Tumor microenvironment and Oral Squamous Cell Carcinoma: A crosstalk between the inflammatory state and tumor cell migration.

OBJECTIVES: To analyze the inflammatory millieu in oral squamous cell carcinoma (OSCC) tumors and the influence of macrophages related-cytokines on the tumor cell migration. MATERIALS AND METHODS: Inflammatory protein profile and macrophage population (M2/M1 ratio) of human OSCC fragments were analyzed by proteomic analysis and flow cytometry assay respectively. To evaluate the effects of inflammation on OSCC behavior, we analyzed the role of polarized macrophages and cytokines (IL-6, IL-1ß and TNF-α) on OSCC cell lines (SCC25 and Cal27) responsiveness by western blotting (cell signaling) and time-lapse (cell migration). Also, it was addressed the crosstalk of IL-6-STAT3 axis with cell migration signaling using a STAT3 inhibitor (Stattic®) and a pull down assay for the RhoGTPase Rac1 activity. RESULTS: It was observed a ~2 fold predominance of M2 over M1 macrophages and a pro-inflammatory state in OSCC fragments. The M2 conditioned media increased migration speed and directionality of highly invasive OSCC cells (SCC25). OSCC cell lines were responsive to cytokine stimuli (IL6, IL-1ß and TNF-α), but only IL-6 increased migration properties of OSCC cells. This effect was dependent on STAT3-phosphorylation levels, which interfered with Rac1 activation levels. CONCLUSION: Our results suggest that the inflammatory milieu might favor invasion and metastasis of OSCC by the direct effect of macrophage-related cytokines on tumor migration.

Intracardiac Injection of Dental Pulp Stem Cells After Neonatal Hypoxia-Ischemia Prevents Cognitive Deficits in Rats.

Neonatal hypoxia-ischemia (HI) is associated to cognitive and motor impairments and until the moment there is no proven treatment. The underlying neuroprotective mechanisms of stem cells are partially understood and include decrease in excitotoxicity, apoptosis and inflammation suppression. This study was conducted in order to test the effects of intracardiac transplantation of human dental pulp stem cells (hDPSCs) for treating HI damage. Seven-day-old Wistar rats were divided into four groups: sham-saline, sham-hDPSCs, HI-saline, and HI-hDPSCs. Motor and cognitive tasks were performed from postnatal day 30. HI-induced cognitive deficits in the novel-object recognition test and in spatial reference memory impairment which were prevented by hDPSCs. No motor impairments were observed in HI animals. Immunofluorescence analysis showed human-positive nuclei in hDPSC-treated animals closely associated with anti-GFAP staining in the lesion scar tissue, suggesting that these cells were able to migrate to the injury site and could be providing support to CNS cells. Our study evidence novel evidence that hDPSC can contribute to the recovery following hypoxia-ischemia and highlight the need of further investigation in order to better understand the exact mechanisms underlying its neuroprotective effects.

NADPH-oxidase-derived ROS alters cell migration by modulating adhesions dynamics.

BACKGROUND INFORMATION: Cell migration requires the coordinated activation of structural and signalling molecules, such as the RhoGTPase Rac1. It is known that the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase complex assembly, which generates reactive oxygen species (ROS) at the cell membrane, also relies on Rac1 activation, indicating a possible effect of ROS during cell migration. In this study, we evaluated the effect of NADPH-oxidase-derived ROS on the migration process. RESULTS: Using time-lapse videos of CHO.K1 cells plated on fibronectin (2 µg/ml) or collagen (5 µg/cm2 ), we observed that depletion of ROS by N-acetyl-cysteine (NAC, 10 mM), an unspecific antioxidant, or diphenyliodonium (DPI, 10 µM), a NADPH-oxidase inhibitor, induced a ∼50% decrease in migration speed and severely impacted migration directionality. Then, we analysed the effects of NADPH oxidase on three migratory events: protrusion rate, adhesion process and signalling pathways related to cell migration. DPI induced an increase of ∼3 protrusion/cell, which were 2× faster but had a ∼50% retraction when compared with control. By pull-down assay, we observed no changes on Rac1 activation, indicating that ROS-mediated effects were related to downstream molecules, such as adhesion-related molecules. A reduction of the adhesion marker FAK-Y397 levels in cells treated with NAC and DPI was observed. In order to analyse adhesion dynamics, CHO.K1 cells transfected with paxillin-GFP analysed with total internal reflectance fluorescence (TIRF) indicated that DPI (5 µM) induced larger adhesions when compared with control. CONCLUSION: These results indicate that the local generation of NADPH-oxidase-derived ROS can modulate cell migration due to changes on adhesion dynamics and signalling. SIGNIFICANCE: This study highlights the physiological requirement of ROS for cell migration and the potential use of these molecules as targets to modulate the cell migration process at different diseases.

