Identification of differentially expressed, tumor-associated proteins in oral squamous cell carcinoma by proteomic analysis

Oral squamous cellular carcinoma is a malignant tumor with poor prognosis and therefore the discovery of early markers to discriminate malignant from normal cells would be of critical importance in clinical diagnosis. Subcellular fractions from oral squamous cell carcinoma (OSCC) and control samples, enriched in mitochondrial and cytosolic proteins, were analyzed by 2-DE, followed by MALDI-TOF-MS. Twenty proteins showed altered expression levels in OSCC; 14 were up- and 6 were down-regulated in comparison with the control samples. For 11 proteins, cofilin, C-reactive protein precursor, creatine kinase m-chain, fatty acid-binding protein, keratin type II, myosin light chain 2 and 3, nucleoside diphosphate kinase A, phosphoglycerate mutase 1, plakoglobulin, and retinoic acid-binding protein II, it is shown for the first time that they are differentially expressed in OSCC. Proteins with highly up-regulated levels may be of interest as potential diagnostic markers and consequently of clinical interest.

Initial effects of low-level laser therapy on growth and differentiation of human osteoblast-like cells

Low-level laser therapy is a clinically well established tool for enhancement of wound healing. In vitro studies have also shown that low level laser therapy has a biostimulatory effect on cells of different origin. The aim of this in vitro study was to investigate the initial effect of low-level laser therapy on growth and differentiation of human osteoblast-like cells. SaOS-2 cells were irradiated with laser doses of 1 J/cm2 and 2 J/cm2 using a diode laser with 670 nm wave length and an output power of 400 mW. Untreated cells were used as controls. At 24 h, 48 h and 72 h post irradiation, cells were collected and assayed for viability of attached cells and alkaline phosphatase specific activity. In addition, mRNA expression levels of osteopontin and collagen type I were assessed using semi-quantitative RT-PCR. Over the observation period, cell viability, alkaline phosphatase activity and the expression of osteopontin and collagen type I mRNA were slightly enhanced in cells irradiated with 1 J/cm2 compared with untreated control cells. Increasing the laser dose to 2 J/cm2 reduced cell viability during the first 48 h and resulted in persistently lower alkaline phosphatase activity compared with the other two groups. The expression of osteopontin and collagen type I mRNA slightly decreased with time in untreated controls and cells irradiated with 1 J/cm2, but their expression was increased by treatment with 2 J/cm2 after 72 h. These results indicate that low-level laser therapy has a biostimulatory effect on human osteoblast-like cells during the first 72 h after irradiation. Further studies are needed to determine the potential of low-level laser therapy as new treatment concept in bone regeneration.

1,25(OH)2 vitamin D3 induces elevated expression of the cell cycle-regulating genes P21 and P27 in squamous carcinoma cell lines of the head and neck

The biologically active form of vitamin D3, 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], inhibits proliferation and induces differentiation for various malignant cells, including squamous cell carcinoma cell lines of the head and neck (SCCHN). These effects are due to an arrest of cells in the G0/G1 phase of the cell cycle and are predominantly mediated by the vitamin D receptor. To further explore the molecular mechanisms of the antiproliferative activity in SCCHN we studied the influence of 1,25(OH)2D3 on the expression of the G1 phase-regulating proteins cyclin D1, p21 and p27. Furthermore, as a direct target of G1 protein complexes, we investigated the phosphorylation status of the retinoblastoma protein (pRb). Synchronized cells of 2 SCCHN cell lines [JPPA (laryngeal carcinoma) and SCC 9 (tongue carcinoma)] and human immortalized keratinocytes (HaCaT) were cultured for 96 h in the presence or absence (ethanol as control) of 1,25(OH)2D3 (10(-7) M). At various time intervals the cell cycle status was detected by fluorescence-activated cell sorting (FACS) analysis and in parallel the expression of cell cycle-regulating proteins was determined at the protein and mRNA levels. In all cell lines tested 1,25(OH)2D3 caused an arrest of cells in the G0/G1 phase of the cell cycle and markedly induced the expression of the inhibitors p21 and p27. No influence was detectable on the expression of cyclin D1. Induction of p21 and p27 mRNA revealed transcriptional regulation by the vitamin D receptor. Simultaneously, hyperphosphorylated pRb was transformed to the hypophosphorylated form. Our results demonstrate that the biologically active form of vitamin D3 directly regulates the expression of p21 and p27, inducing a G0/G1 phase arrest: one mechanism by which 1,25(OH)2D3 controls cell proliferation inSCCHN.

