Abstract PO3-26-12: Targeting Lipocalin-2 in HER2+ Inflammatory Breast Cancer Using Herceptin-Conjugated Liposomes
Authors: Flores-Colón Marienid , Vivas-Rivera Pablo , Vivas-Mejía Pablo E. 
Published: May 2024

Abstract
Inflammatory breast cancer (IBC) is a rare and aggressive subtype of BC that accounts for 1 to 5% of all types of BC. Due to its inflammatory characteristics and the absence of a palpable mass, IBC is usually confounded with a mastitis. Unfortunately, once properly diagnosed, IBC has already metastasized. A high portion of IBC tumors overexpress human epidermal growth factor receptor 2 (HER2). These IBC patients (HER2+) are treated with Trastuzumab, a monoclonal antibody. However, many IBCs become resistant to this therapy. Thus, there is not an optimal treatment against this horrendous disease. One potential target against IBC is Lipocalin-2 (LCN2), a secreted protein involved in iron homeostasis, immune responses, transport of siderophores, and epithelial cell differentiation. In many aggressive tumors, high levels of LCN2 have been associated with increased cancer cell motility, proliferation, angiogenesis, invasion, and metastasis. LCN2 is aberrantly abundant in IBCs compared with non-IBC patients and cell lines. This information indicates that LCN2 could be a target for IBC therapy. Our research team showed that small interference RNAs (siRNAs) targeting LCN2 effectively reduced the cell proliferation and invasion ability of IBC cells. To systemically deliver siRNA specifically to HER2+ IBC cells, we prepared Herceptin-conjugated liposome loaded with siRNA against LCN2. Trastuzumab conjugated liposomes werecharacterized by using dynamic light scattering to measure the size distribution and the zeta potential. Our formulation displayed sizes of 18.3 and 73.7 nm which could correspond to free DSPE-PEG-(2000) trastuzumab and the trastuzumab-liposome, respectively. To determine the optimal timepoint of liposome internalization into IBC cell lines, we incubated HER2+ IBC3 cells with liposomes for different time-points. Optimal internalization was observed at 24 and 48-hr. To further understand the downstream effectors of LCN2 in IBC cells, we performed RNAseq in siRNA-mediated LCN2 knockdown cells. Further bioinformatics with the RNAseq data, revealed 138 dysregulated genes following LCN2 knockdown as compared with a negative control (NC) siRNA. Particularly, increased STAT1 levels has been associated with to distant metastasis and poor clinical prognosis in cancer. In our study, STAT1 levels decreased after LCN2 silencing. Ingenuity Pathway Analysis (IPA) showed 25 canonical pathways altered in the LCN2 knockdown cells as compared with the NC-siRNA. These results indicate that LCN2 activate molecular pathways involved in cell proliferation, invasion and metastasis in IBC cells.
Citation Format: Marienid Flores-Colón, Pablo Vivas-Rivera, Pablo E. Vivas-Mejía. Targeting Lipocalin-2 in HER2+ Inflammatory Breast Cancer Using Herceptin-Conjugated Liposomes [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-26-12.