PDF file - 131K, Supplementary Figure S1. Luciferase reporter assay and expression levels of miR-23b and miR-27b and their putative targets. Supplementary Figure S2. Antisense miR-23b and miR-27b inhibited cell invasion. Supplementary Figure S3. The expression of miR-23b/27b and Nischarin in knockdown cells. Supplementary Figure S4. MEK1 inhibitor (U0126) did not affect expression of miR-23b/27b in SKBR3 cells. Supplementary Figure S5. EGF and TNF enhanced miR-23b and miR-27b expression in MDA-MB-231 cells.
ARTICLE ABSTRACT
miRNAs (miR) are a critical class of small (21–25 nucleotides) noncoding endogenous RNAs implicated in gene expression regulation. We identified miR-23b and miR-27b as miRNAs that are highly upregulated in human breast cancer. We found that engineered knockdown of miR-23b and miR-27b substantially repressed breast cancer growth. Nischarin (NISCH) expression was augmented by knockdown of miR-23b as well as miR-27b. Notably, these miRNAs and Nischarin were inversely expressed in human breast cancers, underscoring their biologic relevance. We showed the clinical relevance of the expression of these miRNAs and showed that high expression of miR-23b and miR-27b correlates with poor outcome in breast cancer. Moreover, intraperitoneally delivered anti-miR-27b restored Nischarin expression and decreased tumor burden in a mouse xenograft model of human mammary tumor. Also, we report for the first time that HER2/neu (ERBB2), EGF, and TNF-α promote miR-23b/27b expression through the AKT/NF-κB signaling cascade. Nischarin was found to regulate miR-27b/23b expression through a feedback loop mechanism by suppressing NF-κB phosphorylation. Because anti-miR-27b compounds that suppress miR-27b inhibit tumor growth, the anti-miR-27b seems to be a good candidate for the development of new antitumor therapies. Cancer Res; 73(9); 2884–96. ©2013 AACR.
