DEK Oncogene Research Articles

IMMUNOEXPRESSION OF DEK AND PHOSPHO-P38 PROTEINS IN RECTAL CANCER BEFORE CHEMORADIATION THERAPY.

Colorectal cancer is the third cause of cancer worldwide and a quarter of them are in the rectum. DEK oncogene is involved in several nuclear processes and can accelerate tumorigenesis. This study aims to evaluate the immunoexpression of DEK and Phospho-P38 proteins before neoadjuvant therapy in patients with rectum adenocarcinoma and correlate it with a clinical response and survival. Patients with adenocarcinoma of the middle and low rectum who underwent chemotherapy and radiotherapy followed by surgical tumor resection were included. The expression and quantification were studied by immunohistochemistry in the tumor biopsy tissues using a HScore system. Score ≥4 were considered positive and those with <4 negative. 22 patients were included with a mean age of 63.55 years (SD: ±13.49). The clinical-stage before treatment was T3 on 72.7%, T4 on 18.2%, 31.8% were N1, 50% N0 and all M0. After chemo and radiotherapy, 54.6% were T3; 22.7% were classified as T2; 9.1% as T1, and 13.6% were T0. Among the tumors, 22.7% were positive for DEK and 63.6% positive for Phospho-P38. There was a positive correlation between DEK protein before treatment and pTNM stage (P=0.011). Phospho-P38 protein showed no correlation with these parameters. Patients with a negative HScore had a mean survival of 141.33 months (95%CI: 112.41-170.25) and those with a positive HSscore had a mean survival of 25.10 months (95%CI: 17.36-32.84; P<0.001). A higher expression of DEK was observed in advanced stages. Patients who presented DEK expression <4 had a higher survival, being a factor of worst prognosis.

MiR-138-5p Inhibits the Proliferation of Gastric Cancer Cells by Targeting DEK.

BackgroundIncreasing evidence suggests that microRNAs (miRNAs) play critical roles in cancer progression. Therefore, investigating the function of miRNAs that are aberrantly expressed in gastric cancer (GC) and characterizing the involved underlying mechanism are essential for the treatment of gastric cancer. MiR-138-5p was found to be down-regulated in multiple cancers, which acted as a tumor suppressor in cancer progression; however, whether and how miR-138-5p regulates the malignant behaviors of GC has not been fully understood.MethodsThe level of miR-138-5p in GC tissues and cell lines was detected by RT-qPCR. The effects of miR-138-5p on the growth of GC cells were evaluated by the in vitro Cell Counting Kit-8 (CCK-8) assay, cell apoptosis, cell cycle analysis, wound-healing assay, and in vivo xenograft mice model. The targets of miR-138-5p were predicted using the miRDB online tool, confirmed by luciferase report assay and Western blot.ResultsMiR-138-5p was frequently decreased in GC tissues and cell lines. Decreased expression of miR-138-5p was significantly associated with the lymph node metastasis of GC patients. Overexpression of miR-138-5p suppressed GC cell proliferation, migration, increased cell apoptosis as well as inhibited the tumor growth in vivo. DEK oncogene was predicted as a potential target of miR-138-5p. MiR-138-5p bound the 3ʹ-UTR of DEK and inhibited the level of DEK in GC cells. Restoration of DEK abrogated miR-138-5p overexpression-mediated suppression of GC cell proliferation and cell cycle arrest.ConclusionOur results demonstrated the anti-cancer role of miR-138-5p in GC by targeting DEK, which suggested miR-138-5p as a potential therapeutic target for the treatment of patient with GC.

Abstract 2836: Expression of the DEK oncogene in breast cancer cells promotes M2 polarization of tumor associated macrophages

