Dataset Information

Differentially embedded glioblastoma tumor protein quantitation

ABSTRACT: Glioblastoma multiforme (GBM) is the most aggressive malignant primary brain tumor with a dismal mean survival even with the current standard of care. Although in vitro cell systems can provide mechanistic insight into the regulatory networks governing GBM cell proliferation and migration, clinical samples provide a more physiologically relevant view of oncogenic signaling networks. However, clinical samples are not widely available and may be embedded for histopathologic analysis. With the goal of accurately identifying activated signaling networks in GBM tumor samples, we investigated the impact of embedding in optimal cutting temperature (OCT) compound followed by flash freezing in LN2 vs. immediate flash freezing (iFF) in LN2 on protein expression and phosphorylationmediated signaling networks. Quantitative proteomic and phosphoproteomic analysis of 8 pairs of tumor specimens revealed minimal impact of the different sample processing strategies and highlighted the large inter-patient heterogeneity present in these tumors. Correlation analyses of the differentially processed tumor sections identified activated signaling networks present in selected tumors and revealed the differential expression of transcription, translation, and degradation associated proteins. This study demonstrates the capability of quantitative mass spectrometry for identification of in vivo oncogenic signaling networks from human tumor specimens that were either OCT-embedded or immediately flash-frozen.

INSTRUMENT(S): TripleTOF 5600

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Glial Cell, Brain, Neuron Associated Cell

DISEASE(S): Brain Cancer

SUBMITTER: Hannah Johnson

LAB HEAD: Forest M White

PROVIDER: PXD001038 | Pride | 2014-07-09

REPOSITORIES: Pride

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Publications

Quantitative analysis of signaling networks across differentially embedded tumors highlights interpatient heterogeneity in human glioblastoma.

Johnson Hannah H White Forest M FM

Journal of proteome research 20140624 11

Glioblastoma multiforme (GBM) is the most aggressive malignant primary brain tumor, with a dismal mean survival even with the current standard of care. Although in vitro cell systems can provide mechanistic insight into the regulatory networks governing GBM cell proliferation and migration, clinical samples provide a more physiologically relevant view of oncogenic signaling networks. However, clinical samples are not widely available and may be embedded for histopathologic analysis. With the goa ...[more]

PMID: 24927040

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Project description:Tissue samples in biobanks preserved by formalin-fixation and paraffin-embedding (FFPE) and/or optimal cutting temperature (OCT)-embedded and subsequently freezing are highly valuable in experimental studies where the results can be related to clinical parameters. Today, mass spectrometry (MS)-based proteomics is the method of choice for unbiased and relative comparison of the abundances of thousands of proteins present in biological samples. MS analysis of FFPE- and OCT-preserved tissue has been limited, but it is now approachable using newly developed protocols. However, it has not been clarified how the results from different preservation methods agrees and differ. In this study, we use a unique sample set of urinary bladder cancer tissues of two different tumor stages (Ta/T1 – non-muscle invasive and T2/T3 muscle invasive); upon sampling the tumors were divided and preserved by the two methods. Thereafter a protocol for parallel processing of the samples were applied after which the samples were analyzed with label free quantitative MS analysis. Over 700 and 1200 proteins were quantified in FFPE and OCT samples, respectively. Principal component analysis showed that the largest differences between samples are based on the preservation method, but this analysis could also classify the tumors into different stages in each preservation. The overlap of quantifiable proteins between the preservation methods were 84% when all proteins and full data set were taken into consideration, but only 41% on average when proteins from a specific tumor were analyzed. Proteins involved in mitochondrial function were overrepresented among proteins present in OCT data but missing in the FFPE data, indicating that these proteins are not well preserved by FFPE. Moreover, univariate analysis showed that HMGCS2 protein is uniquely quantified in Ta/T1 tumors in both FFPE and OCT data, and that LGALS1, ANXA5 and plastin proteins are upregulated in T2/T3 tumors compared to Ta/T1 tumors in both FFPE and OCT data, confirming the consistency between the data sets and suggesting these proteins as biomarkers. Finally, LGALS1 data were verified by immunohistochemistry staining of an independent data set.

Project description:Background Mass spectrometry-based proteomics has become a powerful tool for the identification and quantification of proteins from a wide variety of biological specimens. To date, the majority of studies utilizing tissue samples have been carried out on prospectively collected fresh frozen or optimal cutting temperature (OCT) embedded specimens. However, such specimens are often difficult to obtain, in limited in supply, and clinical information and outcomes on patients are inherently delayed as compared to banked samples. Annotated formalin fixed, paraffin embedded (FFPE) tumor tissue specimens are available for research use from a variety of tissue banks, such as from the surveillance, epidemiology and end results (SEER) registries' residual tissue repositories. Given the wealth of outcomes information associated with such samples, the reuse of archived FFPE blocks for deep proteomic characterization with mass spectrometry technologies would provide a valuable resource for population-based cancer studies. Further, due to the widespread availability of FFPE specimens, validation of specimen integrity opens the possibility for thousands of studies that can be conducted worldwide. Methods To examine the suitability of the SEER repository tissues for proteomic and phosphoproteomic analysis, we analyzed 60 SEER patient samples, with time in storage ranging from 7 to 32 years; 60 samples with expression proteomics and 18 with phosphoproteomics, using isobaric labeling. Linear modeling and gene set enrichment analysis was used to evaluate the impacts of collection site and storage time. Results All samples, regardless of age, yielded suitable protein mass after extraction for expression analysis and 18 samples yielded sufficient mass for phosphopeptide analysis. Although peptide, protein, and phosphopeptide identifications were reduced by 50, 20 and 76% respectively, from comparable OCT specimens, we found no statistically significant differences in protein quantitation correlating with collection site or specimen age. GSEA analysis of GO-term level measurements of protein abundance differences between FFPE and OCT embedded specimens suggest that the formalin fixation process may alter representation of protein categories in the resulting dataset. Conclusions These studies demonstrate that residual FFPE tissue specimens, of varying age and collection site, are a promising source of protein for proteomic investigations if paired with rigorously verified mass spectrometry workflows. <ul><li>Dataset imported into MassIVE from <a href="https://cptac-data-portal.georgetown.edu/study-summary/S042">https://cptac-data-portal.georgetown.edu/study-summary/S042</a> on 12/08/21</li></ul>

Dataset Information

Differentially embedded glioblastoma tumor protein quantitation

Publications

Quantitative analysis of signaling networks across differentially embedded tumors highlights interpatient heterogeneity in human glioblastoma.

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