Overexpression of DEK is an indicator of poor prognosis in patients with gastric adenocarcinoma

Radiomics and Ki-67 index predict survival in clear cell renal cell carcinoma

OBJECTIVE

To develop and validate predictive models based on Ki-67 index, radiomics, and Ki-67 index combined with radiomics for survival analysis of patients with clear cell renal cell carcinoma.

METHODS

This study enrolled 148 patients who were pathologically diagnosed as ccRCC between March 2010 and December 2018 at our institute. All tissue sections were collected and immunohistochemical staining was performed to calculate Ki-67 index. All patients were randomly divided into the training and validation sets in a 7:3 ratio. Regions of interests (ROIs) were segmented manually. Radiomics features were selected from ROIs in unenhanced, corticomedullary, and nephrographic phases. Multivariate Cox models based on the Ki-67 index and radiomics and univariate Cox models based on the Ki-67 index or radiomics alone were built; the predictive power was evaluated by the concordance (C)-index, integrated area under the curve, and integrated Brier Score.

RESULTS

Five features were selected to establish the prediction models of radiomics and combined model. The C-indexes of Ki-67 index model, radiomics model, and combined model were 0.741, 0.718, and 0.782 for disease-free survival (DFS); 0.941, 0.866, and 0.963 for overall survival, respectively. The predictive power of combined model was the best in both training and validation sets.

CONCLUSION

The survival prediction performance of combined model was better than Ki-67 model or radiomics model. The combined model is a promising tool for predicting the prognosis of patients with ccRCC in the future.

ADVANCES IN KNOWLEDGE

Both Ki-67 and radiomics have showed giant potential in prognosis prediction. There are few studies to investigate the predictive ability of Ki-67 combined with radiomics. This study intended to build a combined model and provide a reliable prognosis for ccRCC in clinical practice.

PG545 sensitizes ovarian cancer cells to PARP inhibitors through modulation of RAD51-DEK interaction

PG545 (Pixatimod) is a highly sulfated small molecule known for its ability to inhibit heparanase and disrupt signaling mediated by heparan-binding-growth factors (HB-GF). Previous studies indicated that PG545 inhibits growth factor-mediated signaling in ovarian cancer (OC) to enhance response to chemotherapy. Here we investigated the previously unidentified mechanisms by which PG545 induces DNA damage in OC cells and found that PG545 induces DNA single- and double-strand breaks, reduces RAD51 expression in an autophagy-dependent manner and inhibits homologous recombination repair (HRR). These changes accompanied the ability of PG545 to inhibit endocytosis of the heparan-sulfate proteoglycan interacting DNA repair protein, DEK, leading to DEK sequestration in the tumor microenvironment (TME) and loss of nuclear DEK needed for HRR. As a result, PG545 synergized with poly (ADP-ribose) polymerase inhibitors (PARPis) in OC cell lines in vitro and in 55% of primary cultures of patient-derived ascites samples ex vivo. Moreover, PG545/PARPi synergy was observed in OC cells exhibiting either de novo or acquired resistance to PARPi monotherapy. PG545 in combination with rucaparib also generated increased DNA damage, increased antitumor effects and increased survival of mice bearing HRR proficient OVCAR5 xenografts compared to monotherapy treatment in vivo. Synergistic antitumor activity of the PG545/rucaparib combination was likewise observed in an immunocompetent syngeneic ID8F3 OC model. Collectively, these results suggest that targeting DEK-HSPG interactions in the TME through the use of PG545 may be a novel method of inhibiting DNA repair and sensitizing cells to PARPis.

DEK modulates both expression and alternative splicing of cancer‑related genes

DEK is known to be a potential proto‑oncogene and is highly expressed in gastric cancer (GC); thus, DEK is considered to contribute to the malignant progression of GC. DEK is an RNA‑binding protein involved in transcription, DNA repair, and selection of splicing sites during mRNA processing; however, its precise function remains elusive due to the lack of clarification of the overall profiles of gene transcription and post‑transcriptional splicing that are regulated by DEK. We performed our original whole‑genomic RNA‑Seq data to analyze the global transcription and alternative splicing profiles in a human GC cell line by comparing DEK siRNA‑treated and control conditions, dissecting both differential gene expression and potential alternative splicing events regulated by DEK. The siRNA‑mediated knockdown of DEK in a GC cell line led to significant changes in gene expression of multiple cancer‑related genes including both oncogenes and tumor suppressors. Moreover, it was revealed that DEK regulated a number of alternative splicing in genes which were significantly enriched in various cancer‑related pathways including apoptosis and cell cycle processes. This study clarified for the first time that DEK has a regulatory effect on the alternative splicing, as well as on the expression, of numerous cancer‑related genes, which is consistent with the role of DEK as a possible oncogene. Our results further expand the importance and feasibility of DEK as a clinical therapeutic target for human malignancies including GC.

