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Savic D, Steinbichler TB, Ingruber J, Negro G, Aschenbrenner B, Riechelmann H, Ganswindt U, Skvortsov S, Dudás J, Skvortsova II. Erk1/2-Dependent HNSCC Cell Susceptibility to Erastin-Induced Ferroptosis. Cells 2023; 12:336. [PMID: 36672272 PMCID: PMC9856753 DOI: 10.3390/cells12020336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 01/11/2023] [Accepted: 01/12/2023] [Indexed: 01/18/2023] Open
Abstract
Unfavorable clinical outcomes mean that cancer researchers must attempt to develop novel therapeutic strategies to overcome therapeutic resistance in patients with HNSCC. Recently, ferroptosis was shown to be a promising pathway possessing druggable targets, such as xCT (SLC7A11). Unfortunately, little is known about the molecular mechanisms underlying the susceptibility of HNSCC cells to ferroptosis. The goal of this study was to determine whether HNSCC cells with activated Erk1/2 are vulnerable to ferroptosis induction. Our results have shown that xCT (SLC7A11) was overexpressed in malignant tissues obtained from the patients with HNSCC, whereas normal mucosa demonstrated weak expression of the protein. In order to investigate the role of Erk1/2 in the decrease in cell viability caused by erastin, xCT-overexpressing FaDu and SCC25 HNSCC cells were used. The ravoxertinib-dependent inhibition of Erk1/2 signaling led to the decrease in erastin efficacy due to the effect on ROS production and the upregulation of ROS scavengers SOD1 and SOD2, resulting in repressed lipid peroxidation. Therefore, it was concluded that the erastin-dependent activation of ferroptosis seems to be a promising approach which can be further developed as an additional strategy for the treatment of HNSCC. As ferroptosis induction via erastin is strongly dependent on the expression of Erk1/2, this MAP kinase can be considered as a predictor for cancer cells' response to erastin.
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Affiliation(s)
- Dragana Savic
- Laboratory for Experimental and Translational Research on Radiation Oncology (EXTRO-Lab), Department of Therapeutic Radiology and Oncology, Medical University of Innsbruck, A-6020 Innsbruck, Austria
- Tyrolean Cancer Research Institute (TKFI), A-6020 Innsbruck, Austria
| | - Teresa Bernadette Steinbichler
- Department of Otorhinolaryngology and Head and Neck Surgery, Medical University of Innsbruck, A-6020 Innsbruck, Austria
- University Hospital of Tyrol, A-6020 Innsbruck, Austria
| | - Julia Ingruber
- Department of Otorhinolaryngology and Head and Neck Surgery, Medical University of Innsbruck, A-6020 Innsbruck, Austria
- University Hospital of Tyrol, A-6020 Innsbruck, Austria
| | - Giulia Negro
- Laboratory for Experimental and Translational Research on Radiation Oncology (EXTRO-Lab), Department of Therapeutic Radiology and Oncology, Medical University of Innsbruck, A-6020 Innsbruck, Austria
- Tyrolean Cancer Research Institute (TKFI), A-6020 Innsbruck, Austria
| | | | - Herbert Riechelmann
- Department of Otorhinolaryngology and Head and Neck Surgery, Medical University of Innsbruck, A-6020 Innsbruck, Austria
| | - Ute Ganswindt
- Department of Therapeutic Radiology and Oncology, A-6020 Innsbruck, Austria
| | - Sergej Skvortsov
- Laboratory for Experimental and Translational Research on Radiation Oncology (EXTRO-Lab), Department of Therapeutic Radiology and Oncology, Medical University of Innsbruck, A-6020 Innsbruck, Austria
- Tyrolean Cancer Research Institute (TKFI), A-6020 Innsbruck, Austria
- Department of Therapeutic Radiology and Oncology, A-6020 Innsbruck, Austria
| | - József Dudás
- Department of Otorhinolaryngology and Head and Neck Surgery, Medical University of Innsbruck, A-6020 Innsbruck, Austria
| | - Ira-Ida Skvortsova
- Laboratory for Experimental and Translational Research on Radiation Oncology (EXTRO-Lab), Department of Therapeutic Radiology and Oncology, Medical University of Innsbruck, A-6020 Innsbruck, Austria
- Tyrolean Cancer Research Institute (TKFI), A-6020 Innsbruck, Austria
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Ingruber J, Dudás J, Savic D, Schweigl G, Steinbichler TB, Greier MDC, Santer M, Carollo S, Trajanoski Z, Riechelmann H. Corrigendum to "EMT-related transcription factors and protein stabilization mechanisms involvement in cadherin switch of head and neck squamous cell carcinoma" [Exp. Cell Res. 414, 1 May 2022, 113084]. Exp Cell Res 2022; 416:113174. [PMID: 35525075 DOI: 10.1016/j.yexcr.2022.113174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- Julia Ingruber
- Department of Otorhinolaryngology and Head and Neck Surgery, Medical University of Innsbruck, Innsbruck, Austria and University Hospital of Tyrol, Innsbruck, Austria.