Betulinic acid: a new cytotoxic compound against malignant head and neck cancer cells

BACKGROUND

A new compound, betulinic acid, has been found to be cytotoxic against a variety of tumor cells originating from the neural crest. Its efficacy against head and neck squamous cellular carcinoma cell lines has so far not been tested.

METHODS

Cell numbers were assayed by automated counting; caspase activation and programmed cell death were determined using an antibody specific for an apoptosis-associated epitope in epithelial cells. The expression pattern of Bcl-2 family members was assessed by Western blotting.

RESULTS

In two HNSCC cell lines betulinic acid induced apoptosis, which was characterized by a dose-dependent reduction in cell numbers, emergence of apoptotic cells, and an increase in caspase activity. Western blot analysis of the expression of various Bcl-2 family members in betulinic acid-treated cells showed, surprisingly, a suppression of the expression of the proapoptotic protein Bax but no changes in Mcl-1 or Bcl-2 expression.

CONCLUSION

These data clearly demonstrate for the first time that betulinic acid has apoptotic activity against HNSCC cells.

Cigarette smoke facilitates allergen penetration across respiratory epithelium

BACKGROUND

The association between cigarette smoke exposure and allergic airway disease is a matter for debate. We sought to investigate in an in vitro system whether active smoking reduces the integrity and barrier function of the respiratory epithelium and thus facilitates allergen penetration.

METHODS

We cultured the human bronchial epithelial cell line 16HBE14o- in a transwell culture system as a surrogate for the intact respiratory epithelium. The cell monolayer was exposed to standardized cigarette smoke extract (CSE). The extent and effects of trans-epithelial allergen penetration were measured using 125I-labelled purified major respiratory allergens (rBet v 1, rPhl p 5 and rDer p 2) and histamine release experiments.

RESULTS

Exposure of cells to concentrations of CSE similar to those found in smokers induced the development of para-cellular gaps and a decrease in trans-epithelial resistance. CSE exposure induced a more than threefold increase in allergen penetration. Increased subepithelial allergen concentrations provoked a substantial augmentation of histamine release from sensitized basophils.

CONCLUSIONS

Our results indicate that cigarette smoke is a potent factor capable of reducing the barrier function of the respiratory epithelium for allergens and may contribute to increased allergic inflammation, exacerbation of allergic disease and boosting of IgE memory.

The salivary microbiome as an indicator of carcinogenesis in patients with oropharyngeal squamous cell carcinoma: A pilot study

This study aimed to undertake an initial, comparative analysis of the oral salivary microbiome of patients with oral and oropharyngeal squamous cell carcinoma versus healthy controls. This project, conceived as a pilot study, included 11 patients (1 female, 10 male, mean age 61.6 yrs., SD = 8.2 yrs.) and 11 healthy controls (1 female, 10 male, mean age 46.7 yrs., SD = 15.1 yrs.). Samples of saliva were analysed by high-throughput sequencing of the 16S rRNA gene using the MiSeq platform. Sequence data revealed microbial changes that may mirror disease progression and reflect clinical preconditions such as age, alcohol consumption, tumour size, lymph node status, smoking habit, and tumour HPV-positivity. Consequently, mapping microbial changes in patients with oral and oropharyngeal squamous cell carcinomas might improve our understanding of the pathobiology of the disease, and help in the design of novel diagnostic and treatment strategies.

