Expression of CD24 is associated with HER2 expression and supports HER2-Akt signaling in HER2-positive breast cancer cells.
Bottom Line: However, resistance to HER2-targeted therapy remains a major clinical problem.HER2-positive breast tumors are predominantly positive for CD24, suggesting that the expression of the two molecules is related.Flow cytometry thus revealed that the percentage of CD24-positive cells was markedly higher in the HER2-positive fraction than in the HER2-negative fraction.
Affiliation: Division of Gene Regulation, Institute for Advanced Medical Research, School of Medicine, Keio University, Tokyo, Japan; Department of Breast Oncology, Tokyo Medical University, Tokyo, Japan.Show MeSH
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Mentions: We examined whether CD24 might affect HER2 expression with the use of RNA interference in the HER2-positive cell line BT-474. The abundance of CD24 and HER2 mRNA was significantly reduced by transfection of the cells with corresponding targeted siRNA (Fig. 5a). Flow cytometry analysis revealed that the percentage of CD24-expressing cells was also markedly reduced by knockdown of CD24 (from 98.9% for cells transfected with a control siRNA to 56.2%). The HER2-negative faction was increased by transfection with the CD24 siRNA (from 71.3% to 59.8%) (Fig. 5b). In contrast, knockdown of HER2 did not affect the proportion of cells expressing CD24 (98.9% for the control siRNA versus 98.1% for the HER2 siRNA) (Fig. 5c). These results imply that CD24 plays a role in maintenance of HER2-positive cells.
Affiliation: Division of Gene Regulation, Institute for Advanced Medical Research, School of Medicine, Keio University, Tokyo, Japan; Department of Breast Oncology, Tokyo Medical University, Tokyo, Japan.