Noma: A Neglected Area for Research

Noma, a debilitating and destructive orofacial gangrene, remains endemic in the poor countries of sub-Saharan Africa and other noma hotbeds across the globe, mainly in countries characterized as underdeveloped economies with significant impoverished populations. Noma mostly affects children and infants. This is in spite of the universally held notion that noma is a preventable disease. Indeed, the current noma status quo has been cast as a human rights shortfall, since this devasting disease overwhelmingly affects children from poor countries. At the recently held Noma Research Day, a renewed call for the World Health Organization (WHO) to recognize and include noma as one of the neglected tropical diseases was accompanied by a recognition that research into all aspects of noma has waned or remained completely lacking-particularly that which addresses the basic science questions of the etiology, pathophysiology/pathobiology, and underlying mechanisms of the disease. Yet, a lack of incremental knowledge on the various aspects of noma continues to hamper our composite understanding of its biology. Without a fundamental understanding of the biology of noma, current preventive measures and treatment modalities will continue to fall short of the goals of prevention and eradication. This opinion piece draws renewed attention to the urgency of listing noma as a neglected tropical disease by the WHO. It also calls for major international research funding agencies, including the WHO and the National Institutes of Health, to renew their resolve to robustly fund structured, collaborative, and coordinated proposals that address questions on the epidemiology, etiology, pathophysiology/pathobiology, and molecular mechanisms of the disease. This is with a view to achieving more effective public health approaches toward prevention and to designing potential therapeutic regimens for early lesions. These steps are key to the ultimate eradication of noma.

Metastatic renal cell carcinoma to the oral cavity as first sign of disease: A case report

Renal cell carcinoma metastasis to the oral cavity is rare. Significantly, the oral lesion in this case was the first indication of a malignant disease in the patient. This case underscores the importance of detailed history taking, interpretation of clinical finding, and high index of suspicion for metastatic disease to the oral cavity.

Development and Validation of a Combined Hypoxia and Immune Prognostic Classifier for Head and Neck Cancer

PURPOSE

Intratumoral hypoxia and immunity have been correlated with patient outcome in various tumor settings. However, these factors are not currently considered for treatment selection in head and neck cancer (HNC) due to lack of validated biomarkers. Here we sought to develop a hypoxia-immune classifier with potential application in patient prognostication and prediction of response to targeted therapy.

EXPERIMENTAL DESIGN

A 54-gene hypoxia-immune signature was constructed on the basis of literature review. Gene expression was analyzed in silico using the The Cancer Genome Atlas (TCGA) HNC dataset (n = 275) and validated using two independent cohorts (n = 130 and 123). IHC was used to investigate the utility of a simplified protein signature. The spatial distribution of hypoxia and immune markers was examined using multiplex immunofluorescence staining.

RESULTS

Unsupervised hierarchical clustering of TCGA dataset (development cohort) identified three patient subgroups with distinct hypoxia-immune phenotypes and survival profiles: hypoxialow/immunehigh, hypoxiahigh/immunelow, and mixed, with 5-year overall survival (OS) rates of 71%, 51%, and 49%, respectively (P = 0.0015). The prognostic relevance of the hypoxia-immune gene signature was replicated in two independent validation cohorts. Only PD-L1 and intratumoral CD3 protein expression were associated with improved OS on multivariate analysis. Hypoxialow/immunehigh and hypoxiahigh/immunelow tumors were overrepresented in "inflamed" and "immune-desert" microenvironmental profiles, respectively. Multiplex staining demonstrated an inverse correlation between CA-IX expression and prevalence of intratumoral CD3+ T cells (r = -0.5464; P = 0.0377), further corroborating the transcription-based classification.

CONCLUSIONS

We developed and validated a hypoxia-immune prognostic transcriptional classifier, which may have clinical application to guide the use of hypoxia modification and targeted immunotherapies for the treatment of HNC.

Survey of dentin sialophosphoprotein and its cognate matrix metalloproteinase-20 in human cancers

Background

Matrix metalloproteinases‐20 (MMP20) expression is widely regarded as tooth specific, with expression limited to dental hard tissues. Recently, we reported MMP20 expression and interaction with dentin sialophosphoprotein (DSPP), a member of the Small Integrin Binding Ligand N‐linked Glycoproteins (SIBLINGs), in human oral squamous cell carcinoma (OSCC) and dysplastic oral premalignant lesions (OPLs), suggesting a role for MMP20‐DSPP interaction in oral carcinogenesis.

Methods

This study aimed to survey the expression of MMP20 and its cognate DSPP partner in the breast, colon, prostate, thyroid, and cervical neoplasms. Using commercially available tissue microarrays (TMAs) and cell lines, we performed immunohistochemistry, immunofluorescence, proximity ligation assay, and western blot experiments to determine the expressions of MMP20 and DSPP in the breast, colon, prostate, thyroid, cervical neoplasms, and their normal counterparts.

Results

Significantly high expression levels of MMP20 and DSPP were observed in the malignant breast, colon, prostate, thyroid, and cervical neoplasms compared with their benign and normal counterparts. Furthermore, MMP20 levels increased with advanced stages of colon and thyroid cancers. DSPP expression increased significantly with tumor stage in all cancers examined.

Conclusions

The co‐localization and potential MMP20‐DSPP interaction previously reported in oral cancers are present in other cancers. These results suggest MMP20‐DSPP pairing as a potential marker of disease activity in some epithelial cancers with diagnostic and prognostic implications.