Long Non-Coding LEF1-AS1 Sponge miR-5100 Regulates Apoptosis and Autophagy in Gastric Cancer Cells via the miR-5100/DEK/AMPK-mTOR Axis

DEK and miR-5100 play critical roles in many steps of cancer initiation and progression and are directly or indirectly regulated by most promoters and repressors. LEF1-AS1 as a long non-coding RNA can regulate tumor development through sponge miRNA. The effect and regulatory mechanism of DEK on autophagy and apoptosis in gastric cancer (GC), and the role between miR-5100 and DEK or miR-5100 and LEF1-AS1 are still unclear. Our study found that DEK was highly expressed in gastric cancer tissues and cell lines, and knockdown of DEK inhibited the autophagy of cells, promoted apoptosis, and suppressed the malignant phenotype of gastric cancer. DEK regulates autophagy and apoptosis through the AMPK/mTOR signaling pathway. In addition, miR-5100 inhibits autophagy and promotes apoptosis in GC cells while LEF1-AS1 had the opposite effect. Studies have shown that miR-5100 acts by targeting the 3'UTR of DEK, and LEF1-AS1 regulates the expression of miR-5100 by sponging with mIR-5100. In conclusion, our results found that LEF1-AS1 and miR-5100 sponge function, and the miR-5100/DEK/AMPK/mTOR axis regulates autophagy and apoptosis in gastric cancer cells.

DEK is highly expressed in breast cancer and is associated with malignant phenotype and progression

DEK proto-oncogene (DEK) has been demonstrated as an oncogene and is associated with the development of many types of tumor; however, the expression and role of DEK in breast cancer remain unknown. The present study aimed to determine the role of DEK in the progression of breast cancer. The expression of DEK in 110 breast cancer tissues and 50 adjacent normal breast tissues was examined using immunohistochemistry. Furthermore, DEK expression was upregulated by DEK transfection or downregulated by DEK shRNA interference in MCF7 cells. Proliferative and invasive abilities were examined in MCF7 cells using MTT assay, colony-formation assay and transwell invasion assays. The results demonstrated that DEK expression level was significantly increased in breast cancer tissues compared with normal breast tissues. Furthermore, high DEK expression was associated with high histological grade, lymph node metastasis, advanced Tumor-Node-Metastasis stage and high Ki-67 index; however, DEK expression was not associated with the expression level of estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2. High DEK expression indicated poor prognosis in patients with breast cancer. DEK overexpression upregulated the protein expression of β-catenin and Wnt and increased the proliferative and invasive abilities of breast cancer cells. DEK downregulation had the opposite effect. Taken together, the results from the present study demonstrated that high expression of DEK was common in patients with breast cancer and was associated with progression of the disease and poor prognosis, and that DEK overexpression promoted the proliferative and invasive abilities of breast cancer cells.

DEK overexpression is predictive of poor prognosis in esophageal squamous cell carcinoma

INTRODUCTION

The DEK gene encodes a nuclear phosphoprotein which is involved in multiple cell metabolic processes, such as DNA damage repair, mRNA splicing, modifying chromatin structure and transcription regulation. DEK has been shown to be overexpressed in various solid human tumors and associated with patient prognosis. In this study, our aim was to investigate DEK protein expression and its relationship with clinicopathological parameters and prognosis in esophageal squamous cell carcinoma (ESCC).

MATERIAL AND METHODS

Tissue samples were collected from 120 routinely diagnosed ESCC patients who underwent surgical resection at the Zhongshan Hospital, Xiamen University in the period from June 2011 to May 2013. The expression of DEK was determined by immunohistochemistry.

