Derlin-1 is overexpressed in human breast carcinoma and protects cancer cells from endoplasmic reticulum stress-induced apoptosis

miR-181c-5p/DERL1 pathway controls breast cancer progression mediated by TRAF6-linked K63 ubiquitination of AKT

BACKGROUND

Aberrant Derlin-1 (DERL1) expression is associated with an overactivation of p-AKT, whose involvement in breast cancer (BRCA) development has been widely speculated. However, the precise mechanism that links DERL1 expression and AKT activation is less well-studied.

METHODS

Bioinformatic analyses hold a promising approach by which to detect genes' expression levels and their association with disease prognoses in patients. In the present work, a dual-luciferase assay was employed to investigate the relationship between DERL1 expression and the candidate miRNA by both in vitro and in vivo methods. Further in-depth studies involving immunoprecipitation-mass spectrum (IP-MS), co-immunoprecipitation (Co-IP), as well as Zdock prediction were performed.

RESULTS

Overexpression of DERL1 was detected in all phenotypes of BRCA, and its knockdown showed an inhibitory effect on BRCA cells both in vitro and in vivo. The Cancer Genome Atlas (TCGA) database reported that DERL1 overexpression was correlated with poor overall survival in BRCA cases, and so the quantification of DERL1 expression could be a potential marker for the clinical diagnosis of BRCA. On the other hand, miR-181c-5p was downregulated in BRCA, suggesting that its overexpression could be a potent therapeutic route to improve the overall survival of BRCA cases. Prior bioinformatic analyses indicated a somewhat positive correlation between DERL1 and TRAF6 as well as between TRAF6 and AKT, but not between miR-181c-5p and DERL1. In retrospect, DERL1 overexpression promoted p-AKT activation through K63 ubiquitination. DERL1 was believed to directly interact with the E3 ligase TRAF6. As Tyr77Ala or Tyr77Ala/Gln81Ala/Arg85Ala/Val158Ala attempts to prevent the interaction between DERL1 and TRAF domain of TRAF6, resulted in a significant reduction in K63-ubiquitinated p-AKT production. However, mutations in Gln81Ala, Arg85Ala, or Val158Ala could possibly interrupt with these processes.

CONCLUSIONS

Our data confirm that mediation of the miR-181c-5p/DERL1 pathway by TRAF6-linked AKT K63 ubiquitination holds one of the clues to set our focus on toward meeting the therapeutic goals of BRCA.

Proteotoxic stress and the ubiquitin proteasome system

The ubiquitin proteasome system maintains protein homeostasis by regulating the breakdown of misfolded proteins, thereby preventing misfolded protein aggregates. The efficient elimination is vital for preventing damage to the cell by misfolded proteins, known as proteotoxic stress. Proteotoxic stress can lead to the collapse of protein homeostasis and can alter the function of the ubiquitin proteasome system. Conversely, impairment of the ubiquitin proteasome system can also cause proteotoxic stress and disrupt protein homeostasis. This review examines two impacts of proteotoxic stress, 1) disruptions to ubiquitin homeostasis (ubiquitin stress) and 2) disruptions to proteasome homeostasis (proteasome stress). Here, we provide a mechanistic description of the relationship between proteotoxic stress and the ubiquitin proteasome system. This relationship is illustrated by findings from several protein misfolding diseases, mainly neurodegenerative diseases, as well as from basic biology discoveries from yeast to mammals. In addition, we explore the importance of the ubiquitin proteasome system in endoplasmic reticulum quality control, and how proteotoxic stress at this organelle is alleviated. Finally, we highlight how cells utilize the ubiquitin proteasome system to adapt to proteotoxic stress and how the ubiquitin proteasome system can be genetically and pharmacologically manipulated to maintain protein homeostasis.

Multiomics insights on the onset, progression, and metastatic evolution of breast cancer

Breast cancer is the most common malignant neoplasm in women. Despite progress to date, 700,000 women worldwide died of this disease in 2020. Apparently, the prognostic markers currently used in the clinic are not sufficient to determine the most appropriate treatment. For this reason, great efforts have been made in recent years to identify new molecular biomarkers that will allow more precise and personalized therapeutic decisions in both primary and recurrent breast cancers. These molecular biomarkers include genetic and post-transcriptional alterations, changes in protein expression, as well as metabolic, immunological or microbial changes identified by multiple omics technologies (e.g., genomics, epigenomics, transcriptomics, proteomics, glycomics, metabolomics, lipidomics, immunomics and microbiomics). This review summarizes studies based on omics analysis that have identified new biomarkers for diagnosis, patient stratification, differentiation between stages of tumor development (initiation, progression, and metastasis/recurrence), and their relevance for treatment selection. Furthermore, this review highlights the importance of clinical trials based on multiomics studies and the need to advance in this direction in order to establish personalized therapies and prolong disease-free survival of these patients in the future.

TOLLIP-mediated autophagic degradation pathway links the VCP-TMEM63A-DERL1 signaling axis to triple-negative breast cancer progression

Triple-negative breast cancer (TNBC) is the most challenging breast cancer subtype to treat due to the lack of effective targeted therapies. Transmembrane (TMEM) proteins represent attractive drug targets for cancer therapy, but biological functions of most members of the TMEM family remain unknown. Here, we report for the first time that TMEM63A (transmembrane protein 63A), a poorly characterized TMEM protein with unknown functions in human cancer, functions as a novel oncogene to promote TNBC cell proliferation, migration, and invasion in vitro and xenograft tumor growth and lung metastasis in vivo. Mechanistic investigations revealed that TMEM63A localizes in endoplasmic reticulum (ER) and lysosome membranes, and interacts with VCP (valosin-containing protein) and its cofactor DERL1 (derlin 1). Furthermore, TMEM63A undergoes autophagy receptor TOLLIP-mediated autophagic degradation and is stabilized by VCP through blocking its lysosomal degradation. Strikingly, TMEM63A in turn stabilizes oncoprotein DERL1 through preventing TOLLIP-mediated autophagic degradation. Notably, pharmacological inhibition of VCP by CB-5083 or knockdown of DERL1 partially abolishes the oncogenic effects of TMEM63A on TNBC progression both in vitro and in vivo. Collectively, these findings uncover a previously unknown functional and mechanistic role for TMEM63A in TNBC progression and provide a new clue for targeting TMEM63A-driven TNBC tumors by using a VCP inhibitor.Abbreviations: ATG16L1, autophagy related 16 like 1; ATG5, autophagy related 5; ATP5F1B/ATP5B, ATP synthase F1 subunit beta; Baf-A1, bafilomycin A₁; CALCOCO2/NDP52, calcium binding and coiled-coil domain 2; CANX, calnexin; DERL1, derlin 1; EGFR, epidermal growth factor receptor; ER, endoplasmic reticulum; ERAD, endoplasmic reticulum-associated degradation; HSPA8, heat shock protein family A (Hsp70) member 8; IP, immunoprecipitation; LAMP2A, lysosomal associated membrane protein 2; NBR1, NBR1 autophagy cargo receptor; OPTN, optineurin; RT-qPCR, reverse transcription-quantitative PCR; SQSTM1/p62, sequestosome 1; TAX1BP1, Tax1 binding protein 1; TMEM63A, transmembrane protein 63A; TNBC, triple-negative breast cancer; TOLLIP, toll interacting protein; VCP, valosin containing protein.

The Role of the Rhomboid Superfamily in ER Protein Quality Control: From Mechanisms and Functions to Diseases

The endoplasmic reticulum (ER) is an essential organelle in eukaryotic cells and is a major site for protein folding, modification, and lipid synthesis. Perturbations within the ER, such as protein misfolding and high demand for protein folding, lead to dysregulation of the ER protein quality control network and ER stress. Recently, the rhomboid superfamily has emerged as a critical player in ER protein quality control because it has diverse cellular functions, including ER-associated degradation (ERAD), endosome Golgi-associated degradation (EGAD), and ER preemptive quality control (ERpQC). This breadth of function both illustrates the importance of the rhomboid superfamily in health and diseases and emphasizes the necessity of understanding their mechanisms of action. Because dysregulation of rhomboid proteins has been implicated in various diseases, such as neurological disorders and cancers, they represent promising potential therapeutic drug targets. This review provides a comprehensive account of the various roles of rhomboid proteins in the context of ER protein quality control and discusses their significance in health and disease.