| | - József Dudás
- Department of Otorhinolaryngology and Head and Neck Surgery, Medical University of Innsbruck, Innsbruck, Austria and University Hospital of Tyrol, Innsbruck, Austria.
| | - Dragana Savic
- Laboratory for Experimental and Translational Research on Radiation Oncology (EXTRO-Lab), Department of Therapeutic Radiology and Oncology, Medical University of Innsbruck, Austria; Tyrolean Cancer Research Institute, Innsbruck, Austria.
| | - Gabrielle Schweigl
- Department of Otorhinolaryngology and Head and Neck Surgery, Medical University of Innsbruck, Innsbruck, Austria and University Hospital of Tyrol, Innsbruck, Austria.
| | - Teresa Bernadette Steinbichler
- Department of Otorhinolaryngology and Head and Neck Surgery, Medical University of Innsbruck, Innsbruck, Austria and University Hospital of Tyrol, Innsbruck, Austria.
| | - Maria do Carmo Greier
- Department of Otorhinolaryngology and Head and Neck Surgery, Medical University of Innsbruck, Innsbruck, Austria and University Hospital of Tyrol, Innsbruck, Austria.
| | - Matthias Santer
- Department of Otorhinolaryngology and Head and Neck Surgery, Medical University of Innsbruck, Innsbruck, Austria and University Hospital of Tyrol, Innsbruck, Austria.
| | - Sandro Carollo
- Institute of Bioinformatics Medical University of Innsbruck, Austria.
| | - Zlatko Trajanoski
- Institute of Bioinformatics Medical University of Innsbruck, Austria.
| | - Herbert Riechelmann
- Department of Otorhinolaryngology and Head and Neck Surgery, Medical University of Innsbruck, Innsbruck, Austria and University Hospital of Tyrol, Innsbruck, Austria.
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Ingruber J, Dudás J, Savic D, Schweigl G, Steinbichler TB, Greier MDC, Santer M, Carollo S, Trajanoski Z, Riechelmann H. EMT-related transcription factors and protein stabilization mechanisms involvement in cadherin switch of head and neck squamous cell carcinoma. Exp Cell Res 2022; 414:113084. [DOI: 10.1016/j.yexcr.2022.113084] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 02/03/2022] [Accepted: 02/22/2022] [Indexed: 12/16/2022]
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Ingruber J, Savic D, Steinbichler TB, Sprung S, Fleischer F, Glueckert R, Schweigl G, Skvortsova II, Riechelmann H, Dudás J. KLF4, Slug and EMT in Head and Neck Squamous Cell Carcinoma. Cells 2021; 10:cells10030539. [PMID: 33802627 PMCID: PMC7998447 DOI: 10.3390/cells10030539] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 02/19/2021] [Accepted: 02/27/2021] [Indexed: 02/07/2023] Open
Abstract
Epithelial to mesenchymal transition (EMT) is clinically relevant in head and neck squamous cell carcinoma (HNSCC). We hypothesized that EMT-transcription factors (EMT-TFs) and an anti-EMT factor, Krüppel-like-factor-4 (KLF4) regulate EMT in HNSCC. Ten control mucosa and 37 HNSCC tissue samples and three HNSCC cell lines were included for investigation of EMT-TFs, KLF4 and vimentin at mRNA and protein levels. Slug gene expression was significantly higher, whereas, KLF4 gene expression was significantly lower in HNSCC than in normal mucosa. In the majority of HNSCC samples, there was a significant negative correlation between KLF4 and Slug gene expression. Slug gene expression was significantly higher in human papilloma virus (HPV) negative HNSCC, and in tumor samples with irregular p53 gene sequence. Transforming-growth-factor-beta-1 (TGF- β1) contributed to downregulation of KLF4 and upregulation of Slug. Two possible regulatory pathways could be suggested: (1) EMT-factors induced pathway, where TGF-β1 induced Slug together with vimentin, and KLF4 was down regulated at the same time; (2) p53 mutations contributed to upregulation and stabilization of Slug, where also KLF4 could co-exist with EMT-TFs.
