Objective To investigate the effect of ATP synthase inhibitory factor 1 (ATPIF1) on the antitumor activity of chimeric antigen receptor (CAR)-NK92 cells. Methods HER2-targeted CAR-NK92 cells with ATPIF1 overexpression or knockdown were constructed. CAR-positive expression rate was detected by flow cytometry. Cell proliferation capacity was measured using CCK-8 assay. Glycolytic capacity was analyzed by Seahorse metabolic analyzer. Mitochondrial membrane potential levels were detected using JC-1 probe. Target cell lysis rate was evaluated by firefly luciferase reporter assay. Expression levels of CD107a, natural-killer group 2 member D (NKG2D), granzyme B (GzmB), perforin, and interleukin 2 (IL-2) were detected via flow cytometry. Quantitative real-time PCR was used to measure the expression of interferon-induced protein with tetratricopeptide repeats 1 (IFIT1), tumor necrosis factor α (TNF-α), ATPIF1, and hexokinase 1 (HK1). The impact of glycolytic inhibition by 2-Deoxy-D-glucose (2-DG) on CAR-NK92 antitumor capacity was examined. Results Successfully generated HER2-targeting control CAR-NK92 cells, as well as ATPIF1-overexpressing and ATPIF1 knockdown CAR-NK92 cells. The ATPIF1-overexpressing CAR-NK92 cells showed significantly enhanced target cell lysis rate, elevated expression levels of NKG2D and CD107a, increased secretion capacities of Granzyme B (GzmB) and IL-2, and upregulated mRNA expression levels of IFIT1 and TNF-α, while ATPIF1-knockdown cells exhibited opposite effects. ATPIF1 overexpression induced metabolic reprogramming in CAR-NK92 cells, manifested by significantly decreased mitochondrial membrane potential (δpsim), markedly upregulated HK1 mRNA expression, and enhanced basal glycolysis and glycolytic capacity. After glycolysis inhibition with 2-DG (5 μmol/L), both ATPIF1-overexpressing and knockdown CAR-NK92 cells showed no significant differences in NKG2D and CD107a expression levels compared to control cells. Conclusion ATPIF1 regulates the antitumor activity of CAR-NK92 cells through modulating glycolytic metabolism. Overexpression of ATPIF1 can enhance the antitumor efficacy of CAR-NK92 cells.
Humans ; Glycolysis ; Killer Cells, Natural/metabolism* ; Receptors, Chimeric Antigen/immunology* ; Granzymes/genetics* ; Hexokinase/metabolism* ; Cell Line, Tumor ; Interleukin-2/genetics* ; Cell Proliferation ; NK Cell Lectin-Like Receptor Subfamily K/genetics* ; Membrane Potential, Mitochondrial