Biomarker discovery for practice of precision medicine in hypopharyngeal cancer: a theranostic study on response prediction of the key therapeutic agents.

BACKGROUND: Hypopharyngeal cancer is a relatively rare malignancy with poor prognosis. Current chemotherapeutic algorithm is still far from personalized medicine, and the identification of the truly active therapeutic biomarkers and/or targets is eagerly awaited. METHODS: Venturing to focus on the conventional key chemotherapeutic drugs, we identified the most correlative genes (and/or proteins) with cellular sensitivity to docetaxel (TXT), cisplatin (CDDP) and 5-fluorouracil (5-FU) in the expression levels, through 3 steps approach: genome-wide screening, confirmation study on the quantified expression levels, and knock-down and transfection analyses of the candidates. The probable action pathways of selected genes were examined by Ingenuity Pathway Analysis using a large-scale database, The Cancer Genome Atlas. RESULTS: The first genome-wide screening study derived 16 highly correlative genes with cellular drug sensitivity in 15 cell lines (|R| > 0.8, P < 0.01 for CDDP and 5-FU; |R| > 0.5, P < 0.05 for TXT). Among 10 genes the observed correlations were confirmed in the quantified gene expression levels, and finally knock-down and transfection analyses provided 4 molecules as the most potent predictive markers-AGR2 (anterior gradient 2 homolog gene), and PDE4D (phosphodiesterase 4D, cAMP-specific gene) for TXT; NINJ2 (nerve Injury-induced protein 2); CDC25B (cell division cycle 25 homolog B gene) for 5-FU- in both gene and protein expression levels. Overexpression of AGR2, PDE4D signified worse response to TXT, and the repressed expression sensitized TXT activity. Contrary to the findings, in the other 2 molecules, NINJ2 and CDC25, there observed opposite relationship to cellular drug response to the relevant drugs. IPA raised the potential that each selected molecule functionally interacts with main action pathway (and/or targets) of the relevant drug such as tubulin ß chain genes for TXT, DNA replication pathway for CDDP, and DNA synthesis pathway and thymidylate synthetase gene for 5-FU. CONCLUSION: We newly propose 4 molecules -AGR2, PDE4D,NINJ2 and CDC25B) as the powerful exploratory markers for prediction of cellular response to 3 key chemotherapeutic drugs in hypopharyngeal cancers and also suggest their potentials to be the therapeutic targets, which could contribute to the development of precision medicine of the essential chemotherapy in hypopharyngeal patients. (339 words).

Cancer cell line microarray as a novel screening method for identification of radioresistance biomarkers in head and neck squamous cell carcinoma.

BACKGROUND: Currently, no clinically useful biomarkers for radioresistance are available in head and neck squamous cell carcinoma (HNSCC). This study assesses the usefulness of Cell Line Microarray (CMA) method to enhance immunohistochemical screening of potential immunohistochemical biomarkers for radioresistance in HNSCC cell lines. METHODS: Twenty-nine HNSCC cell lines were cultured, cell pellets formalin-fixed, paraffin-embedded, and arrayed. Radioresistance features of the cell lines were combined to immunohistochemical stains for p53, NDFIP1, EGFR, stem cell marker Oct4, and PP2A inhibitor CIP2A. RESULTS: Expression of p53, EGFR or CIP2A did not indicate intrinsic radioresistance in vitro. Stem cell marker Oct4 nuclear positivity and NDFIP1 nuclear positivity was correlated with increased intrinsic radioresistance. CONCLUSION: The usefulness of CMA in analysis of HNSCC cell lines and discovery of biomarkers is demonstrated. CMA is very well adapted to both testing of antibodies in a large panel of cell lines as well as correlating staining results with other cell line characteristics. In addition, CMA-based antibody screening proved an efficient and relatively simple method to identify potential radioresistance biomarkers in HNSCC.

Head and neck squamous cell carcinoma cell lines have an immunomodulatory effect on macrophages independent of hypoxia and toll-like receptor 9.

