Abstract 3710: Combinatorial micro RNA therapy can be used as potential cell cycle inhibitors to treat lung cancer

Lung cancer (LC) is the leading cause of cancer-related deaths worldwide. Among the 18.1 million of total cancer patients last year, 2.1 million of the new cases were of LC worldwide. The poor prognosis, higher incidence, and mortality rate make this disease a devastating type of cancer. Cell cycle inhibition is one of the prominent choices among researchers in cancer treatment. Different cell cycle inhibitors are developed by scientists where the cyclin-dependent kinase (CDK) inhibitors are among the most frequently researched. Just recently, 3 CDK inhibitors received FDA-approval for treatment of specific breast cancer subtypes, but no CDK inhibitors currently exist for LC patient treatment. Thus, there is a need for molecules that regulate cell cycle progression and CDK expression. Micro RNAs (miRNAs) are gene-expression regulatory molecules. Among several miRs, we selected miR-143 and miR-506 to regulate CDK1 and CDK4/6, respectively. qPCR and RNA-sequencing indicated that this combinatorial miR therapy caused downregulation of the respective CDK1, 4, and 6 genes in H358 and H1975 lung cancer cell lines. This RNA inhibition corresponded to protein levels downregulation, as detected by western blot analysis. Further investigation found that this treatment caused significant halt of the cell cycle progression, which is markedly stronger than the commercially available CDK inhibitors, Ribociclib and Flavopiridol. We also identified the combined miR-143 and miR-506 caused significant increase of the apoptotic cell population at both 24 and 48 h post-treatment, as detected by an Annexin V/PI analysis. Interestingly, low or no apoptotic impact was observed in HFL1 normal lung fibroblast cells by the combinatorial miR treatment, indicating a cancer-cell specific activity. Upstream pathway analysis through RNA-sequencing using Ingenuity Pathway Analysis software (IPA; Qiagen) indicated a potential ERK-mediation on the activity of the combinatorial miR treatment. Our analysis of the ERK pathway using MAPK (ERK) inhibitors indicated an ERK-independent cell cycle inhibitory activity of the two miRs. Through further analysis of the RNA-Seq data, we observed a potential inhibition of the cellular migration and invasion activity of the cells, which was confirmed by a cell migration assay. In summary, combinatorial treatment of miR-143 and miR-506 has a significant impact on the cell cycle, overall survival, and migration of LC cells, which still merits further study. Citation Format: A K M Nawshad Hossian. Combinatorial micro RNA therapy can be used as potential cell cycle inhibitors to treat lung cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3710.