Establishment and Characterization of MTDH Knockdown by Artificial MicroRNA Interference - Functions as a Potential Tumor Suppressor in Breast Cancer

Background: Considerable evidence suggests that metadherin (MTDH) is a potentially crucial mediator oftumor malignancy and an important therapeutic target for simultaneously enhancing chemotherapy efficacyand reducing metastasis risk. Inhibition of MTDH expression by RNA interference has been shown in severalprevious research, but silencing MTDH expression by microRNA (miRNA) interference in breast cancer hasnot been established. In the present study, we investigated the role of MTDH-miRNA in down-regulation ofproliferation, motility and migration of breast carcinoma cells.
Methods: Expression vectors of recombinantplasmids expressing artificial MTDH miRNA were constructed and transfected to knockdown MTDH expressionin MDA-MB-231 breast cancer cells. Expression of MTDH mRNA and protein was detected by RT-PCR andWestern blot, respectively. MTT assays were conducted to determine proliferation, and wound healing assaysand transwell migration experiments for cell motility and migration.
Results: Transfection of recombinant aplasmid of pcDNA-MTDH-miR-4 significantly suppressed the MTDH mRNA and protein levels more than69% in MDA-MB-231 breast cancer cells. This Knockdown significantly inhibited proliferation, mothlity andmigration as compared with controls.
Conclusions: MTDH-miRNA may play an important role in downregulatingproliferation, motility and migration in breast cancer cells, and should be considered as a potentialsmall molecule inhibitor therapeutic targeting strategy for the future.