Conclusions
Our study gets an insight into the transcriptomic features of invasive breast stroma and transcription regulatory mechanisms for stroma cell transformation, providing a proof-of-concept of stroma-targeting strategy in cancer treatment.
Methods
We conducted transcriptomic analyses in paired NFs and CAFs isolated from clinical specimens of breast cancer patients with metastasis. Meanwhile, genome-wide mapping of histone marks H3K4me1 and H3K27ac was also performed to characterize CAF-specific enhancer landscape. The function and mechanisms of activated JUN in stromal fibroblasts were studied using in vitro and in vivo models.
Results
We have identified CAF-specific signature genes and activated enhancers, which are significantly associated with pro-metastatic programs. Among the CAF activated enhancers, FOS and JUN family of transcription factors are enriched. In line with this, we find that JUN protein is highly activated in the stroma of metastatic breast cancers. And through gain and loss-of-function studies, we demonstrate that activated JUN is necessary and sufficient to remodel enhancers and maintain the activation of CAF-specific enhancers, and thereby promotes breast cancer invasiveness in a non-cell-autonomous manner. Conclusions: Our study gets an insight into the transcriptomic features of invasive breast stroma and transcription regulatory mechanisms for stroma cell transformation, providing a proof-of-concept of stroma-targeting strategy in cancer treatment.