Normal Oral Tissues Research Articles

Native Fluorescence and Time Resolved Fluorescence Spectroscopic Characterization of Normal and Malignant Oral Tissues Under UV Excitation—an In Vitro Study

The present work aims to investigates the native fluorescence and time resolved fluorescence spectroscopic characterization of oral tissues under UV excitation. The fluorescence emission spectra of oral tissues at 280nm excitation were obtained. From the spectra, it was observed that the alteration in the biochemical and morphological changes present in tissues. Subsequently, the Full width at Half Maximum (FWHM) of every individual spectra of 20 normal and 40 malignant subjects were calculated. The student's t-test analysis reveals that the data were statistically significant (p = 0.001). The fluorescence excitation spectra at 350nm emission of malignant tissues confirms the alteration in protein fluorescence with respect to normal counterpart. To quantify the observed spectral differences, the two ratio variables R1 = I275/I310 and R2 = I310/I328 were introduced in the excitation spectra. Among them, the Linear Discriminant Analysis (LDA) of R1 reveals better classification with 86.4% specificity and 82.5% sensitivity. The fluorescence decay kinetics of oral tissues was obtained at 350nm emission and it was found that the decay kinetics was triple exponential. Then the ROC analysis of fractional amplitudes and component lifetime reveals that the average lifetime shows 77% sensitivity and 70% specificity with the cut off value 4.85ns. Briefly, the average lifetime exhibits better statistical significance when compared to fractional amplitudes and component lifetimes.

Characterization of three novel human papillomavirus types isolated from oral rinse samples of healthy individuals

BackgroundDespite the strong evidence of HPV infection as the etiological agent in a subset of oral cancer, oral α-HPV detection is rare in healthy individuals, and little is known of the existing of novel HPV types in oral cavity. ObjectiveWe determined whether novel HPV types can be isolated from oral rinse samples collected from healthy individuals. Study designWe performed rolling circle amplification (RCA) coupled with degenerated PCR assay on 48 oral rinse samples to amplify novel HPV types. Full length HPV DNA was cloned using long range PCR. Quantitative type specific Taqman assays were used to determine the prevalence of novel HPV types in 158 archived oral tissue samples. ResultsWe were able to isolate four novel human papillomavirus types. Full length HPV DNA was cloned for three of the four novel HPV types. All four HPV types belong to the genus Gammapapillomavirus (γ-PV), where HPV 171 is most closely related to HPV 169, showing 88% similarity; HPV 172 is most closely related to HPV 156, showing 70% similarity; HPV 173 is most closely related to HPV 4, showing 73% similarity; oral sample lavage (OSL) 37 is most closely related to HPV 144, showing 69% similarity. Finally, we showed that HPV 173 was rarely present in oral tissues (2/158), HPV 172 was only detected in normal oral tissues (25/76), and HPV 171 was more prevalent in malignant oral tissues (17/82 vs. 10/76, p=0.21). ConclusionsNovel γ-HPV types are present in oral cavity of healthy individuals.

Vascular endothelial growth factor (VEGF) and inducible nitric oxide synthase (iNOS) in oral lichen planus: An immunohistochemical study for the correlation between vascular and inflammatory reactions

ObjectivesOral lichen planus (OLP) is characterized by a subepithelial lymphocytic infiltration. To find the correlation between vascular and inflammatory reaction, the expressions of vascular endothelial growth factor (VEGF), inducible nitric oxide synthase (iNOS), CD34, and CD68 were investigated. Materials and methods30 cases of OLP and 20 normal oral tissues samples were subjected to immunohistochemistry for VEGF, iNOS, CD34 and CD68. CD34-positive (+) blood vessels (microvessel density, MVD), degree of lymphocytic infiltration, and CD68+ macrophages were correlated with the expression of VEGF and iNOS. OLP cases were histopathologically subdivided into active (non erosive and erosive/ulcerative) and non-active stages. ResultsExpression of VEGF was observed in all epithelial layers of OLP while iNOS was in basal and parabasal layers. They were significantly higher (P<0.001) than those in controls. The mean MVD (CD34+) was significantly increased in all cases of OLP (P<0.05), especially in the active (erosive/ulcerative) stage (P<0.01) compared with controls. The mean number of CD68+ cells was significantly increased (P<0.01) in OLP, especially higher in the active (erosive/ulcerative) OLP (P<0.001). The expressions of VEGF (P<0.05) and iNOS (P<0.01) were significantly correlated in OLP. There was significant positive correlations between the lymphocytic infiltration and the expressions of VEGF and iNOS (P<0.05), MVD (P<0.01), and CD68 counts (P<0.001) in OLP. ConclusionThe present results indicated that the upregulation of VEGF and iNOS plays an important role in pathogenesis of OLP through activated angiogenesis and chronic inflammatory cell infiltrates. Novel strategies directed to inhibition of these markers could be developed for OLP treatment.

