Immunohistochemical Expression of DCUN1D1 in Non-small Cell Lung Carcinoma: Its Relation to Brain Metastasis

A comprehensive review on DCN1 protein, inhibitors and their therapeutic applications

DCN1, a critical co-E3 ligase in the neddylation process, mediates the activation of Cullin-RING Ligases (CRLs) by selectively catalyzing cullin neddylation, further regulating the activity of substrate proteins. It has been identified as an important target for human diseases, including cancers, fibrotic diseases, and cardiovascular disorders. This work aims to provide a perspective for the discovery of novel DCN1 inhibitors by the analysis of biological roles, protein structures, structure-activity relationships and design strategy disclosed in recent years. Additionally, we will discuss the current status, challenges and opportunities in hope of offering insights into the development of DCN1 inhibitors for human diseases.

DCUN1D1 and neddylation: Potential targets for cancer therapy

Cancer affects millions of people and understanding the molecular mechanisms related to disease development and progression is essential to manage the disease. Post-translational modification (PTM) processes such as ubiquitination and neddylation have a significant role in cancer development and progression by regulating protein stability, function, and interaction with other biomolecules. Both ubiquitination and neddylation are analogous processes that involves a series of enzymatic steps leading to the covalent attachment of ubiquitin or NEDD8 to target proteins. Neddylation modifies the CRL family of E3 ligase and regulates target proteins' function and stability. The DCUN1D1 protein is a regulator of protein neddylation and ubiquitination and acts promoting the neddylation of the cullin family components of E3-CRL complexes and is known to be upregulated in several types of cancers. In this review we compare the PTM ubiquitination and neddylation. Our discussion is focused on the neddylation process and the role of DCUN1D1 protein in cancer development. Furthermore, we provide describe DCUN1D1 protein and discuss its role in pathogenesis and signalling pathway in six different types of cancer. Additionally, we explore both the neddylation and DCUN1D1 pathways as potential druggable targets for therapeutic interventions. We focus our analysis on the development of compounds that target specifically neddylation or DCUN1D1. Finally, we provide a critical analysis about the challenges and perspectives in the field of DCUN1D1 and neddylation in cancer research. KEY POINTS: Neddylation is a post-translational modification that regulates target proteins' function and stability. One regulator of the neddylation process is a protein named DCUN1D1 and it is known to have its expression deregulated in several types of cancers. Here, we provide a detailed description of DCUN1D1 structure and its consequence for the development of cancer. We discuss both the neddylation and DCUN1D1 pathways as potential druggable targets for therapeutic interventions and provide a critical analysis about the challenges and perspectives in the field of DCUN1D1 and neddylation in cancer research.

YY1 mediated DCUN1D5 transcriptional activation promotes triple-negative breast cancer progression by targeting FN1/PI3K/AKT pathway

Triple-negative breast cancer (TNBC) is more aggressive and has a higher metastasis rate compared with other subtypes of breast cancer. Due to the lack of drug-targetable receptors, chemotherapy is now the only available systemic treatment for TNBC. However, some patients might still develop drug resistance and have poor prognosis. Therefore, novel molecular biomarkers and new treatment targets are urgently needed for patients with TNBC. To provide molecular insights into TNBC progression, we investigated the function and the underlying mechanism of Defective in cullin neddylation 1 domain containing 5 (DCUN1D5) in the regulation of TNBC. By TCGA dataset and surgical specimens with immunohistochemical (IHC) staining method, DCUN1D5 was identified to be significantly upregulated in TNBC tumor tissues and negatively associated with prognosis. A series of in vitro and in vivo experiments were performed to confirm the oncogenic role of DCUN1D5 in TNBC. Overexpression of FN1 or PI3K/AKT activator IGF-1 could restore the proliferative and invasive ability induced by DCUN1D5 knockdown and DCUN1D5 could act as a novel transcriptional target of transcription factor Yin Yang 1 (YY1). In conclusion, YY1-enhanced DCUN1D5 expression could promote TNBC progression by FN1/PI3K/AKT pathway and DCUN1D5 might be a potential prognostic biomarker and therapeutic target for TNBC treatment.

