Abstract LB_B03: Lentivirus-induced ALDH1L1 knock-in inhibits proliferation and migration and activates apoptosis of human A549 lung adenocarcinoma cells

Abstract

Abstract Lung Adenocarcinoma (LUAD), one of the most common life-threatening malignancies worldwide, represents about 40% of all lung cancers. Human Protein Atlas and OncoLnc database indicate that LUAD tumors have significantly lower mRNA levels of ALDH1L1 (10-formyltetrahydrofolate dehydrogenase, a regulatory enzyme in folate metabolism) than in non-tumor lung tissues. Moreover, higher intratumoral ALDH1L1 expression in LUAD patients correlates with better clinical outcome. These findings raise the question of whether ALDH1L1 knock-in can have a therapeutic effect. As the first step in addressing this question, we knocked-in ALDH1L1 in A549 lung adenocarcinoma cells using the lentiviral delivery. Of note, as most cancer cell lines, A549 cells do not express ALDH1L1. We have constructed the lentiviral vector carrying ALDH1L1 and green fluorescent protein (EGFP) cDNA under the control of CMV and SV40 promoters, respectively. Recombinant lentivirus (Lv-ALDH1L1), generated and packed in HEK293 cells, was used to transduce A549 cells. The efficiency of the transduction was evaluated by monitoring the GFP expression using the fluorescence microscopy of live cells. The expression of ALDH1L1 was determined at the mRNA and protein levels by RT-PCR and western blot assays, accordingly. Our results showed a significant expression of ALDH1L1 mRNA and protein expression in A549 cells carrying the Lv-ALDH1L1 vector. The lentivirus-induced ALDH1L1 elevation produced strong inhibitory effects on cellular proliferation and colony formation under nutrient-rich conditions. Of note, it also induced alterations of cell morphology. To explore the underlying mechanisms of these effects, apoptosis-related markers were examined. Elevated levels of the signal transduction pathways involved in initiating apoptosis; BID, BAX, and BAK in A549 cells transduced with Lv-ALDH1L1 were observed. Furthermore, using the wound healing assay, we showed that ALDH1L1 strongly suppresses the migratory ability of A549 cells. Interestingly, this effect was associated with a robust down-regulation of the actin depolymerizing factor cofilin and its phosphorylated form. Overall, this study demonstrated that lentiviral ALDH1L1 knock-in produces strong anti-tumorigenesis effects in A549 cells. This further suggests that ALDH1L1 should be investigated as a therapeutic drug target in cancer treatment. Citation Format: Amira Abdellatef, Sergey Krupenko. Lentivirus-induced ALDH1L1 knock-in inhibits proliferation and migration and activates apoptosis of human A549 lung adenocarcinoma cells [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 LB_B03.