S100A7 overexpression is a predictive marker for high risk of malignant transformation in oral dysplasia

Early detection of oral lesions (OLs) at high risk of cancer development is of utmost importance for intervention. There is an urgent unmet clinical need for biomarkers that allow identification of high-risk OLs. Recently, we identified and verified a panel of five candidate protein biomarkers namely S100A7, prothymosin alpha, 14-3-3ζ, 14-3-3σ and heterogeneous nuclear ribonucleoprotein K using proteomics to distinguish OLs with dysplasia and oral cancers from normal oral tissues. The objective of our study was to evaluate the potential of these candidate protein biomarkers for identification of oral dysplastic lesions at high risk of cancer development. Using immunohistochemistry, we analyzed expressions of these five candidate protein biomarkers in 110 patients with biopsy-proven oral dysplasia and known clinical outcome and determined their correlations with p16 expression and HPV 16/18 status. Kaplan-Meier survival analysis showed reduced oral cancer-free survival (OCFS) of 68.6 months (p = 0.007) in patients showing cytoplasmic S100A7 overexpression when compared to patients with weak or no S100A7 immunostaining in cytoplasm (mean OCFS = 122.8 months). Multivariate Cox regression analysis revealed cytoplasmic S100A7 overexpression as the most significant candidate marker associated with cancer development in dysplastic lesions (p = 0.041, hazard ratio = 2.36). In conclusion, our study suggested the potential of S100A7 overexpression in identifying OLs with dysplasia at high risk of cancer development.

Novel antioxidants are not toxic to normal tissues but effectively kill cancer cells

Free radicals are formed as a result of cellular processes and play a key role in predisposition to and development of numerous diseases and of premature aging. Recently, we reported the syntheses of a number of novel phenolic antioxidants for possible application in food industry. In the present study, analyses of the cellular processes and molecular gene expression effects of some of the novel antioxidants in normal human tissues and in cancer cells were undertaken. Results indicated that whereas the examined antioxidants showed no effects on morphology and gene expression of normal human oral and gingival epithelial tissues, they exerted a profound cell killing effect on breast cancer cells, including on chemotherapy-resistant breast cancer cells and on oral squamous carcinoma cells. Among the tested antioxidants, N-decyl-N-(3-methoxy-4-hydroxybenzyl)-3-(3,4-dihydroxyphenyl) propanamide and N-decyl-N-(3,5-dimethoxy-4-hydroxybenzyl)-3-(3,4-dihydroxyphenyl) propanamide were the most promising, with excellent potential for cancer treatment. Moreover, our gene expression databases can be used as a roadmap for future analysis of mechanisms of antioxidant action.

Apoptosis in normal oral tissues and odontogenesis

AbstractProgrammed cell death or apoptosis is considered a vital component of various processes including normal cell turnover, proper development and functioning of the immune system, hormone-dependent atrophy, embryonic development, and chemical-induced cell death. Inappropriate apoptosis (either too little or too much) is a factor in many human conditions including neurodegenerative diseases, ischemic damage, autoimmune disorders, and many types of cancers. The process of apoptosis is generally characterized by distinct morphological characteristics and energy-dependent biochemical mechanisms. An understanding of its role in the pathophysiology of oral tissues is pertinent to the development of novel therapeutic approaches. The developing tooth passes through the various morphologic stages and apoptosis is observed selectively in certain locations. This review focuses on the current knowledge of apoptosis emphasizing its role in normal oral tissues and odontogenesis.

