Nitric oxide water-driven immunogenic cell death: Unfolding mitochondrial dysfunction's role in sensitizing lung adenocarcinoma to ferroptosis and autophagic cell death

Abstract

Non-small cell lung cancer (NSCLC), particularly lung adenocarcinoma (LUAD), significantly influences cancer-related mortality and is frequently considered by poor therapeutic responses due to genetic alterations. Cancer cells possess an inclination to develop resistance to individual treatment modalities, thus it is necessary to investigate several pathways simultaneously to obtain insights that will aid in the establishment of improved therapeutic approaches. Exploring regulated cell death (RCD) mechanisms offers promising avenues to augment immunotherapy by reshaping the tumor microenvironment (TME). Here, we investigated the prospective of microwave plasma-infused nitric oxide water (NOW) to initiate immunogenic cell death (ICD) while concurrently modulating autophagy and ferroptosis signaling in LUAD-associated A549 cells. Plasma treatment results in stable NO species nitrite/nitrate (NO2−/NO3−) in the water, altering its physicochemical properties. Analysis of ICD markers reveals increased expression of damage-associated molecular patterns (DAMPs) at both protein and mRNA levels post-NOW exposure. Intracellular reactive oxygen and nitrogen species (RONS) accumulation suggests NO-mediated mitochondrial dysfunction, triggering autophagy induction. Flow cytometry and western blotting confirm alterations in autophagy regulators Beclin 1 and SQSTM1. Furthermore, NOW treatment induces lipid peroxidation and upregulates ferroptosis-associated genes, as determined by qRT-PCR. Transmission electron microscopy (TEM) imaging reveals autophagosome formation and loss of cristae structures, corroborating the occurrence of autophagy and ferroptosis. Our findings propose that NOW may considered as inducer of ICD and the stimulation of other RCD-related proteins may enhance the anti-tumor immunogenicity.