Interferon γ suppresses dentin sialophosphoprotein in oral squamous cell carcinoma cells resulting in antitumor effects, via modulation of the endoplasmic reticulum response

The expression of proinflammatory cytokines in various malignant neoplasms is widely considered to represent the host immune response to tumor development. The role of interferon (IFN)γ in head and neck squamous cell carcinoma, and its association with endoplasmic reticulum (ER) stress pathways, remains a subject of ongoing investigation. Dentin sialophosphoprotein (DSPP), which is a member of the small integrin-binding N-linked glycoproteins family, has been implicated in malignant transformation and invasion of oral squamous cell carcinoma (OSCC). Recent studies have established matrix metalloproteinase (MMP)20 as the cognate MMP partner of DSPP. The present study examined the effects of IFNγ treatment on DSPP and MMP20 expression, ER stress, the unfolded protein response (UPR), and calcium (Ca) homeostasis regulatory mechanisms in OSCC cells. The OSC2 OSCC cell line was treated with IFNγ at specific time-points. At each time-point, the mRNA expression levels of DSPP and MMP20, and those of ER-stress-, UPR- and Ca homeostasis-associated proteins [78-kDa glucose-regulated protein (GRP78), sarco/endoplasmic reticulum Ca²⁺-ATPase (SERCA2b), inositol 1,4,5-trisphosphate receptor (IP3r), protein kinase R-like ER kinase (PERK) and inositol-requiring enzyme 1 (IRE1)], were assessed by reverse transcription-quantitative polymerase chain reaction. The protein expression levels of B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax), proliferating cell nuclear antigen (PCNA) and cytochrome c were analyzed by western blotting. Cell viability, apoptosis and migration were evaluated by MTT, Annexin V-fluorescein isothiocyanate flow cytometry and wound-healing assays, respectively. IFNγ treatment significantly downregulated the mRNA expression levels of the major ER stress regulator GRP78 and, to a lesser extent, the UPR-associated molecule IRE1; however, IFNγ had no significant effect on PERK. With regards to ER Ca homeostasis molecules, treatment with IFNγ downregulated the mRNA expression levels of SERCA2b and upregulated those of IP3r. Furthermore, DSPP and MMP20 mRNA expression levels were significantly reduced following IFNγ treatment. Notably, treatment with IFNγ hampered OSC2 migration, reduced cell viability and PCNA protein expression, enhanced apoptosis, downregulated Bcl-2, and upregulated Bax and cytochrome c. Overall, IFNγ inhibited OSCC cell viability and migration, and increased apoptosis, possibly by regulating ER stress and UPR mechanisms. In addition, IFNγ-induced DSPP and MMP20 downregulation may correspond with alteration in ER Ca homeostasis.

The tumorigenic role of DSPP and its potential regulation of the unfolded protein response and ER stress in oral cancer cells

Dentin sialophosphoprotein (DSPP) is upregulated in various human cancers, including head and neck squamous cell carcinoma. Cancer cells are commonly found under constant endoplasmic reticulum (ER) stress and exhibit increased levels of misfolded proteins, due to gene mutations and a stressful microenvironment. The present study examined the effects of DSPP silencing on the regulation of ER stress and the unfolded protein response (UPR) in oral cancer cells. A recently established stable DSPP short hairpin (sh)RNA-silenced OSC2 oral cancer cell line was used. The mRNA expression levels of ER stress-associated proteins, including 78 kDa glucose-regulated protein (GRP78), sarcoplasmic/endoplasmic reticulum calcium ATPase 2b (SERCA2b), inositol 1,4,5-trisphosphate receptor (IP3r), protein kinase R-like endoplasmic reticulum kinase (PERK), serine/threonine-protein kinase/endoribonuclease IRE1 (IRE1), activating transcription factor 6 (ATF6) and matrix metalloproteinase 20 (MMP20), were assessed by reverse transcription-quantitative polymerase chain reaction. The expression levels of apoptosis-related [B‑cell lymphoma 2 (Bcl2), Bcl2-associated X protein (Bax) and cytochrome c] and cell proliferation-related [proliferating cell nuclear antigen (PCNA)] proteins were analyzed by western blotting. Cell viability, apoptosis and migration were monitored by MTT assay, Annexin V-fluorescein isothiocyanate flow cytometry and wound-healing assay, respectively. In transiently transfected puromycin‑free OSC2 cells, DSPP silencing markedly downregulated the mRNA expression levels of major ER stress regulators, including GRP78, SERCA2b, PERK, IRE1 and ATF6, as well as MMP20. DSPP silencing also resulted in decreased cell viability and migration, and enhanced apoptosis. Furthermore, PCNA and Bcl2 levels were decreased, whereas Bax and cytochrome c protein levels were increased in DSPP-silenced OSC2 cells. Sustained puromycin treatment partially counteracted the effects of DSPP silencing on the mRNA expression levels of ER stress-related proteins and MMP20, and on the migratory capacity of OSC2 cells. However, following puromycin treatment of DSPP-silenced cells, cell viability was further reduced and apoptosis was enhanced. In conclusion, these data provide evidence to suggest that DSPP may be involved in ER stress mechanisms in oral squamous cell carcinoma, since its downregulation in OSC2 cells led to significant alterations in the levels of major ER stress-associated proteins, and subsequent collapse of the UPR system.

DSPP-MMP20 gene silencing downregulates cancer stem cell markers in human oral cancer cells

BACKGROUND

Recent findings indicate that dentin sialophosphoprotein (DSPP) and matrix metalloproteinase (MMP) 20 interact in oral squamous cell carcinoma (OSCC). The objective of this study was to determine the effects of DSPP/MMP20 gene silencing on oral cancer stem cell (OCSC) markers.

METHODS

The expression of well-established OCSC markers: ABCG2; ALDH1; CD133; CD44; BMI1; LGR4, and Podoplanin in DSPP/MMP20-silenced OSCC cell line, OSC2, and controls were assayed by western blot (WB), and flow cytometry techniques. The sensitivity of OSC2 cells to cisplatin following DSPP/MMP20 silencing was also determined.