Clinical Significance of Altered Expression of β-Catenin and E-Cadherin in Oral Dysplasia and Cancer: Potential Link with ALCAM Expression

BackgroundPerturbations in cell adhesion molecules are linked to alterations in cadherin-catenin complexes and likely play major roles in invasion and metastasis; their impact on early precancerous stages remains yet unknown. We showed ALCAM overexpression in early oral lesions and its cytoplasmic accumulation in oral squamous cell carcinoma (OSCC) to be a predictor of disease progression and poor prognosis. This study tested the hypothesis that alterations in E-cadherin and β -catenin expressions are early events in oral tumorigenesis, associated with disease prognosis, and correlate with perturbations in ALCAM expression.MethodsExpressions of E-cadherin and β-catenin were analyzed in the same cohort of 105 OSCCs, 76 oral lesions and 30 normal oral tissues by immunohistochemistry and correlated with clinicopathological parameters and prognosis. The effect of siRNA mediated ALCAM knockdown on E-cadherin and β -catenin was determined using western blot, confocal microscopy and RT-PCR analysis in oral cancer cells.ResultsSignificant loss of membranous E-cadherin and β-catenin expression was observed from normal, hyperplasia, dysplasia to OSCCs (ptrend <0.001); and correlated with cytoplasmic ALCAM accumulation in OSCCs (p = 0.006). Multivariate analysis revealed β-catenin membrane loss and ALCAM/β-cateninnuclear/cytoplasmic accumulation to be significant predictors for late clinical stage (p<0.001, OR = 8.7; p = 0.006, OR = 9.9, respectively) and nodal metastasis (p = 0.003, OR = 3.8; p = 0.025, OR = 3.4 respectively). Cox’s regression showed E-cadherin membrane loss/ALCAM cytoplasmic expression [p<0.001; HR = 4.8] to be independent adverse prognosticators in OSCCs. siRNA mediated silencing of ALCAM resulted in concurrent increase in E-cadherin and β-catenin both at the transcript and protein levels.ConclusionsLosses of E-cadherin and β-catenin expressions are early events in oral tumorigenesis; their associations with aggressive tumor behavior and disease recurrence underscore their potential as prognostic markers. Correlation of loss of E-cadherin and β-catenin with cytoplasmic ALCAM accumulation both in vitro and in in vivo suggests that these dynamic changes in cell adhesion system may play pivotal role in oral cancer.

Repression of G protein–coupled receptor family C group 5 member A is associated with pathologic differentiation grade of oral squamous cell carcinoma

G protein-coupled receptor family C group 5 member A (GPRC5A), a member of G protein-coupled receptor family, has been shown to function as a tumor suppressor in lung tissue. The biological functions of GPRC5A have therefore been linked to lung tissue. However, the biological significance of this gene product remains obscure. In this study, we investigated the expression of GPRC5A proteins in normal oral tissue and oral squamous cell carcinoma (OSCC), and we characterized its biological activity in OSCC cell lines. Western blot analysis and immunohistochemical staining were used to investigate the expression of GPRC5A in both OSCC cell lines and clinical samples. GPRC5A stable transfectants and their parental OSCC cells were characterized for their biological activities in anchorage-independent growth. High levels of immunohistochemical GPRC5A expression were detected in normal oral tissue, especially differentiated area. In contrast, GPRC5A expression was dramatically repressed in OSCCs (P<0.01). The immunohistochemical GPRC5A expression was moderately well differentiated, but greatly repressed in moderately differentiated OSCCs and completely repressed in poorly differentiated OSCCs. Overexpression of GPRC5A in OSCC CAL27 cells resulted in a suppressed anchorage-independent growth activity, a transforming phenotype. GPRC5A is expressed in normal oral epithelium. Repression of GPRC5A is associated with poorly differential grade of OSCCs. Overexpression of GPRC5A in OSCC cell line reversed the malignant phenotype. Thus, GPRC5A is important for homeostasis in oral tissue, and deletion or repression of this gene may involve in tumorigenesis of OSCCs and may serve as a prognostic marker for malignant type of OSCCs.

