NUCKS overexpression in breast cancer

Exploring Intrinsic Disorder in Human Synucleins and Associated Proteins

In this work, we explored the intrinsic disorder status of the three members of the synuclein family of proteins-α-, β-, and γ-synucleins-and showed that although all three human synucleins are highly disordered, the highest levels of disorder are observed in γ-synuclein. Our analysis of the peculiarities of the amino acid sequences and modeled 3D structures of the human synuclein family members revealed that the pathological mutations A30P, E46K, H50Q, A53T, and A53E associated with the early onset of Parkinson's disease caused some increase in the local disorder propensity of human α-synuclein. A comparative sequence-based analysis of the synuclein proteins from various evolutionary distant species and evaluation of their levels of intrinsic disorder using a set of commonly used bioinformatics tools revealed that, irrespective of their origin, all members of the synuclein family analyzed in this study were predicted to be highly disordered proteins, indicating that their intrinsically disordered nature represents an evolutionary conserved and therefore functionally important feature. A detailed functional disorder analysis of the proteins in the interactomes of the human synuclein family members utilizing a set of commonly used disorder analysis tools showed that the human α-synuclein interactome has relatively higher levels of intrinsic disorder as compared with the interactomes of human β- and γ- synucleins and revealed that, relative to the β- and γ-synuclein interactomes, α-synuclein interactors are involved in a much broader spectrum of highly diversified functional pathways. Although proteins interacting with three human synucleins were characterized by highly diversified functionalities, this analysis also revealed that the interactors of three human synucleins were involved in three common functional pathways, such as the synaptic vesicle cycle, serotonergic synapse, and retrograde endocannabinoid signaling. Taken together, these observations highlight the critical importance of the intrinsic disorder of human synucleins and their interactors in various neuronal processes.

Acts as a Promising Novel Biomarker for the Prognosis of Patients with Hepatocellular Carcinoma

Objective: Nuclear casein kinase and cyclin-dependent kinase substrate 1 (NUCKS1) is highly expressed in some tumors, including hepatocellular carcinoma (HCC). However, its clinical significance in HCC prognosis is still unclear. The aim of this study was to explore the expression and prognostic value of NUCKS1 in HCC. Materials and Methods: Quantitative real-time polymerase chain reaction was used to detect relative expression of NUCKS1 mRNA in HCC tissues and corresponding adjacent normal tissues. The relationship between NUCKS1 expression and clinical characteristics of patients was analyzed by χ2 test. Kaplan-Meier method and Cox regression analysis were applied to estimate prognostic value of NUCKS1 in HCC. Results: Compared with normal ones, the expression of NUCKS1 mRNA was significantly upregulated in HCC tissues (p < 0.001). Besides, NUCKS1 expression was closely associated with tumor differentiation, tumor node metastasis stage, vascular invasion, and metastasis (p < 0.05). Kaplan-Meier analysis revealed that overall survival was obviously longer in HCC patients with low expression of NUCKS1 than those with high NUCKS1 expression (log rank test, p = 0.001). NUCKS1 might be an independent prognostic factor for HCC patients (HR = 1.905, 95% CI = 1.106-3.283, p = 0.020). Conclusions: NUCKS1 may be correlated with the progression of HCC and serve as a potential predictive factor for the prognosis of this disease.

NUCKS1 is a highly modified, chromatin-associated protein involved in a diverse set of biological and pathophysiological processes

The Nuclear Casein and Cyclin-dependent Kinase Substrate 1 (NUCKS1) protein is highly conserved in vertebrates, predominantly localized to the nucleus and one of the most heavily modified proteins in the human proteome. NUCKS1 expression is high in stem cells and the brain, developmentally regulated in mice and associated with several diverse malignancies in humans, including cancer, metabolic syndrome and Parkinson's disease. NUCKS1 function has been linked to modulating chromatin architecture and transcription, DNA repair and cell cycle regulation. In this review, we summarize and discuss the published information on NUCKS1 and highlight the questions that remain to be addressed to better understand the complex biology of this multifaceted protein.

Hsa_circ_0001550 facilitates colorectal cancer progression through mediating microRNA-4262/nuclear casein kinase and cyclin-dependent kinase substrate 1 cascade

Background

Circular RNAs (circRNAs) play important roles in various malignancies, such as colorectal cancer (CRC). However, the function of hsa_circ_0001550 in CRC remains to be elucidated.

Methods

The expression levels of hsa_circ_0001550, microRNA (miR)‐4262, and nuclear casein kinase and cyclin‐dependent kinase substrate 1 (NUCKS1) were determined by real‐time qPCR. Cell biological behaviors were evaluated via colony formation assay, transwell assay, flow cytometry, and sphere formation assays. The target relationship was validated via dual‐luciferase reporter and RNA pull‐down assays. Protein expression was analyzed by western blot. Xenograft tumor model was adopted to evaluate hsa_circ_0001550 function in vivo.