Abstract Breast cancer is the second leading cause of cancer deaths among women. DEK is a known oncoprotein found to be highly expressed in more than 60% breast cancers and is found to be an independent marker of poor prognosis. However, the molecular mechanisms by which DEK promotes tumor progression are poorly understood. To elucidate the oncogenic functions of DEK, we performed RNA-seq analysis on isogenic Dek-knockout and complemented murine breast cancer cells, which indicated dysregulation of immune signaling. Among the target genes identified and confirmed was an upregulation of thymic stromal lymphopoietin (TSLP) in Dek expressing murine breast cancer cells. TSLP was previously shown by Han et al to amplify the alternative (M2) activation of macrophages. M2-like macrophages are tumor promoting, they recycle iron for cell growth and encourage tissue remodeling and repair activities like angiogenesis. To test the immune modulating functions of Dek-expressing breast cancer cells, we treated bone marrow derived macrophages (BMDM) with tumor cell conditioned media. We found that in vitro, Dek expressing cancer cells induced an M2-like polarization of macrophages, as determined by the expression of M2-associated genes, enhanced migration, and iron recycling phenotypes, which was accompanied by inhibited ERK1/2 signaling. We found this phenotypic trend to be true in vivo, as well. In sectioned mammary tumors from MMTV-RontgDek+/+ and MMTV-RontgDek−/− mice, we see lower levels of iron staining in Dek+/+ tumors than in Dek−/− tumors using Prussian blue staining that co-localized with F4/80 macrophage marker staining. This suggested that Dek expression in the tumors induced an iron recycling, M2-like phenotype in tumor associated macrophages. Furthermore, we observed increased TSLP expression and angiogenesis, as determined by CD31 staining, in Dek-expressing tumors in vivo. These findings suggest that tumor Dek expression may promote breast cancer progression by inducing M2-like macrophage polarization in a murine breast cancer model. Citation Format: Miranda Shephard, Nicholas Pease, Lisa M. Privette Vinnedge. Expression of the DEK oncogene in breast cancer cells promotes M2 polarization of tumor associated macrophages [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2836.

The miR-1204 regulates apoptosis in NSCLC cells by targeting DEK.

This study endeavors to analyze the effects of miR-1204 on the expression of DEK oncogene in non-small cell lung cancer (NSCLC) cell lines and to study the molecular mechanisms of these effects. The miR-1204 mimics and inhibitors were transfected into the (A549 and SPC) NSCLC cells. Then the mRNA levels, cell viability, apoptosis rate, morphology and caspase activity were determined. The expression of apoptosis-related proteins Bcl-2 and Bax was also analyzed. In NSCLC cell lines (A549 and SPC), DEK mRNA levels were down-regulated in miR-1204 overex-pression group. In miR-1204 inhibition group, the expression of DEK mRNA showed an opposite trend. The overexpression of miR-1204 increases the apoptosis rate in NSCLC cells. The Bcl-2 levels in the miR-1204 over-expression group were decreased, while the Bax level was increased. In the miR-1204 inhibition group, expression of Bcl-2 and Bax showed opposite trends. Cell staining revealed cell's morphological changes; the apoptosis in the miR-1204 overexpression group revealed significant morphological features, such as brighter nuclei and nu-clear condensation. Results indicated a typical characteristic of apoptosis in the miR-1204 overexpression group. Caspase-9 and Caspase-3 were involved in the apoptosis pathway, which was mediated by miR-1204 and DEK. The miR-1204 induces apoptosis of NSCLC cells by inhibiting the expression of DEK. The mech-anism of apoptosis involves down-regulation of Bcl-2 and up-regulation of Bax expression. Moreover, the apoptosis was mediated by mitochondria-related caspase 9/3 pathway.

Optical Redox Imaging Detects the Effects of DEK Oncogene Knockdown on the Redox State of MDA-MB-231 Breast Cancer Cells.

Optical redox imaging (ORI), based on collecting the endogenous fluorescence of reduced nicotinamide adenine dinucleotide (NADH) and oxidized flavoproteins (Fp) containing a redox cofactor flavin adenine dinucleotide (FAD), provides sensitive indicators of cellular metabolism and redox status. ORI indices (such as NADH, FAD, and their ratio) have been under investigation as potential progression/prognosis biomarkers for cancer. Higher FAD redox ratio (i.e., FAD/(FAD + NADH)) has been associated with higher invasive/metastatic potential in tumor xenografts and cultured cells. This study is to examine whether ORI indices can respond to the modulation of oncogene DEK activities that change cancer cell invasive/metastatic potential. Using lentiviral shRNA, DEK gene expression was efficiently knocked down in MDA-MB-231 breast cancer cells (DEKsh). These DEKsh cells, along with scrambled shRNA-transduced control cells (NTsh), were imaged with a fluorescence microscope. In vitro invasive potential of the DEKsh cells and NTsh cells was also measured in parallel using the transwell assay. FAD and FAD redox ratios in polyclonal cells with DEKsh were significantly lower than that in NTsh control cells. Consistently, the DEKsh cells demonstrated decreased invasive potential than their non-knockdown counterparts NTsh cells. This study provides direct evidence that oncogene activities could mediate ORI-detected cellular redox state.