Effects of diabetes and hypertension on oral mucosa and tgfß1 salivary levels

Abstract The aim of this study was to investigate salivary levels of TGFβ1 and proliferation/ maturation of epithelial mucosa cells in diabetic and hypertensive patients. Design: in this cross-sectional study, whole stimulated saliva and oral mucosa exfoliative cytology specimens were collected from 39 patients that were healthy (control, n=10) or presented history of arterial hypertension (HAS, n=9), diabetes mellitus (DM, n=10) or both (DM+HAS, n=10). Salivary flow rate (SFR), TGFβ1 level in saliva, AgNORs and the epithelial maturation were evaluated. Non-parametric Kruskal-Wallis test, followed by Dunn's multiple comparison post-test and the Spearman test correlation analysis were used. SFR showed a significant decreased in DM and DM+HAS (0.47±0.11 and 0.64±0.43 mL/min) when compared to control (1.4±0.38 mL/min). DM+HAS presented the highest value of TGFβ1 concentration (24.72±5.89 pg/mL). It was observed a positive correlation between TGFβ1 and glycaemia (R=0.6371; p<0.001) and a negative correlation between TGFβ1 and saliva (R=-0.6162; p<0.001) and glycaemia and SFR (R=-0.5654; P=0.001). AgNORs number and status of maturation of mucosa cells were similar for all conditions. DM and DM+HAS presented the lowest SFR, which correlated with increased TGFβ1 levels. Despite the higher TGFβ1 secretion it was not observed changes in the morphology or proliferation of epithelial cells when diabetes or hypertension was present.

Resumo O objetivo deste estudo foi investigar os níveis de TGFβ1 na saliva e a proliferação/maturação das células epiteliais da mucosa em paciente diabéticos e hipertensos. Neste estudo transversal, saliva estimulada e amostras de citologia exfoliativa de mucosa oral foram coletadas de um total de 39 pacientes que se apresentavam saudáveis (controle, n=10) ou com história de hipertensão arterial (HAS, n=9), diabetes mellitus (DM, n=10) ou ambos (DM+HAS, n=10). Taxa de fluxo salivar (SFR), níveis de TGFβ1 na saliva, AgNORs e maturação epitelial foram avaliados. Teste não-paramétrico de Kruskal-Wallis, seguido de comparação múltipla de Dunn e correlação de Spearman foram utilizados para as análises. SFR diminuiu significantemente em DM e DM+HAS (0,47±0,11 e 0,64±0,43 mL/min) quando comparado ao controle (1,4±0,38 mL/min). DM+HAS apresentou os maiores valores de concentração de TGFβ1 (24,72±5,89 pg/mL). Foi observada uma correlação positiva entre TGFβ1 e glicemia (R=0,6371; p<0,001) e uma correlação negativa entre TGFβ1 e saliva (R=-0,6162; p<0,001) e glicemia e SFR (R=-0,5654; p=0,001). Número de AgNORs e o padrão da maturação das células epiteliais foram similares entre os todos grupos. DM e DM+HAS apresentaram os menores valores de SFR, os quais foram correlacionados com o aumento nos níveis de TGFβ1. Apesar da maior secreção de TGFβ1, não foram observadas mudanças na morfologia ou proliferação das células epiteliais quando o paciente apresentava diabetes ou hipertensão.

Low Doses of Curcuma longa Modulates Cell Migration and Cell-Cell Adhesion.

