NBPF1, a tumor suppressor candidate in neuroblastoma, exerts growth inhibitory effects by inducing a G1 cell cycle arrest

Transcriptome analysis displays new molecular insights into the mechanisms of action of Mebendazole in gastric cancer cells

Gastric cancer (GC) is a common cancer worldwide. Therefore, searching for effective treatments is essential, and drug repositioning can be a promising strategy to find new potential drugs for GC therapy. For the first time, we sought to identify molecular alterations and validate new mechanisms related to Mebendazole (MBZ) treatment in GC cells through transcriptome analysis using microarray technology. Data revealed 1066 differentially expressed genes (DEGs), of which 345 (2.41 %) genes were upregulated, 721 (5.04 %) genes were downregulated, and 13,231 (92.54 %) genes remained unaltered after MBZ exposure. The overexpressed genes identified were CCL2, IL1A, and CDKN1A. In contrast, the H3C7, H3C11, and H1-5 were the top 3 underexpressed genes. Gene set enrichment analysis (GSEA) identified 8 pathways significantly overexpressed in the treated group (p < 0.05 and FDR<0.25). The validation of the expression of top desregulated genes by RT-qPCR confirmed the transcriptome results, where MBZ increased the CCL2, IL1A, and CDKN1A and reduced the H3C7, H3C11, and H1-5 transcript levels. Expression analysis in samples from TCGA databases correlated that the lower ILI1A and higher H3C11 and H1-5 gene expression are associated with decreased overall survival rates in patients with GC, indicating that MBZ treatment can improve the prognosis of patients. Thus, the data demonstrated that the drug MBZ alters the transcriptome of the AGP-01 lineage, mainly modulating the expression of histone proteins and inflammatory cytokines, indicating a possible epigenetic and immunological effect on tumor cells, these findings highlight new mechanisms of action related to MBZ treatment. Additional studies are still needed to better clarify the epigenetic and immune mechanism of MBZ in the therapy of GC.

Neuroblastoma Breakpoint Family 3mer Higher Order Repeats/Olduvai Triplet Pattern in the Complete Genome of Human and Nonhuman Primates and Relation to Cognitive Capacity

BACKGROUND/OBJECTIVES

The ~1.6 kb NBPF repeat units in neuroblastoma breakpoint family (NBPF) genes are specific to humans and are associated with cognitive capacity in higher primates. While the number of NBPF monomers/Olduvai sequences in humans is approximately 2-3 times greater than in great apes, the difference in copy number values of canonical NBPF 3mer Higher-order repeats (HORs)/Olduvai triplets between humans and great apes is substantially larger. This study aims to analyze the organization and evolutionary significance of NBPF 3mer HORs/Olduvai triplets in fully sequenced primate genomes.

METHODS

We applied the global repeat map (GRM) algorithm to identify canonical and variant NBPF 3mer HORs/Olduvai triplets in the complete genomes of humans, chimpanzees, gorillas, and orangutans. The resulting monomer arrays were analyzed using the GRMhor algorithm to generate detailed schematic representations of NBPF HOR organization.

RESULTS

The analysis reveals a distinct difference in NBPF-related patterns among these primates, particularly in the number of tandemly organized canonical 3mer HORs/Olduvai triplets: 61 tandemly organized canonical NBPF 3mer HORs/Olduvai triplets in humans, compared to 0 in chimpanzees and orangutans, and 9 in gorillas. When considering only tandemly organized 3mer HORs/Olduvai triplets with more than three copies, the numbers adjust to 36 in humans and 0 in great apes. Furthermore, the divergence between individual NBPF monomers in humans and great apes is twice as high as that observed within great apes.

CONCLUSIONS

These findings support the hypothesis that the tandem organization of NBPF 3mer HORs/Olduvai triplets plays a crucial role in enhancing cognitive capacity in humans compared to great apes, potentially providing a significant evolutionary advantage. This effect complements the impact of the increased number of individual NBPF monomers/Olduvai sequences, together contributing to a synergistic amplification effect.

The emerging role of breast cancer derived extracellular vesicles-mediated intercellular communication in ovarian cancer progression and metastasis

Breast cancer is one of the most occurring cancer types in women worldwide and metastasizes to several organs such as bone, lungs, liver, brain, and ovaries. Extracellular vesicles (EVs) mediate intercellular signaling which has a profound effect on tumor development and metastasis. Recent developments in the field of EVs provide an opportunity to investigate the roles of EVs released from tumor cells in metastasis. In this study, we compared the effects of metastatic breast cancer-derived EVs on both nonluteinized granulosa HGrC1 and ovarian cancer OVCAR-3 cells in terms of proliferation, invasion, apoptosis, and gene expression levels. EVs were isolated from the culture medium of metastatic breast cancer cell line MDA-MB-231 by ultracentrifugation. Cell proliferation, apoptosis, cell cycle, invasion, and cellular uptake analysis were performed to clarify the roles of tumor-derived EVs in both cells. 6.85 × 108 nanoparticles of BCD-EVs were markedly increased cell proliferation as well as invasion capacity. Exposing the cells with BCD-EVs for 24 h, resulted in an accumulation of both cells in G2/M phase as determined by flow cytometry. The apoptosis assay results were consistent with cell proliferation and cell cycle results. The uptake of the BCD-EVs was efficiently internalized by both cells. In addition, marked variations in fatty acid composition between cells were observed. BCD-EVs appeared new fatty acids in HGrC1. Besides, BCD-EVs upregulated epithelial-mesenchymal transition (EMT) and proliferation-related genes. In conclusion, an environment of tumor-derived EVs changes the cellular phenotype of cancer and noncancerous cells and may lead to tumor progression and metastasis.

