Principal Investigator: Francisco Corzana
Grant Title: Carbon Dots-MUC1 conjugates: synthesis and applications of a novel class offluorescent self-adjuvating cancer vaccines.
Abstract.
Therapeutic vaccines are attracting considerable attention as
potential weapons to fight cancer through the immune system.
Mucin 1 (MUC1) is a glycoprotein found on the surface of epithelialcells. While in healthy cells the peptide backbone is decorated withcomplex carbohydrates, in cancer cells this molecule isoverexpressed and presents truncated and simple carbohydratessuch as the Tn antigen (α-O-GalNAc-Ser/Thr) that is exposed andcan be recognized by the immune system. However, MUC1-based
vaccines have low in vivo stability and are poorly immunogenic. To
enhance the immune response, we prepared a set of chemicallymodified MUC1 derivatives bearing unnatural amino acids to Prof. Francisco Corzanaenhance the antigen stability and trigger a stronger immuneresponse. Moreover, the multivalent presentation of antigens on the surface of protein carriers
or nanoparticles can improve the MUC1 immunogenicity. In this project, we explore the use ofcarbon dots (CDs) nanoparticles as novel set of carriers with inherent immunostimulant
properties to enhance the immune response. CD-MUC1 conjugation is expected to improveantigen stability and cellular internalization properties in antigen-presenting cells. Additionally,
the implementation of CDs in combination with chemically modified MUC1 variants is
expected provide a novel class of nanomaterials with high immunogenicity and high in vivo
stability for cancer vaccines.
Objectives.
The overall aim of this project is to synthesize, characterize and evaluate a novel class of selfadjuvating cancer vaccines based on unnatural MUC1 derivatives supported on CDs.
The specific objectives of this project include: i) synthesis of unnatural MUC1 derivatives; ii)
synthesis of CDs; iii) chemical conjugation and characterization of CD-MUC1 conjugates; iv)
in vivo evaluation of the immune response and tumor growth suppression studies.
Methods used.
CDs were prepared from citric acid, glucosamine, and mannose precursors following reported
procedures.1 The chemically modified MUC1 variants were prepared via standard organic
synthesis and assembled in the peptide structure through solid phase peptide synthesis.2 The
biological evaluation of CD-MUC1 conjugates was performed through cellular internalization
assays, SPR studies with anti-MUC1 antibodies, and in vivo vaccination in mice models.
Results.
The CDs and modified
MUC1 variants weresuccessfullysynthesizedandcoupled together toform the corresponding
CD-MUC1 conjugates
and the MUC1 loading
was measured via NMR
analysis showing anaverage MUC1 load of Synthesis and evaluation of CD-MUC1 conjugates~30% w/w. Initial studies in vivo demonstrated that the CD-MUC1 conjugates are non-toxic.
Preliminary in vivo assays demonstrated that the CD possess good immunostimulatory
properties and were able to elicit an immune response toward the MUC1 antigen.

1a) S.A. Hill, et al., Nanoscale, 2016, 8, 18630-18634. b) M. Ghirardello, et al., Nanoscale Adv., 2022, 4, 17701778. c) Q. Zhou, et al., ACS Nano, 2021, 15, 2929-2932.
2V.J. Somovilla, et al., J. Am. Chem. Soc., 2017, 139, 18255-18261.