MicroRNAs as tumour suppressors in canine and human melanoma cells and as a prognostic factor in canine melanomas

Malignant melanoma (MM) is one of the most aggressive cancers in dogs and in humans. However, the molecular mechanisms of its development and progression remain unclear. Presently, we examined the expression profile of microRNAs (miRs) in canine oral MM tissues and paired normal oral mucosa tissues by using the microRNA-microarray assay and quantitative RT-PCR. Importantly, a decreased expression of miR-203 was significantly associated with a shorter survival time. Also, miR-203 and -205 were markedly down-regulated in canine and human MM cell lines tested. Furthermore, the ectopic expression of miR-205 had a significant inhibitory effect on the cell growth of canine and human melanoma cells tested by targeting erbb3. Our data suggest that miR-203 is a new prognostic factor in canine oral MMs and that miR-205 functions as a tumour suppressor by targeting erbb3 in both canine and human MM cells.

OP051: An investigation of the insulin-like growth factor pathway on oral carcinogenesis in patients with diabetes mellitus

Mammalian target of rapamycin (mTOR) is an important regulator of protein translation, biosynthesis, cell growth and cell proliferation, is over-activated in various human malignancies, but very few studies have yet to explore the mTOR activity in oral squamous cell carcinoma (OSCC), which is the 7th leading death of malignancy in Taiwan. We collect tissue samples of 58 OSCC patients from Taipei veteran general hospital during along with their clinical parameters. Immunohistochemical (IHC) staining was performed on the tissues for investigating active mTOR (p-mTOR) expression level with the use of tissue microarray (TMA) technique. The results revealed p-mTOR expression level in OSCC tissues are significantly higher than in normal oral mucosal tissues ( p p = 0.0391) and higher tumor recurrence after adjuvant cisplantin treatment ( p = 0.0159). Although positive group shows a relatively rapid descent on survival curves, no significant difference between positive and negative group in over-all survival rate ( p = 0.1064), cancer specific survival rate ( p = 0.0914) and disease free survival rate ( p = 0.0509). p-mTOR expression level in OSCC correlates to tumor recurrence, possible poorer survival rate and may even associate with cisplantin resistance in our study. A scale-up study in the future may further elucidate the role of mTOR in OSCC.

Mechanisms of oral carcinogenesis induced by dibenzo[a,l]pyrene: An environmental pollutant and a tobacco smoke constituent

We previously reported that dibenzo[a,l]pyrene (DB[a,l]P), the most potent known environmental carcinogen among polycyclic aromatic hydrocarbons (PAH) congeners, is carcinogenic in the oral tissues of mice. We have now developed a new mouse model which employs the oral application of the fjord region diol epoxide, (±)-anti-11,12-dihydroxy-13,14-epoxy-11,12,13,14-tetrahydrodibenzo[a,l]pyrene (DB[a,l]PDE), a metabolite of the tobacco smoke constituent DB[a,l]P, and we show its specific induction of oral squamous cell carcinoma (OSCC) in both tongue and other oral tissues. Groups of B6C3F1 mice (20/group) received 6 or 3 nmol of (±)-anti-DB[a,l]PDE administered into the oral cavity; 3 times per week for 38 weeks. Additional groups received the vehicle alone or were left untreated. Mice were sacrificed 42 weeks after the first carcinogen administration. The high dose induced 74 and 100% OSCC in the tongue and other oral tissues, respectively; the corresponding values at the lower dose were 45 and 89%. Using immunohistochemistry, we showed that DB[a,l]PDE resulted in overexpression of p53 and COX-2 proteins in malignant tissues when compared to normal oral tissues and tongues. Consistent with the carcinogenicity, we demonstrated powerful mutagenicity in cII gene in B6C3F1 (Big Blue) mouse tongue. The mutational profile in lacI reporter gene is similar to those detected in human head and neck cancer, and p53 mutations were observed in mouse oral tumor tissues. Taken together, we conclude that the formation of diol epoxides plays a major role among the mechanisms by which DB[a,l]P exerts its oral mutagenicity and tumorigenicity.