Results

Hsa_circ_0001550 enrichment was enhanced in CRC tissue specimens and cell lines. Hsa_circ_0001550 absence hindered CRC cell proliferation, metastasis, stemness, and caused apoptosis. Hsa_circ_0001550 targeted miR‐4262, and hsa_circ_0001550 absence‐caused impacts were diminished by anti‐miR‐4262. MiR‐4262 targeted NUCKS1. Hsa_circ_0001550 had positive regulation on NUCKS1 expression. NUCKS1 overexpression overturned the influences of hsa_circ_0001550 silencingon CRC cell progression. Hsa_circ_0001550 interference notably blocked in vivo xenograft tumor growth.

Conclusion

Hsa_circ_0001550 facilitated CRC progression by binding to miR‐4262 to positively regulate NUCKS1 abundance.

Integrated In Silico Analyses Identify PUF60 and SF3A3 as New Spliceosome-Related Breast Cancer RNA-Binding Proteins

More women are diagnosed with breast cancer (BC) than any other type of cancer. Although large-scale efforts have completely redefined cancer, a cure remains unattainable. In that respect, new molecular functions of the cell should be investigated, such as post-transcriptional regulation. RNA-binding proteins (RBPs) are emerging as critical post-transcriptional modulators of tumorigenesis, but only a few have clear roles in BC. To recognize new putative breast cancer RNA-binding proteins, we performed integrated in silico analyses of all human RBPs (n = 1392) in three major cancer databases and identified five putative BC RBPs (PUF60, TFRC, KPNB1, NSF, and SF3A3), which showed robust oncogenic features related to their genomic alterations, immunohistochemical changes, high interconnectivity with cancer driver genes (CDGs), and tumor vulnerabilities. Interestingly, some of these RBPs have never been studied in BC, but their oncogenic functions have been described in other cancer types. Subsequent analyses revealed PUF60 and SF3A3 as central elements of a spliceosome-related cluster involving RBPs and CDGs. Further research should focus on the mechanisms by which these proteins could promote breast tumorigenesis, with the potential to reveal new therapeutic pathways along with novel drug-development strategies.

The NUCKS1-SKP2-p21/p27 axis controls S phase entry

Efficient entry into S phase of the cell cycle is necessary for embryonic development and tissue homoeostasis. However, unscheduled S phase entry triggers DNA damage and promotes oncogenesis, underlining the requirement for strict control. Here, we identify the NUCKS1-SKP2-p21/p27 axis as a checkpoint pathway for the G1/S transition. In response to mitogenic stimulation, NUCKS1, a transcription factor, is recruited to chromatin to activate expression of SKP2, the F-box component of the SCFSKP2 ubiquitin ligase, leading to degradation of p21 and p27 and promoting progression into S phase. In contrast, DNA damage induces p53-dependent transcriptional repression of NUCKS1, leading to SKP2 downregulation, p21/p27 upregulation, and cell cycle arrest. We propose that the NUCKS1-SKP2-p21/p27 axis integrates mitogenic and DNA damage signalling to control S phase entry. The Cancer Genome Atlas (TCGA) data reveal that this mechanism is hijacked in many cancers, potentially allowing cancer cells to sustain uncontrolled proliferation.

NUCKS1 Promotes Proliferation, Invasion and Migration of Non-Small Cell Lung Cancer by Upregulating CDK1 Expression

Background

Non-small cell lung cancer (NSCLC) is a predominant type of lung cancer with a high mortality rate.

Objective

The aim of this study is to investigate the roles of nuclear casein kinase and cyclin-dependent kinase substrate 1 (NUCKS1) in NSCLC and to identify the potential mechanisms.

Materials and Methods

The expression of NUCKS1 in several NSCLC cells was detected firstly. Then, NUCKS1 was overexpressed or silenced in both A549 and NCI-H460 cells, where cell proliferation, invasion and migration were, respectively, determined, using CCK-8, colony formation assay, transwell and wound healing assays. Cell cycle analysis was performed, and the expression-associated proteins were detected by Western blotting. Subsequently, NCI-H460 cells with NUCKS1 overexpression for the subsequent tumor-bearing experiment. And the NUCKS1 expression in tumor tissues was measured by means of immunohistochemistry and Western blotting. Additionally, the STRING database predicted that Cyclin-Dependent Kinase 1 (CDK1) would bind to NUSK1, which was verified by the co-immunoprecipitation assay. Then, CDK1 was silenced by transfection with short hairpin RNA (shRNA)-CDK-1 or by exposure to CDK1 inhibitor p2767-00. And the biological characteristics of proliferation, invasion and migration were examined.

Results

Results indicated that NUCKS1 was overly expressed in NSCLC cells, and its overexpression promoted proliferation, invasion and migration of both A549 and NCI-H460 cells while NUCKS1 knockdown displayed the opposite effects. Moreover, the results of the xenograft experiments revealed that NUCKS1-upregulation promoted the tumor growth. Furthermore, the immunoprecipitation assay verified CDK1’s interaction with NUCKS1, and CDK1 knockdown alleviates the impact of NUCKS1 overexpression on NSCLC cell proliferation, invasion and migration.

