Comprehensive MicroRNA profiling for head and neck squamous cell carcinomas.

Purpose: The objective of this study is to investigate the significance of microRNAs (miRNA) in patients with locally advanced head and neck squamous cell carcinoma (HNSCC).

Experimental Design: A global miRNA profiling was done on 51 formalin-fixed archival HNSCC samples using quantitative reverse transcription-PCR approach, correlated with patients' clinical parameters. Functional characterization of HNSCC-associated miRNAs was conducted on three HNSCC cell lines.

Efficacy of combining GMX1777 with radiation therapy for human head and neck carcinoma.

Purpose: Rapidly metabolizing tumor cells have elevated levels of nicotinamide phosphoribosyltransferase, an enzyme involved in NAD(+) biosynthesis, which serves as an important substrate for proteins involved in DNA repair. GMX1777, which inhibits nicotinamide phosphoribosyltransferase, was evaluated in two human head and neck cancer models in combination with radiotherapy.

Experimental Design: Effects of GMX1777-mediated radiosensitization were examined via metabolic and cytotoxicity assays in vitro; mechanism of action, in vivo antitumor efficacy, and radiosensitization were also investigated.

Oxygen-independent degradation of HIF-alpha via bioengineered VHL tumour suppressor complex.

Tumour hypoxia promotes the accumulation of the otherwise oxygen-labile hypoxia-inducible factor (HIF)-alpha subunit whose expression is associated with cancer progression, poor prognosis and resistance to conventional radiation and chemotherapy. The oxygen-dependent degradation of HIF-alpha is carried out by the von Hippel-Lindau (VHL) protein-containing E3 that directly binds and ubiquitylates HIF-alpha for subsequent proteasomal destruction. Thus, the cellular proteins involved in the VHL-HIF pathway have been recognized as attractive molecular targets for cancer therapy.

Comparative prognostic value of HPV16 E6 mRNA compared with in situ hybridization for human oropharyngeal squamous carcinoma.

Purpose: A significant proportion of oropharyngeal squamous cell carcinomas (OSCC) are associated with the human papilloma virus (HPV), particularly HPV16. The optimal method for HPV determination on archival materials however, remains unclear. We compared a quantitative real-time polymerase chain reaction (qRT-PCR) assay for HPV16 mRNA to a DNA in situ hybridization (ISH) method, and evaluated their significance for overall (OS) and disease-free (DFS) survival.

Characterization of complexation of poly (N-isopropylacrylamide-co-2-(dimethylamino) ethyl methacrylate) thermoresponsive cationic nanogels with salmon sperm DNA.

Thermoresponsive cationic nanogel (TCNG) networks based on N-isopropylacrylamide (NIPAM), 2-(dimethylamino)ethyl methacrylate (DMAEMA), and quaternary alkyl ammonium halide salts of DMAEMA (DMAEMAQ) were synthesized by dispersion polymerization technique. The thermoresponsive properties of TCNGs and TCNG-salmon sperm DNA (sasDNA) polyplexes were characterized in aqueous media of various pH and ionic strength. P[NIPAM] and P[NIPAM/DMAEMA] TCNGs exhibited sharp volume phase transition (VPT) in water at critical temperatures (T(c)) of 32 degrees C and 36 degrees C, respectively.

Significance of Plk1 regulation by miR-100 in human nasopharyngeal cancer.

Polo-like kinase 1 (Plk1) is a critical regulator of many stages of mitosis; increasing evidence indicates that Plk1 overexpression correlates with poor clinical outcome, yet its mechanism of regulation remains unknown. Hence, a detailed evaluation was undertaken of Plk1 expression in human nasopharyngeal cancer (NPC), the cellular effects of targeting Plk1 using siRNA in combination with ionizing radiation (RT) and potential upstream microRNAs (miRs) that might regulate Plk1 expression. Using immunohistochemistry, Plk1 was observed to be overexpressed in 28 of 40 (70%) primary NPC biopsies, which in turn was associated with a higher likelihood of recurrence (p = 0.

Potential use of cetrimonium bromide as an apoptosis-promoting anticancer agent for head and neck cancer.

A potential therapeutic agent for human head and neck cancer (HNC), cetrimonium bromide (CTAB), was identified through a cell-based phenotype-driven high-throughput screen (HTS) of 2000 biologically active or clinically used compounds, followed by in vitro and in vivo characterization of its antitumor efficacy. The preliminary and secondary screens were performed on FaDu (hypopharyngeal squamous cancer) and GM05757 (primary normal fibroblasts), respectively. Potential hit compounds were further evaluated for their anticancer specificity and efficacy in combination with standard therapeutics on a panel of normal and cancer cell lines.

Therapeutic efficacy of seliciclib in combination with ionizing radiation for human nasopharyngeal carcinoma.

