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Proteomic Sample Preparation from Formalin Fixed and Paraffin Embedded Tissue
Published on: September 2, 2013
Proteomic analysis of RCL2 paraffin-embedded tissues
V Bellet1, F Boissière, F Bibeau
1CHU Montpellier, Hôpital Arnaud de Villeneuve, Department of Cellular Biology, Montpellier, France.
Abstract:
Histopathological diagnosis in most of the world's hospitals is based upon formalin-fixed and paraffin-embedded (FFPE) tissues. Although this standard fixation and embedding procedure keeps the tissue in excellent form for morphological and immunohistological analysis, FFPE is inappropriate for nucleic acids and protein studies. We investigated the potential value of RCL2, a new non-toxic fixative, for sparing proteins preserved in paraffin-embedded tissues. Normal colonic mucosa tissue was fixed in RCL2 prior to paraffin embedding (RCL2P), and then processed for quality and quantity of protein conservation, as compared to frozen and FFPE tissues using complementary proteomic analysis approaches. Using 4 different protein extraction protocols, RCL2P tissue consistently showed the highest protein yield. Similar protein patterns were observed with RCL2P and frozen tissues using mono and bi-dimensional electrophoresis. Moreover, membrane, cytoplasmic and nuclear proteins, as well as phosphorylated proteins, were successfully detected using western-blot. Furthermore, protein patterns observed by mass spectrometry analysis after laser-captured microdissection were found to be identical for frozen and RCL2-fixed tissues. At last, immunohistochemistry using various antibodies showed comparable results between both tissue storage methods. We concluded that RCL2 has great potential for performing both morphological and molecular analyses on the same archival paraffin-embedded tissue sample, and can be a new method for investigating protein biomarkers.
Insights
A new fixative, RCL2, preserves proteins in paraffin-embedded tissues, outperforming standard formalin fixation (FFPE). This method enables both morphological and molecular analysis from a single tissue sample, advancing protein biomarker research.
Area of Science:
- Biochemistry
- Histology
- Proteomics
Background:
- Formalin-fixed and paraffin-embedded (FFPE) tissues are standard for histopathology but unsuitable for nucleic acid and protein studies.
- Preserving protein integrity in archival tissues is crucial for molecular analysis and biomarker discovery.
Purpose of the Study:
- To evaluate RCL2, a novel non-toxic fixative, for its efficacy in preserving proteins within paraffin-embedded tissues.
- To compare protein yield and quality from RCL2-fixed paraffin-embedded (RCL2P) tissues against frozen and FFPE tissues.
Main Methods:
- Normal colonic mucosa was fixed using RCL2, frozen, or FFPE methods.
- Proteomic analysis included protein extraction, electrophoresis (1D and 2D), western blotting, mass spectrometry (after laser-captured microdissection), and immunohistochemistry.
- Four different protein extraction protocols were employed to assess protein yield.
Main Results:
- RCL2P tissues consistently yielded the highest protein quantities across all extraction methods.
- Protein profiles from RCL2P and frozen tissues were similar via electrophoresis.
- Western blotting successfully detected various protein types (membrane, cytoplasmic, nuclear, phosphorylated) in RCL2P tissues.
- Mass spectrometry revealed identical protein patterns between frozen and RCL2-fixed tissues.
- Immunohistochemistry results were comparable between RCL2P and frozen tissues.
Conclusions:
- RCL2 fixation is a promising method for preserving protein integrity in paraffin-embedded tissues.
- RCL2 allows for both morphological and molecular analyses on the same archival tissue sample.
- This technique offers a new avenue for protein biomarker investigation using FFPE-compatible methods.