Tandem NBPF 3mer HORs (Olduvai triplets) in Neanderthal and two novel HOR tandem arrays in human chromosome 1 T2T-CHM13 assembly

It is known that the ~ 1.6 kb Neuroblastoma BreakPoint Family (NBPF) repeats are human specific and contributing to cognitive capabilities, with increasing frequency in higher order repeat 3mer HORs (Olduvai triplets). From chimpanzee to modern human there is a discontinuous jump from 0 to ~ 50 tandemly organized 3mer HORs. Here we investigate the structure of NBPF 3mer HORs in the Neanderthal genome assembly of Pääbo et al., comparing it to the results obtained for human hg38.p14 chromosome 1. Our findings reveal corresponding NBPF 3mer HOR arrays in Neanderthals with slightly different monomer structures and numbers of HOR copies compared to humans. Additionally, we compute the NBPF 3mer HOR pattern for the complete telomere-to-telomere human genome assembly (T2T-CHM13) by Miga et al., identifying two novel tandem arrays of NBPF 3mer HOR repeats with 5 and 9 NBPF 3mer HOR copies. We hypothesize that these arrays correspond to novel NBPF genes (here referred to as NBPFA1 and NBPFA2). Further improving the quality of the Neanderthal genome using T2T-CHM13 as a reference would be of great interest in determining the presence of such distant novel NBPF genes in the Neanderthal genome and enhancing our understanding of human evolution.

In Silico Pipeline to Identify Tumor-Specific Antigens for Cancer Immunotherapy Using Exome Sequencing Data

Tumor-specific antigens or neoantigens are peptides that are expressed only in cancer cells and not in healthy cells. Some of these molecules can induce an immune response, and therefore, their use in immunotherapeutic strategies based on cancer vaccines has been extensively explored. Studies based on these approaches have been triggered by the current high-throughput DNA sequencing technologies. However, there is no universal nor straightforward bioinformatic protocol to discover neoantigens using DNA sequencing data. Thus, we propose a bioinformatic protocol to detect tumor-specific antigens associated with single nucleotide variants (SNVs) or "mutations" in tumoral tissues. For this purpose, we used publicly available data to build our model, including exome sequencing data from colorectal cancer and healthy cells obtained from a single case, as well as frequent human leukocyte antigen (HLA) class I alleles in a specific population. HLA data from Costa Rican Central Valley population was selected as an example. The strategy included three main steps: (1) pre-processing of sequencing data; (2) variant calling analysis to detect tumor-specific SNVs in comparison with healthy tissue; and (3) prediction and characterization of peptides (protein fragments, the tumor-specific antigens) derived from the variants, in the context of their affinity with frequent alleles of the selected population. In our model data, we found 28 non-silent SNVs, present in 17 genes in chromosome one. The protocol yielded 23 strong binders peptides derived from the SNVs for frequent HLA class I alleles for the Costa Rican population. Although the analyses were performed as an example to implement the pipeline, to our knowledge, this is the first study of an in silico cancer vaccine using DNA sequencing data in the context of the HLA alleles. It is concluded that the standardized protocol was not only able to identify neoantigens in a specific but also provides a complete pipeline for the eventual design of cancer vaccines using the best bioinformatic practices.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43657-022-00084-9.

Characteristic gene prognostic model of type 1 diabetes mellitus via machine learning strategy

The present study was designed to detect possible biomarkers associated with Type 1 diabetes mellitus (T1DM) incidence in an effort to develop novel treatments for this condition. Three mRNA expression datasets of peripheral blood mononuclear cells (PBMCs) were obtained from the GEO database. Differentially expressed genes (DEGs) between T1DM patients and healthy controls were identified by Limma package in R, and using the DEGs to conduct GO and DO pathway enrichment. The LASSO-SVM were used to screen the hub genes. We performed immune correlation analysis of hub genes and established a T1DM prognosis model. CIBERSORT algorithm was used to identify the different immune cells in distribution between T1DM and normal samples. The correlation of the hub genes and immune cells was analyzed by Spearman. ROC curves were used to assess the diagnostic value of genes in T1DM. A total of 60 immune related DEGs were obtained from the T1DM and normal samples. Then, DEGs were further screened to obtain 3 hub genes, ANP32A-IT1, ESCO2 and NBPF1. CIBERSORT analysis revealed the percentage of immune cells in each sample, indicating that there was significant difference in monocytes, T cells CD8+, gamma delta T cells, naive CD4+ T cells and activated memory CD4+ T cells between T1DM and normal samples. The area under curve (AUC) of ESCO2, ANP32A-IT1 and NBPF1 were all greater than 0.8, indicating that these three genes have high diagnostic value for T1DM. Together, the findings of these bioinformatics analyses thus identified key hub genes associated with T1DM development.

