Tine M. Søland

Molecular based treatment of oral cancer

This article has been retracted at the request of Oral Oncology and the co-authors. Please see http://www.elsevier.com/locate/withdrawalpolicy . Reason: The lead author, Jon Sudbo, has been found by the Investigating Commission (appointed in January 2006 by Rikshospitalet - Radiumhospitalet MC and the University of Oslo to investigate Dr Sudbos misconduct) to have fabricated and modified the data on which the analyses were based. The above mentioned Investigating Commission has determined that Dr Sudbo acted alone in fabricating the data. Dr Sudbo disputes the findings of the Investigating Commission. Reference: Ekbom A, Helgesen GEM, Lunde T, Tverdal A, Vollset SE, Simonsen S. Report from the Investigating Commission appointed by Rikshospitalet - Radiumhospitalet MC and the University of Oslo, January 18, 2006.

Nerve growth factor receptor (p75NTR) and pattern of invasion predict poor prognosis in oral squamous cell carcinoma

Aims:  To evaluate the expression of p75 neurotrophin receptor (p75NTR) in oral squamous cell carcinoma (OSCC). The results were related to tumour node metastasis (TNM) stage, World Health Organization (WHO) grade, invasive front grading (IFG) and prognosis.

Prognostic molecular markers in cancer - quo vadis?

Despite the tremendous number of studies of prognostic molecular markers in cancer, only a few such markers have entered clinical practise. The lack of clinical prognostic markers clearly reflects limitations in or an inappropriate approach to prognostic studies. This situation should be of great concern for the research community, clinicians and patients. In the present review, we evaluate immunohistochemical prognostic marker studies in oral squamous cell carcinomas (OSCC) from 2006 to 2012. We comment upon general issues such as study design, assay methods and statistical methods, applicable to prognostic marker studies irrespective of cancer type. The three most frequently studied markers in OSCC are reviewed. Our analysis revealed that most new molecular markers are reported only once. To draw conclusions of clinical relevance based on the few markers that appeared in more than one study was problematic due to between‐study heterogeneity. Currently, much valuable tissue material, time and money are wasted on irrelevant studies.

Induction of invasion in an organotypic oral cancer model by CoCl2, a hypoxia mimetic

Invasion is a hallmark of malignancy. The aim of this study was to develop an in vitro model that can be used for experimental studies of cancer cell invasion. The organotypic oral cancer model was constructed by growing oral squamous cell carcinoma (OSCC) cells on a collagen matrix in which normal human fibroblasts were incorporated. Immunohistochemical staining of the model showed that the expression of invasion-related molecules such as phosphorylated extracellular signal-regulated kinases 1 and 2 (p-ERK1/2), cyclooxygenase-2 (COX-2), p75(NTR), and hepatocyte growth factor receptor (Met) was similar to that seen in OSCC. Treatment of the model with cobalt chloride (CoCl(2)) to mimic hypoxic conditions increased cancer cell invasion, defined as the appearance of cancer cell islands protruding into the matrix. Models treated with CoCl(2) showed increased expression of p75(NTR) and laminin-5 in the cancer cells, and a more pronounced fragmentation of collagen IV in the basal membrane area, in contrast to models that were left untreated. The results indicate that the present model is well suited for studies on cancer cell invasion in the matrix and that the addition of CoCl(2) on day 3 of the experiment is indicated because it markedly increases the invasion and improves the model.

A study of phosphorylated ERK1/2 and COX-2 in early stage (T1-T2) oral squamous cell carcinomas.

BACKGROUND Histomorphological grading at the invasive front of oral squamous cell carcinomas (OSCCs) may provide useful prognostic information. In the present study, we investigated the presence and prognostic value of activated phosphorylated extracellular signal-regulated kinases 1 and 2 (p-ERK1/2) and cyclo-oxygenase-2 (COX-2) both at the invasive front and in central/superficial parts of OSCCs. METHODS Using immunohistochemistry, we assessed the presence of p-ERK1/2 and COX-2 in 53 early stage OSCCs. Clinical data were recorded prospectively. The end point was disease-free survival. RESULTS p-ERK1/2 staining was present in almost all tumours. The staining was mostly nuclear in the cells of the invasive front and either nuclear or nuclear/cytoplasmic in central/superficial tumour parts. COX-2 was observed in almost all tumours (98%) and the staining was often restricted to focal areas. Most tumours were COX-2 negative at the invasive front. The lowest P-value in survival analyses was P = 0.06 for p-ERK1/2 at the invasive front. COX-2, the histomorphological grading systems and TNM stage were of no prognostic value. CONCLUSION p-ERK1/2 was present in almost all tumours and p-ERK1/2 may be a prognostic marker at the invasive front of OSCCs. In early stage OSCCs, most tumours did not express COX-2 at the invasive front.

Nuclear and cytoplasmic expression of Met in oral squamous cell carcinoma and in an organotypic oral cancer model.