Cell invasion and metastasis are involved in clinical failures in cancer treatment, and both events require the acquisition of a migratory behavior by tumor cells. Curcumin is a promising natural product with anti-proliferative activity, but its effects on cell migration are still unclear. We evaluated the effects of curcumin on the proliferation, apoptosis, migration, and cell-cell adhesion of keratinocyte, oral squamous cell carcinoma (OSCC), and fibroblast cell lines, as well as in a xenograft model of OSCC. Curcumin (2 µM) decreased cell proliferation in cell lines with mesenchymal characteristics, while cell death was detected only at 50 µM. We observed that highly migratory cells showed a decrease on migration speed and directionality when treated with 2 or 5 µM of curcumin (50% and 40%, respectively, p < 0.05). Using spheroids, we observed that curcumin dose dependently decreased cell-cell adhesion, especially on tumor-derived spheroids. Also, in a xenograft model with patient-derived OSCC cells, the administration of curcumin decreased tumor growth and aggressiveness when compared with untreated tumors, indicating the potential antitumor effect in oral cancer. These results suggest that lower doses of curcumin can influence several steps involved in tumorigenesis, including migration properties, suggesting a possible use in cancer therapy. Copyright © 2017 John Wiley & Sons, Ltd.

Aging process alters hippocampal and cortical secretase activities of Wistar rats.

A growing body of evidence has demonstrated amyloid plaques in aged brain; however, little attention has been given to amyloid precursor protein (APP) processing machinery during the healthy aging process. The amyloidogenic and non-amyloidogenic pathways, represented respectively by ß- and α-secretases (BACE and TACE), are responsible for APP cleavage. Our working hypothesis is that the normal aging process could imbalance amyloidogenic and non-amyloidogenic pathways specifically BACE and TACE activities. Besides, although it has been showed that exercise can modulate secretase activities in Alzheimer Disease models the relationship between exercise effects and APP processing during healthy aging process is rarely studied. Our aim was to investigate the aging process and the exercise effects on cortical and hippocampal BACE and TACE activities and aversive memory performance. Young adult and aged Wistar rats were subjected to an exercise protocol (20min/day for 2 weeks) and to inhibitory avoidance task. Biochemical parameters were evaluated 1h and 18h after the last exercise session in order to verify transitory and delayed exercise effects. Aged rats exhibited impaired aversive memory and diminished cortical TACE activity. Moreover, an imbalance between TACE and BACE activities in favor of BACE activity was observed in aged brain. Moderate treadmill exercise was unable to alter secretase activities in any brain areas or time points evaluated. Our results suggest that aging-related aversive memory decline is partly linked to decreased cortical TACE activity. Additionally, an imbalance between secretase activities can be related to the higher vulnerability to neurodegenerative diseases induced by aging.

Fibronectin Modulates Cell Adhesion and Signaling to Promote Single Cell Migration of Highly Invasive Oral Squamous Cell Carcinoma.

Cell migration is regulated by adhesion to the extracellular matrix (ECM) through integrins and activation of small RhoGTPases, such as RhoA and Rac1, resulting in changes to actomyosin organization. During invasion, epithelial-derived tumor cells switch from laminin-enriched basal membrane to collagen and fibronectin-enriched connective tissue. How this switch affects the tumor migration is still unclear. We tested the hypothesis that ECM dictates the invasiveness of Oral Squamous Cell Carcinoma (OSCC). We analyzed the migratory properties of two OSCC lines, a low invasive cell line with high e-cadherin levels (Linv/HE-cad) or a highly invasive cell line with low e-cadherin levels (Hinv/LE-cad), plated on different ECM components. Compared to laminin, fibronectin induced non-directional collective migration and decreased RhoA activity in Linv/HE-cad OSCC. For Hinv/LE-cad OSCC, fibronectin increased Rac1 activity and induced smaller adhesions, resulting in a fast single cell migration in both 2D and 3D environments. Consistent with these observations, human OSCC biopsies exhibited similar changes in cell-ECM adhesion distribution at the invasive front of the tumor, where cells encounter fibronectin. Our results indicate that ECM composition might induce a switch from collective to single cell migration according to tumor invasiveness due to changes in cell-ECM adhesion and the resulting signaling pathways that alter actomyosin organization.

Radicular Cyst: An Update of the Biological Factors Related to Lining Epithelium.