Patterns of Somatic Variants in Colorectal Adenoma and Carcinoma Tissue and Matched Plasma Samples from the Hungarian Oncogenome Program

Analysis of circulating cell-free DNA (cfDNA) of colorectal adenoma (AD) and cancer (CRC) patients provides a minimally invasive approach that is able to explore genetic alterations. It is unknown whether there are specific genetic variants that could explain the high prevalence of CRC in Hungary. Whole-exome sequencing (WES) was performed on colon tissues (27 AD, 51 CRC) and matched cfDNAs (17 AD, 33 CRC); furthermore, targeted panel sequencing was performed on a subset of cfDNA samples. The most frequently mutated genes were APC, KRAS, and FBN3 in AD, while APC, TP53, TTN, and KRAS were the most frequently mutated in CRC tissue. Variants in KRAS codons 12 (AD: 8/27, CRC: 11/51 (0.216)) and 13 (CRC: 3/51 (0.06)) were the most frequent in our sample set, with G12V (5/27) dominance in ADs and G12D (5/51 (0.098)) in CRCs. In terms of the cfDNA WES results, tumor somatic variants were found in 6/33 of CRC cases. Panel sequencing revealed somatic variants in 8 out of the 12 enrolled patients, identifying 12/20 tumor somatic variants falling on its targeted regions, while WES recovered only 20% in the respective regions in cfDNA of the same patients. In liquid biopsy analyses, WES is less efficient compared to the targeted panel sequencing with a higher coverage depth that can hold a relevant clinical potential to be applied in everyday practice in the future.

Molecular underpinnings of exceptional response in primary malignant melanoma of the esophagus to anti-PD-1 monotherapy

BACKGROUND

Accumulating data suggest that mucosal melanoma, well known for its poor response to immune checkpoint blockade (ICB) and abysmal prognosis, is a heterogeneous subtype of melanoma with distinct genomic and clinical characteristics between different anatomic locations of the primary lesions. Primary malignant melanoma of the esophagus (PMME) is a rare, highly aggressive disease with a poorer prognosis compared with that of non-esophageal mucosal melanoma (NEMM). In this study, we retrospectively analyzed the efficacy of anti-programmed death (PD)-1 in patients with PMME and explored its molecular basis.

METHODS

The response and survival of patients with PMME and NEMM under anti-PD-1 monotherapy were retrospectively analyzed. To explore the molecular mechanisms of the difference in therapeutic efficacy between PMME and NEMM, we performed genomic analysis, bulk RNA sequencing, and multiplex immunohistochemistry staining.

RESULTS

We found that PMME (n=28) responded better to anti-PD-1 treatment than NEMM (n=64), with a significantly higher objective response rate (33.3% (95% CI 14.3% to 52.3%) vs 6.6% (95% CI 0.2% to 12.9%)) and disease control rate (74.1% (95% CI 56.4% to 91.7%) vs 37.7% (95% CI 25.2% to 50.2%)). Genomic sequencing analysis revealed that the genomic aberration landscape of PMME predominated in classical cancer driver genes, with approximately half of PMME cases harboring mutations in BRAF, N/KRAS, and NF1. In contrast, most NEMM cases were triple wild-type. Transcriptome analysis revealed that, compared with NEMM, PMME displayed more significant proliferation and inflammatory features with higher expression of genes related to antigen presentation and differentiation, and a less immunosuppressive signature with lower expression of inhibitory immune checkpoints and dedifferentiation-related genes. The multiplex immunohistochemical analysis also demonstrated higher CD8⁺ T-cell infiltration in PMME than in NEMM.

CONCLUSIONS

PMME is an outlier of mucosal melanoma showing a malicious phenotype but a particularly high response rate to ICB because of its distinct molecular characteristics. Patient stratification based on anatomic origin can facilitate clinical decision-making in patients with mucosal melanoma following the verification of our results in future prospective studies.

A systematic view of computational methods for identifying driver genes based on somatic mutation data

Abnormal changes of driver genes are serious for human health and biomedical research. Identifying driver genes, exactly from enormous genes with mutations, promotes accurate diagnosis and treatment of cancer. A lot of works about uncovering driver genes have been developed over the past decades. By analyzing previous works, we find that computational methods are more efficient than traditional biological experiments when distinguishing driver genes from massive data. In this study, we summarize eight common computational algorithms only using somatic mutation data. We first group these methods into three categories according to mutation features they apply. Then, we conclude a general process of nominating candidate cancer driver genes. Finally, we evaluate three representative methods on 10 kinds of cancer derived from The Cancer Genome Atlas Program and five Chinese projects from the International Cancer Genome Consortium. In addition, we compare results of methods with various parameters. Evaluation is performed from four perspectives, including CGC, OG/TSG, Q-value and QQQuantile-Quantileplot. To sum up, we present algorithms using somatic mutation data in order to offer a systematic view of various mutation features and lay the foundation of methods based on integration of mutation information and other types of data.

SMARCB1 deletion in atypical teratoid rhabdoid tumors results in human endogenous retrovirus K (HML-2) expression

