Automated phosphopeptide enrichment from minute quantities of frozen malignant melanoma tissue

PLoS One. 2018 Dec 10;13(12):e0208562. doi: 10.1371/journal.pone.0208562. eCollection 2018.

Abstract

To acquire a deeper understanding of malignant melanoma (MM), it is essential to study the proteome of patient tissues. In particular, phosphoproteomics of MM has become of significant importance because of the central role that phosphorylation plays in the development of MM. Investigating clinical samples, however, is an extremely challenging task as there is usually only very limited quantities of material available to perform targeted enrichment approaches. Here, an automated phosphopeptide enrichment protocol using the AssayMap Bravo platform was applied to MM tissues and assessed for performance. The strategy proved to be highly-sensitive, less prone to variability, less laborious than existing techniques and adequate for starting quantities at the microgram level. An Fe(III)-NTA-IMAC-based enrichment workflow was applied to a dilution series of MM tissue lysates. The workflow was efficient in terms of sensitivity, reproducibility and phosphosite localization; and from only 12.5 μg of sample, more than 1,000 phosphopeptides were identified. In addition, from 60 μg of protein material the number of identified phosphoproteins from individual MM samples was comparable to previous reports that used extensive fractionation methods. Our data set included key pathways that are involved in MM progression; such as MAPK, melanocyte development and integrin signaling. Moreover, tissue-specific immunological proteins were identified, that have not been previously observed in the proteome of MM-derived cell lines. In conclusion, this workflow is suitable to study large cohorts of clinical samples that demand automatic and careful handling.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Automation
  • Chromatography, Affinity / methods*
  • Chromatography, High Pressure Liquid
  • Cluster Analysis
  • Ferric Compounds / chemistry
  • Frozen Sections
  • Humans
  • Integrins / metabolism
  • Melanoma / metabolism
  • Melanoma / pathology*
  • Mitogen-Activated Protein Kinases / metabolism
  • Phosphopeptides / analysis*
  • Phosphopeptides / isolation & purification
  • Proteome / metabolism
  • Signal Transduction
  • Tandem Mass Spectrometry

Substances

  • Ferric Compounds
  • Integrins
  • Phosphopeptides
  • Proteome
  • Mitogen-Activated Protein Kinases

Grants and funding

This work was supported by Swedish Research Council, Vinnova, SSF, under the program Biomedical engineering for better health and the Berta Kamprad Foundation; and the National Research Foundation of Korea, funded by the government of Republic of Korea (MSIP; 2012M3A9D1054520, 2015K1A1A2028365, 2015M3A9C4076 321); and Brain Korea 21 Plus Project, Republic of Korea. The funders (including the commercial company AstraZeneca) had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. AstraZeneca provided support in the form of salaries for author TM, but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of this author are articulated in the ‘author contributions’ section.