Abstract 3471: Expression of the DEK oncogene in breast cancer cells promotes M2 polarization of tumor associated macrophages

Abstract Breast cancer is the most common cancer and the second leading cause of cancer deaths among women. DEK is a known oncoprotein found to be highly expressed in more than 60% breast cancers and is found to be an independent marker of poor prognosis. However, the molecular mechanisms by which DEK promotes tumor progression are poorly understood. To elucidate the oncogenic functions of DEK, we performed RNA-seq analysis on isogenic Dek-knockout and complemented murine breast cancer cells, which indicated dysregulation of immune signaling. Among the target genes identified and confirmed was an upregulation of thymic stromal lymphopoietin (TSLP) in Dek expressing breast cancer cells. TSLP was previously shown by Han et al to amplify the alternative (M2) activation of macrophages. M2-like macrophages are tumor promoting, they recycle iron for cell growth and encourage tissue remodeling and repair activities like angiogenesis. Classically (M1) activated macrophages are tumor suppressing and are typically associated with response to infection. To test the immune modulating functions of Dek-expressing breast cancer cells, we treated bone marrow derived macrophages (BMDM) with tumor cell conditioned media. We found that in vitro, Dek expressing cancer cells induced an M2-like polarization of macrophages, as determined by the expression of M2-associated genes, enhanced migration, and iron recycling phenotypes, which was accompanied by inhibited ERK1/2 sighnaling. We found this phenotypic trend to be true in vivo, as well. In sectioned mammary tumors from MMTV-RontgDek+/+ and MMTV-RontgDek-/- mice, we see lower levels of iron staining in Dek+/+ tumors than in Dek-/- tumors using Prussian blue staining that co-localized with F4/80 macrophage marker staining. This suggested that Dek expression in the tumors induced an iron recycling, M2-like phenotype in tumor associated macrophages. These findings suggest that tumor Dek expression may promote breast cancer progression by inducing M2-like macrophage polarization in a murine breast cancer model. Citation Format: Miranda S. Shephard, Nicholas A. Pease, Jon Cheek, Lisa M. Privette Vinnedge. Expression of the DEK oncogene in breast cancer cells promotes M2 polarization of tumor associated macrophages [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3471.

Dek overexpression in murine epithelia increases overt esophageal squamous cell carcinoma incidence.

Esophageal cancer occurs as either squamous cell carcinoma (ESCC) or adenocarcinoma. ESCCs comprise almost 90% of cases worldwide, and recur with a less than 15% five-year survival rate despite available treatments. The identification of new ESCC drivers and therapeutic targets is critical for improving outcomes. Here we report that expression of the human DEK oncogene is strongly upregulated in esophageal SCC based on data in the cancer genome atlas (TCGA). DEK is a chromatin-associated protein with important roles in several nuclear processes including gene transcription, epigenetics, and DNA repair. Our previous data have utilized a murine knockout model to demonstrate that Dek expression is required for oral and esophageal SCC growth. Also, DEK overexpression in human keratinocytes, the cell of origin for SCC, was sufficient to cause hyperplasia in 3D organotypic raft cultures that mimic human skin, thus linking high DEK expression in keratinocytes to oncogenic phenotypes. However, the role of DEK over-expression in ESCC development remains unknown in human cells or genetic mouse models. To define the consequences of Dek overexpression in vivo, we generated and validated a tetracycline responsive Dek transgenic mouse model referred to as Bi-L-Dek. Dek overexpression was induced in the basal keratinocytes of stratified squamous epithelium by crossing Bi-L-Dek mice to keratin 5 tetracycline transactivator (K5-tTA) mice. Conditional transgene expression was validated in the resulting Bi-L-Dek_K5-tTA mice and was suppressed with doxycycline treatment in the tetracycline-off system. The mice were subjected to an established HNSCC and esophageal carcinogenesis protocol using the chemical carcinogen 4-nitroquinoline 1-oxide (4NQO). Dek overexpression stimulated gross esophageal tumor development, when compared to doxycycline treated control mice. Furthermore, high Dek expression caused a trend toward esophageal hyperplasia in 4NQO treated mice. Taken together, these data demonstrate that Dek overexpression in the cell of origin for SCC is sufficient to promote esophageal SCC development in vivo.