BACKGROUND: A low tissue oxygen level, < 1% O2, is a typical characteristic inside of solid tumors in head and neck cancer (HNSCC) affecting a wide array of cell populations, such as macrophages. However, the mechanisms of how hypoxia influences macrophages are not yet fully elucidated. Our research aimed to study the effect of soluble mediators produced by hypoxic cancer cells on macrophage polarization. Furthermore, we studied the effect of a hypoxic microenvironment on the expression of tumorigenic toll-like receptor 9 (TLR9) and the consecutive macrophage polarization. METHODS: Conditioned media (CMNOX or CMHOX) from cell lines UT-SCC-8, UT-SCC-74A, FaDu, MDA-MB-231 and HaCat cultured under normoxic (21% O2) and hypoxic (1% O2) conditions were used to polarize human monocyte-derived macrophages. Macrophage polarization was measured by flow cytometry and the production of cytokine mRNA using Taqman qPCR. To study the role of TLR9 in macrophage polarization, the lentiviral CRISPR/Cas9 method was used to establish a stable FaDuTLR9def clone. RESULTS: Our results demonstrate that the soluble mediators produced by the cancer cells under normoxia polarize macrophages towards a hybridized M1/M2a/M2c phenotype. Furthermore, the results suggest that hypoxia has a limited role in altering the array of cancer-produced soluble factors affecting macrophage polarization and cytokine production. Our data also indicates that increased expression of TLR9 due to hypoxia in malignant cells does not markedly influence the polarization of macrophages. TLR9 transcriptional response to hypoxia is dissimilar to a HIF1-α-regulated LDH-A. This may indicate a context-dependent expression of TLR9 under hypoxia. CONCLUSIONS: HNSCC cell lines affect both macrophage activity (polarization) and functionality (cytokines), but with exception to iNOS expression, the effects appear independent of hypoxia and TLR9.

The critical effects of matrices on cultured carcinoma cells: Human tumor-derived matrix promotes cell invasive properties.

The interaction between squamous cell carcinoma (SCC) cells and the tumor microenvironment (TME) plays a major role in cancer progression. Therefore, understanding the TME is essential for the development of cancer therapies. We used four (primary and metastatic) head and neck (HN) SCC cell lines and cultured them on top of or within 5 matrices (mouse sarcoma-derived Matrigel®, rat collagen, human leiomyoma-derived Myogel, human fibronectin and human fibrin). We performed several assays to study the effects of these matrices on the HNSCC behavior, such as proliferation, migration, and invasion, as well as cell morphology, and molecular gene profile. Carcinoma cells exhibited different growth patterns depending on the matrix. While fibrin enhanced the proliferation of all the cell lines, collagen did not. The effects of the matrices on cancer cell migration were cell line dependent. Carcinoma cells in Myogel-collagen invaded faster in scratch wound invasion assay. On the other hand, in the spheroid invasion assay, three out of four cell lines invaded faster in Myogel-fibrin. These matrices significantly affected hundreds of genes and a number of pathways, but the effects were cell line dependent. The matrix type played a major role in HNSCC cell phenotype. The effects of the ECMs were either constant, or cell line dependent. Based on these results, we suggest to select the most suitable matrix, which provides the closest condition to the in vivo TME, in order to get reliable results in in vitro experiments.

Elevated TLR5 expression in vivo and loss of NF-κΒ activation via TLR5 in vitro detected in HPV-negative oropharyngeal squamous cell carcinoma.