Conclusion

Taken together, these findings demonstrated that NUCKS1 promotes proliferation, invasion and migration of NSCLC by upregulating CDK1, providing a novel putative target for the clinical treatment of NSCLC.

NUCKS promotes cell proliferation and suppresses autophagy through the mTOR-Beclin1 pathway in gastric cancer

Background

Nuclear casein kinase and cyclin-dependent kinase substrate (NUCKS), a novel gene first reported in 2001, is a member of the high mobility group (HMG) family. Although very little is known regarding the biological roles of NUCKS, emerging clinical evidence suggests that the NUCKS protein can be used as a biomarker and therapeutic target in various human ailments, including several types of cancer.

Methods

We first assessed the potential correlation between NUCKS expression and gastric cancer prognosis. Then functional experiments were conducted to evaluate the effects of NUCKS in cell proliferation, cell cycle, apoptosis and autophagy. Finally, the roles of NUCKS on gastric cancer were examined in vivo.

Results

We found that NUCKS was overexpressed in gastric cancer patients with poor prognosis. Through manipulating NUCKS expression, it was observed to be positively associated with cell proliferation in vitro and in vivo. NUCKS knockdown could induce cell cycle arrest and apoptosis. Then further investigation indicated that NUCKS knockdown could also significantly induce a marked increase in autophagy though the mTOR-Beclin1 pathway, which could be was rescued by NUCKS restoration. Moreover, silencing Beclin1 in NUCKS knockdown cells or adding rapamycin in NUCKS-overexpressed cells also confirmed these results.

Conclusions

Our findings revealed that NUCKS functions as an oncogene and an inhibitor of autophagy in gastric cancer. Thus, the downregulation or inhibition of NUCKS may be a potential therapeutic strategy for gastric cancer.

Recent Trends of microRNA Significance in Pediatric Population Glioblastoma and Current Knowledge of Micro RNA Function in Glioblastoma Multiforme

Central nervous system tumors are a significant problem for modern medicine because of their location. The explanation of the importance of microRNA (miRNA) in the development of cancerous changes plays an important role in this respect. The first papers describing the presence of miRNA were published in the 1990s. The role of miRNA has been pointed out in many medical conditions such as kidney disease, diabetes, neurodegenerative disorder, arthritis and cancer. There are several miRNAs responsible for invasiveness, apoptosis, resistance to treatment, angiogenesis, proliferation and immunology, and many others. The research conducted in recent years analyzing this group of tumors has shown the important role of miRNA in the course of gliomagenesis. These particles seem to participate in many stages of the development of cancer processes, such as proliferation, angiogenesis, regulation of apoptosis or cell resistance to cytostatics.

A microRNA profile of pediatric glioblastoma: The role of NUCKS1 upregulation

MicroRNAs (miRNAs/miRs) are a novel class of gene regulators that may be involved in tumor chemoresistance. Recently, specific miRNA expression profiles have been identified in adult glioblastoma (aGBM), but there are only limited data available on the role of miRNAs in pediatric GBM (pGBM). In the present study, the expression profile of miRNAs was examined in seven pGBMs and three human GBM cell lines (U87MG, A172 and T98G), compared with a non-tumoral pool of pediatric cerebral cortex samples by microarray analysis. A set of differentially expressed miRNAs was identified, including miR-490, miR-876-3p, miR-876-5p, miR-448 and miR-137 (downregulated), as well as miR-501-3p (upregulated). Through bioinformatics analysis, a series of target genes was predicted. In addition, similar gene expression patterns in pGBMs and cell lines was confirmed. Of note, drug resistant T98G cells had upregulated nuclear casein kinase and cyclin-dependent kinase substrate 1 (NUCKS1) expression, a protein overexpressed in many tumors that serves an important role in cell proliferation and progression. On the basis of the present preliminary report, it could be intriguing to further investigate the relationship between each of the identified differentially expressed miRNAs and NUCKS1, in order to clarify their involvement in the multi-drug resistance mechanism of pGBMs.

Nucks1 synergizes with Trp53 to promote radiation lymphomagenesis in mice

NUCKS1 is a 27 kD vertebrate-specific protein, with a role in the DNA damage response. Here, we show that after 4 Gy total-body X-irradiation, Trp53+/− Nucks1+/− mice more rapidly developed tumors, particularly thymic lymphoma (TL), than Trp53+/− mice. TLs in both cohorts showed loss of heterozygosity (LOH) of the Trp53+ allele in essentially all cases. In contrast, LOH of the Nucks1+ allele was rare. Nucks1 expression correlated well with Nucks1 gene dosage in normal thymi, but was increased in the majority of TLs from Trp53+/− Nucks1+/− mice, suggesting that elevated Nucks1 message may be associated with progression towards malignancy in vivo. Trp53+/− Nucks1+/− mice frequently succumbed to CD4- CD8- TLs harboring translocations involving Igh but not Tcra/d, indicating TLs in Trp53+/− Nucks1+/− mice mostly originated prior to the double positive stage and at earlier lineage than TLs in Trp53+/- mice. Monoclonal rearrangements at Tcrb were more prevalent in TLs from Trp53+/− Nucks1+/− mice, as was infiltration of primary TL cells to distant organs (liver, kidney and spleen). We propose that, in the context of Trp53 deficiency, wild type levels of Nucks1 are required to suppress radiation-induced TL, likely through the role of the NUCKS1 protein in the DNA damage response.