Decreased plasma DEK Oncogene Levels Correlate with p16-Negative Disease and Advanced Tumor Stage in a Case–Control Study of Patients with Head and Neck Squamous Cell Carcinoma

Head and neck cancer (HNC) remains the sixth most common malignancy worldwide and survival upon recurrence and/or metastasis remains poor. HNSCC has traditionally been associated with alcohol and nicotine use, but more recently the Human Papilloma Virus (HPV) has emerged as a favorable prognostic risk factor for oropharyngeal HNSCC. However, further stratification with additional biomarkers to predict patient outcome continues to be essential. One candidate biomarker is the DEK oncogenic protein, which was previously detected in the urine of patients with bladder cancer and is known to be secreted by immune cells such as macrophages. Here, we investigated if DEK could be detected in human plasma and if DEK levels correlated with clinical and pathological variables of HNSCC. Plasma was separated from the peripheral blood of newly diagnosed, untreated HNSCC patients or age-matched normal healthy controls and analyzed for DEK protein using ELISA. Plasma concentrations of DEK protein were lower in p16-negative tumors compared to both normal controls and patients with p16-positive tumors. Patients with lower plasma concentrations of DEK were also more likely to have late stage tumors and a lower white blood cell count. Contrary to previously published work demonstrating a poor prognosis with high intratumoral DEK levels, we show for the first time that decreased concentrations of DEK in patient plasma correlates with poor prognostic factors, including HPV-negative status as determined by negative p16 expression and advanced tumor stage.

Abstract 50: Plasma concentrations of the DEK oncogene correlate with pathological variables in a case-control study of patients with HNSCC

Abstract Background: Head and neck squamous cell carcinoma (HNSCC) has traditionally been associated with alcohol and nicotine use, but more recently the Human Papilloma Virus (HPV) has emerged as a favorable prognostic risk factor for oropharyngeal HNSCC. However, further stratification with additional biomarkers to predict patient outcome continues to be essential. One candidate biomarker is the chromatin remodeling DEK protein, which is both an auto-antigen in autoimmune diseases and an oncogene in epithelial tissues. DEK is secreted by stimulated macrophages and neutrophils and was previously detected in the urine of patients with bladder cancer. Previously, we have reported that DEK mRNA and protein is upregulated in HNC tumor tissue and higher DEK levels are associated with poor prognoses in many types of solid tumors. We hypothesized that DEK could be detected in the plasma of HNC patients, either due to secretion from the tumor or as part of the antitumor immune response, and therefore may be a biomarker for disease status. Methods: We recruited 38 newly diagnosed HNSCC patients and 37 age-matched normal healthy controls into the study. Plasma isolated from peripheral blood was subjected to DEK specific ELISA and DEK concentration levels were compared to levels found in normal controls, and to clinical and pathological variables. Results: We show for the first time that DEK can be detected in human plasma. We did not find an association between DEK plasma concentrations and variables including sex, age, race, or drinking/smoking status. However, we detected decreased concentrations of DEK in HNC patients with p16-negative disease and in patients with larger tumor sizes, indicating an association between DEK levels and known prognostic markers. In addition, HNC patients with lower DEK concentrations had a decreased white blood cell count, largely due to differences in lymphocyte and eosinophil counts. This direct association between plasma DEK levels and white blood cell count was independent of p16 status. Conclusions: Together, the data suggest that lower levels of DEK in HNC patient plasma may be predictive of poor outcome. This is in direct contrast to what is observed with intratumoral levels of DEK protein, in which higher levels of DEK expression are an independent factor predicting poor prognosis. Future studies will investigate the role that secreted DEK, such as that found in the plasma, may have in the antitumor immune response. Citation Format: Trisha Wise-Draper, Arun Sendilnathan, Sarah Palackdharry, Nicholas Pease, Julianne Qualtieri, Randy Butler, Nooshin Hashemi Sadraei, John C. Morris, Yash Patil, Keith Wilson, Jonathan Mark, Keith Casper, Vinita Takiar, Adam Lane, Lisa M. Privette Vinnedge. Plasma concentrations of the DEK oncogene correlate with pathological variables in a case-control study of patients with HNSCC [abstract]. In: Proceedings of the AACR-AHNS Head and Neck Cancer Conference: Optimizing Survival and Quality of Life through Basic, Clinical, and Translational Research; April 23-25, 2017; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2017;23(23_Suppl):Abstract nr 50.