Abstract 3792: WISP-1 increases cell migration and ICAM-1 expression in human oral squamous cell carcinomas.

Abstract Oral squamous cell carcinomas (OSCC) have a striking tendency to migration and metastasis to cervical lymph nodes. Wnt-1 induced secreted protein 1 (WISP-1) belongs to the CCN family (CTGF/CYR61/NOV), which is secreted cysteine-rich proteins. However, the effects of WISP-1 on migration and Intercellular adhesion molecule-1 (ICAM-1) expression in human OSCC are largely unknown. First, we found that the expression of WISP-1 in human OSCC tissues was higher than in normal oral tissues. We also demonstrated that WISP-1 enhanced cell migration and ICAM-1 up-regulation in human OSCC. Transfection of cells with ICAM-1 siRNA reduced WISP-1-mediated cell migration. WISP-1 activated αvβ3 integrin, ASK1, JNK/p38, c-Jun, and AP-1 signal transduction pathway, and WISP-1-induced expression of ICAM-1 and migration activity was inhibited by the αvβ3 antibody or inhibitor of ASK1, p38, JNK, and c-Jun. In addition, human OSCC were infected with lentivirus containing human WISP-1 shRNA which reduced the migratory ability and ICAM-1 expression. Over all, we characterized an important role for WISP-1 which regulates cell migratoin by increasing ICAM-1 expression in human OSCC via the αvβ3 integrin, ASK1, JNK/p38, c-Jun, and AP-1 signaling pathway. Citation Format: An-Chen Chang. WISP-1 increases cell migration and ICAM-1 expression in human oral squamous cell carcinomas. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3792. doi:10.1158/1538-7445.AM2013-3792

Abstract 3003: Aurora kinase A as a novel therapeutic target in oral squamous cell carcinoma.

Abstract Recent experiments have showed that it is possible to use pharmacological agents that inactivate oncogenes to treat at least some types of human malignancies. However, the development of molecular targeted therapy in oral squamous cell carcinoma (OSCC) is lagging behind compare to other cancers. In this study, we attempted to identify an appropriate target molecule and to determine whether targeting such a molecule is plausible therapeutic approach for the treatment of patients with OSCC. We determined the gene expression profiles of 9 human OSCC cell lines and non-neoplastic keratinocyte cell line by microarray analysis, and then identified Aurora kinase A (AURKA) as a cancer-related gene. AURKA has been shown to be related to the progression, survival, histological differentiation, and metastasis in various tumors. We revealed the overexpression of AURKA mRNA and protein in human OSCC cell lines and tissues. To clarify the function of AURKA in the cell proliferation of OSCC cells, we investigated the effect of small interfering RNA (siRNA) specific for AURKA (siAURKA) and MLN8237, an AURKA selective inhibitor, on the growth of human OSCC cells in vitro and in vivo. All siAURKAs almost completely suppressed the expression of AURKA protein, and significantly inhibited the growth of these cells compared to non-targeting siRNA. MLN8237 also markedly reduced the growth rate of human OSCC cells. Next, we assessed the growth inhibitory effect of siAURKA and MLN8237 using mouse model. Synthetic siAURKA/atelocollagen complexes (40 μM) were administrated into mouse tail vain every 3 days, and MLN8237 (20 mg/kg) was received orally for 14 consecutive days. We found both siAURKA and MLN8237 significantly reduced the size of subcutaneously xenografted OSCC tumors. To confirm the usefulness of targeting AURKA in OSCC, we attempted to culture the resected tumor tissues from 3 patients with OSCC and obtained primary cultured cells. Knockdown of AURKA expression and MLN8237 induced the growth inhibition of OSCC primary cultured cells. Furthermore, the expression of AURKA mRNA in OSCC tissues resected from patients was examined. In 37 of 50 primary OSCC tissues, the expression levels of AURKA mRNA were more than 2-fold increase compared to normal oral mucosa tissues, and notably we found significant association between AURKA mRNA expression levels and histological differentiation and lymph node metastasis. These results suggest that AURKA plays a critical role in the growth of human OSCC cells, and targeting AURKA appears to be a potentially useful therapeutic approach for patients with OSCC. Citation Format: Hiroshi Tanaka, Koh-ichi Nakashiro, Kazuki Iwamoto, Norihiko Tokuzen, Yohei Fujita, Rikimaru Shirakawa, Ryota Oka, Hiroyuki Goda, Hiroyuki Hamakawa. Aurora kinase A as a novel therapeutic target in oral squamous cell carcinoma. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3003. doi:10.1158/1538-7445.AM2013-3003