Neoplastic stem cells: A novel therapeutic target in clinical oncology

Cancer is among the leading causes of morbidity and mortality in the Western world. Despite recent advances, most therapeutic approaches fail to eradicate the entire neoplastic clone. The remaining cells often develop metastasis and/or recurrences and therefore may represent attractive targets of therapy. A new exciting concept in this regard suggests that each neoplasm represents a heterogeneous population of cells that pertain to long-term tumor growth both in vivo in the natural host and in experimental animals. This concept postulates the existence of small fractions of 'tumor stem cells' that exhibit a capacity for self-renewal and unlimited growth and therefore are distinct from their progeny. Based on these hypotheses, the targeting of neoplastic stem cells is considered indispensable for eradication of the entire clone and for the development of curative treatment approaches. However, tumor stem cells often may be quiescent cells and may express a different profile of targets compared with 'more mature' tumor cells. Therefore, current efforts have attempted to characterize target expression profiles in cancer stem cells in various malignancies. In the this review, the authors have provided a brief summary of the current knowledge of neoplastic stem cells and the application of respective concepts in translational oncology with the ultimate objective of improving anticancer therapy.

Invitro study of adherent mandibular osteoblast-like cells on carrier materials

Augmentation of the craniofacial region is necessary for many aesthetic and reconstructive procedures. Tissue engineering offers a new option to supplement existing treatment regimens. In this procedure, materials composed of hydroxyapatite (HA), of synthetic or natural origin, are used as scaffolds. The aim of this study was to evaluate the effects of three HA materials on cultured human osteoblasts in vitro. Explant cultures of cells from human alveolar bone were established. Human osteoblasts were cultured on the surface of HA calcified from red algae (C GRAFT/Algipore), deproteinized bovine HA (Bio-Oss) and bovine HA carrying the cell binding peptide P-15 (Pep Gen P-15). Cultured cells were evaluated with respect to cell attachment, proliferation and differentiation. Cells were cultured for 6 and 21 days under osteogenic differentiation conditions, and tissue-culture polystyrene dishes were used as control. The ability of cells to proliferate and form extracellular matrix on these scaffolds was assessed by a DNA quantification assay, protein synthesis analysis and by scanning electron microscopical examination. Osteogenic differentiation was screened by the expression of alkaline phosphatase. The osteoblastic phenotype of the cells was monitored using mRNA levels of the bone-related proteins including osteocalcin, osteopontin and collagen Type I. We found that cells cultured on C GRAFT/Algipore) and Pep Gen P-15 showed a continuous increase in DNA content and protein synthesis. Cells cultured on Bio-Oss showed a decrease in DNA content from Day 6 (P < 0.05) to Day 21 (P < 0.0001) and protein synthesis on Day 21 (P < 0.005). Alkaline phosphatase activity increased in cells grown on C GRAFT/Algipore and Pep Gen P-15 in contrast to cells grown on Bio-Oss, in which the lowest levels of activity could be observed on Day 21 (P < 0.05). Reverse transcriptase polymerase chain reaction analysis confirmed the osteoblastic phenotype of the cells grown on all three materials throughout the whole culture period. The results of our in vitro study show that the differences in metabolic activity of cells grown on HA materials are directly related to the substrate on which they are grown. They confirm the excellent properties of HA carrying the cell binding peptide P-15 and HA calcified from red algae as used in maxillofacial surgery procedures.

Challenging a dogma – Surgery yields superior long-term results for T1a squamous cell carcinoma of the glottic larynx compared to radiotherapy

AIMS

The aim of this study was to compare laser surgery, conventional endoscopic surgery and radiotherapy in the treatment of early T1a glottic cancer.

METHODS

We conducted a retrospective analysis of patients with early vocal cord cancer (who underwent either conventional surgery via endoscopy or laryngofissur, or primary radiotherapy) at the Medical University of Vienna. By univariate and multivariate Cox regression models the influence of treatment and other parameters on survival and locoregional control were analysed.

RESULTS

337 Patients were analyzed with a mean follow-up period of 133.8 months. Overall survival rates where similar in all three treatment groups. Five-year, 10-year and 15-year estimates of disease specific survival for laser-treated patients were 100%, for conventional surgery were 100%, 98% and 98%, and for radiotherapy were 96%, 92% and 91%, respectively. Locoregional recurrences were observed after laser surgery in 10%, after conventional surgery in 13% and after radiotherapy in 30% of the patients treated. According to the log-rank test, time to relapse was significantly shorter for irradiated patients compared to patients who underwent surgery (p < 0.0001). Mortality caused by the laryngeal tumour was significantly higher in the radiotherapy group (p = 0.003).

