Loss of oncogenic miR-155 in tumor cells promotes tumor growth by enhancing C/EBP-β-mediated MDSC infiltration.

ABSTRACT: The oncogenic role of microRNA-155 (miR-155) in leukemia is well established but its role in other cancers, especially breast cancer, is gradually emerging. In this study we examined the effect of mir-155 loss in a well-characterized spontaneous breast cancer mouse model where Brca1 and Trp53 are deleted by K14-Cre. miR-155 is known to be up-regulated in BRCA1-deficient tumors. Surprisingly, complete loss of miR-155 (miR-155ko/ko) did not alter the tumor free survival of the mutant mice. However, we found increased infiltration of myeloid derived suppressor cells (MDSCs) in miR-155 deficient tumors. In addition, cytokine/chemokine array analysis revealed altered level of cytokines that are implicated in the recruitment of MDSCs. Mechanistically, we identified C/EBP-β, a known miR-155 targe

SUBMITTER: Kim S 

PROVIDER: S-EPMC4905460 | biostudies-literature | 2016 Mar

REPOSITORIES: biostudies-literature