Identification of personalized neoantigen-based vaccines and immune subtype characteristic analysis of glioblastoma based on abnormal alternative splicing

The development of personalized neoantigen-based vaccines in cancer immunotherapy has shown promise. In this study, a large-scale bioinformatics analysis was performed to identify potential GBM-associated neoantigens based on abnormal alternative splicing, and then screen suitable patients for vaccination. Gene expression profiles and clinical information were collected from TCGA. We filtered the percent-spliced-in (PSI) spectrum of alternative splicing events in the dataset to identify abnormal alternative splicing events. MAF package was used to identify and analyse tumour mutation burden (TMB) in cancer samples. Tumour Immune Estimation Resource (TIMER) was used to calculate and visualize the infiltration of antigen presenting cells (APCs). In addition, consistent clustering algorithm utilized to identify immune subtypes of GBM. Five potential tumour neoantigens (LRP1, TCF12, DERL3, WIPI2, and TSHZ3) were identified in GBM by selecting genes both with abnormal alternative splicing (upregulated) and gene frameshift mutations, in which LRP1 was significantly associated with APCs. According to the expressions of five potential tumour neoantigens, 160 patients with GBM were divided into three immune subtypes. Patients in cluster3 exhibited good prognoses. Furthermore, the characteristics, including TMB, abnormal alternative splicing events, immune activity, immune cells proportion, and association with tumour biomarkers, were unique in each immune subtypes. The characteristics of cluster3 illustrated that cluster3 participants were more suitable candidates for vaccination. LRP1 was identified as a potential neoantigen for immunotherapy against GBM, and patients in cluster3 were more suitable for vaccination. Our findings provide important guidance for the development of novel neoantigens and therapeutic targets in patients with GBM.

Breast Cancer Genomics: Primary and Most Common Metastases

Specific genomic alterations have been found in primary breast cancer involving driver mutations that result in tumorigenesis. Metastatic breast cancer, which is uncommon at the time of disease onset, variably impacts patients throughout the course of their disease. Both the molecular profiles and diverse genomic pathways vary in the development and progression of metastatic breast cancer. From the most common metastatic site (bone), to the rare sites such as orbital, gynecologic, or pancreatic metastases, different levels of gene expression indicate the potential involvement of numerous genes in the development and spread of breast cancer. Knowledge of these alterations can, not only help predict future disease, but also lead to advancement in breast cancer treatments. This review discusses the somatic landscape of breast primary and metastatic tumors.

The regulatory landscape of retinoblastoma: a pathway analysis perspective

Retinoblastoma (Rb) is a rare intraocular tumour in early childhood, with an approximate incidence of 1 in 18 000 live births. Experimental studies for Rb are complex due to the challenges associated with obtaining a normal retina to contrast with diseased tissue. In this work, we reanalyse a dataset that contains normal retina samples. We identified the individual genes whose expression is different in Rb in contrast with normal tissue, determined the pathways whose global expression pattern is more distant from the global expression observed in normal tissue, and finally, we identified which transcription factors regulate the highest number of differentially expressed genes (DEGs) and proposed as transcriptional master regulators (TMRs). The enrichment of DEGs in the phototransduction and retrograde endocannabinoid signalling pathways could be associated with abnormal behaviour of the processes leading to cellular differentiation and cellular proliferation. On the other hand, the TMRs nuclear receptor subfamily 5 group A member 2 and hepatocyte nuclear factor 4 gamma are involved in hepatocyte differentiation. Therefore, the enrichment of aberrant expression in these transcription factors could suggest an abnormal retina development that could be involved in Rb origin and progression.

Organelles coordinate milk production and secretion during lactation: Insights into mammary pathologies

The mammary gland undergoes a spectacular series of changes during its development and maintains a remarkable capacity to remodel and regenerate during progression through the lactation cycle. This flexibility of the mammary gland requires coordination of multiple processes including cell proliferation, differentiation, regeneration, stress response, immune activity, and metabolic changes under the control of diverse cellular and hormonal signaling pathways. The lactating mammary epithelium orchestrates synthesis and apical secretion of macromolecules including milk lipids, milk proteins, and lactose as well as other minor nutrients that constitute milk. Knowledge about the subcellular compartmentalization of these metabolic and signaling events, as they relate to milk production and secretion during lactation, is expanding. Here we review how major organelles (endoplasmic reticulum, Golgi apparatus, mitochondrion, lysosome, and exosome) within mammary epithelial cells collaborate to initiate, mediate, and maintain lactation, and how study of these organelles provides insight into options to maintain mammary/breast health.

Derlin-1, as a Potential Early Predictive Biomarker for Nonresponse to Infliximab Treatment in Rheumatoid Arthritis, Is Related to Autophagy

Background

The goal of this study was to identify potential predictive biomarkers for the therapeutic effect of infliximab (IFX) in Rheumatoid arthritis (RA) and explore the potential molecular mechanism of nonresponse to IFX treatment to achieve individualized treatment of RA.

Methods

Differential gene expression between IFX responders and nonresponders in the GSE58795 and GSE78068 datasets was identified. Coexpression analysis was used to identify the modules associated with nonresponse to IFX therapy for RA, and enrichment analysis was conducted on module genes. Least absolute shrink and selection operator (LASSO) regression was used to develop a gene signature for predicting the therapeutic effect of IFX in RA, and the area under the receiver operating characteristic curve (AUC) was used to evaluate the predictive value of the signature. Correlation analysis and single-sample gene set enrichment analysis (ssGSEA) were used to explore the potential role of the hub genes. Experimental validation was conducted in synovial tissue and RA fibroblast-like synoviocytes (RA-FLSs).

Results

A total of 46 common genes were obtained among the two datasets. The yellow-green module was identified as the key module associated with nonresponse to IFX therapy for RA. We identified a 25-gene signature in GSE78068, and the AUC for the signature was 0.831 in the internal validation set and 0.924 in the GSE58795 dataset(external validation set). Derlin-1 (DERL1) was identified as the hub gene and demonstrated to be involved in the immune response and autophagy regulation. DERL1 expression was increased in RA synovial tissue compared with OA synovial tissue, and DERL1-siRNA partially inhibited autophagosome formation in RA-FLSs.

Conclusion

The 25-gene signature may have potential predictive value for the therapeutic effect of IFX in RA at the beginning of IFX treatment, and autophagy may be involved in nonresponse to IFX treatment. In particular, DERL1 may be associated with the regulation of autophagy.

MicroRNA-375-3p Suppresses Upper Tract Urothelial Carcinoma Cell Migration and Invasion via Targeting Derlin-1

Little is known regarding the molecular characterization of upper tract urothelial carcinoma (UTUC). Novel therapeutic targets and prognostic predictors are imminent. In the present study, we aim to examine the oncogenic function and molecular mechanism of Derlin-1 in UTUC. Derlin-1 overexpression is significantly associated with poor prognosis in patients with UTUC. In vitro, knockdown or over-expression of Derlin-1 markedly regulated UTUC cell invasion and migration. We further discovered miR-375-3p suppresses cell invasion and migration by inversely regulating Derlin-1 and blocking EMT in UTUC cells. Taking this together, miR-375-3p functions as a tumor suppressive microRNA by directly targeting Derlin-1 and blocking epithelial-mesenchymal transition (EMT) in UTUC.

Melatonin enhances cisplatin-induced cell death through inhibition of DERL1 in mesenchymal-like CD44high OSCC cells

BACKGROUND

Melatonin is a hormone that is primarily produced in the pineal gland and is involved in wide range of biological functions. However, the impact of melatonin on chemotherapy-induced cell death remains to be elucidated in oral squamous cell carcinoma (OSCC) cells. The objective of this study was to clarify the role of melatonin in cisplatin-induced cytotoxicity in CD44^high OSCC cells.

METHODS

CD44^high OSCC cells were cultured on fibronectin-coated hydrogel. A lactate dehydrogenase cytotoxicity assay was performed to evaluate cisplatin-induced cell death. The effect of melatonin on cisplatin-induced cell death and Derlin-1 (DERL1) endoplasmic reticulum membrane protein expression was investigated.

RESULTS

CD44^high OSCC cells exhibited mesenchymal-like features when cultured on fibronectin-coated hydrogel. Mesenchymal-like CD44^high OSCC cells demonstrated strong resistance to cisplatin-induced cell death compared with epithelial-like CD44^high OSCC cells. DERL1 mRNA and DERL1 protein expression levels were significantly higher in mesenchymal-like CD44^high cells compared with epithelial-like CD44^high cells. Cisplatin-induced cell death was significantly enhanced after DERL1 siRNA knockdown, suggesting that DERL1 is involved in resistance to cisplatin-induced cell death. Melatonin significantly inhibited DERL1 expression and enhanced cisplatin-induced cell death in mesenchymal-like CD44^high cells. miR-181c-5p expression was significantly upregulated in the presence of melatonin. Furthermore, melatonin-inhibited DERL1 expression was significantly recovered by miR-181c-5p inhibitor. In addition, melatoninenhanced cisplatin-induced cell death was attenuated by miR-181c-5p inhibitor. These results suggest that melatonin-induced miR-181c-5p enhances cisplatin-induced cell death through inhibition of DERL1 in mesenchymal-like CD44^high cells.

