Ayako Nakanome

An analysis of clinical risk factors of deep neck infection.

OBJECTIVES To clarify the clinical risk factors that aggravate deep neck infection. PATIENTS AND METHODS Sixty-five patients with deep neck infection (abscess or cellulitis), 42 males and 23 females, who were treated at the ear, nose, and throat department in Iwaki Kyoritsu General Hospital in the past 10 years, were retrospectively reviewed. Cases of inflammation of the upper airway including the oral cavity, laryngopharynx, palate tonsil and salivary gland, and cases of lymphadenitis were investigated. These patients were divided into five localized types and one wide range type according to the abscess locations as follows: oral cavity floor type, upper deep cervical type, submandibular type, submental type, retropharyngeal type, and wide range type. RESULTS Seventeen of the 65 patients had diabetes, and significantly more diabetics had the wide range type than the localized type (P<0.05, Fishers test). Diabetes complication was more often seen in the upper deep cervical type among patients aged 61 years or older, and in the wide range type among males aged 41 years or older and elderly women aged 61 years or older. No patients with odontogenic infection or sialolithiasis had associated diabetes mellitus. Two cases developed mediastinitis, and one was caused by retrotonsillar abscess and needed thoracic drainage. More than half of the wide range type cases and more than a quarter of each of the localized type cases except the upper deep cervical type also had laryngeal edema, and eight of them needed emergency tracheotomy. Thirteen of the 40 cases had bacteria belonging to the Streptococcus milleri group (SMG), and all were detected in patients who underwent surgical drainage. Four of the 13 cases where SMG was detected showed drug resistance to some sorts of antibiotics. CONCLUSION Oral disorders can develop deep neck infection independently of the presence of diabetes mellitus, compared with other causes. The presence of diabetes mellitus is associated with deep neck infection, aggravating parotitis and wide spread of inflammation. Retrotonsillar abscess often spreads to the retropharyngeal and parapharyngeal spaces, causing mediastinitis, so caution is necessary. Infection due to SMG tends to form abscess independently of diabetes mellitus. Since more than half of the wide range type and more than a quarter of each of the localized types except the upper deep cervical type were associated with laryngeal edema, airway management should be considered.

Bach1-dependent and -independent Regulation of Heme Oxygenase-1 in Keratinocytes

Bach1 is a member of the basic leucine zipper transcription factor family, and the Bach1/small Maf heterodimer specifically represses transcriptional activity directed by the Maf recognition element (MARE). Because Bach1 is a repressor of the oxidative stress response, we examined the function(s) of Bach1 in keratinocytes subjected to oxidative stress. Oxidative stress induced by H2O2 led to an increase in MARE activity and expression of heme oxygenase-1 (HO-1), an inducible antioxidant defense enzyme. Bach1 depletion by small interfering RNAs or by deletion of Bach1 enhanced HO-1 expression in the absence of H2O2, indicating that Bach1 is a critical repressor of HO-1 in keratinocytes. Although Bach1-deficient or -reduced keratinocytes expressed higher levels of HO-1 than control cells in response to H2O2, Bach1 down-regulation did not attenuate the production of reactive oxygen species by H2O2. In contrast, Bach1 overexpression abolished HO-1 induction by H2O2, which led to increased reactive oxygen species accumulation. HO-1 was induced during keratinocyte differentiation, but MARE activity did not change during differentiation. Furthermore, Bach1 overexpression did not inhibit differentiation-associated induction of HO-1 expression, suggesting that HO-1 induction in differentiation is independent of Bach1. Thus, in response to oxidative stress, Bach1 regulates the oxidation state through the negative control of HO-1 expression prior to terminal keratinocyte differentiation. However, Bach1-mediated repression is negated during keratinocyte differentiation.

Identification of senescence-associated genes and their networks under oxidative stress by the analysis of Bach1.

Cellular senescence is induced in response to DNA damage, caused by genotoxic stresses, including oxidative stress, and serves as a barrier against malignant transformation. Tumor-suppressor protein p53 induces genes critical for implementing cellular senescence. However, the identities of p53 target genes and other regulators that achieve senescence under oxidative stress remain to be elucidated. Effector genes for oxidative stress-induced cellular senescence were sought, based on the fact that transcription factor Bach1 inhibits this response by impeding the transcriptional activity of p53. pRb became hypophosphorylated more rapidly in Bach1-deficient MEFs than in wild-type cells, suggesting that pRb activation was involved in their senescence. Bach1-deficient MEFs bypassed the senescence state when the expression of a subset of p53 target genes, including p21, Pai1, Noxa, and Perp, was simultaneously reduced by using RNAi. Combined knockdown of p21 and pRb resulted in vigorous re-proliferation. These results suggest that oxidative stress-induced cellular senescence is registered by multiple p53 target genes, which arrest proliferation redundantly, in part by activating pRb. Our elucidations contrast with previous reports describing monopolistic regulations of senescence by single p53 target genes.

