Use of High-Frequency Ultrasound for the Correlation of Epithelial Rete Peg Variation.

OBJECTIVE: Rete pegs are projections of the oral epithelium into connective tissue. Their dimensions change during pathological conditions and may correlate with wound-healing status. Non-invasive, high-frequency ultrasound (US) may be able to capture these changes and aid in early detection of histopathological changes. The aim of this preclinical study is to correlate US images with histology and quantify epithelial layers at different tooth sites. METHODS: Sagittal B-mode images of mid-facial and interproximal oral soft tissue sites were recorded in a preclinical minipig model using a linear array in second harmonic mode (12/24 MHz). Histology samples from the same locations were stained (hematoxylin and eosin), digitized and registered with US images. Manual annotations were used to measure distances D1 (thickness of epithelium on histology vs. hyperechoic zone on US) and D2 (sum of epithelial thickness and length of rete pegs on histology vs. sum of hyperechoic and hypoechoic zone on US) to statistically analyze them. RESULTS: Ultrasonic-derived dimensions yielded a mean bias of -0.64 (55% coefficient of variance [COV]: -180 to +180 µm) and -12 µm (39% COV: -260 to +240 µm) for D1 and D2, respectively. Individualized analysis of D1 and D2 by tooth type showed similar tends in the ability to differentiate between epithelium at different tooth locations, on both histology and US. CONCLUSION: Assessing soft tissue dimensions on a sub-millimeter scale using clinical imaging hardware is still a developing area. Future research might open doors for diagnosis of oral pathologies and abnormal wound healing, and may limit false-positive indications for biopsies.

Ultrasonography-Derived Elasticity Estimation of Live Porcine Oral Mucosa.

OBJECTIVES: To investigate the biomechanical properties of porcine oral tissues with in vivo ultrasonography and to compare the difference between oral alveolar mucosa and gingival tissue concerning compressional and tensile mechanical strain. MATERIALS AND METHODS: Sinclair minipigs (6 females and 4 males, 6 to 18 months of age) were anesthetized for ultrasonography. In vivo high-frequency tissue harmonic ultrasound (12/24 MHz) cine-loops were obtained while inducing mechanical tissue stress (0 to 1 N). Post-processing strain analysis was performed in a cardiac speckle tracking software (EchoInsight®). Region of interest (ROI) was placed for gingival and alveolar mucosa tissues for longitudinal (compressional) and tensile strain analyses. A calibrated gel pad was employed to determine the absolute force (pressure) for the measured tissue strain response function. The resulting elasticity data was statistically analyzed using custom Matlab scripts. RESULTS: In total, 38 sonography cine-loops around the third premolars were included in the investigation. The longitudinal strain of alveolar mucosa ε AM L was found to be significantly (P < .05) larger than that of gingiva ε G L . Across the measured force range, ε AM L ~ 1.7 × Îµ G L . Significant differences between alveolar mucosa and gingiva tissues were found for all forces. The tensile strain of the alveolar mucosa ε AM T was found to be ~2 × Îµ G T (on the epithelial surface of the gingiva). Both were statistically significantly different for forces exceeding ~0.08 N. At depth, that is, 500 and 1000 µm below the epithelial surface, the gingiva was found to have less ability to stretch contrary to the alveolar mucosa. Gingival tissue at 500 µm depth has significantly less tensile strain than at its surface and more than at 1000 µm depth. In contrast, the tensile strain of alveolar mucosa is largely independent of depth. CONCLUSION: Ultrasonography can reveal significant differences in oral alveolar mucosal and gingival elastic properties, such as compressional and tensile strain. Under minute forces equivalent to 10 to 40 g, these differences can be observed. As dental ultrasound is a chairside, and noninvasive modality, obtaining real-time images might soon find clinical utility as a new diagnostic tool for the objective and quantitative assessment of periodontal and peri-implant soft tissues in clinical and research realms. As ultrasound is a safe modality with no known bioeffects, longitudinal monitoring of areas of concern would be particularly attractive.