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Affiliation(s)
- Julia Ingruber
- Department of Otorhinolaryngology and Head and Neck Surgery, Medical University of Innsbruck, University Hospital of Tyrol, A-6020 Innsbruck, Austria; (J.I.); (T.B.S.); (F.F.); (R.G.); (G.S.); (H.R.)
| | - Dragana Savic
- Laboratory for Experimental and Translational Research on Radiation Oncology (EXTRO-Lab), Department of Therapeutic Radiology and Oncology, Medical University of Innsbruck, A-6020 Innsbruck, Austria; (D.S.); (I.-I.S.)
- Tyrolean Cancer Research Institute, A-6020 Innsbruck, Austria
| | - Teresa Bernadette Steinbichler
- Department of Otorhinolaryngology and Head and Neck Surgery, Medical University of Innsbruck, University Hospital of Tyrol, A-6020 Innsbruck, Austria; (J.I.); (T.B.S.); (F.F.); (R.G.); (G.S.); (H.R.)
| | - Susanne Sprung
- Department of Pathology, Medical University of Innsbruck, A-6020 Innsbruck, Austria;
| | - Felix Fleischer
- Department of Otorhinolaryngology and Head and Neck Surgery, Medical University of Innsbruck, University Hospital of Tyrol, A-6020 Innsbruck, Austria; (J.I.); (T.B.S.); (F.F.); (R.G.); (G.S.); (H.R.)
- Department of Restorative and Operative Dentistry, Medical University of Innsbruck, A-6020 Innsbruck, Austria
| | - Rudolf Glueckert
- Department of Otorhinolaryngology and Head and Neck Surgery, Medical University of Innsbruck, University Hospital of Tyrol, A-6020 Innsbruck, Austria; (J.I.); (T.B.S.); (F.F.); (R.G.); (G.S.); (H.R.)
| | - Gabriele Schweigl
- Department of Otorhinolaryngology and Head and Neck Surgery, Medical University of Innsbruck, University Hospital of Tyrol, A-6020 Innsbruck, Austria; (J.I.); (T.B.S.); (F.F.); (R.G.); (G.S.); (H.R.)
| | - Ira-Ida Skvortsova
- Laboratory for Experimental and Translational Research on Radiation Oncology (EXTRO-Lab), Department of Therapeutic Radiology and Oncology, Medical University of Innsbruck, A-6020 Innsbruck, Austria; (D.S.); (I.-I.S.)
- Tyrolean Cancer Research Institute, A-6020 Innsbruck, Austria
| | - Herbert Riechelmann
- Department of Otorhinolaryngology and Head and Neck Surgery, Medical University of Innsbruck, University Hospital of Tyrol, A-6020 Innsbruck, Austria; (J.I.); (T.B.S.); (F.F.); (R.G.); (G.S.); (H.R.)
| | - József Dudás
- Department of Otorhinolaryngology and Head and Neck Surgery, Medical University of Innsbruck, University Hospital of Tyrol, A-6020 Innsbruck, Austria; (J.I.); (T.B.S.); (F.F.); (R.G.); (G.S.); (H.R.)
