Green silver nanoparticles curcumin conjugate induced photodynamic therapy of lung cancer and lung cancer stem cells†

Abstract

Lung cancer remains a dreaded disease globally due to its high mortality rates. New cases of lung cancer are estimated at 1.8 million a year, with about 1.6 million deaths. Conventional treatment regimens are inefficient due to their failure to eradicate lung cancer stem cells (LCSCs). LCSCs are noted to self-renew, cause relapse, strengthen metastasis, preserve tumorigenicity, and are very resistant to treatment. This shows the need for a novel treatment modality that can target lung cancer and its stem cells. In this study, a photoactive curcumin–silver nanoparticle–polymer conjugate (Cum–PEG–BpAgNPs) was developed to enhance lung cancer photodynamic therapy (PDT). Lung cancer cells and LCSCs were treated with Cum–PEG–BpAgNPs followed by light irradiation at 470 nm. Post-analytical assays including 3-[4,5-dimethylthiazole-2yl]-2,5-diphenyl tetrazolium bromide, lactate dehydrogenase, adenosine triphosphate, ROS by DCFH-DA, annexin V-FITC/PI cell death studies, and morphological analysis were performed. The characterization analysis confirmed the bio-formulation of Cum–PEG–BpAgNPs conjugate. The LCSCs characterization indicated the presence of LCSCs in the isolated cell population. The biochemical assays post-PDT revealed substantial cytotoxicity when lower concentrations of Cum–PEG–BpAgNPs were used. The IC₅₀ value of the conjugate was noted at 4.014 μg mL⁻¹ and 2.373 μg mL⁻¹ for lung cancer cells and LCSCs, respectively. An elevated ROS production was induced, leading to apoptosis post-PDT. Therefore, Cum–PEG–BpAgNPs could be used in the mediation PDT to eliminate lung cancer cells effectively.