Using PDX animal models to identify and stratify adenoid cystic carcinoma patients presenting an enhanced response to HDAC inhibitors.

Adenoid cystic carcinoma (ACC) patients face a highly infiltrative and metastatic disease characterized by poor survival rates and suboptimal response to available therapies. We have previously shown that sensitization of ACC tumors to chemotherapy using histone deacetylase inhibitors (HDACi) constitutes a promising therapeutic strategy to manage tumor growth. Here, we used patient-derived xenografts (PDX) from ACC tumors to evaluate the effects of in vivo administration of the HDAC inhibitor Entinostat combined with Cisplatin over tumor growth. RNA from PDX tumor samples receiving the proposed therapy were analyzed using NanoString technology to identify molecular signatures capable of predicting ACC response to the therapy. We also used an RNAseq dataset from 68 ACC patients to validate the molecular signature identified by the NanoString platform. We found that the administration of Entinostat combined with Cisplatin resulted in a potent tumor growth inhibition (TGI) ranging from 38% to 106% of the original tumor mass. Enhanced response to therapy is consistent with the reactivation of tumor suppressor genes, including SFRP1, and the downregulation of oncogenes like FGF8 and CCR7. Nanostring data from PDX tumors identified a genetic signature capable of predicting tumor response to therapy. We further stratified 68 ACC patients containing RNAseq data accordingly to the activity levels of the identified genetic signature. We found that 23% of all patients exhibit a genetic signature consistent with a high ACC tumor response rate to Entinostat and Cisplatin. Our study provides compelling preclinical data supporting the deployment of a powerful systemic anticancer therapy crafted and explicitly tested for ACC tumors.

Interproximal implant thread exposure after initial bone remodeling as a risk indicator for peri-implantitis.

BACKGROUND: Due to the clinical challenges involved in successfully treating peri-implantitis, it is imperative to identify patient- and implant-level risk factors for its prevention. The main goal of this retrospective longitudinal radiographic and clinical study was to investigate whether interproximal radiographic implant thread exposure after physiological bone remodeling may be a risk factor for peri-implantitis. The secondary goal was to evaluate several other potential risk indicators. METHODS: Of 4325 active dental school patients having implants placed, 165 partially edentulous adults (77 men, 88 women) aged 30-91 with ≥2 years of follow-up upon implant restoration were included. Implants with ≥1 interproximal thread exposed (no bone-to-implant contact) (n = 98, 35%) constituted the test group and those without exposed threads (n = 182, 65%) the control group. Descriptive, binary, and multivariate regression analyses were evaluated for goodness of fit. Wald tests were used to evaluate for significance set at 0.05. RESULTS: Of the 280 implants (98 test, 182 control), 8 (2.9%) failed over a mean follow-up period of 7.67 (±2.63) years, and 27 implants (19 test, 8 control) developed peri-implantitis, with the exposed group having eight-fold (7.82 times) adjusted greater odds than the non-exposed. The risk increased four-fold (3.77 times) with each thread exposed. No other patient- or implant-related potentially confounding risk factors were identified. CONCLUSIONS: Exposed interproximal implant threads after physiologic bone remodeling may be an independent risk indicator for incident peri-implantitis. Hence, clinicians should closely monitor patients with implant threads that have no bone-to-implant contact for incident peri-implantitis.

Curcuma longa L. Effects on Akt/mTOR Pathway and NF-κB Expression During Skin Wound Healing: An Immunohistochemical Study.

