Nuclear localization of glutamate-cysteine ligase is associated with proliferation in head and neck squamous cell carcinoma.

Glutathione (GSH) is the keystone of the cellular response toward oxidative stress. Elevated GSH content correlates with increased resistance to chemotherapy and radiotherapy of head and neck (HN) tumors. The purpose of the present cross-sectional study was to evaluate whether the expression of glutamate-cysteine ligase (GCL) accounts for the increased GSH availability observed in HN squamous cell carcinoma (SCC). For that purpose, the messenger (m)RNA levels of the modifier (M) and catalytic (C) subunits of GCL and its putative regulators (namely, nuclear factor erythroid 2-related factor 2, heme oxygenase-1 and nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha) were monitored in 35 surgical resections of untreated HNSCC. The localization of GCLM was evaluated using