Abstract
A productive immune response requires transient upregulation of the microRNA miR-155 in hematopoietic cells mediating innate and adaptive immunity. In order to investigate miR-155 in the context of tumor-associated immune responses, we stably knocked down (KD) miR-155 in the myeloid compartment of MMTV-PyMT mice, a mouse model of spontaneous breast carcinogenesis that closely mimics tumor-host interactions seen in humans. Notably, miR-155/KD significantly accelerated tumor growth by impairing classic activation of tumor-associated macrophages (TAMs). This created an imbalance toward a protumoral microenvironment as evidenced by a lower proportion of CD11c+ TAMs, reduced expression of activation markers, and the skewing of immune cells within the tumor toward an macrophage type 2/T helper 2 response. This study highlights the importance of tumor-infiltrating hematopoietic cells in constraining carcinogenesis and establishes an antitumoral function of a prototypical oncomiR.
Original language | English (US) |
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Pages (from-to) | 243-252 |
Number of pages | 10 |
Journal | Blood |
Volume | 122 |
Issue number | 2 |
DOIs | |
State | Published - 2013 |
Externally published | Yes |
ASJC Scopus subject areas
- Biochemistry
- Immunology
- Hematology
- Cell Biology