Toward Personalized Peptide-Based Cancer Nanovaccines: A Facile and Versatile Synthetic Approach

Abstract

Personalized cancer vaccines (PCVs) are receiving attention as an avenue for cancer immunotherapy. PCVs employ immunogenic peptide epitopes capable of stimulating the immune system to destroy cancer cells with great specificity. Challenges associated with effective delivery of these peptides include poor solubility of hydrophobic sequences, rapid clearance, and poor immunogenicity, among others. The incorporation of peptides into nanoparticles has the potential to overcome these challenges, but the broad range of functionalities found in amino acids presents a challenge to conjugation due to possible interferences and lack of reaction specificity. Herein, a facile and versatile approach to generating nanosized PCVs under mild nonstringent conditions is reported. Following a simple two-step semibatch synthetic approach, amphiphilic hyperbranched polymer–peptide conjugates were prepared by the conjugation of melanoma antigen peptides, either TRP2 (hydrophobic) or MUT30 (hydrophilic), to an alkyne functionalized core via strain-promoted azide–alkyne click chemistry. Self-assembly of the amphiphiles gave spherical nanovaccines (by transmission electron microscopy) with sizes in the range of 10–30 nm (by dynamic light scattering). Fluorescently labeled nanovaccines were prepared to investigate the cellular uptake by antigen presenting cells (dendritic cells), and uptake was confirmed by flow cytometry and microscopy. The TRP2 nanovaccine was taken up the most followed by MUT30 nanoparticles and, finally, nanoparticles without peptide. The nanovaccines showed good biocompatibility against B16–F10 cells, yet the TRP2 peptide showed signs of toxicity, possibly due to its hydrophobicity. A test for immunogenicity revealed that the nanovaccines were poorly immunogenic, implying the need for an adjuvant when administered in vivo. Treatment of mice with melanoma tumors showed that in combination with adjuvant, CpG, groups with the peptide nanovaccines slowed tumor growth and improved survival (up to 24 days, TRP2) compared to the untreated group (14 days).

Nanoengineered targeting strategy for cancer immunotherapy

“…High levels of tumor-infiltrating T cells are associated with improved prognosis in many cancers, so it is expected that new-generation vaccines will induce effective Th1 and CD8 + CTL responses ( Fig. 1) [3,[16][17][18][19]. Efficient delivery of antigens and adjuvants to antigenpresenting cells (APCs) in lymphoid organs (peripheral lymph nodes), cytosolic delivery and cross-presentation (complexation with MHC I) of tumor-associated antigens (TAAs), and activation of DCs by appropriate stimulators are desired.…”

Peptide‐Based Supramolecular Nanodrugs as a New Generation of Therapeutic Toolboxes against Cancer

“…[107] The results demonstrated that the selfassembled spherical nanovaccines were poorly immunogenic and needed to be combined with an adjuvant CpG. For instance, personalized cancer vaccines were designed using amphiphilic hyperbranched polymer-peptide conjugates including melanoma antigen peptides, a hydrophobic peptide tyrosinaserelated protein 2 (TRP2) or a hydrophilic tumor-associated mucin 30 peptide (MUC30).…”

Non‐viral gene delivery for cancer immunotherapy

“…The balanced response of DCs plays a critical role in effective cancer immunotherapy. Therefore, NP‐based delivery systems can be employed to elicit a particular response (Table ) …”