A novel role of an old friend: Cellular glutathione protects cells from formaldehyde toxicity

AGUSTÍN MORELLATO; MARCO SCHEIDEGGER ; CARLA UMANSKY ; MANUELA R. MARTINEFSKI; ARACELI FERNANDEZ ; MARIELA BOLLINI; MARÍA EUGENIA MONGE ; LUCAS PONTEL

Conferencia Virtual

Congreso; SAIC; 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 the major intracellular thiol-rich antioxidant glutathione (GSH) participates in limiting the toxicity of endogenous 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 FA LC50s were WT = 174.0±8.7 μM; ΔADH5 = 83.9±8.7 μM and ΔGCLM= 142.1±6.8 μM (n=5, mean ± SEM). Moreover, the plating efficiencies (PE) in presence of 25 μM FA compared to the PE of untreated cells were WT = 90.1±6.3 %; ΔADH5 = 7.9±2.7 % (P