MicroRNA-145 promotes esophageal cancer cells proliferation and metastasis by targeting SMAD5.

OBJECTIVE

To clarify the relative expression and molecular function of microRNA (miR)-145 in esophageal cancer and understand its mechanistic involvement in this disease.

MATERIAL AND METHODS

The relative expression of miR-145 in clinical samples was analyzed using the public GSE43732 dataset. The prognostic analysis with respect to miR-145 expression was performed with Kaplan-Meier plot. Cell viability was measured by MTT assay and the anchorage-independent growth was evaluated by soft agar assay. The migration and invasion of esophageal cancer cells were measured using transwell chamber. The regulatory effect of miR-145 on SMAD5 was determined by dual-luciferase reporter assay. The endogenous SMAD5 protein was measured by Western blot.

RESULTS

We demonstrated high expression of miR-145 associated with late stage and unfavorable prognosis of esophageal cancer. Ectopic expression of miR-145 mimic significantly stimulated cell proliferation and anchorage-independent growth. Furthermore, high level of miR-145 significantly promoted both migration and invasion in vitro. Notably, we identified SMAD5 as direct target of miR-145, the suppressed expression of which consequently led to increased cell proliferation and migration/invasion.

CONCLUSION

Our study uncovered the crucial role of miR-145/SMAD5 in esophageal cancer and highlighted its target potential for diagnostic and therapeutic purpose.