Taraxacum mongolicum Hand.-Mazz. extract disrupts the interaction between triple-negative breast cancer cells and tumor-associated macrophages by inhibiting RAC2/NF-κB p65/p38 MAPK pathway.

Ethnopharmacological Relevance: Taraxacum mongolicum Hand.-Mazz., generally known as dandelion, is a herb renowned for its pharmacological properties, including detoxifying and anti-inflammatory effects. Historically, this herb has been extensively utilized in the treatment of breast diseases. Recent studies have demonstrated that dandelion exhibits inhibitory properties against triple-negative breast cancer (TNBC) and modulates the tumor-associated macrophages (TAMs) microenvironment. However, the primary pharmacological mechanisms remain to be completely revealed.

Aim Of The Study: This study is focused on examining the mechanism by which dandelion extract regulates the communication between TNBC and TAMs through an integrative approach of network-based pharmacology and experimental verification.

Materials And Methods: A three-dimensional (3D) co-culture cell model was employed to visualize the impact of dandelion extract on the crosstalk between TAMs and TNBC. To shed light on the crucial mechanisms of dandelion inhibitory effects on TNBC, a network pharmacology analysis was undertaken. Transwell assays were utilized to assess cell capabilities to migrate and infiltrate. Small interfering RNA (siRNA) and an overexpression plasmid targeting Ras-related C3 botulinum toxin substrate 2 (RAC2) were applied to knock down or upregulate the expression levels of RAC2. The altered expression levels of associated molecules were evaluated using quantitative real-time PCR, Western blotting, and immunohistochemistry.

Results: The results from 3D co-culture model demonstrated that dandelion extract significantly hindered the consolidating strength between TNBC cells and TAMs. The extract effectively suppressed TAM-induced epithelial-mesenchymal transition (EMT) in TNBC cells and inhibited the recruitment of TAMs and M2 polarization mediated by TNBC cells. Network pharmacology analysis predicted that dandelion extract attenuates the inflammatory response in TNBC through NF-κB p65/p38 MAPK. Notably, dandelion extract reduced the levels of NF-κB p65/p38 MAPK-related cytokines, including TNF-α, IL-1β, and IL-6 in TNBC cells, while increasing them in TAMs. Overexpression of RAC2 in TNBC cells not only augmented their proliferation, migration, invasion, and EMT processes but also facilitated increased recruitment and M2 polarization of TAMs. TAMs were observed to promote lung metastasis, whereas dandelion extract significantly inhibited lung metastasis and EMT in 231 xenografts. Mechanically, dandelion extract significantly mitigated the RAC2/NF-κB p65/p38 MAPK-mediated inflammatory response both in TNBC cells and 231 xenografts, thereby disrupting the crosstalk between TNBC cells and TAMs.

Conclusion: Dandelion extract inhibits the crosstalk between TNBC and TAMs through RAC2/NF-κB p65/p38 MAPK inflammatory pathway, thereby suppressing lung metastasis in TNBC. This study revealed dandelion extract exerts a bidirectional regulatory effect on inflammation in modulating the interaction between TNBC and TAMs, offering a promising therapeutic insight for TNBC treatment.