- Correspondence: ; Tel.: +43-512-5048-2475
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Giotakis AI, Dudas J, Glueckert R, Dejaco D, Ingruber J, Fleischer F, Innerhofer V, Pinggera L, Bektic-Tadic L, Gabriel SAM, Riechelmann H. Characterization of epithelial cells, connective tissue cells and immune cells in human upper airway mucosa by immunofluorescence multichannel image cytometry: a pilot study. Histochem Cell Biol 2021; 155:405-421. [PMID: 33251550 PMCID: PMC8021535 DOI: 10.1007/s00418-020-01945-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/10/2020] [Indexed: 12/30/2022]
Abstract
Epithelial, connective tissue and immune cells contribute in various ways to the pathophysiology of chronic rhinosinusitis (CRS). However, data of their distribution in upper airway mucosa are sparse. We aimed to provide quantitative, purely informative data on the distribution of these cell lineages and their coexpression patterns, which might help identifying, e.g., cells in the epithelium undergoing through epithelial-mesenchymal transition (EMT). For this purpose, we used immunofluorescence multichannel image cytometry (IMIC). We examined fixed paraffin-embedded tissue samples (FFPE) of six patients with chronic rhinosinusitis (CRS) and of three patients without CRS (controls). The direct-conjugated antibodies pancytokeratin, vimentin and CD45/CD18 were used for coexpression analysis in epithelial layer and lamina propria. Image acquisition and analysis were performed with TissueFAXS and StrataQuest, respectively. To distinguish positive from negative expression, a ratio between cell-specific immunostaining intensity and background was developed. Isotype controls were used as negative controls. Per patient, a 4.5-mm2 tissue area was scanned and a median of 14,875 cells was recognized. The most common cell types were cytokeratin-single-positive (26%), vimentin-single-positive (13%) and CD45/CD18-single-positive with CD45/CD18-vimentin-double-positive cells (29%). In the patients with CRS, CD45/CD18-single-positive cells were 3-6 times higher compared to the control patients. In the epithelial layer, cytokeratin-vimentin-double-positive EMT cells were observed 3-5 times higher in the patients with CRS than in the control patients. This study provided quantitative data for the distribution of crucial cell types in CRS. Future studies may focus on the distribution and coexpression patterns of different immune cells in CRS or even cancer tissue.
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Affiliation(s)
- Aris I Giotakis
- Department of Otorhinolaryngology, Medical University of Innsbruck, Innsbruck, Austria.
| | - Jozsef Dudas
- Department of Otorhinolaryngology, Medical University of Innsbruck, Innsbruck, Austria
| | - Rudolf Glueckert
- University Clinics Innsbruck, Tirol Kliniken, Anichstrasse 35, 6020, Innsbruck, Austria
| | - Daniel Dejaco
- Department of Otorhinolaryngology, Medical University of Innsbruck, Innsbruck, Austria
| | - Julia Ingruber
- Department of Otorhinolaryngology, Medical University of Innsbruck, Innsbruck, Austria
| | - Felix Fleischer
- Department of Otorhinolaryngology, Medical University of Innsbruck, Innsbruck, Austria
| | - Veronika Innerhofer
- Department of Otorhinolaryngology, Medical University of Innsbruck, Innsbruck, Austria
| | - Leyla Pinggera
- Department of Otorhinolaryngology, Medical University of Innsbruck, Innsbruck, Austria
| | - Ljilja Bektic-Tadic
- Department of Otorhinolaryngology, Medical University of Innsbruck, Innsbruck, Austria
| | - Sarah A M Gabriel
- Department of Otorhinolaryngology, Medical University of Innsbruck, Innsbruck, Austria
| | - Herbert Riechelmann
- Department of Otorhinolaryngology, Medical University of Innsbruck, Innsbruck, Austria