Discovery of WS-384, a first-in-class dual LSD1 and DCN1-UBC12 protein-protein interaction inhibitor for the treatment of non-small cell lung cancer

Abnormally high expression of lysine-specific demethylase 1 A (LSD1) and DCN1 plays a vital role in the occurrence, development, and poor prognosis of non-small cell lung cancer (NSCLC). Accumulating evidence has shown that the development of small-molecule inhibitors dually targeting LSD1 and the DCN1-UBC12 interaction probably have therapeutic promise for cancer therapy. This work reported that WS-384 dually targeted LSD1 and DCN1-UBC12 interactions and evaluated its antitumor effects in vitro and in vivo. Specifically, WS-384 inhibited A549 and H1975 cells viability and decreased colony formation and EdU incorporation. WS-384 could also trigger cell cycle arrest, DNA damage, and apoptosis. Moreover, WS-384 significantly decreased tumor weight and volume in A549 xenograft mice. Mechanistically, WS-384 increased the gene and protein level of p21 by suppressing the neddylation of cullin 1 and decreasing H3K4 demethylation at the CDKN1A promoter. The synergetic upregulation of p21 contributed to cell cycle arrest and the proapoptotic effect of WS-384 in NSCLC cells. Taken together, our proof of concept studies demonstrated the therapeutic potential of dual inhibition of LSD1 and the DCN1-UBC12 interaction for the treatment of NSCLC. WS-384 could be used as a lead compound to develop new dual LSD1/DCN1 inhibitors for the treatment of human diseases in which LSD1 and DCN1 are dysregulated.

Research progress of LSD1-based dual-target agents for cancer therapy

Lysine-specific demethylase 1 (LSD1) is a histone lysine demethylase that is significantly overexpressed or dysregulated in different cancers and plays important roles in cell growth, invasion, migration, immune escape, angiogenesis, gene regulation, and transcription. Therefore, it is a superb target for the discovery of novel antitumor agents. However, because of their innate and acquired resistance and low selectivity, LSD1 inhibitors are associated with limited therapeutic efficacy and high toxicity. Furthermore, LSD1 inhibitors synergistically improve the efficacy of additional antitumor drugs, which encourages numerous medicinal chemists to innovate and develop new-generation LSD1-based dual-target agents. This review discusses the theoretical foundation of the design of LSD1-based dual-target agents and summarizes their possible applications in treating cancers.

Inhibition of DCUN1D1 attenuates periodontitis by suppressing NF-κB signaling

Nuclear factor kappa-B (NF-κB) signaling-mediated inflammation contributes greatly to the pathogenesis of periodontitis. Neddylation, a ubiquitin-like posttranslational modification, is known to regulate NF-κB signaling. DCUN1D1 (defective in cullin neddylation 1 domain containing 1) is a critical factor in neddylation and has been shown to regulate NF-κB activation. However, the previse roles of DCUN1D1 in periodontitis are not fully elucidated. To explore the roles of DCUN1D1 in periodontitis, the expression of DCUN1D1 was measured in gingival tissues of patients with periodontitis. We inhibited DCUN1D1 by siRNA knocking down or using inhibitor in gingival fibroblasts and the lipopolysaccharides (LPS)-induced expression of IL-6 and TNF-α, and activation of NF-κB were measured. The expression of DCUN1D1 was increased in gingival tissues of patients with periodontitis. Knocking down or inhibiting DCUN1D1 suppressed LPS-induced production of IL-6 and TNF-α, decreased NF-κB activity, and inhibited LPS-induced activation of NF-κB. Inhibiting DCUN1D1 ameliorates periodontitis by suppressing NF-κB signaling.

Targeting cullin neddylation for cancer and fibrotic diseases

Protein neddylation is a post-translational modification, and its best recognized substrates are cullin family proteins, which are the core component of Cullin-RING ligases (CRLs). Given that most neddylation pathway proteins are overactivated in different cancers and fibrotic diseases, targeting neddylation becomes an emerging approach for the treatment of these diseases. To date, numerous neddylation inhibitors have been developed, of which MLN4924 has entered phase I/II/III clinical trials for cancer treatment, such as acute myeloid leukemia, melanoma, lymphoma and solid tumors. Here, we systematically describe the structures and biological functions of the critical enzymes in neddylation, highlight the medicinal chemistry advances in the development of neddylation inhibitors and propose the perspectives concerning targeting neddylation for cancer and fibrotic diseases.

DCUN1D1 Is an Essential Regulator of Prostate Cancer Proliferation and Tumour Growth That Acts through Neddylation of Cullin 1, 3, 4A and 5 and Deregulation of Wnt/Catenin Pathway

