[Quantitation of cellular phosphorylation dynamics by phosphoproteomics approaches]

Area of Science:

• Biochemistry and Molecular Biology
• Cellular Signaling and Signal Transduction

Context:

• Reversible protein phosphorylation is a critical post-translational modification regulating diverse cellular functions via signal transduction pathways.
• Dysregulated phosphorylation is implicated in various diseases, including cancer and rheumatism, often driving disease initiation and progression.
• Quantitative phosphoproteomics, utilizing mass spectrometry and enrichment techniques, enables large-scale profiling of phosphorylation sites and dynamics.

Purpose:

• To quantify the temporal phosphorylation dynamics in SKBR3 breast cancer cells in response to lapatinib, a dual inhibitor of epidermal growth factor receptor (EGFR) and EGFR2 (HER2).
• To investigate the region-specific phosphorylation changes induced by lapatinib and their impact on EGFR/HER2 signaling pathways.

Summary:

• Quantitative phosphoproteomics identified 4953 phosphopeptides from 1548 proteins in SKBR3 cells treated with lapatinib (1-10 μM).
• A small subset (5-7%) of identified phosphopeptides exhibited significant regulation (≥ twofold) upon lapatinib treatment, indicating specific signaling responses.
• The study provides a global view of cellular signaling networks affected by lapatinib, highlighting region-specific phosphorylation events critical for its anti-breast cancer activity.

Impact:

• Offers novel insights into the intricate mechanisms of EGFR/HER2 regulation through targeted phosphorylation events.
• Enhances understanding of the global cellular signaling network alterations induced by lapatinib in breast cancer.
• Contributes to the development of targeted therapies by elucidating the molecular basis of lapatinib's efficacy.