RESULTS

DSPP/MMP20 silencing resulted in downregulation of OCSC markers, more profoundly ABCG2 (84%) and CD44 (81%), following double silencing. Furthermore, while treatment of parent (pre-silenced) OSC2 cells with cisplatin resulted in upregulation of OCSC markers, DSPP/MMP20-silenced OSC2 cells similarly treated resulted in profound downregulation of OCSC markers (72 to 94% at 50 μM of cisplatin), and a marked reduction in the proportion of ABCG2 and ALDH1 positive cells (~ 1%).

CONCLUSIONS

We conclude that the downregulation of OCSC markers may signal a reduction in OCSC population following MMP20/DSPP silencing in OSCC cells, while also increasing their sensitivity to cisplatin. Thus, our findings suggest a potential role for DSPP and MMP20 in sustaining OCSC population in OSCCs, possibly, through mechanism(s) that alter OCSC sensitivity to treatment with chemotherapeutic agents such as cisplatin.

Emerging paradigm of virtual-microscopy for histopathology diagnosis: survey of US and Canadian oral pathology trainees

Objectives/Aims:

The application of virtual microscopy (VM) to research, pre-doctoral medical and dental educational training, and diagnostic surgical and anatomic pathology is well-documented but its application to the field of oral and maxillofacial pathology has not been explored. This is the first study to evaluate the enthusiasm and readiness of US-/Canada-based oral and maxillofacial pathology (OMFP) residents toward employing VM use over conventional microscopy (CM) for diagnostic purposes.

Materials and Methods:

All 46 current US-/Canada-based OMFP residents were invited to participate in an anonymous electronic survey via ‘Survey Monkey’ in 2015. The survey comprised sixteen multiple choice questions and two ‘free text’ questions.

Results:

14% of respondents of the 22 (48%) respondents who completed the survey indicated a willingness to substitute CM with VM in <5 years, and 33% within 10 years. 52% reported they would never substitute CM with VM. Approximately 10 and 57% of respondents thought VM will become an acceptable sole diagnostic tool in most centers within 5 and 10 years, respectively. These findings are irrespective of the fact that overall, 90% of respondents reported being familiar with VM use.

Discussion:

VM technology is unlikely to substitute CM in diagnostic oral and maxillofacial histopathology practice among future OMFP practitioners in the foreseeable future.

Expression of the SIBLINGs and their MMP partners in human benign and malignant prostate neoplasms

The small integrin binding ligands n-linked glycoproteins (SIBLINGs) have emerged as potential diagnostic and prognostic indices, and as key targets, in cancer therapy. Three members of the SIBLING family: bone sialoprotein (BSP); osteopontin (OPN); and dentin matrix protein1 (DMP1), bind and interact with specific matrix metalloproteinases (MMPs): BSP-MMP2; OPN-MMP3; DMP1-MMP9, in biochemical and biologic systems. The other two family members are dentin sialophosphoprotein (DSPP) and matrix extracellular phosphoglycoprotein (MEPE). The specific SIBLING-MMP pairing reported in some cancers have not been reported in prostate neoplasms. In this study, we investigated SIBLING-MMP expression and potential interaction in prostate neoplasms. Chi square analysis of immunohistochemistry results showed significant upregulation of OPN (X2=25.710/p<0.001), BSP (X2=19.546/p<0.001), and DSPP (X2=8.720/p=0.003) in prostate adenocarcinoma (pAdC). MEPE was significantly upregulated in benign prostate hyperplasia (BPH; X2=44.153/p<0.001). There were no significant differences in MMP expression between BPH and pAdC. Western blot analysis showed significantly elevated BSP and DSPP in prostate cancer-derived cells. Immunofluorescence studies confirmed BSP-MMP2, OPN-MMP3, and DMP1-MMP9 coexpression in two cancer-derived cell lines, whereas in situ proximity ligation assays confirmed potential BSP-MMP2, OPN-MMP3, and DMP1-MMP9 interactions in BPH and pAdC. Our reports provide evidence that SIBLING-MMP interaction may play a role in the progression of BPH to pAdC.

Matrix Metalloproteinase 20 Co-expression With Dentin Sialophosphoprotein in Human and Monkey Kidneys

We recently reported the expression of matrix metalloproteinase 20 (MMP20), hitherto thought to be tooth specific, in the metabolically active ductal epithelial cells of human salivary glands. Furthermore, our report indicated that MMP20 co-expressed and potentially interacts with dentin sialophosphoprotein (DSPP), a member of the small integrin-binding ligand N-linked glycoproteins (SIBLINGs). Our earlier reports have shown the co-expression of three MMPs, MMP2, MMP3, and MMP9, with specific members of the SIBLING family: bone sialoprotein, osteopontin, and dentin matrix protein 1, respectively. This study investigated the expression of MMP20 and verified its co-expression with DSPP in human and monkey kidney sections and human mixed renal cells by IHC, in situ proximity ligation assay, and immunofluorescence. Our results show that MMP20 is expressed in all segments of the human and monkey nephron with marked intensity in the proximal and distal tubules, and was absent in the glomeruli. Furthermore, MMP20 co-expressed with DSPP in the proximal, distal, and collecting tubules, and in mixed renal cells. Consistent with other SIBLING-MMP pairs, the DSPP-MMP20 pair may play a role in the normal turnover of cell surface proteins and/or repair of pericellular matrix proteins of the basement membranes in the metabolically active duct epithelial system of the nephrons.

