Related Experiment Video
Updated: Jun 4, 2026
Phosphopeptide Enrichment Coupled with Label-free Quantitative Mass Spectrometry to Investigate the Phosphoproteome in Prostate Cancer
Published on: August 2, 2018
Phosphoproteomic analysis of signaling pathways in head and neck squamous cell carcinoma patient samples
Mitchell J Frederick1, Amy J VanMeter, Mayur A Gadhikar
1Department of Head and Neck Surgery, University of Texas, M.D. Anderson Cancer Center, Houston, Texas, USA. mfrederi@mdanderson.org
Abstract:
Molecular targeted therapy represents a promising new strategy for treating cancers because many small-molecule inhibitors targeting protein kinases have recently become available. Reverse-phase protein microarrays (RPPAs) are a useful platform for identifying dysregulated signaling pathways in tumors and can provide insight into patient-specific differences. In the present study, RPPAs were used to examine 60 protein end points (predominantly phosphoproteins) in matched tumor and nonmalignant biopsy specimens from 23 patients with head and neck squamous cell carcinoma to characterize the cancer phosphoproteome. RPPA identified 18 of 60 analytes globally elevated in tumors versus healthy tissue and 17 of 60 analytes that were decreased. The most significantly elevated analytes in tumor were checkpoint kinase (Chk) 1 serine 345 (S345), Chk 2 S33/35, eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1) S65, protein kinase C (PKC) ζ/ι threonine 410/412 (T410/T412), LKB1 S334, inhibitor of kappaB alpha (IκB-α) S32, eukaryotic translation initiation factor 4E (eIF4E) S209, Smad2 S465/67, insulin receptor substrate 1 (IRS-1) S612, mitogen-activated ERK kinase 1/2 (MEK1/2) S217/221, and total PKC ι. To our knowledge, this is the first report of elevated PKC ι in head and neck squamous cell carcinoma that may have significance because PKC ι is an oncogene in several other tumor types, including lung cancer. The feasibility of using RPPA for developing theranostic tests to guide personalized therapy is discussed in the context of these data.
Insights
Reverse-phase protein microarrays revealed significant protein changes in head and neck cancer. This phosphoproteomic analysis identified potential biomarkers for targeted molecular therapies and theranostics.
Area of Science:
- Oncology
- Molecular Biology
- Biochemistry
Background:
- Molecular targeted therapy offers a promising approach for cancer treatment, driven by the availability of small-molecule inhibitors for protein kinases.
- Reverse-phase protein microarrays (RPPAs) are valuable tools for dissecting tumor signaling pathways and understanding patient-specific variations.
Purpose of the Study:
- To characterize the phosphoproteome of head and neck squamous cell carcinoma using RPPA.
- To identify dysregulated protein signaling pathways in tumors compared to nonmalignant tissue.
Main Methods:
- RPPAs were employed to analyze 60 protein endpoints, primarily phosphoproteins.
- Matched tumor and nonmalignant biopsy specimens from 23 head and neck squamous cell carcinoma patients were analyzed.
Main Results:
- RPPA identified 18 of 60 analytes globally elevated and 17 decreased in tumors versus healthy tissue.
- Significantly elevated proteins included checkpoint kinase 1 (Chk1) S345, Chk2 S33/35, and protein kinase C (PKC) ι.
- Elevated PKC ι, an oncogene in other cancers, was reported for the first time in head and neck squamous cell carcinoma.
Conclusions:
- RPPA successfully characterized the head and neck cancer phosphoproteome, revealing significant protein alterations.
- The findings highlight potential biomarkers for targeted therapies and suggest the utility of RPPA in developing theranostic tests for personalized cancer treatment.
