YSA-conjugated mesoporous silica nanoparticles effectively target EphA2-overexpressing breast cancer cells

Neoadjuvant chemotherapy is commonly used to treat patients with locally advanced breast cancer and a common option for primary operable disease. However, systemic toxicity including cardiotoxicity and inefficient delivery are significant challenges form any chemotherapeutics. The development of targeted treatments that lower the risk of toxicity has, therefore, become an active area of research in the field of novel cancer therapeutics. Mesoporous silica nanoparticles (MSNs) have attracted significant attention as efficient drug delivery carriers, due to their high surface area and tailorable mesoporous structures. Eph receptors are the largest receptor tyrosine kinase family, which are divided into the A- and the B-type. Eph receptors play critical roles in embryonic development and human diseases including cancer. EphA2 is expressed in breast cancer cells and has roles in carcinogenesis, progression and prognosis of breast cancer. A homing peptide with the sequence YSAYPDSVPMMSK (YSA) that binds specifically to EphA2 was used to functionalize MSN. We focus on a novel EphA2-targeted delivery MSN system for breast cancer cells. We show that the EphA2 receptor is differentially expressed in breast cancer cells and highly expressed in the HER2-negative breast cancer cell line MCF7. Our results suggest that EphA2-targeted MSN for doxorubicin delivery (MSN-YSA-DOX) are more effective than MSN-DOX in treating breast cancer cell lines in vitro. Our preliminary observations suggest that the EphA2-targeted MSN delivery system may provide a strategy for enhancing delivery of therapeutic agents to breast cancer cells expressing EphA2, and potentially reduce toxicity while enhancing therapeutic efficacy.