Nondysplastic Ulcerative Colitis Has High Levels of the Homologous Recombination Repair Protein NUCKS1 and Low Levels of the DNA Damage Marker Gamma-H2AX

BACKGROUND

The colon and rectum are continuously exposed to oxidative stress that generates reactive oxygen species, which are a major cause of DNA double-strand breaks (DSB). Furthermore, chronic inflammatory diseases such as ulcerative colitis (UC) are characterized by an excess of reactive nitrogen species that can also lead to DNA double-strand breakage and genomic instability. We investigated the expression of the nuclear casein kinase and cyclin-dependent kinase substrate 1 (NUCKS1) protein in UC and sporadic colorectal cancer (CRC) due to its involvement in both DNA double-strand break repair and inflammatory signaling.

METHODS

NUCKS1 expression and expression of the DNA double-strand break marker gamma-H2AX (γH2AX) were assessed in formalin-fixed, paraffin-embedded UC and CRC patient biopsies using peroxidase immunohistochemistry. Expression levels for both proteins were evaluated together with previously published expression-level data for hTERT and TP53 proteins in the same material.

RESULTS

Nondysplastic UC lesions had 10-fold lower γH2AX expression and approximately 4-fold higher NUCKS1 expression compared with sporadic CRC, indicating minimal DNA DSB damage and heightened DNA DSB repair in these lesions, respectively. NUCKS1 expression in UC tended to decrease with increasing grades of dysplasia, whereas γH2AX, hTERT, and TP53 expression tended to increase with increasing grades of dysplasia. The highest γH2AX expression was seen in sporadic CRC, indicating considerable DNA DSB damage, whereas the highest NUCKS1 expression and hTERT expression were seen in nondysplastic UC.

CONCLUSIONS

Overall, our data suggest that NUCKS1 may be involved in DNA DSB repair and/or inflammatory signaling in UC, but a more thorough investigation of both pathways in UC is warranted.

MicroRNA-137 inhibits tumor growth and sensitizes chemosensitivity to paclitaxel and cisplatin in lung cancer

Chemotherapy resistance frequently drives tumour progression. However, the underlying molecular mechanisms are poorly characterized. In this study, we explored miR-137's role in the chemosensitivity of lung cancer. We found that the expression level of miR-137 is down-regulated in the human lung cancer tissues and the resistant cells strains: A549/paclitaxel(A549/PTX) and A549/cisplatin (A549/CDDP) when compared with lung cancer A549 cells. Moreover, we found that overe-expression of miR-137 inhibited cell proliferation, migration, cell survival and arrest the cell cycle in G1 phase in A549/PTX and A549/CDDP. Furthermore, Repression of miR-137 significantly promoted cell growth, migration, cell survival and cell cycle G1/S transition in A549 cells. We further demonstrated that the tumor suppressive role of miR-137 was mediated by negatively regulating Nuclear casein kinase and cyclin-dependent kinase substrate1(NUCKS1) protein expression. Importantly, miR-137 inhibits A549/PTX, A549/CDDP growth and angiogenesis in vivo. Our study is the first to identify the tumor suppressive role of over-expressed miR-137 in chemosensitivity. Identification of a novel miRNA-mediated pathway that regulates chemosensitivity in lung cancer will facilitate the development of novel therapeutic strategies in the future.

NUCKS nuclear elevated expression indicates progression and prognosis of ovarian cancer

NUCKS (nuclear, casein kinase, and cyclin-dependent kinase substrate) is implicated in the tumorigenesis of several human malignancies, but its role in ovarian cancer remains unknown. We aim to investigate NUCKS expression and its clinical significance in ovarian cancer. The messenger RNA expression of NUCKS was determined in normal and malignant ovarian tissues using quantitative polymerase chain reaction assay. Immunohistochemistry was applied to detect the status of NUCKS protein expression in 121 ovarian cancer tissues. NUCKS protein high expression was detected in 52 (43.0%) of 121 patients. NUCKS messenger RNA expression was gradually upregulated in non-metastatic ovarian cancers ( n = 20), metastatic ovarian cancers ( n = 20), and its matched metastatic lesions ( n = 20) in comparison with that in normal ovarian tissues ( n = 10; p < 0.05). Elevated expression of NUCKS in ovarian cancer was associated significantly with the Federation of Gynecology and Obstetrics stage ( p = 0.037), histological grade ( p = 0.003), residual disease ( p = 0.013), lymph node metastasis ( p = 0.002), response to chemotherapy ( p < 0.001), and recurrence ( p = 0.013). In the multivariate Cox analysis, NUCKS expression was an independent prognostic marker for overall survival and disease-free survival in ovarian cancer with p values of <0.001 for both. Especially, NUCKS overexpression had prognostic potential for overall survival and disease-free survival ( p < 0.001 for both) in advanced ovarian cancers and only for disease-free survival in early ovarian cancers ( p = 0.017). Our data suggest that NUCKS overexpression may contribute to progression and poor prognosis in ovarian cancer especially in advanced ovarian cancer.

