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Published on: October 6, 2023
SILAC-Based Quantification of TGFBR2-Regulated Protein Expression in Extracellular Vesicles of Microsatellite
Fabia Fricke1,2, Malwina Michalak1,2, Uwe Warnken3
1Department Applied Tumor Biology, Institute of Pathology, Heidelberg University Hospital, Im Neuenheimer Feld 224, 69120 Heidelberg, Germany.
Abstract:
Microsatellite unstable (MSI) colorectal cancers (CRCs) are characterized by mutational inactivation of Transforming Growth Factor Beta Receptor Type 2 (TGFBR2). TGFBR2-deficient CRCs present altered target gene and protein expression. Such cellular alterations modulate the content of CRC-derived extracellular vesicles (EVs). EVs function as couriers of proteins, nucleic acids, and lipids in intercellular communication. At a qualitative level, we have previously shown that TGFBR2 deficiency causes overall alterations in the EV protein content. To deepen the basic understanding of altered protein dynamics, this work aimed to determine TGFBR2-dependent EV protein signatures in a quantitative manner. Using a stable isotope labeling with amino acids in cell culture (SILAC) approach for mass spectrometry-based quantification, 48 TGFBR2-regulated proteins were identified in MSI CRC-derived EVs. Overall, TGFBR2 deficiency caused upregulation of several EV proteins related to the extracellular matrix and nucleosome as well as downregulation of proteasome-associated proteins. The present study emphasizes the general overlap of proteins between EVs and their parental CRC cells but also highlights the impact of TGFBR2 deficiency on EV protein composition. From a clinical perspective, TGFBR2-regulated quantitative differences of protein expression in EVs might nominate novel biomarkers for liquid biopsy-based MSI typing in the future.
Insights
Microsatellite unstable colorectal cancers with TGFBR2 deficiency alter extracellular vesicle (EV) protein content. Quantitative analysis identified 48 TGFBR2-regulated proteins in EVs, suggesting potential biomarkers for cancer typing.
Area of Science:
- Oncology
- Molecular Biology
- Biochemistry
Background:
- Microsatellite unstable (MSI) colorectal cancers (CRCs) often feature mutations in the Transforming Growth Factor Beta Receptor Type 2 (TGFBR2).
- TGFBR2 deficiency impacts gene and protein expression in CRC cells, consequently altering the composition of extracellular vesicles (EVs).
- Extracellular vesicles mediate intercellular communication by transporting proteins, nucleic acids, and lipids.
Purpose of the Study:
- To quantitatively determine the protein signatures of extracellular vesicles (EVs) regulated by Transforming Growth Factor Beta Receptor Type 2 (TGFBR2) deficiency in MSI colorectal cancer (CRC).
- To deepen the understanding of altered protein dynamics in EVs due to TGFBR2 inactivation.
Main Methods:
- Utilized a stable isotope labeling with amino acids in cell culture (SILAC) approach for quantitative mass spectrometry.
- Analyzed extracellular vesicles derived from MSI colorectal cancer cells with and without TGFBR2 deficiency.
Main Results:
- Identified 48 TGFBR2-regulated proteins in extracellular vesicles from MSI colorectal cancer cells.
- Observed an upregulation of extracellular matrix and nucleosome-associated proteins and a downregulation of proteasome-associated proteins in EVs from TGFBR2-deficient cells.
- Confirmed a general overlap of proteins between EVs and their parental CRC cells, while highlighting TGFBR2's impact on EV protein composition.
Conclusions:
- TGFBR2 deficiency significantly alters the quantitative protein composition of extracellular vesicles in MSI colorectal cancer.
- The identified TGFBR2-regulated protein differences in EVs may serve as potential novel biomarkers for liquid biopsy-based MSI typing in colorectal cancer.
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