RESULTS

DEK protein was ubiquitously distributed in the nucleus of ESCC cells, and its positive rate (71.7%) was significantly higher in cancer samples than those of para-carcinoma (21.4%) or normal esophageal (13.9%) tissues (p < 0.001). Similarly, significantly more cells overexpressing DEK were found in ESCC tissues (57.5%) in comparison with para-carcinoma samples (11.4%) and normal esophageal mucosa (0%, p < 0.001). The DEK overexpression rate was significantly different between patients with different tumor-node-metastasis (TNM) stages and differentiation degrees (p < 0.001). ESCC cases with elevated DEK amounts showed reduced disease-free and 5-year survival rates compared with those expressing low DEK amounts (p < 0.001). DEK overexpression was also confirmed to independently predict prognosis in ESCC (HR = 4.121, 95% CI: 1.803-9.42, p = 0.001).

CONCLUSIONS

DEK expression is positively correlated with reduced survival in ESCC patients. DEK has potential to be an independent biomarker in predicting prognosis of ESCC patients.

NUP214 in Leukemia: It's More than Transport

NUP214 is a component of the nuclear pore complex (NPC) with a key role in protein and mRNA nuclear export. Chromosomal translocations involving the NUP214 locus are recurrent in acute leukemia and frequently fuse the C-terminal region of NUP214 with SET and DEK, two chromatin remodeling proteins with roles in transcription regulation. SET-NUP214 and DEK-NUP214 fusion proteins disrupt protein nuclear export by inhibition of the nuclear export receptor CRM1, which results in the aberrant accumulation of CRM1 protein cargoes in the nucleus. SET-NUP214 is primarily associated with acute lymphoblastic leukemia (ALL), whereas DEK-NUP214 exclusively results in acute myeloid leukemia (AML), indicating different leukemogenic driver mechanisms. Secondary mutations in leukemic blasts may contribute to the different leukemia outcomes. Additional layers of complexity arise from the respective functions of SET and DEK in transcription regulation and chromatin remodeling, which may drive malignant hematopoietic transformation more towards ALL or AML. Another, less frequent fusion protein involving the C terminus of NUP214 results in the sequestosome-1 (SQSTM1)-NUP214 chimera, which was detected in ALL. SQSTM1 is a ubiquitin-binding protein required for proper autophagy induction, linking the NUP214 fusion protein to yet another cellular mechanism. The scope of this review is to summarize the general features of NUP214-related leukemia and discuss how distinct chromosomal translocation partners can influence the cellular effects of NUP214 fusion proteins in leukemia.

Clinicopathologic significance and prognostic value of Ki-67 expression in patients with gastric cancer: a meta-analysis

BACKGROUND

The prognostic value and clinicopathologic significance of Ki-67 expression in gastric cancer patients was controversial. This meta-analysis was performed to clarify the prognostic value and clinicopathologic significance of Ki-67 expression in gastric cancer patients.

MATERIALS AND METHODS

Several electronic databases were searched for eligible studies. The pooled odds ratio (OR), hazard ratios (HR) and 95% confidence interval(CI) were calculated to explore the prognostic value and clinicopathologic significance of Ki-67 expression for disease free survival and overall survival.

RESULTS

Totally 5600 gastric cancer patients from 29 studies were included in this study. High Ki-67 expression was significantly related with Lauren's classification (OR = 1.70; P = 0.001; 95%CI: 1.40-2.06) and tumor size(OR = 1.54; P = 0.006; 95%CI: 1.14-2.09). However, high Ki-67 expression was not significantly associated with lymph node metastasis (OR = 1.37; P = 0.138; 95% CI: 0.90-2.08) , tumor stage (OR = 1.31; P = 0.296; 95% CI: 0.79-2.16) and tumor differentiation (OR = 1.03; P = 0.839; 95% CI: 0.78-1.35). The pooled HRs were 1.87(P = 0.001; 95% CI 1.30-2.69) for disease free survival and 1.23(P = 0.005; 95% CI 1.06-1.42) for overall survival.

CONCLUSIONS

High Ki-67 expression may serve as a predictive biomarker for poor prognosis in gastric cancer patients. Stratification by Ki-67 expression may be a consideration for selection of therapeutic regimen and integrated managements.