Abstract 4314: Loss of CYLD promotes cell migration through stabilized ALK5 in human oral squamous cell carcinoma cells.

Abstract Five-year survival of patients with oral squamous cell carcinoma (OSCC) has not changed apparently for the past 30 years. Although cylindromatosis (CYLD) is thought as a potent tumor suppressor, its biological significances in malignancies are largely unknown. The aim of this study was to clarify the role of CYLD in OSCC progression. We investigated expression of CYLD in OSCC including intraepithelial neoplasia (IEN; n = 48) and invasive carcinomas (n = 133) tissues and normal oral mucosal tissues (n = 35) by immunohistochemistry. In addition, effects of CYLD knockdown by siRNA or its overexpression on OSCC progression using OSCC cell lines. Our immunohistochemical analyses revealed that CYLD expression was significantly reduced at invasive lesions in OSCC tissues whereas it was conserved in normal epithelium and IEN. In addition, lower CYLD expression was associated with poor overall survival in invasive OSCC. Accordingly, CYLD knockdown led to acquisition of mesenchymal state and increased migratory activity in OSCC cells. Interestingly, loss of CYLD enhanced TGFβR1 (ALK5) protein expression by promoting ALK5 stability while overexpression of wild-type CYLD downregulated ALK5. Furthermore, EMT-like changes induced by CYLD knockdown were completely blocked by a TGFβR1 kinase inhibitor in OSCC cells. These findings suggest that downregulation of CYLD promotes invasion through EMT-like changes via ALK5 stabilization in OSCC cells. Further studies for these mechanisms probably provide new insights into the TGFβ signal transduction in cancer and development of a novel therapy in OSCC. Citation Format: Satoru Shinriki, Hirofumi Jono, Jian-Dong Li, Takuya Nakamura, Mitsuhiro Hayashi, Jianying Guo, Masanori Shinohara, Yukio Ando. Loss of CYLD promotes cell migration through stabilized ALK5 in human oral squamous cell carcinoma cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4314. doi:10.1158/1538-7445.AM2013-4314

Abstract 1987: Tumor suppressor ADAM23 mediates the HPV-associated carcinogenesis.

Abstract “High risk” human papillomaviruses (HPV) are known to cause or are closely associated with the development of human cervical, anal and some types of head and neck cancers. Integration of HPV DNA into host genome and subsequent expression of viral oncogenes, such as E6 and E7, are critical initial events for the HPV-associated cancer development; however, HPV infection alone is not sufficient to convert normal cells to malignant phenotypes, suggesting that other additional genetic and/or epigenetic events in the HPV-infected cells are required. The aim of the current study is to identify molecular determinants that are functionally linked to the pathogenesis of the HPV-associated cancers. We used HPV-16 harboring immortalized but non-transformed oral epithelial cells (HOK-16B), infected with high-throughput Decode RNAi lentiviral screening pools containing about 70,000 shRNAmir constructs capable of knocking down the target genes individually (3-4 constructs per gene), and selected them in DMEM-based high calcium/serum media in which HOK-16B cells are not permissive to survive. From the surviving colonies, we have identified several putative tumor suppressors including A Disintegrin and etalloproteinase domain-containing protein 23 (ADAM23). The function of ADAM23 was further validated such that singly knocking down in HOK-16B cells (HOK16B/ADAM23i) acquired proliferative potential in DMEM-based medium. HOK16B/ADAM23i cells also gained resistance to ionizing radiation (IR), cisplatin treatment, and differentiation as demonstrated by colonogenic assay, MTT assay, and the 3-dimensional raft culture systems, respectively. More importantly, the expression is largely diminished in squamous cell carcinoma (SCC) cell lines but more so in HPV-harboring SCC. We further found that ADAM23 expression is high in normal human oral epithelial tissues but low or none in HPV-positive OSCC tissue specimens as determined by immunohistochemical staining. Our data suggest that ADAM23 may play a role in development of HPV-associated cancers. Citation Format: Paul Yang, Drake W. Williams, Terresa Kim, Ki-Hyuk Shin, Mo Kang, No-Hee Park, Reuben H. Kim. Tumor suppressor ADAM23 mediates the HPV-associated carcinogenesis. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1987. doi:10.1158/1538-7445.AM2013-1987

