Johannes Haybaeck

Prof. Dr. Johannes Haybaeck


Research Focus & Metrics

Academic Career Length

4Years (2023-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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16 August 2023 in Biomolecules
Verified
Journal Article
Open access
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TDTatiana Soultana Driva
Tatiana Soultana Driva
CSChristoph Schatz
Christoph Schatz
JHJohannes Haybaeck
Johannes Haybaeck
Ovarian clear cell (OCCC) and endometrioid (EnOC) carcinomas are often subsumed under the umbrella term “endometriosis-associated ovarian cancer” (EAOC), since they frequently arise from ectopic endometrium settled in the ovaries. The phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway is known to be aberrantly activated both in endometriosis and EAOC; however, its role in the progression of endometriosis to ovarian cancer remains unclear. In fact, cancer-associated alterations in the mTOR pathway may be found in normal uterine epithelium, likely acting as a first step towards ovarian cancer, through the intermediary stage of endometriosis. This review aims to summarize the current knowledge regarding mTOR signaling dysregulation in the uterine endometrium, endometriosis, and EAOC while focusing on the interconnections between the PI3K/AKT/mTOR pathway and other signaling molecules that give rise to synergistic molecular mechanisms triggering ovarian cancer development in the presence of endometriosis.

9 November 2023 in Cancers
Verified
Journal Article
Open access
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ACAnna M. Cyran
Anna M. Cyran
FKFlorian Kleinegger
Florian Kleinegger
Norbert NassNorbert Nass
Norbert Nass
MNMichael Naumann
Michael Naumann
JHJohannes Haybaeck
Johannes Haybaeck
Dr. Christoph ArensDr. Christoph Arens
Dr. Christoph Arens
Drug resistance is a common cause of therapy failure in head and neck squamous cell carcinoma (HNSCC). One approach to tackling it is by targeting fundamental cellular processes, such as translation. The eukaryotic translation initiation factor 2α (EIF2α) is a key player in canonical translation initiation and integrates diverse stress signals; when phosphorylated, it curbs global protein synthesis. This study evaluates EIF2α expression and phosphorylation in HNSCC. A small-molecule inhibitor of EIF2α dephosphorylation, salubrinal, was tested in vitro, followed by viability assays, flow cytometry, and immunoblot analyses. Patient-derived 3D tumor spheres (PD3DS) were cultured with salubrinal and their viability assessed. Lastly, salubrinal was evaluated with standard-of-care chemotherapeutics. Our analysis of RNA and proteomics data shows elevated EIF2α expression in HNSCC. Immunohistochemical staining reveals increasing EIF2α abundance from premalignant lesions to invasive and metastatic carcinoma. In immunoblots from intraoperative samples, EIF2α expression and steady-state phosphorylation are higher in HNSCC than in neighboring normal tissue. Inhibition of EIF2α dephosphorylation decreases HNSCC cell viability and clonogenic survival and impairs the G1/S transition. Salubrinal also decreases the viability of PD3DS and acts synergistically with cisplatin, 5-fluorouracil, bleomycin, and proteasome inhibitors. Our results indicate that pharmacological inhibition of EIF2α dephosphorylation is a potential therapeutic strategy for HNSCC.

31 October 2023 in Journal of Neuro-Oncology
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Journal Article
Open access
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SKStefanie Krassnig
Stefanie Krassnig
SLStefan L. Leber
Stefan L. Leber
AOAndrea Orthmann
Andrea Orthmann
NGNicole Golob-Schwarzl
Nicole Golob-Schwarzl
HHHeinrich Johann Huber
Heinrich Johann Huber
JHJohannes Haybaeck
Johannes Haybaeck
Purpose: Since glioma therapy is currently still limited until today, new treatment options for this heterogeneous group of tumours are of great interest. Eukaryotic initiation factors (eIFs) are altered in various cancer entities, including gliomas. The purpose of our study was to evaluate the potential of eIFs as novel targets in glioma treatment. Methods: We evaluated eIF protein expression and regulation in 22 glioblastoma patient-derived xenografts (GBM PDX) after treatment with established cytostatics and with regards to mutation profile analyses of GBM PDX. Results: We observed decreased expression of several eIFs upon temozolomide (TMZ) treatment independent from the phosphatidylinositol 3-kinase (PI3K)/ AKT/ mammalian target of the rapamycin (mTOR) signalling pathway. These effects of TMZ treatment were not present in TMZ-resistant PDX. Combination therapy of regorafenib and TMZ re- established the eIF/AKT/mTOR axis. Conclusion: Our study provides novel insights into chemotherapeutic effects on eIF regulation in gliomas and suggests that eIFs are interesting candidates for future research to improve glioma therapy.

15 April 2024 in Microorganisms
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Journal Article
Open access
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CSChristoph Schatz
Christoph Schatz
Ludwig KnablLudwig Knabl
Ludwig Knabl
HLHYE KYUNG LEE
HYE KYUNG LEE
Rita SeeböckRita Seeböck
Rita Seeböck
Dorothee Von LaerDorothee Von Laer
Dorothee Von Laer
JHJohannes Haybaeck
Johannes Haybaeck
The global dissemination of SARS-CoV-2 resulted in the emergence of several variants, including Alpha, Alpha + E484K, Beta, and Omicron. Our research integrated the study of eukaryotic translation factors and fundamental components in general protein synthesis with the analysis of SARS-CoV-2 variants and vaccination status. Utilizing statistical methods, we successfully differentiated between variants in infected individuals and, to a lesser extent, between vaccinated and non-vaccinated infected individuals, relying on the expression profiles of translation factors. Additionally, our investigation identified common causal relationships among the translation factors, shedding light on the interplay between SARS-CoV-2 variants and the host’s translation machinery.

21 November 2023 in Die Pathologie
Verified
Journal Article
Closed access
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CSChristoph Schatz
Christoph Schatz
AQAdelina Adelina Qerimi
Adelina Adelina Qerimi
JHJohannes Haybaeck
Johannes Haybaeck