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miR‐10b expression in breast cancer stem cells supports self‐renewal through negative PTEN regulation and sustained AKT activation
Author(s) -
BahenaOcampo Ivan,
Espinosa Magali,
CeballosCancino Gisela,
Lizarraga Floria,
CamposArroyo Denise,
Schwarz Angela,
Maldonado Vilma,
MelendezZajgla Jorge
Publication year - 2016
Publication title -
embo reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.584
H-Index - 184
eISSN - 1469-3178
pISSN - 1469-221X
DOI - 10.15252/embr.201540678
Subject(s) - pten , tensin , protein kinase b , cancer research , microrna , gene knockdown , pi3k/akt/mtor pathway , cancer stem cell , biology , metastasis , stem cell , competing endogenous rna , microbiology and biotechnology , cell culture , cancer , signal transduction , rna , gene , long non coding rna , genetics
Cancer stem cells ( CSC s) are linked to metastasis. Moreover, a discrete group of mi RNA s (metastamiRs) has been shown to promote metastasis. Accordingly, we propose that mi RNA s that function as metastatic promoters may influence the CSC phenotype. To study this issue, we compared the expression of 353 mi RNA s in CSC s enriched from breast cancer cell lines using qRT – PCR analysis. One of the most altered mi RNA s was miR‐10b, which is a reported promoter of metastasis and migration. Stable overexpression of miR‐10b in MCF ‐7 cells (miR‐10b‐OE cells) promoted higher self‐renewal and expression of stemness and epithelial–mesenchymal transition ( EMT ) markers. In agreement with these results, inhibiting miR‐10b expression using synthetic antisense RNA s resulted in a decrease in CSC s self‐renewal. Bioinformatics analyses identified several potential miR‐10b mRNA targets, including phosphatase and tensin homolog ( PTEN ), a key regulator of the PI 3K/ AKT pathway involved in metastasis, cell survival, and self‐renewal. The targeting of PTEN by miR‐10b was confirmed using a luciferase reporter, qRT – PCR , and Western blot analyses. Lower PTEN levels were observed in CSC s, and miR‐10b depletion not only increased PTEN mRNA and protein expression but also decreased the activity of AKT , a downstream PTEN target kinase. Correspondingly, PTEN knockdown increased stem cell markers, whereas AKT inhibitors compromised the self‐renewal ability of CSC s and breast cancer cell lines overexpressing miR‐10b. In conclusion, miR‐10b regulates the self‐renewal of the breast CSC phenotype by inhibiting PTEN and maintaining AKT pathway activation.