Visual perception enhancement for detection of cancerous oral tissue by multi-spectral imaging

Color reproduction systems based on the multi-spectral imaging technique (MSI) for both directly estimating reflection spectra and direct visualization of oral tissues using various light sources are proposed. Images from three oral cancer patients were taken as the experimental samples, and spectral differences between pre-cancerous and normal oral mucosal tissues were calculated at three time points during 5-aminolevulinic acid photodynamic therapy (ALA-PDT) to analyze whether they were consistent with disease processes. To check the successful treatment of oral cancer with ALA-PDT, oral cavity images by swept source optical coherence tomography (SS-OCT) are demonstrated. This system can also reproduce images under different light sources. For pre-cancerous detection, the oral images after the second ALA-PDT are assigned as the target samples. By using RGB LEDs with various correlated color temperatures (CCTs) for color difference comparison, the light source with a CCT of about 4500 K was found to have the best ability to enhance the color difference between pre-cancerous and normal oral mucosal tissues in the oral cavity. Compared with the fluorescent lighting commonly used today, the color difference can be improved by 39.2% from 16.5270 to 23.0023. Hence, this light source and spectral analysis increase the efficiency of the medical diagnosis of oral cancer and aid patients in receiving early treatment.

Primary microcephaly gene MCPH1 shows signatures of tumor suppressors and is regulated by miR-27a in oral squamous cell carcinoma.

Mutations in the MCPH1 (microcephalin 1) gene, located at chromosome 8p23.1, result in two autosomal recessive disorders: primary microcephaly and premature chromosome condensation syndrome. MCPH1 has also been shown to be downregulated in breast, prostate and ovarian cancers, and mutated in 1/10 breast and 5/41 endometrial tumors, suggesting that it could also function as a tumor suppressor (TS) gene. To test the possibility of MCPH1 as a TS gene, we first performed LOH study in a panel of 81 matched normal oral tissues and oral squamous cell carcinoma (OSCC) samples, and observed that 14/71 (19.72%) informative samples showed LOH, a hallmark of TS genes. Three protein truncating mutations were identified in 1/15 OSCC samples and 2/5 cancer cell lines. MCPH1 was downregulated at both the transcript and protein levels in 21/41 (51.22%) and 19/25 (76%) OSCC samples respectively. A low level of MCPH1 promoter methylation was also observed in 4/40 (10%) tumor samples. We further observed that overexpression of MCPH1 decreased cellular proliferation, anchorage-independent growth in soft agar, cell invasion and tumor size in nude mice, indicating its tumor suppressive function. Using bioinformatic approaches and luciferase assay, we showed that the 3′-UTR of MCPH1 harbors two non-overlapping functional seed regions for miR-27a which negatively regulated its level. The expression level of miR-27a negatively correlated with the MCPH1 protein level in OSCC. Our study indicates for the first time that, in addition to its role in brain development, MCPH1 also functions as a tumor suppressor gene and is regulated by miR-27a.