In oropharyngeal squamous cell carcinoma (OPSCC), the expression pattern of toll-like receptors (TLRs), in comparison between human papillomavirus (HPV)-positive and -negative tumors differs. TLRs control innate immune responses by activating, among others, the nuclear factor-κΒ (NF-κΒ) signaling pathway. Elevated NF-κΒ activity is detectable in several cancers and regulates cancer development and progression. We studied TLR5 expression in 143 unselected consecutive OPSCC tumors, and its relation to HPV-DNA and p16 status, clinicopathological parameters, and patient outcome, and studied TLR5 stimulation and consecutive NF-κB cascade activation in vitro in two human OPSCC cell lines and immortalized human keratinocytes (HaCat). Clinicopathological data came from hospital registries, and TLR5 immunoexpression was evaluated by immunohistochemistry. Flagellin served to stimulate TLR5 in cultured cells, followed by analysis of the activity of the NF-κB signaling cascade with In-Cell Western for IκΒ and p-IκΒ. High TLR5 expression was associated with poor disease-specific survival in HPV-positive OPSCC, which typically shows low TLR5 immunoexpression. High TLR5 immunoexpression was more common in HPV-negative OPSCC, known for its less-favorable prognosis. In vitro, we detected NF-κΒ cascade activation in the HPV-positive OPSCC cell line and in HaCat cells, but not in the HPV-negative OPSCC cell line. Our results suggest that elevated TLR5 immunoexpression may be related to reduced NF-κΒ activity in HPV-negative OPSCC. The possible prognosis-worsening mechanisms among these high-risk OPSCC patients however, require further evaluation.

PCR-based zebrafish model for personalised medicine in head and neck cancer.

BACKGROUND: Currently, in vivo model for personalised cancer drug testing is challenging. A zebrafish larvae xenograft model has been applied in recent years to cancer research, particularly for drug testing purposes, showing promising results in drug testing against patient-derived tumour xenografts. Currently, these xenograft models apply imaging techniques to measure drug efficacy. However, this method carries several limitations, including timely imaging, thereby reducing the available number of tested fish and drugs. Here, we propose a PCR-based fast assay to evaluate drug efficacy in a zebrafish larvae xenograft model. METHODS: We tested two primary and corresponding metastatic head and neck squamous cell carcinoma (HNSCC) cell lines and patient-derived tongue cancer sample applying zebrafish larvae xenograft model. Cisplatin efficacy was tested using imaging technique and compared the results with PCR-based methods. Drug screening of eight compounds was applied on both cell lines and patient sample using PCR. RESULTS: In a head-to-head comparison, all the three techniques (imaging, quantitative PCR, and droplet digital PCR) showed similar reduction of the cancer cells growth after cisplatin treatment. Using the quantitative PCR assay, we demonstrated a dose-dependent response of HNSCC cells to cisplatin. Drug screening results of four HNSCC cell lines and patient sample revealed different drug efficacy between tested cancer cells. CONCLUSION: We introduce a novel, easy, fast and cost-effective PCR-based in vivo zebrafish larvae assay to test the response of cell lines and clinical tumour samples to anti-cancer drugs. This method goes hand-by-hand with the commonly used imaging assay.

Recurrent transcriptional loss of the PCDH17 tumor suppressor in laryngeal squamous cell carcinoma is partially mediated by aberrant promoter DNA methylation.

Protocadherins are cell-cell adhesion molecules encoded by a large family of genes. Recent reports demonstrate recurrent silencing of protocadherin genes in tumors and provide strong arguments for their tumor supresor functionality. Loss of protocadherins may contribute to cancer development not only by altering cell-cell adhesion, that is a hallmark of cancer, but also by enhancing proliferation and epithelial mesenchymal transition of cells via deregulation of the WNT signaling pathway. In this study we have further corroborated our previous findings on the involvement of PCDH17 in laryngeal squamous cell carcinoma (LSCC). We used bisulfite pyrosequencing to analyze a cohort of primary LSCC tumors for alterations in PCDH17 promoter DNA methylation as an alternative gene inactivation mechanism to the homozygous deletions reported earlier. Moreover, we analyzed primary LSCC samples by immunohistochemistry for PCDH17 protein loss. We identified recurrent elevation of PCDH17 promoter DNA methylation in 32/81 (40%) primary tumors (P < 0.001) and therein hypermethylation of 12 (15%) cases in contrast to no tumor controls (n = 24) that were all unmethylated. Importantly, DNA demethylation by decitabine has restored low level PCDH17 expression in LSCC cell lines. In conclusion, we provide a mechanistic explanation of recurrently observed PCDH17 silencing in LSCC by demonstrating the role of promoter methylation in this process. In light of these findings and recent reports showing that PCDH17 methylation is detectable in serum of cancer patients we suggest that testing PCDH17 DNA methylation might serve as a potential biomarker in LSCC.