Skin ulcers, wounds, or burns represent a burden for health care worldwide. Our aim was to explore the effects of mucoadhesive formulation with Curcuma longa L. extract mucoadhesive formulation containing curcumin (MFC) on skin healing in Wistar rats. Fifty-four rats were randomly allocated into 3 groups: control, vehicle, and MFC. A full-thickness circular wound was induced on the back of each animal. Two daily applications of the products were performed according to the experimental group. On days 3, 10, and 21, 6 animals in each group were euthanized. Clinical analysis was based on wound area. Histologic analysis was performed in hematoxylin and eosin-stained sections, with re-epithelization and inflammation being assessed by means of semiquantitative scores. To analyze the Akt/mTOR pathway, immunohistochemistry for phospho Akt (pAkt) and phospho ribosomal protein S6 were investigated. In addition, nuclear factor kappa-light-chain-enhancer of activated B cells immunolabeling was performed. Clinical analysis revealed wounds with a smaller area on days 3 and 10 in curcumin-treated animals. Histologically, MFC had a significant impact on inflammatory events on days 3 and 10 and promoted faster re-epithelization, which was evidenced on day 10. MFC-treated wounds exhibited pAkt upregulation on day 10 and both pAkt and phospho ribosomal protein S6 downregulation on day 21. Nuclear factor kappa-light-chain-enhancer of activated B cells expression varied through the evaluation periods; however, no significant difference was observed between groups. Collectively, our results indicate that MFC is efficient in accelerating cutaneous wound repair through modulation of the inflammatory process and stimulus of re-epithelization by an Akt/mTOR-dependent mechanism.

The impact of photobiomodulation therapy on the biology and behavior of head and neck squamous cell carcinomas cell lines.

Photobiomodulation therapy (PBMT) is an emerging therapeutic modality designed to prevent and treat chemotherapy-driven oral mucositis (OM). However, the response of tumor cells to the effects of PBMT remains poorly understood. Our study explores the effects of PBMT in head and neck squamous cell carcinoma (HNSCC) based on cellular proliferation, migration, and survival of tumor cells and its population of cancer stem cells (CSC). We explored the behavior of two HNSCC cell lines (HN6 and HN13) under two distinct conditions, a physiological growing condition (10% FBS), and under stress growing condition (2% FBS) prior to irradiation using diode laser (InGaAlP; MM Optics, São Carlos, SP, Brazil). Diode laser (660 nm) was applied with a power of 100 mW delivering a total energy per point of 0.24 J. MTT and wound healing test (scratch assay) were performed to evaluate, respectively, proliferation and migration of tumor cells. Clonogenic and spheres formation assays were also performed to evaluate the survival and percentage of CSC upon irradiation. Overall, we observed that PBMT does not exacerbate the behavior of HNSCC. We could only observe a decrease in cellular proliferation of one cell line (HN6) when cultured under nutritional stress conditions (p < .05). There were no significant differences between the control and the PBMT groups regarding cell migration, survival and the percentage of CSC. Collectively, our results suggest that in vitro administration of PBMT to HNSCC does not modify the behavior of tumor cells.

Pharmacological PTEN inhibition: potential clinical applications and effects in tissue regeneration.

Although the human body can heal, it takes time, and slow healing and chronic wounds often occur. Thus, identifying novel therapies to aid regeneration is needed. Here, we conducted a systematic review following the Preferred Reporting Items for Systematic Reviews guidelines and assessed preclinical studies on phosphatase and tensin homolog (PTEN) inhibitors and their effects on tissue repair and regeneration. In conditions associated with neurodegeneration, tissue injury and ischemia, the PTEN-regulated PI3K/AKT signaling pathway is activated. The use of PTEN inhibitors resulted in better tissue response by reducing the healing time and lesion sizes or inducing neuronal regeneration. Notably, all studies included in this systematic review indicated that pharmacological inhibition of PTEN enhanced the repair process of the eye, lung, muscle and nervous system.

BMAL1 Modulates Epidermal Healing in a Process Involving the Antioxidative Defense Mechanism.

