Secreted protein acidic and rich in cysteine–Albumin interaction (SPARC–Albumin interaction)

The Secreted Protein Acidic and Rich in Cysteine (SPARC)–Albumin interaction is a biochemical association exploited for the targeted delivery of chemotherapeutic agents to tumor tissues. SPARC, also known as osteonectin, is a matricellular glycoprotein involved in tissue remodeling and is frequently overexpressed in the stroma of various cancers, such as pancreatic ductal adenocarcinoma and breast cancer (UniProt P09486). Albumin is the most abundant plasma protein and serves as a natural carrier for hydrophobic molecules (UniProt P02768). The high affinity of SPARC for albumin allows for the sequestration of albumin-bound nanoparticles, such as nab-paclitaxel (Abraxane), within the tumor microenvironment, potentially increasing the local concentration of the drug (Desai et al., 2006, Clinical Cancer Research). This interaction facilitates the transport of the drug across the endothelial cell layer via gp60-mediated transcytosis and its subsequent accumulation in the SPARC-rich tumor interstitium. Although the use of SPARC expression as a predictive biomarker for patient selection remains controversial in clinical practice, the interaction remains a fundamental principle in the design of albumin-based drug delivery systems (Von Hoff et al., 2013, NEJM).

Other names

Osteonectin–Albumin interactionBM-40–Albumin interactionBasement-membrane protein 40–Albumin interactionAlbumin-SPARC axis

Exploitation of SPARC's albumin-binding affinity to facilitate the accumulation and retention of albumin-bound nanoparticle drugs within the tumor microenvironment (Desai et al., 2006).