Defective in cullin neddylation 1 domain containing 1 (DCUN1D1) is an E3 ligase for the neddylation, a post-translational process similar to and occurring in parallel to ubiquitin proteasome pathway. Although established as an oncogene in a variety of squamous cell carcinomas, the precise role of DCUN1D1 in prostate cancer (PCa) has not been previously explored thoroughly. Here, we investigated the role of DCUN1D1 in PCa and demonstrated that DCUN1D1 is upregulated in cell lines as well as human tissue samples. Inhibition of DCUN1D1 significantly reduced PCa cell proliferation and migration and remarkably inhibited xenograft formation in mice. Applying both genomics and proteomics approaches, we provide novel information about the DCUN1D1 mechanism of action. We identified CUL3, CUL4B, RBX1, CAND1 and RPS19 proteins as DCUN1D1 binding partners. Our analysis also revealed the dysregulation of genes associated with cellular growth and proliferation, developmental, cell death and cancer pathways and the WNT/β-catenin pathway as potential mechanisms. Inhibition of DCUN1D1 leads to the inactivation of β-catenin through its phosphorylation and degradation which inhibits the downstream action of β-catenin, reducing its interaction with Lef1 in the Lef1/TCF complex that regulates Wnt target gene expression. Together our data point to an essential role of the DCUN1D1 protein in PCa which can be explored for potential targeted therapy.

Identification of phytochemical compounds of Fagopyrum dibotrys and their targets by metabolomics, network pharmacology and molecular docking studies

Acute lung injury (ALI) is a clinically severe lung illness with high incidence rate and mortality. Especially, coronavirus disease 2019 (COVID-19) poses a serious threat to world wide governmental fitness. It has distributed to almost from corner to corner of the universe, and the situation in the prevention and control of COVID-19 remains grave. Traditional Chinese medicine plays a vital role in the precaution and therapy of sicknesses. At present, there is a lack of drugs for treating these diseases, so it is necessary to develop drugs for treating COVID-19 related ALI. Fagopyrum dibotrys (D. Don) Hara is an annual plant of the Polygonaceae family and one of the long-history used traditional medicine in China. In recent years, its rhizomes (medicinal parts) have attracted the attention of scholars at home and abroad due to their significant anti-inflammatory, antibacterial and anticancer activities. It can work on SARS-COV-2 with numerous components, targets, and pathways, and has a certain effect on coronavirus disease 2019 (COVID-19) related acute lung injury (ALI). However, there are few systematic studies on its aerial parts (including stems and leaves) and its potential therapeutic mechanism has not been studied. The phytochemical constituents of rhizome of F. dibotrys were collected using TCMSP database. And metabolites of F. dibotrys' s aerial parts were detected by metabonomics. The phytochemical targets of F. dibotrys were predicted by the PharmMapper website tool. COVID-19 and ALI-related genes were retrieved from GeneCards. Cross targets and active phytochemicals of COVID-19 and ALI related genes in F. dibotrys were enriched by gene ontology (GO) and KEGG by metscape bioinformatics tools. The interplay network entre active phytochemicals and anti COVID-19 and ALI targets was established and broke down using Cytoscape software. Discovery Studio (version 2019) was used to perform molecular docking of crux active plant chemicals with anti COVID-19 and ALI targets. We identified 1136 chemicals from the aerial parts of F. dibotrys, among which 47 were active flavonoids and phenolic chemicals. A total of 61 chemicals were searched from the rhizome of F. dibotrys, and 15 of them were active chemicals. So there are 6 commonly key active chemicals at the aerial parts and the rhizome of F. dibotrys, 89 these phytochemicals's potential targets, and 211 COVID-19 and ALI related genes. GO enrichment bespoken that F. dibotrys might be involved in influencing gene targets contained numerous biological processes, for instance, negative regulation of megakaryocyte differentiation, regulation of DNA metabolic process, which could be put down to its anti COVID-19 associated ALI effects. KEGG pathway indicated that viral carcinogenesis, spliceosome, salmonella infection, coronavirus disease - COVID-19, legionellosis and human immunodeficiency virus 1 infection pathway are the primary pathways obsessed in the anti COVID-19 associated ALI effects of F. dibotrys. Molecular docking confirmed that the 6 critical active phytochemicals of F. dibotrys, such as luteolin, (+) -epicatechin, quercetin, isorhamnetin, (+) -catechin, and (-) -catechin gallate, can combine with kernel therapeutic targets NEDD8, SRPK1, DCUN1D1, and PARP1. In vitro activity experiments showed that the total antioxidant capacity of the aerial parts and rhizomes of F. dibotrys increased with the increase of concentration in a certain range. In addition, as a whole, the antioxidant capacity of the aerial part of F. dibotrys was stronger than that of the rhizome. Our research afford cues for farther exploration of the anti COVID-19 associated ALI chemical compositions and mechanisms of F. dibotrys and afford scientific foundation for progressing modern anti COVID-19 associated ALI drugs based on phytochemicals in F. dibotrys. We also fully developed the medicinal value of F. dibotrys' s aerial parts, which can effectively avoid the waste of resources. Meanwhile, our work provides a new strategy for integrating metabonomics, network pharmacology, and molecular docking techniques which was an efficient way for recognizing effective constituents and mechanisms valid to the pharmacologic actions of traditional Chinese medicine.

