| 1. |
- Bauden, Monika, et al.
(författare)
-
Characterization of histone-related chemical modifications in formalin-fixed paraffin-embedded and fresh-frozen human pancreatic cancer xenografts using LC-MS/MS
- 2017
-
Ingår i: Laboratory Investigation. - : Elsevier BV. - 0023-6837. ; 97:3, s. 279-288
-
Tidskriftsartikel (refereegranskat)abstract
- Post-translational modifications (PTMs) of histones including acetylation, methylation, and ubiquitination are known to be involved in the epigenetic regulation of gene expression and thus can have an important role in tumorigenesis. A number of PTMs have been linked to pancreatic cancer and are frequently studied as potential targets for cancer therapy or diagnosis. The availability of biobank-stored, formalin-fixed, paraffin-embedded (FFPE) materials and advanced proteomic analytical tools make it possible to detect histone-related PTMs using predicted mass shifts caused by specific modification. It is, however, important to take into account the fact that formaldehyde (FA) present in the FFPE material is chemically reactive and may undergo condensation reactions, for example, with terminal amino groups and active CH functionalities of the studied proteins. As supported by the results of this study, the possibility to misinterpret such protein condensation product as endogenous PTMs should be taken into consideration in all proteomic analytical work involving FFPE materials. In this study, we used liquid chromatography-tandem mass spectrometry to assess preassumed modification of the lysine residues of histone proteins in FFPE or fresh-frozen (FF) tumor xenografts, derived from the human pancreatic cancer cell line, Capan-1. Here we report modifications with a defined mass shift of +14.016, +28.031, +42.011, or +114.043 Da, corresponding to apparent methylation, dimethylation, acetylation, or ubiquitination that were differentially distributed between the groups. The identified modifications were significantly more frequent in FFPE samples as compared with FF samples. Our results indicate that FFPE tissue processing may result in persistent chemical modifications of histones, which correspond in mass shift of important PTMs. Herein, we highlight the importance to investigate and report FA-formed modifications in FFPE-treated tissues, as well as the necessity of careful manual examination of observed modifications to eliminate false-positive PTMs.
|
|
| 2. |
- Bauden, Monika, et al.
(författare)
-
Histone profiling reveals the H1.3 histone variant as a prognostic biomarker for pancreatic ductal adenocarcinoma
- 2017
-
Ingår i: BMC Cancer. - : Springer Science and Business Media LLC. - 1471-2407. ; 17:1
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Epigenetic alterations have been recognized as important contributors to the pathogenesis of PDAC. However, the role of histone variants in pancreatic tumor progression is still not completely understood. The aim of this study was to explore the expression and prognostic significance of histone protein variants in PDAC patients. Methods: Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was employed for qualitative analysis of histone variants and histone related post-translational modifications (PTMs) in PDAC and normal pancreatic tissues. Survival analysis was conducted using the Kaplan-Meier method and Cox proportional hazards regression. Results: Histone variant H1.3 was found to be differentially expressed (p = 0.005) and was selected as a PDAC specific histone variant candidate. The prognostic role of H1.3 was evaluated in an external cohort of patients with resected PDAC using immunohistochemistry. Intratumor expression of H1.3 was found to be an important risk factor for overall survival in PDAC, with an adjusted HR value of 2.6 (95% CI 1.1-6.1), p = 0.029. Conclusion: We suggest that the intratumor histone H1.3 expression as reported herein, may serve as a new epigenetic biomarker for PDAC.
|
|
| 3. |
- Byrling, Johannes, et al.
(författare)
-
Mass spectrometry-based analysis of formalin-fixed, paraffin-embedded distal cholangiocarcinoma identifies stromal thrombospondin-2 as a potential prognostic marker
- 2020
-
Ingår i: Journal of Translational Medicine. - : Springer Science and Business Media LLC. - 1479-5876. ; 18:1
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Distal cholangiocarcinoma is an aggressive malignancy with a dismal prognosis. Diagnostic and prognostic biomarkers for distal cholangiocarcinoma are lacking. The aim of the present study was to identify differentially expressed proteins between distal cholangiocarcinoma and normal bile duct samples. Methods: A workflow utilizing discovery mass spectrometry and verification by parallel reaction monitoring was used to analyze surgically resected formalin-fixed, paraffin-embedded samples from distal cholangiocarcinoma patients and normal bile duct samples. Bioinformatic analysis was used for functional annotation and pathway analysis. Immunohistochemistry was performed to validate the expression of thrombospondin-2 and investigate its association with survival. Results: In the discovery study, a total of 3057 proteins were identified. Eighty-seven proteins were found to be differentially expressed (q < 0.05 and fold change ≥ 2 or ≤ 0.5); 31 proteins were upregulated and 56 were downregulated in the distal cholangiocarcinoma samples compared to controls. Bioinformatic analysis revealed an abundance of differentially expressed proteins associated with the tumor reactive stroma. Parallel reaction monitoring verified 28 proteins as upregulated and 18 as downregulated in distal cholangiocarcinoma samples compared to controls. Immunohistochemical validation revealed thrombospondin-2 to be upregulated in distal cholangiocarcinoma epithelial and stromal compartments. In paired lymph node metastases samples, thrombospondin-2 expression was significantly lower; however, stromal thrombospondin-2 expression was still frequent (72%). Stromal thrombospondin-2 was an independent predictor of poor disease-free survival (HR 3.95, 95% CI 1.09-14.3; P = 0.037). Conclusion: Several proteins without prior association with distal cholangiocarcinoma biology were identified and verified as differentially expressed between distal cholangiocarcinoma and normal bile duct samples. These proteins can be further evaluated to elucidate their biomarker potential and role in distal cholangiocarcinoma carcinogenesis. Stromal thrombospondin-2 is a potential prognostic marker in distal cholangiocarcinoma.
