Abstract
Dysregulated microRNAs play important pathological roles in carcinogenesis that are yet to be fully elucidated. This study was performed to investigate the biological functions of microRNA-320a (miR-320a) in breast cancer and the underlying mechanisms. Function analyses for cell proliferation, cell cycle, and cell invasion/migration, were conducted after miR-320a silencing and overexpression. The specific target genes of miR-320a were predicted by TargetScan algorithm and then determined by dual luciferase reporter assay and rescue experiment. The relationship between miR-320a and its target genes was explored in human breast cancer tissues. We found that miR-320a overexpression could inhibit breast cancer invasion and migration abilities in vitro, while miR-320a silencing could enhance that. In addition, miR-320a could suppress activity of 3′-untranslated region luciferase of metadherin (MTDH), a potent oncogene. The rescue experiment revealed that MTDH was a functional target of miR-320a. Moreover, we found that MTDH was negatively correlated with miR-320a expression, and it was related to clinical outcomes of breast cancer. Further xenograft experiment also showed that miR-320a could inhibit breast cancer metastasis in vivo. Our findings clearly demonstrate that miR-320a suppresses breast cancer metastasis by directly inhibiting MTDH expression. The present study provides a new insight into anti-oncogenic roles of miR-320a and suggests that miR-320a/MTDH pathway is a putative therapeutic target in breast cancer.
Highlights
MiR-320a is not involved in cell proliferation and cell cycle in breast cancer
T-47D cells with moderately higher expression of miR-320a were transfected with anti-miR-320a of anti-NC
Transfection with pre-miR320a or anti-mir-320a led to significant increase or decrease in miR-320a expression when compared to their cognate NC as described before (Figure 2A)
Summary
MiR-320a expression was determined by qRT-PCR using TaqMan miRNA Assay (Invitrogen), with RNU6B as an internal control. Target mRNA expression was determined by qRT-PCR with SYBR® Premix Ex TaqTM (Takara Bio, Dalian, China) with GAPDH as an internal reference. The primer sequences are listed in Supplementary Table S1. Relative expression level was calculated by the 2−ΔΔCT method [ΔCt = Ct (miR-320a) – Ct (GAPDH/RNU6B), ΔΔCt = ΔCt (cancer)- ΔCt (normal)], where Ct value represented the threshold cycle for each transcript.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
