Olaf Joseph Franciscus Schreurs

• Juvkam, Inga; Zlygosteva, Olga; Schreurs, Olaf Joseph Franciscus; Edin, Nina Frederike Jeppesen; Galtung, Hilde & Malinen, Eirik [Show all 7 contributors for this article] (2025). Regional atrophy, cellular plasticity, and regenerative potential in irradiated murine salivary glands. Acta Oncologica. ISSN 0284-186X. 64, p. 927–938. doi: 10.2340/1651-226x.2025.44012. Full text in Research Archive Show summary

  Background and purpose: Radiotherapy of head and neck cancer may cause detrimental late side effects such as fibrosis and hyposalivation. We investigated mouse salivary glands after fractionated irradiation, with the aim to elucidate cellular plasticity and potential regeneration. Methods: 12-week-old female C57BL/6JRj mice were irradiated with X-rays to a total dose of 66 Gy, given in 10 fractions over 5 days. The radiation field covered the oral cavity and major salivary glands. The submandibular (SMG), sublingual (SLG), and parotid glands (PG) were dissected at day 100 after finishing irradiation. Using different histological staining techniques, morphological, cellular, and molecular changes were investigated in irradiated and control SMG, SLG, and PG. Results: Atrophy of acinar cells was observed in irradiated SMG and SLG, but not in PG. Surprisingly, the acinar atrophy was confined to one region of each irradiated gland. These atrophic regions showed distinct cellular and molecular compositions compared to non-atrophic regions and control glands. Increased expression of the ductal cell markers keratin 5 and 19 (K5 and K19), along with increased percentages of proliferating myofibroblasts, fibroblasts, leukocytes, and acinar cells (Nkcc1+) were observed in the atrophic regions compared to controls. In addition, some of the K19+ and K5+ duct-like cells also co-expressed Nkcc1. Interpretation: Through a detailed histological assessment of the cellular and molecular changes in the major salivary glands of irradiated mice, we observed signs of cellular plasticity where ductal cells adopt an acinar cell phenotype upon irradiation. This suggests a regenerative potential of salivary glands after irradiation.

• Balta, Maria; Schreurs, Olaf Joseph Franciscus; Blix, Inger Johanne Schytte & Schenck, Karl (2024). The effect of resolvin D1<inf>n-3 DPA</inf> on primary oral epithelial cell migration in vitro. European Journal of Oral Sciences. ISSN 0909-8836. doi: 10.1111/eos.12981. Full text in Research Archive Show summary

  Specialized pro-resolving lipid mediators (SPMs) are known for their anti-inflammatory and pro-resolving actions. The aim of the present study was to find new functions of the SPM resolvin D1n-3 DPA (RvD1n-3 DPA) on oral epithelial cells. As a starting point, we used a dataset obtained by RNA high-throughput sequencing of oral epithelial cells exposed to TNF-α and RvD1n-3 DPA versus TNF-α alone. GOrilla enrichment analysis showed that the actin cytoskeleton was significantly overrepresented after adjustment for multiple hypothesis testing. As actin, amongst others, is closely related to cell migration, we then explored whether RvD1n-3 DPA can modulate oral epithelial cell migration. To this end, we used an in vitro cell migration model, including TNF-α treatment, to mimic an inflammatory cell state. The analysis revealed that RvD1n-3 DPA increased oral epithelial cell migration in the presence but not in the absence of TNF-α. Addition of RvD1n-3 DPA also induced F actin accumulation around the cell nucleus, indicating that RvD1n-3 DPA potentially can mediate processes of intracellular transport. This indicates that this lipid mediator may be a promising therapeutic candidate in oral mucosal wound healing.

• Sapkota, Dipak; Wang, Daxin; Schreurs, Olaf Joseph Franciscus; Vallenari, Evan Michael; Pandey, Sushma & Küntziger, Thomas M. [Show all 9 contributors for this article] (2024). Investigation of Roles of SLC38A1 in Proliferation and Differentiation of Mouse Tongue Epithelium and Expression in Human Oral Tongue Squamous Cell Carcinoma. Cancers. 16(2). doi: 10.3390/cancers16020405. Full text in Research Archive Show summary

  The aerobic glycolytic pathway, boosting lactate formation, and glutamine addiction are two hallmarks of cancer pathophysiology. Consistent with this, several cell membrane glutamine transporters, belonging to different solute carrier (SLC) families, have been shown to be upregulated in a cell-specific manner to furnish the cells with glutamine and glutamine-derived metabolic intermediates. Among them, the system A transporter Slc38a1 has a higher affinity for glutamine compared to other SLC transporters, and it undergoes highly multifaceted regulation at gene and protein levels. The current study aimed to investigate the functional role of Slc38a1 in the proliferation and maturation of the mouse tongue epithelium. Secondly, we aimed to examine the expression of SLC38A1 and its regulation in human tongue oral squamous cell carcinoma (OTSCC). Employing Slc38a1 wild-type and knockout mice, we showed that Slc38a1 was not directly linked to the regulation of the proliferation and differentiation of the mouse tongue epithelium. External transcriptomic datasets and Western blot analyses showed upregulation of SLC38A1 mRNA/protein in human OTSCC and oral cancer cell lines as compared to the corresponding controls. Further, an investigation of external datasets indicated that mechanisms other than the amplification of the SLC38A1 chromosomal locus or hypomethylation of the SLC38A1 promoter region might be important for the upregulation of SLC38A1 in OTSCC.

• Rykkelid, Anne Marit; Sinha, Priyanshu Manojkumar; Folefac, Charlemagne Asonganyi; Horsman, Michael R.; Sørensen, Brita Singers & Søland, Tine Merete [Show all 9 contributors for this article] (2024). Combination of proton- or X-irradiation with anti-PDL1 immunotherapy in two murine oral cancers. Scientific Reports. 14(1). doi: 10.1038/s41598-024-62272-z. Full text in Research Archive Show summary

  Combining radiation therapy with immunotherapy is a strategy to improve both treatments. The purpose of this study was to compare responses for two syngeneic head and neck cancer (HNC) tumor models in mice following X-ray or proton irradiation with or without immune checkpoint inhibition (ICI). MOC1 (immunogenic) and MOC2 (less immunogenic) tumors were inoculated in the right hind leg of each mouse (C57BL/6J, n = 398). Mice were injected with anti-PDL1 (10 mg/kg, twice weekly for 2 weeks), and tumors were treated with single-dose irradiation (5–30 Gy) with X-rays or protons. MOC2 tumors grew faster and were more radioresistant than MOC1 tumors, and all mice with MOC2 tumors developed metastases. Irradiation reduced the tumor volume in a dose-dependent manner. ICI alone reduced the tumor volume for MOC1 with 20% compared to controls, while no reduction was seen for MOC2. For MOC1, there was a clear treatment synergy when combining irradiation with ICI for radiation doses above 5 Gy and there was a tendency for X-rays being slightly more biologically effective compared to protons. For MOC2, there was a tendency of protons being more effective than X-rays, but both radiation types showed a small synergy when combined with ICI. Although the responses and magnitudes of the therapeutic effect varied, the optimal radiation dose for maximal synergy appeared to be in the order of 10–15 Gy, regardless of tumor model.