|
|
| 4. |
- Hu, Dingyuan, et al.
(författare)
-
Proteomic analyses identify prognostic biomarkers for pancreatic ductal adenocarcinoma
- 2018
-
Ingår i: Oncotarget. - : Impact Journals, LLC. - 1949-2553. ; 9:11, s. 9789-9807
-
Tidskriftsartikel (refereegranskat)abstract
- Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive malignancy. Here we show that shotgun and targeted protein sequencing can be used to identify potential prognostic biomarkers in formalin-fixed paraffin-embedded specimens from 9 patients with PDAC with "short" survival (< 12 months) and 10 patients with "long" survival ( > 45 months) undergoing surgical resection. A total of 24 and 147 proteins were significantly upregulated [fold change ≥2 or ≤0.5 and P < 0.05; or different detection frequencies (≥5 samples)] in patients with "short" survival (including GLUT1) and "long" survival (including C9orf64, FAM96A, CDH1 and CDH17), respectively. STRING analysis of these proteins indicated a tight protein-protein interaction network centered on TP53. Ingenuity pathway analysis linked proteins representing "activated stroma factors" and "basal tumor factors" to poor prognosis of PDAC. It also highlighted TCF1 and CTNNB1 as possible upstream regulators. Further parallel reaction monitoring verified that seven proteins were upregulated in patients with "short" survival (MMP9, CLIC3, MMP8, PRTN3, P4HA2, THBS1 and FN1), while 18 proteins were upregulated in patients with "long" survival, including EPCAM, LGALS4, VIL1, CLCA1 and TPPP3. Thus, we verified 25 protein biomarker candidates for PDAC prognosis at the tissue level. Furthermore, an activated stroma status and protein-protein interactions with TP53 might be linked to poor prognosis of PDAC.
|
|
| 5. |
- Zhou, Qimin, et al.
(författare)
-
Quantitative proteomics identifies brain acid soluble protein 1 (BASP1) as a prognostic biomarker candidate in pancreatic cancer tissue
- 2019
-
Ingår i: EBioMedicine. - : Elsevier BV. - 2352-3964. ; 43, s. 282-294
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Pancreatic cancer is a heterogenous disease with a poor prognosis. This study aimed to discover and validate prognostic tissue biomarkers in pancreatic cancer using a mass spectrometry (MS) based proteomics approach. Methods: Global protein sequencing of fresh frozen pancreatic cancer and healthy pancreas tissue samples was conducted by MS to discover potential protein biomarkers. Selected candidate proteins were further verified by targeted proteomics using parallel reaction monitoring (PRM). The expression of biomarker candidates was validated by immunohistochemistry in a large tissue microarray (TMA) cohort of 141 patients with resectable pancreatic cancer. Kaplan-Meier and Cox proportional hazard modelling was used to investigate the prognostic utility of candidate protein markers. Findings: In the initial MS-discovery phase, 165 proteins were identified as potential biomarkers. In the subsequent MS-verification phase, a panel of 45 candidate proteins was verified by the development of a PRM assay. Brain acid soluble protein 1 (BASP1) was identified as a new biomarker candidate for pancreatic cancer possessing largely unknown biological and clinical functions and was selected for further analysis. Importantly, bioinformatic analysis indicated that BASP1 interacts with Wilms tumour protein (WT1) in pancreatic cancer. TMA-based immunohistochemistry analysis showed that BASP1 was an independent predictor of prolonged survival (HR 0.468, 95% CI 0.257–0.852, p =.013) and predicted favourable response to adjuvant chemotherapy, whereas WT1 indicated a worsened survival (HR 1.636, 95% CI 1.083–2.473, p =.019) and resistance to chemotherapy. Interaction analysis showed that patients with negative BASP1 and high WT1 expression had the poorest outcome (HR 3.536, 95% CI 1.336–9.362, p =.011). Interpretation: We here describe an MS-based proteomics platform for developing biomarkers for pancreatic cancer. Bioinformatic analysis and clinical data from our study suggest that BASP1 and its putative interaction partner WT1 can be used as biomarkers for predicting outcomes in pancreatic cancer patients.
|
|