CONCLUSION

Patients undergoing laser or conventional surgery have a significantly lower incidence of locoregional recurrences and longer disease-free intervals when compared to patients treated by radiotherapy.

Induction chemotherapy (IC) followed by radiotherapy (RT) versus cetuximab plus IC and RT in advanced laryngeal/hypopharyngeal cancer resectable only by total laryngectomy-final results of the larynx organ preservation trial DeLOS-II

Background

The German multicenter randomized phase II larynx organ preservation (LOP) trial DeLOS-II was carried out to prove the hypothesis that cetuximab (E) added to induction chemotherapy (IC) and radiotherapy improves laryngectomy-free survival (LFS; survival with preserved larynx) in locally advanced laryngeal/hypopharyngeal cancer (LHSCC).

Patients and methods

Treatment-naïve patients with stage III/IV LHSCC amenable to total laryngectomy (TL) were randomized to three cycles IC with TPF [docetaxel (T) and cisplatin (P) 75 mg/m2/day 1, 5-FU (F) 750 mg/m2/day days 1-5] followed by radiotherapy (69.6 Gy) without (A) or with (B) standard dose cetuximab for 16 weeks throughout IC and radiotherapy (TPFE). Response to first IC-cycle (IC-1) with ≥30% endoscopically estimated tumor surface shrinkage (ETSS) was used to define early responders; early salvage TL was recommended to non-responders. The primary objective was 24 months LFS above 35% in arm B.

Results

Of 180 patients randomized (July 2007 to September 2012), 173 fulfilled eligibility criteria (A/B: larynx 44/42, hypopharynx 41/46). Because of 4 therapy-related deaths among the first 64 randomized patients, 5-FU was omitted from IC in the subsequent 112 patients reducing further fatal toxicities. Thus, IC was TPF in 61 patients and TP in 112 patients, respectively. The primary objective (24 months LFS above 35%) was equally met by arms A (40/85, 47.1%) as well as B (41/88, 46.6%). One hundred and twenty-three early responders completed IC+RT; their overall response rates (TPF/TP) were 94.7%/87.2% in A versus 80%/86.0% in B. The 24 months overall survival (OS) rates were 68.2% and 69.3%.

Conclusions

Despite being accompanied by an elevated frequency in adverse events, the IC with TPF/TP plus cetuximab was feasible but showed no superiority to IC with TPF/TP regarding LFS and OS at 24 months. Both early response and 24 months LFS compare very well to previous LOP trials and recommend effective treatment selection and stratification by ETSS.

Clinical trial information

NCT00508664.

In Vitro Growth and Differentiation of Osteoblast-Like Cells on Hydroxyapatite Ceramic Granule Calcified From Red Algae

PURPOSE

The purpose of this study was to analyze the interaction between osteoblast-like cells isolated from mandibular bone and hydroxyapatite ceramic bone substitute obtained from calcified red algae to assess the growth and differentiation of adherent cells on this biomaterial.

MATERIALS AND METHODS

The macroporous ceramic material C GRAFT/Algipore (The Clinician's Preference LLC, Golden, CO) is composed of 100% hydroxyapatite and possesses specific mechanical and physiochemical properties. Osteoblast-like cells were seeded on 200 mg of biomaterial and cultured for 6 and 21 days under osteogenic differentiation conditions. Specific alkaline phosphatase activity, DNA, and protein content of the proliferating cells were analyzed. The morphology of the cells in contact with the biomaterial was examined by scanning electron microscopy. The osteoblastic phenotype of the cells was confirmed by analysis of the expression of bone-specific genes (osteocalcin, osteopontin and collagen type I) by semi-quantitative reverse transcriptase polymerase chain reaction.

