Herceptin-conjugated liposomes loaded with lipocalin-2 siRNA for the treatment of Inflammatory Breast Cancer

Inflammatory breast cancer (IBC) is a rare and aggressive subtype of breast cancer (BC) that regularly affects women younger than 40 years and accounts for 1 to 5% of all types of BC. There is not an optimal treatment for women with IBC. Approximately 40% of IBC patients are HER2+, which can be treated with the monoclonal antibody-based therapy, Herceptin (trastuzumab). However, more than 25% of patients become resistant to trastuzumab-based therapy in early stages and about 75% in late stages patients and effective second line targeted therapies are currently unavailable for IBC patients. Lipocalin-2 (LCN2) is a is a secreted protein involved in iron homeostasis, immune responses, transportation of siderophores for degradation, and epithelial cell differentiation. LCN-2 is highly abundant in certain subtypes of aggressive cancers including IBC. Reports have shown that LCN-2 is a potential target therapy for IBC patients. Here, we developed a double targeted therapy of liposomal-Herceptin formulation loaded with LCN2-targeted small interference RNA (siRNA). Trastuzumab DSPE-PEG(2000)-maleimide conjugates were synthesized for liposomal formulation, resulting in sizes of 18.3 nm and 73.7 nm for free DSPE-PEG(2000)-trastuzumab and trastuzumab-liposome, respectively. This formulation was efficiently internalized into HER2+ IBC cells, and reduced cell proliferation and tumor emboli formation in IBC cells. To further understand the molecular mechanism downstream LCN-2, we performed RNA-sequencing (RNA-seq), and we identified 139 differentially expressed genes upon siRNA-mediated LCN-2 knockdown in IBC cells. Ingenuity Pathway Analysis grouped the RNA-seq data into 25 canonical pathways altered downstream LCN-2. Together, this information suggests that LCN2-target siRNA within Herceptin-conjugated liposomes is a potential therapeutic strategy against IBC.