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Updated: Oct 15, 2025
Experimental Metastasis Assay
Published on: August 24, 2010
Targeted Quantitative Profiling of GTP-Binding Proteins Associated with Metastasis of Melanoma Cells
Rong Cai1,2, David Bade3, Xiaochuan Liu1
1Department of Chemistry, University of California, Riverside, Riverside, California 92521, United States.
Abstract:
Metastasis is a major obstacle in the therapeutic intervention of melanoma, and several GTP-binding proteins were found to play important roles in regulating cancer metastasis. To assess systematically the regulatory roles of these proteins in melanoma metastasis, we employed a targeted chemoproteomic method, which relies on the application of stable isotope-labeled desthiobiotin-GTP acyl phosphate probes in conjunction with scheduled multiple-reaction monitoring (MRM), for profiling quantitatively the GTP-binding proteins. Following probe labeling, tryptic digestion, and affinity pull-down of desthiobiotin-conjugated peptides, differences in expression levels of GTP-binding proteins in two matched pairs of primary/metastatic melanoma cell lines were measured using liquid chromatography-MRM analysis. We also showed that among the top upregulated proteins in metastatic melanoma cells, AK4 promotes the migration and invasion of melanoma cells; overexpression of AK4 in primary melanoma cells leads to augmented migration and invasion, and reciprocally, knockdown of AK4 in metastatic melanoma cells results in repressed invasiveness. In summary, we examined the relative expression levels of GTP-binding proteins in two pairs of primary/metastatic melanoma cell lines. Our results confirmed some previously reported regulators of melanoma metastasis and revealed a potential role of AK4 in promoting melanoma metastasis.
Insights
This study identifies key GTP-binding proteins involved in melanoma metastasis using chemoproteomics. The protein AK4 was found to promote melanoma cell migration and invasion, highlighting its potential role in cancer progression.
Area of Science:
- Oncology
- Biochemistry
- Proteomics
Background:
- Melanoma metastasis presents a significant challenge in cancer therapy.
- GTP-binding proteins are implicated in regulating cancer metastasis.
- Understanding these regulatory roles is crucial for developing effective treatments.
Purpose of the Study:
- To systematically assess the regulatory roles of GTP-binding proteins in melanoma metastasis.
- To quantitatively profile GTP-binding proteins using a targeted chemoproteomic approach.
- To identify novel protein regulators involved in melanoma progression.
Main Methods:
- Utilized a targeted chemoproteomic method with stable isotope-labeled desthiobiotin-GTP acyl phosphate probes.
- Employed scheduled multiple-reaction monitoring (MRM) for quantitative profiling.
- Analyzed protein expression differences in matched primary/metastatic melanoma cell lines via liquid chromatography-MRM.
Main Results:
- Quantitatively profiled GTP-binding proteins in primary versus metastatic melanoma cell lines.
- Identified AK4 as a significantly upregulated protein in metastatic melanoma cells.
- Demonstrated that AK4 overexpression enhances melanoma cell migration and invasion, while AK4 knockdown reduces invasiveness.
Conclusions:
- Confirmed known regulators of melanoma metastasis and identified novel candidates.
- Revealed a potential role for AK4 in promoting melanoma cell migration and invasion.
- The findings suggest AK4 as a potential therapeutic target for melanoma metastasis.