Evidence for frequent concurrent DCUN1D1, FGFR1, BCL9 gene copy number amplification in squamous cell lung cancer

Non-small cell lung cancer (NSCLC) targeted therapies are mostly based on activating mutations and rearrangements which are rare events in Lung Squamous Cell Carcinomas (LUSC). Recently advances in immunotherapy have improved the therapeutic repository for LUSC, but there is still an urgent need for novel targets and biomarkers. We examined 73 cases of LUSC for relative copy number amplification of DCUN1D1, BCL9, FGFR1 and ERBB2 genes and searched for correlations with molecular alterations and clinicopathological characteristics. In our cohort BCL9 gene was amplified in 57.5 % of the cases, followed by DCUN1D1 in 37 %, FGFR1 in 19 % whereas none of the cases were amplified in ERBB2 gene. The majority of the samples exhibited amplification in at least one gene while half of them displayed concurrent amplification of two/three genes. Interestingly, 93 % of the FGFR1 amplified cases were also found co amplified with DCUN1D1 and/or BCL9 genes. Linear correlations were found between BCL9 and DCUN1D1 as well as BCL9 and FGFR1 gene amplification. BCL9 and DCUN1D1 genes' amplification was correlated with poorly differentiated tumors (p = 0.035 and p = 0.056 respectively), implying their possible role in tumor aggressiveness. This is the first study, to the best of our knowledge that examines the correlation of DCUN1D1 and BCL9 genes relative copy number amplification with molecular alterations and clinicopathologic characteristics of squamous cell lung cancer tissue samples. Our findings show concurrent amplification of genes in different chromosomes, with possible involvement in tumor aggressiveness. These results support the complexity of LUSC tumorigenesis and imply the necessity of multiple biomarkers / targets for a more effective therapeutic result in LUSC.

Development of phenyltriazole thiol-based derivatives as highly potent inhibitors of DCN1-UBC12 interaction

Defective in cullin neddylation 1(DCN1) is a co-E3 ligase that is important for cullin neddylation. Dysregulation of DCN1 highly correlates with the development of various cancers. Herein, from the initial high-throughput screening, a novel hit compound 5a containing a phenyltriazole thiol core (IC₅₀ value of 0.95 μM for DCN1-UBC12 interaction) was discovered. Further structure-based optimization leads to the development of SK-464 (IC₅₀ value of 26 nM). We found that SK-464 not only directly bound to DCN1 in vitro, but also engaged cellular DCN1, suppressed the neddylation of cullin3, and hindered the migration and invasion of two DCN1-overexpressed squamous carcinoma cell lines (KYSE70 and H2170). These findings indicate that SK-464 may be a novel lead compound targeting DCN1-UBC12 interaction.

DCUN1D1 facilitates tumor metastasis by activating FAK signaling and up-regulates PD-L1 in non-small-cell lung cancer

E3 ubiquitin ligases, which are key enzymes in the ubiquitin proteasome system, catalyze the ubiquitination of proteins to target them for proteasomal degradation. Emerging evidence suggests that E3 ubiquitin ligases play important roles in the development and progression of lung cancer. In our study, we characterized the gene expression landscape of lung cancer using data obtained from TCGA to explore the changes in E3 ubiquitin ligase containing the regulators of E3 ubiquitin ligase activity. Overall, most gene expression changes occurred in NSCLC tissues compared with adjacent normal ones. In total, 48 E3 ubiquitin ligases containing the regulators were up-regulated in NSCLC tissues compared with their levels in normal tissues. We analyzed the expression of up-regulated E3 ubiquitin ligases containing the regulators in two publicly available transcriptome data sets (GSE13213 and GSE30219). We found that four E3 ubiquitin ligases (UHRF1, BRCA1, TRAIP and HLTF) and one regulator of ubiquitin E3 activity DCUN1D1 that were dramatically up-regulated in cancer were significantly associated with tumor metastasis and patient's poor prognosis both in two transcriptome data sets. Next, clinical analysis indicated that the expression levels of DCUN1D1 correlated with clinical stage and lymph node metastasis in NSCLC patients as determined by quantitative reverse transcription-PCR. Furthermore, functional assays showed that DCUN1D1 promoted NSCLC cell invasion and migration as determined by transwell assay in vitro. Mechanistically, we found that the C-terminal Cullin binding domain leads to oncogenic activity and the UBA domain acts as a negative regulator of DCUN1D1 function in NSCLC. Moreover, DCUN1D1 activated the FAK oncogenic signaling pathway and up-regulated PD-L1. Taken together, our results demonstrate that DCUN1D1 is a metastasis regulator and suggest a new therapeutic option for NSCLC metastasis.

