Atsuro Sugita

Telomerase components as a diagnostic tool in human oral lesions

Telomerase activity is considered to be a diagnostic marker of malignancy since most malignant cells express this activity and most somatic cells do not. However, the detection of telomerase activity is rather complicated and is affected by many factors. Recently, human telomerase components were cloned and found to consist of 3 subunits. We assessed which component of telomerase best correlates with malignancy in order to study the possibilities for developing a new diagnostic marker. Telomerase activity was measured by a telomeric repeat amplification protocol (TRAP) assay, and the telomerase components hTR, hTRT-mRNA and TP1-mRNA were detected by the reverse transcriptase-polymerase chain reaction (RT-PCR). Twenty-five of 26 oral malignant lesions, 9 of 22 benign lesions and none of 19 normal control tissues exhibited distinct telomerase activity. hTR and TP1-mRNA expression levels were detected in all malignant lesions and normal control tissues and had no significant correlation with the telomerase activity results. In contrast, hTRT-mRNA expression was closely associated with telomerase activity. All lesions expressing hTRT were telomerase positive. In addition, some samples of dysplastic lesions, benign tumors, lichen planus and normal mucosa exhibiting poor telomerase activity revealed weak expression of hTRT. Expression levels of hTRT-mRNA positively correlated with clinical and pathological findings. Detection of hTRT-mRNA by RT-PCR appeared to be more sensitive for telomerase than measurement of telomerase activity by the TRAP assay. Detection of hTRT-mRNA may provide information useful in the diagnosis of oral malignancies.

Incidence of p53 and Ha‐ras gene mutations in chemically induced rat mammary carcinomas

To determine whether p53 alterations, which are frequent in human breast cancers, are also common in rat mammary tumors, we examined 40 tumors from 24 rats treated with 7,12‐dimethylbenz[a]anthracene (DMBA) and 34 tumors from 14 rats treated with N‐nitroso‐N‐methylurea (NMU) (an N‐nitroso compound). DMBA and NMU are known genotoxic mutagens. The entire coding regions of the p53 and Ha‐ras genes were examined for mutations by polymerase chain reaction single‐strand conformational polymorphism analysis and by direct sequencing. One of the 40 DMBA‐induced mammary tumors had a p53 mutation, a single‐base substitution (???AGC→???GGC) at codon 307, resulting in an amino‐acid change from Ser to Gly. No mutations were found in NMU‐induced tumors. The incidence of Ha‐ras gene mutation was 79% (27 of 34) at codon 12 in the NMU group and 23% (nine of 40) at codon 61 in the DMBA group. Thus, p53 mutation, in contrast to Ha‐ras mutation, did not seem to be a prerequisite for carcinogenesis in chemically induced rat mammary tumors.

Effect of dienogest administration on angiogenesis and hemodynamics in a rat endometrial autograft model

BACKGROUND We aimed to establish an endometrial autograft model in rats that would allow for repetitive in vivo analyses of angiogenesis. Dienogest (DNG) is an orally active progestin used for the treatment of endometriosis. We investigated whether DNG would affect angiogenesis of the ectopic endometrium in our model. METHODS Mechanically isolated endometrial fragments were transplanted into dorsal skinfold chambers in rats. We analyzed the effect of DNG on angiogenesis of the ectopic endometrium on Days 0, 2, 4, 7, 10 and 14 after transplantation using intravital fluorescence microscopy. RESULTS The DNG-administered group showed significant suppression of angiogenesis of endometrial autografts, as indicated by the reduced size of the microvascular network and decreased microvessel density compared with those of control animals. The newly formed microvessels of the DNG-administered group showed consistently elevated diameters and centerline red blood cell velocity was decreased. Immunohistochemistry revealed a significant reduction in the level of perivascular α-smooth muscle actin within endometrial grafts of the DNG-administered group. CONCLUSIONS DNG inhibited angiogenesis of the ectopic endometrium, with confirmed structural changes in the microvessels.

