To explore changes of invasion capability of cancer stem cells loading miR30a derived from enlarging and proliferative axillary lymph node of patients with breast cancer in nude mice.

MiR30a oligonucleotide fragment loaded by adenovirus vector was transfected into breast cancer stem cells isolated from enlarging and proliferative axillary lymphnodes of patients with breast cancer, MDA-MB-231 cell lines as the control. The cancer cells were injected into axillary subcutaneous fat of the nude mice for several weeks, and then, the expression of Vimentin or N-Cadherin in tumor tissues of each group of the mice was determined by immunohistochemistry and western blot.

The average transfection rate of cancer stem cells loaded by miR30a was 62.5%, while it was 78.2% for MDA-MB-231. The tumor volume was larger in adenovirus vector groups or in control groups of nude mice than in experimental groups induced by mir30a. Vimentin or N-cadherin in tumor tissues was significantly downexpressed in experimental groups with mir30a ( (13.1±1.7) %, (15.3%±2.1) %) compared with that in adenovirus vector groups or in control groups ( (21.1±1.4) %, (25.3±1.6) %, P<0.05) , respectively. The difference between adenovirus vector groups and in control groups had no significant difference (P>0.05) . After inoculated for 6 weeks, except the subcutaneous plantations, no distant metastasis in nude mice was found. MDA-MB-231 cell lines groups had similar results.

The proliferative and invasive capability of cancer stem cells can be inhibited by miR30a, suggesting a new therapy for breast cancer.

Breast cancer stem cells; Nude mice; Proliferative inhibition; miRNA30a