Selective induction of senescence in cancer cells through near-infrared light treatment via mitochondrial modulation.

Photobiomodulation, utilising non-ionising light in the visible and near-infrared (NIR) spectrum, has been suggested as a potential method for enhancing tissue repair, reducing inflammation and possibly mitigating cancer-therapy-associated side effects. NIR light is suggested to be absorbed intracellularly, mainly by chromophores within the mitochondria. This study examines the impact of 734 nm NIR light on cellular senescence. Cancer (MCF7 and A549) and non-cancer (MCF10A and IMR-90) cell populations were subjected to 63 mJ/cm NIR-light exposure for 6 days. Senescence levels were quantified by measuring active senescence-associated beta-galactosidase. Exposure to NIR light significantly increases senescence levels in cancer (10.0%-203.2%) but not in non-cancer cells (p > 0.05). Changes in senescence were associated with significant modulation of mitochondrial homeostasis, including increased levels of reactive oxygen species (p < 0.05) and mitochondrial membrane potential (p < 0.05) post-NIR-light treatment. These results suggest that NIR light modulates cellular chemistry, arresting the proliferation of cancer cells via senescence induction while sparing non-cancer cells.