Complement Component C3 and Complement Factor B Promote Growth of Cutaneous Squamous Cell Carcinoma.

Cutaneous squamous cell carcinoma (cSCC) is one of the most common metastatic skin cancers with increasing incidence. We examined the roles of complement component C3 and complement factor B (CFB) in the growth of cSCC. Analysis of cSCC cell lines (n = 8) and normal human epidermal keratinocytes (n = 11) with real-time quantitative PCR and Western blotting revealed up-regulation of C3 and CFB expression in cSCC cells. Immunohistochemical staining revealed stronger tumor cell-specific labeling for C3 and CFB in invasive cSCCs (n = 71) and recessive dystrophic epidermolysis bullosa-associated cSCCs (n = 11) than in cSCC in situ (n = 69), actinic keratoses (n = 63), and normal skin (n = 5). Significant up-regulation of C3 and CFB mRNA expression was noted in chemically induced mouse cSCCs, compared to benign papillomas. Knockdown of C3 and CFB expression inhibited migration and proliferation of cSCC cells and resulted in potent inhibition of extracellular signal-regulated kinase 1/2 activation. Knockdown of C3 and CFB markedly inhibited growth of human cSCC xenograft tumors in vivo. These results provide evidence for the roles of C3 and CFB in the development of cSCC and identify them as biomarkers and potential therapeutic targets in this metastatic skin cancer.

Prognostic impact of tumour-stroma ratio in early-stage oral tongue cancers.

AIMS: Oral tongue squamous cell carcinoma (OTSCC) has a relatively poor outcome, and there is a need to identify better prognostic factors. Recently, tumour-stroma ratio (TSR) has been associated with prognosis in several cancers. The aim of this multi-institutional study was to evaluate the prognostic value of TSR from original haematoxylin and eosin (HE)-stained tumour-resection slides in a series of early-stage (cT1-2N0) OTSCC patients. METHODS AND RESULTS: A TSR cutoff value of 50% was used to divide the patients into stroma-rich (≥50%) and stroma-poor (<50%) groups. The relationships between TSR and clinicopathological characteristics of 311 early-stage OTSCC cases were analysed. The prognostic value of TSR in OTSCC was calculated separately and in combination with a previously published cancer cell budding and depth of invasion (BD) prognostic model. A total of 89 cases (28.6%) belonged to the stroma-rich group. In a multivariate analysis, the stroma-rich group had worse disease-free survival, with a hazard ratio (HR) of 1.81 [95% confidence interval (CI) 1.17-2.79, P = 0.008], and higher cancer-related mortality (HR 1.71, 95% CI 1.02-2.86, P = 0.03). The combination of the highest-risk parameter scores of TSR and the BD model showed significant correlations with recurrence rate (HR 3.42, 95% CI 1.71-6.82, P = 0.004) and cancer-related mortality (HR 11.63, 95% CI 3.83-35.31, P < 0.001). CONCLUSIONS: We conclude that TSR is a simple histopathological feature that is useful for prognostication of early-stage OTSCC, and suggest that TSR analyses in association with BD score could be included in routine clinical pathology reports for HE-stained slides.

Liprin-α1 modulates cancer cell signaling by transmembrane protein CD82 in adhesive membrane domains linked to cytoskeleton.

