miR-10b expression in breast cancer stem cells supports self-renewal through negative PTEN regulation and sustained AKT activation.
Cancer stem cells (CSCs) are linked to metastasis. Moreover, a discrete group of miRNAs (metastamiRs) has been shown to promote metastasis. Accordingly, we propose that miRNAs that function as metastatic promoters may influence the CSC phenotype. To study this issue, we compared the expression of 353 miRNAs in CSCs enriched from breast cancer cell lines using qRT-PCR analysis. One of the most altered miRNAs 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 RNAs resulted in a decrease in CSCs self-renewal. Bioinformatics analyses identified several potential miR-10b mRNA targets, including phosphatase and tensin homolog (PTEN), a key regulator of the PI3K/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 CSCs, 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 CSCs 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.
Basic Research Subdivision, National Institute of Genomic Medicine, Functional Genomics Laboratory, Mexico City, Mexico.
Ivan
I
Bahena-Ocampo
Basic Research Subdivision, National Institute of Genomic Medicine, Functional Genomics Laboratory, Mexico City, Mexico.
Magali
M
Espinosa
Basic Research Subdivision, National Institute of Genomic Medicine, Functional Genomics Laboratory, Mexico City, Mexico.
Gisela
G
Ceballos-Cancino
Basic Research Subdivision, National Institute of Genomic Medicine, Functional Genomics Laboratory, Mexico City, Mexico.
Floria
F
Lizarraga
Basic Research Subdivision, National Institute of Genomic Medicine, Functional Genomics Laboratory, Mexico City, Mexico.
Denise
D
Campos-Arroyo
Basic Research Subdivision, National Institute of Genomic Medicine, Functional Genomics Laboratory, Mexico City, Mexico.
Angela
A
Schwarz
Basic Research Subdivision, National Institute of Genomic Medicine, Functional Genomics Laboratory, Mexico City, Mexico.
Vilma
V
Maldonado
Basic Research Subdivision, National Institute of Genomic Medicine, Functional Genomics Laboratory, Mexico City, Mexico jmelendez@inmegen.gob.mx.
Jorge
0000-0002-2209-1607
J
Melendez-Zajgla
Basic Research Subdivision, National Institute of Genomic Medicine, Functional Genomics Laboratory, Mexico City, Mexico jmelendez@inmegen.gob.mx.
Patricia
P
Garcia‐Lopez
D000818:Animals; D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism*; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000235:genetics; D000066673:Cell Self Renewal / Q000235:genetics*; D004195:Disease Models, Animal; D058750:Epithelial-Mesenchymal Transition / Q000235:genetics; D005260:Female; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D064593:Heterografts; D006801:Humans; D051379:Mice; D035683:MicroRNAs / Q000235:genetics*; D014411:Neoplastic Stem Cells / Q000378:metabolism*; D051059:PTEN Phosphohydrolase / Q000235:genetics* / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D015398:Signal Transduction; D059467:Transcriptome
C547183:MIRN10 microRNA, human; D035683:MicroRNAs; D012333:RNA, Messenger; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D051059:PTEN Phosphohydrolase
hsa‐miR‐10b; microRNAs; non‐coding RNAs; tumor‐initiating cancer cells