CONCLUSIONS

Melatonin plays a vital role in promoting cisplatin-induced cytotoxicity in mesenchymal-like CD44^high OSCC cells.

[Mechanism of DERL3 Affecting the Proliferation, Invasion and Metastasis of Lung Adenocarcinoma A549 Cells]

BACKGROUND

Derlin 3 (DERL3) is downregulated in colorectal cancer (CRC) samples. Its level is closely linked to lymphatic metastasis or distant metastasis rate in CRC patients. However, its biological behavior in lung adenocarcinoma were rarely reported. The aim of this study is to investigate the ectopic expression of DERL3 in lung adenocarcinoma tissues and its effect on the invasion and metastasis of lung adenocarcinoma A549 cell line to reveal the possible mechanism of invasion and metastasis of lung adenocarcinoma.

METHODS

Lung adenocarcinoma microarray gene chip data included 3 cases of lymph node metastasis and 3 cases of lung adenocarcinoma tissue without lymph node metastasis. The GEDS and Kaplan-Meier plot queries the survival curve and expression level of DERL3. Western blot was used to detect the expression of DERL3 in lung adenocarcinoma cells. The efficiency of knockdown DERL3 gene was detected by Western blot assay. Transwell detected the number of cells passing through the basement membrane of the transwell. EDU assay detected cell proliferation ability. Western blot detected the expression of epithelial-mesenchymal transition related proteins E-cadherin and Vimentin.

RESULTS

The microarray gene chip results showed that compared with lung adenocarcinoma tissues without lymph node metastasis, 1,314 mRNAs in lung adenocarcinoma tissues with lymph node metastasis were up-regulated, 400 mRNAs were down (P<0.05). The expression of DERL3 increased in lung adenocarcinoma (P<0.05). The results of survival curve showed that the lung cancer patients with high expression of DERL3 with poor prognosis (P<0.05). Western blot results indicated that plasmid transfection was successful. Knockdown of DERL3 suppressed the ability of proliferation, invasion and migration in A549 cells (P<0.05). After knockdown of DERL3, the expression level of Vimentin was decreased, while E-cadherin expression increased (P<0.05).

CONCLUSIONS

Knockdown of DERL3 inhibited the proliferation, invasion and metastasis of A549 cells.

Temporal Quantitative Proteomics Reveals Proteomic and Phosphoproteomic Alterations Associated with Adaptive Response to Hypoxia in Melanoma Cells

Simple Summary

Most solid tumours, including melanoma (skin cancer), are riddled with areas lacking adequate oxygen supply due to insufficient vasculature. Cancer cells in these regions are resistant to therapies and contribute to cancer spread and poor treatment response in patients. Understanding the mechanisms by which cancer cells adapt to survive in such a hostile environment will provide novel avenues for treatment. In this study, we investigated mechanisms that melanoma cells use to adapt and survive in an oxygen-poor environment. We used four different melanoma cell lines and studied how protein levels and phosphorylation patterns on thousands of proteins change when the cells are exposed to poor oxygen conditions. This revealed potential mechanisms on which cancer cells are dependent for survival. These survival mechanisms can be potentially targeted to achieve durable response to therapy. We demonstrate this by targeting one such mechanism required for cancer cell survival.

Abstract

Hypoxia is a common feature in various solid tumours, including melanoma. Cancer cells in hypoxic environments are resistant to both chemotherapy and radiation. Hypoxia is also associated with immune suppression. Identification of proteins and pathways that regulate cancer cell survival in hypoxic environments can reveal potential vulnerabilities that can be exploited to improve the efficacy of anticancer therapies. We carried out temporal proteomic and phosphoproteomic profiling in melanoma cell lines to identify hypoxia-induced protein expression and phosphorylation changes. By employing a TMT-based quantitative proteomics strategy, we report the identification and quantitation of >7000 proteins and >10,000 phosphosites in melanoma cell lines grown in hypoxia. Proteomics data show metabolic reprogramming as one of the prominent adaptive responses in hypoxia. We identify several novel hypoxia-mediated phosphorylation changes that have not been reported before. They reveal kinase signalling pathways that are potentially involved in modulating cellular response to hypoxia. In addition to known protein expression changes, we identify several novel proteomic alterations associated with adaptive response to hypoxia. We show that cancer cells require the ubiquitin–proteasome system to survive in both normoxia and hypoxia. Inhibition of proteasome activity affects cell survival and may provide a novel therapeutic avenue to target cancer cells in hypoxia. Our study can serve as a valuable resource to pursue novel candidates to target hypoxia in cancers and improve the efficacy of anticancer therapies.

The role of rhomboid superfamily members in protein homeostasis: Mechanistic insight and physiological implications

Cells are equipped with protein quality control pathways in order to maintain a healthy proteome; a process known as protein homeostasis. Dysfunction in protein homeostasis leads to the development of many diseases that are associated with proteinopathies. Recently, the rhomboid superfamily has attracted much attention concerning their involvement in protein homeostasis. While their functional role has become much clearer in the last few years, their systemic significance in mammals remains elusive. Here we delineate the current knowledge of rhomboids in protein quality control and how these functions are integrated at the organismal level.

Derlin-1 Promotes the Progression of Human Hepatocellular Carcinoma via the Activation of AKT Pathway

Introduction

Hepatocellular carcinoma (HCC) is the third leading cause of cancer death worldwide. In the present research, we explored a new oncogene, derlin-1 (DERL1), and studied its role and mechanism in human HCC.

Methods

We assessed the expression and prognosis value of DERL1 in human HCC by using GEPIA dataset analysis and immunohistochemistry. To elucidate the specific function of DERL1, we suppressed its expression in two HCC cell lines, HuH7 and Hep3B, and overexpressed DERL1 in Hep3B cells. Cell proliferation and migration was detected by CCK8 and transwell assays. Cell flow cytometry was used to evaluate cell apoptosis.

Results

Our results demonstrated that DERL1 was highly expressed in HCC samples (n = 369) than in normal samples (n = 160). Similar results were obtained in 60 clinical samples that we collected from the local hospital. The high expression rate of DERL1 reached 78.3% (47/60). DERL1 overexpression samples were concentrated in patients with tumor diameters >5cm or lymph node metastases. Thus, we speculated that DERL1 operated as a tumor promotor in HCC, and its expression might be proposed as a predictor for tumor metastasis of human HCC. Interference of DERL1 markedly blocked cell proliferation and migration, and induced the apoptosis of HCC cells in vitro. Phosphorylation of Akt was significantly inhibited in cells transfected with DERL1 siRNA compared to their control cells in HuH7 and Hep3B cell lines. The opposite result was observed in the DERL1 overexpression cells.

Conclusion

Our findings prove that DERL1 promotes tumor progression via AKT pathway and provide a new potential target for the clinical treatment and diagnosis of human HCC.

Role of circular RNAs in brain development and CNS diseases

In mammals, many classes of noncoding RNAs (ncRNAs) are expressed at a much higher level in the brain than in other organs. Recent studies have identified a new class of ncRNAs called circular RNAs (circRNAs), which are produced by back-splicing and fusion of either exons, introns, or both exon-intron into covalently closed loops. The circRNAs are also highly enriched in the brain and increase continuously from the embryonic to the adult stage. Although the functional significance and mechanism of action of circRNAs are still being actively explored, they are thought to regulate the transcription of their host genes and sequestration of miRNAs and RNA binding proteins. Some circRNAs are also shown to have translation potential to form peptides. The expression and abundance of circRNAs seem to be spatiotemporally maintained in a normal brain. Altered expression of circRNAs is also thought to mediate several disorders, including brain-tumor growth, and acute and chronic neurodegenerative disorders by affecting mechanisms such as angiogenesis, neuronal plasticity, autophagy, apoptosis, and inflammation. This review discusses the involvement of various circRNAs in brain development and CNS diseases. A better understanding of the circRNA function will help to develop novel therapeutic strategies to treat CNS complications.

