| Summa ry
Purpose: The microRNA (miR)-31 and miR-143 are pleiotropic
anti-metastatic miRs, with an expression that decreases
significantly in metastatic breast cancer cells. The
aim of this study was to investigate the effect of miR-31
and miR-143 inhibition on metastasis and invasion in both
MDA-MB231, MDA-MB468 as well as the MCF-7 breast
cancer cell lines and 5-week old female mice.
Methods: Following the cloning of miR-31 and miR-143
into vectors, their expressions were determined before treatment
with constructs of miR-31 and miR-143 in cancer cell
lines and normal breast cells. Then miR-31 and miR-143
were transfected to the cell lines and the expression was assessed
after 48 hrs. Moreover, the levels of migration and
invasion were determined in cell lines. These experiments
were performed in 5-week old female mice.
Results: The results showed that miR-31 expression before
the transfection of miR-31 construct was decreased 4, 70 and
100 times in MCF-7, MDA-MB468 and MDA-MB231 cell
lines, respectively, in comparison to normal breast cells; but
after the transfection of miR-31 construct, the expression
of miR-31 increased 80 times. Additionally, invasion and
migration decreased by 15 and 10 times in MDAMB-468.
All of the modifications in miR-143 were low in comparison
to miR-31. The results of the in vivo experiments were approximately
the same as in the in vitro experiments.
Conclusions: IIt appears that the use of miR-31 is highly
efficient than miR-143 in the inhibition of invasion and metastasis
in breast cancer. Our study improved our conception
about miR-31 and miR-143 and their roles in the identification
and therapy of breast cancer. |