Quantum Dot-Based Screening Identifies F3 Peptide and Reveals Cell Surface Nucleolin as a Therapeutic Target for Rhabdomyosarcoma

Abstract

Active drug delivery by tumor-targeting peptides is a promising approach to improve existing therapies for rhabdomyosarcoma (RMS), by increasing the therapeutic effect and decreasing the systemic toxicity, e.g., by drug-loaded peptide-targeted nanoparticles. Here, we tested 20 different tumor-targeting peptides for their ability to bind to two RMS cell lines, Rh30 and RD, using quantum dots Streptavidin and biotin-peptides conjugates as a model for nanoparticles. Four peptides revealed a very strong binding to RMS cells: NCAM-1-targeting NTP peptide, nucleolin-targeting F3 peptide, and two Furin-targeting peptides, TmR and shTmR. F3 peptide showed the strongest binding to all RMS cell lines tested, low binding to normal control myoblasts and fibroblasts, and efficient internalization into RMS cells demonstrated by the cytoplasmic delivery of the Saporin toxin. The expression of the nucleophosphoprotein nucleolin, the target of F3, on the surface of RMS cell lines was validated by competition with the natural ligand lactoferrin, by colocalization with the nucleolin-binding aptamer AS1411, and by the marked sensitivity of RMS cell lines to the growth inhibitory nucleolin-binding N6L pseudopeptide. Taken together, our results indicate that nucleolin-targeting by F3 peptide represents a potential therapeutic approach for RMS.

Nucleolin‑based targeting strategies in cancer treatment: Focus on cancer immunotherapy (Review)

“…A high cytoplasmic expression of NCL is associated with a poor prognosis of patients with breast cancer, endometrial carcinoma, gastric cancer and non-small cell lung cancer (24,25,29,30) whereas a high nuclear expression of NCL is an independent good prognostic marker in gastric cancer, endometrial carcinoma and pancreatic ductal adenocarcinoma (17,24,25) (Table I). However, the surface NCL has been linked to the poor survival of patients with gastric cancer, rhabdomyosarcoma, breast cancer, hepatocellular carcinoma, colon cancer and prostate cancer (26,(31)(32)(33) (Table I). In agreement with the rational of a decrease in cell surface NCL expression or activity, several in vitro and in vivo studies showed that decreases in cell surface NCL expression or activity inhibited the growth of cancer cells and triggered apoptosis (34,35).…”

“…It also plays a critical role in anti-apoptosis (70) associated with chemoresistance in B-cell lymphoma (70), cervical cancer (81), breast cancer (82) and acute lymphoblastic leukemia (83). Several studies have described the development of molecules that target NCL on the cell surface of cancer cells to suppress or block NCL, and thereby inhibit cancer cell proliferation, apoptosis and angiogenesis (15,26,(31)(32)(33)47).…”