Simple laryngeal suspension procedure by suturing the digastric muscle to the periosteum of the mandible in neck dissection for tongue cancer

PURPOSE In this article, a simple, new laryngeal suspension procedure is described. The effect of hyoid bone suspension by suturing the digastric muscle to the periosteum of the mandible is analyzed. MATERIALS AND METHODS To elucidate the effect of hyoid bone suspension, CT scans of 26 patients who underwent ipsilateral neck dissection with primary resection of tongue cancer were retrospectively reviewed, and the distance between the hyoid bone and the mandible was measured on the operated and unoperated sides of the neck. A total of 14 patients who underwent suturing of the digastric muscle to the mandible (digastric muscle-sutured group) and the 12 patients who did not (control group) were compared. RESULTS In the digastric muscle-sutured group, the average distance between the hyoid bone and the mandible was significantly smaller on the operated side (17.8 ± 0.57 mm) than on the unoperated side (19.8 ± 0.93 mm; p < 0.05). In the control group, there was no significant difference between the operated side (21.0 ± 1.42 mm) and the unoperated side (19.7 ± 1.39 mm). The difference in the distance between the operated and unoperated sides was significantly larger in the digastric muscle-sutured group (1.97 ± 0.79 mm) than in the control group (-1.32 ± 0.61; p < 0.05). CONCLUSIONS It was shown for the first time that suturing of the digastric muscle to the periosteum of the mandible in neck dissection with primary resection of tongue cancer resulted in hyoid bone suspension. This simple procedure can be useful for laryngeal suspension.

Management of Early-Stage Tongue Cancer

In general, tongue cancer is usually treated surgically and additional therapy is carried out if patients have advanced cancers. Although surgical treatment is performed at the early stage of tongue cancer, still some problems emerge, such as late cervical lymph node metastasis and elective neck dissection. We previously recommended elective neck dissection for patients with T2 tongue cancers (Tateda et al., 2000). However, the range of tumor sizes that would require elective neck dissection remains to be determined.

Abstract B7: Cross‐talk between Bach1, NF‐кB and IL‐6 in epithelial‐mesenchymal transition

The epithelial‐mesenchymal transition (EMT) is a complex biological program that allows cancer cells to aquire motility and invasiveness. Transcriptional repressor Bach1 ( BTB and CNC homology 1 ) belongs to cap9n9collar basic leucin zipper transcription factors family and represses transcription of stress‐responsive genes such as heme oxygenase‐1 ( Hmox‐1 ) and NAD(P)H:quinone oxidoreductase‐1 ( NQO1 ) by binding to the MARE (Maf recognition element) sequenceses in the regulatory regions of these genes. We have recently reported that Bach1 also recruites histon deacetylase‐1 ( HDAC1 ) to a subset of p53 target genes ( Perp1, p21, Noxa, Puma, PAI‐1 ) and contributes to the inhibition of p53‐dependent cellular senescence (Dohi Y. et al. Nat Struct Mol Biol. 2008;15(12):1246–54). In the present study we addressed whether Bach1 regulated cells motility and invasiveness, contributing to EMT. First, we analyzed the phenotype of Bach1‐deficient (Bach1−/−) mice. We found increased spontaneous motility of immortalized embryonic fibroblasts (MEF) derived from Bach1−/− mice in the wound‐healing assay. To identify differential gene expression which might explain enhanced motility of Bach−/− MEFs, we compared gene expression profiles of Bach1−/− and wild type (WT) MEFs. We found that NF‐кB essential modulator, NEMO ( IKBKG ) was highly expressed in Bach1−/− MEFs. Mouse genome database search revealed three MARE sites located in 10 kb upstream of the first exon of NEMO gene. We confirmed that Bach1 bound to these sites in ChIP and EMSA assays and also repressed transcription of the reporter gene construct containing MARE sequences from the NEMO promoter. DNA binding activity of NF‐кB, measured by EMSA, and expression of NF‐кB‐dependent reporter construct were enhanced in Bach1−/− MEFs. To identify Bach1 target genes downstream of NF‐кB, we compared mRNA expression profiles of the Bach1−/− and WT MEFs, treated with TNF‐α. Genes encoding cytokines, chemokines and matrix metalloproteinases ( IL‐6, CXCL‐1, CXCL‐2, MMP2, MMP3, MT2‐MMP ) were up‐regulated in Bach1−/− cells. Interestingly, IL‐6 mRNA level changed earlier and more intensively than other factors; moreover, we detected higher level of IL‐6 in the culture supernatants from Bach1−/− MEFs. Phoshorylation of STAT3, a target of IL‐6 and a regulator of many MMPs and chemokines, was enhanced in Bach1−/− MEFs. RNAi targeting of both NEMO and IL‐6 significantly redused motility of Bach1−/− MEFs indicating causative role of the both factors. Thus, Bach1 may regulate cells motility by fine‐tuning the expression of chemokines and matrix metaloproteinases via cross‐talk with the NF‐кB signal transduction pathway in IL‐6 dependent manner. Next, we addressed whether the lost of Bach1 in epithelia or stroma would activate EMT program in cancer cells. RNAi targeting of Bach1 in breast cancer cell line MCF‐7 resulted in lower E‐cadherin expression, reduced number of cell‐to‐cell, cell‐to‐substrate contacts and increased spontaneous motility. Co‐culture with Bach1−/− but not WT MEFs induced transwell migration and basement membrane matrix invasion of MCF‐7 cells. In conclusion, our data indicate that Bach1 regulates cell autonomous and non‐autonomous induction of chemokines and extracellular matrix degrading enzymes, inhibiting motility, invasiveness and EMT. Citation Information: Cancer Res 2009;69(23 Suppl):B7.