Adipose Secreted Slit2-C Suppresses Breast Cancer Invasion Through cAMP/PKA Transition

Adipose tissue activation plays a positive role in breast cancer outcomes, consistent with the improved outcomes observed through exercise and weight loss mediated by brown and beige fat. However, the underlying mechanism of this process remains unclear. C-terminal fragment of Slit2 (Slit2-C), endogenously produced by brown or beige adipose cells could increase the thermogenic process of adipose cells in autocrine and paracrine manners. Here, we show that Slit2-C dominantly reduces breast cancer cell invasion through cAMP/PKA mediated inhibition of epithelial-mesenchymal transition. In the process, Slit2-C plays a vital role as a positive regulator of cAMP/PKA signaling in breast cancer. As a result, the overexpression of Slit2-C leads to a reduction in cancer cell invasion and an increase in both the epithelial phenotype and thermogenesis. Besides, inhibiting PKA phosphorylation with H89 reversed the reduced invasion process seen in human breast cancer cells overexpressing Slit2-C, which suggests that the effect of Slit2-C on reducing invasion is mediated through the activation of PKA signaling. Taken together, our study suggests that the modulation of the Slit2-C/cAMP/PKA axis might be a potential targeting therapeutic intervention in aggressive breast cancers.