Expression of Matrix Metalloproteinase (MMP)-20 and Potential Interaction with Dentin Sialophosphoprotein (DSPP) in Human Major Salivary Glands

Matrix metalloproteinase-20 (MMP-20) expression is widely regarded as tooth-specific, with expression limited to dental hard tissues. Necessary for sound enamel formation, MMP-20 and MMP-2 proteolytically process dentin sialophosphoprotein (DSPP) into dentin sialoprotein, dentin phosphoprotein, and dentin glycoprotein during tooth formation. In the mid-2000s, three members of the small integrin-binding ligand N-linked glycoproteins (SIBLINGs) were reported to bind specifically with high affinity (nM) to, and activate, three MMPs in vitro: bone sialoprotein with MMP-2; osteopontin with MMP-3; and dentin matrix protein1 with MMP-9. The SIBLING-MMP interaction was confirmed in biological systems such as the ducts of salivary glands, where all five members of the SIBLINGs are expressed. Recently, we documented MMP-20 expression and interaction with DSPP (another member of the SIBLING family) in human oral squamous cell carcinoma. Here we report the expression of MMP-20, and confirm its co-expression and potential interaction with DSPP in human major salivary gland tissues and cell line using immunohistochemistry, immunofluorescence, western blot, quantitative RT-PCR, and proximity ligation assay. This report reinforces our earlier suggestion that the SIBLING-MMP complexes may be involved in the turnover of extracellular proteins damaged by oxidation byproducts in metabolically active duct epithelial systems.

A peripheral giant cell granuloma with extensive osseous metaplasia or a hybrid peripheral giant cell granuloma-peripheral ossifying fibroma: a case report

INTRODUCTION

Peripheral giant cell granuloma and peripheral ossifying fibroma are clinicopathologically distinct gingival lesions. Both are included in clinical differential diagnoses of common benign and reactive gingival epulides in humans. It is often impossible to make a clinical distinction between the two entities, thereby making definitive diagnosis dependent on histopathologic features. While our search of the English literature revealed several reports of peripheral giant cell granuloma with 'bone formation', we were unable to identify any reports of hybrid peripheral ossifying fibroma-peripheral giant cell granulomas.

CASE PRESENTATION

We report a case of a 44-year-old Caucasian man presenting with a three-month history of swelling of his right posterior mandible, related to an area of previous dental implant restoration. A clinical examination revealed modest extraoral facial swelling of his right posterior mandible, while an intraoral examination showed a 45 × 25 × 15 mm sessile, lobular soft tissue mass of the right posterior mandibular gingiva. The mucosal covering of the lesion exhibited focal surface ulceration. A panoramic radiograph showed two implants at the vicinity of the lesion with no other significant findings. An excisional biopsy of the lesion followed by histopathologic examination of the biopsy specimen revealed salient and distinctive features of peripheral giant cell granuloma and of peripheral ossifying fibroma, estimated at near equal proportions. This raises the possibility of a hybrid odontogenic lesion.

CONCLUSION

The presentation of this lesion, with areas of peripheral giant cell granuloma along with a distinct area of extensive osseous formation and stroma reminiscent of a peripheral ossifying fibroma, justifies consideration of this as a possible hybrid lesion. Although the biologic behavior of a combined lesion is not anticipated to deviate significantly from that of either of the single entities, this case resurrects an enduring debate as to whether peripheral giant cell granuloma and peripheral ossifying fibroma are simply parts of a disease spectrum, or whether some of these lesions represent true hybrid lesions. It is therefore recommended that more cases with histopathologic features similar to the lesion in our case be reported in the literature to further elucidate the histogenesis of these lesions.

Blue light activates phase 2 response proteins and slows growth of a431 epidermoid carcinoma xenografts

BACKGROUND

Recent studies suggest that light in the UVA range (320-400 nm) activates signaling pathways that are anti-inflammatory, antioxidative and play a critical role in protection against cancer. These effects have been attributed to NF-E2-related factor (NRF2)-mediated up-regulation of 'phase 2' genes that neutralize oxidative stress and metabolize electrophiles. We had previously shown that small doses of blue light (400-500 nm) had selective toxicity for cultured oral tumor cells and increased levels of peroxiredoxin phase 2 proteins, which led to our hypothesis that blue light activates NRF2 signaling.

MATERIALS AND METHODS

A431 epidermoid carcinoma cells were treated in culture and as nude mouse xenografts with doses of blue light. Cell lysates and tumor samples were tested for NRF2 activation, and for markers of proliferation and oxidative stress.

RESULTS

Blue light activated the phase 2 response in cultured A431 cells and reduced their viability dose dependently. Light treatment of tumors reduced tumor growth, and levels of proliferating cell nuclear antigen (PCNA), and oxidized proteins.

DISCUSSION

Cellular responses to these light energies are worth further study and may provide therapeutic interventions for inflammation and cancer.

Expression of p8 in Human Oral Squamous Cell Carcinoma

The present study investigated the expression of p8, a transcription factor upregulated in some human cancers, in oral squamous cell carcinomas (OSCCs). Immunohistochemical analysis of p8 expression was carried out on 20 archived surgical specimens of human OSCCs, and expression correlated with clinical outcome parameters in a retrospective study. Expression of p8 in a number of OSCC cell lines also was investigated by western blot and RT-PCR analyses. p8 was expressed in 80 % (16/20) of the samples with levels of expression exhibiting a significant difference (χ(2) = 8.352, df = 3, p = 0.039) by patient age. Furthermore, greater levels of p8 immunoreactivity was significantly associated with advanced tumor grade (p = 0.008). p8 also was upregulated in OSCC cell lines. p8 is expressed in a significant proportion of OSCCs, and in human OSCC cell lines, suggesting a potential value of p8 as a diagnostic and/prognostic tool for oral cancers.

