In Situ Bioconjugation of a Maleimide-Functionalized Ruthenium-Based Photosensitizer to Albumin for Photodynamic Therapy

Robin Vinck , Orsolya Dömötör , Johannes Karges (1) , Marta Jakubaszek , Johanne Séguin (2) , Mickaël Tharaud (3) , Vincent Guérineau , Kevin Cariou (1) , Nathalie Mignet (2) , Éva A Enyedy , Gilles Gasser (1)

1 ENSCP - Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL
2 UTCBS - UM 4 (UMR 8258 / U1267) - Unité de Technologies Chimiques et Biologiques pour la Santé
3 IPGP (UMR_7154) - Institut de Physique du Globe de Paris

Maleimide-containing prodrugs can quickly and selectively react with circulating serum albumin following their injection in the bloodstream. The drug–albumin complex then benefits from longer blood circulation times and better tumor accumulation. Herein, we have applied this strategy to a previously reported highly phototoxic Ru polypyridyl complex-based photosensitizer to increase its accumulation at the tumor, reduce off-target cytotoxicity, and therefore improve its pharmacological profile. Specifically, two complexes were synthesized bearing a maleimide group: one complex with the maleimide directly incorporated into the bipyridyl ligand, and the other has a hydrophilic linker between the ligand and the maleimide group. Their interaction with albumin was studied in-depth, revealing their ability to efficiently bind both covalently and noncovalently to the plasma protein. A crucial finding is that the maleimide-functionalized complexes exhibited significantly lower cytotoxicity in noncancerous cells under dark conditions compared to the nonfunctionalized complex, which is a highly desirable property for a photosensitizer. The binding to albumin also led to a decrease in the phototoxicity of the Ru bioconjugates in comparison to the nonfunctionalized complex, probably due to a decreased cellular uptake. Unfortunately, this decrease in phototoxicity was not compensated by a dramatic increase in tumor accumulation, as was demonstrated in a tumor-bearing mouse model using inductively coupled plasma mass spectrometry (ICP-MS) studies. Consequently, this study provides valuable insight into the future design of in situ albumin-binding complexes for photodynamic therapy in order to maximize their effectiveness and realize their full potential.

Mots clés: Albumin Bioinorganic Chemistry Cancer Medicinal Inorganic Chemistry Photodynamic Therapy Ru; Albumin; Bioinorganic Chemistry; Cancer; Medicinal Inorganic Chemistry; Photodynamic Therapy; Ru

Domaines: Chimie thérapeutique

Robin Vinck, Orsolya Dömötör, Johannes Karges, Marta Jakubaszek, Johanne Séguin, et al.. In Situ Bioconjugation of a Maleimide-Functionalized Ruthenium-Based Photosensitizer to Albumin for Photodynamic Therapy. Inorganic Chemistry, 2023, ⟨10.1021/acs.inorgchem.3c01984⟩. ⟨hal-04213238⟩