Purpose: Seliciclib is a small-molecule cyclin-dependent kinase inhibitor, which has been reported to induce apoptosis and cell cycle arrest in EBV-negative nasopharyngeal carcinoma cell lines. Because most nasopharyngeal carcinoma patients harbor EBV, we proceeded to evaluate the cytotoxic effects of seliciclib in EBV-positive nasopharyngeal carcinoma models.

Experimental Design: Cytotoxicity of seliciclib was investigated in the EBV-positive cell line C666-1 and the C666-1 and C15 xenograft models.

Robust global micro-RNA profiling with formalin-fixed paraffin-embedded breast cancer tissues.

Global micro-RNA (miR) profiling of human malignancies is increasingly performed, but to date, the majority of such analyses have used frozen tissues. However, formalin fixation is the standard and routine histological practice for optimal preservation of cellular morphology. To determine whether miR analysis of formalin-fixed tissues is feasible, quantitative real-time PCR (qRT-PCR) profiling of miR expression in 40 archival formalin-fixed paraffin-embedded (FFPE) breast lumpectomy specimens were performed.

On the path to seeking novel radiosensitizers.

Radiation therapy is a highly effective cancer treatment modality, and extensive investigations have been undertaken over the years to augment its efficacy in the clinic. This review summarizes the current understanding of the biologic bases underpinning many of the clinically used radiosensitizers. In addition, this review illustrates how the advent of innovative, high-throughput technologies with integration of different disciplines could be harnessed for an expeditious discovery process for novel radiosensitizers, providing an exciting future for such pursuits in radiation biology and oncology.

Efficacy of systemically administered mutant vesicular stomatitis virus (VSVDelta51) combined with radiation for nasopharyngeal carcinoma.

Purpose: Nasopharyngeal carcinoma (NPC) is a malignancy of the head and neck region that is associated with EBV latency. Curative treatments for NPC achieve modest survival rates, underscoring a need to develop novel therapies. We evaluated the therapeutic potential of a mutant vesicular stomatitis virus (VSVDelta51) as single treatment modality or in combination with ionizing radiation (RT) in NPC.

Increased efficiency for performing colony formation assays in 96-well plates: novel applications to combination therapies and high-throughput screening.

The colony formation assay (CFA) is the gold standard for measuring the effects of cytotoxic agents on cancer cells in vitro; however, in its traditional 6-well format, it is a time-consuming assay, particularly when evaluating combination therapies. In the interest of increased efficiency, the 6-well CFA was converted to a 96-well format using an automated colony counting algorithm. The 96-well CFA was validated using ionizing radiation therapy on the FaDu (human hypopharyngeal squamous cell) and A549 (human lung) cancer cell lines.

Exendin-4 stimulation of cyclin A2 in beta-cell proliferation.

Objective: Beta-cell proliferation is an important mechanism underlying beta-cell mass adaptation to metabolic demands. We have examined effects, in particular those mediated through intracellular cAMP signaling, of the incretin hormone analog exendin-4 on cell cycle regulation in beta-cells.

Research Design And Methods: Changes in islet protein levels of cyclins and of two critical cell cycle regulators cyclin kinase inhibitor p27 and S-phase kinase-associated protein 2 (Skp2) were assessed in mice treated with exendin-4 and in a mouse model with specific upregulation of nuclear cAMP signaling exhibiting increased beta-cell proliferation (CBP-S436A mouse).

A dose escalation study of hyperfractionated accelerated radiation delivered with integrated neck surgery (HARDWINS) for the management of advanced head and neck cancer.

Background And Purpose: To determine toxicity and outcome of radiation dose escalation with hyperfractionated accelerated radiation delivered with neck surgery (HARDWINS) for head and neck cancer.

Patients And Methods: Patients with stage III and IV squamous cell carcinoma of the oropharynx, hypopharynx or larynx were enrolled. Dose levels of 60, 62 and 64Gy were delivered with twice daily fractionation in 40 fractions over 4 weeks.

Nuclear factor-Y and Epstein Barr virus in nasopharyngeal cancer.

Purpose: The Epstein Barr virus (EBV) is intimately associated with nasopharyngeal cancer (NPC) in a latent state expressing a limited number of genes. The process of switching from latency to replication is not well understood, particularly in response to DNA stress; hence, the focus of this study is on an EBV-positive NPC model.

Experimental Design: C666-1 cells were exposed to radiation (2-15 Gy) or cisplatin (0.

Evaluation of copolymers of N-isopropylacrylamide and 2-dimethyl(aminoethyl)methacrylate in nonviral and adenoviral vectors for gene delivery to nasopharyngeal carcinoma.