The circadian rhythm regulates the physiology and behavior of living organisms in a time-dependent manner. Clock genes have distinct roles including the control over gene expression mediated by the transcriptional activators CLOCK and BMAL1, and the suppression of gene expression mediated by the transcriptional repressors PER1/2 and CRY1/2. The balance between gene expression and repression is key to the maintenance of tissue homeostasis that is disrupted in the event of an injury. In the skin, a compromised epithelial barrier triggers a cascade of events that culminate in the mobilization of epithelial cells and stem cells. Recruited epithelial cells migrate towards the wound and reestablish the protective epithelial layer of the skin. Although we have recently demonstrated the involvement of BMAL and the PI3K signaling in wound healing, the role of the circadian clock genes in tissue repair remains poorly understood. Here, we sought to understand the role of BMAL1 on skin healing in response to injury. We found that genetic depletion of BMAL1 resulted in delayed healing of the skin as compared to wild-type control mice. Furthermore, we found that loss of Bmal1 was associated with the accumulation of Reactive Oxygen Species Modulator 1 (ROMO1), a protein responsible for inducing the production of intracellular reactive oxygen species (ROS). The slow healing was associated with ROS and superoxide dismutase (SOD) production, and pharmacological inhibition of the oxidative stress signaling (ROS/SOD) led to cellular proliferation, upregulation of Sirtuin 1 (SIRT1), and rescued the skin healing phenotype of Bmal1-/- mice. Overall, our study points to BMAL1 as a key player in tissue regeneration and as a critical regulator of ROMO1 and oxidative stress in the skin.

Effects of a mucoadhesive formulation containing Curcuma longa L. on oral wound healing

Introduction: The aim of this study was to investigate the effects of a topical mucoadhesive formulation with Curcuma longa L. extract (MFC) on oral wound healing. Methods: Seventy-two Wistar rats were randomly assigned to 3 groups: Control, Vehicle, and MFC. Traumatic ulcers were made on the dorsum of the tongue with a 3-mm diameter punch. Vehicle and MFC groups received application of the products twice a day, while animals in the control group were cared for in identical conditions but received no product application. Six rats in each group were euthanized at days 3, 5, 10, and 14. Percentage of repair was calculated based on wound area. HE-stained histological sections were obtained for semi-quantitative analysis of re-epithelization and inflammation. Results: Clinical findings revealed that at days 3 and 5, animals from the MFC group exhibited a significantly higher percentage of wound repair. At day 5, animals from this group also demonstrated a significant increase in the degree of re-epithelization and inflammation. Conclusions: MFC is capable of accelerating oral wound repair in an in vivo model by modulating the inflammatory process and stimulating epithelial proliferation. (AU)

Hypoxic niches are endowed with a protumorigenic mechanism that supersedes the protective function of PTEN.

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common malignancy worldwide and is characterized by a fast-paced growth. Like other solid tumors, the HNSCC growth rate results in the development of hypoxic regions identified by the expression of hypoxia-inducible factor 1α (HIF-1α). Interestingly, clinical data have shown that pharmacological induction of intratumoral hypoxia caused an unexpected rise in tumor metastasis and the accumulation of cancer stem cells (CSCs). However, little is known on the molecular circuitries involved in the presence of intratumoral hypoxia and the augmented population of CSCs. Here we explore the impact of hypoxia on the behavior of HNSCC and define that the controlling function of phosphatase and tensin homolog (PTEN) over HIF-1α expression and CSC accumulation are de-regulated during hypoxic events. Our findings indicate that hypoxic niches are poised to accumulate CSCs in a molecular process driven by the loss of PTEN activity. Furthermore, our data suggest that targeted therapies aiming at the PTEN/PI3K signaling may constitute an effective strategy to counteract the development of intratumoral hypoxia and the accumulation of CSCs.-Nascimento-Filho, C. H. V., Webber, L. P., Borgato, G. B., Goloni-Bertollo, E. M., Squarize, C. H., Castilho, R. M. Hypoxic niches are endowed with a protumorigenic mechanism that supersedes the protective function of PTEN.

Interference with the bromodomain epigenome readers drives p21 expression and tumor senescence.

