Česká společnost pro hmotnostní spektrometrii

(13. ročník České konference hmotnostní spektrometrie a 11. Neformální proteomické setkání - ThS-11)
LC-MS/MS-based terminomics unravels role of carboxypeptidase B1 in luminal A breast cancer

Petr Lapcik ^1 *, Miguel Cosenza-Contreras ², Veronika Mikulikova ¹, Pavla Bouchalova ¹, Lenka Capkova ¹, David Potesil ³, Petr Muller ⁴, Pavel Fabian ⁵, Oliver Schilling ², Pavel Bouchal ¹

1. Department of Biochemistry, Faculty of Science, Masaryk University, Brno
2. Institute of Surgical Pathology, Faculty of Medicine, University Medical Center Freiburg, Freiburg
3. Central European Institute of Technology, Masaryk University, Brno
4. Research Centre for Applied Molecular Oncology, Masaryk Memorial Cancer Institute, Brno
5. Department of Oncological Pathology, Masaryk Memorial Cancer Institute, Brno

Abstrakt

Carboxypeptidase B1 (CPB1) is a metalloprotease which cleaves arginine and lysine residues from protein C-termini and was previously associated with lymph node metastasis in low-grade luminal A breast tumors [1]. Here we aim to better understand the molecular role of CPB1 in breast cancer. To identify CPB1 protein substrates, we analyzed lymph node positive luminal A breast tumors with CPB1 (vs. CPB1 negative control) via trypsin digestion and timsTOF Pro2 LC-MS/MS system. The data were processed in Spectronaut software with semispecific search and in Fragterminomics package in R. Among 76,368 identified peptides (FDR=0.01), 17,748 peptides possessed a C-terminal non tryptic cleavage, including 23 proteins with C-terminal peptides with max. 2 arginine or lysine residues removed from the C-terminus specifically in CPB1-cleaved samples. These include PDXDC1, GANAB and NID2 proteins associated with extracellular localization and cytoskeleton. As confirmation of CPB1 role in metastatic potential of cancer cells, a 3D invasion assay showed increased volumes of spheroids formed by MCF7 cells overexpressing CPB1. To associate CPB1 with clinical-pathological parameters, CPB1 immunohistochemistry was performed for 441 breast tumors. CPB1 staining was significantly associated with lymph node status and relapse in patients of all subtypes, and specifically with relapse of luminal A tumors (n=251; p≤0.05). CPB1 histoscore was related to a shorter relapse-free (RFS) and distant metastasis free survival. Multivariable Cox analysis confirmed CPB1 as the most significant factor associated with RFS in luminal A patients. In conclusion, CPB1 seems to play a significant role in the progression of luminal A breast tumors which could be mediated by cleavage of specific protein substrates.

* Korespondující autor: lapcik@mail.muni.cz

Literatura

1. P. Bouchal, et al. Mol Cell Proteomics, 14(7):1814-30 (2015)

Poděkování:

Supported by the National Institute for Cancer Research (Program EXCELES, ID LX22NPO5102) – Next generation EU.