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Lyskjaer I, Lindsay D, Tirabosco R, Steele CD, Lombard P, Strobl AC, Rocha AM, Davies C, Ye H, Bekers E, Ingruber J, Lechner M, Amary F, Pillay N, Flanagan AM. H3K27me3 expression and methylation status in histological variants of malignant peripheral nerve sheath tumours. J Pathol 2020; 252:151-164. [PMID: 32666581 PMCID: PMC8432159 DOI: 10.1002/path.5507] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 06/23/2020] [Accepted: 07/06/2020] [Indexed: 12/17/2022]
Abstract
Diagnosing MPNST can be challenging, but genetic alterations recently identified in polycomb repressive complex 2 (PRC2) core component genes, EED and SUZ12, resulting in global loss of the histone 3 lysine 27 trimethylation (H3K27me3) epigenetic mark, represent drivers of malignancy and a valuable diagnostic tool. However, the reported loss of H3K27me3 expression ranges from 35% to 84%. We show that advances in molecular pathology now allow many MPNST mimics to be classified confidently. We confirm that MPNSTs harbouring mutations in PRC2 core components are associated with loss of H3K27me3 expression; whole‐genome doubling was detected in 68%, and SSTR2 was amplified in 32% of MPNSTs. We demonstrate that loss of H3K27me3 expression occurs overall in 38% of MPNSTs, but is lost in 76% of histologically classical cases, whereas loss was detected in only 23% cases with heterologous elements and 14% where the diagnosis could not be provided on morphology alone. H3K27me3 loss is rarely seen in other high‐grade sarcomas and was not found to be associated with an inferior outcome in MPNST. We show that DNA methylation profiling distinguishes MPNST from its histological mimics, was unrelated to anatomical site, and formed two main clusters, MeGroups 4 and 5. MeGroup 4 represents classical MPNSTs lacking H3K27me3 expression in the majority of cases, whereas MeGroup 5 comprises MPNSTs exhibiting non‐classical histology and expressing H3K27me3 and cluster with undifferentiated sarcomas. The two MeGroups are distinguished by differentially methylated PRC2‐associated genes, the majority of which are hypermethylated in the promoter regions in MeGroup 4, indicating that the PRC2 target genes are not expressed in these tumours. The methylation profiles of MPNSTs with retention of H3K27me3 in MeGroups 4 and 5 are independent of mutations in PRC2 core components and the driver(s) in these groups remain to be identified. Our results open new avenues of investigation. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.
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Affiliation(s)
- Iben Lyskjaer
- Research Department of Pathology, University College London, London, UK
| | - Daniel Lindsay
- Research Department of Pathology, University College London, London, UK.,Department of Histopathology, Royal National Orthopaedic Hospital, Stanmore, UK
| | - Roberto Tirabosco
- Department of Histopathology, Royal National Orthopaedic Hospital, Stanmore, UK
| | | | - Patrick Lombard
- Research Department of Pathology, University College London, London, UK
| | | | - Ana M Rocha
- Department of Histopathology, Royal National Orthopaedic Hospital, Stanmore, UK
| | - Christopher Davies
- Department of Histopathology, Royal National Orthopaedic Hospital, Stanmore, UK
| | - Hongtao Ye
- Department of Histopathology, Royal National Orthopaedic Hospital, Stanmore, UK
| | - Elise Bekers
- Department of Pathology, Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Julia Ingruber
- Department of Otorhinolaryngology, Medical University of Innsbruck, Innsbruck, Austria
| | - Matt Lechner
- UCL Cancer Institute, University College London, London, UK
| | - Fernanda Amary
- Research Department of Pathology, University College London, London, UK.,Department of Histopathology, Royal National Orthopaedic Hospital, Stanmore, UK
| | - Nischalan Pillay
- Research Department of Pathology, University College London, London, UK.,Department of Histopathology, Royal National Orthopaedic Hospital, Stanmore, UK