Absence of NUCKS augments paracrine effects of mesenchymal stem cells-mediated cardiac protection

Bone marrow-derived mesenchymal stem cells (BM-MSCs) contribute to myocardial repair after myocardial infarction (MI) by secreting a panel of growth factors and cytokines. This study was to investigate the potential mechanisms of the nuclear casein kinase and cyclin-dependent kinase substrate 1 (NUCKS) in regulation of the profiles of BM-MSCs secretion and compare the therapeutic efficacy of NUCKS^-/-- and wide type-BM-MSCs (WT-BM-MSCs) on MI. The secretion profiles between NUCKS^-/-- and WT-BM-MSCs under hypoxia (1%O₂) were analyzed. Gene function analysis showed that compared with WT-BM-MSCs-conditioned medium (CdM), some genes over-presented in NUCKS^-/--BM-MSCs-CdM were closely associated with inflammatory response, regulation of cell proliferation, death, migration and secretion. Notably, VEGFa in NUCKS^-/--BM-MSCs-CdM was higher than that of WT-BM-MSCs-CdM. WT-BM-MSCs and NUCKS^-/--BM-MSCs were transplanted into the peri-infarct region in mice of MI. At 4 weeks after cell transplantation, NUCKS^-/-- or WT-BM-MSCs group significantly improved heart function and vessels density and reduced infarction size and apoptosis of cardiomyocytes. Furthermore, NUCKS^-/--BM-MSCs provided better cardioprotective effects than WT-BM-MSCs against MI. Our study demonstrates that depletion of NUCKS enhances the therapeutic efficacy of BM-MSCs for MI via regulating the secretion.

Identification of kinases phosphorylating 13 sites in the nuclear, DNA-binding protein NUCKS

NUCKS is a vertebrate specific, nuclear and DNA-binding phospho protein. The protein is highly expressed in rapidly dividing cells, and is overexpressed in a number of cancer tissues. The phosphorylation of NUCKS is cell cycle and DNA-damage regulated, but little is known about the responsible kinases. By utilizing in vitro and in vivo phosphorylation assays using isolated NUCKS as well as synthetic NUCKS-derived peptides in combination with mass spectrometry, phosphopeptide mapping, phosphphoamino acid analyses, phosphospecific antibodies and the use of specific kinase inhibitors, we found that NUCKS is phosphorylated on 11 sites by CK2. At least 7 of the CK2 sites are phosphorylated in vivo. We also found that NUCKS is phosphorylated on two sites by ATM kinase and DNA-PK in vitro, and is phosphorylated in vivo by ATM kinase in γ-irradiated cells. All together, we identified three kinases phosphorylating 13 out of 39 in vivo phosphorylated sites in mammalian NUCKS. The identification of CK2 and PIKK kinases as kinases phosphorylating NUCKS in vivo provide further evidence for the involvement of NUCKS in cell cycle control and DNA repair.

Identification of NUCKS1 as a putative oncogene and immunodiagnostic marker of hepatocellular carcinoma

Although the molecular mechanisms underpinning hepatocellular carcinoma (HCC) are unknown, gene copy number and associated mRNA expression changes are frequently reported. Comparative genomic hybridization arrays spotted with 4041 bacterial artificial chromosome clones were used to assess copy number changes in 45 HCC tissues. Seventy more HCC tissues were used to validate candidate genes by using western blots and immunohistochemistry. A total of 259 clones were associated with copy number changes that significantly differed between normal liver and HCC samples. The chromosomal region 1q32.1 containing the nuclear casein kinase and cyclin-dependent kinase substrate 1 (NUCKS1) gene was associated with tumor vascular invasion. Western blot analysis demonstrated that NUCKS1 was up-regulated in 37 of 70 (52.8%) HCC tissues compared with adjacent non-tumor tissues, and over-expressed in a vast majority of HCCs (44/52, 84.6%) as determined by immunohistochemical staining. Furthermore, immunostaining of both NUCKS1 and glypican-3 improved the diagnostic prediction of HCC. Knock-down of NUCKS1 by siRNA implied the decrease in cell viability of the Hep3B cell line and reduced tumor formation in a xenograft mouse model. NUCKS1 was identified as a potential oncogene at chromosomal 1q32.1 in patients with HCC, and it might be a valuable immunodiagnostic marker for HCC.

