49P - MiR-155 promotes breast cancer progression by upregulating cancer stemness

Background

To date, miR-155 is known as an oncogenic miRNA with a well-documented role in breast cancer. Cancer stemness plays an important role in various aspects of carcinogenesis. The aim of this study is to investigate the effect of miR-155 on breast cancer proliferation by upregulating cancer stem cells.

Methods

In vivo-tumor growth and metastasis were measured across polyomavirus middle T antigen (PyVmT) transgenic mice and PyVmT miR-155 knockout mice. Western blot and quantitative real-time polymerase chain reaction (qRT-PCR) were employed to determine the protein and mRNA levels, respectively. The cancer stemness was assessed by sphere formation as well as the expression of the related markers. The miR-155 target genes were predicted and analyzed by western blot and luciferase assay.

Results

Upregulation of miR-155 in breast cancer tissues of mice identified poor prognosis and cancer metastasis. Upregulation of miR-155 was also found in breast cancer stem cells. Ectopic expression of miR-155 promotes the stemness of breast cancer cells. Conversely, depletion of miR-155 attenuates the stemness of these cells. miR-155 directly binds to CYLD and Sharp-1 to influence breast cancer stemness.

Conclusions

MicroRNA-155 promotes breast cancer progression by upregulating breast cancer stemness.

Editorial acknowledgement

Clinical trial identification

Legal entity responsible for the study

The author.

Funding

Has not received any funding.

Disclosure

The author has declared no conflicts of interest.