BACKGROUND: PPFIA1 is located at the 11q13 region commonly amplified in cancer. The protein liprin-α1 encoded by PPF1A1 contributes to the adhesive and invasive structures of cytoskeletal elements and is located at the invadosomes in cancer cells. However, the precise mechanism of liprin-α1 function in cancer progression has remained elusive. METHODS: Invasion regulating activity of liprin-α1 was examined by analyzing the functions of squamous cell carcinoma of head and neck (HNSCC) cell lines in three-dimensional collagen I after RNAi mediated gene knockdown. Transcriptome profiling and Gene Set Enrichment Analysis from HNSCC and breast cancer cells were used to identify expression changes relevant to specific cellular localizations, biological processes and signaling pathways after PPFIA1 knockdown. The significance of the results was assessed by relevant statistical methods (Wald and Benjamini-Hochberg). Localization of proteins associated to liprin-α1 was studied by immunofluorescence in 2D and 3D conditions. The association of PPFIA1 amplification to HNSCC patient survival was explored using The Cancer Genome Atlas data. RESULTS: In this study, we show that liprin-α1 regulates biological processes related to membrane microdomains in breast carcinoma, as well as protein trafficking, cell-cell and cell-substrate contacts in HNSCC cell lines cultured in three-dimensional matrix. Importantly, we show that in all these cancer cells liprin-α1 knockdown leads to the upregulation of transmembrane protein CD82, which is a suppressor of metastasis in several solid tumors. CONCLUSIONS: Our results provide novel information regarding the function of liprin-α1 in biological processes essential in cancer progression. The results reveal liprin-α1 as a novel regulator of CD82, linking liprin-α1 to the cancer cell invasion and metastasis pathways.

Outcome of nasopharyngeal carcinoma in Finland: A nationwide study.

BACKGROUND: Nasopharyngeal carcinoma (NPC) is uncommon in western countries and data on the outcome and histological presentation are scarce in nonendemic areas. We report here the outcome on all patients with NPC treated in Finland between 1990 and 2009. MATERIAL AND METHODS: The Finnish Cancer Registry database was used to identify the patients. Histopathological specimens and clinical records were reviewed to confirm the histological subtypes, prognostic factors, treatment techniques and outcome across different stage groups. RESULTS: Primary NPC was identified in 207 patients and 42 (20%) had keratinizing squamous cell carcinoma (SCC). The stage distribution was: I, 11%; II, 25%; III, 39%; IV, 25%. Of 191 patients treated with curative intent 85 (44%) received radiotherapy and 106 (56%) chemoradiotherapy. The five-year overall survival for all patients was 57% and for stages I-IV 87%, 69%, 55% and 31%, respectively. The five-year disease-specific and overall survival of all patients treated between 1990 and 1999 were 58% and 49%, and those between 2000 and 2009 66% and 63%, respectively. CONCLUSIONS: While survival rates are improving and comparable to other western countries they remain inferior to those of endemic countries. This may reflect the different biology of NPC in nonendemic areas, where keratinizing SCC is common.

Epidemiological and treatment-related factors contribute to improved outcome of oropharyngeal squamous cell carcinoma in Finland.

BACKGROUND: Treatment for oropharyngeal squamous cell carcinoma (OPSCC) has changed, as the proportion of human papilloma virus (HPV)-related disease has increased. We evaluated nationwide information on its management and outcome during the treatment paradigm change period. METHODS: We included all patients diagnosed and treated for OPSCC at the five Finnish university hospitals from 2000 to 2009. Patient records and pathology registries provided the clinicopathological data. p16 staining was performed on primary tumor samples of patients who had received treatment with curative intent. RESULTS: A total of 674 patients were diagnosed and treated for OPSCC and the incidence increased along the study period. Of the evaluable tumors 58.5% were p16-positive and the number of p16-positive tumors increased along the years. The treatment was given with curative intent for 600 patients and it was completed in 564. Of them, 47.9% underwent primary surgery and 52.1% received definitive oncological treatment. Also, the treatment protocol changed towards a more oncological approach. Among patients treated with curative intent the five-year overall, disease-specific and disease-free survival rates were 60.1, 71.5 and 57.0%. In multivariate analysis, p16-positivity seemed to relate to reduced disease mortality in lateral and anterior-wall disease. Depending on primary tumor localization, also sex, classes T3-4, presence of regional metastasis and radiotherapy modality had an association with disease mortality. CONCLUSION: The incidence of p16-positive OPSCC and delivery of definitive oncological treatment increased in Finland during the study period. An improved survival outcome compared with the previous nationwide investigation was observed in this subset of patients.

