To elucidate the mechanisms by which the mir-200 and the miR-183~96~182 cluster could regulate EMT and thus cellular migration, invasion and metastasis in NSCLC, we searched for common predicted targets of these microRNA families that might have a potential role in these biological processes. First we performed a cross comparison of multiple gene expression datasets from our mouse models of metastasis. We overlapped 224 genes that were elevated greater than four-folds upon Zeb1 induction in 393P cells with 210 genes that showed greater than two-fold increase in expression in the metastatic 344SQ cells compared to the non-metastatic 393P cells and 143 genes that were repressed to less than 0.5-fold in cells with exogenous expression of miR-200. This resulted in an enriched list of 45 genes that are potential miR-200 targets having a role in the process of EMT and metastasis. Next we performed an overlap of genes that were predicted targets of the miR-200 family members and the miR-183~96~182 cluster using the microRNA prediction algorithms miRanda (www.microRNA.org) and identified a list of 17 highly conserved common targets with a mirSVR score less than -6.0. The only 2 genes common in both the overlapping subsets were Zeb1 and Foxf2.
The miR-200 family and the miR-183~96~182 cluster target Foxf2 to inhibit invasion and metastasis in lung cancers.
Cell line, Treatment
View SamplesAnalysis of gene expression in lungs of C57BL/6J mice that develop chronic airway disease phenotypes after a single Sendai virus infection, compared with mice treated with UV-inactivated virus.
Persistent activation of an innate immune response translates respiratory viral infection into chronic lung disease.
Sex, Time
View SamplesBRCA1, a well-known breast and ovarian cancer susceptibility gene with multiple interacting partners, is predicted to have diverse biological functions. However, to date its only well-established role is in the repair of damaged DNA and cell cycle regulation. In this regard, the etiopathological study of low penetrant variants of BRCA1 provides an opportunity to uncover its other physiologically important functions. Using this rationale, we studied the R1699Q variant of BRCA1, a potentially moderate risk variant, and found that it does not impair DNA damage repair but abrogates the repression of miR-155, a bona fide oncomir. We further show that in the absence of functional BRCA1, miR-155 is up-regulated in BRCA1-deficient mouse mammary epithelial cells, human and mouse BRCA1-deficienct breast tumor cell lines as well as tumors. Mechanistically, we found that BRCA1 represses miR-155 expression via its association with HDAC2, which deacetylates H2A and H3 on the miR-155 promoter. Finally, we show that over-expression of miR-155 accelerates whereas the knockdown of miR-155 attenuates the growth of tumor cell lines in vivo. Taken together, our findings demonstrate a new mode of tumor suppression by BRCA1 and reveal miR-155 as a potential therapeutic target for BRCA1-deficient tumors.
Tumor suppressor BRCA1 epigenetically controls oncogenic microRNA-155.
Specimen part
View SamplesWe examined the functional significance of the R1699Q variant of human BRCA1 gene using a mouse ES cell-based assay.
Tumor suppressor BRCA1 epigenetically controls oncogenic microRNA-155.
Specimen part
View Samples