Engineered circular RNAs (circRNAs) are a class of single-stranded RNAs with head-to-tail covalently linked structures that integrate open reading frames (ORFs) and internal ribosome entry sites (IRESs) with the function of coding and expressing proteins. Compared to mRNA vaccines, circRNA vaccines offer a more improved method that is safe, stable, and simple to manufacture. With the rapid revelation of the biological functions of circRNA and the success of Severe Acute Respiratory Coronavirus Type II (SARS-CoV-2) mRNA vaccines, biopharmaceutical companies and researchers around the globe are attempting to develop more stable circRNA vaccines for illness prevention and treatment. Nevertheless, research on circRNA vaccines is still in its infancy, and more work and assessment are needed for their synthesis, delivery, and use. In this review, based on the current understanding of the molecular biological properties and immunotherapeutic mechanisms of circRNA, we summarize the current preparation methods of circRNA vaccines, including design, synthesis, purification, and identification. We discuss their delivery strategies and summarize the challenges facing the clinical application of circRNAs to provide references for circRNA vaccine-related research.

Chemotherapy plays a major role in the treatment of cancer, but it still has great limitations in anti-tumor effect. Carboplatin (CAR) is the first-line drug in the treatment of non-small cell lung cancer, but the therapeutic effect is demonstrated weak. Therefore, we modified CAR with hexadecyl chain and polyethylene glycol, so as to realize its liposolubility and PEGylation. The synthesized amphiphilic CAR prodrugs could self-assemble into polymer micelles in water with an average particle size about 11.8 nm and low critical micelles concentration (0.0538 mg·mL^–1). In vivo pharmacodynamics and cytotoxicity experiment evidenced that the polymer micelles were equipped with preferable anti-tumor effect, finally attained the aim of elevating anti-tumor effect and prolonging retention time in vivo. The self-assembled micelles skillfully solve the shortcomings of weak efficacy of CAR, which provides a powerful platform for the application of chemical drug in oncology.

Objective: This study aimed to develop an oral celastrol-loaded self-microemulsifying drug delivery system (Cel-SMEDDS) to enhance the therapeutic efficacy against rheumatoid arthritis and reduce toxicity. Methods: The optimal Cel-SMEDDS formulation, identified through solubility screening, excipient compatibility assays, and pseudo-ternary phase diagram analysis, was characterized by particle size, PDI, zeta potential, in vitro release, and stability. In vitro anti-inflammatory activity was evaluated in LPS-induced RAW264.7 macrophages, while in vivo anti-RA efficacy was assessed in CIA mice via paw swelling, clinical scoring, serum TNF-α, and joint histopathology. Preliminary safety was examined by hematological, serum biochemical, and histopathological analyses in mice. Results: The optimal Cel-SMEDDS formulation consisted of LABRAFIL M 1944 CS-Kolliphor RH40-CAPRYOL 90 (0.2:0.48:0.32, w/w/w) with a drug loading of 1.5% (w/w). It spontaneously formed uniform microemulsions with a mean particle size of 26.70 nm, PDI of 0.067, and zeta potential of −2.87 mV. In vitro, Cel-SMEDDS showed enhanced cytotoxicity against M1-type macrophages (IC₅₀ = 0.1753 μg/mL vs. 0.2684 μg/mL for free Cel), significantly suppressed pro-inflammatory TNF-α and IL-1β expression, and upregulated anti-inflammatory IL-10. In CIA mice, oral Cel-SMEDDS reduced paw swelling by 37.42% (vs. 22.79% for free Cel), markedly decreased serum and intra-articular TNF-α levels, and alleviated articular cartilage damage. Preliminary safety evaluation demonstrated no significant abnormalities in hematological parameters, liver/kidney function, or major organ histology. Conclusions: The optimized oral Cel-SMEDDS effectively inhibits the expression of pro-inflammatory cytokine TNF-α both in vitro and in vivo, exhibits superior anti-RA activity compared to free Cel, and possesses favorable safety. This formulation addresses the key limitations of celastrol and shows promising potential for clinical translation in RA treatment.

Chemotherapy drugs are the main way to treat cancer, but there are strong toxic side effects in anti-tumor, of which oxaliplatin (OXA) is a commonly used platinum anti-tumor chemotherapy drug, colorectal cancer (CRC), non-small cell lung cancer and gastric cancer and other malignant tumors have a good therapeutic effect, but OXA also has strong side effects such as peripheral neurotoxicity, bone marrow suppression, etc. Therefore, by modifying the structure of OXA and introducing long alkyl chains in the platinum coordination of OXA, we greatly improve the fat solubility of the drug, which is more conducive to the drug crossing the biofilm and improving the anti-tumor efficacy. In addition to chemotherapy, cytokines are one of the earliest immunotherapies used in the treatment of human cancer, based on this, we prepared a new type of lipid nanoparticles (LNPs), wrapped with cytokines encoding interleukin-12 (IL12), which can directly deliver immune stimulation to tumors, and accumulate in tumors, improve the local immune environment of tumors, and directly or indirectly kill tumors. In this study, we combined the administration of modified prodrug OXA-LIP and mRNA-LNP, through in vivo pharmacodynamics and cytotoxicity experiments proving that combined administration can play a long-term anti-tumor effect, chemotherapy, and immunotherapy combination therapy is a very potential anti-tumor method, the combination of the two can play a synergistic effect, reduce the toxic side effects in tumor treatment, and the advantages in biological safety and anti-tumor activity provide broad application prospects for anti-cancer.