Cell Surface Proteomics Reveals Hypoxia-Regulated Pathways in Cervical and Bladder Cancer

Area of Science:

• Proteomics
• Cancer Biology
• Cellular Signaling

Background:

• Plasma membrane proteins (PMPs) are crucial for cell functions and are promising cancer therapeutic targets.
• Low PMP abundance hinders detection by conventional proteomic methods.

Purpose of the Study:

• To enhance the detection and identification of plasma membrane proteins (PMPs) in cancer cells under hypoxic conditions.
• To investigate hypoxia-responsive PMPs and pathways using an improved surface proteomics workflow.

Main Methods:

• Utilized a surface proteomics workflow involving cell surface biotinylation and affinity purification.
• Analyzed cervical (SiHa) and bladder (UMUC3) cancer cell lines under normoxic and hypoxic conditions.
• Employed liquid chromatography-tandem mass spectrometry (LC-MS/MS) for protein identification.

Main Results:

• Identified 43 and 32 unique hypoxia-upregulated PMPs in SiHa and UMUC3 cells, respectively, exclusively in biotin-enriched fractions.
• Detected proteins involved in extracellular matrix remodelling, immune modulation, and ion transport, not present in whole-cell lysates.
• Revealed enhanced detection of membrane-associated pathways like ECM organization and integrin signaling, with links to intracellular stress regulators.

Conclusions:

• Surface biotinylation significantly improves the sensitivity and selectivity of plasma membrane proteomics, especially under hypoxia.
• This approach successfully identifies hypoxia-responsive proteins and pathways previously undetectable by standard whole-cell analysis.
• The findings highlight novel PMPs and pathways critical for cancer progression under hypoxic stress.