Integrative Analysis of Proteome and Ubiquitylome Reveals Unique Features of Lysosomal and Endocytic Pathways in...

Area of Science:

• Oncology
• Molecular Biology
• Biochemistry

Background:

• Gefitinib resistance is a major challenge in treating EGFR-mutated non-small cell lung cancer (NSCLC).
• Protein ubiquitylation, a key posttranslational modification, influences protein stability and function, but its role in gefitinib resistance remains unclear.
• Understanding these molecular changes is crucial for developing strategies to overcome drug resistance.

Purpose of the Study:

• To systematically identify global changes in protein expression and ubiquitylation in gefitinib-resistant versus sensitive NSCLC cells.
• To elucidate the role of protein ubiquitylation in the development of gefitinib resistance.
• To uncover potential therapeutic targets for overcoming gefitinib resistance.

Main Methods:

• Quantitative global proteomic and ubiquitylome analysis using mass spectrometry.
• Comparison of protein expression and ubiquitylation profiles between gefitinib-resistant and sensitive NSCLC cell lines.
• Bioinformatic analysis to identify enriched pathways and differentially modified proteins.

Main Results:

• Quantified expression changes in 3773 proteins and ubiquitylation changes at 2893 lysine sites across 1415 proteins.
• Identified enrichment of lysosomal and endocytic pathways, involved in autophagy regulation, in gefitinib-resistant cells.
• Demonstrated that HMGA2 overexpression or ALOX5 knockdown suppresses gefitinib resistance by inhibiting autophagy.

Conclusions:

• Revealed novel global ubiquitylome and proteomic features associated with gefitinib resistance in NSCLC.
• Uncovered opposing roles of HMGA2 and ALOX5 in regulating gefitinib resistance and autophagy.
• These findings provide insights into potential therapeutic strategies for overcoming gefitinib resistance.