RESULTS

The DNA and protein content increased over the culture period. Scanning electron microscopy showed cells spreading on the surface of the biomaterials, covering the macropores, and colonizing the depth of the particles. The analysis of the expression patterns of bone-related genes confirmed the osteoblastic phenotype of the cultured cells.

CONCLUSION

The results of this study showed that hydroxyapatite ceramic bone substitute obtained from calcified red algae support the proliferation and differentiation of human osteoblast-like cells on its surface in vitro and might be suitable for use as scaffolds in tissue engineering strategies in vivo.

Evaluation of spheroid head and neck squamous cell carcinoma cell models in comparison to monolayer cultures

Two-dimensional (2D) monolayer cell culture models are the most common method used to investigate tumor cells in vitro. In the few last decades, a multicellular spheroid model has gained attention due to its adjacency to tumors in vivo. The aim of the present study was to investigate immunohistochemical differences between these two cell culture systems. The FaDu, CAL27 and SCC25 head and neck squamous cell carcinoma (HNSCC) cell lines were seeded out in monolayer and multicellular spheroids. The FaDu and SCC25 cells were treated with increasing doses of cisplatin and irradiation. CAL27 cells were not used in theproliferation experiments, since the spheroids of CAL27 cells were not able to process the reagent in CCK-8 assays. Furthermore, they were stained to present alterations of the following antigens: Ki-67, vascular endothelial growth factor receptor, epithelial growth factor and survivin. Differences in growth rates and expression patterns were detected in certain HNSCC cell lines. The proliferation rates showed a significant divergence of cells grown in the three-dimensional model compared with cells grown in the 2D model. Overall, multicellular spheroids are a promising method to reproduce the immunohistochemical aspects and characteristics of tumor cells, and may show different response rates to therapeutic options.

Primary radiotherapy or postoperative radiotherapy in patients with head and neck cancer: Comparative analysis of inflammation-based prognostic scoring systems

INTRODUCTION

Inflammation-based scoring systems have potential value in evaluating the prognosis of cancer patients; however, detailed comparative analyses in well-characterized head and neck cancer patient collectives are missing.

METHODS

We analyzed overall survival (OS) in locally advanced head and neck cancer patients who were treated with curative intent by primary radiotherapy (RT) alone, by RT in combination with cetuximab (RIT) or with cisplatin (RCHT), and by primary surgery followed by postoperative radiotherapy (PORT). The primary RT collective (N = 170) was analyzed separately from the surgery plus RT group (N = 148). OS was estimated using the Kaplan-Meyer method. Cox proportional-hazard regression models were applied to compare the risk of death among patients stratified according to risk factors and the inflammation-based Glasgow Prognostic Score (GPS), the modified GPS (mGPS), the neutrophil-lymphocyte ratio (NLR), the platelet-lymphocyte ratio (PLR), and the prognostic index (PI).

RESULTS

A prognostic relevance of the scoring systems for OS was observed in the primarily irradiated, but not in the PORT collective. OS was 35.5, 18.8, and 15.4 months, respectively, according to GPS 0, 1, and 2. OS according to mGPS 0-2 was identical. The PLR scoring system was not of prognostic relevance, while OS was 27.3 months in the NLR 0 group and 17.3 months in the NLR 1 group. OS was 35.5 months in PI 0, 16.1 months in PI 1, and 22.6 months in PI 2.

CONCLUSION

GPS/mGPS scoring systems are able to discriminate between three risk groups in primarily, but not postoperatively irradiated locally advanced head and neck cancer patients.

Improved survival in HPV/p16-positive oropharyngeal cancer patients treated with postoperative radiotherapy

INTRODUCTION

In the literature, HPV infection and/or p16 positivity have been consistently demonstrated to correlate with improved response rates in oropharyngeal squamous cell carcinoma (OPSCC) patients treated with primary radiotherapy (RT) alone and in combination with chemotherapy. However, the exact role of HPV/p16 positivity in patients treated with postoperative RT is still unclear.