Overexpression of the human DEK oncogene reprograms cellular metabolism and promotes glycolysis.

The DEK oncogene is overexpressed in many human malignancies including at early tumor stages. Our reported in vitro and in vivo models of squamous cell carcinoma have demonstrated that DEK contributes functionally to cellular and tumor survival and to proliferation. However, the underlying molecular mechanisms remain poorly understood. Based on recent RNA sequencing experiments, DEK expression was necessary for the transcription of several metabolic enzymes involved in anabolic pathways. This identified a possible mechanism whereby DEK may drive cellular metabolism to enable cell proliferation. Functional metabolic Seahorse analysis demonstrated increased baseline and maximum extracellular acidification rates, a readout of glycolysis, in DEK-overexpressing keratinocytes and squamous cell carcinoma cells. DEK overexpression also increased the maximum rate of oxygen consumption and therefore increased the potential for oxidative phosphorylation (OxPhos). To detect small metabolites that participate in glycolysis and the tricarboxylic acid cycle (TCA) that supplies substrate for OxPhos, we carried out NMR-based metabolomics studies. We found that high levels of DEK significantly reprogrammed cellular metabolism and altered the abundances of amino acids, TCA cycle intermediates and the glycolytic end products lactate, alanine and NAD+. Taken together, these data support a scenario whereby overexpression of the human DEK oncogene reprograms keratinocyte metabolism to fulfill energy and macromolecule demands required to enable and sustain cancer cell growth.

DEK protein level is a biomarker of CD138positive normal and malignant plasma cells.

Overexpression of DEK oncogene is associated with increased proliferation of carcinoma cells and it is observed in several solid tumors due to the amplification of the 6p22.3 chromosomal region where DEK locates. Although the same chromosomal amplification occurs in multiple myeloma (MM), a plasma cell neoplasm, whether the expression and the copy number of the DEK gene are affected in MM remains elusive. We show that despite the increased copy number in CD138positive MM cells (4 out of 41 MM samples), DEK mRNA expression was down-regulated compared with that in CD138negative bone marrow (BM) cells of the same patients (P<0.0001). DEK protein was not detectable by immunohistochemistry (IHC) in CD138positive normal plasma cells or in malignant plasma cells of MM patients (n = 56) whereas it was widely expressed in normal and neoplastic B-cells. Stable knockdown or overexpression of DEK in CD138positive MM cell lines did not affect the proliferation and viability of the cells profoundly in the presence or absence of chemotherapeutic agent melphalan whereas knockdown of DEK moderately but significantly increased the expression level of CD138 (p<0.01). Decreased DEK expression in plasma cells suggests a potential role of this gene in plasma cell development and lack of detectable DEK protein by IHC could be used as a biomarker for normal and malignant plasma cells.

Abstract S4-05: Expression of the DEK oncogene promotes M2 polarization and iron recycling in tumor associated macrophages