Expressions of matrix metalloproteinase-9 (MMP-9), dentin sialophosphoprotein (DSPP), and osteopontin (OPN) at histologically negative surgical margins may predict recurrence of oral squamous cell carcinoma

Up to 50% of oral squamous cell carcinomas (OSCCs) recur following surgical resections with conventional “histologically-negative” margins. Three members of the SIBLING (Small Integrin Binding LIgand N-linked Gylcoprotein) family of proteins: dentin sialophophoprotein (DSPP); bone sialoprotein (BSP); and osteopontin OPN are upregulated in OSCCs. In this study, we aimed to correlate the expression of DSPP, OPN and BSP as well as three SIBLING-partners, matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-3 (MMP-3), and matrix metalloproteinase-9 (MMP-9), at histologically-negative margins of OSCCs with tumor recurrence. Immunohistochemical analyses of the SIBLINGs and MMP expressions at histologically-negative margins of OSCC was carried out in a retrospective study of 20 patients, and the results correlated with tumor recurrence. Each protein was dichotomized as “present” (≥10% staining) or “absent” (< 10% staining). The Sensitivity, Specificity, Positive Predictive Value(PV+) and Negative Predictive Value (PV−) for recurrence was calculated for each protein, along with their overall diagnostic accuracy, calculated as: (number of true positives + number of true negatives)/ number of patients. OSCC recurred in 9 of 20 patients (45%), a ratio not significantly different from the estimated population recurrence rate of 50% (p = 0.664). Among the SIBLINGs, DSPP and OPN showed the greatest Accuracy with DSPP being more Sensitive (89%) and OPN more Specific (64%). MMP-9 showed the greatest overall Accuracy (80%), slightly less Sensitivity (67%) and more Specificity (100%), than either DSPP or OPN. MMP-9 showed a superior positive PV than either DSPP or OPN. The negative PVs of OPN and MMP-9 were almost identical, and inferior to DSPP. We conclude that DSPP, OPN, or MMP-9 expressions at histologically-negative surgical margins predict OSCC recurrence with MMP-9 being the preferred predictor. These proteins may identify patients who could benefit from more extensive resection, or from adjunct treatments such as radiotherapy.

Dentin sialophosphoprotein (DSPP) gene-silencing inhibits key tumorigenic activities in human oral cancer cell line, OSC2

Background

We determined recently that dentin sialophosphoprotein (DSPP), a member of the SIBLING (Small integrin-binding ligand N-linked glycoproteins) family of phosphoglycoproteins, is highly upregulated in human oral squamous cell carcinomas (OSCCs) where upregulation is associated with tumor aggressiveness. To investigate the effects of DSPP-silencing on the tumorigenic profiles of the oral cancer cell line, OSC2, short-hairpin RNA (shRNA) interference was employed to silence DSPP in OSC2 cells.

Methodology/Principal Findings

Multiple regions of DSPP transcript were targeted for shRNA interference using hDSP-shRNA lentiviral particles designed to silence DSPP gene expression. Control shRNA plasmid encoding a scrambled sequence incapable of degrading any known cellular mRNA was used for negative control. Following puromycin selection of stable lines of DSSP-silenced OSC2 cells, phenotypic hallmarks of oral carcinogenesis were assayed by western blot and RT-PCR analyses, MTT (cell-viability), colony-formation, modified Boyden-Chamber (migration and invasion), and flow cytometry (cell-cycle and apoptosis) analyses. DSPP-silenced OSC2 cells showed altered cell morphology, reduced viability, decreased colony-formation ability, decreased migration and invasion, G0/G1 cell-cycle arrest, and increased tumor cell sensitivity to cisplatin-induced apoptosis. Furthermore, MMP-2, MMP-3, MMP-9, VEGF, Ki-67, p53, and EGFR were down-regulated. There was a direct correlation between the degree of DSPP-silencing and MMP suppression, as indicated by least squares regression: MMP-2 {(y = 0.850x, p<0.001) (y = 1.156x, p<0.001)}, MMP-3 {(y = 0.994x, p<0.001) (y = 1.324x, p = 0.004)}, and MMP-9 {(y = 1.248x, p = 0.005, y = 0.809, p = 0.013)}.

Conclusions/Significance

DSPP-silencing in OSC2 cell decreased salient hallmarks of oral tumorigenesis and provides the first functional evidence of a potential key role for DSPP in oral cancer biology. The down-regulation of MMP-2, MMP-3, MMP-9, p53 and VEGF in DSPP-silenced OSC2 cells provides a significant functional/molecular framework for deciphering the mechanisms of DSPP activities in oral cancer biology.

Two members of the SIBLING family of proteins, DSPP and BSP, may predict the transition of oral epithelial dysplasia to oral squamous cell carcinoma

BACKGROUND

: Patients with oral premalignant lesions (OPL) present with oral squamous cell carcinomas (OSCC) at a much higher rate than the general population. There are currently no useful markers that indicate specifically which OPLs are most likely to progress. Three small integrin binding ligands N-linked glycoprotein (SIBLING) family proteins, bone sialoprotein (BSP), osteopontin (OPN), and dentin sialophosphoprotein (DSPP), have been shown to be up-regulated in many cancers, including OSCC. The status of SIBLING expression in OPLs and their correlation to transition to oral cancer are unknown.

METHODS

: Sixty archival surgical biopsies of dysplastic OPLs were evaluated by immunohistochemistry for expression of BSP, DSPP, and OPN and correlated with local transformation to OSCC at sites adjacent to surgically removed dysplastic OPL.

