MiR-155-3p acts as a tumor suppressor and reverses paclitaxel resistance via negative regulation of MYD88 in human breast cancer.

MiR-155-3p, which is derived from the same pre-miRNA as miR-155-5p, the latter has been reported to be dysregulated in multiple tumor tissues and associated with clinicopathologic markers, tumor subtypes, and poor survival rates. However, the biological effects of miR-155-3p are rarely explored. In this study, we find that miR-155-3p was down-regulated in breast cancer and MYD88 was validated as the target for miR-155-3p. Moreover, miR-155-3p showed a negative effect on apoptosis, invasion and metastasis, reverses paclitaxel resistance by suppression of the corresponding target gene MYD88 in vitro and in vivo experiments. Taking together, our studies suggest that miR-155-3p, which serve as a negative regulatory mechanism for breast cancer development. The mechanism further complicates the regulatory network in human breast cancer.