NUCKS1 is a novel RAD51AP1 paralog important for homologous recombination and genome stability

NUCKS1 (nuclear casein kinase and cyclin-dependent kinase substrate 1) is a 27 kD chromosomal, vertebrate-specific protein, for which limited functional data exist. Here, we demonstrate that NUCKS1 shares extensive sequence homology with RAD51AP1 (RAD51 associated protein 1), suggesting that these two proteins are paralogs. Similar to the phenotypic effects of RAD51AP1 knockdown, we find that depletion of NUCKS1 in human cells impairs DNA repair by homologous recombination (HR) and chromosome stability. Depletion of NUCKS1 also results in greatly increased cellular sensitivity to mitomycin C (MMC), and in increased levels of spontaneous and MMC-induced chromatid breaks. NUCKS1 is critical to maintaining wild type HR capacity, and, as observed for a number of proteins involved in the HR pathway, functional loss of NUCKS1 leads to a slow down in DNA replication fork progression with a concomitant increase in the utilization of new replication origins. Interestingly, recombinant NUCKS1 shares the same DNA binding preference as RAD51AP1, but binds to DNA with reduced affinity when compared to RAD51AP1. Our results show that NUCKS1 is a chromatin-associated protein with a role in the DNA damage response and in HR, a DNA repair pathway critical for tumor suppression.

Increased NUCKS expression is a risk factor for poor prognosis and recurrence in endometrial cancer

Nuclear ubiquitous casein and cyclin-dependent kinases substrate (NUCKS) was reported to function as a potential biomarker in various tumors. Thus, we aimed to explore the expression of NUCKS in endometrial cancer (EC) and its clinical significance using quantitative real-time PCR (qRT-PCR) and immunohistochemistry (IHC). qRT-PCR results showed that NUCKS mRNA expression gradually elevated from normal endometrium to atypical endometrial hyperplasia, and to EC (P < 0.05 between each group). NUCKS overexpression was strongly associated with FIGO stage (P = 0.002), histologic grade (P = 0.029), lympho-vascular space involvement (P = 0.014), lymph node metastasis (P = 0.019), and recurrence (P < 0.001). Cox multivariate analysis revealed that NUCKS overexpression was an independent factor for overall survival and recurrence-free survival (P < 0.001 for both). Multivariate logistic regression suggested that recurrence was independently correlated with NUCKS overexpresion (P = 0.039), FIGO stage (P = 0.002), and lymph node metastasis (P = 0.002). In summary, NUCKS overexpression may function as a potential biomarker for prognosis especially for recurrence in ECs.

NUCKS: a potential biomarker in cancer and metabolic disease

Nuclear, casein kinase and cyclin-dependent kinase substrate (NUCKS), a protein similar to the HMG (high-mobility group) protein family, is one of the most modified proteins in the mammalian proteome. Although very little is known about the biological roles of NUCKS, emerging clinical evidence suggests that this protein can be a biomarker and therapeutic target in various human ailments, including several types of cancer. An inverse correlation between NUCKS protein levels and body mass index in humans has also been observed. Depletion of NUCKS in mice has been reported to lead to obesity and impaired glucose homoeostasis. Genome-wide genomic and proteomic approaches have revealed that NUCKS is a chromatin regulator that affects transcription. The time is now ripe for further understanding of the role of this novel biomarker of cancer and the metabolic syndrome, and how its sundry modifications can affect its function. Such studies could reveal how NUCKS could be a link between physiological cues and human ailments.

Sclerosing adenosis as a predictor of breast cancer bilaterality and multicentricity

Breast cancer is occasionally complicated by sclerosing adenosis (SA). Although both lesions usually originate in the terminal duct lobular unit, their pathogenetic relationship has not yet been elucidated. The present study analyzed 63 breast cancer patients with SA (involving a total of 75 breasts) to clarify if coexisting SA increased the frequency of multicentric breast cancer or not. Using the topographical classification proposed in our previous study, breast cancers with SA were classified into the following three types: type A (n = 22), cancer area was completely surrounded by the SA; type B (n = 26), cancer area partially overlapped the SA; and type C (n = 27), cancer area was located separate from the SA. Breast cancers with SA had a significant (P < 0.001) increase in frequency of harboring bilateral and multicentric cancers [17 of 63 (27%) and 15 of 63 (24%), respectively] when compared to breast cancer patients without SA, regardless of topographical type. Breast cancers with SA were less invasive (P < 0.001), of lower histological grade (P = 0.034), and had similar frequency of estrogen receptor-positive (P = 0.21) and HER2-positive (P = 0.74) tumors. In conclusion, contralateral and ipsilateral multicentric breast cancers occurred at a higher frequency in those with SA. Our data suggest that SA is, in addition to lobular neoplasia, a predictor of multicentric breast cancers.

Identification of AMP-activated protein kinase targets by a consensus sequence search of the proteome

Background

AMP-activated protein kinase (AMPK) is a heterotrimeric serine/threonine protein kinase that is activated by cellular perturbations associated with ATP depletion or stress. While AMPK modulates the activity of a variety of targets containing a specific phosphorylation consensus sequence, the number of AMPK targets and their influence over cellular processes is currently thought to be limited.