| | - Adrienne M Flanagan
- Research Department of Pathology, University College London, London, UK.,Department of Histopathology, Royal National Orthopaedic Hospital, Stanmore, UK
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Steinbichler TB, Dudas J, Ingruber J, Glueckert R, Sprung S, Fleischer F, Cidlinsky N, Dejaco D, Kofler B, Giotakis AI, Skvortsova II, Riechelmann H. Slug Is A Surrogate Marker of Epithelial to Mesenchymal Transition (EMT) in Head and Neck Cancer. J Clin Med 2020; 9:jcm9072061. [PMID: 32630033 PMCID: PMC7408865 DOI: 10.3390/jcm9072061] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Revised: 06/22/2020] [Accepted: 06/23/2020] [Indexed: 12/12/2022] Open
Abstract
Background: Epithelial to mesenchymal transition (EMT) promotes therapy resistance in head and neck cancer (HNC) cells. In this study, EMT was quantified in HNC tumor samples by the cellular co-localization of cytokeratin/vimentin, E-cadherin/β-catenin and by Slug expression. Methods: Tissue samples from HNC patients were stained with antibody pairs against cytokeratin/vimentin and E-cadherin/β-catenin. Epithelial–mesenchymal co-localization was quantified using immunofluorescence multichannel image cytometry. Double positivity was confirmed using confocal microscopy. Slug was semi-quantified by 2 specialists and quantified by bright field image cytometry. Results: Tumor samples of 102 patients were investigated. A loss of E-cadherin positive cells (56.9 ± 2.6% vs. 97.9 ± 1.0%; p < 0.0001) and E-cadherin/β-catenin double positive cells (15.4 ± 5.7% vs. 85.4 ± 1.2%; p < 0.0001) was observed in tumor samples. The percentage of Slug positive cells was increased in tumor samples (12.1 ± 3.6% vs. 3.2 ± 2.6%; p = 0.001). Ordinal Slug scores judged by two specialists closely correlated with percentage of Slug-positive cells (Spearman’s rho = 0.81; p < 0.001). Slug score correlated negatively with the percentage of E-cadherin positive cells (r = 0.4; p = 0.006), the percentage of E-cadherin/β-catenin positive cells (r = 0.5; p = 0.001) and positively with cytokeratin/vimentin positive cells (r = 0.4, p = 0.003). Conclusion: EMT can be assessed in HNC tumor probes by cytokeratin/vimentin co-expression and loss of E-cadherin/β-catenin co-expression. Slug score provides a convenient surrogate marker for EMT.
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Affiliation(s)
- T. B. Steinbichler
- Department for Otorhinolaryngology, Head and Neck surgery, Medical University of Innsbruck, 6020 Innsbruck, Austria; (J.D.); (J.I.); (R.G.); (F.F.); (N.C.); (D.D.); (B.K.); (A.I.G.); (H.R.)
- Correspondence: ; Tel.: +43-512-504-23142
| | - J. Dudas
- Department for Otorhinolaryngology, Head and Neck surgery, Medical University of Innsbruck, 6020 Innsbruck, Austria; (J.D.); (J.I.); (R.G.); (F.F.); (N.C.); (D.D.); (B.K.); (A.I.G.); (H.R.)
| | - J. Ingruber
- Department for Otorhinolaryngology, Head and Neck surgery, Medical University of Innsbruck, 6020 Innsbruck, Austria; (J.D.); (J.I.); (R.G.); (F.F.); (N.C.); (D.D.); (B.K.); (A.I.G.); (H.R.)
| | - R. Glueckert
- Department for Otorhinolaryngology, Head and Neck surgery, Medical University of Innsbruck, 6020 Innsbruck, Austria; (J.D.); (J.I.); (R.G.); (F.F.); (N.C.); (D.D.); (B.K.); (A.I.G.); (H.R.)
| | - S. Sprung
- Institute of Pathology, Neuropathology and Molecular Pathology, Medical University of Innsbruck, 6020 Innsbruck, Austria;
| | - F. Fleischer
- Department for Otorhinolaryngology, Head and Neck surgery, Medical University of Innsbruck, 6020 Innsbruck, Austria; (J.D.); (J.I.); (R.G.); (F.F.); (N.C.); (D.D.); (B.K.); (A.I.G.); (H.R.)
| | - N. Cidlinsky
- Department for Otorhinolaryngology, Head and Neck surgery, Medical University of Innsbruck, 6020 Innsbruck, Austria; (J.D.); (J.I.); (R.G.); (F.F.); (N.C.); (D.D.); (B.K.); (A.I.G.); (H.R.)