MicroRNA-302 inhibits cell migration and invasion in cervical cancer by targeting DCUN1D1

MicroRNA serve crucial roles in a variety of human cancer types. The miR-302-367 cluster has been reported to suppress the proliferation of cervical carcinoma cells through the novel target AKT1; however, the molecular mechanism of miR-302 in cervical cancer metastasis remains unclear. The present study aimed to investigate the clinical significance of miR-302-3p expression in cervical cancer, and to examine the regulatory mechanism of miR-302-3p in the malignant phenotypes of cervical cancer cells. The present data indicated that miR-302-3p was significantly downregulated in cervical cancer tissues compared with the level in adjacent non-tumor tissues, and low expression of miR-302-3p was significantly associated with node metastasis, advanced clinical stage, and poor prognosis in patients with cervical cancer. Restoration of miR-302-3p expression caused a significant reduction in cervical cancer cell migration and invasion. Defective in cullin neddylation 1 domain containing 1 (DCUN1D1) was identified as a novel target gene of miR-302-3p, and miR-302-3p negatively regulated the mRNA and protein expression of DCUN1D1 in cervical cancer HeLa cells. Additionally, overexpression of DCUN1D1 rescued the effects of miR-302-3p on the migration and invasion of cervical cancer cells. Furthermore, DCUN1D1 was upregulated in cervical cancer tissues compared with the levels in adjacent tissues, and its high expression was associated with node metastasis, advanced clinical stage, and shorter survival time in patients with cervical cancer. Notably, a negative correlation between miR-302-3p and DCUN1D1 expression in cervical cancer tissues was observed. Taken together, the present study suggests that miR-302-3p serves a suppressive role in cervical cancer metastasis, partly at least, via directly targeting DCUN1D1. Therefore, miR-302-3p/DCUN1D1 may be a potential therapeutic target for cervical cancer treatment.

MicroRNA‑195 inhibits cell proliferation, migration and invasion by targeting defective in cullin neddylation 1 domain containing 1 in cervical cancer

MicroRNAs (miRs), a class of small non-coding RNAs, have been demonstrated to perform promoting or suppressive roles in various types of human malignancy. Deregulation of miR-195 has been observed in numerous types of human cancer, including cervical cancer; however, the detailed molecular mechanism of miR-195 underlying the malignant progression of cervical cancer remains largely unclear. In the present study, miR-195 was significantly down-regulated in cervical cancer tissue samples compared with adjacent non-tumor tissue samples, and the reduced expression level of miR-195 was associated with node metastasis and an advanced clinical stage in cervical cancer. Furthermore, the patients with low miR-195 expression levels demonstrated shorter survival times when compared with those with high miR-195 expression levels. In vitro experiments indicated that miR-195 exerted suppressive effects on the proliferation, migration and invasion of cervical cancer cells. Luciferase reporter gene assay identified defective in cullin neddylation 1 domain containing 1 (DCUN1D1) as a novel target gene of miR-195 and the expression level of DCUN1D1 was identified to be negatively regulated by miR-195 in cervical cancer cells. DCUN1D1 was significantly upregulated in cervical cancer, with a negative correlation to miR-195 expression. Furthermore, upregulation of DCUN1D1 was associated with the malignant progression and poor prognosis of cervical cancer. DCUN1D1 overexpression attenuated the suppressive effects of miR-195 on the malignant phenotypes of cervical cancer cells. Notably, the expression levels of miR-195 were significantly lower in HeLa [human papilloma virus (HPV)18⁺] and SiHa (HPV16⁺) cells compared with those in C33A (HPV⁻) cells, and knockdown of E6 using small interfering RNA significantly increased the miR-195 expression while the DCUN1D1 expression level was reduced in HeLa and SiHa cells. Thus, these findings indicate that miR-195 exerts a suppressive role in cervical cancer by targeting DCUN1D1. Therefore, miR-195 may present as a potential therapeutic candidate for cervical cancer.