Abstract The chromatin-remodeling DEK oncogene is highly expressed in over 60% of breast cancers, regardless of sub-type. DEK over-expression correlates with poor clinical outcome, including decreased survival and chemotherapy resistance. Previously, using human breast cancer cell lines and the MMTV-Ron mouse breast cancer model, we have demonstrated that DEK expression promotes proliferation and metastasis and supports the breast cancer stem cell population. These functions were due, in part, through upregulated Wnt ligand expression and β-catenin activation, leading to paracrine and autocrine effects promoting tumorigenesis. To investigate additional drivers of DEK-induced tumorigenesis, we performed RNA-Sequencing on control and DEK over-expressing immortalized MCF10A cells. Gene ontology analysis identified several immune signaling processes. This is in alignment with the well-characterized role of DEK expression in the promotion of inflammatory diseases. We investigated the immune cell infiltration of tumors from MMTV-Ron/Dek+/+ and MMTV-Ron/Dek-/- mice. Interestingly, we discovered that Dek-expressing tumors demonstrated decreased tumor associated macrophage (TAM) infiltration, where TAMs were largely limited to the periphery. Furthermore, these TAMs demonstrated an iron-recycling phenotype (M2 polarization), whereas TAMs from Dek-knockout tumors retained iron (M1 polarization). M1 macrophages are typically associated with inflammatory responses whereas M2 macrophages have been linked to tissue remodeling, angiogenesis, and tumor promotion. To investigate this further, we compared Dek+/+ and Dek-/- bone marrow-derived macrophages (BMDM) and found no inherent difference in polarization. However, BMDM demonstrated different gene expression profiles when cultured in conditioned media from Dek-expressing murine breast cancer cell lines compared to isogenic Dek-/- cells. BMDM exposed to conditioned media from Dek-expressing cancer cells demonstrated the same iron recycling phenotype observed in vivo, likely caused by increased expression of ferroportin, as well as increased expression of M2 markers CXCR4, VEGF, and an elevated ARG1hi/NOSlo population. We thus used a combination of genetic models and small molecule inhibitors to identify the mechanism of M2 polarization of BMDM exposed to Dek-expressing cancer cells. NRF2 transcription activity was eliminated as a possible mechanism for ferroportin regulation. However, small molecule inhibitors and gene expression analyses implicated secreted Wnt ligands and S100A8/A9 alarmins from the cancer cells, and downstream C/EBP transcriptional activity in the macrophages, as possible mechanisms of Dek-induced M2 polarization. Combined, this suggests that the poor clinical outcome of high DEK expressing breast cancers may be due to not only cell intrinsic factors, but also cell extrinsic factors, such as the tumor-promoting M2 polarization of tumor associated macrophages. Citation Format: Privette Vinnedge LM, Pease NA, Cheek J. Expression of the DEK oncogene promotes M2 polarization and iron recycling in tumor associated macrophages [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr S4-05.

The DEK oncogene activates VEGF expression and promotes tumor angiogenesis and growth in HIF-1α-dependent and -independent manners.

The DEK oncogene is overexpressed in various cancers and overexpression of DEK correlates with poor clinical outcome. Vascular endothelial growth factor (VEGF) is the most important regulator of tumor angiogenesis, a process essential for tumor growth and metastasis. However, whether DEK enhances tumor angiogenesis remains unclear. Here, we show that DEK is a key regulator of VEGF expression and tumor angiogenesis. Using chromatin immunoprecipitation assay, we found that DEK promoted VEGF transcription in breast cancer cells (MCF7, ZR75-1 and MDA-MB-231) by directly binding to putative DEK-responsive element (DRE) of the VEGF promoter and indirectly binding to hypoxia response element (HRE) upstream of the DRE through its interaction with the transcription factor hypoxia-inducible factor 1α (HIF-1α), a master regulator of tumor angiogenesis and growth. DEK is responsible for recruitment of HIF-1α and the histone acetyltransferase p300 to the VEGF promoter. DEK-enhanced VEGF increases vascular endothelial cell proliferation, migration and tube formation as well as angiogenesis in the chick chorioallantoic membrane. DEK promotes tumor angiogenesis and growth in nude mice in HIF-1α-dependent and -independent manners. Immunohistochemical staining showed that DEK expression positively correlates with the expression of VEGF and microvessel number in 58 breast cancer patients. Our data establish DEK as a sequence-specific binding transcription factor, a novel coactivator for HIF-1α in regulation of VEGF transcription and a novel promoter of angiogenesis.

The DEK Oncogene Can Be Detected in the Plasma of Head and Neck Cancer Patients and May Be Correlated With Tumor Immune Response and Prognosis

The DEK Oncogene Can Be Detected in the Plasma of Head and Neck Cancer Patients and May Be Correlated With Tumor Immune Response and Prognosis

Abstract A51: Investigation of the DEK oncogene as a blood biomarker for breast cancer

