MSACL 2019 EU Abstract

MALDI-TOF MSI of MeLiM Melanoma: Searching for Differences in Protein Profiles

Lucie Vanickova (1), Roman Guran (1,2), Vratislav Horak (3), Vojtěch Adam (1,2)
(1) Mendel University in Brno, Brno, Czech Republic (2) Central European Institute of Technology, Brno University of Technology, Brno, Czech Republic (3) Institute of Animal Physiology and Genetics, Academy of Sciences of the Czech Republic, v.v.i., Libechov, Czech Republic

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Lucie Vanickova (Presenter) Mendel University in Brno

Relevant Financial Disclosures (within past 24 months) Grant/Research Support Marie Skłodowska- Curie programme co-financed by the South Moravian Region (No. 665860) Salary Mendel University in Brno Conflict mitigation NOT REQUIRED.

Introduction: Treatment of advanced cutaneous melanoma remains challenging, and new data on melanoma biology are required. The most widely accepted criteria for the prognostic evaluation of melanoma are histopathological and clinical parameters, and the identification of additional tumor markers is thus of paramount importance. Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI), an important tool in cancer research, is useful for unraveling the molecular profile of melanoma.

Objectives: In this report, we used the melanoma-bearing Libechov minipig (MeLiM), a unique animal model that allows observation of the complete spontaneous regression of invasive cutaneous melanoma, to investigate i) the differences between melanoma and healthy skin protein profiles and ii) the proteins potentially involved in spontaneous regression.

Methods: The MeLiM tissues were cryosected, histologically characterized, analyzed by MALDI MSI, and immunohistologically stained. Multivariate statistical analyses of the MALDI MSI data revealed ten relevant m/z ions, of which the expression levels varied significantly among the studied MeLiM tissues. These ion peaks were used to create mass ion images/maps and visualize the differences between tumor and healthy skin specimens, as well as among histologically characterized tissue regions.

Results: Protein profiles comprising ten statistically significant mass ion peaks useful for differentiating cutaneous melanoma and healthy skin tissues were determined. Peaks at m/z 3044, 6011, 6140 and 10180 were overexpressed in melanoma compared with healthy skin tissue. More specifically, m/z 6140 was expressed at significantly (p < 0.05) higher levels in normally growing melanoma regions than in regions with early and late spontaneous regression.

Conclusion: This study demonstrates the clinical utility of MALDI MSI for the analysis of tissue cryosections at a molecular level.