[MicroRNA-205 targeted Krüppel-like factor 12 and regulated MDA-MB-468 cells apoptosis in basal-like breast carcinoma].

OBJECTIVE

To identify basal-like breast carcinoma (BLBC)-specific microRNA (miRs) and its target gene and to investigate the distinct biological function.

METHOD

Krüppel-like factor 12 (KLF12) 3'-UTR was constructed and luciferase reporter assay was performed for target gene. Expression levels of miR including its target genes were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR), Western blot and immunohistochemistry (IHC). Further functional analyses were conducted which included apoptosis.

RESULTS

Luciferase assay showed miR-205 directly targets KLF12 through binding its 3'-UTR (P=0.001 6). QRT-PCR revealed that miR-205 expression levels were exclusively lower in MDA-MB-468 cell lines (P=0.00 7) and BLBC tumor tissues (P=0.007 4; n=3), but KLF12 were highly expressed in MDA-MB-468 cell lines (P=0.003 9); knock-up of miR-205 expression by transfection with its mimics in MDA-MB-468 cells substantially increased miR-205 expression level (P=0.000) and reduced KLF12 expression level (P=0.038). Western blot displayed that KLF12 expression levels were higher in tumor tissues when compared with normal breast tissues (P=0.008 3; n=9). Knock-up of miR-205 expression by transfection with its mimics promoted MDA-MB-468 cells apoptosis (P=0.006 1).

CONCLUSIONS

Our results suggest that miR-205 is a miR specific for BLBC which exerts tumor suppression role through negative regulated proto-oncogene KLF12 and promote cell apoptosis. MiR-205 and KLF12 may provide potential diagnosis molecular biomarker and possible new approach for the treatment for BLBC.