• Toközlü, Burcu; Sapkota, Dipak; Vallenari, Evan Michael; Schreurs, Olaf Joseph Franciscus & Søland, Tine Merete (2023). Cortactin expression in a Norwegian cohort of human papilloma virus negative oral squamous cell carcinomas of the mobile tongue. European Journal of Oral Sciences. ISSN 0909-8836. doi: 10.1111/eos.12925. Full text in Research Archive
• Sharma, Sunita; Khan, Qalbi; Schreurs, Olaf Joseph Franciscus; Sapkota, Dipak & Samuelsen, Jan Tore (2023). Investigation of biological effects of HEMA in 3D-organotypic co-culture models of normal and malignant oral keratinocytes. Biomaterial Investigations in Dentistry. 10(1), p. 98–108. doi: 10.1080/26415275.2023.2234400. Full text in Research Archive Show summary

  Several in vitro studies utilizing 2-dimensional (2D) cell culture systems have linked 2-hydroxyethyl methacrylate (HEMA) with cytotoxic effects in oral mucosa and dental pulp cells. Although such studies are invaluable in dissecting the cellular and molecular effects of HEMA, there is a growing interest in the utilization of appropriate 3-dimensional (3D) models that mimic the structure of oral mucosa. Using a previously characterized 3D-organotypic co-culture model, this study aimed to investigate the cellular and molecular effects of HEMA on a 3D-co-culture model consisting of primary normal oral keratinocyte (NOK) grown directly on top of collagen I gel containing primary oral fibroblasts (NOF). The second aim was to examine the suitability of a 3D-co-culture system consisting of oral squamous cell carcinoma (OSCC) cells as a model system to investigate the biological effects of HEMA. We demonstrated that HEMA treatment led to reduced viability of NOK, NOF and OSCC-cell lines in 2D-culture. The keratinocytes in 3D-co-cultures of NOK and OSCC-cells reacted similarly with respect to cell proliferation and activation of autophagy flux, to HEMA treatment. Nevertheless, NOK was found to be more susceptible to apoptosis following HEMA treatment than OSCC in 3D-co-cultures. These results indicate that 3D-organotypic co-cultures of NOK might represent an appropriate model system for the investigation of the biological effects of HEMA and other dental biomaterials. Given the challenges in obtaining primary cultures of NOK and issues associated with their rapid differentiation in culture, the possible use of OSCC cells as an alternative to NOK for 3D models represents an area for future research.

• Basnet, Suyog; Vallenari, Evan Michael; Maharjan, Urusha; Sharma, Sunita; Schreurs, Olaf Joseph Franciscus & Sapkota, Dipak (2023). An Update on S100A16 in Human Cancer. Biomolecules. 13(7). doi: 10.3390/biom13071070. Full text in Research Archive Show summary

  S100A16 is a member of the S100 protein family. S100A16 is expressed in a variety of human tissues, although at varying levels. S100A16 expression is especially high in tissues rich in epithelial cells. mRNA and protein levels of S100A16 have been reported to be differentially expressed in the majority of human cancers. Functionally, S100A16 has been linked to several aspects of tumorigenesis, for example, cell proliferation, differentiation, migration, invasion, and epithelial-mesenchymal transition (EMT). Accordingly, S100A16 has been suggested to have both tumour-promoting and suppressive roles in human cancers. S100A16-mediated cellular functions are suggested to be mediated by the regulation of various signaling pathways/proteins including EMT-related proteins E-cadherin and Vimentin, PI3K-AKT, p53, MMP1-1, MMP-2, MMP-9, JNK/p38, etc. In addition to the functional roles, expression of S100A16 has been suggested to have prognostic potential in various cancer types. The aims of this review are to summarise the expression profile, identify common molecular partners and functional roles, and explore the prognostic potential of S100A16 in human cancers.

• Søland, Tine Merete; Solhaug, Maren Bråten; Bjerkli, Inger-Heidi; Schreurs, Olaf Joseph Franciscus & Sapkota, Dipak (2022). The prognostic role of combining Krüppel-like factor 4 score and grade of inflammation in a Norwegian cohort of oral tongue squamous cell carcinomas. European Journal of Oral Sciences. ISSN 0909-8836. p. 1–11. doi: 10.1111/eos.12866. Full text in Research Archive Show summary

  Krüppel-like factor 4 (KLF4) is a zinc-finger transcription factor involved in inflammation, cancer development, and progression. However, the relationship between KLF4, inflammation, and prognosis in oral cancer is not fully understood. KLF4 expression levels were examined in a multicenter cohort of 128 oral squamous cell carcinoma (OSCC) specimens from the tongue (OTSCC) using immunohistochemistry. In two external KLF4 mRNA datasets (The Cancer Genome Atlas/The Genotype-Tissue Expression Portal), lower KLF4 mRNA expression was found in OSCC and head and neck squamous cell carcinomas (HNSCC) than in control oral epithelium. These data indicate that down-regulation of KLF4 mRNA is linked to OSCC/HNSCC progression. Using Cox-multivariate analysis, a significantly favorable 5-year disease-specific survival rate was observed for a subgroup of patients with a combination of high levels of KLF4 expression and inflammation. OSCC cell lines exposed to IFN-γ showed a significant upregulation of nuclear KLF4 expression, indicating a link between inflammation and KLF4 expression in OSCC. Overall, the current data suggest a functional link between KLF4 and inflammation. The combination of high KLF4 nuclear expression and marked/moderate stromal inflammation might be useful as a favorable prognostic marker for a subgroup of OTSCC patients.

• Balta, Maria G.; Schreurs, Olaf Joseph Franciscus; Halder, Rashi; Küntziger, Thomas M.; Sætre, Frank Ove & Blix, Inger Johanne Schytte [Show all 9 contributors for this article] (2022). RvD1n-3 DPA Downregulates the Transcription of Pro-Inflammatory Genes in Oral Epithelial Cells and Reverses Nuclear Translocation of Transcription Factor p65 after TNF-α Stimulation. International Journal of Molecular Sciences. ISSN 1661-6596. 23(23), p. 1–11. doi: 10.3390/ijms232314878. Full text in Research Archive Show summary

  Specialized pro-resolving mediators (SPMs) are multifunctional lipid mediators that participate in the resolution of inflammation. We have recently described that oral epithelial cells (OECs) express receptors of the SPM resolvin RvD1n-3 DPA and that cultured OECs respond to RvD1n-3 DPA addition by intracellular calcium release, nuclear receptor translocation and transcription of genes coding for antimicrobial peptides. The aim of the present study was to assess the functional outcome of RvD1n-3 DPA–signaling in OECs under inflammatory conditions. To this end, we performed transcriptomic analyses of TNF-a-stimulated cells that were subsequently treated with RvD1n-3 DPA and found significant downregulation of pro-inflammatory nuclear factor kappa B (NF-kB) target genes. Further bioinformatics analyses showed that RvD1n-3 DPA inhibited the expression of several genes involved in the NF-kB activation pathway. Confocal microscopy revealed that addition of RvD1n-3 DPA to OECs reversed TNF-a-induced nuclear translocation of NF-kB p65. Co-treatment of the cells with the exportin 1 inhibitor leptomycin B indicated that RvD1n-3 DPA increases nuclear export of p65. Taken together, our observations suggest that SPMs also have the potential to be used as a therapeutic aid when inflammation is established.