Functional analysis of ESM1 by siRNA knockdown in primary and metastatic head and neck cancer cells.

BACKGROUND: Genetic factors play a large role in cancer, and thus, there is a great desire to understand the effects of different genes in cancer and to also develop gene therapy for better treatments. Therefore, the development of alternative diagnosis and therapy modalities is of utmost importance. The aim of our study was to illuminate the role of ESM1 (endothelial cell-specific molecule-1, also known as Endocan) in proliferation and migration of head and neck cancer, thus helping to pave the way for new treatment modalities and predictive biomarkers. METHODS: ESM1 expression was shown with immunofluorescence assay using confocal laser scanning microscope in primary and metastatic head and neck cancer cells. ESM1 expression was knocked down by RNA interference in head and neck cancer cells. Knockdown efficiency was evaluated by quantitative real-time RT-PCR and Western blot. Cell proliferation and migration assays were performed by xCELLigence real-time cell analysis system. RESULTS: Immunofluorescence assay showed nuclear localization and high expression of ESM1 in primary and metastatic head and neck cancer cells. ESM1 mRNA and protein levels were significantly decreased in ESM1-knockdown cells compared to control. ESM1-knockdown cells showed reduced proliferation and migration activity when compared to control cells. CONCLUSION: These findings suggest that ESM1 has roles on proliferation and migration of head and neck cancer cells.

Recurrent epigenetic silencing of the PTPRD tumor suppressor in laryngeal squamous cell carcinoma.

Cellular processes like differentiation, mitotic cycle, and cell growth are regulated by tyrosine kinases with known oncogenic potential and tyrosine phosphatases that downmodulate the first. Therefore, tyrosine phosphatases are recurrent targets of gene alterations in human carcinomas. We and others suggested recently a tumor suppressor function of the PTPRD tyrosine phosphatase and reported homozygous deletions of the PTPRD locus in laryngeal squamous cell carcinoma. In this study, we investigated other gene-inactivating mechanisms potentially targeting PTPRD, including loss-of-function mutations and also epigenetic alterations like promoter DNA hypermethylation. We sequenced the PTPRD gene in eight laryngeal squamous cell carcinoma cell lines but did not identify any inactivating mutations. In contrast, by bisulfite pyrosequencing of the gene promoter region, we identified significantly higher levels of methylation (p = 0.001 and p = 0.0002, respectively) in 9/14 (64%) laryngeal squamous cell carcinoma cell lines and 37/79 (47%) of primary laryngeal squamous cell carcinoma tumors as compared to normal epithelium of the upper aerodigestive tract. There was also a strong correlation (p = 0.0001) between methylation and transcriptional silencing for the PTPRD gene observed in a cohort of 497 head and neck tumors from The Cancer Genome Atlas dataset suggesting that DNA methylation is the main mechanism of PTPRD silencing in these tumors. In summary, our data provide further evidence of the high incidence of PTPRD inactivation in laryngeal squamous cell carcinoma. We suggest that deletions and loss-of-function mutations are responsible for PTPRD loss only in a fraction of cases, whereas DNA methylation is the dominating mechanism of PTPRD inactivation.

Prognostic significance of the methylation of Wnt pathway antagonists-CXXC4, DACT2, and the inhibitors of sonic hedgehog signaling-ZIC1, ZIC4, and HHIP in head and neck squamous cell carcinomas.