Prognostic significance of interleukin-8 and CD163-positive cell-infiltration in tumor tissues in patients with oral squamous cell carcinoma

Purpose We investigated whether serum interleukin (IL)-8 reflects the tumor microenvironment and has prognostic value in patients with oral squamous cell carcinoma (OSCC). Experimental Design Fifty OSCC patients who received radical resection of their tumor(s) were enrolled. Preoperative sera were measured for IL-8 by ELISA. Expression of IL-8 and the infiltration of immune cells in tumor tissues were analyzed by an immunohistochemical staining of surgical specimens. Results We found that disease-free survival (DFS) was significantly longer in the Stage I/II OSCC patients with low serum IL-8 levels compared to those with high levels (p = 0.001). The tumor expression of IL-8, i.e., IL-8(T) and the density of CD163-positive cells in the tumor invasive front, i.e., CD163(IF) were correlated with the serum IL-8 level (p = 0.033 and p = 0.038, respectively), and they were associated with poor clinical outcome (p = 0.007 and p = 0.002, respectively, in DFS) in all patients. A multivariate analysis revealed that N status, IL-8(T) and CD163(IF) significantly affected the DFS of the patients. Further analysis suggested that combination of N status with serum IL-8, IL-8(T) or CD163(IF) may be a new criterion for discriminating between OSCC patients at high and low risk for tumor relapse. Interestingly, the in vitro experiments demonstrated that IL-8 enhanced generation of CD163-positive M2 macrophages from peripheral blood monocytes, and that the cells produced IL-10. Conclusions These findings indicate that IL-8 may be involved in poor clinical outcomes via generation of CD163-positive M2 macrophages, and that these factors in addition to N status may have prognostic value in patients with resectable OSCSS.

Identification of anti-α-enolase autoantibody as a novel serum marker for endometriosis

Diagnosis of endometriosis needs invasive maneuvers. New serum marker that possesses both high sensitivity and high specificity has long been desired. To establish novel serum marker for endometriosis, serum autoantibodies (autoAbs) were investigated using proteomic approach. AutoAbs in sera of endometriotic patients and healthy controls were analyzed using a mesothelial cell line, 2‐DE and Western blotting. Proteins in reacted spots were identified using MALDI TOF‐MS with MASCOT analysis. ELISAs were established using recombinant proteins and autoAb‐titers were estimated in sera of endometriotic patients, disease and healthy controls. Several autoAbs were identified. Anti‐α‐enolase (Eno1)‐autoAb levels in endometriotic patients were significantly elevated compared with both healthy and disease controls. Sensitivity and specificity of serum anti‐Eno1‐autoAb was nearly comparable to serum CA125. When anti‐Eno1‐autoAb and CA125 assays were combined, diagnostic sensitivity and accuracy improved. Serum anti‐Eno1‐autoAb can be a new serum endometriotic marker and it is useful as a supplement assay for CA125. This study validates further clinical evaluation of this novel marker.

Phosphodiesterase 3B gene expression is enhanced in the liver but reduced in the adipose tissue of obese insulin-resistant db/db mouse

Phosphodiesterase (PDE) 3B, when activated by insulin, causes a decrease in intracellular cAMP concentration. The activation of this enzyme results in the reduced output of free fatty acids (FFA) from adipocytes, and an increased lipogenesis in liver. We have recently shown that PDE3B gene expression is reduced in adipose tissues of KKAy mice. We intend to further elucidate the regulation of PDE3B in liver as well as adipose tissues in relation to the insulin resistant state. We examined PDE3B gene expression in liver and adipose tissues of obese, insulin-resistant diabetic db/db mice and also checked the effect of an insulin-sensitizing drug, troglitazone, on this gene expression. In the liver of db/db mice, PDE3B mRNA, its corresponding protein, and the associated catalytic activity were all increased by 2.1, 1.9 and 1.6-fold, respectively, over those in db/+ control mice. Histological examination revealed substantial triglyceride storage in the liver of db/db mice. Conversely, in the adipose tissue of db/db mice, PDE3B mRNA, protein, and its associated activity were all decreased by 0.38, 0.33 and 0.36-fold, respectively. Troglitazone, which has no effect on PDE3B in liver, increased the expression of this gene in adipocytes. This increase is associated with a reduction in the elevated levels of serum insulin, glucose, FFA and triglycerides. The reduced PDE3B gene expression in adipose tissues, which results in the elevation of serum FFA, could be the primary event in the development of insulin resistance in db/db mice. The enhanced PDE3B gene expression may correlate with changes in triglyceride storage in the liver of these mice.

Mandibular osteoblastic metastasis of poorly differentiated carcinoma of the thyroid gland

Metastasis of malignant tumors to the oral cavity is rare. The authors report a case of thyroid carcinoma with mandibular osteoblastic metastasis. An 83-year-old female presented with lower jaw swelling and pain. An elastic hard subcutaneous mass was observed in the median mandible. X-ray images confirmed a tumor lesion with periosteal reaction spreading radially from the mandible. A biopsy revealed nests of large, polygonal tumor cells growing in a supporting fibrovascular framework. The patients anamnesis included thyroid carcinoma with lung metastasis, 2 years ago, treated by total enucleation of the thyroid and excision of the superior lobe of the left lung. Biopsy, primary and metastatic tumor samples all tested positive for thyroglobulin, suggesting a thyroid follicular epithelial origin. Mandibular metastasis of poorly differentiated carcinoma of the thyroid gland was diagnosed. Consent for further treatment was not obtained. The patient died 1 year and 7 months later.

