The inhibitory role of Mir-29 in growth of breast cancer cells

Mir-29 microrna families are involved in regulation of various types of cancers. although mir-29 was shown to play an inhibitory role in tumorigenesis,the role of mir-29 in breast cancer still remains obscure. in this study,we showed that mir-29a is the dominant isoform in its family in mammary cells and expression of mir-29a was down-regulated in different types of breast cancers. furthermore,over-expression of mir-29a resulted in significant slower growth of breast cancer cells and caused higher percentage of cells at g0/g1 phase. consistent with this over-expression data,knockdown of mir-29a in normal mammary cells lead to higher cell growth rate,and higher percentage of cells entering s phase. we further found that mir-29a negatively regulated expression of b-myb,which is a transcription factor associated with tumorigenesis. the protein levels of cyclin a2 and d1 are consistent with the protein level of b-myb. taken together,our data suggests mir-29a plays an important role in inhibiting growth of breast cancer cells and arresting cells at g0/g1 phase. our data also suggests that mir-29a may suppress tumor growth through down-regulating b-myb. © 2013 wu et al.; licensee biomed central ltd.