• Sapkota, Dipak; Vallenari, Evan Michael; Tamatam, Dhanalakshmi; Schreurs, Olaf Joseph Franciscus; Pandey, Sushma & Søland, Tine Merete [Show all 9 contributors for this article] (2022). Investigation of Cross-Reactivity of Anti-Ephrin-B2 Antibody to Other Ephrin-B Members in an Immunohistochemical Study in a Cohort of Oral Squamous Cell Carcinoma. Oral. ISSN 2673-6373. 2. doi: 10.3390/oral2020015. Full text in Research Archive Show summary

  Ephrin-B1,-B2 and -B3 proteins share a high degree of sequence similarity. Investigation of these proteins as putative prognostic markers in human cancers including oral squamous cell carcinoma (OSCC) has been limited by challenges in generating specific antibodies against them. The current study examined the reactivity of a polyclonal anti-human ephrin-B2 antibody (HPA008999) against ephrin-B proteins and investigated the prognostic significance of immunoreactivity of the same antibody at different intra-tumor sites in OSCC specimens. By amino acid sequence comparison, immunocytochemistry and Western blot analysis on cell lysates and precipitates from HEK-293T cells transfected with EFNB1, EFNB2, or EFNB3 expression constructs, we demonstrated that HPA008999 reacted to all ephrin-B proteins. Using immunohistochemistry (IHC) with the HPA008999 antibody in a cohort (n = 131) of OSCC, we showed high immunoreactivity at the tumor center, but not at the tumor invading front, was significantly associated with worse 5-year overall survival probabilities. In conclusion, the HPA008999 antibody reacted to all ephrin-B proteins and the immunoreactivity at the tumor center might be useful as a prognostic marker in OSCC. These data underscore the need for the investigation of antibodies for cross-reactivity to similar protein members for obtaining reliable and meaningful results in IHC based biomarker studies.

• Balta, Maria; Schreurs, Olaf Joseph Franciscus; Hansen, Trond Vidar; Tungen, Jørn Eivind; Vik, Anders & Glaab, Enrico [Show all 10 contributors for this article] (2022). Expression and function of resolvin RvD1n-3 DPA receptors in oral epithelial cells. European Journal of Oral Sciences. ISSN 0909-8836. 130:e12883(4), p. 1–10. doi: 10.1111/eos.12883. Full text in Research Archive Show summary

  Chronic inflammatory responses can inflict permanent damage to host tissues. Specialized pro-resolving mediators downregulate inflammation but also can have other functions. The aim of this study was to examine whether oral epithelial cells express the receptors FPR2/ALX and DRV1/GPR32, which bind RvD1n-3 DPA, a recently described pro-resolving mediator derived from omega-3 docosapentaenoic acid (DPA), and whether RvD1n-3 DPA exposure induced significant responses in these cells. Gingival biopsies were stained using antibodies to FPR2/ALX and DRV1/GPR32. Expression of FPR2/ALX and DRV1/GPR32 was examined in primary oral epithelial cells by qRT-PCR, flow cytometry, and immunofluorescence. The effect of RvD1n-3 DPA on intracellular calcium mobilization and transcription of beta-defensins 1 and 2, and cathelicidin was evaluated by qRT-PCR. FPR2/ALX and DRV1/GPR32 were expressed by gingival keratinocytes in situ. In cultured oral epithelial cells, FPR2/ALX was detected on the cell surface, whereas FPR2/ALX and DRV1/GPR32 were detected intracellularly. Exposure to RvD1n-3 DPA induced intracellular calcium mobilization, FPR2/ALX internalization, DRV1/GPR32 translocation to the nucleus, and significantly increased expression of genes coding for beta-defensin 1, beta-defensin 2, and cathelicidin. This shows that the signal constituted by RvD1n-3 DPA is recognized by oral keratinocytes and that this can strengthen the antimicrobial and regulatory potential of the oral epithelium.

• Solhaug, Maren Bråten; Schreurs, Olaf Joseph Franciscus; Schenck, Karl; Blix, Inger Johanne Schytte & Bækkevold, Espen Sønderaal (2021). Origin of langerin (CD207)-expressing antigen presenting cells in the normal oral mucosa and in oral lichen planus lesions. European Journal of Oral Sciences. ISSN 0909-8836. 130:e12835(1), p. 1–12. doi: 10.1111/eos.12835. Full text in Research Archive Show summary

  The number of langerin-expressing antigen-presenting cells is higher in oral lichen planus than in normal oral mucosa. However, langerin may be expressed by several functionally different lineages of antigen presenting cells (APCs), and this has important implications for our understanding of the pathogenesis of oral lichen planus. The aim of this study was to determine the origin of the langerin-expressing APCs. To this end, we examined oral mucosal biopsies from healthy persons and patients with oral lichen planus using multicolor immunofluorescence. In normal oral mucosa, a substantial fraction of Langerhans cells expressed Ki-67, indicating that steady-state oral mucosal Langerhans cells are at least partially maintained by self-renewal. In oral lichen planus, the numbers of Langerhans cells were higher but proliferation was not altered, indicating that the higher cell numbers appeared to depend on recruited dendritic cell (DC)-precursors. Moreover, we found a markedly higher number of langerin+ APCs within the lamina propria of oral lichen planus lesions. Such cells did not display monocyte- or macrophage markers, but rather showed a phenotype compatible with tissue-elicited IRF4+ cDC2. Detailed understanding of how the oral mucosal APC network is regulated and the functional capacities of the different ontogenies may identify novel treatment targets for oral lichen planus.

• Schreurs, Olaf Joseph Franciscus; Balta, Maria; Karatsaidis, Andreas & Schenck, Karl (2020). Composition of hemidesmosomes in basal keratinocytes of normal buccal mucosa and oral lichen planus. European Journal of Oral Sciences. ISSN 0909-8836. 128(5), p. 369–378. doi: 10.1111/eos.12732. Full text in Research Archive Show summary

  Oral lichen planus (OLP) is a chronic inflammatory disease displaying ultrastructural disturbances in epithelial hemidesmosomes. The expression of several key hemidesmosomal components in OLP as well as in normal buccal mucosa is, however, unknown. The aim of the study was therefore to examine intracellular and extracellular components involved in hemidesmosomal attachment, in OLP (n = 20) and in normal buccal mucosa (n = 10), by immunofluorescence. In normal buccal mucosa, laminin‐α3γ2, integrin‐α6β4, CD151, collagen α‐1(XVII) chain, and dystonin showed linear expression along the basal membrane, indicating the presence of type I hemidesmosomes. Plectin stained most epithelial cell membranes and remained unphosphorylated at S4642. In OLP, most hemidesmosomal molecules examined showed disturbed expression consisting of discontinuous increases, apicolateral location, and/or intracellular accumulation. Plectin showed S4642‐phosphorylation at the basement membrane, and deposits of laminin‐α3 and laminin‐γ2 were found within the connective tissue. The disturbed expression of hemidesmosomal proteins in OLP indicates deficient attachment of the basal cell layer, which can contribute to detachment and cell death of basal keratinocytes seen in the disease.

