Investigating the molecular effects of hyperbranched polycation-DNA complexes on lung cancer cells using LC-MS-based metabolite profiling

Introduction: Gene therapy has been considered a promising approach for addressing hereditary and acquired diseases since the first clinical trials in 1990. However, no gene therapy application has been approved by FDA yet due... [ view full abstract ]

Introduction: Gene therapy has been considered a promising approach for addressing hereditary and acquired diseases since the first clinical trials in 1990. However, no gene therapy application has been approved by FDA yet due to the biological and technical barriers facing gene delivery. Hyperbranched cationic polymers have emerged as attractive gene delivery systems, they are cheap to scale up and easy to functionalise. However, the impact of their nanosized polyplexes form at the cellular and molecular level is not fully studied.

Methodology: Polylysine and polylysine-co-histidine were synthesised using conventional thermal condensation method. In addition to polyethyleneimine, the prepared polymers were used to fabricate nanosized polyplexes by mixing with noncoding plasmid DNA, cell-based global metabolic profiling was employed to investigate the impact of these polycation-DNA polyplexes (PCDP) on the metabolism of A459 and H1299 lung carcinoma cell lines.

Results: The study revealed that PCDPs have altered many metabolic pathways in both cell lines. Interestingly, PCDPs have induced oxidative stress and inflammatory response in A459 cells and only oxidative stress in H1299 cells. On the other hand, previous transfection experiments showed that the branched polymers were more efficient in H1299 than A459 which might indicate that the inflammatory response suppresses the transfection. Aspirin and N-acetyl cysteine were used to minimise the inflammatory response and the oxidative stress respectively. Aspirin has enhanced the transfection in H1299 cells more efficiently than A549 ones and has slightly decreased the transfection in both cell lines.

Discussion: Interestingly Aspirin enhanced the transfection in the cells that showed no inflammatory response which indicates that Aspirin can enhance the transfection by unknown mechanisms other than its anti-inflammatory effect. According to literature, N-acetyl cysteine is supposed to enhance the transfection by suppressing the oxidative stress, however, the results suggest that the oxidative stress aids the transfection by PCDP either by facilitating their lysosomal escape or entry to nucleus.