METHODS

We analyzed tumor samples for HPV-DNA and p16 expression and correlated these variables with treatment outcome in a series of 63 consecutively treated oropharyngeal cancer patients (95% stage III/IV). HPV and p16 analysis were performed using validated test systems. Survival was estimated by the Kaplan-Meier method. Cox proportional hazard regression models were applied to compare the risk of death among patients stratified according to risk factors.

RESULTS

Expression of p16 or high-risk HPV-DNA was detected in 60.3% and 39.6% of the tumors, respectively. p16 expression [overall survival (OS) at 2 years: 91%] as well as HPV infection (OS at 2 years: 95%) was associated with improved OS. Mean survival in p16-positive patients was 112 months compared to 64.6 months in case of p16 negativity. All HPV-positive tumors stained positive for p16. In a multivariable analysis, p16 positivity was associated with improved OS and with disease-free survival.

CONCLUSION

p16 expression and HPV infection are strongly associated with the outcome of postoperatively irradiated OPSCC patients. HPV and p16 double-negative OPSCC patients should be regarded as a distinct "very high-risk patient group" that may benefit from intensified or novel treatment combinations.

Mcl-1, vascular endothelial growth factor-R2, and 14-3-3sigma expression might predict primary response against radiotherapy and chemotherapy in patients with locally advanced squamous cell carcinomas of the head and neck

PURPOSE

This study was done to explore whether the expression of a selected set of proteins could predict primary response to radiotherapy or concomitant radiotherapy and chemotherapy in patients with advanced head and neck cancer.

EXPERIMENTAL DESIGN

Forty-three pretreatment tumor biopsies were taken during diagnostic panendoscopy and examined for Mcl-1, vascular endothelial growth factor (VEGF)-R2, CD9, and 14-3-3sigma expression by immunohistochemistry. Forty-three patients underwent primary radiotherapy, of which, 29 patients received concomitant chemotherapy (low dose daily cisplatin, mitomycin C bolus). The primary end-point was locoregional tumor control 6 months after completion of radiotherapy. Mcl-1, VEGF-R2, CD9, and 14-3-3sigma expression were correlated with patients' primary response to radiotherapy and chemotherapy and with established clinicopathologic variables.

RESULTS

Thirty complete and 13 partial responses were observed in our patient group. High expression levels of Mcl-1 (P=0.021), VEGF-R2 (P=0.032), and 14-3-3sigma (P=0.013), but not of CD9, in tumor biopsies was correlated with complete response. Overexpression of at least two of the three aforementioned proteins in pretreatment biopsies predicted-with a likelihood of 80%-whether a patient would achieve complete response to radiotherapy and chemotherapy. However, if only one of these proteins is overexpressed, there is a likelihood of 84.6% that this patient would not completely respond to therapy.

CONCLUSION

Determining the expression levels of Mcl-1, VEGF-R2, and 14-3-3sigma may be helpful in predicting the early clinical response in head and neck tumor patients receiving primary radiotherapy and chemotherapy and may further allow a pretherapeutic selection of patients.

Analysis of Cell-Seeded 3-Dimensional Bone Constructs Manufactured In Vitro With Hydroxyapatite Granules Obtained From Red Algae

PURPOSE

Bone tissue engineering is a promising approach for the treatment of defective or lost bone in the maxillofacial region. Biocompatible and biodegradable scaffolds seeded with living cells are used to create functional tissue for load-bearing bone reconstruction. The aim of this study was to manufacture cell-seeded 3-dimensional bone constructs based on hydroxyapatite ceramic granule calcified from red algae and mesenchymal cambial-layer precursor cells. The ability of these cells to grow on hydroxyapatite ceramic was quantitatively investigated to evaluate 3-dimensional bone constructs for their potential use in bone tissue engineering.

MATERIALS AND METHODS

Mesenchymal cambial-layer precursor cells were isolated from mandibular periosteum biopsy samples of 3 patients. To manufacture 72 bone constructs, these cells and hydroxyapatite ceramic granules (C GRAFT/Algipore; Clinician's Preference LLC, Golden, CO) were cultivated under osteogenic differentiation conditions in a rotating wall vessel system. After 6 and 21 days, histologic examination and scanning electron microscopy were performed. The absolute DNA content, protein synthesis, and alkaline phosphatase activity were also quantified. The osteoblastic phenotype of the constructs was confirmed by the expression of bone-specific genes (osteocalcin, osteonectin, osteopontin, and core binding factor alpha1) using semiquantitative reverse transcription-polymerase chain reaction and Western blot analysis.

