Abstract
Carcinoma associated fibroblasts (CAFs) play important roles in breast cancer development and progression. Recent studies show that microRNAs (miRNAs) are the main regulators in CAFs. MiR-29b is one of the significant down-regulated miRNAs in CAFs from the miRNA screening. The role of miR-29b in the interaction between CAFs and breast cancer is still unclear. In the present study, we investigated the effects of CAFs on breast cancer cell proliferation and metastasis regulated by miR-29b. We found that fibroblasts activated by co-cultured breast cancer cells produced higher levels of some chemokines like CCL11, CXCL14, which accelerated breast cancer cell growth and induced drug resistance and metastasis. Increased miR-29b expression in activated fibroblasts could suppress the activating p38-STAT1 signal pathway in breast cancer cells. We also found that the expression of CCL11 and CXCL14 could be regulated by miR-29b in CAFs. Our results illustrate that down-regulation of miR-29b in CAFs plays an important role in tumor stroma by activating p38-STAT1 in breast cancer cells. The study indicates that cancer cells and fibroblasts interaction promotes breast cancer cell growth, drug resistance, migration and invasion due to the lack of miR-29b expression in CAFs.
Highlights
The tumor microenvironment plays very important roles in the development and progression of cancer
The results indicated that cancer-associated fibroblasts (CAFs) were different from normal fibroblasts (NFs), and CAFs showed the features of the activated fibroblasts
It was found that miR-29b including miR-29b-1-5p and miR-29b-2-5p were down-regulated in CAFs compared to NFs (Figure 1F–1G)
Summary
The tumor microenvironment plays very important roles in the development and progression of cancer. Cancer tissues consist of various cells include cancer cells, fibroblasts, endothelial cells, pericytes, immune cells and various bone marrow-derived progenitor cells [1,2]. Fibroblasts are the most enriched cells in tumor stroma. The activated cancer-associated fibroblasts (CAFs) in the cancer niche build a permissive and supportive microenvironment for tumor development. Fibroblasts play important roles in cancer progression including metabolism, metastasis, proliferation, anti-apoptosis, angiogenesis and chemo-resistance by interaction with cancer cells or other cells [3,4,5]. Fibroblasts could affect behaviors of cancer cells by activating signal pathways, microRNAs (miRNAs), and soluble molecules and so on
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