Derlin-1 functions as a growth promoter in breast cancer

Breast cancer is one of the most common malignant tumors in women. Derlin-1 has been found to be overexpressed in several human cancers in addition to playing an important role in tumor processes; however, the expression patterns and functions of Derlin-1 in human breast cancer are not fully understood. In this study, we found that Derlin-1 overexpression was higher in breast cancer compared to normal samples through TCGA and GTEx database analyses. Kaplan-Meier plotter analysis showed that Derlin-1 was a predicting factor for patient prognosis. Derlin-1 expression was significantly up-regulated in breast cancer tissues (18/30, 60.00%) compared to corresponding paracancerous tissue (9/30, 30.00%, p < 0.05) as detected by immunohistochemistry, and the expression of Derlin-1 was correlated to pathological grading. siRNA interference of Derlin-1 inhibited cell proliferation, which is associated with the promotion of apoptosis and migration. Derlin-1 knockdown suppressed the protein levels of p-AKT and Cyclin D1 while up-regulating Caspase3 and Bax. GEPIA database analysis showed that MTDH and ATAD2 were downstream target genes, and the expression of MTDH and was suppressed in Derlin-1 knockdown cells. Taken together, our results demonstrated ATAD2 that Derlin-1 is overexpressed in breast cancer and promoted a malignant phenotype through the AKT signaling pathway.

MicroRNA-575 targets Derlin 1 to regulate proliferation, migration and invasion of human thyroid cancer cells

INTRODUCTION

This study was undertaken to examine the expression of miR-575 in thyroid cancer tissues and to explore its therapeutic potential.

MATERIAL AND METHODS

Expression analysis was carried out by qRT-PCR. The MTT assay was used for cell viability. DAPI and annexin V/PI assays were used to detect apoptosis. Wound healing and Transwell assays were used for cell migration and invasion respectively. Western blot analysis was used to determine the expression of proteins.

RESULTS

The results showed significant downregulation of miR-575 in thyroid cancer tissues and cell lines. The role of miR-575 was deciphered by overexpression of miR-575 in MDA-T32 and MDA-T68 thyroid cancer cells. The results showed that overexpression of miR-575 caused significant inhibition of the proliferation of the MDA-T32 and MDA-T68 cells via induction of apoptotic cell death. The expression of Bax was also enhanced while that of Bax was decreased upon miR-575 overexpression in MDA-T32 and MDA-T68 cells. Additionally, miR-575 overexpression inhibited the migration and invasion of the MDA-T32 and MDA-T68 thyroid cancer cells. Bioinformatic approaches and the dual luciferase assay indicated Derlin 1 (DERL1) to be the potential target of miR-575 in thyroid cancer. DERL1 was significantly upregulated in thyroid cancer tissues and cell lines and overexpression of miR-575 caused suppression of DERL1 in MDA-T68 cells. Silencing of DERL1 inhibited the proliferation of the MDA-T68 cells while overexpression of DERL1 could abolish the effects of miR-575 overexpression on the proliferation of MDA-T68 thyroid cancer cells.

CONCLUSIONS

miR-575 may be used as a therapeutic target for thyroid cancer treatment.

Derlin-1 exhibits oncogenic activities and indicates an unfavorable prognosis in breast cancer

Derlin-1 is involved in the elimination of misfolded proteins and has been implicated in the progression of human cancers. However, its prognostic value and biological function in breast cancer remain unknown. Here, we show that Derlin-1 is overexpressed in breast cancer and exhibits oncogenic activities via interaction with UBE2C. Increased expression of Derlin-1 is correlated with lymph node metastasis, advanced clinical stage, and unfavorable overall survival in two cohorts containing over 1,000 patients. Multivariate analyses by the Cox regression model suggest Derlin-1 is an independent factor for poor prognosis. In vitro experiments demonstrate that Derlin-1 expression is transcriptionally upregulated by c-Myc. Ectopic expression of Derlin-1 promotes breast cancer cell proliferation and migration, whereas the knockdown of Derlin-1 results in the opposite phenotypes. Mechanistically, Derlin-1 directly binds to UBE2C to increase the phosphorylation of AKT and ERK. The treatment of UBE2C siRNA markedly attenuates Derlin-1-mediated cell growth and migration. Collectively, our data suggest Derlin-1 is a potential prognostic factor and functions as an oncogene in breast cancer.

Derlin1 functions as an oncogene in cervical cancer via AKT/mTOR signaling pathway

BACKGROUND

Cervical cancer (CC) ranks third in the morbidity and mortality of female cancer around the world. Derlin1 has been found to be overexpressed in several human cancers. However, it is still unclear about its roles in CC. The research aims to explore the relationship between Derlin1 and CC.

METHODS

We purchased a human CC tissues microarray, which contained CC tissues and corresponding para-cancerous tissues from 93 patients with primary cervical squamous cell carcinoma. Immunohistochemical staining was used to confirm the expression of Derlin1 in these tissues. And we detected the differential expression of Derlin1 in cervical cancer cell lines and normal cervical epithelial cells (H8). Further, the cervical cancer cell lines SiHa and C33A were used as an in vitro model, which was down-regulated the expression of Derlin1 using siRNA interference technology. The effects of Derlin1 down-regulating in CC cell lines on cell proliferation and migration were detected by CCK8 assay and transwell assay, respectively. The effect of Derlin1 down-regulating on apoptosis was analyzed by flow cytometry, and apoptosis-related proteins were detected using western blotting. In-depth mechanisms were studied using western blotting. In addition, the effects of Derlin1 up-regulating in normal cervical epithelial cells also were exposed.

RESULTS

Derlin1 was significantly elevated in CC tissues (81.7%, 76/93), and the expression of Derlin1 was positively correlated with the tumor size, pathological grade, and lymph node metastasis in CC patients. And Derlin1 was high expressed in cervical cancer cell lines compared to H8 cells. Knockdown of Derlin1 in cervical cancer cell lines inhibited cell proliferation and migration. Moreover, knockdown of Derlin1 induced apoptosis and affected the expression of apoptosis-related proteins, including Bcl-2, Bax, Bim, caspase3 and caspase9. Further experiments showed that AKT/mTOR signal pathway might be involve in this processes that knockdown of Derlin1 inhibited the expression of p-AKT and p-mTOR. Over-expression of Derlin1 in H8 cells promoted cell proliferation and migration via up-regulated the expression of p-AKT and p-mTOR.

CONCLUSION

Derlin1 is an oncogene in CC via AKT/mTOR pathway. It might be a potential therapeutic target for CC.

miR-30b suppresses the progression of breast cancer through inhibition of the PI3K/Akt signaling pathway by targeting Derlin-1

Background

MicroRNAs (miRNAs) play an essential role in the initiation, progression and metastasis of breast cancer. It has been confirmed that miR-30b is involved in various cancers. However, the specific involvement of miR-30b on breast cancer metastasis remains unknown. In the current study, we aimed to investigate the role of miR-30b in the progression and metastasis of breast cancer in vitro.

Methods

We up-regulated the expression of miR-30b in breast cancer cell lines SKBR3 and MDA-MB-231 by transfecting pCMV-miR-30b vector. CCK8, colony formation, Transwell, and flow cytometry assays were used to examine cell proliferation, migration, invasion and apoptosis, respectively. A dual-luciferase reporter assay was performed to identify the relationship between miR-30b and the target gene. Western blot assay was used to detect related proteins.

Results

Our data showed that the overexpression of miR-30b significantly inhibited proliferation, migration and invasion abilities in SKBR3 and MDA-MB-231 cells. Meanwhile, overexpression of miR-30b induced cell apoptosis for both SKBR3 and MDA-MB-231 cells by regulating the expression of apoptosis-related proteins (Bcl-2, Bax, active Caspase-3, and Caspase-9). Moreover, miR-30b inhibited the activation of the PI3K/Akt signaling pathway by decreasing the phosphorylation levels of Akt and mTOR. Furthermore, we determined that miR-30b could down-regulate the expression of Derlin-1 in a post-transcriptional manner by employing the dual-luciferase reporter and western blot assays. Further analysis demonstrated that depletion of Derlin-1 inhibited Akt phosphorylation, and Derlin-1 could restore the effect of miR-30b on Akt. In addition, the CCK8 assay showed that Derlin-1 could partly reverse the inhibition of cell proliferation of SKBR3 and MDA-MB-231 cells mediated by miR-30b.

Conclusions

Our data demonstrated that miR-30b suppresses the progression and metastasis of breast cancer via inhibition of the PI3K/Akt signaling pathway by targeting Derlin-1 in vitro. This suggests that miR-30b might be a novel potent target for breast cancer therapy.