Atypical Teratoid Rhabdoid Tumor (AT/RT) is a rare pediatric central nervous system cancer often characterized by deletion or mutation of SMARCB1, a tumor suppressor gene. In this study, we found that SMARCB1 regulates Human Endogenous Retrovirus K (HERV-K, subtype HML-2) expression. HML-2 is a repetitive element scattered throughout the human genome, encoding several intact viral proteins that have been associated with stem cell maintenance and tumorigenesis. We found HML-2 env expression in both the intracellular and extracellular compartments in all AT/RT cell lines (n = 4) and in 95% of AT/RT patient tissues (n = 37) evaluated. SMARCB1 knock-down in neural stem cells (NSCs) led to an upregulation of HML-2 transcription. We found that SMARCB1 binds adjacent to the HML-2 promoter, repressing its transcription via chromatin immunoprecipitation; restoration of SMARCB1 expression in AT/RT cell lines significantly downregulated HML-2 expression. Further, targeted downregulation of HML-2 transcription via CRISPR-dCas9 coupled with suppressor proteins led to cellular dispersion, decreased proliferation, and cell death in vitro. HML-2 knock-down with shRNA, siRNA, and CRISPR-dCas9 significantly decreased Ras expression as measured by qRT-PCR, suggesting that HML-2 modulates MAPK/ERK signaling in AT/RT cells. Overexpression of NRAS was sufficient to restore cellular proliferation, and MYC, a transcription factor downstream of NRAS, was bound to the HERV-K LTR significantly more in the absence of SMARCB1 expression in AT/RT cells. We show a mechanism by which these undifferentiated tumors remain pluripotent, and we demonstrate that their formation is aided by aberrant HML-2 activation, which is dependent on SMARCB1 and its interaction with MYC.

Deciphering molecular heterogeneity in pediatric AML using a cancer vs. normal transcriptomic approach

BACKGROUND

Still 30-40% of pediatric acute myeloid leukemia (pedAML) patients relapse. Delineation of the transcriptomic profile of leukemic subpopulations could aid in a better understanding of molecular biology and provide novel biomarkers.

METHODS

Using microarray profiling and quantitative PCR validation, transcript expression was measured in leukemic stem cells (LSC, n = 24) and leukemic blasts (L-blast, n = 25) from pedAML patients in comparison to hematopoietic stem cells (HSCs, n = 19) and control myeloblasts (C-blast, n = 20) sorted from healthy subjects. Gene set enrichment analysis was performed to identify relevant gene set enrichment signatures, and functional protein associations were identified by STRING analysis.

RESULTS

Highly significantly overexpressed genes in LSC and L-blast were identified with a vast majority not studied in AML. CDKN1A, CFP, and CFD (LSC) and HOMER3, CTSA, and GADD45B (L-blast) represent potentially interesting biomarkers and therapeutic targets. Eleven LSC downregulated targets were identified that potentially qualify as tumor suppressor genes, with MYCT1, PBX1, and PTPRD of highest interest. Inflammatory and immune dysregulation appeared to be perturbed biological networks in LSC, whereas dysregulated metabolic profiles were observed in L-blast.

CONCLUSION

Our study illustrates the power of taking into account cell population heterogeneity and reveals novel targets eligible for functional evaluation and therapy in pedAML.

IMPACT

Novel transcriptional targets were discovered showing a significant differential expression in LSCs and blasts from pedAML patients compared to their normal counterparts from healthy controls. Deregulated pathways, including immune and metabolic dysregulation, were addressed for the first time in children, offering a deeper understanding of the molecular pathogenesis. These novel targets have the potential of acting as biomarkers for risk stratification, follow-up, and targeted therapy. Multiple LSC-downregulated targets endow tumor suppressor roles in other cancer entities, and further investigation whether hypomethylating therapy could result into LSC eradication in pedAML is warranted.

Effect of Ag nanoparticles on viability of MCF-7 and Vero cell lines and gene expression of apoptotic genes

Background

The newly emerged technology, nanotechnology, represents a promising solution for many medical and industrial problems. Random targeting, resistance, and side effects are the main disadvantages of the available cancer chemotherapy which are critical aspects needed to be managed. So the aim of the study was to suggest the nanoparticles as an alternative therapy for the available therapies through detecting the cytotoxic effect of Ag nanoparticles against cancer and normal cell lines and how they affect the apoptotic function and the genes involved.

Results

Ag NPs exhibited a killing rate of 40% in MCF-7 cells (the cancer cell model) at a concentration of 100 μg/ml with almost no effect on Vero cells (the normal cell model). Concerning the phenotypic apoptotic changes that were analyzed by Acridine orange and eosin and hematoxylin, Ag NPs caused the apoptosis and Vacuole degeneration as well as cell formation and the emergence of Necrotic cells in MCF-7 cells, whereas in the normal cell line Vero, no change appears in its phenotype.

Treating MCF-7 and Vero cells with Ag NPs upregulated the P53 and P21 gene expression in Vero cells, but their expression was downregulated in MCF-7 cells. PTEN was augmented in both MCF-7 and Vero cells compared to the control.

Conclusions

The AgNPs displayed selective effect in their cytotoxicity and both induced the apoptosis effect and might be suggested as a potential therapy since an increase in PTEN expression (up to 250-fold more compared to the control) due to the treatment with AgNPs augments the tumor suppressor effects of the PTEN.

Genomic and epigenetic aberrations of chromosome 1p36.13 have prognostic implications in malignancies

Deletions of chromosome 1p36 are common in malignancies; however, there is limited information regarding the biological and prognostic implications of 1p36 in cancer. Steroid Receptor-Associated and Regulated Protein (SRARP) is a tumor suppressor on chromosome 1p36.13 that its inactivation predicts poor cancer outcome, indicating that the 1p36.13 segment requires further studies. Therefore, a comprehensive multi-omics analysis of The Cancer Genome Atlas (TCGA), the Pan-Cancer Analysis of Whole Genomes (PCAWD), the International Cancer Genome Consortium (ICGC), and the Genomic Data Commons (GDC) Pan-Cancer datasets was conducted to investigate the prognostic implications of 1p36.13 in malignancies. This study revealed that expression and DNA methylation of multiple genes on 1p36.13 are significantly associated with survival in primary tumors and normal adjacent tissues. In addition, copy-number loss in every gene on 1p36.13 predicts poor cancer outcome. Importantly, copy-number loss and somatic mutations of chromosome 1p36.13 segment are associated with worse survival in primary tumors, and DNA hypermethylation of 1p36.13 predicts poor outcome in normal adjacent tissues. Therefore, genomic and epigenetic aberrations of chromosome 1p36.13 have promising prognostic implications in cancer.