• Schreurs, Olaf Joseph Franciscus; Karatsaidis, Andreas; Balta, Maria; Grung, Bjarte; Hals, Else Kristine Breivik & Schenck, Karl (2020). Expression of keratins 8, 18, and 19 in epithelia of atrophic oral lichen planus. European Journal of Oral Sciences. ISSN 0909-8836. 128(1), p. 7–17. doi: 10.1111/eos.12666. Full text in Research Archive Show summary

  Keratins form intermediate filaments of the cytoskeleton in keratinocytes and have roles in cell structure, signaling, intracellular transport, and cell death. Oral lichen planus (OLP) is an oral inflammatory disease with derangements in basal keratinocytes and disruption of the basal membrane. Here, we focused on epithelial expression of keratins 8, 18, and 19 because these proteins are known to modulate cell death. Biopsies were taken from buccal oral mucosa of persons with normal oral mucosa (n = 10) or atrophic OLP (n = 10). Cultured normal oral keratinocytes (n = 4) showed expression of mRNA and protein for keratins 8, 18, and 19. Immunohistochemistry showed consistent staining for keratins 8 and 18 in basal keratinocytes of normal oral mucosa. In OLP, staining for keratin (K)8 was mostly negative and staining for K18 was weak. Keratin 19 was expressed irregularly in most biopsies of normal oral mucosa and not at all in OLP. Several mononuclear leukocytes in the cellular infiltrate showed membrane staining for K8 and K18. Positive staining for K16 confirmed partial collapse of the basal cell layer in OLP. The basal cell niche in OLP therefore appeared to be partly populated with keratinocytes demonstrating a higher degree of differentiation (K8− K18− K19− K16+); consequently, such areas may be more susceptible to the action of cell death factors released from the cell infiltrate as a result of lacking the protective, normal keratin present in the basal epithelial cell layer of normal oral mucosa.

• Søland, Tine Merete; Bjerkli, Inger-Heidi; Georgsen, Jeanette B; Schreurs, Olaf Joseph Franciscus; Jebsen, Peter Wilhelm & Laurvik, Helene [Show all 7 contributors for this article] (2020). High-risk human papilloma virus was not detected in a Norwegian cohort of oral squamous cell carcinoma of the mobile tongue. Clinical and Experimental Dental Research. 7(1), p. 70–77. doi: 10.1002/cre2.342. Full text in Research Archive Show summary

  Abstract Objectives: The presence of and the causative role of high-risk human papilloma virus (HPV) is a subject of controversy in oral squamous cell carcinoma (OSCC). The disagreement can be related to the misclassification of OSCC as oropharyngeal squamous cell carcinoma and/or lack of standard detection methods. This study aimed to examine the presence of transcriptionally active high-risk HPV in a homogenous Norwegian cohort of primary and second primary OSCC of the mobile tongue (oral tongue squamous cell carcinoma—OTSCC). Methods: Tissue microarrays containing formalin-fixed and paraffin-embedded cores of 146 OTSCC from the anterior 2/3 of the tongue (n = 128 primary and n = 18 second primary) from a multicentric Norwegian cohort were examined for the presence of high-risk HPV by DNA- and RNA-in situ hybridization (ISH) assays and p16 immunohistochemistry. Results: Transcriptionally active HPV (E6/E7 mRNA) was not identified in any of the OTSCC specimens. In parallel, no tumors were positive for HPV by DNA ISH. Although, 61 (42%) OTSCC demonstrated p16 positivity with varying staining intensity and subcellular localization, only two cases demonstrated strong and uniform p16-staining (both cytoplasmic and nuclear) in >70% of cancer cells. The absence of transcriptionally active high-risk HPV in this cohort of OTSCC indicates that high-risk HPV is an unlikely causative factor in the present material.

• Thorlakson, Hong Huynh; Engen, Stian André; Schreurs, Olaf Joseph Franciscus; Schenck, Karl & Blix, Inger Johanne S. (2017). Lysophophatidic acid induces expression of genes in human oral keratinocytes involved in wournd healing. Archives of Oral Biology. ISSN 0003-9969. 80, p. 153–159. doi: 10.1016/j.archoralbio.2017.04.008. Full text in Research Archive Show summary

  OBJECTIVE: Epithelial cells participate in wound healing by covering wounds, but also as important mediators of wound healing processes. Topical application of the phospholipid growth factor lysophosphatidic acid (LPA) accelerates dermal wound healing and we hypothesized that LPA can play a role in human oral wound healing through its effects on human oral keratinocytes (HOK). DESIGN: HOK were isolated from gingival biopsies and exposed to LPA. The LPA receptor profile, signal transduction pathways, gene expression and secretion of selected cytokines were analyzed. RESULTS: HOK expressed the receptors LPA1, LPA5 and LPA6 and LPA activated the ERK1/2, JNK and p38 intracellular pathways, substantiated by secretion of IL-6 and IL-8. The early (2h) and intermediate (6h) gene expression profiles of HOK after LPA treatment showed a wide array of regulated genes. The majority of the strongest upregulated genes were related to chemotaxis and inflammation, and became downregulated after 6h. At 6h, genes coding for factors involved in extracellular matrix remodeling and re-epithelialization became highly expressed. IL-36γ, not earlier known to be regulated by LPA, was strongly transcribed and translated but not secreted. CONCLUSIONS: After stimulation with LPA, HOK responded by regulating factors and genes that are essential in wound healing processes. As LPA is found in saliva and is released by activated cells after wounding, our results indicate that LPA has a favorable physiological role in oral wound healing. This may further point towards a beneficial role for application of LPA on oral surgical or chronic wounds.