RESULTS

: The OPL patient population was representative of previous studies with 20% progressing to OSCC, and no correlation between degree of dysplasia and progression. Eighty-seven percent were positive for at least 1 SIBLING protein. OPN expression had no correlation with progression. The BSP+/DSPP- expression pattern however correlated with decreased transformation to OSCC (point prevalence = 0%; 95% confidence interval [CI], 0-20.6), whereas the BSP-/DSPP+ pattern was associated with more frequent progression (point prevalence = 77.8%; 95%CI, 47.8-95.4). Incrementally higher expression scores (0 to 3) of BSP and DSPP were also associated with increased predictive values (odds ratio, 25.53; 95% CI, 2.14-304.7 and 10.13; 95% CI, 2.0-50.0, respectively, for each increment).

CONCLUSIONS

: BSP and DSPP are excellent candidate markers for successful OPL surgical intervention and may be predictors of OPL-OSCC progression. Cancer 2010. (c) 2010 American Cancer Society.

Exogenous expression of caspase-14 induces tumor suppression in human salivary cancer cells by inhibiting tumor vascularization

BACKGROUND

Current therapeutic approaches to salivary gland cancer are often associated with severe disfigurement and loss of glandular function, which are traumatic to the patients. Exploration of novel treatment approaches, such as gene therapy, is needed.

MATERIALS AND METHODS

The human salivary gland cancer cell line HSG was transiently transfected with full length human caspase-14 cDNA. Photomicroscopy, BrdU assay, cell counting, MTT assay, and TUNEL assay were applied. To determine the tumorigenicity, tumor volume, tumor pathology and vascularization were analyzed in vivo.

RESULTS

Cell growth and viability were inhibited significantly by transient caspase-14 expression. Caspase-14 expression resulted in a significant reduction of tumorigenicity. Importantly, a significant decrease in tumor blood vessel formation was observed.

CONCLUSION

Salivary gland cancer cells underwent growth inhibition, cell death, and reduced tumorigenicity in vivo when exogenous caspase-14 was expressed, which could be due, in part, to an inhibitory effect of caspase-14 on tumor vascularization.

Effects of oral consumption of the green tea polyphenol EGCG in a murine model for human Sjogren's syndrome, an autoimmune disease

SIGNIFICANCE

Protection of glandular cells from autoimmune-induced damage would be of significant clinical benefit to Sjogren's syndrome (SS) patients. Epigallocatechin-3-gallate (EGCG) possesses anti-apoptotic, anti-inflammatory, and autoantigen-inhibitory properties.

AIMS

To investigate if EGCG protects against certain autoimmune-induced pathological changes in the salivary glands of the non-obese diabetic (NOD) mouse model for SS.

MAIN METHODS

Animals were provided with either water or water containing 0.2% EGCG. At the age of 8, 16 and 22 weeks, submandibular salivary gland tissue and serum samples were collected for pathological and serological analysis.

KEY FINDINGS

Significant lymphocyte infiltration was observed in the salivary glands of the water-fed group at the age of 16 weeks, while the EGCG group showed reduced lymphocyte infiltration. By 22 weeks of age, water-fed animals demonstrated elevated levels of apoptotic activity within the lymphocytic infiltrates, and high levels of serum total anti-nuclear antibody, compared to EGCG-fed animals. Remarkably, proliferating cell nuclear antigen (PCNA) and Ki-67 levels in the salivary glands of water-fed NOD mice were significantly elevated in comparison to BALB/c control mice; in contrast, PCNA and Ki-67 levels in EGCG-fed NOD animals were similar to BALB/c mice. These results indicate that EGCG protects the NOD mouse submandibular glands from autoimmune-induced inflammation, and reduces serum autoantibody levels. Abnormal proliferation, rather than apoptosis, appears to be a characteristic of the NOD mouse gland that is normalized by EGCG. The evidence suggests that EGCG could be useful in delaying or managing SS-like autoimmune disorders.

Small integrin-binding ligand N-linked glycoproteins (SIBLINGs): multifunctional proteins in cancer

Numerous components and pathways are involved in the complex interplay between cancer cells and their environment. The family of glycophosphoproteins comprising osteopontin, bone sialoprotein, dentin matrix protein 1, dentin sialophosphoprotein and matrix extracellular phosphoglycoprotein - small integrin-binding ligand N-linked glycoproteins (SIBLINGs) - are emerging as important players in many stages of cancer progression. From their detection in various human cancers to the demonstration of their key functional roles during malignant transformation, invasion and metastasis, the SIBLINGs are proteins with potential as diagnostic and prognostic tools, as well as new therapeutic targets.

Green tea polyphenols reduce autoimmune symptoms in a murine model for human Sjogren's syndrome and protect human salivary acinar cells from TNF-alpha-induced cytotoxicity

Sjogren's syndrome (SS) is a relatively common autoimmune disorder. A key feature of SS is lymphocytic infiltration of the salivary and lacrimal glands, associated with the destruction of secretory functions of these glands. Current treatment of SS targets the symptoms but is unable to reduce or prevent the damage to the glands. We reported previously that the major green tea polyphenol (GTP) epigallocatechin-3-gallate (EGCG) inhibits autoantigen expression in normal human keratinocytes and immortalized normal human salivary acinar cells (Hsu et al. 2005). However, it is not known whether GTPs have this effect in vivo, if they can reduce lymphocytic infiltration, or protect salivary acinar cells from tumor necrosis factor-alpha (TNF-alpha)-induced cytotoxicity. Here, we demonstrate that in the NOD mouse, a model for human SS, oral administration of green tea extract reduced the serum total autoantibody levels and the autoimmune-induced lymphocytic infiltration of the submandibular glands. Further, we show that EGCG protected normal human salivary acinar cells from TNF-alpha-induced cytotoxicity. This protection was associated with specific phosphorylation of p38 MAPK, and inhibitors of the p38 MAPK pathway blocked the protective effect. In conclusion, GTPs may provide a degree of protection against autoimmune-induced tissue damage in SS, mediated in part through activation of MAPK elements.

