Catalase Expression Is an Independent Prognostic Marker in Lung Adenocarcinoma

Lung adenocarcinoma (LUAD) is the deadliest cancer, and approximately 20% of stage I LUAD cases recur after surgical resection due to its high intratumor heterogeneity. Reactive oxygen species (ROS) have been detected in LUAD and are involved in carcinogenesis and tumor progression. Here, a comprehensive analysis was performed to evaluate the effects of antioxidants on the prognosis of LUAD.

The Cancer Genome Atlas (TCGA) database was used to study the relationship of gene expression of different ROS-scavenging enzymes with the progression and prognosis of LUAD.

Using TCGA LUAD datasets, we found that catalase (CAT) expression was significantly down-regulated in LUAD tissues compared to normal tissues, CAT down-regulation differed significantly between different grades of LUAD, low CAT expression was independently correlated with a worse prognosis in LUAD, and the expression of the CAT gene was associated with an inhibition of the "cell cycle". A panel of LUAD cells (CL1-0, CL1-1, CL1-3, and CL1-5), which harbored mutated p53 (R248W), with gradually increasing invasiveness showed a gradual decrease in CAT expression. Silencing of CAT upregulated cell growth in A549 cells, which harbor wild-type p53 and show high CAT expression and was associated with an increase in the expression of BUB1B, PLK1, and PKMYT1. Finally, over 38% (186/490) of LUAD cases with a p53 mutation exhibited significantly lower CAT expression than those with wild-type p53.

CAT expression is a potent favorable prognostic marker for LUAD and may represent a drug target.