Mutational landscape and patterns of clonal evolution in relapsed pediatric acute lymphoblastic leukemia

Relapse of acute lymphoblastic leukemia (ALL) remains a leading cause of childhood death. Prior studies have shown clonal mutations at relapse often arise from relapse-fated subclones that exist at diagnosis. However, the genomic landscape, evolutionary trajectories and mutational mechanisms driving relapse are incompletely understood. In an analysis of 92 cases of relapsed childhood ALL, incorporating multimodal DNA and RNA sequencing, deep digital mutational tracking and xenografting to formally define clonal structure, we identify 50 significant targets of mutation with distinct patterns of mutational acquisition or enrichment. CREBBP, NOTCH1, and Ras signaling mutations rose from diagnosis subclones, whereas variants in NCOR2, USH2A and NT5C2 were exclusively observed at relapse. Evolutionary modeling and xenografting demonstrated that relapse-fated clones were minor (50%), major (27%) or multiclonal (18%) at diagnosis. Putative second leukemias, including those with lineage shift, were shown to most commonly represent relapse from an ancestral clone rather than a truly independent second primary leukemia. A subset of leukemias prone to repeated relapse exhibited hypermutation driven by at least three distinct mutational processes, resulting in heightened neoepitope burden and potential vulnerability to immunotherapy. Finally, relapse-driving sequence mutations were detected prior to relapse using deep digital PCR at levels comparable to orthogonal approaches to monitor levels of measurable residual disease. These results provide a genomic framework to anticipate and circumvent relapse by earlier detection and targeting of relapse-fated clones.

Genomic characterization of vulvar squamous cell carcinoma

BACKGROUND

Despite increasing incidence, vulvar squamous cell carcinoma (VSCC) is still a rare disease. Until now, two etiological pathways have been described: a high-risk human papillomavirus (HPV)-dependent route and an HPV-independent pathway often associated with lichen sclerosus. To date, therapeutic strategies in VSCC are not influenced by molecular pathological information and therapeutic options for advanced or recurrent disease are limited.

METHODS

Whole exome sequencing of DNA, isolated from 34 VSCC samples and matched normal tissue for each individual was performed on an Illumina HiSeq4000. Short variant discovery was carried out using BWA mem and FreeBayes. Variants were annotated using ANNOVAR.

RESULTS

FIGO stages were: IB (n = 7), II (n = 11), III (n = 8), and IVA (n = 3), (n = 5 unknown). TP53 missense mutations were most commonly detected with 56% (19/34). 12/34 (35.3%) samples were HPV positive (all HPV16), HPV positivity and TP53 mutations were mutually exclusive (p < .0001). Additionally, we observed mutations in known cancer relevant genes, like NBPF1 (n = 7), MACF1 (n = 5), SYNE2 (n = 5), DOCK2 (n = 4), KMT2D (n = 4), MAP2 (n = 4), NACA (n = 4), PIK3CA (n = 4), SYNE1 (n = 4), FBWX7 (n = 3), MSH6 (n = 3), NSD1 (n = 3), POLE (n = 3), TSC2, (n = 3) and CDKN2A (n = 2), but at considerably lower frequencies. For the total cohort 1848 cancer related mutations were detected (median of 54.4 per sample).

CONCLUSIONS

The key mutation in HPV negative vulvar carcinoma affects TP53. While a multitude of cancer related mutations was detected in various samples, only few mutations recur and/or affect concurrent signaling pathways.

The Zn2+ and Ca2+ -binding S100B and S100A1 proteins: beyond the myths

The S100 genes encode a conserved group of 21 vertebrate-specific EF-hand calcium-binding proteins. Since their discovery in 1965, S100 proteins have remained enigmatic in terms of their cellular functions. In this review, we summarize the calcium- and zinc-binding properties of the dimeric S100B and S100A1 proteins and highlight data that shed new light on the extracellular and intracellular regulation and functions of S100B. We point out that S100B and S100A1 homodimers are not functionally interchangeable and that in a S100A1/S100B heterodimer, S100A1 acts as a negative regulator for the ability of S100B to bind Zn²⁺ . The Ca²⁺ and Zn²⁺ -dependent interactions of S100B with a wide array of proteins form the basis of its activities and have led to the derivation of some initial rules for S100B recognition of protein targets. However, recent findings have strongly suggested that these rules need to be revisited. Here, we describe a new consensus S100B binding motif present in intracellular and extracellular vertebrate-specific proteins and propose a new model for stable interactions of S100B dimers with full-length target proteins. A chaperone-associated function for intracellular S100B in adaptive cellular stress responses is also discussed. This review may help guide future studies on the functions of S100 proteins in general.