Expression of Yes-associated protein 1 gene and protein in oral squamous cell carcinoma

Background Oral squamous cell carcinoma (OSCC) is one of the most common malignancies in the oral and maxillofacial region. Yes-associated protein 1 (YAP1) has been implicated as a bona fide oncogene in solid tumors. We seek to elucidate the role of YAP1 in OSCC tissue. Methods We identified YAP1 gene and protein overexpression in 30 OSCC patients and 10 normal oral mucosa tissues by immunohistochemistry, Western blotting and reverse transcription polymerase chain reaction (RT-PCR). Results In the normal oral mucosa by immunohistochemical staining, YAP1 mainly located in both the cytoplasm and nucleus mainly the nuclei of the basal cells. In OSCC, the expression of YAP1 translocated from the nucleus to cytoplasm; YAP1 being mainly located in both the cytoplasm and nucleus of the adjacent mucosa. The expression of YAP1 gradual increased in normal oral mucosa, tumor adjacent mucosa and low grade, middle grade, high grade OSCC tissue by Western blotting. Significant difference was found between the expressions of the normal oral mucosa and OSCC tissue (P &lt;0.05). The coincidence was detected between the normal oral mucosa and OSCC tissue by RT-PCR (P &lt;0.05). Conclusions YAP1 is involved in the carcinogenesis and development of OSCC. There is a transformation between nucleus and cytoplasm.

Overexpression of CDCA2 in Human Squamous Cell Carcinoma: Correlation with Prevention of G1 Phase Arrest and Apoptosis

Cell division cycle associated 2 (CDCA2) recruits protein phosphatase 1 to chromatin to antagonize activation of ataxia telangiectasia mutated (ATM)-dependent signal transduction. ATM kinase plays a critical role in the DNA damage response and its phosphorylation cascade to inhibit the p53-MDM2 interaction, which releases p53 to induce p21 and G1 cell-cycle arrest. However, the relevance of CDCA2 to human malignancy including oral squamous cell carcinoma (OSCC) is unknown. In the current study, we found that CDCA2 expression was up-regulated in OSCC cell lines. Functional studies with shRNA system showed that knockdown of CDCA2 significantly (P<0.05) inhibited cellular proliferation compared with the control cells by arresting cell-cycle progression at the G1 phase and up-regulating the cyclin-dependent kinase inhibitors (p21Cip1, p27Kip1, p15INK4B, and p16INK4A). CDCA2 knockdown also promoted apoptosis after treatment with the DNA damage reagent, cisplatin. In clinical samples, the CDCA2 protein expression level in primary OSCCs was significantly (P<0.05) greater than in matched normal oral tissues (67/85, 79%). Furthermore, CDCA2-positive cases were correlated significantly (P<0.05) with high cancer progression. Our results showed for the first time that CDCA2 frequently is overexpressed in OSCCs and might be associated closely with OSCC progression by preventing cell-cycle arrest and apoptosis.

Artefacts Produced by Normal Saline When Used as a Holding Solution for Biopsy Tissues in Transit

Oral surgeons, surgeons and dentists carrying out small biopsy procedures on an out-patient basis have been frequently sending poorly stored biopsy tissues to the Departments of Oral Pathology of various dental colleges, wherein the tissues were being stored in normal saline and then transferred to formalin. Such tissues often show abnormal cellular and architectural changes, which pose a challenge to diagnosis, especially when the histopathologist is not aware that the tissue was stored in normal saline for some time. We wanted to know the extent of artefactually induced cellular and architectural changes in tissues that were transported in normal saline and received by us, based on the duration for which they were held in normal saline. Normal oral soft tissue was subjected to storage in normal saline for periods varying from 1 to 36h, before being fixed in 10% formalin. Soft tissue specimens were collected during routine surgical extractions and each was cut into six parts. One was transferred immediately to formalin as control and other bits kept in normal saline for intervals of 1, 3, 12, 24, and 36h before fixing in formalin. A comparative photographic analysis was carried out to analyze the histopathological changes. The tissues kept in normal saline before fixation underwent various changes. In no way should normal saline be used, even for a short time, to store and transport excised tissue; it is imperative that such tissues be placed immediately in a proper fixative like 10% formalin.