Results

We queried the human and the mouse proteomes for proteins containing AMPK phosphorylation consensus sequences. Integration of this database into Gaggle software facilitated the construction of probable AMPK-regulated networks based on known and predicted molecular associations. In vitro kinase assays were conducted for preliminary validation of 12 novel AMPK targets across a variety of cellular functional categories, including transcription, translation, cell migration, protein transport, and energy homeostasis. Following initial validation, pathways that include NAD synthetase 1 (NADSYN1) and protein kinase B (AKT2) were hypothesized and experimentally tested to provide a mechanistic basis for AMPK regulation of cell migration and maintenance of cellular NAD⁺ concentrations during catabolic processes.

Conclusions

This study delineates an approach that encompasses both in silico procedures and in vitro experiments to produce testable hypotheses for AMPK regulation of cellular processes.

Electronic supplementary material

The online version of this article (doi:10.1186/s12918-015-0156-0) contains supplementary material, which is available to authorized users.

NUCKS1, a novel Tat coactivator, plays a crucial role in HIV-1 replication by increasing Tat-mediated viral transcription on the HIV-1 LTR promoter

BACKGROUND

Human immunodeficiency virus-1 (HIV-1) Tat protein plays an essential role in HIV gene transcription from the HIV-1 long terminal repeat (LTR) and replication. Transcriptional activity of Tat is modulated by several host factors, but the mechanism responsible for Tat regulation by host factors is not understood fully.

RESULTS

Using a yeast two-hybrid screening system, we identified Nuclear ubiquitous casein and cyclin-dependent kinase substrate 1 (NUCKS1) as a novel Tat-interacting partner. Here, we report its function as a positive regulator of Tat. In a coimmunoprecipitation assay, HIV-1 Tat interacted sufficiently with both endogenous and ectopically expressed NUCKS1. In a reporter assay, ectopic expression of NUCKS1 significantly increased Tat-mediated transcription of the HIV-1 LTR, whereas knockdown of NUCKS1 by small interfering RNA diminished Tat-mediated transcription of the HIV-1 LTR. We also investigated which mechanism contributes to NUCKS1-mediated Tat activation. In a chromatin immunoprecipitation assay (ChIP), knockdown of NUCKS1 interrupted the accumulation of Tat in the transactivation-responsive (TAR) region on the LTR, which then led to suppression of viral replication. However, NUCKS1 expression did not increase Tat nuclear localization and interaction with Cyclin T1. Interestingly, the NUCKS1 expression level was lower in latently HIV-1-infected cells than in uninfected parent cells. Besides, expression level of NUCKS1 was markedly induced, which then facilitated HIV-1 reactivation in latently infected cells.

CONCLUSION

Taken together, our data demonstrate clearly that NUCKS1 is a novel Tat coactivator that is required for Tat-mediated HIV-1 transcription and replication, and that it may contribute to HIV-1 reactivation in latently HIV-1 infected cells.

NUCKS is a positive transcriptional regulator of insulin signaling

Although much is known about the molecular players in insulin signaling, there is scant information about transcriptional regulation of its key components. We now find that NUCKS is a transcriptional regulator of the insulin signaling components, including the insulin receptor (IR). Knockdown of NUCKS leads to impaired insulin signaling in endocrine cells. NUCKS knockout mice exhibit decreased insulin signaling and increased body weight/fat mass along with impaired glucose tolerance and reduced insulin sensitivity, all of which are further exacerbated by a high-fat diet (HFD). Genome-wide ChIP-seq identifies metabolism and insulin signaling as NUCKS targets. Importantly, NUCKS is downregulated in individuals with a high body mass index and in HFD-fed mice, and conversely, its levels increase upon starvation. Altogether, NUCKS is a physiological regulator of energy homeostasis and glucose metabolism that works by regulating chromatin accessibility and RNA polymerase II recruitment to the promoters of IR and other insulin pathway modulators.

NUCKS1 overexpression is a novel biomarker for recurrence-free survival in cervical squamous cell carcinoma

Nuclear casein kinase and cyclin-dependent kinase substrate 1 (NUCKS1) is overexpressed in various cancer tissues and may therefore contribute to oncogenesis. However, the status of NUCKS1 expression in cervical squamous cell carcinoma (CSCC) remains unknown. Immunohistochemistry was used to determine the expression of NUCKS1 protein in 30 cervical intraepithelial neoplasias (CINs) and 125 CSCCs compared with 20 normal cervical specimens. The correlationships of NUCKS1 protein overexpression with the clinicopathologic characteristics and clinical outcomes in patients with CSCC were analysed. The status of NUCKS1 expression was negative or weak in normal tissues, but high in 21 (70.0 %) CINs and in 44 (35.2 %) CSCCs. NUCKS1 overexpression was associated with advanced International Federation of Gynaecology and Obstetrics stage (P = 0.016), poor histologic grade (P = 0.040), large tumour size (P = 0.016), parametrial involvement (P = 0.025), deep stromal infiltration (P = 0.043), lymph node metastasis (P = 0.034) and recurrence (P < 0.001). Multivariate analysis suggested that NUCKS1 overexpression was an independent factor for recurrence-free survival (RFS) (hazard ratio, 2.193; 95 % confidence interval, 1.060 to 4.535; P = 0.034). In conclusion, NUCKS1 overexpression may be associated with tumour progression and recurrence in CSCCs and may thus serve as a new molecular marker for the prediction of RFS in these patients.