• Engen, Stian André; Rørvik, Gro Herredsvela; Schreurs, Olaf Joseph Franciscus; Blix, Inger Johanne S. & Schenck, Karl (2017). The oral commensal Streptococcus mitis activates the aryl hydrocarbon receptor in human oral epithelial cells. International Journal of Oral Science. ISSN 1674-2818. 9(3), p. 145–150. doi: 10.1038/ijos.2017.17. Full text in Research Archive Show summary

  Streptococcus mitis (S. mitis) is a pioneer commensal bacterial species colonizing many of the surfaces of the oral cavity in healthy individuals. Yet, not much information is available regarding its interaction with the host. We used examination of its transcriptional regulation in oral keratinocytes to elucidate some of its potential roles in the oral cavity. Transcription factor analysis of oral keratinocytes predicted S. mitis-mediated activation of aryl hydrocarbon receptor (AhR). Activation and functionality of AhR was confirmed through nuclear translocation determined by immunofluorescence microscopy and real-time polymerase chain reaction with reverse transcription analysis of CYP1A1, the hallmark gene for AhR activation. Addition of Streptococcus mutans or Streptococcus gordonii did not induce CYP1A1 transcription in the keratinocyte cultures. Introduction of an AhR-specific inhibitor revealed that S. mitis-mediated transcription of CXCL2 and CXCL8 was regulated by AhR. Elevated levels of prostaglandin E2 (enzyme-linked immunosorbent assay) in supernatants from S. mitis-treated oral epithelial cells were also attenuated by inhibition of AhR activity. The observed AhR-regulated activities point to a contribution of S. mitis in the regulation of inflammatory responses and thereby to wound healing in the oral cavity. The concept that the oral commensal microbiota can induce AhR activation is important, also in view of the role that AhR has in modulation of T-cell differentiation and as an anti-inflammatory factor in macrophages.

• Schenck, Karl; Schreurs, Olaf Joseph Franciscus; Hayashi, Katsuhiko & Helgeland, Kristen (2017). The role of nerve growth factor (NGF) and its precursor forms in oral wound healing. International Journal of Molecular Sciences. ISSN 1661-6596. 18(2), p. 1–12. doi: 10.3390/ijms18020386. Full text in Research Archive Show summary

  Nerve growth factor (NGF) and its different precursor forms are secreted into human saliva by salivary glands and are also produced by an array of cells in the tissues of the oral cavity. The major forms of NGF in human saliva are forms of pro-nerve growth factor (pro-NGF) and not mature NGF. The NGF receptors tropomyosin-related kinase A (TrkA) and p75 neurotrophin receptor (p75NTR) are widely expressed on cells in the soft tissues of the human oral cavity, including keratinocytes, endothelial cells, fibroblasts and leukocytes, and in ductal and acinar cells of all types of salivary glands. In vitro models show that NGF can contribute at most stages in the oral wound healing process: restitution, cell survival, apoptosis, cellular proliferation, inflammation, angiogenesis and tissue remodeling. NGF may therefore take part in the effective wound healing in the oral cavity that occurs with little scarring. As pro-NGF forms appear to be the major form of NGF in human saliva, efforts should be made to study its function, specifically in the process of wound healing. In addition, animal and clinical studies should be initiated to examine if topical application of pro-NGF or NGF can be a therapy for chronic oral ulcerations and wounds.

• Engen, Stian André; Schreurs, Olaf Joseph Franciscus; Petersen, Fernanda Cristina; Blix, Inger Johanne S.; Bækkevold, Espen Sønderaal & Schenck, Karl (2017). The Regulatory Role of the Oral Commensal Streptococcus mitis on Human Monocytes. Scandinavian Journal of Immunology. ISSN 0300-9475. 87(2), p. 80–87. doi: 10.1111/sji.12636. Full text in Research Archive
• Schreurs, Olaf Joseph Franciscus; Karatsaidis, Andreas & Schenck, Karl (2016). Phenotypically non-suppressive cells predominate among FoxP3-positive cells in oral lichen planus. Journal of Oral Pathology & Medicine. ISSN 0904-2512. 45(10), p. 766–773. doi: 10.1111/jop.12447. Full text in Research Archive
• Thorlakson, Hong Huynh; Schreurs, Olaf Joseph Franciscus; Schenck, Karl & Blix, Inger Johanne S. (2016). Lysophosphatidic acid regulates adhesion molecules and enhances migration of human oral keratinocytes. European Journal of Oral Sciences. ISSN 0909-8836. 124(2), p. 164–171. doi: 10.1111/eos.12255. Full text in Research Archive
• Bjerkan, Louise; Schreurs, Olav Joseph F; Engen, Stian André; Jahnsen, Frode Lars; Bækkevold, Espen Sønderaal & Blix, Inger Johanne S. [Show all 7 contributors for this article] (2015). The short form of TSLP is constitutively translated in human keratinocytes and has characteristics of an antimicrobial peptide. Mucosal Immunology. ISSN 1933-0219. 8(1), p. 49–56. doi: 10.1038/mi.2014.41. Full text in Research Archive Show summary

  Thymic stromal lymphopoietin (TSLP) has multifaceted immunological functions ranging from maintenance of tolerance to induction of disease. Two human transcript variants of TSLP are described: a long form (variant 1; lfTSLP) consisting of four exons and an alternative, short form (variant 2; sfTSLP) that lacks two exons compared with variant 1. SfTSLP has not been described at the protein level or functionally studied. Here, we demonstrate that the human sfTSLP is the predominant form of TSLP, constitutively expressed at the mRNA and protein level in keratinocytes of oral mucosa and skin and in salivary glands, is released in saliva, and is not regulated in the same manner as the long form. Compared with lfTSLP, sfTSLP exhibits a markedly stronger antibacterial activity. Synthetic sfTSLP did not activate signal transducer and activator of transcription 5 (STAT5) signaling in CD1c+ dendritic cells nor interfered with STAT5 activation by lfTSLP. SfTSLP may, therefore, act as an antimicrobial peptide in the oral cavity and on the skin to create a defense barrier that aids in the control of both commensal and pathogenic microbes. The results show that the two translational products of the TSLP gene have a different expression and different biological properties, and emphasize the importance of analyzing the two TSLP isoforms separately.

• Næsse, Elsebeth Pernille; Schreurs, Olav Joseph F; Messelt, Edvard Berger; Hayashi, Katsuhiko & Schenck, Karl (2013). Distribution of nerve growth factor, pro-nerve growth factor, and their receptors in human salivary glands. European Journal of Oral Sciences. ISSN 0909-8836. 121(1), p. 13–20. doi: 10.1111/eos.12008. Full text in Research Archive Show summary

  Nerve growth factor (NGF) is a pluripotent mediator that is present in a range of human tissues. Nerve growth factor was originally considered important only in neuronal homeostasis and pathophysiology, but later it was also implicated in the pathophysiology of inflammation, epithelial differentiation, and wound healing. In this study, the distribution of nerve growth factor beta (NGF-b) and pro-NGF, and their receptors – tyrosine kinase A (TrkA) and p75NTR – was examined in human parotid, submandibular, sublingual, and labial salivary glands by immunohistochemistry. Intercalated, striated, and collecting-ducts in all gland types showed strong staining for pro-NGF but only weak cytoplasmic or sparse nuclear staining for NGF-b. Tyrosine kinase A was strongly expressed in the ducts of all gland types, whereas p75NTR expression was mainly confined to collecting ducts. In acini, no or only weak cytoplasmic staining was found for all markers, and some nuclei stained positive for NGF-b, pro-NGF, and TrkA. Western blotting of saliva showed secretion of several forms of pro-NGF, while no mature NGF-b was detected. Salivary pro-NGF may play a role in oral wound healing.

