Overexpression of miR -155 Promotes Proliferation and Invasion of Human Laryngeal Squamous Cell Carcinoma via Targeting SOCS1 and STAT3

MicroRNA155 plays an important role in many solid malignancies. Expression and function of miR-155 in laryngeal carcinoma have not been fully understood. This study aims to investigate the expression and function of miR-155 in laryngeal squamous cell carcinoma (LSCC), the relationship between miR-155 and its downstream target suppressor of cytokine signaling 1 (SOCS1)-STAT3 pathway, and the related clinicopathological factors. Sixty-three samples of laryngeal squamous cell carcinoma and twenty-one samples of control mucosa obtained from total laryngectomy cases were analyzed using Western blot analysis and real-time PCR. Hep-2 cells were cultured and transfected with miR-155 mimic and ASO. Cell proliferation, migration and invasion assays were used to determine the role of miR-155 in regulation of LSCC growth, migration, and invasion, respectively. The expression levels of miR-155 in LSCC were significantly higher than those in the control mucosa tissues. Downregulation of SOCS1 expression and elevated expression of STAT3 were also observed in LSCC. The relevance of the three factors were statistically significant. Moreover, knockdown of miR-155 elevated SOCS1expression level, suppressed STAT3 expression, and inhibited hep-2 cells growth, migration and invasion. Whereas overexpression of miR-155 inhibited SOCS1expression, elevated STAT3 expression, and promoted hep-2 cells growth, migration and invasion. Furthermore, the miR-155 levels in T(3) T(4) stages, and poor/moderate cell differentiation were significantly higher than those in T(2) stage and higher degree of cell differentiation. The STAT3 protein in poor/moderate cell differentiation was significantly higher than those in higher degree of cell differentiation. We firstly demonstrated the aberrant expression and function of miR-155 and itsdownstream targets in LSCC. The current findings suggest that miR-155 play promotingrole during the development of LSCC, and miR-155 may be a useful marker for the prognosis and assessment of therapeutic effects.