Time filter

Source Type

Schrader C.H.,University of Heidelberg | Kolb M.,University of Heidelberg | Zaoui K.,University of Heidelberg | Flechtenmacher C.,University of Heidelberg | And 7 more authors.
Molecular Cancer

Background: Dysregulated expression of Kallikrein-related peptidase 6 (KLK6) is a common feature for many human malignancies and numerous studies evaluated KLK6 as a promising biomarker for early diagnosis or unfavorable prognosis. However, the expression of KLK6 in carcinomas derived from mucosal epithelia, including head and neck squamous cell carcinoma (HNSCC), and its mode of action has not been addressed so far. Methods: Stable clones of human mucosal tumor cell lines were generated with shRNA-mediated silencing or ectopic overexpression to characterize the impact of KLK6 on tumor relevant processes in vitro. Tissue microarrays with primary HNSCC samples from a retrospective patient cohort (n=162) were stained by immunohistochemistry and the correlation between KLK6 staining and survival was addressed by univariate Kaplan-Meier and multivariate Cox proportional hazard model analysis. Results: KLK6 expression was detected in head and neck tumor cell lines (FaDu, Cal27 and SCC25), but not in HeLa cervix carcinoma cells. Silencing in FaDu cells and ectopic expression in HeLa cells unraveled an inhibitory function of KLK6 on tumor cell proliferation and mobility. FaDu clones with silenced KLK6 expression displayed molecular features resembling epithelial-to-mesenchymal transition, nuclear β-catenin accumulation and higher resistance against irradiation. Low KLK6 protein expression in primary tumors from oropharyngeal and laryngeal SCC patients was significantly correlated with poor progression-free (p=0.001) and overall survival (p<0.0005), and served as an independent risk factor for unfavorable clinical outcome. Conclusions: In summary, detection of low KLK6 expression in primary tumors represents a promising tool to stratify HNSCC patients with high risk for treatment failure. These patients might benefit from restoration of KLK6 expression or pharmacological targeting of signaling pathways implicated in EMT. © 2015 Schrader et al.; licensee BioMed Central. Source

Bayo P.,University of Heidelberg | Bayo P.,German Cancer Research Center | Jou A.,University of Heidelberg | Jou A.,German Cancer Research Center | And 18 more authors.
Molecular Oncology

Recurrent gain on chromosome 3q26 encompassing the gene locus for the transcription factor SOX2 is a frequent event in human squamous cell carcinoma, including head and neck squamous cell carcinoma (HNSCC). Numerous studies demonstrated that SOX2 expression and function is related to distinct aspects of tumor cell pathophysiology. However, the underlying molecular mechanisms are not well understood, and the correlation between SOX2 expression and clinical outcome revealed conflicting data. Transcriptional profiling after silencing of SOX2 expression in a HNSCC cell line identified a set of up-regulated genes related to cell motility (e.g. VIM, FN1, CDH2). The inverse regulation of SOX2 and aforementioned genes was validated in 18 independent HNSCC cell lines from different anatomical sites. The inhibition of cell migration and invasion by SOX2 was confirmed by constant or conditional gene silencing and accelerated motility of HNSCC cells after SOX2 silencing was partially reverted by down-regulation of vimentin. In a retrospective study, SOX2 expression was determined by immunohistochemical staining on tissue microarrays containing primary tumor specimens of two independent HNSCC patient cohorts. Low SOX2 expression was found in 19.3% and 44.9% of primary tumor specimens, respectively. Univariate analysis demonstrated a statistically significant correlation between low SOX2 protein levels and reduced progression-free survival (Cohort I 51 vs. 16 months; Cohort II 33 vs. 12 months) and overall survival (Cohort I 150 vs. 37 months; Cohort II 33 vs. 16 months). Multivariate Cox proportional hazard model analysis confirmed that low SOX2 expression serves as an independent prognostic marker for HNSCC patients. We conclude that SOX2 inhibits tumor cell motility in HNSCC cells and that low SOX2 expression serves as a prognosticator to identify HNSCC patients at high risk for treatment failure. © 2015 Federation of European Biochemical Societies. Source

Freudlsperger C.,University of Heidelberg | Horn D.,University of Heidelberg | Weissfuss S.,University of Heidelberg | Weichert W.,University of Heidelberg | And 11 more authors.
International Journal of Cancer