• Larsen, Helga Soppeland; Ruus, Ann-Kristin; Schreurs, Olav Joseph F & Galtung, Hilde Kanli (2010). Aquaporin 11 in the developing mouse submandibular gland. European Journal of Oral Sciences. ISSN 0909-8836. 118(1), p. 9–13. Full text in Research Archive
• Brusevold, Ingvild Johnsen; Husvik, Camilla; Schreurs, Olav Joseph F; Schenck, Karl; Bryne, Magne & Søland, Tine Merete (2010). Induction of invasion in an organotypic oral cancer model by CoCl2, a hypoxia mimetic. European Journal of Oral Sciences. ISSN 0909-8836. 118(2), p. 168–176. Full text in Research Archive
• Kolltveit, Kristin Melkevik; Schreurs, Olav Joseph F; Østrem, Janet M; Søland, Tine Merete; Khuu, Cuong & Berge, Tone [Show all 11 contributors for this article] (2010). Expression of the T-cell-specific adapter protein in oral epithelium. European Journal of Oral Sciences. ISSN 0909-8836. 118(2), p. 159–167. Full text in Research Archive Show summary

  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.

• Storesund, Trond; Schreurs, Olav Joseph F; Messelt, Edvard Berger; Kolltveit, Kristin Melkevik & Schenck, Karl (2009). Trefoil factor family 3 expression in the oral cavity. European Journal of Oral Sciences. ISSN 0909-8836. 117(6), p. 636–643. doi: 10.1111/j.1600-0722.2009.00679.x. Full text in Research Archive Show summary

  This study examined the expression, in oral keratinocytes and in the major and minor salivary glands, of Trefoil factor family 3 (TFF3) peptide. Trefoil factor family 3 messenger RNA (mRNA) and peptide were detected in cultures of normal oral keratinocytes by quantitative real-time polymerase chain reaction (PCR) and western blotting, respectively. Trefoil factor family 3 was found, by immunohistochemical analyses, to be expressed in the basal layers of the oral mucosal epithelium. In salivary glands, immunohistochemical staining showed that TFF3 peptide expression was strongest in the mucous acini of the submandibular and the small salivary glands. Serous cells in the same glands showed weak staining. In the parotid gland, many serous acini showed weak positive staining, while other areas did not. In all glands examined, the intercalated, striated, and collecting ducts were moderately TFF3-positive. Double immunostaining confirmed that mucous (MUC5B positive) cells were moderately or strongly positive for TFF3 and that some serous (MUC7 positive) cells showed restricted TFF3 expression, mostly in a granular pattern. The prevalence of the TFF3 peptide in the salivary secretions of healthy volunteers was detected by western blotting of saliva from minor salivary glands (four of five) and the parotid gland (one of five) and of mixed submandibular/sublingual saliva (five of five). In conclusion, the submandibular and small salivary glands appear to be the major producers of oral TFF3, but duct cells of all glands and keratinocytes of the oral mucosa may also contribute as sources of TFF3 in the oral cavity.

• Hayashi, Katsuhiko; Karatsaidis, Andreas; Schreurs, Olav; Bjørnland, Tore; Sugisaki, Masashi & Schenck, Karl (2008). NGF and its receptors TrkA and p75(NTR) in the epithelium of oral lichen. Journal of Oral Pathology & Medicine. ISSN 0904-2512. 37(4), p. 241–248. doi: 10.1111/j.1600-0714.2007.00627.x. Full text in Research Archive
• Karatsaidis, Andreas; Hayashi, Katsuhiko; Schreurs, Olav; Helgeland, Kristen & Schenck, Karl (2007). Survival signalling in keratinocytes of erythematous oral lichen planus. Journal of Oral Pathology & Medicine. ISSN 0904-2512. 36(4), p. 215–222. doi: 10.1111/j.1600-0714.2007.00519.x. Full text in Research Archive
• Hayashi, Katsuhiko; Storesund, T; Schreurs, O; Khuu, C; Khuu, Cuong & Husvik, C [Show all 10 contributors for this article] (2007). Nerve growth factor beta/pro-nerve growth factor and their receptors in normal human oral mucosa. European Journal of Oral Sciences. ISSN 0909-8836. 115(5), p. 344–354. doi: 10.1111/j.1600-0722.2007.00480.x. Full text in Research Archive
• Karatsaidis, Andreas; Schreurs, Olav Joseph F; Axell, Tonny; Helgeland, K & Schenck, Karl (2004). Identity of TUNEL-positive cells in the oral buccal epithelium of normal mucosa and lichen lesions. Journal of Oral Pathology & Medicine. ISSN 0904-2512. 33(5), p. 264–268. Full text in Research Archive
• Karatsaidis, Andreas; Schreurs, Olav Joseph F; Helgeland, Kristen; Axell, Tonny & Schenck, Karl (2003). Erythematous and reticular forms of oral lichen planus and oral lichenoid reactions differ in pathological features related to disease activity. Journal of Oral Pathology & Medicine. ISSN 0904-2512. 32(5), p. 275–281. Full text in Research Archive
• Næsse, Elsbeth Pernille; Schreurs, Olav Joseph F; Helgeland, Kristen; Schenck, Karl & Steinsvoll, Svein E B (2003). Matrix metalloproteinases and their inhibitors in gingival mast cells in persons with and without human immunodeficiency virus infection. Journal of Periodontal Research. ISSN 0022-3484. 38(6), p. 575–582. Full text in Research Archive
• Karatsaidis, Andreas; Schreurs, Olav Joseph F; Axell, Tonny; Helgeland, Kristen & Schenck, Karl (2003). Inhibition of the transforming growth factor-beta/Smad signaling pathway in the epithelium of oral lichen. Journal of Investigative Dermatology. ISSN 0022-202X. 121(6), p. 1283–1290. Full text in Research Archive
• Dellacasagrande, Jerome; Schreurs, Olav Joseph F; Hofgaard, Peter Olaf; Omholt, Hilde; Steinsvoll, Svein E B & Schenck, Karl [Show all 8 contributors for this article] (2003). Liver metastasis of cancer facilitated by chemokine receptor CCR6. Scandinavian Journal of Immunology. ISSN 0300-9475. 57(6), p. 534–544. Full text in Research Archive
• Yuan, Zuan-Ning; Schreurs, Olav Joseph F; Gjermo, Per E; Helgeland, Kristen & Schenck, Karl (1999). Topical distribution of Fc-gamma, Fc-gammaRII and Fc-gammaRIII in inflamed human gingiva. Journal of Clinical Periodontology. ISSN 0303-6979. 26, p. 441–447. Full text in Research Archive
• Myint, Maung Maung; Odden, Kåre; Schreurs, Olav Joseph F; Halstensen, Trond Sundby & Schenck, Karl (1999). The gingival plasma cell infiltrate in HIV-positive patients with periodontitis is disorganized. Journal of Clinical Periodontology. ISSN 0303-6979. 26, p. 358–365. Full text in Research Archive Show summary

