Deubiquitomic and bioinformatic analyses in cisplatin-treated lung cancer cells

Introduction: Lung cancer is a highly lethal disease characterized by a significant mortality rate. Cisplatin, a common drug used for lung cancer treatment, frequently develops resistance over time. Therefore, overcoming cisplatin resistance is crucial in the effective management of lung cancer. The ubiquitin-proteasome system (UPS) serves as a vital regulatory mechanism for maintaining protein homeostasis within cells. Recent studies have shown that manipulating deubiquitinating enzymes (DUBs) can overcome cisplatin resistance. This study aims to investigate the expression levels of DUBs under cisplatin treatment. Methods: Multiplex RT-PCR analysis was performed to identify potential biomarkers by comparing the differential expression patterns of DUBs, and their expression levels were analyzed by RT-qPCR. In addition, their protein expression levels were determined by western blot analysis. The bioinformatics tools including TCGA database and GEPIA website were used to validate potential as prognostic markers in lung cancer. Results: Multiplex RT-PCR analysis was performed to identify potential biomarkers by comparing the differential expression patterns of DUB genes. Multiplex RT-PCR showed distinct mRNA expression profiles of several DUB genes, including USP35, USP36, USP37, USP47, USP49, and OTUD6B in A549 lung cancer cells following exposure to cisplatin. In addition, RT-qPCR analysis revealed the downregulation of USP35, USP36, USP37, USP47, USP49, and OTUD6B, juxtaposed with the upregulation of USP47 under cisplatin treatment. Substantiating these findings, western blotting analysis confirmed the protein expression levels of USP35, USP36, USP37, USP47, USP49, and OTUD6B in cisplatin-treated lung cancer cells, mirroring the mRNA trends observed in non-treated counterparts except for OTUD6B. Bioinformatics analysis demonstrates that these DUBs except USP47 are upregulated and overall survival analysis indicates that lower expression of these DUBs, except USP37 and USP49, is correlated with improved overall survival in lung cancer patients. Conclusion: These findings strongly suggest that DUBs may play a crucial role in overcoming cisplatin resistance and improving the treatment efficacy for lung cancer.