OBJECTIVES: Aberrations in Wnt and Shh signaling pathways are related to the pathogenesis of head and neck carcinomas, and their activation frequently results from epigenetic alterations. This study aimed to assess the frequency of methylation of negative regulators of Wnt signaling: CXXC4, DACT2, HDPR1, and FBXW11 and Shh signaling: HHIP, PTCH1, SUFU, ZIC1, and ZIC4 and correlate it with clinicopathological features in this group of patients. MATERIALS AND METHODS: Methylation-specific PCR was used to detect gene promoter methylation, and real-time PCR was used to assess gene expression level. RESULTS: The analysis of the occurrence of gene promoter methylation in head and neck carcinoma cell lines indicated that CXXC4, DACT2, HHIP, ZIC1, and ZIC4 are methylated in these tumors. These genes were further analyzed in tumor sections from oral and laryngeal cancer patients. Gene methylation rate was higher in laryngeal tumors. The methylation index in tumor samples correlated with the overall survival in a subgroup of oral cancer patients who died of the disease. Moreover, ZIC4 methylation correlated with lymph node involvement in oral cancer patients. CONCLUSIONS: Our findings corroborate that the activation of Wnt signaling in head and neck squamous cell carcinoma (HNSCC) is related to epigenetic silencing of its negative regulators. Moreover, the results indicate that the same mechanism of activation may operate in the case of Shh signaling. CLINICAL RELEVANCE: The methylation of ZIC4 may be considered a new prognostic marker in oral cavity and oropharyngeal tumors. Further investigations should determine the diagnostic significance of methylation of ZIC4, HHIP, and DACT2 in head and neck carcinomas.

Ecto-5'-nucleotidase/CD73 enhances endothelial barrier function and sprouting in blood but not lymphatic vasculature.

CD73/ecto-5'-nucleotidase is a key enzyme in the regulation of purinergic signaling and inflammatory reactions. It hydrolyzes extracellular AMP into adenosine, which dampens immune cell activation, and reduces leukocyte trafficking. By comparing CD73 expression and function in mononuclear and endothelial cells (ECs) of blood and lymph, we show that extracellular purines and CD73 activity have differential effects in these two vascular systems. We found that CD8-positive T lymphocytes and CD19-positive B lymphocytes in human lymph expressed high levels of CD73 and other purinergic enzymes and adenosine receptors. Soluble CD73 was less abundant in human lymph than in serum, whereas CD73 activity was higher in afferent lymphatic ECs than in blood ECs. Adenosine signaling improved barrier function and induced sprouting of human blood, but not lymphatic, ECs in vitro. Similarly, using CD73-deficient mice we found that CD73 controls only blood vascular permeability at selected lymphoid organs under physiological conditions. Thus, both vascular and lymphatic arms of the immune system synthesize the components of purinergic signaling system, but surprisingly they use CD73 differentially to control endothelial permeability and sprouting.

Proteomic profiling identifies the inorganic pyrophosphatase (PPA1) protein as a potential biomarker of metastasis in laryngeal squamous cell carcinoma.

Relapse and metastasis are the main causes of unfavorable outcome in head and neck cancers. Whereas, understanding of the molecular background of these processes is far from being complete. Therefore, in this study we aimed to identify potential biomarker candidates of relapse and metastasis in laryngeal squamous cell carcinoma (LSCC) by combining the 2D electrophoresis based protein screen and immunohistochemical analysis of candidate proteins. We screened three groups of LSCC cell lines derived from primary tumors, recurrent tumors and metastases and identified seven proteins that differed significantly in relative abundance between the analyzed groups. Among the identified proteins were the heat shock proteins HSP60 and HSP70 that were significantly downregulated both in recurrences- and metastases-derived cell lines but not in primary tumor-derived cell lines. Moreover, we identified significant upregulation of the annexin V, calreticulin and the inorganic pyrophosphatase (PPA1) exclusively in the metastases-derived cell lines. As these upregulated proteins could potentially become novel biomarkers of metastasis, we have compared their abundance in primary tumor LSCC N(0) cases, primary tumor LSCC N(+) cases as well as in LSCC metastases N(+). Our results show an intense increase of cytoplasmic PPA1 abundance in the N(+) (p = 0.000042) compared to the N(0) group. In summary, we show a group of proteins deregulated in recurrences and metastases of LSCC. Moreover, we suggest the PPA1 protein as a potential new biomarker for metastasis in this cancer.

Copy number increase of oncoprotein CIP2A is associated with poor patient survival in human head and neck squamous cell carcinoma.

