Antisense and small interfering RNA (siRNA) oligonucleotides have been recognized as powerful therapeutic compounds for targeting mRNAs and inducing their degradation. However, a major obstacle is that unmodified oligonucleotides are not readily taken up into tissues and are susceptible to degradation by nucleases. For these reasons, the design and preparation of modified DNA/RNA derivatives with better stability and an ability to be produced at large scale with enhanced uptake properties is of vital importance to improve current limitations. In the present study, we review the conjugation of oligonucleotides with lipids and peptides in order to produce oligonucleotide conjugates for therapeutics aiming to develop novel compounds with favorable pharmacokinetics.

One of the most appealing approaches for cancer treatment is targeted therapy, which is based on the use of drugs able to target cancer cells without affecting normal ones. This strategy lets to overcome the major limitation of conventional chemotherapy, namely the lack of specificity of anticancer drugs, which often leads to severe side effects, decreasing the therapy effectiveness. Delivery of cell-killing substances to tumor cells is one-way targeted drug therapy can work. Generally, monoclonal antibodies are combined with chemotherapeutic drugs, allowing cellular uptake through the binding to their targets on the surface of cancer cells. Aptamer-drug conjugates represent a promising alternative solution to antibodies to minimize off-target effects, considering the remarkable selective binding capabilities of aptamers. In this study, to enhance the therapeutic efficacy of the antineoplastic agent 5-fluoro-2'-deoxyuridine (FdU) in various cancer cells, we focused on the development of a novel conjugate using the antiproliferative aptamer T30923 (INT) as a drug vehicle. Three derivatives composed of T30923 conjugated with a different number of FdU units were synthesized, and their structural and biological properties were thoroughly characterized, highlighting their potential for targeted and synergistic anticancer responses.

Malignant melanoma presents a significant challenge in oncology due to its aggressive nature and high metastatic potential. Conventional systemic treatments often fail to effectively reach tumor sites, limiting their therapeutic impact. This study introduces a groundbreaking triple-strategy approach for treating malignant melanoma. We developed a novel prodrug, an oligonucleotide, comprising 10 units of Floxuridine (5-fluoro-2’-deoxyuridine) (FdU) nucleoside antimetabolites, to enhance half-life and reduce rapid metabolism. Encapsulated in soluble colloidal silica nanoparticles, this compound is protected and directed towards tumor neovasculature precursor endothelial cell receptors, ensuring local delivery. The strategy focuses on releasing the prodrug in the tumor microenvironment, aiming to eradicate both melanoma cells and their supportive structures. Efficacy was demonstrated in cell culture studies and preclinical models of malignant melanoma, showing a remarkable 50% reduction in tumor size after just three intravenous treatments. These findings underscore the transformative potential of targeting endothelial cell membrane proteins for drug delivery. Our study paves the way for innovative targeted therapies, promising significant advancements in treatment strategies and improved outcomes for patients with metastatic cancers. Key Points: Triple-strategy for treating melanoma: FdU ₁₀ prodrug, silica nanoparticle and targeted delivery. Oligonucleotide prodrug (Floxuridine units) enhances half-life and reduces metabolism. Soluble silica nanoparticles protect therapeutic FdU ₁₀ from nucleases and decorated with protein ligands are directed to tumor neovasculature endothelial cells. Significant 50% tumor reduction in preclinical melanoma models after systemic administration with targeted therapies.