Head and neck cancer (HNSCC) are one of the most common solid malignancies of the world, being responsible for over 350,000 deaths every year. Much of the complications in managing and treating HNSCC advent from the complex genetic and epigenetic landscape of the disease. Emerging information has shown promising results in targeting BRD4, an epigenetic regulator bromodomain that functions as a scaffold for transcription factors at promoters and super-enhancers. Here we show that by disrupting the interaction between BRD4 and histones using the bromodomain inhibitor JQ1, HNSCC cells undergo cell growth arrest followed by cellular senescence. Mechanistically, JQ1 negatively impacted the phosphorylation levels of SIRT1 along with the acetylation levels of mutant p53 (active). In vivo administration of JQ1 resulted in disruption of HNSCC growth along with the activation of cellular senescence, observed by the accumulation of DNA double-strand breaks, p16ink4, accumulation of senescence-associated beta-galactosidase, and loss of phosphorylated Sirt1ser47. Furthermore, we also demonstrate that JQ1 was efficient in reducing the population of cancer stem cells from HNSCC xenografts.

Photobiomodulation therapy modulates epigenetic events and NF-κB expression in oral epithelial wound healing.

The aim of this study was to evaluate the effect of photobiomodulation therapy (PBMT) on histone 3 acetylation (acH3) and NF-κB expression during oral ulcer healing. A total of 48 male Wistar rats were divided into control group (CG) and PBMT group (n = 24 each). Traumatic ulcers were created in the dorsum of the rats' tongue with a punch tool. Irradiation with InGaAlP laser, 660 nm, 40 mW, 0.04 cm2 spot size, 4 J/cm2, 4 s, and 0.16 J per spot was performed once a day in close contact for 10 consecutive days. CG received only daily handling. Rats were euthanized on days 3, 5, and 10 (n = 8) and were monitored daily to assess wound status. Immunohistochemical analysis for acH3 and NF-κB detection was performed. One thousand epithelial cells were counted, and mean acH3- and NF-κB-positive cells were calculated and compared between the groups. PBMT accelerated the repair of oral ulcers. On day 3, PBMT showed significantly higher means for acH3- and NF-κB-positive cells than CG. On day 5, no difference was observed between the groups concerning both markers. On day 10, PBMT presented lower acH3 and NF-κB means than the control group. We concluded that PBMT stimulates keratinocyte migration in the early stage of oral wound healing and keratinocyte differentiation at the final stage by modulating histone acetylation and NF-κB expression.

Interfering with bromodomain epigenome readers as therapeutic option in mucoepidermoid carcinoma.

PURPOSE: Emerging evidence indicates that bromodomains comprise a conserved class of epigenome readers involved in cancer development and inflammation. Bromodomains are associated with epigenetic modifications of gene transcription through interactions with lysine residues of histone tails. Particularly, the bromodomain and extra-terminal domain (BET) family member BRD4 has been found to be involved in the control over oncogenes, including c-MYC, and in the maintenance of downstream inflammatory processes. The objective of this study was to evaluate the effect of pharmacologically displacing BRD4 in mucoepidermoid carcinoma (MEC) cells. METHODS: We assessed the presence of BRD4 levels in a panel of human MEC tissue samples in conjunction with histological grading and clinical information. In vitro studies were carried out using human MEC-derived cell lines. The BET inhibitor iBET762 was administered to MEC cells to assess the impact of disrupted BRD4 signaling on colony forming capacities and cell cycle status. The activation of cellular senescence induced by iBET762 was determined by immunohistochemical staining for p16ink4. Flow cytometry was used to identify populations of cancer stem cells in MEC-derived cell lines. RESULTS: We found that primary human MECs and MEC-derived cell lines are endowed with high BRD4 expression levels compared to those in normal salivary glands. We also found that, by displacing BRD4 from chromatin using the BET inhibitor iBET762, MEC cells lose their colony forming capacities and undergo G1 cell cycle arrest and senescence. Finally, we found that targeted displacement of BRD4 from chromatin results in depletion of cancer stem cells from the overall MEC cell populations. CONCLUSIONS: Our findings indicate that bromodomain-mediated gene regulation constitutes an epigenetic mechanism that is deregulated in MEC cells and that the use of BET inhibitors may serve as a feasible therapeutic strategy to manage MECs.

