Abstract: Objective To investigate whether miR-210 played a crucial role in the process of inducing the transformation from co-cultured adipose derived(AD)-MSCs into CAFs. Methods Co-cultured adipose derived (AD)-MSCs with breast cancer cells (BCCs) lines in vitro and detected the expression of miR-210 using RT-qPCR. The expression of CAFs characteristic markers including α-SMA and tenascin-c were measured by RT-qPCR and the expression of α-SMA and FAPA were assessed by Western blot. Co-injected MCF-7 cells transfected with miR-210 inhibitor or miR-NC with MSC at 1: 1 ratio into the immunodeficient nude mice subcutaneously and observed tumor growth in vivo constantly. Results miR-210 were all up-regulated when a variety of breast cancer cells were co-cultured with MSCs (P<0.05). Inhibition of miR-210 in tumor cell could inhibit the transformation from MSCs into CAFs (P<0.05). Animal experiments further confirmed that inhibition of miR-210 in tumor cell could reduce tumor growth (P<0.05). Conclusion As an important information molecule, miR-210 mediates the transformation from MSCs to CAFs in the tumor microenvironment.

Key words: miR-210, mesenchymal stem cells , cancer-associated fibroblasts , breast cancer cells