Head and neck squamous cell carcinoma (HNSCC) is frequently characterized by high resistance to radiotherapy, which critically depends on both altered signaling pathways within tumor cells and their dynamic interaction with the tumor microenvironment. This study evaluated the prognostic value of the phosphorylation status of AKT on Ser473 and Thr308 for the clinical outcome of patients with advanced HNSCC on radiotherapy. Furthermore, we investigated the impact of AKT(Ser473) phosphorylation [p-AKT(Ser473)] in the context of radioresistance using ex vivo tissue cultures that resemble the complex tissue architecture and paracrine interaction with the tumor microenvironment. In a cohort of 120 patients with advanced HNSCC, who were treated with primary or adjuvant radiotherapy, a significant association was found between relative p-AKT(Ser473) levels and overall survival (p-=-0.006) as well as progression-free survival (p-=-0.021), while no significant correlation was revealed for relative p-AKT(Thr308) levels. In ex vivo tissue cultures p-AKT(Ser473) levels were increased upon irradiation and treatment with the PI3K inhibitor LY294002 inhibited both basal and irradiation induced AKT(Ser473) phosphorylation. Strikingly, pretreatment with LY294002 sensitized tissue cultures derived from primary and recurrent tumors to radiotherapy as determined by impaired tumor cell proliferation and enhanced DNA damage. In conclusion, phosphorylation status of AKT(Ser473) in tumor specimens serves as a novel biomarker to identify patients with advanced HNSCC at high risk for treatment failure following radiotherapy, and our data from ex vivo tissue cultures support the assumption that pharmacological inhibition of AKT(Ser473) phosphorylation might circumvent radioresistance to improve efficiency and reduce toxicity of current treatment modalities. What's new? Patients with head and neck squamous cell cancers often develop resistance to radiotherapy. To figure out how, these authors investigated AKT phosphorylation in the tumor cells. AKT kinase boosts cell proliferation when it is activated by phosphorylation at two possible sites. Could the location of phosphorylation predict whether the tumor will develop resistance? These results suggest it could. The authors show that patients with more phosphorylation at serine 473 had worse survival; furthermore, they showed that reducing phosphorylation at this site increased cancer cells' vulnerability to irradiation. Phosphorylation at the other site, threonine 308, did not affect survival. © 2014 UICC. Source

Hildenbrand M.,German Cancer Research Center | Rhiemeier V.,German Cancer Research Center | Hartenstein B.,German Cancer Research Center | Lahrmann B.,University of Heidelberg | And 5 more authors.
Journal of Investigative Dermatology

Recently, we identified an AP-1-dependent target gene in 12-O-tetradecanoylphorbol-13-acetate (TPA)-treated mouse back skin, which encodes a retroviral-like aspartic proteinase (Taps/Asprv1). Taps expression was detected almost exclusively in stratified epithelia of mouse embryos and adult tissues, and enhanced protein levels were present in several non-neoplastic human skin disorders, implicating a crucial role for differentiation and homeostasis of multilayered epithelia. Here, we generated a mouse model in which Taps transgene expression is under the control of the human ubiquitin C promoter (UBC-Taps). Although no obvious phenotype was observed in normal skin development and homeostasis, these mice showed a significant delay in cutaneous wound closure compared with control animals. Shortly after re-epithelialization, we found an increase in keratinocytes in the stratum granulosum, which express Filaggrin, a late differentiation marker. A hypergranulosum-like phenotype with increased numbers of Filaggrin-positive keratinocytes was also observed in UBC-Taps mice after administration of TPA. In summary, these data show that aberrant Taps expression causes impaired skin regeneration and skin remodeling after cutaneous injury and chemically induced hyperplasia. © 2010 The Society for Investigative Dermatology. Source

Halec G.,German Cancer Research Center | Alemany L.,Catalan Institute of Nanoscience and Nanotechnology | Alemany L.,CIBER ISCIII | Lloveras B.,Catalan Institute of Nanoscience and Nanotechnology | And 18 more authors.
Journal of Pathology

Eight HPV types (HPV26, 53, 66, 67, 68, 70, 73 and 82) that are phylogenetically closely related to 12 WHO-defined high-risk (HR) HPV have been rarely but consistently identified as single HPV infections in about 3% of cervical cancer (CxCa) tissues. Due to lack of biological data, these types are referred to as probable/possible (p) HR-HPV. To analyse their biological activity in direct comparison to HR-HPV types, we selected 55 formalin-fixed, paraffin-embedded (FFPE) CxCa tissues harbouring single pHR-HPV infections (2-13 cases per type) and 266 tissues harbouring single HR-HPV (7-40 cases per type) from a worldwide, retrospective, cross-sectional study. Single HPV infection was verified by two genotyping methods. Presence of type-specific spliced E6∗I mRNA transcripts and expression of cellular proteins indicative of HPV transformation were assessed in all cases. In 55 CxCa tissues with pHR-HPV, E6∗I mRNA expression was 100%; high p16INK4a, 98%; low pRb, 96%; low CyD1, 93%; and low p53, 84%. Compared to HPV16 tissues as a reference, individual frequencies of these five markers did not differ significantly, either for any of the eight pHR-HPV and the 11 other HR types individually or for the groups of pHR and HR types without HPV16. We conclude that the eight pHR-HPV types, when present as a single infection in CxCa, are biologically active and affect the same cellular pathways as any of the fully recognized carcinogenic HR-HPV types. Therefore we have provided molecular evidence of carcinogenicity for types currently classified as probably/possibly carcinogenic. Although this evidence is crucial for HPV-type carcinogenicity classification, per se it is not sufficient for inclusion of these HPV types into population-wide primary and secondary prevention programmes. Such decisions have to include careful estimation of effectiveness and cost-benefit analyses. Copyright © 2014 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. Source

Discover hidden collaborations