及与肿瘤细胞接触;细胞共培养144h后各组神经生长轴突数差异有统计学意义(P<0.01)。结论 CXCLl2/CXCR4一方面增强胰腺癌细胞的侵袭能力,促进胰腺癌细胞神经浸润;另一方面,神经元与施万细胞等构成神经纤维分泌CXCL12并通过化学趋化作用,诱导表达CXCR4的胰腺癌细胞向神经迁移,导致神经浸润的发生。

Objective To illustrate the role and possible molecular mechanism of CXCL12/CXCR4 axis in the interaction between pancreatic cancer and neural cells. Methods Different pancreatic cancer cells(Panc-1 and Miapaca-2) cultured in vitro were harvested and divided into CXCL12 group,AMD3100 group(CXCR4 antagonist) and control group.RT-PCR was applied to investigate the mRNA expressions of CXCR4,CXL12,matrix metalloproteinases(MMPs) and human urokinase plasminogen activator(uPA).Transwell invasion assay was applied to analyze the invasive ability of tumor cells in different groups.Co-culture between tumor cells and dorsal root ganglia(DRG) cells was applied to analyze the perineural invasion(PNI) of pancreatic cancer in different groups. Results The mRNA expression of CXCR4 was observed in pancreatic cancer cells and DRG,but CXCL12 was found only in DRG cells.CXCL12 significantly increased the expressions of MMP-2,MMP-9 and uPA(P<0.01) in pancreatic cancer cells,which could strengthen the invasive ability of pancreatic caner;however,CXCR4 antagonist AMD3100 could inhibit the phenomenon.CXCL12 group,CXCR4 antagonists group and control group differed significantly(P<0.05).Co-culture study showed that more growth of axon and PNI was observed in CXCL12 group than in control group(P<0.05).Additionally,AMD3100 inhibited the growth of axon and PNI. Conclusion CXCLl2/CXCR4 axis can increase the invasive ability of pancreatic cancer cells and induce neural invasion of pancreatic cancers.Additionally,CXCL12 derived from neural cells and Schwann cells may cause the CXCR4 positive pancreatic cancer cells to move toward the neural cells,inducing neural infiltration.