A Deep Dive: SIWV Tetra-Peptide Enhancing the Penetration of Nanotherapeutics into the Glioblastoma.

Glioblastoma multiforme (GBM) is the most aggressive malignant tumor. It is difficult to regulate GBM using conventional chemotherapy-based methods due to its anatomical structure specificity, low drug targeting ability, and limited penetration depth capability to reach the tumor interior. Numerous approaches have been proposed to overcome such issues, including nanoparticle-based drug delivery system (DDS) with the development of GBM site targeting and penetration depth enhancing moieties (e.g., peptides, sugars, proteins, etc.). In this study, we prepared four different types of nanoparticles, which are based on porous silicon nanoparticles (pSiNPs) incorporating polyethylene glycol (PEG), iRGD peptide (well-known cancer targeting peptide), and SIWV tetra-peptide (a recently disclosed GBM-targeting peptide), and analyzed their deep-tumor penetration abilities in cell spheroids, in GBM patient-derived tumoroids, and in GBM xenograft mice. We found that SIWV tetra-peptide significantly enhanced the penetration depth of pSiNPs, and its therapeutic formulation (temozolomide-loaded/SIWV-functionalized pSiNPs) showed a higher anticancer efficacy compared with other formulations. These findings hold great promise for the development of nanotherapeutics and peptide-conjugated drugs for GBM.