Abstract Breast cancer (BC) is one of the leading causes of death for women in the United States. This is due, in part, because women wait too long to get a diagnosis or the disease returns, sometimes years later, due to ineffective treatment. Therefore, it is critically important to identify biomarkers that can better inform clinicians while providing a screening test more amenable to patients than mammograms. We are investigating the feasibility of using DEK protein levels in patient plasma as a biomarker for disease stage and prognosis. DEK is a chromatin-organizing protein that functions in DNA replication and repair, transcription, and mRNA splicing. The DEK oncoprotein is highly upregulated in many types of cancer including breast, head and neck, and melanoma. Using human cell culture and murine models, our previous studies have shown that DEK is functionally important for the promotion of cellular growth, invasion/metastasis, drug resistance, and breast cancer stem cell maintenance. Work by the Markovitz laboratory indicated that DEK is secreted by macrophages as a pro-inflammatory signaling molecule and can be internalized by neighboring cancer cells to promote typical DEK functions. This led to our hypothesis that DEK may be present in the plasma of cancer patients. In fact, the detection of DEK protein in urine is currently being explored as a diagnostic biomarker for bladder cancer. To test this hypothesis, we collected peripheral blood from patients with newly diagnosed, untreated BC (irrespective of the clinical stage) and age- and ethnicity-matched normal healthy controls. Plasma was separated from the samples and subjected to DEK specific ELISA (Cusabio, Wuhan, China). Preliminary results demonstrate that DEK is indeed present in the plasma of BC patients and we are currently comparing these levels to normal healthy controls. Further analyses are ongoing to determine whether DEK levels correlate with pertinent clinical and pathological variables including age, tumor stage, and ER/PR/HER-2 status. In addition, we are examining if DEK levels can predict response to various treatment modalities and risk of relapse. These data will be important to verify DEK plasma measurements as a clinically useful test and may give insight to future personalized and targeted treatment strategies for BC. Citation Format: Arun Sendilnathan, Mahmoud Charif, Elizabeth Shaughnessy, Jaime D. Lewis, Neetu Radhakrishnan, Elyse Lower, Catherine Lanigan, Harriet Kumar, Trisha M. Wise-Draper, Lisa Privette Vinnedge. Investigation of the DEK oncogene as a blood biomarker for breast cancer. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Breast Cancer Research; Oct 17-20, 2015; Bellevue, WA. Philadelphia (PA): AACR; Mol Cancer Res 2016;14(2_Suppl):Abstract nr A51.

Abstract 584: The DEK oncogene may serve as a predictive plasma biomarker in head and neck cancer patients

Abstract Head and neck cancer (HNC) remains the sixth most common cancer worldwide with almost 50,000 new diagnoses in the US each year. Although, infection with HPV has emerged as a favorable prognostic factor for head and neck squamous cell carcinoma (HNSCC) leading to de-intensifying treatment strategies, no serum biomarkers currently exist to predict tumor response and/or relapse. One candidate serum biomarker is encoded by the human DEK gene. DEK mRNA and protein is highly upregulated in tissue specimens from several tumor types including HNSCC, breast cancer and melanoma and antibodies to DEK are detected in patients with auto-immune disease (juvenile rheumatoid arthritis, systemic lupus erythematous, etc.). Our previous work has demonstrated that DEK is highly and universally expressed in HNSCC tissue specimens regardless of stage or HPV infection. Additionally, in vitro data has suggested that tumor associated macrophages secrete DEK protein leading to the hypothesis that DEK may be present in the serum of cancer patients. In fact, the detection of DEK protein in urine is currently being explored as a diagnostic biomarker for bladder cancer. Here, we sought to determine if secreted DEK protein can be detected in human plasma and if it could be used as a biomarker for HNSCC. Peripheral blood was collected from either patients with newly diagnosed, untreated, HNSCC or age-matched normal healthy controls. Plasma was separated from the samples and subjected to DEK specific ELISA (Cusabio, Wuhan, China). Plasma DEK levels were compared to tumor stage, response to therapy, and overall tumor burden in patients. Preliminary results demonstrate that DEK is indeed present in the plasma of HNSCC patients and we are currently comparing these levels to normal healthy controls. Further analyses are ongoing to determine whether DEK levels predict response to various treatment modalities, correlate with the body's immune response, and whether DEK presence in the serum will predict residual disease and/or early relapse. These data will be important to verify DEK plasma measurements as a clinically useful test and may give insight to future personalized and targeted treatment strategies for HNSCC. Citation Format: Trisha Wise-Draper, Lisa Privette Vinnedge, Arun Sendilnathan. The DEK oncogene may serve as a predictive plasma biomarker in head and neck cancer patients. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 584. doi:10.1158/1538-7445.AM2015-584

Oncogene- and drug resistance-associated alternative exon usage in acute myeloid leukemia (AML).