RESULTS

Cells within the constructs showed good viability, which was evidenced by an increase in DNA content over the culture period. The decrease in alkaline phosphatase-specific activity could be an indicator of the maturation of cells and the induction of mineralization. The osteoblastic phenotype of the constructs was demonstrated on protein and at the RNA level over the entire culture period.

CONCLUSION

We observed a positive effect of hydroxyapatite ceramic granules on mesenchymal cambial-layer precursor cell behavior in cell-seeded 3-dimensional bone constructs, indicating the potential applicability of C GRAFT/Algipore composites in bone tissue engineering.

Three-dimensional composites manufactured with human mesenchymal cambial layer precursor cells as an alternative for sinus floor augmentation: an in vitro study

Bone tissue engineering is a promising approach for treatment of defective and lost bone in the maxillofacial region. Creating functional tissue for load bearing bone reconstruction using biocompatible and biodegradable scaffolds seeded with living cells is of crucial importance. The aim of our study was to compare the effects of poly-lactic-co-glycolic acid (PLGA) and hydroxyapatite (HA) ceramic granulae on growth, differentiation, mineralization and gene expression of mandibular mesenchymal cambial layer precursor cells (MCLPCs) cultured onto tissue engineered three-dimensional (3-D) composites in vitro. These 3-D composites were cultivated in a rotating cultivation system under osteogenic differentiation conditions for a maximum period of 21 days. After 6 and 21 days, histological examination was performed; scanning electron microscopy (SEM), alkaline phosphatase (ALP) activity and levels of DNA were investigated. Expression of bone-specific genes osteocalcin, osteonectin, osteopontin, ALP, core binding factor alpha 1 and collagen type I were investigated by using a reverse transcription-polymerase chain reaction (RT-PCR) method. After 6 and 21 days of incubation an initiation of mineralization and the presence of newly formed bone at the surface of the composites were shown after evaluation of ALP activity, DNA content, SEM and histological staining. Expression of bone-specific genes confirmed the bone-like character of these composites and different effects of PLGA or HA granulae on the osteogenic differentiation of human MCLPCs in vitro. The results of this study support the concept that substrate signals significantly influence MCLPCs growth, differentiation, mineralization and gene expression in vitro, and that the use of these cells in the manufacturing of 3-D cell/HA composites is a promising approach for load bearing bone reconstruction in the maxillofacial region in vivo.

Strong evidence for up-regulation of cyclooxygenase-1 in head and neck cancer

BACKGROUND

Cyclooxygenase-1, in contrast to cyclooxygenase-2, is generally reported to be constitutively expressed as a housekeeping enzyme in many different tissues. A number of recently published reports, however, challenge the notion that cyclooxygenase-1 expression is invariably constitutive by demonstrating that this enzyme might be up-regulated under certain pathological conditions in, for example, breast or ovarian cancer cells. In this study we investigated the expression of cyclooxygenase-1 in head and neck tumours and compared it to the cyclooxygenase-1 expression levels in normal oropharyngeal epithelial cells.

MATERIAL AND METHODS

Paraffin-embedded pretreatment biopsies were obtained from head and neck tumour patients (n = 35). In addition, samples of normal oropharyngeal mucosa were taken from patients (n = 12) undergoing routine tonsillectomy. Cyclooxygenase-1 expression levels were determined by immunohistochemistry, Western blotting and real-time RT-PCR in cancerous tissue versus normal mucosa.

RESULTS

Immunohistochemistry revealed overexpression of cyclooxygenase-1 in tumour biopsies compared to normal mucosa. Cyclooxygenase-1 was highly synthesized in the cytoplasm of neoplastic cells while significantly lower levels were detectable in normal mucosal cells. Western blotting and real-time RT-PCR also demonstrated higher cyclooxygenase-1 levels in tumour specimens compared to normal tissue samples.

