Metadherin Regulates Inflammatory Breast Cancer Invasion and Metastasis

Inflammatory breast cancer (IBC) is one of the most lethal subtypes of breast cancer (BC), accounting for approximately 1-5% of all cases of BC. Challenges in IBC include accurate and early diagnosis and the development of effective targeted therapies. Our previous studies identified the overexpression of metadherin (MTDH) in the plasma membrane of IBC cells, further confirmed in patient tissues. MTDH has been found to play a role in signaling pathways related to cancer. However, its mechanism of action in the progression of IBC remains unknown. To evaluate the function of MTDH, SUM-149 and SUM-190 IBC cells were edited with CRISPR/Cas9 vectors for in vitro characterization studies and used in mouse IBC xenografts. Our results demonstrate that the absence of MTDH significantly reduces IBC cell migration, proliferation, tumor spheroid formation, and the expression of NF-kappa B and STAT3 signaling molecules, which are crucial oncogenic pathways in IBC. Furthermore, IBC xenografts showed significant differences in tumor growth patterns, and lung tissue revealed epithelial-like cells in 43% of wild-type (WT) compared to 29% of CRISPR xenografts. Our study emphasizes the role of MTDH as a potential therapeutic target for the progression of IBC.

Automated summary

Inflammatory breast cancer (IBC) is a lethal subtype of breast cancer, comprising 1-5% of all cases. This study confirms the overexpression of metadherin (MTDH) in IBC cells and reveals its crucial role in IBC progression, including signaling pathway regulation and tumor growth promotion. CRISPR/Cas9 editing of IBC cells shows that the absence of MTDH significantly reduces cell migration, proliferation, and tumor spheroid formation, as well as the expression of key signaling molecules in IBC. Additionally, IBC xenografts exhibit distinct tumor growth patterns and phenotypes in lung tissue. These findings highlight MTDH as a potential therapeutic target for IBC.