乏氧环境下HO-1诱导表达对乳腺癌MDA-MB-231细胞侵袭迁移的调控作用研究

目的:研究乏氧对人乳腺癌MDA-MB-231细胞侵袭及迁移能力的影响，并研究血红素氧合酶-1(heme oxygenase-1，HO-1)在这一过程中的作用，初步探讨其作用机制。方法:利用RNA干扰技术，抑制乳腺癌MDA-MB-231细胞中HO-1的表达，得到HO-1表达受干扰的细胞系MDA-MB-231-HO-1△。通过Transwell迁移、侵袭实验分别检测常氧及乏氧条件下MDA-MB-231-NC细胞（HO-1正常表达）和MDA-MB-231-HO-1△细胞（HO-1干扰表达）迁移、侵袭能力的变化，Western blot检测乏氧条件下两组乳腺癌细胞的上皮和间质标记物的表达，检验细胞系是否发生了上皮-间质转化(epithelial-mesenchymal transition，EMT)。结果:乏氧培养24小时后，MDA-MB-231-NC 细胞中HO-1蛋白表达水平显著升高，MDA-MB-231-HO-1△细胞中HO-1表达受抑制。乏氧培养后MDA-MB-231-NC细胞的侵袭、迁移能力较常氧培养的细胞明显增强，其差异具有统计学意义(P<0.05)；而MDA-MB-231-HO-1△细胞侵袭、迁移能力在乏氧和常氧培养下无显著差异。乏氧条件下，MDA-MB-231-NC细胞的上皮标志物E-cadherin表达显著下调，间质标志物Vimentin表达显著上调，而MDA-MB-231-HO-1△细胞的E-cadherin、Vimentin表达无明显变化。结论:乏氧条件下乳腺癌MDA-MB-231细胞中HO-1可被诱导高表达，促进了细胞的侵袭迁移，其可能机制是促进了乳腺癌细胞上皮-间质转化。

Regulatory effect of HO-1 induced expression under hypoxia environment on the invasion and migration of breast cancer MDA-MB-231 cells

Objective:To investigate the effect of hypoxia on the invasion and migration capacities of human breast cancer MDA-MB-231 cells，examine the role of heme oxygenase-1 (HO-1) in this process，and preliminarily explore its mechanism of action.Methods:HO-1 expression in breast cancer MDA-MB-231 cells was suppressed using RNA interference technique to obtain the HO-1 suppressed cell line MDA-MB-231-HO△.Changes in the migration and invasion capacities of MDA-MB-231-NC cells (with normal HO-1 expression) and MDA-MB-231-HO-1△ cells (with suppressed HO-1 expression) under normoxia and hypoxia conditions were detected through Transwell migration and invasion assays，respectively.Meanwhile，expression of epithelium and mesenchyme markers in both groups of breast cancer cells under hypoxia condition was detected through Western blot assay，so as to detect whether the cell line had developed epithelial-mesenchymal transition (EMT).Results:After 24 h of hypoxic culture，the HO-1 protein expression level in MDA-MB-231-NC cells was markedly increased，while HO-1 expression in MDA-MB-231-HO-1△ cells was suppressed.After hypoxic culture，the invasion and migration capacities of MDA-MB-231-NC cells were remarkably enhanced compared with those cultured under normoxia condition，and the difference was statistically significant (P<0.05).The invasion and migration capacities of MDA-MB-231-HO-1△ cells displayed no significant difference between hypoxia and normoxia conditions.Under hypoxia condition，the expression of epithelial marker E-cadherin was evidently down-regulated in MDA-MB-231-NC cells，while that of mesenchymal marker Vimentin was outstandingly up-regulated.Meanwhile，the expression of E-cadherin and Vimentin in MDA-MB-231-HO-1△ cells showed no obvious change.Conclusion:High HO-1 expression can be induced in breast cancer MDA-MB-231 cells under hypoxia condition，which can promote cell invasion and migration，and the potential mechanism may be related to promoting EMT in breast cancer cells.