In addition to spliceosome gene mutations, oncogene expression and drug resistance in AML might influence exon expression. We performed exon-array analysis and exon-specific PCR (ESPCR) to identify specific landscapes of exon expression that are associated with DEK and WT1 oncogene expression and the resistance of AML cells to AraC, doxorubicin or azacitidine. Data were obtained for these five conditions through exon-array analysis of 17 cell lines and 24 patient samples and were extended through qESPCR of samples from 152 additional AML cases. More than 70% of AEUs identified by exon-array were technically validated through ESPCR. In vitro, 1,130 to 5,868 exon events distinguished the 5 conditions from their respective controls while in vivo 6,560 and 9,378 events distinguished chemosensitive and chemoresistant AML, respectively, from normal bone marrow. Whatever the cause of this effect, 30 to 80% of mis-spliced mRNAs involved genes unmodified at the whole transcriptional level. These AEUs unmasked new functional pathways that are distinct from those generated by transcriptional deregulation. These results also identified new putative pathways that could help increase the understanding of the effects mediated by DEK or WT1, which may allow the targeting of these pathways to prevent resistance of AML cells to chemotherapeutic agents.

The DEK oncoprotein and its emerging roles in gene regulation.

The DEK oncogene is highly expressed in cells from most human tissues and overexpressed in a large and growing number of cancers. It also fuses with the NUP214 gene to form the DEK-NUP214 fusion gene in a subset of acute myeloid leukemia. Originally characterized as a member of this translocation, DEK has since been implicated in epigenetic and transcriptional regulation, but its role in these processes is still elusive and intriguingly complex. Similarly multifaceted is its contribution to cellular transformation, affecting multiple cellular processes such as self-renewal, proliferation, differentiation, senescence and apoptosis. Recently, the roles of the DEK and DEK-NUP214 proteins have been elucidated by global analysis of DNA binding and gene expression, as well as multiple functional studies. This review outlines recent advances in the understanding of the basic functions of the DEK protein and its role in leukemogenesis.

DEK is a potential marker for aggressive phenotype and irinotecan-based therapy response in metastatic colorectal cancer.

BackgroundDEK is a transcription factor involved in stabilization of heterochromatin and cruciform structures. It plays an important role in development and progression of different types of cancer. This study aims to analyze the role of DEK in metastatic colorectal cancer.MethodsBaseline DEK expression was firstly quantified in 9 colorectal cell lines and normal mucosa by WB. SiRNA-mediated DEK inhibition was carried out for transient DEK silencing in DLD1 and SW620 to dissect its role in colorectal cancer aggressiveness. Irinotecan response assays were performed with SN38 over 24 hours and apoptosis was quantified by flow cytometry. Ex-vivo assay was carried out with 3 fresh tumour tissues taken from surgical resection and treated with SN38 for 24 hours. DEK expression was determined by immunohistochemistry in 67 formalin-fixed paraffin-embedded tumour samples from metastatic colorectal cancer patients treated with irinotecan-based therapy as first-line treatment.ResultsThe DEK oncogene is overexpressed in all colorectal cancer cell lines. Knock-down of DEK on DLD1 and SW620 cell lines decreased cell migration and increased irinotecan-induced apoptosis. In addition, low DEK expression level predicted irinotecan-based chemotherapy response in metastatic colorectal cancer patients with KRAS wild-type.ConclusionsThese data suggest DEK overexpression as a crucial event for the emergence of an aggressive phenotype in colorectal cancer and its potential role as biomarker for irinotecan response in those patients with KRAS wild-type status.

DEK oncogene expression during normal hematopoiesis and in Acute Myeloid Leukemia (AML)

DEK is important in regulating cellular processes including proliferation, differentiation and maintenance of stem cell phenotype. The translocation t(6;9) in Acute Myeloid Leukemia (AML), which fuses DEK with NUP214, confers a poor prognosis and a higher risk of relapse. The over-expression of DEK in AML has been reported, but different studies have shown diminished levels in pediatric and promyelocytic leukemias. This study has characterized DEK expression, in silico, using a large multi-center cohort of leukemic and normal control cases. Overall, DEK was under-expressed in AML compared to normal bone marrow (NBM). Studying specific subtypes of AML confirmed either no significant change or a significant reduction in DEK expression compared to NBM. Importantly, the similarity of DEK expression between AML and NBM was confirmed using immunohistochemistry analysis of tissue mircorarrays. In addition, stratification of AML patients based on median DEK expression levels indicated that DEK showed no effect on the overall survival of patients. DEK expression during normal hematopoiesis did reveal a relationship with specific cell types implicating a distinct function during myeloid differentiation. Whilst DEK may play a potential role in hematopoiesis, it remains to be established whether it is important for leukemagenesis, except when involved in the t(6;9) translocation.