| | - D. Dejaco
- Department for Otorhinolaryngology, Head and Neck surgery, Medical University of Innsbruck, 6020 Innsbruck, Austria; (J.D.); (J.I.); (R.G.); (F.F.); (N.C.); (D.D.); (B.K.); (A.I.G.); (H.R.)
| | - B. Kofler
- Department for Otorhinolaryngology, Head and Neck surgery, Medical University of Innsbruck, 6020 Innsbruck, Austria; (J.D.); (J.I.); (R.G.); (F.F.); (N.C.); (D.D.); (B.K.); (A.I.G.); (H.R.)
| | - A. I. Giotakis
- Department for Otorhinolaryngology, Head and Neck surgery, Medical University of Innsbruck, 6020 Innsbruck, Austria; (J.D.); (J.I.); (R.G.); (F.F.); (N.C.); (D.D.); (B.K.); (A.I.G.); (H.R.)
| | - I. I. Skvortsova
- Department of Therapeutic Radiology and Oncology, Medical University of Innsbruck; 6020 Innsbruck, Austria;
- Tyrolean Cancer Research Institute, 6020 Innsbruck, Austria
| | - H. Riechelmann
- Department for Otorhinolaryngology, Head and Neck surgery, Medical University of Innsbruck, 6020 Innsbruck, Austria; (J.D.); (J.I.); (R.G.); (F.F.); (N.C.); (D.D.); (B.K.); (A.I.G.); (H.R.)
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Neuner G, Monitzer K, Kaplenig D, Ingruber J. Frost Survival Mechanism of Vegetative Buds in Temperate Trees: Deep Supercooling and Extraorgan Freezing vs. Ice Tolerance. Front Plant Sci 2019; 10:537. [PMID: 31143193 PMCID: PMC6521125 DOI: 10.3389/fpls.2019.00537] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 04/08/2019] [Indexed: 05/08/2023]
Abstract
In temperate climates, overwintering buds of trees are often less cold hardy than adjoining stem tissues or evergreen leaves. However, data are scarce regarding the freezing resistance (FR) of buds and the underlying functional frost survival mechanism that in case of supercooling can restrict the geographic distribution. Twigs of 37 temperate woody species were sampled in midwinter 2016 in the Austrian Inn valley. After assessment of FR, infrared-video-thermography and cryo-microscopy were used to study the freezing pattern in and around overwintering vegetative buds. Only in four species, after controlled ice nucleation in the stem (-1.6 ± 0.9°C) ice was observed to immediately invade the bud. These buds tolerated extracellular ice and were the most freezing resistant (-61.8°C mean LT50). In all other species (33), the buds remained supercooled and free of ice, despite a frozen stem. A structural ice barrier prevents ice penetration. Extraorgan ice masses grew in the stem and scales but in 50% of the species between premature supercooled leaves. Two types of supercooled buds were observed: in temporary supercooling buds (14 species) ice spontaneously nucleated at -20.5 ± 4,6°C. This freezing process appeared to be intracellular as it matched the bud killing temperature (-22.8°C mean LT50). This response rendered temporarily supercooled buds as least cold hardy. In 19 species, the buds remained persistently supercooled down to below the killing temperature without indication for the cause of damage. Although having a moderate midwinter FR of -31.6°C (LT50), some species within this group attained a FR similar to ice tolerant buds. The present study represents the first comprehensive overview of frost survival mechanisms of vegetative buds of temperate trees. Except for four species that were ice tolerant, the majority of buds survive in a supercooled state, remaining free of ice. In 50% of species, extraorgan ice masses harmlessly grew between premature supercooled leaves. Despite exposure to the same environmental demand, midwinter FR of buds varied intra-specifically between -17.0 and -90.0°C. Particularly, species, whose buds are killed after temporary supercooling, have a lower maximum FR, which limits their geographic distribution.
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Affiliation(s)
- Gilbert Neuner
- Unit Functional Plant Biology, Department of Botany, University of Innsbruck, Innsbruck, Austria
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