Discovery of an Orally Bioavailable Inhibitor of Defective in Cullin Neddylation 1 (DCN1)-Mediated Cullin Neddylation

We previously reported the discovery, validation, and structure-activity relationships of a series of piperidinyl ureas that potently inhibit the DCN1-UBE2M interaction. We demonstrated that compound 7 inhibits both the DCN1-UBE2M protein-protein interaction and DCN1-mediated cullin neddylation in biochemical assays and reduces levels of steady-state cullin neddylation in a squamous carcinoma cell line harboring DCN1 amplification. Although compound 7 exhibits good solubility and permeability, it is rapidly metabolized in microsomal models (CL_int = 170 mL/min/kg). This work lays out the discovery of an orally bioavailable analogue, NAcM-OPT (67). Compound 67 retains the favorable biochemical and cellular activity of compound 7 but is significantly more stable both in vitro and in vivo. Compound 67 is orally bioavailable, well tolerated in mice, and currently used to study the effects of acute pharmacologic inhibition of the DCN1-UBE2M interaction on the NEDD8/CUL pathway.

MicroRNA-218 inhibits EMT, migration and invasion by targeting SFMBT1 and DCUN1D1 in cervical cancer

Repeated infection with high-risk HPV is a major cause for the development and metastasis of human cervical cancer, even though the mechanism of the metastasis is still not completely understood. Here, we reported that miR-218 (microRNA-218) was downregulated in cervical cancer tissues, especially in metastatic cancer tissues. We found that miR-218 expression was associated with clinicopathological characteristics of patients with cervical cancer. MiR-218 overexpression inhibited Epithelial-Mesenchymal Transition (EMT), migration and invasiveness of cervical cancer cells in vitro. Moreover, miR-218 repressed the expression of SFMFBT1 (Scm-like with four MBT domains 1) and DCUN1D1 (defective in cullin neddylation 1, domain containing 1) by direct binding to the 3′UTRs of the mRNAs. The overexpression of SFMBT1 induced EMT and increased the migration and invasiveness of cervical cancer cells, while the overexpression of DCUN1D1 increased the migration and invasiveness of these cells, but did not induce EMT. An inverse correlation was observed between the expression of miR-218 and DCUN1D1 protein in cervical cancer tissues. Importantly, HPV16 E6 downregulated the expression of miR-218 in cervical cancer, while miR-218 rescued the promotion effect of HPV16 E6 on the expression of SFMBT1 and DCUN1D1. Taken together, our results revealed that HPV16 E6 promoted EMT and invasion in cervical cancer via the repression of miR-218, while miR-218 inhibited EMT and invasion in cervical cancer by targeting SFMBT1 and DCUN1D1.

Expression of DCUN1D1 in laryngeal squamous cell carcinoma and its inhibiting effect on TU-177 cells after interfered by RNA

Expression of DCUN1D1 in laryngeal squamous cell carcinoma (LSCC) and its inhibition by small interfering RNA (siRNA) target in the TU-177 cells was investigated. Immunohistochemistry was used to detect the expression level of DCUN1D1 in LSCC tissue in 140 cases and to analyze its relationship with clinical pathological characteristics. siRNA expression plasmid targeting DCUN1D1 was constructed and transferred into TU-177 cells. The effect of siRNA target DCUN1D1 gene silencing on proliferation, invasion and migration of TU-177 cells were observed by MTS assay and Transwell experiment. The expression levels of focal adhesion kinase (FAK) and matrix metalloproteinase-2(MMP-2) were detected by western blot. Expression level of DCUN1D1 protein increased significantly in T3 + T4, N+, and III + IV stages of LSCC patients (P < .05). After DCUN1D1 was targeted by siRNA, the DCUN1D1 protein level decreased 67% in siRNA-3 group, where average absorbance value was lower than the control and blank group with significant difference(F = 6.076, P < .05) in MTS assay, meantime migration, and invasion cells in each vision were the same (F = 19.851, F = 25.454, P < .01) in the Transwell experiment. The expression level of FAK and MMP-2 was significantly down-regulated in siRNA-3 group (F = 28.896, F = 40.240, P < .01). DCUN1D1 is associated with progression and prognosis of LSCC. After siRNA based target on DCUN1D1, TU-177 cells growth was inhibited and invasion of malignant tumour was diminished by reducing the expression of FAK and MMP-2. DCUN1D1 is could become a potential new target for the treatment of LSCC.