BACKGROUND: CIP2A, an inhibitor of PP2A tumour suppressor function, is a widely overexpressed biomarker of aggressive disease and poor therapy response in multiple human cancer types. METHODS: CIP2A and DPPA4 copy number alterations and expression were analysed by fluorescence in situ hybridisation (FISH) and immunohistochemistry (IHC) in different cell lines and a tissue microarray of 52 HNSCC patients. Results were correlated with patient survival and other clinicopathological data. RESULTS: CIP2A and DPPA4 copy number increase occurred at a relatively high frequency in human HNSCC patient samples. CIP2A but not DPPA4 FISH status was significantly associated with patient survival. CIP2A detection by combining IHC with FISH yielded superior resolution in the prognostication of HNSCC. CONCLUSIONS: CIP2A copy number increase is associated with poor patient survival in human HNSCC. We suggest that the reliability and prognostic value of CIP2A detection can be improved by performing FISH analysis to CIP2A IHC positive tumours.

Investigation of the expression of RIF1 gene on head and neck, pancreatic and brain cancer and cancer stem cells.

PURPOSE: Recent studies have shown that cancer stem cells are resistant to chemotherapy. The aim of this study was to compare RIF1 gene expression in head and neck, pancreatic cancer and glioma cell lines and the cancer stem cells isolated from these cell lines. METHODS: UT-SCC-74 from Turku University and UT-SCC-74B primary tumor metastasis and neck cancer cell lines, YKG-1 glioma cancer cell line from RIKEN, pancreatic cancer cell lines and ASPC-1 cells from ATCC were grown in cell culture. To isolate cancer stem cells, ALDH-1 for UT-SCC-74 and UT-SCC-74B cell line, CD-133 for YKG-1 cell line and CD-24 for ASPC-1 cell line, were used as markers of cancer stem cells. RNA isolation was performed for both cancer lines and cancer stem cells. RNAs were converted to cDNA. RIF1 gene expression was performed by qRT-PCR analysis. RIF1 gene expression was compared with cancer cell lines and cancer stem cells isolated from these cell lines. The possible effect of RIF1 gene was evaluated. RESULTS: In the pancreatic cells, RIF1 gene expression in the stem cell-positive cell line was 256 time that seen in the stem cell-negative cell line. CONCLUSION: Considering the importance of RIF1 in NHEJ and of NHEJ in pancreatic cancer, RIF1 may be one of the genes that plays an important role in the diagnoses and therapeutic treatment of pancreatic cancer. The results of head and neck and brain cancers are inconclusive and further studies are required to elucidate the connection between RIF1 gene and these other types of cancers.

The negative regulators of Wnt pathway-DACH1, DKK1, and WIF1 are methylated in oral and oropharyngeal cancer and WIF1 methylation predicts shorter survival.

The deregulation of Wnt signaling has recently emerged as one of the drivers of head and neck cancers. This is frequently related to the methylation of several antagonists of this pathway. This study aimed at the assessment of the profile of methylation of Wnt pathway antagonists and the determination of the prognostic value of the methylation of selected genes in oral carcinomas. The methylation of DACH1, DKK1, LKB1, PPP2R2B, RUNX3, SFRP2, and WIF-1 was analyzed in 16 oral squamous cell carcinoma cell lines using the methylation-specific polymerase chain reaction. The methylation of selected genes was further analyzed in tumor sections from 43 primary oral carcinoma patients. The analysis of oral carcinoma cell lines showed very frequent methylation of SFRP2 and WIF-1 and also a less frequent methylation of DACH1 and DKK1. On the other hand, RUNX3 was methylated only in one cell line, while LKB1 and PPP2R2B were not methylated in any of the cell lines. The biallelic methylation of DKK1 correlated with the low level of expression of this gene. Further evaluation of the methylation of DACH1, DKK1, and WIF1 in a clinical patient group confirmed the frequent methylation of WIF1 and intermediate or low frequency of methylation of DACH1 or DKK1, respectively. Importantly, the methylation of WIF-1 correlated with shorter survival in oral cancer patients. Overall, the methylation of the antagonists of Wnt pathway is frequently detected in oral squamous cell carcinomas. The methylation of WIF1 may be considered a prognostic marker in oral cancers.