TGF-ß1 and its association with clinicopathological features, proliferative activity and prognosis in oral squamous cell carcinoma: an immunohistochemical study

Introduction: The prognostic value of transforming growth factor beta-1 (TGF-ß1) in oral cancer remains unclear. Therefore, the aim of this study was to evaluate TGF-ß1 expression in oral squamous cell carcinoma (OSCC) samples and its association with clinicopathological data, tumor proliferative activity, and patients' prognosis. Methods: A total of 68 patients with histopathological diagnosis of OSCC were included, as well as 9 cases of normal oral mucosa for comparison purposes. The OSCC sample was categorized according to patients' outcomes in favorable prognosis (n=30) or unfavorable prognosis (n=38). Immunohistochemical staining for TGF-ß1 and Ki-67 were performed. The slides were semi-quantitatively and quantitatively evaluated for TGF-ß1 and Ki-67, respectively. Results: TGF-ß1 was significantly increased in OSCC compared to normal oral mucosa (<0.01). An inverse correlation was found between TGF-ß1 and Ki67 staining in OSCC (p=0.01). No association was found between TGF-ß1 expression and OSCC clinicopathological features, prognosis or survival. Conclusions: TGF-ß1 had no prognostic value and appears to maintain its suppressive role concerning cell proliferation. (AU)

Effects of Copaiba Oil Topical Administration on Oral Wound Healing.

The effects of topical copaiba oil extract and topical corticosteroid were assessed on oral wound healing in an in vivo model using 96 male Wistar rats. Traumatic ulcers were caused in the dorsum of the tongue using a 3-mm punch tool. The animals were divided into: Control; Corticosteroid; Placebo and Copaiba oil Group. The animals received two daily applications of the products. The control group received only daily handling. Six rats in each group were euthanized at days 3, 5, 10 and 14. The animals were monitored daily to determine wound status. The weigh was assessed at day 0 and euthanasia day. The percentage of repair was calculated, and histopathological aspects were analyzed. The Kruskal-Wallis test was used to compare the results between groups and times of evaluation. Closing time was assessed through the log-rank test. The corticosteroid group lost more weight at days 10 and 14 than the control group (p < 0.05). Moreover, the healing time of corticosteroid group was longer than the control group (p = 0.007). No differences were observed between the copaiba oil group and the control group. We concluded that topical copaiba oil, in spite of being safe, did not accelerate the process of oral wound healing. Copyright © 2017 John Wiley & Sons, Ltd.

Copaiba oil-resin (Copaifera reticulata Ducke) modulates the inflammation in a model of injury to rats' tongues.

BACKGROUND: The regeneration of integrity and tissue homeostasis after injury is a fundamental property and involves complex biological processes fully dynamic and interconnected. Although there are medications prescribed to accelerate the process of wound healing by reducing the exaggerated inflammatory response, comes the need to search for different compounds of Amazonian biodiversity that can contribute to the acceleration of the healing process. Among these products, the copaiba oil-resin is one of the most prominent feature in this scenario, as they have been reported its medicinal properties. METHODS: Aiming to evaluate the anti-inflammatory and healing effect of copaiba oil-resin (Copaifera reticulata Ducke) in transfixing injury of rats' tongues first proceeded up the copaiba oil-resin oral toxicity test in 5 male mice to stipulate the therapeutic dose which was established at 200 mg/kg/day. Then it was induced transfixing injury in a total of 15 Wistar rats. The animals were randomly divided into three groups based on the treatment: control group, dexamethasone group and copaiba oil-resin group. After 7 days of treatment, histological slides stained with hematoxylin and eosin was prepared. Immunohistochemistry for CD68 (macrophage marker) was performed and analyzed by the cell counter Image J. RESULTS: The acute toxicity test showed that the oil-resin copal has low toxicity. Furthermore, copaiba oil-resin therapy modulates the inflammatory response by decreasing the chronic inflammatory infiltrate, edema and specifically the number of macrophages. CONCLUSIONS: The results indicate the potential of the Amazon region and showed up relevant because therapy with this extract modulates the inflammatory process.