MicroRNA-195 inhibits growth and invasion of laryngeal carcinoma cells by directly targeting DCUN1D1

MicroRNAs (miRNAs) are a class of small, non-coding RNAs that regulate gene expression and are involved in cell biological processes. The aberrant expression of miR-195 has been found in various types of human cancer. However, the effect of miR-195 on the initiation and development of laryngeal squamous cell carcinoma (LSCC) remains to be elucidated. Accordingly, in the present study, we detected the expression level of miR-195 in the LSCC and the normal tissues and found that miR-195 were significantly downregulated in the LSCC tissues. Gain-of-function or loss-of-function studies including cell proliferation, wound healing assay, Transwell assay, cell cycle and apoptosis assays were performed to investigate the biological function of miR-195. Luciferase reporter assay and the rescue study confirmed that DCUN1D1 was a target of miR-195. Furthermore, DCUN1D1 expression levels were found to be upregulated in laryngeal tissues and to have a negative correlation with miR-195. We also found that both miR-195 and DCUN1D1 siRNAs can inhibit cell invasion possibly through downregulating Matrix metalloproteinase-2 (MMP-2) and Matrix metalloproteinase-9 (MMP-9) at the post-transcriptional level, which can be attenuated by restoring the expression of DCUN1D1. In summary, these data suggest that low expression of miR-195 contributes to the poor prognosis of LSCC and miR-195 regulates the proliferation and invasion ability of LSCC cells in vitro. miR-195 may suppress growth and invasion of LSCC cells possibly through targeting DCUN1D1, which would provide a candidate target for cancer therapy.

MicroRNA-520b Functions as a Tumor Suppressor in Colorectal Cancer by Inhibiting Defective in Cullin Neddylation 1 Domain Containing 1 (DCUN1D1)

MicroRNAs (miRs), a class of small noncoding RNAs, are important regulators for gene expression through directly binding to the 3′-untranslated region (3′-UTR) of their target mRNA. Recently, downregulation of miR-520b has been observed in several common human cancers. However, the exact role of miR-520b in colorectal cancer (CRC) has not previously been studied. In this study, our data showed that miR-520b was significantly downregulated in CRC and cell lines when compared with adjacent normal tissues and a normal intestinal epithelial cell line. Low expression of miR-520b was notably associated with the malignant progress and a shorter survival time for CRC patients. Restoration of miR-520b inhibited cell proliferation, migration, invasion, and epithelial–mesenchymal transition (EMT) in CRC cells. Defective in cullin neddylation 1 domain containing 1 (DCUN1D1) was then identified as a novel target gene of miR-520b in CRC cells. The expression of DCUN1D1 was significantly increased in CRC, with a negative correlation to miR-520b expression in CRC tissues. Moreover, a high expression of DCUN1D1 was significantly associated with the malignant progress and a poor prognosis for CRC patients. Furthermore, overexpression of DCUN1D1 rescued the miR-520b-mediated malignant phenotypes and EMT in CRC cells. The data demonstrate that miR-520b functions as a tumor suppressor in CRC through targeting DCUN1D1, suggesting that miR-520b may become a potential therapeutic target for the treatment of CRC.

The molecular biology of lung cancer brain metastasis: an overview of current comprehensions and future perspectives

Brain metastases occur in 20-40% of patients with advanced malignancies and lung cancer is one of the most common causes of brain metastases. The occurrence of brain metastases is associated with poor prognosis and high morbidity in patients with advanced lung cancer, even after intensive multimodal therapy. Progress in treating brain metastases has been hampered by a lack of model systems, a lack of human tissue samples, and the exclusion of brain metastatic patients from many clinical trials. While the biology of brain metastasis is still poorly understood, it is encouraging to see more efforts are beginning to be directed toward the study of brain metastasis. During the multi-step process of metastasis, functional significance of gene expressions, changes in brain vasculature, abnormal secretion of soluble factors and activation of autocrine/paracrine signaling are considered to contribute to the brain metastasis development. A better understanding of the mechanism of this disease will help us to identify the appropriate therapeutic strategies, which leads to circumvent brain metastases. Recent findings on the biology of lung cancer brain metastases and translational leads identified by molecular studies are discussed in this review.

Ubiquitin-specific protease 4 controls metastatic potential through β-catenin stabilization in brain metastatic lung adenocarcinoma

Brain metastasis is the most common type of intracranial cancer and is the main cause of cancer-associated mortality. Brain metastasis mainly originates from lung cancer. Using a previously established in vitro brain metastatic model, we found that brain metastatic PC14PE6/LvBr4 cells exhibited higher expression of β-catenin and increased migratory activity than parental PC14PE6 cells. Knockdown of β-catenin dramatically suppressed the motility and invasiveness of PC14PE6/LvBr4 cells, indicating β-catenin is involved in controlling metastatic potential. Since β-catenin protein was increased without a significant change in its mRNA levels, the mechanism underlying increased β-catenin stability was investigated. We found that ubiquitin-specific protease 4 (USP4), recently identified as a β-catenin-specific deubiquitinylating enzyme, was highly expressed in PC14PE6/LvBr4 cells and involved in the increased stability of β-catenin protein. Similar to β-catenin knockdown, USP4-silenced PC14PE6/LvBr4 cells showed decreased migratory and invasive abilities. Moreover, knockdown of both USP4 and β-catenin inhibited clonogenicity and induced mesenchymal-epithelial transition by downregulating ZEB1 in PC14PE6/LvBr4 cells. Using bioluminescence imaging, we found that knockdown of USP4 suppressed brain metastasis in vivo and significantly increased overall survival and brain metastasis-free survival. Taken together, our results indicate that USP4 is a promising therapeutic target for brain metastasis in patients with lung adenocarcinoma.