Huge peripheral osteoma of the mandible: a case report and review of the literature

Osteomas are rare benign tumors of bone commonly occurring in the maxillofacial skeleton. In the course of their slow but steady increase in size, osteomas of the maxillofacial bones remain asymptomatic until they attain sufficient sizes as to cause disfigurement and/or direct interference with the normal function of their anatomic location. Here, we report a case of a huge solitary peripheral osteoma of the lingual posterior mandible in a 50-year-old woman who was otherwise in good health. The patient reported at the dental clinic because the lesion interfered with speech, swallowing, and caused occasional gagging. Histological examination confirmed the clinical impression of a peripheral osteoma. Treatment was by surgical excision and histological examination. The patient remains free of recurrence after 5 years.

Up-regulation of SIBLING proteins and correlation with cognate MMP expression in oral cancer

Various combinations of the SIBLING family of proteins have been found to be up-regulated in many human cancers and have been linked to different stages of tumor progression, including metastasis. Bone sialoprotein (BSP), osteopontin (OPN) and dentin matrix protein 1 (DMP1) specifically bind and activate MMP-2, MMP-3, and MMP-9, respectively. These proteases have also been shown to play important roles in oral squamous cell carcinoma (OSCC) invasion and metastasis. However, with the exception of OPN, there are no reports on the expression of the family of five SIBLING proteins in OSCC. This study examines the expression patterns of the SIBLING family (and MMP partners when known) in OSCC, correlating expression to outcome variables. Archived paraffin sections of 87 cases of primary OSCC were screened by immunohistochemistry for the SIBLINGs and their MMP partners. Three SIBLINGs (BSP, DSPP, and OPN), were expressed in OSCC, while DMP1 and MEPE expression were never observed. Furthermore, BSP and OPN were always expressed with their known MMP partners, MMP-2 and MMP-3, respectively. Poorly differentiated tumors exhibited reduced or no immunoreactivity for BSP and OPN but increased immunoreactivity for DSPP. Seventy eight (90%) cases were positive for BSP and DSPP, while 79 cases (91%) were positive for OPN. Overall, 91% of the cases were positive for at least one SIBLING. There were no correlations between SIBLING expression and tumor size ("T"; of the Union Internationale Contre le Cancer [UICC]-TNM classification for OSCC), and between SIBLING expression and lymph node spread for the T1/T2 tumors. The levels of DSPP expression for floor of mouth and retromolar region tumors were higher than for tongue tumors. Statistically significant correlations were, however, found between the expression levels of BSP and MMP-2 (p<0.0001), BSP and MMP-3 (p<0.0001), and OPN and MMP-3 (p<0.0024). We conclude that BSP, DSPP, and OPN are highly up-regulated in OSCC. While the production of these SIBLINGs is independent of T, they correlate with oral location of tumor, cognate MMP expression, and for DSPP, the degree of tumor differentiation.

SIBLING expression patterns in duct epithelia reflect the degree of metabolic activity

The SIBLING (Small Integrin-Binding LIgand, N-linked Glycoprotein) family of secreted glycophosphoproteins includes bone sialoprotein (BSP), dentin matrix protein-1 (DMP1), dentin sialophosphoprotein (DSPP), osteopontin (OPN), and matrix extracellular phosphoglycoprotein (MEPE). For many years, they were thought in normal adults to essentially be limited to metabolically active mesenchymal cells that assembled the mineralized matrices of bones and teeth. Over the last decade they have also been upregulated in a variety of tumors. Three of these proteins (BSP, OPN, and DMP1) have been shown to interact with three matrix metalloproteinases (MMP-2, MMP-3, and MMP-9, respectively). Recently, all five SIBLINGs and their MMP partners when known were observed in specific elements of normal ductal epithelia in salivary gland and kidney. We have hypothesized that the SIBLINGs and their MMP partners may be expressed in ductal cells with high metabolic activity. In this paper, we show that all the SIBLINGs (except MEPE) and their MMP partners are expressed in the metabolically active epithelia of human eccrine sweat gland duct but not in the more passive ductal cells of the macaque (monkey) lacrimal gland. It is hypothesized that MEPE expression may be limited to cells involved in active phosphate transport. This manuscript contains online supplemental material at http://www.jhc.org. Please visit this article online to view these materials.

Human osteopetroses and the osteoclast V-H+-ATPase enzyme system

Osteopetroses are a heterogeneous group of human genetic diseases characterized by generalized increase in bone density due either to a decreased osteoclast population, defect in osteoclast function, or both. Current knowledge of the pathogenesis suggests defects that may be either intrinsic to osteoclast-monocyte lineage or extrinsic to the mesenchymal cells that support osteoblast ontogeny and activation. Four clinically distinct forms of human osteopetroses currently recognized are the infantile malignant autosomal recessive form, the intermediate autosomal recessive form, the adult benign autosomal dominant osteopetrosis type I, and the autosomal dominant osteopetrosis type II. Propensity to fracture is high in all types of osteopetrosis, and other characteristic clinical problems include hematologic and metabolic abnormalities, infections of affected bone, and neurologic sequela. Among the infantile malignant clinical forms 50-60% of patients present with defects in the OC116-KDa (also refers to ATP6i, TCIRGI, a3) subunit of the osteoclast vacuolar H+-ATPase (V-H+-ATPase) proton pump. Approaches that have been applied to the treatment of osteopetrosis include those aimed at stimulating host osteoclasts. These approaches however have met with little success, and it would appear that the future for the successful treatment of osteopetrosis lies with bone marrow transplantation. Various animal models mimicking some of the clinical subtypes of osteopetrosis have been generated in efforts to elicit further understanding of the pathogenesis. This review is an update on the various phenotypic presentations of human osteopetroses alongside their known animal models. Further studies on these animal models will not only expand our basic understanding of the molecular mechanisms of osteopetroses, but will also aid our ability to develop therapeutic means of intervention in diseases involving osteopetroses.

