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: Finally, we examined whether knockdown of CD24 might increase the sensitivity of breast cancer cells to HER2-targeted therapy. Treatment of CD24-depleted or control BT-474 cells with lapatinib, a dual tyrosine kinase inhibitor for both the epidermal growth factor receptor and HER2, revealed that knockdown of CD24, indeed, enhanced the antiproliferative and death-promoting effects of lapatinib (Fig. 7a). We also found that HER2-90 cells are resistant to lapatinib (Fig. 7b), but that knockdown of CD24 increased the sensitivity of these cells to the antiproliferative and death-promoting effects of this agent (Fig. 7c). These data thus suggested that the expression of CD24 supports HER2-dependent cancer cell survival.
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.