INTRODUCTION: Radicular cysts are common lesions in daily dentistry practice. However, the mechanisms related to epithelial lining formation and cavity growth are not fully understood. Therefore, the purpose of this article was to review the biological factors implicated in these process. METHODS: Literature was selected through a search of PubMed electronic databases matching the following key words in the title or abstract: "cyst" OR "granuloma" OR "abscess" AND "radicular" OR "apical" OR "periapical" AND "epithelium" OR "epithelial" OR "epithelial lining." The PubMed database was searched for articles published between 1975 and 2014. Only English language was applied to the search. RESULTS: The literature search yielded a total of 187 articles. After duplicate references were discarded, a subsequent search at the title and abstract level revealed 42 articles for full-text reading. The articles were categorized into 5 main subtopics: (1) cell proliferation, cell cycle, and apoptosis; (2) extracellular matrix constituents; (3) inflammatory components; (4) bone metabolic factors and; (5) others. These subtopics described the characteristics of radicular cysts focusing on the epithelial tissue effects. CONCLUSIONS: Several factors from different sources (epithelial cells, stromal cells, extracellular matrix, and bone matrix) were implicated on apical cyst pathogenesis. Probably a combination of many factors involving an epithelial-stromal interaction is responsible for the sustenance and growth of apical cysts.

Cisplatin induces Bmi-1 and enhances the stem cell fraction in head and neck cancer.

Recent evidence has unveiled a subpopulation of highly tumorigenic, multipotent cells capable of self-renewal in head and neck squamous cell carcinomas (HNSCCs). These unique cells, named here cancer stem cells (CSCs), proliferate slowly and might be involved in resistance to conventional chemotherapy. We have shown that CSCs are found in perivascular niches and rely on endothelial cell-secreted factors [particularly interleukin-6 (IL-6)] for their survival and self-renewal in HNSCC. Here, we hypothesized that cisplatin enhances the stem cell fraction in HNSCC. To address this hypothesis, we generated xenograft HNSCC tumors with University of Michigan-squamous cell carcinoma 22B (UM-SCC-22B) cells and observed that cisplatin treatment increased (P = .0013) the fraction of CSCs [i.e., aldehyde dehydrogenase activity high and cluster of differentiation 44 high (ALDH(high)CD44(high))]. Cisplatin promoted self-renewal and survival of CSCs in vitro, as seen by an increase in the number of orospheres in ultralow attachment plates and induction in B lymphoma Mo-MLV insertion region 1 homolog (Bmi-1) and octamer-binding transcription factor 4 expression. Cisplatin-resistant cells expressed more Bmi-1 than cisplatin-sensitive cells. IL-6 potentiated cisplatin-induced orosphere formation generated when primary human HNSCC cells were sorted for ALDH(high)CD44(high) immediately after surgery and plated onto ultralow attachment plates. IL-6-induced signal transducer and activator of transcription 3 (STAT3) phosphorylation (indicative of stemness) was unaffected by treatment with cisplatin in UM-SCC-22B cells, whereas IL-6-induced extracellular signal-regulated kinase (ERK) phosphorylation (indicative of differentiation processes) was partially inhibited by cisplatin. Notably, cisplatin-induced Bmi-1 was inhibited by interleukin-6 receptor blockade in parental and cisplatin-resistant cells. Taken together, these results demonstrate that cisplatin enhances the fraction of CSCs and suggest a mechanism for resistance to cisplatin therapy in head and neck cancer.

Nanofiber scaffolds support bone regeneration associated with pulp stem cells.

Currently, there are a number of alternatives for bone grafting, though when used correctly they present physical, chemical or biological limitations, which justifies the pursuit for new alternatives for bone regeneration. This study gives a report on the potential for bone regeneration in the use of biodegradable nanofibers from poly (lactic-co-glycolic acid) (PLGA) in association with human mesenchymal stem cells from dental pulp of deciduous teeth (SCDT). Five samples of SCDT were seeded with scaffolds (test) or without scaffolds (control) for cell adhesion and viability assay. To evaluate the ability of the association in promoting bone formation, critical defects were made in the calvarium of rats (n=20), which were then divided into the following groups: I--sham group; II--implant of scaffolds; III--scaffolds/ SCDT; and IV--scaffolds/SCDT. They were kept for 13 days in osteogenic media. After 60 days, the histomorphometric analysis was performed. It was observed that the adherence and viability of SCDT in the control and test group were similar throughout the experiment (p>0.05). The association of scaffolds/SCDT maintained in osteogenic media, showed greater bone formation than the other groups (p<0.05). The study demonstrated that the association of SCDT seeded in biodegradable PLGA scaffolds has the ability to promote bone regeneration in rats, which is a promising alternative for application in regenerative medicine.

Characterization of tumorigenic cell lines from the recurrence and lymph node metastasis of a human salivary mucoepidermoid carcinoma.