Renal expression of SIBLING proteins and their partner matrix metalloproteinases (MMPs)

BACKGROUND

Three members of the small integrin-binding ligand N-linked glycoprotein (SIBLING) family of proteins have recently been shown to bind and activate specific promatrix metalloproteinases (MMPs) and to overcome the inhibition of tissue inhibitors of MMPs (TIMPs). Although usually associated with mineralized tissues, we have shown that the SIBLINGs and their MMP partners, when known, are coexpressed in salivary gland ductal cells. The present study examined the expression patterns of both the SIBLINGs and their MMP partners in adult kidney.

METHODS

The expression patterns of all five SIBLINGs known to date, and their MMP partners were determined in monkey kidney using immunohistochemistry and in situ hybridization techniques.

RESULTS

Bone sialoprotein (BSP) and its partner, MMP-2, were coexpressed in both the proximal and distal tubules. Osteopontin, as previously shown, was expressed in the distal tubules while its partner MMP-3 was expressed in both the proximal tubule and distal tubles. Dentin matrix protein-1 (DMP1) and MMP-9 were coexpressed throughout the nephron, including both parietal cells of Bowman's capsule and the thin limb of the loop of Henle. Dentin sialophosphoprotein (DSPP) and matrix extracellular phosphoglycoprotein (MEPE) were expressed in the proximal tubule and distal tubule, and proximal tubule, respectively.

CONCLUSION

In contrast to salivary gland in which all SIBLINGs and their MMP partners were coexpressed throughout the length of the ducts, these proteins were differentially expressed within the normal adult nephron. We hypothesize that the cells use the SIBLING/MMP pairs in the normal turnover of cell surface proteins and/or pericellular matrix proteins such as those in basement membranes.

Expression of SIBLINGs and their partner MMPs in salivary glands

Three members of the SIBLING family of integrin-binding phosphoglycoproteins (bone sialoprotein, BSP; osteopontin, OPN; and dentin matrix protein-1, DMP1) were recently shown to bind with high affinity (nM) and to activate 3 different matrix metalloproteinases (MMP-2, MMP-3, and MMP-9, respectively) in vitro. The current study was designed to document the possible biological relevance of the SIBLING-MMP activation pathway in vivo by showing that these 3 SIBLINGs and their known MMP partners are co-expressed in normal adult tissue. BSP, OPN, and DMP1 were invariably co-expressed with their partner MMPs in salivary glands of humans and mice. The 2 SIBLING proteins without known MMP partners, dentin sialophosphoprotein (DSPP) and matrix extracellular phosphoglycoprotein (MEPE), were also expressed in salivary glands. Expression of all SIBLINGs in this normal, non-mineralizing epithelial tissue suggests that they serve at least one function in vivo other than directly promoting matrix mineralization--a function we hypothesize involves local activation of MMPs.

Bone Sialoprotein, Matrix Metalloproteinase 2, and v 3 Integrin in Osteotropic Cancer Cell Invasion

BACKGROUND

Bone sialoprotein (BSP) interacts separately with both matrix metalloproteinase 2 (MMP-2) and integrin alpha(v)beta3 and is overexpressed in many metastatic tumors. Its role in tumor biology, however, remains unclear. We investigated whether BSP enhances cancer cell invasiveness by forming a trimolecular complex with MMP-2 and cell-surface integrin alpha(v)beta3.

METHODS

Invasiveness of breast, prostate, lung, and thyroid tumor cell lines was measured with a modified Boyden chamber assay. Binding and co-localization of BSP, MMP-2, and integrin alpha(v)beta3 were investigated with immunoprecipitation and in situ hybridization. All statistical tests were two-sided.

RESULTS

Treatment with BSP increased invasiveness of many breast, prostate, lung, and thyroid cancer cells through Matrigel in a dose-dependent manner. BSP at 50 nM increased the invasiveness of SW-579 thyroid cancer cells (95.2 units, 95% confidence interval [CI] = 90.4 to 100 units) by approximately 10-fold compared with that of untreated control SW-579 cells (9.1 units, 95% CI = 5.7 to 12.5 units) (P<.001). Addition of an inactive mutated BSP, in which BSP's integrin-binding RGD tripeptide was altered, or addition of integrin alpha(v)beta3-blocking antibodies resulted in invasiveness equivalent to that of untreated cells. Inhibiting cellular MMP-2 activity with chemical inhibitors or a specific antibody also blocked BSP-enhanced invasiveness. Osteopontin and dentin matrix protein 1, proteins related to BSP that also bind integrin alpha(v)beta3 and form complexes with other MMPs (but not MMP-2), did not enhance invasiveness. Immunoprecipitation showed that a complex containing BSP, integrin alpha(v)beta3, and MMP-2 formed in vitro. Addition of BSP increased the amount of MMP-2 bound by cells in an integrin-dependent fashion. Co-expression of BSP, integrin alpha(v)beta3, and MMP-2 in papillary thyroid carcinoma cells was shown by in situ hybridization.

CONCLUSION

Cancer cells appear to become more invasive when BSP forms a cell-surface trimolecular complex by linking MMP-2 to integrin alpha(v)beta3.