Neuronal Differentiation Capability of Nasal Polyps of Chronic Rhinosinusitis.

Chronic rhinosinusitis with nasal polyps is considered a subgroup of chronic rhinosinusitis and a significant health problem, but the pathogenesis remains unclear to date. Therefore, we investigated the stemness to determine the role of stem cells in nasal polyps, with additional analysis of the neuronal differentiation potential of nasal polyp cells. We determined gene and protein expression profiles of stem cells in nasal polyp tissues, using whole genome microarray, quantitative real-time PCR (qPCR), immunohistochemistry, and flow cytometry. To evaluate the neuronal differentiation potential of nasal polyp cells, we used an efficient xenogeneic co-culture model with unsliced adult rat brain biopsies, followed by qPCR, immunohistochemistry, and growth factor antibody arrays. During gene expression analysis and immunohistochemistry, we were able to detect different stem cell markers, like Oct-4, Sox2, Klf4, c-Myc, ABCG2, Nanog, CD133, and Nestin, which confirmed the existence of stem cell like cells within nasal polyps. In addition, co-culture experiments give evidence for a guided differentiation into the neuronal lineage by overexpression of Nestin, Neurofilament, and GM-CSF. Our study demonstrated the expression of stem cell-related markers in nasal polyps. Furthermore, we characterized, for the first time, the stemness and neuronal differentiation potential of nasal polyp cells. These results gave new insights into the pathogenesis of nasal polyps and its therapeutic effectiveness could represent a promising strategy in the future.

Effects of paclitaxel on permanent head and neck squamous cell carcinoma cell lines and identification of anti-apoptotic caspase 9b.

PURPOSE: Paclitaxel is an effective chemotherapeutic agent against various human tumors inducing apoptosis via binding to ß-tubulin of microtubules and arresting cells mainly in the G2/M phase of the cell cycle. However, the underlying specific molecular mechanisms of paclitaxel on head and neck squamous cell carcinoma (HNSCC) have not been identified yet. METHODS: The apoptotic effects and mechanisms of paclitaxel on different permanent HPV-negative HNSCC cell lines (UT-SCC-24A, UT-SCC-24B, UT-SCC-60A and UT-SCC-60B) were determined by flow cytometry assays, polymerase chain reaction analysis, immunofluorescence-based assays and sequencing studies. RESULTS: Paclitaxel induced a G2/M arrest in HNSCC cell lines followed by an increased amount of apoptotic cells. Moreover, the activation of caspase 8, caspase 10 and caspase 3, and the loss of the mitochondrial outer membrane potential could be observed, whereas an activation of caspase 9 could barely be detected. The efficient activation of caspase 9 was not affected by altered methylation patterns. Our results can show that the promoter region of apoptotic protease activating factor 1 (Apaf-1) was not methylated in the HNSCC cell lines. By sequencing analysis two isoforms of caspase 9, the pro-apoptotic caspase 9 and the anti-apoptotic caspase 9b were identified. The anti-apoptotic caspase 9b is missing the catalytic site and acts as an endogenous inhibitor of apoptosis by blocking the binding of caspase 9 to Apaf-1 to form the apoptosome. CONCLUSION: Our data indicate the presence of anti-apoptotic caspase 9b in HNSCC, which may serve as a promising target to increase chemotherapeutic apoptosis induction.

Stem cell profiling in head and neck cancer reveals an Oct-4 expressing subpopulation with properties of chemoresistance.

OBJECTIVES: In the past decade cancer, including head and neck squamous cell cancer (HNSCC), is increasingly being regarded as a stem cell associated disease which arises from cells with the property of stemness. According to the cancer stem cell (CSC) theory, only a specific subpopulation of cancer cells has the ability to initiate and perpetuate cancer growth, especially under treatment. In this article we describe a subpopulation of cells within HNSCC that expresses the stemness factor Oct-4, which leads to apoptotic resistance after exposure to chemotherapeutic agents. MATERIALS AND METHODS: Permanent cell lines and HNSCC tissue were analyzed for expression of stem cell markers using flow cytometric, immunohistochemical approaches and an antibody based protein array. Chemotherapeutic agent-induced growth inhibition, also known as "enrichment", was determined by the colorimetric cell proliferation assay (MTT-based) and putative stem cell markers were investigated by flow cytometry. RESULTS: Various potential CSC markers were identified in heterogenic expression profiles in permanent cell lines and solid tumors. Our data suggest the Oct-4A isoform as a marker of stemness in HNSCC and the enrichment of cancer stem-like cells by various chemotherapeutic agents was associated with a significantly higher expression of Oct-4. CONCLUSION: This data suggests that many potential CSC markers are expressed on different expression levels in HNSCC. Among these markers Oct-4(A) plays a pivotal role in the detection of cancer cells with enhanced chemoresistance and provide evidence for the existence of cancer stem-like cells in HNSCC.

Cytokine changes in response to radio-/chemotherapeutic treatment in head and neck cancer.

BACKGROUND: Radiation and systemic chemotherapy are standard treatment strategies for advanced or metastatic head and neck cancer. However, little is known about the implications and changes in the tumor microenvironment, including the T-helper (TH)1/TH2 balance in response to these treatment regimens. The aim of the current study was to unravel the effects of chemotherapeutic drugs and radiation on cytokine changes. MATERIALS AND METHODS: In this study, the effect of radiation and chemotherapeutic treatment (5-fluorouracil and cisplatin) on eight cell lines was determined. Before and after exposure, cytokine levels in culture supernatants of cell lines were evaluated using the Bio-Plex Assay (Bio-Rad) and the Human TH1/TH2 Cytometric Bead Array (Becton Dickinson). Results were correlated with parallel measurements for cellular proliferation assessed by cytotoxicity assay. RESULTS: Seven out of eight cell lines of primary tumors or metastases demonstrated an enhanced level of the cytokines interleukin (IL)-1ß, IL-6, IL-8, granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage-colony stimulating factor (GM-CSF) and tumor necrosis factor-α (TNF-α), after sub-lethal radiation doses. Under treatment with low concentrations of 5-fluorouracil and cisplatin, all examined cell lines showed an increasing secretion of the cytokines IL-6 and G-CSF. In contrast, sub-lethal doses of both cytostatic drugs revealed a dose-dependent decrease in secretion IL-1ß. Regarding GM-CSF and TNF-α, we demonstrated an increase in secretion by the primary tumors under low doses of 5-fluorouracil and cisplatin, whereas the metastases showed a sharp drop of GM-CSF and TNF-α secretion. Chemotherapeutic treatment led to no changes of the IL-8 cytokine profile. CONCLUSION: The results suggest complex cytokine changes of the tumor microenvironment and more aberrant expression profiles under treatment with radiation and the chemotherapeutic drugs 5-fluorouracil and cisplatin.