CONCLUSION

In this study we show for the first time that cyclooxygenase-1 is overexpressed in head and neck cancer cells compared to epithelial cells of normal mucosa.

Arsenic trioxide enhances the cytotoxic effect of cisplatin in head and neck squamous cell carcinoma cell lines

Arsenic trioxide (ATO) has been approved for the treatment of relapsed acute promyelocytic leukaemia. The aim of this study was to determine whether ATO would lead to cell death in head and neck squamous cell carcinoma (HNSCC) cell lines and whether it was able to enhance the cytotoxicity of cisplatin, a standard chemotherapeutic agent. The four HNSCC cell lines SCC9, SCC25, CAL27 and FADU were treated with ATO or cisplatin alone or with ATO and cisplatin in combination. Cytotoxicity assays, immunohistochemistry, western blot analysis and flow cytometry were carried out. Possible interactions between the two drugs were calculated using the Chou-Talalay equation. Ther results demonstrated a synergistic cytotoxic effect of the combination of ATO and cisplatin at high doses. The two agents induced apoptosis in all four HNSCC cell lines. In conclusion, this study showed that ATO is a promising therapeutic drug with cytotoxic effects in HNSCC. We demonstrated a synergistic effect in the combined treatment with cisplatin at high doses.

Expression of hedgehog signaling molecules in Merkel cell carcinoma

BACKGROUND

The Hedgehog signaling pathway is important for human development and carcinogenesis in various malignancies.

METHODS

One tissue microarray with triplets of 28 samples from 25 patients with Merkel cell carcinoma (MCC) was constructed. Six samples of normal skin and 5 samples of normal oral mucosa served as controls. All samples were analyzed immunohistochemically with antibodies directed against Sonic hedgehog, Indian hedgehog, Patched, Smoothened, Gli-1, Gli-2, and Gli-3.

RESULTS

All investigated proteins were frequently and intensely overexpressed in MCCs (Sonic hedgehog, 93%; Indian hedgehog, 84%; Patched, 86%; Smoothened, 79%; Gli-1, 79%; Gli-2, 79%; Gli-3, 86%) compared with control samples. High levels of Patched and Indian hedgehog were significantly associated with an increase in patients overall (p = .015) and recurrence-free survival (p = .011), respectively.

CONCLUSIONS

Our results indicate that the Hedgehog signaling pathway is strongly activated in MCC and thus may play a role in carcinogenesis.

Elevated levels of circulating endothelial progenitor cells in head and neck cancer patients

BACKGROUND AND OBJECTIVES

Measurement of circulating endothelial cells (CECs) and progenitor cells (EPCs) has potential as a surrogate marker for monitoring anticancer treatment. This study evaluated the significance of CECs and EPCs in the blood of patients with head and neck squamous cell carcinoma.

METHODS

In a prospective trial fresh blood samples from 22 tumor patients and 18 controls were tested using multiparametric flow-cytometry. CECs were defined as CD31(+)/CD146(+) and CD45(-)/7AAD(-). EPCs were defined as CD133(+)/KDR(+) and CD3(-)/CD19(-)/CD33(-)/7AAD(-).

RESULTS

Median levels (min/max) of CECs in the tumor group were 2 (0/5) at the time of diagnosis, 1 (0/5) 1 year after therapy and 2 (0/6) in the control cohort. Median levels of EPCs were 5 (1/41) before and 10 (0/21) after treatment in the tumor group compared to 2 (0/7) in the control cohort (P < 0.001 and P = 0.03). CEC and EPC levels showed no apparent correlation with tumor size and response to radiotherapy after 18 months of observation.

CONCLUSIONS

In this pilot study CD133(+)/KDR(+) EPCs were significantly elevated in head and neck tumor patients before and after therapy. Our results warrant further studies on the use of EPCs as a surrogate marker for anticancer therapies in these patients.

Effect of thymoquinone on head and neck squamous cell carcinoma cells in vitro: Synergism with radiation

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.