Dynamic expression of the vertebrate-specific protein Nucks during rodent embryonic development

The nuclear casein kinase and cyclin-dependent kinase substrate 1 (NUCKS) is a highly phosphorylated nuclear protein that is overexpressed in many types of cancer. The flexibility of NUCKS and its extensive posttranslational modifications indicate that it is multifunctional, and its expression in most cell types suggests a housekeeping function. However, spatiotemporal expression of the Nucks protein during rodent development has not been reported. Thus, we investigated the expression of both the Nucks mRNA and protein during rat and mouse development by immunohistochemistry, in situ hybridization, Western immunoblotting, and reverse-transcription PCR analysis. We also used BLAST analysis against expressed sequence tag databases to determine whether a NUCKS homologue is expressed in invertebrate organisms. We found that Nucks expression increased during the initial stages of embryonic development, and then gradually decreased until birth in all tissues except the nervous tissue and muscle fibers. Interestingly, the expression of Nucks was very strong in migrating neural crest cells at E13.5 and ectoderm-derived tissues. In most tissues analyzed, the levels of Nucks correlated with the levels of Bax and activated caspase-3, which are indicative of apoptosis. Moreover, Nucks was upregulated very early during neuronal apoptosis in vitro. Expression analysis revealed that no transcript with close homology to the Nucks gene was present in invertebrates. The expression of Nucks in both proliferating and quiescent cells and its correlation with Bax levels and apoptosis strongly suggest that Nucks plays complex roles in cell homeostasis. Furthermore, the lack of homology in invertebrate organisms indicates a specific role for Nucks in vertebrate embryogenesis.

RGD binding to integrin alphavbeta3 affects cell motility and adhesion in primary human breast cancer cultures

Integrins mediate cell adhesion to the extracellular matrix. Integrin alphavbeta3 recognizes the RGD motif as a ligand-binding site and has been associated with high malignant potential in breast cancer cells, signaling the onset of widespread metastasis. In recent years, several antagonists of integrin alphavbeta3, including RGD peptides, have been used as potential anti-cancer agents. In the present work, the effect of the linear RGD hexapeptide GRGDSP was studied, for the first time, on breast tumor explants, as well as on well-spread human breast cancer cells from primary cultures, using the explant technique, to clarify the role of this peptide in the suppression of breast cancer cell migration. The results showed that incubation of breast tumor explants with RGD peptide at the beginning of culture development inhibited completely the migration of cancer cells out of the tissue fragment as revealed by electron microscopy. RGD incubation of well-spread breast cancer cells from primary culture resulted in rounding and shrinkage of the cells accompanied by altered distribution of integrin alphavbeta3 and concomitant F-actin cytoskeletal disorganization, as revealed by immunofluorescence. Electron immunocytochemistry showed aggregation of integrin alphavbeta3 at the cell periphery and its detection in noncoated vesicles. However, Western immunoblotting showed no change in beta3 subunit expression, despite the altered distribution of the integrin alphavbeta3. In light of the above, it appears that the RGD peptide plays an important role in the modulation of cell motility and in the perturbation of cell attachment affecting the malignant potential of breast cancer cells in primary cultures.

Identification of NUCKS1 as a colorectal cancer prognostic marker through integrated expression and copy number analysis

We identified a novel prognostic biomarker for the distant metastasis of colorectal cancer (CRC) using comprehensive combined copy number and gene expression analyses. Expression of mRNA in CRC tissue was profiled in 115 patients using an Affymetrix Gene Chip, and copy number profiles were generated for 122 patients using an Affymetrix 250K Sty array. Genes showing both upregulated expression and copy number gains in cases involving distant CRC metastasis were extracted as candidate biomarkers. Expression of the candidate gene mRNA was validated in 86 patients using quantitative reverse transcription polymerase chain reaction assays. Expression of the protein encoded by the candidate gene was assessed using immunohistochemical staining of tissue from 269 patients. The relationship between protein expression and clinicopathologic features was also examined. Following combined copy number and gene expression analyses, three genes linked to distant metastasis of CRC were extracted as candidate biomarkers. The expression of NUCKS1, reportedly overexpressed in several cancers other than CRC, was significantly higher in CRC tissue than in normal tissue. Overexpression of the NUCKS1 protein in CRC cells was found to be associated with significantly worse overall survival and relapse-free survival, indicating that NUCKS1 is an independent risk factor for CRC recurrence. The overexpression of NUCKS1 in cancer cells could be used as a CRC prognostic marker and might also be a target for treatment of this disease.