Met, the hepatocyte growth factor receptor, is important in transducing signals for tumour growth and metastasis. The aim of this study was to examine the pattern of Met expression and its value as a prognostic factor in oral squamous cell carcinomas (OSCCs). The material consisted of 53 OSCCs and five healthy controls from normal oral mucosa supplied with cell lines, 10 organotypic models supplied with oral cancer cells, and three organotypic models supplied with normal keratinocytes. Met protein expression was assessed by immunohistochemistry and western blotting. Met expression was scarce and limited to the basal layer in normal oral mucosa, but was more extensive in the tumours. Cytoplasmic expression of Met was found in the majority of the tumours, and nuclear expression was found in 72%, including a high fraction of the cells located at the invasive front. Organotypic models with normal or malignant oral cells yielded principally similar results as in the mucosa and the cancers, respectively. A smaller amount of Met immunoreactivity was detected, by western blotting, in the nuclear fraction of cultured oral cancer cells. In conclusion, Met was upregulated in OSCCs and was also found in the nucleus. However, Met was not a marker for prognosis in this study.

Scandinavian Fellowship for Oral Pathology and Oral Medicine: guidelines for oral pathology and oral medicine in the dental curriculum

In Scandinavia, as in many European countries, most patients consult their general dentist once a year or more. This gives the dentist a unique opportunity and an obligation to make an early diagnosis of oral diseases, which is beneficial for both the patient and the society. Thus, the dentist must have knowledge of clinical symptoms, local and systemic signs and clinical differential diagnoses to make an accurate diagnosis. The dentist must be competent in selecting appropriate diagnostic tests, for example, tissue biopsy and microbiological samples, and conducting them correctly, as well as in interpreting test results and taking appropriate action accordingly. Furthermore, the dentist must be aware of diseases demanding multidisciplinary cooperation and be able to recognise his/her professional limitation, and to refer to other specialists when required. The dental curriculum changes over time as new approaches, treatments and diagnostic possibilities develop. Likewise, the role of the dentist in the community changes and may vary in different countries. As members of the Scandinavian Fellowship for Oral Pathology and Oral Medicine and subject representatives of oral pathology and oral medicine, we feel obliged to contribute to the discussion of how the guidelines of the dental curriculum support the highest possible standards of dental education. This article is meant to delineate a reasonable standard of oral pathology and oral medicine in the European dental curriculum and to guide subject representatives in curriculum development and planning. We have created an advisory topic list in oral pathology and oral medicine.

Expression of the T‐cell‐specific adapter protein in oral epithelium

The multifunctional T-cell-specific adapter protein (TSAd) was originally described in T cells but is also expressed in epithelial cells from the respiratory tract and in endothelium. In this study, we found expression of TSAd messenger RNA (mRNA) and protein in both human and murine oral mucosal epithelium as well as in human primary oral keratinocyte cell cultures. In TSAd(-/-) mice, the mucosa and skin appeared macroscopically normal, but severe disturbances were observed in the fine structures of the basal membrane and intercellular epithelial spaces upon analysis using transmission electron microscopy. Oral epithelial cells from TSAd(-/-) mice displayed decreased migration compared with cells from wild-type mice, whereas overexpression of TSAd in a human epithelial cell line resulted in impaired proliferation. This study is the first to show that TSAd is expressed in normal oral mucosa, that it is important for the normal ultrastructural morphology of the epithelium and the basal membrane, and that it is involved in the migration and proliferation of oral keratinocytes.

Efficient extracellular vesicle isolation by combining cell media modifications, ultrafiltration, and size-exclusion chromatography

Extracellular vesicles (EVs) are a heterogeneous population of biological particles released by cells. They represent an attractive source of potential biomarkers for early detection of diseases such as cancer. However, it is critical that sufficient amounts of EVs can be isolated and purified in a robust and reproducible manner. Several isolation methods that seem to produce distinct populations of vesicles exist, making data comparability difficult. While some methods induce cellular stress that may affect both the quantity and function of the EVs produced, others involve expensive reagents or equipment unavailable for many laboratories. Thus, there is a need for a standardized, feasible and cost-effective method for isolation of EVs from cell culture supernatants. Here we present the most common obstacles in the production and isolation of small EVs, and we suggest a combination of relatively simple strategies to avoid these. Three distinct cell lines were used (human oral squamous cell carcinoma (PE/CA-PJ49/E10)), pancreatic adenocarcinoma (BxPC3), and a human melanoma brain metastasis (H3). The addition of 1% exosome-depleted FBS to Advanced culture media enabled for reduced presence of contaminating bovine EVs while still ensuring an acceptable cell proliferation and low cellular stress. Cells were gradually adapted to these new media. Furthermore, using the Integra CELLine AD1000 culture flask we increased the number of cells and thereby EVs in 3D-culture. A combination of ultrafiltration with different molecular weight cut-offs and size-exclusion chromatography was further used for the isolation of a heterogeneous population of small EVs with low protein contamination. The EVs were characterized by nanoparticle tracking analysis, immunoaffinity capture, flow cytometry, Western blot and transmission electron microscopy. We successfully isolated a significant amount of small EVs compatible with exosomes from three distinct cell lines in order to demonstrate reproducibility with cell lines of different origin. The EVs were characterized as CD9 positive with a size between 60–140 nm. We conclude that this new combination of methods is a robust and improved strategy for the isolation of EVs, and in particular small EVs compatible with exosomes, from cell culture media without the use of specialized equipment such as an ultracentrifuge.