The N-terminal of NBPF15 causes multiple types of aggregates and mediates phase transition

The neuroblastoma breakpoint family (NBPF) consists of 24 members that play an important role in neuroblastoma and other cancers. NBPF is an evolutionarily recent gene family that encodes several repeats of Olduvai domain and an abundant N-terminal region. The function and biochemical properties of both Olduvai domain and the N-terminal region remain enigmatic. Human NBPF15 encodes a 670 AA protein consisting of six clades of Olduvai domains. In this study, we synthesized and expressed full-length NBPF15, and purified a range of NBPF15 truncations which were analyzed using dynamic light scattering (DLS), superdex200 (S200), small-angle X-ray scattering (SAXS), far-UV circular dichroism (CD) spectroscopy, transmission electron microscope (TEM), and crystallography. We found that proteins containing both the N-terminal region and Olduvai domain are heterogeneous with multiple types of aggregates, and some of them underwent a liquid-to-solid phase transition, probably because of the entanglement within the N-terminal coiled-coil. Proteins that contain only the Olduvai domain are homogeneous extended monomers, and those with the conserved clade 1 (CON1) have manifested a tendency to crystallize. We suggest that the entanglements between the mosaic disorder-ordered segments in NBPF15 N terminus have triggered the multiple types of aggregates and phase transition of NBPF15 proteins, which could be associated with Olduvai-related cognitive dysfunction diseases.

The somatic mutation landscape of Chinese Colorectal Cancer

Colorectal cancer (CRC) is the fifth leading cause of cancer-related death in China. The incidence of Chinese CRC has increased dramatically with the changes of dietary and lifestyle. However, the genetic landscape of Chinese colorectal cancer mutation is still poorly understood. In this study, we have performed whole exome-sequencing analysis of 63 CRC cases. We found that Chinese CRC were hypermutated, which were enriched in ECM-receptor interaction, antigen processing and presentation, and focal adhesion. Analysis with clinical characteristics indicated that the deficiency of CRC driver gene, FCGBP and NBPF1 conferred CRC development and was showed worse survival rates, which could be the novel regulators and, diagnostic and prognostic biomarkers for Chinese CRC. Taken together, the application of whole exome-sequencing unveiled previously unsuspected somatic mutation landscape in Chinese CRCs, which may expand the understanding of disease mechanisms and provide an alternative personalized treatment for Chinese CRC patients.

Human Papillomavirus Epitope Mimicry and Autoimmunity: The Molecular Truth of Peptide Sharing

OBJECTIVE

To define the cross-reactivity potential and the consequent autoimmunity intrinsic to viral versus human peptide sharing.

METHODS

Using human papillomavirus (HPV) infection/active immunization as a research model, the experimentally validated HPV L1 epitopes catalogued at the Immune Epitope DataBase were analyzed for peptide sharing with the human proteome.

RESULTS

The final data show that the totality of the immunoreactive HPV L1 epi-topes is mostly composed by peptides present in human proteins.

CONCLUSIONS

Immunologically, the high extent of peptide sharing between the HPV L1 epitopes and human proteins invites to revise the concept of the negative selection of self-reactive lymphocytes. Pathologically, the data highlight a cross-reactive potential for a spectrum of autoimmune diseases that includes ovarian failure, systemic lupus erythematosus (SLE), breast cancer and sudden death, among others. Therapeutically, analyzing already validated immunoreactive epitopes filters out the peptide sharing possibly exempt of self-reactivity, defines the effective potential for pathologic autoimmunity, and allows singling out peptide epitopes for safe immunotherapeutic protocols.

Methylation-regulated ZNF545 inhibits growth of the p53-mutant KYSE150 cell line by inducing p21 and Bax

The Krüppel-associated box zinc-finger protein 545 (ZNF545) was recently identified as a tumor suppressor in esophageal squamous cell carcinoma (ESCC). However, the role of ZNF545 in the tumorigenesis of esophageal cancer cells expressing loss-of-function mutant p53 has not been elucidated. In the present study, the role of ZNF545 in esophageal tumors and the p53-mutant ESCC cell line, KYSE150, was investigated. ZNF545 mRNA was significantly downregulated in tumors when compared with adjacent normal tissues. Methylated ZNF545 was detected in 76.6% of tumor tissues compared with 28.1% of adjacent normal tissues. Combined pharmacological treatment of KYSE150 cells with a demethylating reagent and deacetylase inhibitor restored the expression of ZNF545. Ectopic expression of ZNF545 activated p53 transcription and upregulated the protein expression levels of pivotal effectors p21 and Bax, which are associated with cell proliferation and apoptosis, respectively, in p53-mutant KYSE150 cells; while suppressing colony formation and inducing apoptosis. ZNF545 was therefore proposed as a potential tumor suppressor responsible for inhibiting the growth of p53-mutant ESCC cell lines. In addition, tumor-specific methylation of ZNF545 may represent an epigenetic diagnostic biomarker and a therapeutic target in patients with esophageal cancer.

Gene expression alterations of human liver cancer cells following borax exposure

Borax is a boron compound that is becoming widely recognized for its biological effects, including lipid peroxidation, cytotoxicity, genotoxicity, antioxidant activity and potential therapeutic benefits. However, it remains unknown whether exposure of human liver cancer (HepG2) cells to borax affects the gene expression of these cells. HepG2 cells were treated with 4 mM borax for either 2 or 24 h. Gene expression analysis was performed using Affymetrix GeneChip Human Gene 2.0 ST Arrays, which was followed by gene ontology analysis and pathway analysis. The clustering result was validated using reverse transcription-quantitative polymerase chain reaction. A cell proliferation assay was performed using Celigo Image Cytometer Instrumentation. Following this, 2- or 24-h exposure to borax significantly altered the expression level of a number of genes in HepG2 cells, specifically 530 genes (384 upregulated and 146 downregulated) or 1,763 genes (1,044 upregulated and 719 downregulated) compared with the control group, respectively (≥2-fold; P<0.05). Twenty downregulated genes were abundantly expressed in HepG2 cells under normal conditions. Furthermore, the growth of HepG2 cells was inhibited through the downregulation of PRUNE1, NBPF1, PPcaspase-1, UPF2 and MBTPS1 (≥1.5-fold, P<0.05). The dysregulated genes potentially serve important roles in various biological processes, including the inflammation response, stress response, cellular growth, proliferation, apoptosis and tumorigenesis/oncolysis.

