MicroRNA-335 inhibits breast cancer cell invasion by targeting human epidermal growth factor receptor 3

Abstract

Objective In this study, we aim to detect microRNA(miR)- 335 function in cell invasion. Methods In vitro, we respectively inhibited or over- expressed miR- 335 in MCF10A and MCF7 to detect the change of cell invasion by transwell invasion assay.The bioinformatics was used to predict the target of miR- 335 and later it was investigated by luciferase reporter assay.Through the single- tranfection or cotransfection of miR- 335 inhibitor or human epidermal growth factor receptor 3(ERBB3)siRNA, we detected whether miR- 335 affects invasion by targeting ERBB3.At last, through realtime quantative polymerase chain reaction, we detected the expression level of miR- 335 in primary breast cancer specimen. Results Inhibition of miR- 335 in MCF10A reduced the ability of cell invasion.Invasion cell numbers enhanced from 51 of control group to 67 of exprimental group.The P value is lower than 0.05.Over- expression of miR- 335 enhanced the ability of cell invasion.Invasion cell numbers decreased from 51 of control group to 43 of exprimental group(P<0.05).miR- 335 could target the 3'untranslated regions of ERBB3 mRNA and inhibited its mRNA and protein level(P<0.05).Inhibition of ERBB3 could resuce the change of cell invasion that miR-335 inhibitors contributed to(P< 0.05).miR- 335 showed lower expression level in primary breast cancer specimen compared to adjacent tissues(P<0.01). Conclusion miR-335 showed lower expression in primary breast cancer and affected breast cancer cell invasion by targeting ERBB3. Key words: Breast cancer; MicroRNA-335; Human epidermal growth factor receptor 3; Invasion