The Art of War: harnessing the epigenome against cancer

Histone chaperones are indispensable regulators of chromatin structure and function. Recent work has shown that they are frequently mis-regulated in cancer, which can have profound consequences on tumor growth and survival. Here, we focus on chaperones for the essential H3 histone variants H3.3 and CENP-A, specifically HIRA, DAXX/ATRX, DEK, and HJURP. This review summarizes recent studies elucidating their roles in regulating chromatin and discusses how cancer-specific chromatin interactions can be exploited to target cancer cells.

The nuclear DEK interactome supports multi-functionality

DEK is an oncoprotein that is overexpressed in many forms of cancer and participates in numerous cellular pathways. Of these different pathways, relevant interacting partners and functions of DEK are well described in regard to the regulation of chromatin structure, epigenetic marks, and transcription. Most of this understanding was derived by investigating DNA-binding and chromatin processing capabilities of the oncoprotein. To facilitate the generation of mechanism-driven hypotheses regarding DEK activities in underexplored areas, we have developed the first DEK interactome model using tandem-affinity purification and mass spectrometry. With this approach, we identify IMPDH2, DDX21, and RPL7a as novel DEK binding partners, hinting at new roles for the oncogene in de novo nucleotide biosynthesis and ribosome formation. Additionally, a hydroxyurea-specific interaction with replication protein A (RPA) was observed, suggesting that a DEK-RPA complex may form in response to DNA replication fork stalling. Taken together, these findings highlight diverse activities for DEK across cellular pathways and support a model wherein this molecule performs a plethora of functions.

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.

Prognostic role of DEK in human solid tumors: a meta-analysis

Recently, the oncogenic role of DEK has been recognized in several cancer types. However, its prognostic role in human solid tumor remains unclear. Thus, the present meta-analysis, based on 14 published studies (2208 patients) searched from PubMed, Web of Science, and EMBASE databases, assessed the prognostic value of DEK in human solid tumors. Furthermore, the pooled hazard ratio (HR) for overall survival (OS) was evaluated with fixed-effects models. A subgroup analysis was also performed according to the patients' ethnicities and tumor types. Data from these published studies were extracted, and the results showed that the overexpression of DEK was significantly associated with poor OS in human solid tumors. The combined hazards ratio was (HR = 1.83; 95% CI, 1.64-2.05, P < 0.00001) for OS (univariable analysis) with a fixed-effects model without any significant heterogeneity (P = 0.71, I² = 0%). The combined HR was (HR = 1.70; 95% CI, 1.48-1.96, P < 0.00001) for OS (multivariable analysis) with a fixed-effects model, and no significant heterogeneity was observed (P = 0.36, I² = 9%). Therefore, the overexpression of DEK was correlated with poor survival in human solid tumors, which suggests that the expression status of DEK is a valuable biomarker for the prediction of prognosis and serves as a novel therapeutic target in human solid tumors.

A role for intracellular and extracellular DEK in regulating hematopoiesis

PURPOSE OF REVIEW

Hematopoietic stem/progenitor cell fate decision during hematopoiesis is regulated by intracellular and extracellular signals such as transcription factors, growth factors, and cell-to-cell interactions. In this review, we explore the function of DEK, a nuclear phosphoprotein, on gene regulation. We also examine how DEK is secreted and internalized by cells, and discuss how both endogenous and extracellular DEK regulates hematopoiesis. Finally, we explore what currently is known about the regulation of DEK during inflammation.

RECENT FINDINGS

DEK negatively regulates the proliferation of early myeloid progenitor cells but has a positive effect on the differentiation of mature myeloid cells. Inflammation regulates intracellular DEK concentrations with inflammatory stimuli enhancing DEK expression. Inflammation-induced nuclear factor-kappa B activation is regulated by DEK, resulting in changes in the production of other inflammatory molecules such as IL-8. Inflammatory stimuli in turn regulates DEK secretion by cells of hematopoietic origin. However, how inflammation-induced expression and secretion of DEK regulates hematopoiesis remains unknown.

SUMMARY

Understanding how DEK regulates hematopoiesis under both homeostatic and inflammatory conditions may lead to a better understanding of the biology of HSCs and HPCs. Furthering our knowledge of the regulation of hematopoiesis will ultimately lead to new therapeutics that may increase the efficacy of hematopoietic stem cell transplantation.