Lorenz Kadletz
Medical University of Vienna
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Featured researches published by Lorenz Kadletz.
Head and Neck-journal for The Sciences and Specialties of The Head and Neck | 2017
Lorenz Kadletz; Stefan Grasl; Matthäus Ch. Grasl; Christos Perisanidis; Boban M. Erovic
The purpose of this study was to evaluate the clinical outcome in patients with benign parotid gland tumors after extracapsular dissection or superficial parotidectomy (SP).
Head and Neck-journal for The Sciences and Specialties of The Head and Neck | 2015
Claudia Lill; Sven Schneider; Rudolf Seemann; Lorenz Kadletz; Klaus Aumayr; Bahil Ghanim; Dietmar Thurnher
Malignant tumors of the salivary glands comprise about 3% to 5% of all head and neck carcinomas. The purpose of our study was to find possible predictive and/or prognostic markers for parotid cancer.
PLOS ONE | 2016
Elisabeth Enzenhofer; Thomas Parzefall; Georg Haymerle; Sven Schneider; Lorenz Kadletz; Gregor Heiduschka; Johannes Pammer; Felicitas Oberndorfer; Fritz Wrba; Benjamin Loader; Matthäus Christoph Grasl; Christos Perisanidis; Boban M. Erovic
Introduction HPV positive patients suffering from head and neck cancer benefit from intensified radiotherapy when applied as a primary as well as an adjuvant treatment strategy. However, HPV negative patients treated with surgery and adjuvant radiotherapy lack validated prognostic biomarkers. It is therefore important to define prognostic biomarkers in this particular patient population. Especially, ´high-risk groups´ need to be defined in order to adapt treatment protocols. Since dysregulation of the sonic hedgehog pathway plays an important role in carcinogenesis, we aimed to assess whether members of the sonic hedgehog-signaling pathway may act as prognostic factors in patients with HPV negative head and neck squamous cell carcinoma. Materials and Methods In this prospective study, pretreatment tumor biopsies of patients with head and neck squamous cell carcinoma were taken during panendoscopy (2005 to 2008). All patients were treated with surgery and postoperative radiotherapy. After assessment of HPV and p16 status, protein expression profiles of the Sonic hedgehog-signaling pathway were determined by immunohistochemistry and tissue microarray analyses in 36 HPV negative tumor biopsies. Expression profiles of Sonic hedgehog, Indian hedgehog, Patched, Smoothened, Gli-1, Gli-2 and Gli-3 were correlated with patients´ clinical data, local-control rate, disease-free as well as overall survival. Data from The Cancer Genome Atlas databank were used for external validation of our results. Results Gli-1 (p = 0.04) and Gli-2 (p = 0.02) overexpression was significantly linked to improved overall survival of HPV negative patients. Gli-2 (p = 0.04) overexpression correlated significantly with prolonged disease-free survival. Cox-multivariate analysis showed that overexpression of Gli-2 correlated independently (HR 0.40, 95% CI 0.16–0.95, p = 0.03) with increased overall survival. Discussion Gli-1 and Gli-2 overexpression represents a substantial prognostic factor for overall and disease-free survival in patients with locally advanced HPV negative head and neck cancer undergoing surgery and postoperative radiotherapy.
Head and Neck-journal for The Sciences and Specialties of The Head and Neck | 2016
Lorenz Kadletz; Johannes Bigenzahn; Dietmar Thurnher; Isabella Stanisz; Boban M. Erovic; Sven Schneider; Rainer Schmid; Rudolf Seemann; Peter Birner; Gregor Heiduschka
Merkel cell carcinoma (MCC) is a rare and aggressive malignancy of the skin. Treatment options for MCC include surgery, radiotherapy, and chemotherapy. The purpose of this study was to assess the expression of Polo‐like kinase 1 (PLK1) in MCC and the role of the inhibitor, BI2536, as a potential therapeutic option in MCC.
Oncology Letters | 2017
Ulana Kotowski; Gregor Heiduschka; Lorenz Kadletz; Tammer Fahim; Rudolf Seemann; Rainer Schmid; Sven Schneider; Andreas Mitterbauer; Dietmar Thurnher
Thymoquinone (TQ) is the main bioactive constituent present in black seed oil (Nigella sativa); it has shown anti-inflammatory and anti-neoplastic effects in various cancer cell types. The aim of the present study was to investigate the effects of TQ on head and neck squamous cell carcinoma (HNSCC) cell lines, on its own and in combination with radiation and cisplatin, respectively. The SCC25 and CAL27 HNSCC cell lines were treated with TQ alone and in combination with cisplatin or radiation, respectively. Proliferation assays and clonogenic assays were performed. Apoptosis was detected by flow cytometry. TQ exhibited dose-dependent cytotoxicity via apoptosis in the investigated cell lines. In combination with cisplatin, TQ resulted in no significant increase in cytotoxicity. Combined with radiation, TQ significantly reduced clonogenic survival compared with each treatment method alone. TQ is a promising agent in the treatment of head and neck cancer due to its anti-proliferative and radiosensitizing properties. However, the combination of TQ with cisplatin showed no therapeutic benefit in vitro.
Head and Neck-journal for The Sciences and Specialties of The Head and Neck | 2017
Elisabeth Enzenhofer; Lorenz Kadletz; Isabella Stanisz; Ulana Kotowski; Rudolf Seemann; Rainer Schmid; Dietmar Thurnher; Gregor Heiduschka
Carcinogenesis is determined by various epigenetic events, such as histone deacetylation. The purpose of this study was to investigate the effect of the new histone deacetylase inhibitor resminostat on head and neck squamous cell carcinoma (HNSCC) cell lines.
