Abstract A174: Antitumor activity of lipid nanoparticle-delivered anti-miR-21

Abstract Background: MicroRNAs (miRNAs) are small non-coding RNA molecules that play crucial roles in various biological processes, such as growth, development, aging, and apoptosis. Several studies have shown that miRNAs, including miR-21, can function as either oncogenes or tumor suppressor genes, influencing tumor initiation and progression. Aberrant expression of miR-21 has been observed in different cancer cells, indicating its significant involvement as an oncogenic miRNA in the development of various types of tumors. Antisense oligonucleotides (ASOs) have been identified as effective tools for downregulating target genes by either triggering RNase H endonuclease activity to cleave the ASO-target gene heteroduplex or by interfering with splicing and translation regulation of the target RNA sequence. ASOs have the potential to target not only mRNA but also oligonucleotides like miRNAs or small interfering RNAs (siRNAs), making them a promising approach for miRNA inhibition. However, the efficient delivery of freely circulating ASOs to the tumor microenvironment poses a challenge due to their high density of negative charges, impeding cell uptake. To address this issue, a novel lipid nanoparticle (LNP) platform called QTsome has been developed, which combines quaternary amine cationic lipids and tertiary amine ionizable lipids to enhance drug delivery. The utilization of a mixture of cationic and ionizable lipids in QTsome allows for optimal pH-dependent drug loading and release characteristics. In this study, our objective was to employ the QTsome system to deliver an ASO targeting miR-21 (AM-21) for potential tumor therapy. Methods: A total of 8E6 A549 cells were inoculated into mice, and when the tumor volume reached 100mm3, the mice were randomly divided into seven groups based on tumor volume, with each group consisting of five mice.On the day of grouping, drug administration was initiated with the following doses: 1mg/kg, every 3 days (Q3D); 2mg/kg, Q3D; 3mg/kg, Q3D; 4mg/kg, Q3D; 4mg/kg, every 4 days (Q4D); 4mg/kg, every 5 days (Q5D); 4mg/kg, every 7 days (Q7D). The drugs were administered a total of 5 times. Additionally, the A549/MC38 model was constructed using the same method. The antitumor activity of the drug and its therapeutic effect in combination with Erlotinib were evaluated in both the A549 CDX and MC38 syngeneic mouse models through intravenous injection, with a dose of 4mg/kg, Q3D. Results: The study revealed that the optimal dose for achieving the maximum antitumor effect was 4mg/kg, administered 3 times per day. In the A549 model, the tumor growth inhibition rates were 71.91%, 60.93%, and 80.44% for the AM-21/QTsome group, Erlotinib group, and the combination of AM-21/QTsome and Erlotinib group, respectively. In the MC38 mouse model, the tumor inhibition rate of AM-21/QTsome was 33.29%. Conclusion: These results emphasize the potential of miR-21 as a therapeutic target for cancer treatment, demonstrating that AM-21/QTsome holds great promise as a groundbreaking drug in this field. Citation Format: Jing Li, Qiaofang Ma, Xinyue Zhang, Xiaojie Chen, Jialiang Lin, Jun Bai, Fei Su, Xiaobin Zhao, Robert J. Lee, Yongsheng Yang. Antitumor activity of lipid nanoparticle-delivered anti-miR-21 [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr A174.