Starting a new chapter on class Ia ribonucleotide reductases

Deferasirox's Anti-Chemoresistance and Anti-Metastatic Effect on Non-Small Cell Lung Carcinoma

Clinically approved iron chelators, originally designed to address iron overload disorders, have emerged as potential anticancer agents. Deferasirox (Def), a tridentate iron chelator, has demonstrated antiproliferative effects in cancer. Background/Objectives: This study aims to elucidate the mechanism of action of Def and its impact on non-small cell lung carcinoma (NSCLC). Methods: NSCLC A549 cells were treated with Def to assess cytotoxicity, the effect on nuclear and mitochondrial pathways, and iron-containing proteins and genes to evaluate anti-metastasis and chemoresistance. A lung carcinoma mouse model was used for in vivo studies. Results: Our findings revealed that Def induced cytotoxicity, effectively chelated intracellular iron, and triggered apoptosis through the increase in phosphatidylserine externalization and caspase 3 activity. Additionally, Def caused G0/G1 cell cycle arrest by downregulating the ribonucleotide reductase catalytic subunit. Furthermore, Def perturbed mitochondrial function by promoting the production of reactive oxygen species and the inhibition of glutathione as a measurement of ferroptosis activation. Def demonstrated inhibitory effects on cell migration in scratch assays, which was supported by the upregulation of n-myc downstream-regulated gene 1 and downregulation of the epidermal growth factor receptor protein. Also, Def downregulated one of the main markers of chemoresistance, the ABCB1 gene. In vivo experiments using a lung carcinoma mouse model showed that Def treatment did not affect the animal's body weight and showed a significant decrease in tumor growth. Conclusions: This investigation lays the groundwork for unraveling Def action's molecular targets and mechanisms in lung carcinoma, particularly within iron-related pathways, pointing out its anti-metastasis and anti-chemoresistance effect.

An easy method for quantification of anaerobic and microaerobic gene expression with fluorescent reporter proteins

Fluorescent proteins, such as green fluorescent proteins, are invaluable tools for detecting and quantifying gene expression in high-throughput reporter gene assays. However, they introduce significant inaccuracies in studies involving microaerobiosis or anaerobiosis, as oxygen is required for the maturation of these proteins' chromophores. In this study, the authors highlight the errors incurred by using fluorescent proteins under limited oxygenation by comparing standard fluorescence-based reporter gene assays to quantitative real-time PCR data in the study of a complex oxygen-regulated gene network. Furthermore, a solution to perform quantification of anaerobic and microaerobic gene expression with fluorescent reporter proteins using a microplate reader with an oxygen control system and applying pulses of full oxygenation before fluorescence measurements is provided.

Formate-producing capacity provided by reducing ability of Streptococcus thermophilus nicotinamide adenine dinucleotide oxidase determines yogurt acidification rate

Yogurt is made by fermenting milk with 2 lactic acid bacteria, Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus thermophilus. To comprehensively understand the protocooperation mechanism between S. thermophilus and L. bulgaricus in yogurt fermentation, we examined 24 combinations of cocultures comprising 7 fast- or slow-acidifying S. thermophilus strains with 6 fast- or slow-acidifying L. bulgaricus strains. Furthermore, 3 NADH oxidase (Nox)-deficient mutants (Δnox) and one pyruvate formate-lyase deficient mutant (ΔpflB) of S. thermophilus were used to evaluate the factor that determines the acidification rate of S. thermophilus. The results revealed that the acidification rate of S. thermophilus monoculture determined the yogurt fermentation rates, despite the coexistence of L. bulgaricus, whose acidification rate was either fast or slow. Significant correlation was found between the acidification rate of S. thermophilus monoculture and the amount of formate production. Result using ΔpflB showed that the formate was indispensable for the acidification of S. thermophilus. Moreover, results of the Δnox experiments revealed that formate production required Nox activity, which not only regulated dissolved oxygen, but also the redox potential. The Nox provided the large decrease in redox potential required by pyruvate formate-lyase to produce formate. A highly significant correlation was found between formate accumulation and Nox activity in S. thermophilus. In conclusion, the formate production ability provided by the action of Nox activity determines the acidification rate of S. thermophilus, and consequently, regulates yogurt coculture fermentation.