Integrative analysis to identify oncogenic gene expression changes associated with copy number variations of enhancer in ovarian cancer

Enhancers are short regulatory regions (50-1500 bp) of DNA that control the tissue-specific activation of gene expression by long distance interaction with targeting gene regions. Recently, genome-wide identification of enhancers in diverse tissues and cell lines was achieved using high-throughput sequencing. Enhancers have been associated with malfunctions in cancer development resulting from point mutations in regulatory regions. However, the potential impact of copy number variations (CNVs) on enhancer regions is unknown. To learn more about the relationship between enhancers and cancer, we integrated the CNVs data on enhancers and explored their targeting gene expression pattern in high-grade ovarian cancer. Using human enhancer-gene interaction data with 13,691 interaction pairs between 7,905 enhancers and 5,297 targeting genes, we found that the 2,910 copy number gain events of enhancer are significantly correlated with the up-regulation of targeting genes. We further identified that a number of highly mutated super-enhancers, with concordant gene expression change on their targeting genes. We also identified 18 targeting genes by super-enhancers with prognostic significance for ovarian cancer, such as the tumour suppressor CDKN1B. We are the first to report that abundant copy number variations on enhancers could change the expression of their targeting genes which would be valuable for the design of enhancer-based cancer treatment strategy.

Derlin-1 overexpression confers poor prognosis in muscle invasive bladder cancer and contributes to chemoresistance and invasion through PI3K/AKT and ERK/MMP signaling

Derlin-1 has been found to be overexpressed in several human cancers. However, its clinical significance and biological roles in bladder cancer remain unexplored. Here, we found that Derlin-1 was upregulated in 38.6% (58/150) cases of cancer samples. The rate of Derlin-1 overexpression was higher in muscle invasive bladder cancer (MIBC) than non-muscle invasive bladder cancer (NMIBC) (p=0.0079). Derlin-1 was a predicting factor for poor patient prognosis. Derlin-1 depletion inhibited while its overexpression facilitated cell invasion and colony formation. In addition, Derlin-1 overexpression induced cisplatin resistance while its depletion sensitized cancer cells to cisplatin. Further analysis demonstrated that Derlin-1 activated AKT phosphorylation and upregulated Bcl-2 expression. Blockage of AKT signaling by LY294005 abolished the effects of Derlin-1 on Bcl-2 and cisplatin resistance. Immunoprecipitation indicated Derlin-1 interacted with p110α subunit of PI3K. In addition, we showed that Derlin-1 depletion downregulated and its overexpression upregulated cell MMP-2/9 expression and ERK phosphorylation. Derlin-1 mediated upregulation of MMP-2/9 could be blocked by ERK inhibitor. In conclusion, our study demonstrated that Derlin-1 is overexpressed in bladder cancer and promotes malignant phenotype through ERK/MMP and PI3K/AKT/Bcl-2 signaling pathway.

Elevated expression of Derlin-1 associates with unfavorable survival time of squamous cell carcinoma of the head and neck and promotes its malignance

Derlin-1 is over-expressed to function as an oncoprotein in breast, lung and colon cancers. However, the implications of Derlin-1 involved in squamous cell carcinoma of the head and neck (SCCHN) remain unknown. This study aims to investigate the effects of Derlin-1 expression on SCCHN tissues and cells. The potential mechanism of Derlin-1 regulating SCCHN cell proliferation, apoptosis and metastasis was also indicated in this work. Western blot and immunohistochemistry (IHC) assays showed that Derlin-1 was over-expressed in 114 SCCHN samples and five SCCHN cell lines. We found that the expression of Derlin-1 was positively associated with lymph node metastasis, clinical stage and recurrence in our SCCHN patients' samples. Survival analysis indicated that high expression of Derlin-1 was significantly associated with shorter overall survival (OS) and disease-free survival (DFS). Knock down expression of Derlin-1 in SCCHN cell lines was found to inhibit cell proliferation, metastasis and promote cell apoptosis. Further experiments showed that signals of PI3K/Akt, p53 and Smad2/3 may involve in these processes. In all, Derlin-1 might be a novel prognostic marker of SCCHN patients and plays an oncogenic role in SCCHN cell progression.

Overexpression of Derlin 3 is associated with malignant phenotype of breast cancer cells

Breast cancer (BC) is the most common malignant tumor among women worldwide. Development of novel molecular targets is important to improve prognosis of BC patients. Derlin 3 (DERL3) gene is a member of derlin family, and its coding protein is critical to the endoplasmic reticulum-associated degradation mechanism. However, its oncological role in breast cancer remains unclear. This study evaluated DERL3 expression and function in BC. We analyzed DERL3 mRNA in 13 BC and two non-cancerous cell lines, and explored effects of DERL3 knockdown on BC proliferation, invasion and migration. We also evaluated correlation of DERL3 mRNA expression levels with clinicopathological factors and prognosis in 167 BC patients. DERL3 mRNA expression was detected in five (38%) BC cell lines. Inhibiting DERL3 expression significantly decreased proliferation and invasion in BC cells. Specimens from patients with lymph node metastasis had higher DERL3 mRNA expression than those without (P=0.030). Patients in the highest quartile for DERL3 mRNA expression (n=42) were more likely to experience shorter overall survival than other patients (P=0.032). These findings indicate that DERL3 promotes malignant phenotype in BC cells. DERL3 may serve as a potential prognostic marker and therapeutic target for BC.

Derlin-1 is a target to improve radiotherapy effect of esophageal squamous cell carcinoma

Radiotherapy is widely used for treatment of esophageal squamous cell carcinoma (ESCC). This study aimed to explore the role of Derlin-1 on the sensitivity of ESCC to radiotherapy and its underlying mechanism. We examined the clinical significance of Derlin-1 in 125 ESCC tissues. We found that Derlin-1 protein was higher in ESCC tissues than that in normal esophageal epithelial tissues. Derlin-1 overexpression was correlated with chemoradiotherapy resistance in ESCC patients and served an independent predictor for short overall survival. siRNA knockdown and plasmid transfection were carried out in ESCC cell lines. Derlin-1 depletion inhibited cell growth while its overexpression facilitated cell growth. Derlin-1 overexpression in Eca-109 cells dramatically enhanced its resistance to radiotherapy with decreased apoptosis rate. On the contrary, Derlin-1 depletion in TE-1 cell line showed the opposite effects. In addition, radioresistance conferred by Derlin-1 was attributed to its role of activating AKT/Bcl-2 signaling pathway and reducing caspase3 cleavage. Blockage of AKT signaling attenuated the role of Derlin-1 on radioresistance. Furthermore, Derlin-1 could interact with PI3K p110α in ESCC cell lines. Taken together, Our data demonstrate that Derlin-1 overexpression predicts poor prognosis and protects ESCC from irradiation induced apoptosis through PI3K/AKT/Bcl-2 signaling pathway. Derlin-1 may serve as a novel predictor for radiosentivity and a molecular target for ESCC.

TTBK2 circular RNA promotes glioma malignancy by regulating miR-217/HNF1β/Derlin-1 pathway

BACKGROUND

Circular RNAs are a subgroup of non-coding RNAs and generated by a mammalian genome. Herein, the expression and function of circular RNA circ-TTBK2 were investigated in human glioma cells.

METHODS

Fluorescence in situ hybridization and quantitative real-time PCR were conducted to profile the cell distribution and expression of circ-TTBK2 and microRNA-217 (miR-217) in glioma tissues and cells. Immunohistochemical and western blot were used to determine the expression of HNF1β and Derlin-1 in glioma tissues and cells. Stable knockdown of circ-TTBK2 or overexpression of miR-217 glioma cell lines (U87 and U251) were established to explore the function of circ-TTBK2 and miR-217 in glioma cells. Further, luciferase reports and RNA immunoprecipitation were used to investigate the correlation between circ-TTBK2 and miR-217. Cell Counting Kit-8, transwell assays, and flow cytometry were used to investigate circ-TTBK2 and miR-217 function including cell proliferation, migration and invasion, and apoptosis, respectively. ChIP assays were used to ascertain the correlations between HNF1β and Derlin-1.

RESULTS

We found that circ-TTBK2 was upregulated in glioma tissues and cell lines, while linear TTBK2 was not dysregulated in glioma tissues and cells. Enhanced expression of circ-TTBK2 promoted cell proliferation, migration, and invasion, while inhibited apoptosis. MiR-217 was downregulated in glioma tissues and cell lines. We also found that circ-TTBK2, but not linear TTBK2, acted as miR-217 sponge in a sequence-specific manner. In addition, upregulated circ-TTBK2 decreased miR-217 expression and there was a reciprocal negative feedback between them in an Argonaute2-dependent manner. Moreover, reintroduction of miR-217 significantly reversed circ-TTBK2-mediated promotion of glioma progression. HNF1β was a direct target of miR-217, and played oncogenic role in glioma cells. Remarkably, circ-TTBK2 knockdown combined with miR-217 overexpression led to tumor regression in vivo.