Clinical Otolaryngology | 2017
Georg Haymerle; Lorenz Kadletz; Robert Wiebringhaus; B. Golabi; M. Mildner; Dietmar Thurnher; Gregor Heiduschka
Despite the excellent overall survival of 92%‐97% in early glottic cancer, recurrence rates of 13%‐20% have not improved in the last decades. The engulfment and cell motility protein 3 (ELMO3) have been described as prognostic marker in patients with lung cancer. The aim of this study was to investigate the expression of ELMO3 in early laryngeal cancer patients treated with TLM and to evaluate its prognostic significance on clinical outcome.
PLOS ONE | 2018
Julia Thierauf; Stephanie E Weissinger; Johannes A. Veit; Annette Affolter; Natalia K. Laureano; Dirk Beutner; Gregor Heiduschka; Lorenz Kadletz; Moritz F. Meyer; Alexander Quaas; Peter K. Plinkert; Thomas K. Hoffmann; Jochen Hess
Introduction The transcription factor SOX2 has been identified as a lineage survival oncogene in squamous cell carcinoma and copy number gain is a common event in several human malignancies including head and neck cancer. However, the regulation and function of SOX2 during carcinogenesis as well as its prognostic value appears to be highly context dependent. As an example, high SOX2 expression in lung squamous cell carcinoma (SCC) is related to a favorable prognosis, while it is associated with poor outcome in lung adenocarcinoma. More recently, higher SOX2 levels and improved survival was also reported for head and neck SCC (HNSCC), and silencing of SOX2 expression in HNSCC cell lines revealed a mesenchymal-like phenotype with prominent vimentin expression. So far, SOX2 expression and its clinical relevance for other head and neck cancers, such as adenoid cystic carcinoma (HNACC) have not been sufficiently investigated. Material and methods SOX2, vimentin and E-cadherin expression was assessed by immunohistochemical staining on serial sections from formalin fixed and paraffin embedded tissue samples of a patient cohort (n = 45) with primary ACC and correlated with patient and tumor characteristics as well as survival. Results High SOX2 expression was found in 14 (31%) primary tumor specimens and was significantly correlated with a N0 lymph node status (p = 0.04), while low SOX2 expression was correlated with a solid growth pattern (p = 0.031). Of the 45 patients, 27 tumor samples resembled an EMT-like phenotype, as assessed by high vimentin and low E-cadherin levels. However, in HNACC SOX2 levels were neither correlated with vimentin nor with E-cadherin expression, further supporting a context dependent regulation and function of SOX2 in distinct tumor entities. Conclusion The absence of SOX2 was predominantly found in solid HNACC, which are characterized by a more aggressive phenotype in ACC. However, the underlying molecular mechanisms of SOX2 regulation and function in distinct HNACC subgroups remain to be fully elucidated.
Acta Oto-laryngologica | 2017
Lorenz Kadletz; Elisabeth Enzenhofer; Ulana Kotowski; Gabriela Altorjai; Gregor Heiduschka
Abstract Conclusion: On the one hand, AZD5582, an inhibitor of inhibitor of apoptosis family proteins (IAP), leads to cellular growth arrest and induction of apoptosis in head and neck squamous cell carcinoma (HNSCC) cell lines. On the other hand, it is a viable candidate for combination therapy with irradiation. Objectives: The aim and purpose of this study was to evaluate the effects of AZD5582 on HNSCC cell lines. Methods: HNSCC cell lines SCC25, Cal27, and FaDu were used for all cell culture experiments. Proliferation assays were used to assess a potential inhibitory effect of AZD5582 and a combination therapy of the IAP inhibitor and irradiation. Colony forming assays were used to determine long-term effects of a combined treatment. Apoptosis was measured via flow cytometry and wound-healing assays were performed. Results: All three cell lines showed a dose-dependent cytotoxic effect after treatment with AZD5582. It was possible to observe a synergistic and additive effect after short-term treatment of AZD5582 and irradiation in Ca27 and FaDu cells, respectively. All test cell lines showed a significant inhibition of colony formation after combined treatment. Treatment of AZD5582 resulted in apoptosis in SCC25, Cal27, and FaDu cells.
Oral Diseases | 2016
Sven Schneider; Dietmar Thurnher; Lorenz Kadletz; Rudolf Seemann; Markus Brunner; Ulana Kotowski; Rainer Schmid; Claudia Lill; Gregor Heiduschka
OBJECTIVE Prognosis of patients with head and neck squamous cell carcinoma (HNSCC) is still poor. Novel therapeutic approaches are of great interest to improve the effects of radiochemotherapy. We evaluated the effects of tyrosine kinase inhibitor neratinib on HNSCC cell lines CAL27, SCC25 and FaDu as a single agent and in combination with irradiation and chemotherapy. METHODS Effects of neratinib were evaluated in HNSCC cell lines CAL27, SCC25 and FaDu. Effect on cell viability of neratinib and combination with cisplatin and irradiation was measured using CCK-8 assays and clonogenic assays. Western blot analysis was performed to distinguish the effect on epithelial growth factor receptor and HER2 expression. Apoptosis was evaluated by flow cytometry analysis. RESULTS Growth inhibition was achieved in all cell lines, whereas combination of cisplatin and neratinib showed greater inhibition than each agent alone. Apoptosis was induced in all cell lines. Combination of neratinib with irradiation or cisplatin showed significantly increased apoptosis. In clonogenic assays, significant growth inhibition was observed in all investigated cell lines. CONCLUSION Neratinib, as a single agent or in combination with chemo-irradiation, may be a promising treatment option for patients with head and neck cancer.