miR-200b as a prognostic factor in breast cancer targets multiple members of RAB family.
BACKGROUND
miR-200b has been reported to be a tumor suppressor and a promising therapeutic target in cancer. miR-200b has been associated with epithelial-mesenchymal transition and chemo-resistance in cancer. The aim of this study is to investigate the expression of miR-200b, its prognostic roles and its potential targets in breast cancer.


METHODS
qRT-PCR was used to detect miR-200b expression in breast cancer tissues and cell lines. In situ hybridization of miR-200b on tissue microarray including 134 breast cancer samples was used to evaluate its prognostic role. Novel targets of miR-200b in breast cancer were predicted and confirmed by luciferase reporter assay and western bloting. Immunohistochemical staining was used for protein detection. The biological effects of miR-200b in breast cancer cells were further confirmed by ectopic expression of its mimics followed by MTT assay and invasion test.


RESULTS
miR-200b was downregulated in breast cancer tissues and cell lines and its low-expression correlated with poor outcome in breast cancer patients. Members of RAB family, RAB21, RAB23, RAB18 and RAB3B were predicted to be the targets of miR-200b. The luciferase reporter assay was performed to certificate this prediction. The expressions of RAB21, RAB23, RAB18 and RAB3B were suppressed by transfection of miR-200b in breast cancer cells. Over-expression of miR-200b or knock-down of RAB21, RAB23, RAB18 and RAB3B inhibited breast cancer cell proliferation and invasion in vitro.


CONCLUSIONS
Our study provides evidence that miR-200b is a prognostic factor in breast cancer targeting multiple members of RAB family. MiR-200b could be a potential therapeutic target in breast cancer.
Feng
F
Ye
Hailin
H
Tang
Qing
Q
Liu
Xinhua
X
Xie
Minqing
M
Wu
Xiaoping
X
Liu
Bo
B
Chen
Department of Breast Oncology, Sun Yat-Sen University Cancer Center, 651 East Dongfeng Road, Guangzhou, Guangdong 510060, People's Republic of China. xiexm@sysucc.org.cn.
Xiaoming
X
Xie
D001483:Base Sequence; D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D015536:Down-Regulation / Q000235:genetics; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D055785:Gene Knockdown Techniques; D006801:Humans; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D008875:Middle Aged; D008969:Molecular Sequence Data; D009361:Neoplasm Invasiveness; D011379:Prognosis; D020691:rab GTP-Binding Proteins / Q000378:metabolism*
C533896:MIRN200 microRNA, human; D035683:MicroRNAs; D020691:rab GTP-Binding Proteins