Pinpointing a potential role for CLEC12B in cancer predisposition through familial exome sequencing

Predisposition to cancer is only partly understood, and thus, the contribution of still undiscovered cancer predisposing variants necessitates further research. In search of such variants, we performed exome sequencing on the germline DNA of a family with two children affected by ganglioneuroma and neuroblastoma. Applying stringent selection criteria, we identified a potential deleterious, missense mutation in CLEC12B, coding for a lectin C-type receptor that is predicted to regulate immune function. Although further screening in a larger population and functional characterization is needed, we propose CLEC12B as a candidate cancer predisposition gene.

Genetic susceptibility to neuroblastoma: current knowledge and future directions

Neuroblastoma, a malignancy of the developing peripheral nervous system that affects infants and young children, is a complex genetic disease. Over the past two decades, significant progress has been made toward understanding the genetic determinants that predispose to this often lethal childhood cancer. Approximately 1-2% of neuroblastomas are inherited in an autosomal dominant fashion and a combination of co-morbidity and linkage studies has led to the identification of germline mutations in PHOX2B and ALK as the major genetic contributors to this familial neuroblastoma subset. The genetic basis of "sporadic" neuroblastoma is being studied through a large genome-wide association study (GWAS). These efforts have led to the discovery of many common susceptibility alleles, each with modest effect size, associated with the development and progression of sporadic neuroblastoma. More recently, next-generation sequencing efforts have expanded the list of potential neuroblastoma-predisposing mutations to include rare germline variants with a predicted larger effect size. The evolving characterization of neuroblastoma's genetic basis has led to a deeper understanding of the molecular events driving tumorigenesis, more precise risk stratification and prognostics and novel therapeutic strategies. This review details the contemporary understanding of neuroblastoma's genetic predisposition, including recent advances and discusses ongoing efforts to address gaps in our knowledge regarding this malignancy's complex genetic underpinnings.

iCopyDAV: Integrated platform for copy number variations-Detection, annotation and visualization

Discovery of copy number variations (CNVs), a major category of structural variations, have dramatically changed our understanding of differences between individuals and provide an alternate paradigm for the genetic basis of human diseases. CNVs include both copy gain and copy loss events and their detection genome-wide is now possible using high-throughput, low-cost next generation sequencing (NGS) methods. However, accurate detection of CNVs from NGS data is not straightforward due to non-uniform coverage of reads resulting from various systemic biases. We have developed an integrated platform, iCopyDAV, to handle some of these issues in CNV detection in whole genome NGS data. It has a modular framework comprising five major modules: data pre-treatment, segmentation, variant calling, annotation and visualization. An important feature of iCopyDAV is the functional annotation module that enables the user to identify and prioritize CNVs encompassing various functional elements, genomic features and disease-associations. Parallelization of the segmentation algorithms makes the iCopyDAV platform even accessible on a desktop. Here we show the effect of sequencing coverage, read length, bin size, data pre-treatment and segmentation approaches on accurate detection of the complete spectrum of CNVs. Performance of iCopyDAV is evaluated on both simulated data and real data for different sequencing depths. It is an open-source integrated pipeline available at https://github.com/vogetihrsh/icopydav and as Docker’s image at http://bioinf.iiit.ac.in/icopydav/.

Expression and prognostic significance of cyclin-dependent kinase inhibitor 1A in patients with resected gastric adenocarcinoma

Cyclin-dependent kinase inhibitor 1A (CDKN1A) is an important cell cycleregulator, and has been identified to exhibit aberrant expression in various types of cancer tissues. However, the association between CDKN1A expression level and prognosis in patients with resected gastric adenocarcinoma (RGA) requires additional elucidation. In the present study, the CDKN1A expression profile in RGA tissues obtained from 217 patients were analyzed using immunohistochemistry. Its prognostic significance was evaluated by using the χ² test, Kaplan-Meier curves and the log-rank test, and a multivariate Cox model analysis, during a median follow-up time of 51 months. The results demonstrated that CDKN1A expression was significantly correlated with lymph node metastasis (LNM; P=0.001), recurrence (P<0.001) and overall survival (OS; P<0.001). In addition, the recurrence-free survival (RFS) and OS times were significantly shorter in patients with low CDKN1A expression compared with those with high CDKN1A expression (RFS, 20 months vs. 69 months, P<0.001; and OS, 32 months vs. 70 months, P<0.001, respectively). Multivariate analysis additionally confirmed that low CDKN1A expression was significantly correlated with an increased risk of LNM (P=0.001), recurrence (P<0.001) and mortality (P<0.001). Therefore, these data suggest that low expression of CDKN1A has independent prognostic significance indicative of tumor progression and poor survival in patients with RGA. Evaluation of CDKN1A expression may assist in determining prognosis in patients with RGA.

