Taken together, our results reveal a novel mitophagic mechanism in lung cancer, suggesting that lung cancer-linked mutations in PARK2 are associated with impaired mitophagy and identifying DFP as a novel therapeutic agent for PARK2-linked lung cancer and possibly other types of cancers driven by mitophagic dysregulation.
In our study, we characterized the gene expression landscape of lung cancer using data obtained from TCGA to explore the changes in E3 ubiquitin ligase containing the regulators of E3 ubiquitin ligase activity.
<b>Objectives:</b> Ring finger protein 38 (RNF38), as an E3 ubiquitin ligase, plays an essential role in multiple biological processes by controlling cell apoptosis, cell cycle and DNA repair, and resides in chromosome 9 (9p13) which is involvement in cancer pathogenesis including lung cancer.
The E3 ubiquitin ligase neural precursor cell expressed developmentally downregulated 4-1 (NEDD4-1) negatively regulates phosphatase and tensin homolog deleted on chromosome 10 (PTEN) protein levels through polyubiquitination and proteolysis, but its significance in lung cancer is still unclear.
We selected eight genes, ATM serine/threonine kinase gene (ATM), BRCA2, DNA repair associated gene (BRCA2), checkpoint kinase 2 gene (CHEK2), EGFR, parkin RBR E3 ubiquitin protein ligase gene (PARK2), telomerase reverse transcriptase gene (TERT), tumor protein p53 gene (TP53), and Yes associated protein 1 gene (YAP1), on the basis of prior anecdotal association with lung cancer or genome-wide association studies.
These data reveal that the inhibition of the E3 ubiquitin ligase CHIP promotes radiosensitivity, thus suggesting a novel strategy for the treatment of lung cancer.<b>Implications:</b> The CHIP-HSP70-p21 ubiquitylation/degradation axis identified here could be exploited to enhance the efficacy of radiotherapy in patients with non-small cell lung cancer.<i></i>.
Our results provide a rationale for further investigations of this specific mutation and gene for evaluation of the possibility of developing targeted therapies against lung cancer in individuals with PARK2 variants by compensating for the loss-of-function effect caused by the associated variation.
In accordance with the developmental mode of lung cancer established by Sekine et al., we assumed that the occurrence and development of lung cancer were linked not only to gene loss in the 3p region (WNT7A, 3p25) and genetic mutations in the 9p region but also to similar events in the regions of 1p36.2 (FRAP1), 6q25.2-q27 (PARK2), and 11q13 (CCND1).