Copolymers of 2-dimethyl(aminoethyl) methacrylate (PDMAEM) with N-isopropylacrylamide (NIPAM) were evaluated for their potential to enhance transgene expression of plasmid DNA (pDNA) and gene delivery by adenovirus vectors. The polymers of varying compositions and molecular weights (MW) were synthesized by free-radical polymerization. Polyelectrolyte complexes (PECs) were prepared with different charge (N:P) ratios of PNIPAM/ DMAEM to pDNA.

Dominant-negative HIF-3 alpha 4 suppresses VHL-null renal cell carcinoma progression.

The most prevalent mutations associated with the development of clear-cell renal cell carcinoma (CC-RCC) are the loss-of-function mutations of von Hippel-Lindau (VHL) tumor suppressor gene. These mutations invariably result in an inappropriate accumulation of HIF-alpha due to a failure of VHL as a substrate-recognition component of an E3 ubiquitin ligase complex to target HIFalpha for oxygen-dependent ubiquitin-mediated destruction. Stabilization of HIF-2alpha, but not HIF-1alpha, is the critical oncogenic event upon the functional loss of VHL in the development of CC-RCC.

Local radiotherapy induces homing of hematopoietic stem cells to the irradiated bone marrow.

Local breast radiation therapy (RT) is associated with a 3-fold increased risk of secondary acute myeloid leukemia. As a first step in determining the mechanism(s) underlying this observation, we investigated the role of RT in mediating the active recruitment of hematopoietic stem cells (HSC) to the site of RT. Our results show in a mouse model that local RT delivered to the left leg causes preferential accumulation of bone marrow mononuclear cells to the irradiated site, with maximum signal intensity observed at 7 days post-RT.

Nasopharyngeal cancer: new frontiers from the laboratory to the clinic.

Nasopharyngeal carcinoma (NPC) is a unique malignant epithelial carcinoma of the head-and-neck region, with unique viral biology and geographic distributions in the world. Significant advances have been made in the clinical therapies for NPC, with novel techniques for radiation delivery and randomized trials demonstrating the survival advantage of concurrent chemotherapy for patients with locally advanced diseases. At the same time, there has been an improved understanding of the molecular dysregulations underpinning this disease, with recent discoveries emerging from the use of high-throughput technologies, including microarray expression profiling and robotic screens of chemical libraries.

Five year results of a randomized trial comparing hyperfractionated to conventional radiotherapy over four weeks in locally advanced head and neck cancer.

Background And Purpose: Fractionation strategies delivered over 4 weeks are of clinical and radiobiological interest because treatment is completed before radiotherapy (RT) induced clonogen proliferation commences in earnest approximately 3 to 4 weeks into a course of RT. We wished to test the clinical hypothesis that an increased total dose delivered over 4 weeks with smaller than standard doses per fraction in locally advanced squamous cell carcinoma (SCC) may result in relative protection of late responding tissues and an increased tumor control compared to a conventional daily course in the same overall time.

Materials And Methods: Between 1988 and 1995 a randomized controlled trial employing RT alone was undertaken at the Princess Margaret Hospital that included 331 eligible patients with T3 or T4 N0 or any N-positive oropharynx, hypopharynx, or larynx primary SCC.

Imaging and modulating antisense microdistribution in solid human xenograft tumor models.

Purpose: The tumor microenvironment is complex and heterogeneous, populated by tortuous irregular vasculature, hypoxic cells, and necrotic regions. These factors can all contribute to the biodistribution difficulties encountered by most cancer therapeutic agents. Antisense oligodeoxynucleotides (ASO) are a class of therapeutics where limited information is available about their distribution within a solid tumor environment.

[Bacterial diversity analysis of moderately thermophilic microflora enriched by different energy sources].

Bacterial biodiversities of three moderately thermophilic bioleaching microfloras grown at 50 degrees C on media with pyrite, chalcopyrite, and pure ferrous iron supplemented with sulfur as energy sources were investigated respectively. The 16S rRNA genes of the microorganisms in the cultures flasks were PCR amplified and cloned to identify the bacterial species by comparative sequence analysis, the structural differences of microfloras enriched by different energy sources were compared. A total of 303 clones were recovered and evaluated by restriction fragment length polymorphism (RFLP) analysis.

Imaging the Modulation of Adenoviral Kinetics and Biodistribution for Cancer Gene Therapy.

See page 841 To explore systemic utilization of Epstein-Barr virus (EBV)-specific transcriptionally targeted adenoviruses, three vectors were constructed to examine kinetics, specificity, and biodistribution: adv.oriP.luc, expressing luciferase under EBV-specific control; adv.

Imaging the modulation of adenoviral kinetics and biodistribution for cancer gene therapy.

To explore systemic utilization of Epstein-Barr virus (EBV)-specific transcriptionally targeted adenoviruses, three vectors were constructed to examine kinetics, specificity, and biodistribution: adv.oriP.luc, expressing luciferase under EBV-specific control; adv.