Bryne's grading system predicts poor disease-specific survival of oral squamous cell carcinoma: a comparative study among different histologic grading systems.

OBJECTIVES: The aim of this study was to access the prognostic value of 4 histopathologic grading systems of oral squamous cell carcinoma (OSCC): The World Health Organization (WHO), Anneroth, Bryne (1989), and Bryne (1992). STUDY DESIGN: Eighty-five cases of OSCC diagnosed between 1996 and 2010 at the Clinics Hospital of Porto Alegre (Porto Alegre, Brazil) were included. Slides stained with hematoxylin and eosin were obtained, and a histologic grade was assigned on the basis of the consensus of 3 expert oral pathologists, who were blinded to the clinicopathologic factors. Each system was correlated with proliferative labeling index, accessed through Ki67 immunostaining, clinicopathologic factors, patient outcome (alive or deceased), and survival time. RESULTS: The increase in Bryne (1992) histologic grades was accompanied by an increase in proliferative labeling index. Moreover, this system was the only one associated with patient outcome (P = .01) and survival. Bryne (1992) grading system grade III tumors were associated with poor disease-specific survival according to univariate and multivariate cox regression analyses and the log-rank test (P < .05). The other systems evaluated presented no association with patients' outcome or survival. CONCLUSIONS: The Bryne (1992) grading system is more effective in predicting survival in OSCC compared with the systems proposed by the WHO, Anneroth, or Bryne (1989).

Hypoacetylation of acetyl-histone H3 (H3K9ac) as marker of poor prognosis in oral cancer.

AIMS: Epigenetics refers to changes in cell characteristics that occur independently of modifications to the DNA sequence. Oral carcinogenesis is influenced by modifications in epigenetic mechanisms, including changes in histones, which are proteins that support chromatin remodelling for the dynamic regulation of gene expression and silencing. The dysregulation of histone acetylation can lead to the uncontrolled activity of different genes, thereby triggering events associated with malignant transformation. The aim of this study was to analyse the expression of acetyl-histone H3 at lys9 (H3K9ac) in oral leucoplakia (OL) and oral squamous cell carcinoma (OSCC) in addition to its association with cell proliferation, epithelial-mesenchymal transition (EMT) and clinical-pathological findings. METHODS AND RESULTS: Samples of normal oral mucosa (NOM), OL and OSCC were submitted to immunohistochemical analysis using anti-H3K9ac, Ki67 and vimentin. Slides were submitted to quantitative analysis regarding the percentage of positive cells. OSCC presented less expression of H3K9ac in comparison to OL (P < 0.01), whereas Ki67 and vimentin levels increased from OL to OSCC (P < 0.001 and P = 0.03, respectively). OSCC patients with poor prognosis had less H3K9ac expression (P = 0.04). The Kaplan-Meier cumulative survival curves also revealed lower survival rates in patients with less H3K9ac expression (P < 0.01). CONCLUSIONS: The present findings suggest that changes in H3K9ac occur during the process of oral carcinogenesis along with an increase in cell proliferation and EMT. The results demonstrate that H3K9ac may be a useful novel prognostic marker for OSCC.

Overcoming adaptive resistance in mucoepidermoid carcinoma through inhibition of the IKK-ß/IκBα/NFκB axis.

Patients with mucoepidermoid carcinoma (MEC) experience low survival rates and high morbidity following treatment, yet the intrinsic resistance of MEC cells to ionizing radiation (IR) and the mechanisms underlying acquired resistance remain unexplored. Herein, we demonstrated that low doses of IR intrinsically activated NFκB in resistant MEC cell lines. Moreover, resistance was significantly enhanced in IR-sensitive cell lines when NFκB pathway was stimulated. Pharmacological inhibition of the IKK-ß/IκBα/NFκB axis, using a single dose of FDA-approved Emetine, led to a striking sensitization of MEC cells to IR and a reduction in cancer stem cells. We achieved a major step towards better understanding the basic mechanisms involved in IR-adaptive resistance in MEC cell lines and how to efficiently overcome this critical problem.