C-glyco“RGD” as αIIbβ3 and αvβ integrin ligands for imaging applications: Synthesis, in vitro evaluation and molecular modeling

Methotrexate-Loaded Chitosan Oligosaccharide-ES2 for Targeted Cancer Therapy

Cancer presents a significant health threat, necessitating the development of more precise, efficient, and less damaging treatment approaches. To address this challenge, we employed the 1-ethyl-(3-dimethyl aminopropyl) carbodiimide/N-hydroxy succinimide (EDC/NHS) catalytic system and utilized quaternized chitosan oligosaccharide (HTCOSC) as a drug carrier to construct a nanoparticle delivery system termed HTCOSC-cRGD-ES2-MTX (CREM). This system specifically targets integrin αvβ3 on tumor cell surfaces and enables simultaneous loading of the antiangiogenic agent ES2 (IVRRADRAAVP) and the chemotherapy drug methotrexate (MTX). Due to its amphiphilic properties, CREM self-assembles into nanoparticles in aqueous solution, exhibiting an average diameter of 179.47 nm. Comparative studies demonstrated that CREM, in contrast to free ES2 and MTX-free nanoparticles (CRE), significantly suppressed the proliferation of EAhy926 endothelial cells and B16 melanoma cells in vitro, resulting in inhibition rates of 71.18 and 82.25%, respectively. Furthermore, CREM exhibited a hemolysis rate below 2%, indicating excellent in vitro antiangiogenic and antitumor activity as well as favorable blood compatibility. Additionally, both CRE and CREM demonstrated favorable tumor targeting capabilities through the specific binding action of cyclic RGD (cRGD) to integrin αvβ3. Further in vivo investigations revealed that CREM induced apoptosis in tumor cells via the mitochondrial apoptotic pathway and reduced the expression of angiogenic factors such as vascular endothelial growth factor (VEGF), thereby inhibiting tumor angiogenesis. This potent antitumor effect was evident through a tumor suppression rate of 80.19%. Importantly, histopathological staining (HE staining) demonstrated the absence of significant toxic side effects of CREM on various organs compared to MTX. In conclusion, the CREM nano drug delivery system synergistically enhances the therapeutic efficacy of antiangiogenic drugs and chemotherapeutic agents, thus offering a novel targeted approach for cancer treatment.

Clickable C-Glycosyl Scaffold for the Development of a Dual Fluorescent and [18F]fluorinated Cyanine-Containing Probe and Preliminary In Vitro/Vivo Evaluation by Fluorescence Imaging

Considering the individual characteristics of positron emission tomography (PET) and optical imaging (OI) in terms of sensitivity, spatial resolution, and tissue penetration, the development of dual imaging agents for bimodal PET/OI imaging is a growing field. A current major breakthrough in this field is the design of monomolecular agent displaying both a radioisotope for PET and a fluorescent dye for OI. We took advantage of the multifunctionalities allowed by a clickable C-glycosyl scaffold to gather the different elements. We describe, for the first time, the synthesis of a cyanine-based dual PET/OI imaging probe based on a versatile synthetic strategy and its direct radiofluorination via [¹⁸F]F-C bond formation. The non-radioactive dual imaging probe coupled with two c(RGDfK) peptides was evaluated in vitro and in vivo in fluorescence imaging. The binding on α_vβ₃ integrin (IC₅₀ = 16 nM) demonstrated the efficiency of the dimeric structure and PEG linkers in maintaining the affinity. In vivo fluorescence imaging of U-87 MG engrafted nude mice showed a high tumor uptake (40- and 100-fold increase for orthotopic and ectopic brain tumors, respectively, compared to healthy brain). In vitro and in vivo evaluations and resection of the ectopic tumor demonstrated the potential of the conjugate in glioblastoma cancer diagnosis and image-guided surgery.

Synthesis of anti-proliferative [3.3.0]furofuranone derivatives by lactonization and functionalization of C-glycosyl compounds

The [3.3.0]furofuranone structure is found in numerous families of biologically active natural products. We took advantage of the stereodiversity afforded by carbohydrate derivatives to prepare several compounds structurally similar to goniofufurone and crassalactones which are natural cytotoxic agents. We designed and synthesized several stereoisomers of these natural compounds via lactonization of C-glycosyl compounds bearing an hydroxyl on position 4 and a methyl ester on the pseudo-anomeric positionThe reactivity of this bicyclic moiety was explored through etherification of hydroxyls in position 5 and 7 and various substituants (halogen, phenyl, benzyl, cynanmoyl) were introduced. The anti-proliferative properties of these mimics were then evaluated on various cancer cell lines and two compounds 24 and 35 demonstrated IC₅₀ value of 1.34 µM (U251) and 7.60 µM (U87) respectively.

Synthesis of a DOTA-C-glyco bifunctional chelating agent and preliminary in vitro and in vivo study of [68Ga]Ga-DOTA-C-glyco-RGD

The design of bifunctional chelating agents (BFCA) allowing straightforward radiometal labelling of biomolecules is a current challenge. We report herein the development of a bifunctional chelating agent based on a DOTA chelator linked to a C-glycosyl compound, taking advantage of the robustness and hydrophilicity of this type of carbohydrate derivative. This new BFCA was coupled with success by CuAAC with c(RGDfK) for αvβ3 integrin targeting. As attested by in vitro evaluation, the conjugate DOTA-C-glyco-c(RGDfC) demonstrated high affinity for αvβ3 integrins (IC50 of 42 nM). [68Ga]Ga-DOTA-C-glyco-c(RGDfK) was radiosynthesized straightforwardly and showed high hydrophilic property (log D 7.4 = -3.71) and in vitro stability (>120 min). Preliminary in vivo PET study of U87MG engrafted mice gave evidence of an interesting tumor-to-non-target area ratio. All these data indicate that [68Ga]Ga-DOTA-C-glyco-c(RGDfK) allows monitoring of αvβ3 expression and could thus be used for cancer diagnosis. The DOTA-C-glycoside BFCA reported here could also be used with various ligands and chelating other (radio)metals opening a broad scope of applications in imaging modalities and therapy.

Fully automated radiosynthesis of [18F]fluoro-C-glyco-c(RGDfC): exploiting all the abilities of the AllInOne synthesizer

Fully automated and modular radiosynthesis of [¹⁸F]fluoro-C-glyco-RGD conjugate.