"Star" miR-34a and CXCR4 antagonist based nanoplex for binary cooperative migration treatment against metastatic breast cancer

Invasion and metastasis of tumor cells is one of the major obstacles in cancer therapy. The process of tumor metastasis and diffusion is coordinated by multiple pathways associated with chemokine signals and migration microenvironment. In our previous work, chemokine CXC receptor 4 (CXCR4) antagonists showed significant anti-metastatic effects by blocking the CXCR4/stromal cell-derived factor-1(SDF-1) axis in pancreatic cancer and breast cancer. Here, we proposed to achieve migration chain-treatment for metastatic tumors by introducing a cell adhesion molecules CD44 inhibitor (Star miR-34a) to deprive of cell migration capability on the basis of CXCR4 antagonism (cyclam monomer, CM). Dextrin modified 1.8 k PEI with CM-end was prepared to deliver therapeutic miR-34a (named DPC/miR-34a) for efficient anti-metastasis by downregulating adhesion protein CD44 and targeting the CXCR4/SDF-1 axis. Additionally, reduced expression of the anti-apoptotic protein Bcl2 caused by miR-34a could enhance the anti-tumor efficacy of DPC/miR-34a nanoplex administration. Compared with inhibition of the CXCR4/SDF-1 axis or CD44 expression, the multidimensional therapy (DPC/miR-34a) exhibited considerable suppression of cancer cell invasion as assessed by an in vitro cell invasion assay and in vivo anti-metastasis model. Moreover, DPC/miR-34a demonstrated a superior antitumor and anti-metastatic efficacy both in lung metastatic model and orthotopic MDA-MB-231 tumor models, thus providing an efficient approach for combating metastatic tumors.

Keywords: Anti-metastasis; CXCR4 antagonist; Cell adhesion molecules; Migration chain; miR-34a.