CONCLUSIONS

These results demonstrated a novel role circ-TTBK2 in the glioma progression.

High Expression of Derlin-1 Is Associated with the Malignancy of Bladder Cancer in a Chinese Han Population

Derlin-1 is overexpressed in various types of solid tumors and has an important function in cancer progression. However, its expression pattern in and association with the clinicopathological characteristics of human bladder cancer remain unclear. In the present study, 3 pairs of fresh samples of bladder cancer tissue and paracancerous tissue were first detected by liquid chromatography tandem mass spectrometry (UPLC-MS/MS) to screen for differentially expressed proteins. Following bioinformatics analysis and assessments by qRT-PCR and western blotting, Derlin-1 was selected as a candidate protein and was then validated in samples from patients with bladder cancer by immunohistochemistry and western blotting. The results showed that the bladder cancer tissues exhibited higher levels of Derlin-1 expression than the paracancerous tissues (P < 0.05). Positive expression of Derlin-1 was significantly correlated with tumor stage, histological grade, and lymph node metastasis (P < 0.001) but was not correlated with other clinicopathological parameters including patient age (P = 0.758) and gender (P = 0.831). Besides, Derlin-1 was highly expressed in BC cell lines (um-uc-3 and T24), and the interference of Derlin-1 could reverse EMT progression, inhibit the tumor migration and invasion in T24 cells. Further, patients with positive Derlin-1 expression had shorter overall survival than those with negative expression (P < 0.001). Taken together, our results demonstrated that Derlin-1 was overexpressed in bladder cancer and was associated with the malignancy of bladder cancer.

Derlin-1 is overexpressed in human colon cancer and promotes cancer cell proliferation

Derlin-1 is overexpressed in many types of solid tumors and plays an important role in cancer progression. However, the expression pattern and functions of Derlin-1 in human colon cancer are not fully understood. In the present study, we examined Derlin-1 expression in colon cancer cell lines and human tissues and investigated its role in colon cancer. We found that Derlin-1 expression was increased significantly in colon cancer tissues and its overexpression correlated with the tumor differentiation, Dukes stage, invasion, lymph node metastasis, distant metastasis, and poor overall survival. The silencing of Derlin-1 by shRNA led to the growth inhibition of colon cancer cells, which were associated with the promotion of apoptosis. Furthermore, Derlin-1 silencing significantly inhibited the activation of the PI3K/AKT signaling pathway. Taken together, our results showed that Derlin-1 is overexpressed in colon cancer and promotes proliferation of colon cancer cells. Derlin-1 may be a potential therapeutic target for the treatment of colon cancer.

Immortalization of epithelial cells in oral carcinogenesis as revealed by genome-wide array comparative genomic hybridization: A meta-analysis

BACKGROUND

This purpose of this meta-analysis study was to identify the most frequent and potentially significant copy number alteration (CNA) in oral carcinogenesis.

METHODS

Seven oral squamous cell carcinoma (OSCC)-related publications, corresponding to 312 samples, were identified for this meta-analysis. The data were analyzed in a 4-step process that included the genome assembly coordination of multiple platforms, assignment of chromosomal position anchors, calling gains and losses, and functional annotation analysis.

RESULTS

Gains were more frequent than losses in the entire dataset. High-frequency gains were identified in chromosomes 5p, 14q, 11q, 7p, 17q, 20q, 8q, and 3q, whereas high-frequency losses were identified in chromosomes 3p, 8p, 6p, 18q, and 4q. Ingenuity pathway analysis showed that the top biological function was associated with immortalization of the epithelial cells (p = 1.93E-04).

CONCLUSION

This study has identified multiple recurrent CNAs that are involved in various biological annotations associated with oral carcinogenesis. © 2015 Wiley Periodicals, Inc. Head Neck 38: E783-E797, 2016.

Determination of the protein expression profiles of breast cancer cell lines by quantitative proteomics using iTRAQ labelling and tandem mass spectrometry

Breast cancer is the principal cancer in women worldwide. Although there are serum tumor markers such as CEA and HER2, they are detected in advanced stages of the disease and used as progression and recurrence markers. Therefore, there is a necessity for the identification of new markers that might lead to an early detection and also provide evidence of an effective treatment. The aim of this work was to determine the differential protein expression profiles of four breast cancer cell lines in comparison to a normal control cell line by iTRAQ labelling and tandem mass spectrometry, in order to identify putative biomarkers of the disease. We identified 1,020 iTRAQ-labelled polypeptides with at least one peptide identified with more than 95% in confidence. Overexpressed polypeptides in all cancer cell lines were 78, whilst the subexpressed were 128. We categorised them with PANTHER program into biological processes, being the metabolic pathways the most affected. We detected six groups of proteins with the STRING program involved in DNA topology, glycolysis, translation initiation, splicing, pentose pathway, and proteasome degradation. The main subexpressed protein network included mitochondrial proteins involved in oxidative phosphorylation. We propose BAG6, DDX39, ANXA8 and COX4 as putative biomarkers in breast cancer.

BIOLOGICAL SIGNIFICANCE

We report a set of differentially expressed proteins in the MCF7 and T47D (Luminal A), MDA-MB-231 (Claudin low) and SK-BR-3 (HER2(+)) breast cancer cell lines that have not been previously reported in breast cancer disease. From these proteins, we propose BAG6, DDX39, ANXA8 and COX4 as putative biomarkers in breast cancer. On the other hand, we propose sets of unique polypeptides in each breast cancer cell line that can be useful in the classification of different subtypes of breast cancer.

Expression of Derlin-1 and its effect on expression of autophagy marker genes under endoplasmic reticulum stress in lung cancer cells

Background

Recent findings indicated that Derlin-1 has an important function in tumour progression. In this study, we aimed to determine whether Derlin-1 has an oncogene function as a cross-talk molecule with autophagy.

Methods

Cancer cells were treated with tunicamycin (TM) for 8 and 24 h. The expression of Derlin-1 and autophagy-related genes was determined by western blot. Autophagy was analysed by fluorescence microscopy after staining the cancer cells with monodansylcadaverine. The interaction between Derlin-1 and other proteins was identified using co-immunoprecipitation assay.

Results

Our study demonstrated high Derlin-1 expression levels in most non-small lung cancer cell lines. Derlin-1 expression was enhanced under endoplasmic reticulum (ER) stress. Previous studies revealed that TM triggers the initiation of autophagy by activating Beclin 1, converting LC3I to LC3II and degrading p62. Knockdown of Derlin-1 did not affect Beclin 1 and LC3II expression but disrupted the degradation of p62 under ER stress, which resulted in the blockage of autophagy flux. Furthermore, Derlin-1 and p62 were observed to interact under ER stress.

Conclusion

This study is the first report about the interaction between Derlin-1 and p62. Derlin-1 may function in tumour progression partially by interacting with p62.

Integrated genomic and epigenomic analysis of breast cancer brain metastasis

The brain is a common site of metastatic disease in patients with breast cancer, which has few therapeutic options and dismal outcomes. The purpose of our study was to identify common and rare events that underlie breast cancer brain metastasis. We performed deep genomic profiling, which integrated gene copy number, gene expression and DNA methylation datasets on a collection of breast brain metastases. We identified frequent large chromosomal gains in 1q, 5p, 8q, 11q, and 20q and frequent broad-level deletions involving 8p, 17p, 21p and Xq. Frequently amplified and overexpressed genes included ATAD2, BRAF, DERL1, DNMTRB and NEK2A. The ATM, CRYAB and HSPB2 genes were commonly deleted and underexpressed. Knowledge mining revealed enrichment in cell cycle and G2/M transition pathways, which contained AURKA, AURKB and FOXM1. Using the PAM50 breast cancer intrinsic classifier, Luminal B, Her2+/ER negative, and basal-like tumors were identified as the most commonly represented breast cancer subtypes in our brain metastasis cohort. While overall methylation levels were increased in breast cancer brain metastasis, basal-like brain metastases were associated with significantly lower levels of methylation. Integrating DNA methylation data with gene expression revealed defects in cell migration and adhesion due to hypermethylation and downregulation of PENK, EDN3, and ITGAM. Hypomethylation and upregulation of KRT8 likely affects adhesion and permeability. Genomic and epigenomic profiling of breast brain metastasis has provided insight into the somatic events underlying this disease, which have potential in forming the basis of future therapeutic strategies.