Blood-brain Barrier Remodeling during Brain Metastasis Formation

Our understanding of the process of metastatic progression has improved markedly over the past decades, yet metastasis remains the most enigmatic component of cancer pathogenesis. This lack of knowledge has serious health-related implications, since metastasis is responsible for 90% of all cancer-related mortalities. The brain is considered a sanctuary site for metastatic tumor growth, where the blood-brain barrier (BBB) and other components of the brain microenvironment, provide protection to the tumor cells from immune surveillance, chemotherapeutics and other potentially harmful substances. The interactions between tumor cells and the brain microenvironment, principally brain vascular endothelium, are the critical determinants in their progression toward metastasis, dormancy, or clearance. This review discusses current knowledge of the biology of metastatic progression, with a particular focus on the tumor cell migration and colonization in the brain.

Osteosarcoma tissues and cell lines from patients with differing serum alkaline phosphatase concentrations display minimal differences in gene expression patterns

Serum alkaline phosphatase (ALP) concentration is a prognostic factor for osteosarcoma in multiple studies, although its biological significance remains incompletely understood. To determine whether gene expression patterns differed in osteosarcoma from patients with differing serum ALP concentrations, microarray analysis was performed on 18 primary osteosarcoma samples and six osteosarcoma cell lines from dogs with normal and increased serum ALP concentration. No differences in gene expression patterns were noted between tumours or cell lines with differing serum ALP concentration using a gene-specific two-sample t-test. Using a more sensitive empirical Bayes procedure, defective in cullin neddylation 1 domain containing 1 (DCUN1D1) was increased in both the tissue and cell lines of the normal ALP group. Using quantitative PCR (qPCR), differences in DCUN1D1 expression between the two groups failed to reach significance. The homogeneity of gene expression patterns of osteosarcoma associated differing serum ALP concentrations are consistent with previous studies suggesting serum ALP concentration is not associated with intrinsic differences of osteosarcoma cells.

Value of oncogenes for the prediction of brain metastases at initial diagnosis: a review of published data

Identifying cancer patients who are at high risk of developing brain metastases at initial diagnosis and applying effective intervention or monitoring strategies is of vital importance. Recent advances in the biology of brain metastases revealed that some oncogenes from primary tumors may be potential markers for identifying cancer patients likely to metastasize to the brain. We here summarize data on the mechanisms of brain metastases supporting the involvement of oncogene changes in the brain metastatic evolution. We also review the available evidence on clinical studies of oncogenes in the prediction of cancer patients with high incidence of brain metastases.

Coamplification and cooperation: toward identifying biologically relevant oncogenes

Identification of biologically relevant genes from genomic assays is limited by the complexity of changes present in most solid tumors. Assessing for coactivation of functionally related genes resulted in the identification of SENP2, DCUN1D1, and DVL3--consensus candidates that drive selection for 3q amplification in lung squamous cell carcinomas.

Predictive biochemical-markers for the development of brain metastases from lung cancer: clinical evidence and future directions

BACKGROUND

Brain metastases are a common complication of patients with lung cancer and lung cancer is one of the most common causes of brain metastases. The occurrence of brain metastases is associated with poor prognosis and high morbidity, even after intensive multimodal therapy. Therefore, identifying lung cancer patients with who are at high risk of developing brain metastases and applying effect intervention is important to reduce or delay the incidence of brain metastases. Biochemical-markers may meet an unmet need for following patients' mechanisms of brain metastases.

METHODS

Data for this review were identified by searches of Pubmed and Cochrane databases, and references from relevant articles using the search terms "lung cancer" and "brain metastasis". Meeting abstracts, unpublished reports and review articles were not considered.

RESULTS

Clinical results for pathological and circulating markers including cancer molecular subtypes, miRNA, single nucleotide polymorphisms, and other markers are presented. However, these biochemical-markers are not yet established surrogate assessments for prediction of brain metastases.

CONCLUSIONS

Biochemical-markers reported allowed physicians to identify which patients with lung cancer are at high risk for brain metastases. Prospective randomized clinical studies are needed to further assess the utility of these biochemical-markers.