  Patients infected with the human immunodeficiency virus (HIV) are highly susceptible to chronic marginal periodontitis (CMP) and the lesion is generally characterized by abundant plasma cell infiltration. HIV-induced reduction of CD4+ T cells may indirectly affect local production of immunoglobulins (Ig). Gingival biopsies taken from 10 HIV+ and 12 HIV- control patients with CMP were washed, fixed in ethanol and embedded in paraffin. Sections were examined after immunohistochemical staining with monoclonal antibodies against IgA, IgA1-2, IgG, IgG1-4, IgM and IgE. Ig-containing cells were counted in 3 separate connective tissue zones (subjacent to pocket epithelium, central zone and subjacent to oral epithelium). HIV+ patients showed a remarkably increased density of all Ig-containing cells in the connective tissue zone subjacent to the oral epithelium (p<0.05) and a lower % of IgG2+ cells in the entire gingival section (p<0.05). In HIV+ patients, the density of IgG-containing cells in the gingiva was strongly correlated with the serum IgG concentration. The altered topical distribution might imply impaired restriction of the inflammatory lesion, additional antigenic challenges by unusual microorganisms in the oral cavity, or be secondary to HIV-induced dysregulation of the B-cell system.

• Schenck, Karl; Schreurs, Olav Joseph F & Helgeland, Kristen (1997). Apoptose - hvorfor vi ikke blir født med hale. NOFs Tidende. 107, p. 2–8. Full text in Research Archive
• Schreurs, Olav Joseph F; Halstensen, Trond Sundby; Dembic, Zlatko; Bogen, Bjarne & Schenck, Karl (1997). TUNEL combined with staining for epithelial cellmarker permits unambiguous localization of apoptic cells in murine thymus. Biochemica. ISSN 0946-1310. 4, p. 19–21. Full text in Research Archive