Simultaneous structure-activity studies and arming of natural products by C-H amination reveal cellular targets of eupalmerin acetate

Natural products have a venerable history of, and enduring potential for the discovery of useful biological activity. To fully exploit this, the development of chemical methodology that can functionalize unique sites within these complex structures is highly desirable. Here, we describe the use of rhodium(II)-catalysed C-H amination reactions developed by Du Bois to carry out simultaneous structure-activity relationship studies and arming (alkynylation) of natural products at 'unfunctionalized' positions. Allylic and benzylic C-H bonds in the natural products undergo amination while olefins undergo aziridination, and tertiary amine-containing natural products are converted to amidines by a C-H amination-oxidation sequence or to hydrazine sulfamate zwitterions by an unusual N-amination. The alkynylated derivatives are ready for conversion into cellular probes that can be used for mechanism-of-action studies. Chemo- and site-selectivity was studied with a diverse library of natural products. For one of these-the marine-derived anticancer diterpene, eupalmerin acetate-quantitative proteome profiling led to the identification of several protein targets in HL-60 cells, suggesting a polypharmacological mode of action.

Derlin-1 is overexpressed in non-small cell lung cancer and promotes cancer cell invasion via EGFR-ERK-mediated up-regulation of MMP-2 and MMP-9

Previous studies indicated a role of Derlin-1 in human cancers; however, its expression pattern in non-small cell lung cancer (NSCLC) and the molecular mechanism of Derlin-1 on cancer progression have not been characterized. In the present study, Derlin-1 expression was examined in lung cancer cell lines and human tissues. Derlin-1 overexpression correlated with pTNM stage, lymph node metastasis, and poor overall survival. siRNA knockdown of Derlin-1 impaired anchorage-dependent and anchorage-independent cell growth and invasion in A549 and H1299 cell lines, and its overexpression promoted proliferation and invasion in HBE and LTE cell lines. Derlin-1 depletion decreased matrix metalloproteinase (MMP)-2/9 at both protein and mRNA levels, with decreased MAP kinase/extracellular signal-regulated kinase (ERK)/ERK phosphorylation. Derlin-1 overexpression up-regulated MMP-2/9 expression and ERK phosphorylation, which could be reversed by MAP kinase/ERK kinase inhibitor, PD98059. The effect of Derlin-1 on MMP-2/9 up-regulation was abolished in ERK1/2 siRNA-treated cells. Further analysis showed that Derlin-1 overexpression induced EGFR phosphorylation. EGFR inhibitor blocked Derlin-1-mediated up-regulation of EGFR and ERK phosphorylation. MMP-2/9 and p-ERK up-regulation by Derlin-1 was partly blocked in EGFR-depleted cells with siRNA treatment. Immunoprecipitation confirmed the association between Derlin-1 and EGFR. In summary, our results showed that Derlin-1 is overexpressed in NSCLC and promotes invasion by EGFR-ERK-mediated up-regulation of MMP-2 and MMP-9. Derlin-1 may serve as a therapeutic target for NSCLC.

SEL1L, an UPR response protein, a potential marker of colonic cell transformation

BACKGROUND

SEL1L gene product is implicated in the endoplasmic reticulum (ER)-associated protein degradation and Unfolded Protein Response pathways. This gene and associated miRNAs have been indicated as predictive and prognostic markers of pancreatic cancer.

AIM

Explore the role of SEL1L in colorectal cancer (CRC) progression.

METHODS

SEL1L expression was analysed immunohistochemically in 153 adenomas and 71 CRCs from African American and North Italian patients. The distribution of stained cells was determined by computing median and inter quartile range. The receiver operating characteristics plot was used as discriminate power of SEL1L expression, CRC diagnosis and the effects on patient survival.

RESULTS

SEL1L was low in normal mucosa and confined to few scattered cells at the base crypt of the villi and in the foveolar glandular compartment. The highest levels were in Paneth cells within the lysosomes. The enterocytic progenitor cells and mature enterocytes showed less cytoplasmic staining. In CRCs, SEL1L expression significantly correlated with the progression from adenoma to carcinoma (P = 0.0001) being stronger in well-to-moderately differentiated cancers. No correlation was found with other clinicopathological characteristics or ethnicity.

CONCLUSIONS

SEL1L expression is a potential CRC tissue biomarker since its expression is significantly higher in adenoma cells with respect to normal mucosa. The levels of expression decrease sensibly in undifferentiated CRC cancers. Interestingly, Paneth cells contain high levels of SEL1L protein that could indicate pre-neoplastic mucosa undergoing neoplastic transformation. Since SEL1L's major function lies within ER stress and active ERAD response, it may identify CRCs with differentiated secretory phenotype and acute cellular stress.

Role of Derlin-1 protein in proteostasis regulation of ATP-sensitive potassium channels

ATP-sensitive potassium (K(ATP)) channels composed of sulfonylurea receptor 1 (SUR1) and Kir6.2 regulate insulin secretion by linking glucose metabolism with membrane potential. The number of K(ATP) channels in the plasma membrane affects the sensitivity of β-cells to glucose. Aberrant surface channel expression leads to insulin secretion disease. Previously, we have shown that K(ATP) channel proteins undergo endoplasmic reticulum (ER)-associated degradation (ERAD) via the ubiquitin-proteasome pathway, and inhibition of proteasome function results in an increase in channel surface expression. Here, we investigated whether Derlin-1, a protein involved in retrotranslocation of misfolded or misassembled proteins across the ER membrane for degradation by cytosolic proteasomes, plays a role in ERAD and, in turn, biogenesis efficiency of K(ATP) channels. We show that both SUR1 and Kir6.2 form a complex with Derlin-1 and an associated AAA-ATPase, p97. Overexpression of Derlin-1 led to a decrease in the biogenesis efficiency and surface expression of K(ATP) channels. Conversely, knockdown of Derlin-1 by RNA interference resulted in increased processing of SUR1 and a corresponding increase in surface expression of K(ATP) channels. Importantly, knockdown of Derlin-1 increased the abundance of disease-causing misfolded SUR1 or Kir6.2 proteins and even partially rescued surface expression in a mutant channel. We conclude that Derlin-1, by being involved in ERAD of SUR1 and Kir6.2, has a role in modulating the biogenesis efficiency and surface expression of K(ATP) channels. The results suggest that physiological or pathological changes in Derlin-1 expression levels may affect glucose-stimulated insulin secretion by altering surface expression of K(ATP) channels.

Tumor suppressor genes FHIT and WWOX are deleted in primary effusion lymphoma (PEL) cell lines

Primary effusion lymphoma (PEL) is a diffuse-large B-cell lymphoma with poor prognosis. One hundred percent of PELs carry the genome of Kaposi sarcoma-associated herpesvirus and a majority are coinfected with Epstein-Barr virus (EBV). We profiled genomic aberrations in PEL cells using the Affymetrix 6.0 SNP array. This identified for the first time individual genes that are altered in PEL cells. Eleven of 13 samples (85%) were deleted for the fragile site tumor suppressors WWOX and FHIT. Alterations were also observed in the DERL1, ETV1, RASA4, TPK1, TRIM56, and VPS41 genes, which are yet to be characterized for their roles in cancer. Coinfection with EBV was associated with significantly fewer gross genomic aberrations, and PEL could be segregated into EBV-positive and EBV-negative clusters on the basis of host chromosome alterations. This suggests a model in which both host genetic aberrations and the 2 viruses contribute to the PEL phenotype.

Molecular characterization and expression of DERL1 in bovine ovarian follicles and corpora lutea

The endoplasmic reticulum (ER) is a major site of protein synthesis and facilitates the folding and assembly of newly synthesized proteins. Misfolded proteins are retrotranslocated across the ER membrane and destroyed at the proteasome. DERL1 is an important protein involved in the retrotranslocation and degradation of a subset of misfolded proteins from the ER. We characterized a 2617 bp cDNA from bovine granulosa cells that corresponded to bovine DERL1. Two transcripts of 3 and 2.6 kb were detected by Northern blot analysis, and showed variations in expression among tissues. During follicular development, DERL1 expression was greater in day 5 dominant follicles compared to small follicles, ovulatory follicles, or corpus luteum (CL). Within the CL, DERL1 mRNA expression was intermediate in midcycle, and lowest in late cycle as compared to early in the estrous cycle. Western blot analyses demonstrated the presence of DERL1 in the bovine CL at days 5, 11, and 18 of the estrous cycle. Co-immunoprecipitation using luteal tissues showed that DERL1 interacts with class I MHC but not with VIMP or p97 ATPase. The interaction between DERL1 and MHC I suggests that, in the CL, DERL1 may regulate the integrity of MHC I molecules that are transported to the ER membrane. Furthermore, the greater expression of DERL1 mRNA is associated with the active follicular development and early luteal stages, suggesting a role of DERL1 in tissue remodeling events and maintenance of function in reproductive tissues.

