Henshaw Joshua, Mossop Brian, Yuan Fan
Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA.
Mol Cancer Ther. 2008 Aug;7(8):2566-73. doi: 10.1158/1535-7163.MCT-08-0435.
Pulsed electric fields have been shown to enhance interstitial transport of plasmid DNA (pDNA) in solid tumors in vivo. However, the extent of enhancement is still limited partly due to the collagen component in extracellular matrix. To this end, effects of collagen remodeling on interstitial electrophoresis were investigated by pretreatment of tumor-bearing mice with a recombinant human relaxin (rh-Rlx). In the study, two tumor lines (4T1 and B16.F10) were examined and implanted s.c. to establish two murine models: dorsal skin-fold chamber (DSC) and hind leg. Effects of rh-Rlx on pDNA electrophoresis were measured either directly in the DSC model or indirectly in the hind leg model via reporter gene expression. It was observed that rh-Rlx treatment reduced collagen levels in the hind leg tumors but not in the DSC tumors. The observation correlated with the results from electromobility experiments, where rh-Rlx treatment enhanced transgene expression in 4T1 hind leg tumors but did not increase the electromobility of pDNA in the DSC tumors. In addition, it was observed that pDNA binding to collagen could block its diffusion in collagen gel in vitro. These observations showed that effects of rh-Rlx on the collagen content depended on microenvironment in solid tumors and that rh-Rlx treatment would enhance electric field-mediated gene delivery only if it could effectively reduce the collagen content in collagen-rich tumors.
脉冲电场已被证明可增强体内实体瘤中质粒DNA（pDNA）的间质转运。然而，增强程度仍然有限，部分原因是细胞外基质中的胶原蛋白成分。为此，通过用重组人松弛素（rh-Rlx）对荷瘤小鼠进行预处理，研究了胶原蛋白重塑对间质电泳的影响。在该研究中，检查了两种肿瘤细胞系（4T1和B16.F10），并将其皮下植入以建立两种小鼠模型：背部皮肤褶皱腔室（DSC）和后腿模型。通过在DSC模型中直接测量或在后腿模型中通过报告基因表达间接测量rh-Rlx对pDNA电泳的影响。观察到rh-Rlx处理降低了后腿肿瘤中的胶原蛋白水平，但未降低DSC肿瘤中的胶原蛋白水平。该观察结果与电动迁移实验的结果相关，其中rh-Rlx处理增强了4T1后腿肿瘤中的转基因表达，但未增加DSC肿瘤中pDNA的电动迁移率。此外，观察到pDNA与胶原蛋白的结合可在体外阻断其在胶原蛋白凝胶中的扩散。这些观察结果表明，rh-Rlx对胶原蛋白含量的影响取决于实体瘤中的微环境，并且只有当rh-Rlx处理能够有效降低富含胶原蛋白的肿瘤中的胶原蛋白含量时，才会增强电场介导的基因递送。