UNLABELLED: The long-term outcome of patients with mucoepidermoid carcinoma is poor. Limited availability of cell lines and lack of xenograft models is considered a major barrier to improved mechanistic understanding of this disease and development of effective therapies. OBJECTIVE: To generate and characterize human mucoepidermoid carcinoma cell lines and xenograft models suitable for mechanistic and translational studies. METHODS: Five human mucoepidermoid carcinoma specimens were available for generation of cell lines. Cell line tumorigenic potential was assessed by transplantation and serial in vivo passaging in immunodeficient mice, and cell line authenticity verified by short tandem repeat (STR) profiling. RESULTS: A unique pair of mucoepidermoid carcinoma cell lines was established from a local recurrence (UM-HMC-3A) and from the metastatic lymph node (UM-HMC-3B) of the same patient, 4 years after surgical removal of the primary tumor. These cell lines retained epithelial-like morphology through 100 passages in vitro, contain the Crtc1-Maml2 fusion oncogene (characteristic of mucoepidermoid carcinomas), and express the prototypic target of this fusion (NR4A2). Both cell lines generated xenograft tumors when transplanted into immunodeficient mice. Notably, the xenografts exhibited histological features and Periodic Acid Schiff (PAS) staining patterns that closely resembled those found in human tumors. STR profiling confirmed the origin and authenticity of these cell lines. CONCLUSION: These data demonstrate the generation and characterization of a pair of tumorigenic salivary mucoepidermoid carcinoma cell lines representative of recurrence and lymph node metastasis. Such models are useful for mechanistic and translational studies that might contribute to the discovery of new therapies for mucoepidermoid carcinoma.

Estudo comparativo da morfologia da polpa dentária de dentes humanos submetidos à técnica de clivagem e a técnicas de descalcificação química / Comparative study of dental pulp morphology from human teeth submitted to cutting technique or chemistry decalcification technique

Os rápidos avanços do conhecimento acerca do reparo e regeneração tecidual, têm despertado o interesse pela biologia pulpar. Entretanto, para avaliar microscopicamente a dinâmica do tecido pulpar, é necessário, inicialmente, que o dente seja submetido aos processamentos histológicos de fixação e descalcificação. A descalcificação pode afetar o grau de coloração e pode causar desnaturação de proteínas. Além disso, é um processo demorado, visto que o dente requer um longo período de desmineralização. Assim, a proposta deste trabalho foi de avaliar qualitativamente a matriz extracelular e as células da polpa dentária, comparando três grupos: dois em que o tecido dentário foi descalcificado e um em que a polpa foi removida dos tecidos duros, não necessitando do processo de descalcificação. Dez pré-molares foram fixados em formalina tamponada a 10% por 24 horas. Após, estes dentes foram divididos em três grupos: 4 dentes foram submetidos a processo de descalcificação por meio de solução de Morse, 3 por meio de solução de EDTA a 10% e; os 3 dentes restantes tiveram sua polpa separada dos tecidos duros dentários por meio da técnica de clivagem. Na seqüência, os três grupos foram processados por meio da técnica histológica de rotina e foram corados com H/E. Os resultados desta análise demonstraram que houve uma melhor conservação tanto da matriz extracelular, quanto das estruturas celulares no grupo da clivagem, seguido do grupo Morse e por fim, com a menor conservação das estruturas pelo grupo EDTA.

The rapid advances of the knowledge of repair and regeneration tissues had proved to be an exciting time for pulp biology. However, to study the dynamic of pulp tissue, it is necessary, initially, that the tooth be submitted to histological fixation and decalcification processing. Decalcification may affect the degree of staining and it may cause denaturation of proteins. Furthermore, it is a slow process, demanding long demineralization times for a tooth. Thus, the purpose of the present study was to compare, qualitatively, the pulp extracellular matrix and the pulp cells, submitted to different techniques: EDTA solution decalcification, Anna Morse solution decalcification and a last group which pulp was removed from tooth without decalcification. Ten premolar teeth were fixed in 10% buffered formalin for 24 hours. After this, the teeth were divided in three groups: 4 teeth underwent decalcification with Morse solution; 3, decalcification with 10% EDTA solution and; 3, were sectioned and their pulps were gently removed. Subsequently, the groups followed the routine histological technique and staining with H/E. The results demonstrated that both conservation of pulp cells and extracellular matrix were better in the group without decalcification, followed by the Morse group and, the last, with the worst structures conservation for the EDTA group.