Identification of candidate growth promoting genes in ovarian cancer through integrated copy number and expression analysis

Ovarian cancer is a disease characterised by complex genomic rearrangements but the majority of the genes that are the target of these alterations remain unidentified. Cataloguing these target genes will provide useful insights into the disease etiology and may provide an opportunity to develop novel diagnostic and therapeutic interventions. High resolution genome wide copy number and matching expression data from 68 primary epithelial ovarian carcinomas of various histotypes was integrated to identify genes in regions of most frequent amplification with the strongest correlation with expression and copy number. Regions on chromosomes 3, 7, 8, and 20 were most frequently increased in copy number (>40% of samples). Within these regions, 703/1370 (51%) unique gene expression probesets were differentially expressed when samples with gain were compared to samples without gain. 30% of these differentially expressed probesets also showed a strong positive correlation (r≥0.6) between expression and copy number. We also identified 21 regions of high amplitude copy number gain, in which 32 known protein coding genes showed a strong positive correlation between expression and copy number. Overall, our data validates previously known ovarian cancer genes, such as ERBB2, and also identified novel potential drivers such as MYNN, PUF60 and TPX2.

The Combined Expression Pattern of BMP2, LTBP4, and DERL1 Discriminates Malignant From Benign Canine Mammary Tumors

Several markers of malignancy have been proposed for canine mammary tumors on the mRNA and protein levels. However, their association with tumor malignancy applies only for mean values of large groups of tumors, but no single marker identified to date can be used to reliably predict malignancy for individual tumors. A quantitative real-time reverse transcription polymerase chain reaction array was established to quantify the expression levels of 49 genes relevant to carcinogenesis in laser-microdissected tumor cells of 10 benign and 13 metastatic canine mammary tumors. Analysis of variance and discriminant analysis were used to identify relevant gene expression patterns that differentiate adenomas from metastatic carcinomas and their lymph node metastases. Seventeen genes with significant ( P < .05) differences in gene expression levels between benign and malignant tumors were identified—including ERBB1, SLIT2, progesterone receptor, MIG6, SATB1, and SMAD6—but correct classification of each tumor as benign or malignant was impossible on the basis of any of these genes alone. However, the combined expression patterns of BMP2, LTBP4, and DERL1 (Derlin-1) correctly classified each individual tumor as benign or malignant. This pilot study identified a complex mRNA expression pattern of 3 genes that was able to identify malignancy in laser-microdissected tumor cells for each individual tumor, instead of group means as used in previous studies.

Reciprocal changes in gene expression profiles of cocultured breast epithelial cells and primary fibroblasts

The importance of epithelial-stroma interaction in normal breast development and tumor progression has been recognized. To identify genes that were regulated by these reciprocal interactions, we cocultured a nonmalignant (MCF10A) and a breast cancer derived (MDA-MB231) basal cell lines, with fibroblasts isolated from breast benign-disease adjacent tissues (NAF) or with carcinoma-associated fibroblasts (CAF), in a transwell system. Gene expression profiles of each coculture pair were compared with the correspondent monocultures, using a customized microarray. Contrariwise to large alterations in epithelial cells genomic profiles, fibroblasts were less affected. In MDA-MB231 highly represented genes downregulated by CAF derived factors coded for proteins important for the specificity of vectorial transport between ER and golgi, possibly affecting cell polarity whereas the response of MCF10A comprised an induction of genes coding for stress responsive proteins, representing a prosurvival effect. While NAF downregulated genes encoding proteins associated to glycolipid and fatty acid biosynthesis in MDA-MB231, potentially affecting membrane biogenesis, in MCF10A, genes critical for growth control and adhesion were altered. NAFs responded to coculture with MDA-MB231 by a decrease in the expression of genes induced by TGFbeta1 and associated to motility. However, there was little change in NAFs gene expression profile influenced by MCF10A. CAFs responded to the presence of both epithelial cells inducing genes implicated in cell proliferation. Our data indicate that interactions between breast fibroblasts and basal epithelial cells resulted in alterations in the genomic profiles of both cell types which may help to clarify some aspects of this heterotypic signaling.

Implications of endoplasmic reticulum stress, the unfolded protein response and apoptosis for molecular cancer therapy. Part I: targeting p53, Mdm2, GADD153/CHOP, GRP78/BiP and heat shock proteins

BACKGROUND

In eukaryotes, endoplasmic reticulum stress (ERS) and the unfolded protein response (UPR) are coordinately regulated to maintain steady-state levels and activities of various cellular proteins to ensure cell survival.

OBJECTIVE

This review (Part I of II) focuses on specific ERS and UPR signalling regulators, their expression in the cancer phenotype and apoptosis, and proposes how their implication in these processes can be rationalised into proteasome inhibition, apoptosis induction and the development of more efficacious targeted molecular cancer therapies.

METHOD

In this review, we contextualise many ERS and UPR client proteins that are deregulated or mutated in cancers and show links between ERS and the UPR, their implication in oncogenic transformation, tumour progression and escape from immune surveillance, apoptosis inhibition, angiogenesis, metastasis, acquired drug resistance and poor cancer prognosis.

CONCLUSION

Evasion of programmed cell death or apoptosis is a hallmark of cancer that enables tumour cells to proliferate uncontrollably. Successful eradication of cancer cells through targeting ERS- and UPR-associated proteins to induce apoptosis is currently being pursued as a central tenet of anticancer drug discovery.

Derlin-1 and stanniocalcin-1 are differentially regulated in metastasizing canine mammary adenocarcinomas

Derlin-1, stanniocalcin-1, epithelial glycoprotein-2 (EGP-2) and maspin are associated with the metastasis of human breast cancer cells. This study reports the potential role of these molecules in metastasis of canine mammary tumours. Laser microdissected tissue samples were prepared from normal canine mammary gland and from simple adenomas, adenocarcinomas and their lymph node metastases. The expression of genes encoding the molecules of interest in these tissues was determined by real-time quantitative reverse transcriptase polymerase chain reaction (RT-PCR). Most adenomas displayed reduced expression of derlin-1 mRNA. Few adenocarcinomas overexpressed derlin-1 mRNA, but all lymph node metastases overexpressed this gene product. Stanniocalcin-1 mRNA was not expressed within adenomas and was reduced in adenocarcinomas and their lymph node metastases. EGP-2 gene expression did not differ between normal, benign and malignant neoplastic tissues. Maspin gene expression varied markedly among the tumours with reduced or increased expression compared with normal mammary gland. Taken together, these results suggest that malignant behaviour of canine mammary adenocarcinoma is associated with reduced transcription of the stanniocalcin-1 gene and overexpression of the derlin-1 gene.

Derlin-1 is overexpressed on the tumor cell surface and enables antibody-mediated tumor targeting therapy

PURPOSE

Tumor targeting therapy is one of the most promising strategies for anticancer treatment. Derlin-1 has been reported to participate in misfolded protein dislocation and integrates into the endoplasmic reticulum (ER) membrane to survey for such protein aggregates. We elucidate herein that Derlin-1 can leak to the plasmalemma from the ER in tumor cells and may have clinical application as a novel cancer target in the hope of developing a new tumor targeting therapy.

EXPERIMENTAL DESIGN

The cell surface expression of Derlin-1 was shown by immunofluorescence analysis of nonpermeabilized cells and Western blotting of fractional proteins of tumor cells. Derlin-1 expression in cancerous tissues was also shown by immunohistochemistry. Biodistribution analysis and gamma-scintigraphic imaging were done using (125)I-labeled Derlin-1 targeting antibody in isogenic mice models. Finally, tumor-bearing mice were treated by the anti-Derlin-1 polyclonal antibody and monoclonal antibodies.

RESULTS

Derlin-1 was expressed on various tumor cell surfaces and adopted a homodimer conformation. Robust cytoplasmic and membrane expression of Derlin-1 was detected in various types of human cancers tissues but was not correlated with any clinicopathologic features of pancreatic cancer. Derlin-1 directed antibodies specifically targeted to colon tumors and significantly suppress tumor growth in isogenic mice.

CONCLUSIONS

These preclinical data show that Derlin-1 protein is a functional molecular target expressed on the tumor cell surface and is a candidate therapeutic target that may be translated into clinical applications.