Telomerase activation and cell proliferation during 7,12-dimethylbenz[a]anthracene–induced hamster cheek pouch carcinogenesis

Telomerase is a ribonucleoprotein complex intimately involved in cell immortalization and carcinogenesis. This enzyme is activated and stabilizes telomere length in almost all types of cancer. Telomerase may be necessary for continuous cell proliferation. In this study, we analyzed telomerase activity in hamster experimental oral lesions (starting from epithelial hyperplasia through dysplasia, carcinoma in situ, and invasive carcinoma) evoked by 7,12‐dimethylbenz[a]anthracene, and in normal mucosa. We also analyzed proliferative activity in these lesions by using immunohistochemical analysis and flow cytometry. Histologically normal epithelium expressed weak telomerase activity. The telomerase activity count increased rapidly in the early stage of carcinogenesis and gradually in the late stage. Cell‐proliferative activity closely correlated with progression of disease. These findings indicate that telomerase activation is an early event and that increases in telomerase activity upregulate cell proliferation in chemically induced hamster oral carcinogenesis. Mol. Carcinog. 25:164–168, 1999.

Visual assessment of Ki67 using a 5-grade scale (Eye-5) is easy and practical to classify breast cancer subtypes with high reproducibility

Aims Personalised breast cancer therapy requires pathological characterisation of tumours. The proliferative index, based on Ki67, is pivotal, but a standard method has not been established. Here we look for an easy and practical way to evaluate Ki67. Methods Immunohistochemical staining of estrogen receptors, progesterone receptors, HER2 and Ki67 (MIB-1) was performed on resected specimens from 406 primary invasive ductal carcinomas. Ki67 labelling index (LI) from manual counting was compared with visual assessment using a 5-grade scale (Eye-5). Next, 10 pathologists evaluated 100 samples with marked hot spots by using Eye-5. Another 100 samples without marking were also assessed by eight pathologists. One year later, two pathologists reviewed 222 cases with Eye-5. Prognosis was analysed among estrogen receptor-positive cases with postoperative endocrine therapy. Results Eye-5 showed good correlation to LI. All 136 cases of score 4–5 had LI >20% and all 56 cases of score 1 had LI<20%, which means that manual counting was not necessary for about half of the cases. Interobserver and intraobserver variability was low even when a hot spot was not fixed. Eye-5 also correlated with histological grade and lymph node metastasis. Combining Eye-5 and histological grade created a new algorism to predict LI, which allows 80% of all cases (74% of luminal cases) without manual counting. Cases of Eye-5 score 1–2 had significantly better survival than score 3–5. Conclusions Visual assessment of Ki67 by a 5-grade scale (Eye-5) is fast, easy, and reliable with acceptably low interobserver and intraobserver variability. Eye-5 can replace LI in many luminal tumours, and is a strong candidate as a standard method of evaluating Ki67.

Role of activation‐induced cytidine deaminase in the progression of follicular lymphoma

Activation‐induced cytidine deaminase (AID/AICDA) is required for somatic hypermutation and class‐switch recombination of the immunoglobulin gene, and for c‐myc translocation of germinal center‐derived B‐cell lymphoma. In the present study, we attempted to clarify the significance of AID associated with c‐myc in the progression of follicular lymphoma (FL) using RT‐PCR and quantitative real‐time PCR. Tissues from the patients with grade 3 FL expressed relatively higher levels of c‐myc and AID. The samples taken from a patient with FL who died within 2 years after the start of treatment showed either no or low expression of AID, despite expressing high levels of c‐myc. In order to examine the role of AID expression in rapidly progressive FL, the full‐length AID transcript was transfected into AID‐negative cell lines established from different patients with rapidly progressive FL. This led to the establishment of AID‐expressing transfectants with a low proliferation rate and a significantly increased incidence of G0/G1 arrest compared with controls. Our results indicate that AID may act as a negative regulator of cell survival in FL when sufficient c‐myc is expressed. Switch‐off or low expression of AID after c‐myc amplification may correlate with the clinical outcomes of FL. (Cancer Sci 2012; 103: 415–421)