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• Rykkelid, Anne Marit; Sinha, Priyanshu Manojkumar; Folefac, Charlemagne Asonganyi; Horsman, Michael R.; Sørensen, Brita Singers & Søland, Tine Merete [Show all 9 contributors for this article] (2024). Correction to: Combination of proton- or X-irradiation with anti-PDL1 immunotherapy in two murine oral cancers (Scientific Reports, (2024), 14, 1, (11569), 10.1038/s41598-024-62272-z). Scientific Reports. 14(1). doi: 10.1038/s41598-024-66148-0. Full text in Research Archive
• Bhattarai, Bishwa Prakash; Søland, Tine Merete; Schreurs, Olaf Joseph Franciscus; Hasséus, Bengt & Sapkota, Dipak (2024). Expression of Cell Cycle Regulating Proteins in Oral Leukoplakia. Full text in Research Archive
• Liskiewicz, Krystyna Anna; Araya, Feven Tesfaldet; Vallenari, Evan Michael; Parajuli, Himalaya; Ramstad, Silje & Schreurs, Olaf Joseph Franciscus [Show all 8 contributors for this article] (2023). Cyclic-di-adenosine monophosphate’s effect on virulence of Streptococcus mitis CCUG 31611. Full text in Research Archive
• Rykkelid, Anne Marit; sinha, Priyanshu; Folefac, Charlemagne; Horsman, Michael; Sørensen, Brita Singers & Søland, Tine Merete [Show all 9 contributors for this article] (2023). Synergistic effects of combining proton- or X-irradiation with anti-PDL1 immunotherapy in two murine oral cancers. Full text in Research Archive
• Rykkelid, Anne Marit; sinha, Priyanshu; Folefac, Charlemagne; Horsman, Michael; Sørensen, Brita Singers & Søland, Tine Merete [Show all 9 contributors for this article] (2023). Synergistic effects of combining proton- or X-irradiation with anti-PDL1 immunotherapy in two murine oral cancers. Full text in Research Archive
• Schreurs, Olaf Joseph Franciscus; Karatsaidis, Andreas & Schenck, Karl (2019). Deficient expression of keratin 8 and 18 in epithelia of oral lichen planus. Full text in Research Archive
• André, Engen Stian; Schreurs, Olaf Joseph Franciscus; Fernanda, Petersen; Blix, Inger Johanne S.; S., Bækkevold Espen & Schenck, Karl (2018). The regulatory role of the oral commensal Streptococcus mitis on human monocytes. Full text in Research Archive
• Rørvik, Gro Herredsvela; Schreurs, Olaf Joseph Franciscus; Engen, Stian; Blix, Inger Johanne S.; Petersen, Fernanda Cristina & Schenck, Karl (2017). Antibody reactivity to the oral commensal Streptococcus mitis in serum and saliva. Full text in Research Archive
• Engen, Stian; Schreurs, Olaf Joseph Franciscus; Petersen, Fernanda Cristina; Blix, Inger Johanne S.; Bækkevold, Espen Sønderaal & Schenck, Karl (2017). Regulation of human monocytes by the oral commensal Streptococcus mitis: a role for PGE2? Full text in Research Archive
• Schreurs, Olaf Joseph Franciscus; Karatsaidis, Andreas & Schenck, Karl (2017). Altered change in K8 and K18 epithelial expression in oral lichen planus. Full text in Research Archive
• Hayashi, Katsuhiko; Næsse, Elsbeth Pernille; Schreurs, Olav Joseph F; Messelt, Edvard Berger; Sugisaki, Masashi & Schenck, Karl (2013). Distribution of NGF and its receptors in human salivary glands. Full text in Research Archive
• Brusevold, Ingvild Johnsen; Husvik, Camilla; Schreurs, Olav Joseph F; Schenck, Karl; Bryne, Magne & Søland, Tine Merete (2010). Induction of invasion in an organotypic oral cancer model by cobalt chloride, a hypoxia mimetic. European Journal of Cancer. ISSN 0959-8049. 8(5), p. 149–149. Full text in Research Archive
• Brusevold, Ingvild Johnsen; Husvik, Camilla; Schreurs, Olav Joseph F; Schenck, Karl; Bryne, Magne & Søland, Tine Merete (2010). Induction of invasion in an organotypic oral cancer model by cobalt chloride, a hypoxia mimetic. Full text in Research Archive
• Schreurs, Olav Joseph F; Schenck, Karl & Kolltveit, Kristin Melkevik (2009). FoxP3+ cell densities in oral lichen planus differ according to disease activity. Full text in Research Archive
• Søland, Tine Merete; Brusevold, Ingvild Johnsen; Husvik, Camilla; Schreurs, Olav Joseph F; Schenck, Karl & Bryne, Magne (2008). Manipulation of invasion in a 3D-co-culture organotypic oral cancer model. Full text in Research Archive
• Karatsaidis, Andreas; Hayashi, Katsuhiko; Schreurs, Olav Joseph F; Helgeland, Kristen & Schenck, Karl (2007). Protection against apoptosis in keratinocytes of erythematous oral lichen planus lesions. Full text in Research Archive
• Hayashi, Katsuhiko; Storesund, Trond; Schreurs, Olav Joseph F; Khuu, Cuong; Husvik, Camilla & Karatsaidis, Andreas [Show all 8 contributors for this article] (2007). NGF-ß/proNGF and their receptors in normal human oral mucosa. Full text in Research Archive
• Hayashi, Katsuhiko; Karatsaidis, Andreas; Schreurs, Olav Joseph F; Sugisaki, Masashi & Schenck, Karl (2007). NGF and Its Receptors TrkA and p75NTR in Oral Lichen. Full text in Research Archive
• Hayashi, Katsuhiko; Storesund, Trond; Schreurs, Olav Joseph F; Khuu, Cuong; Husvik, Camilla & Karatsaidis, Andreas [Show all 8 contributors for this article] (2007). NGF-beta/proNGF and their receptors in normal human oral mucosa. Virchows Archiv. ISSN 0945-6317. 451, p. 545–546. Full text in Research Archive
• Søland, Tine Merete; Schreurs, Olav Joseph F; Husvik, Camilla; Clausen, Ole Petter Fraas; Boysen, Morten Ebbe & Sudbø, Jon [Show all 7 contributors for this article] (2004). COX-2, APC and beta-catenin in the invasive front of oral squamous cell carcinomas and their relation to prognosis. Full text in Research Archive
• Søland, Tine Merete; Schreurs, Olav Joseph F; Husvik, Camilla; Koppang, Hanna Strømme & Bryne, Magne (2003). Selective COX-2 up-regulation in DNA aneuploid oral precancers; an opportunity for targeted preventive treatment of oral cancer. Full text in Research Archive
• Søland, Tine Merete; Sudbø, Jon; Schreurs, Olav Joseph F; Husvik, Camilla; Koppang, Hanna Strømme & Bryne, Magne (2003). Selective COX-2 up-regulation in DNA aneuploid oral precancers: an opportunity for targeted preventive treatment of oral cancers? Full text in Research Archive
• Kolltveit, Kristin Melkevik; Næsse, Elsbeth Pernille; Schreurs, Olav Joseph F; Helgeland, Kristen; Schenck, Karl & Steinsvoll, Svein E B (2002). Mast cells - Mediators of Rapid Matrix Degradation in Periodontitis? Full text in Research Archive
• Steinsvoll, Svein E B; Kolltveit, Kristin Melkevik; Næsse, Elsbeth Pernille; Schreurs, Olav Joseph F; Helgeland, Kristen & Schenck, Karl (2002). Mast Cells - Mediators of Rapidly Progressing Periodontitis in HIV+ Patients? Full text in Research Archive
• Næsse, Elsbeth Pernille; Schreurs, Olav Joseph F; Helgeland, Kristen; Schenck, Karl & Steinsvoll, Svein E B (2001). Mast Cells in Periodontitis Express Strongly Matrixmetalloproteinases. Full text in Research Archive
• Karatsaidis, Andreas; Schreurs, Olav Joseph F; Helgeland, Kristen; Axell, Tonny & Schenck, Karl (2001). Transforming growth factor-b (TGF-b1) epithelial expression in oral lichen planus and lichenoid reactions. An immuno-histochemical study. Full text in Research Archive
• Karatsaidis, Andreas; Schreurs, Olav Joseph F; Helgeland, Kristen; Axell, Tonny & Schenck, Karl (2001). Transforming growth factor-b (TGF-b1) epithelial expression in oral lichen planus and lichenoid reactions. An immuno-histochemical study. Full text in Research Archive
• Næsse, Elsbeth Pernille; Schreurs, Olav Joseph F; Helgeland, Kristen; Schenck, Karl & Steinsvoll, Svein E B (2001). Mast Cells - Mediators of Periodontal Tissue Destruction in HIV+ patients? Full text in Research Archive
• Karatsaidis, Andreas; Schreurs, Olav Joseph F; Helgeland, Kristen; Axell, Tonny & Schenck, Karl (2001). Transforming growth factor-b (TGF-b1) epithelial expression in oral lichen planus and lichenoid reactions. An immuno-histochemical study. Full text in Research Archive
• Karatsaidis, Andreas; Schreurs, Olav Joseph F; Helgeland, Kristen; Axell, Tonny & Schenck, Karl (2001). Transforming growth factor-b (TGF-b1) epithelial expression in oral lichen planus and lichenoid reactions. An immuno-histochemical study. Full text in Research Archive
• Steinsvoll, Svein E B; Schreurs, Olav Joseph F; Helgeland, Kristen & Schenck, Karl (2000). Mast cell matrix metalloproteinases - potential mediators of periodontal tissue destruction in HIV+ patients. Full text in Research Archive
• Næsse, Elsbeth Pernille; Schreurs, Olav Joseph F; Helgeland, Kristen; Schenck, Karl & Steinsvoll, Svein E B (2000). Mast Cells in Periodontitis Revisited: More than Meets the Eye ? Full text in Research Archive
• Steinsvoll, Svein E B; Schreurs, Olav Joseph F; Helgeland, Kristen & Schenck, Karl (1999). Tissue inhibitor of matrixmetalloproteinases-1 (TIMP-1) and matrix metalloproteinase (MMP)-1, -2, -9 are increased and co-expressed with transforming growth factor-&#61538;1 (TGF-&#61538;1) in inflamed periodontal tissue. Full text in Research Archive
• Steinsvoll, Svein E B; Schreurs, Olav Joseph F; Helgeland, Kristen & Schenck, Karl (1999). Expression of Matrix Metalloproteinases (MMPs), Inducers and Inhibitors in Chronically Inflamed Gingiva. Full text in Research Archive
• Yuan, Zuan-Ning; Schreurs, Olav Joseph F; Gjermo, Per E; Helgeland, Kristen & Schenck, Karl (1998). "Topical distribution of FcgRI, and FcgRII in inflamed human gingiva". Full text in Research Archive
• Schenck, Karl; Schreurs, Olav Joseph F & Helgeland, Kristen (1996). Nitrogenoksyd (NO) - et lite molekyl med et stort virkefelt. Den norske tannlegeforenings Tidende. ISSN 0029-2303. 106, p. 132–135. Full text in Research Archive
• Bryne, Magne; Kjærheim, Åsmund & Schreurs, Olav Joseph F (1992). Karbohydrater på celleoverflater er involvert i en rekke biologiske prosesser. Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 22(112), p. 2859–2862. Full text in Research Archive
• Bryne, Magne; Thrane, Per Stanley; Schreurs, Olav Joseph F & Dabelsteen, E. (1991). Munnhulekreft. Prognostiske aspekter. Den norske tannlegeforenings Tidende. ISSN 0029-2303. 101, p. 338–342. Full text in Research Archive
• Schreurs, Olaf Joseph Franciscus (2021). Studies on oral lichen planus: Cell biology and pathological tissue changes. Universitetet i Oslo. ISSN 9788283270532. Full text in Research Archive

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