A Novel Role of an Old Friend: Glutathione Protects Cells From Formaldehyde Toxicity

AGUSTIN MORELLATO; MARCO ADRIÁN SCHEIDEGGER; CARLA UMANSKY; LUCAS PONTEL

Congreso; Reunion Anual de Sociedades de Biociencia; 2020

Sociedad Argentina de Investigación Clínica

Formaldehyde (FA) is produced inside cells as a byproduct of essential biological processes such as epigenetic demethylations and the one carbon cycle. We have previously shown that human colorectal carcinoma cells lacking the FA-metabolizing enzyme alcohol dehydrogenase 5 (ADH5) cannot cope with blood concentrations of FA, which can be reverted by thiol-containing antioxidants like N-acetylcysteine (NAC) or glutathione monoethyl ester (GSH-MEE). The rescue of FA toxicity by thiol-rich antioxidants might indicate that glutathione (GSH) participates in limiting the toxicity of FA. To address this hypothesis, we used CRISPR/Cas9 to inactivate the gene coding for the regulatory unit (GCLM) of the enzyme γ-glutamatecysteine ligase (GCL), which conforms the GSH synthetic pathway, in HCT116 human colorectal carcinoma cells. The normalized viabilities against 150uM FA were WT= 72.5±7.4 μM; ΔADH5= 26.0±5.1 μM and ΔGCLM= 46.9±7.1 μM (p=0.002, Tukey comparison vs WT; n=5, mean ± SEM). Moreover, the normalized plating efficiencies (PE) in presence of 25 μM FA were WT= 90.1±6.3 %; ΔADH5= 7.9±2.7 % (P