QuaDMutEx: quadratic driver mutation explorer

BACKGROUND

Somatic mutations accumulate in human cells throughout life. Some may have no adverse consequences, but some of them may lead to cancer. A cancer genome is typically unstable, and thus more mutations can accumulate in the DNA of cancer cells. An ongoing problem is to figure out which mutations are drivers - play a role in oncogenesis, and which are passengers - do not play a role. One way of addressing this question is through inspection of somatic mutations in DNA of cancer samples from a cohort of patients and detection of patterns that differentiate driver from passenger mutations.

RESULTS

We propose QuaDMutEx, a method that incorporates three novel elements: a new gene set penalty that includes non-linear penalization of multiple mutations in putative sets of driver genes, an ability to adjust the method to handle slow- and fast-evolving tumors, and a computationally efficient method for finding gene sets that minimize the penalty, through a combination of heuristic Monte Carlo optimization and exact binary quadratic programming. Compared to existing methods, the proposed algorithm finds sets of putative driver genes that show higher coverage and lower excess coverage in eight sets of cancer samples coming from brain, ovarian, lung, and breast tumors.

CONCLUSIONS

Superior ability to improve on both coverage and excess coverage on different types of cancer shows that QuaDMutEx is a tool that should be part of a state-of-the-art toolbox in the driver gene discovery pipeline. It can detect genes harboring rare driver mutations that may be missed by existing methods. QuaDMutEx is available for download from https://github.com/bokhariy/QuaDMutEx under the GNU GPLv3 license.

NBPF7 promotes the proliferation of α-catenin-knockdown HaCaT cells via functional interaction with the NF-κB pathway

Loss of key components that form cell-cell adherens junctions, such as α-catenin, triggers severe epidermal hyperproliferation. However, the underlying molecular mechanisms remain largely unknown. We report here that neuroblastoma breakpoint family (NBPF) genes are upregulated and that NBPF7 specifically promotes cellular proliferation of α-catenin-silenced HaCaT cells through functional linkage with the NF-κB pathway. Genome-wide profiling of HaCaT cells shows that NBPF genes are upregulated following α-catenin knockdown. Data from western blot analyses are consistent with the activation of the NF-κB pathway as well as increased expression of NBPF7 by α-catenin knockdown. Co-immunoprecipitation assays indicate that NBPF7 could be detected in endogenous activated NF-κB immunoprecipitates. Immunoflurence analyses demonstrate that NBPF7 co-localizes with activated NF-κB in the nucleus after α-catenin silencing. Moreover, inhibition of NBPF7 decreases the proliferation of HaCaT cells and abolishes the enhanced proliferation associated with α-catenin knockdown in HaCaT cells. These results indicate that NBPF7 plays a key role in the α-catenin signaling pathway that regulates cell proliferation of keratinocytes. Our findings suggest that the classical NF-κB pathway plays a critical role in cellular proliferation and that NBPF7 is a functional mediator for α-catenin in the regulation of keratinocyte growth.

Identification of hub genes and pathways associated with bladder cancer based on co-expression network analysis

The aim of the present study was to identify hub genes and signaling pathways associated with bladder cancer (BC) utilizing centrality analysis and pathway enrichment analysis. The differentially expressed genes (DEGs) were screened from the ArrayExpress database between normal subjects and BC patients. Co-expression networks of BC were constructed using differentially co-expressed genes and links, and hub genes were investigated by degree centrality analysis of co-expression networks in BC. The enriched signaling pathways were investigated by Kyoto Encyclopedia of Genes and Genomes database analysis based on the DEGs. The hub gene expression in BC tissues was validated using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blotting. A total of 329 DEGs were screened, including 147 upregulated and 182 downregulated genes. The co-expression network constructed between BC and normal controls consisted of 182 nodes and 434 edges, and the two genes in each gene pair were differentially co-expressed genes. Centrality analysis of co-expression networks suggested that the top 5 hub genes with high degree included lectin, galactoside-binding, soluble, 4 (LGALS4), protein tyrosine phosphatase, receptor type N2 (PTPRN2), transmembrane protease, serine 11E (TMPRSS11E), tripartite motif containing 31 (TRIM31) and potassium voltage-gated channel subfamily D member 3 (KCND3). Pathway analysis revealed that the 329 DEGs were significantly enriched in 5 terms (cell cycle, DNA replication, oocyte meiosis, p53 signaling pathway and peroxisome proliferator-activated receptor signaling pathway). According to RT-qPCR and western blot analysis, 4/5 hub genes were significantly expressed, including LGALS4, PTPRN2, TMPRSS11E, TRIM31; however, KCND3 was not significantly expressed. In the present study, 5 hub genes were successfully identified (LGALS4, PTPRN2, TMPRSS11E, TRIM31 and KCND3) and 5 biological pathways that may be underlying biomarkers for early diagnosis and treatment associated with bladder cancer were revealed.

Tumor-Suppressor Gene NBPF1 Inhibits Invasion and PI3K/mTOR Signaling in Cervical Cancer Cells

The purpose of this study was to assess the effects of NBPF1 expression on cervical cancer cell invasion and apoptosis and to illustrate its potential mechanism. Human cervical cancer HeLa cells were transfected with the constructed siNBPF1 or pcDNA3.1-NBPF1 vectors. Effects of NBPF1 expression on cell invasion ability and cell apoptosis were analyzed using the Matrigel method and an Annexin V-FITC cell apoptosis kit, respectively. In addition, cell apoptosis-related proteins involved with the PI3K/mTOR signaling pathway were analyzed using Western blot. Remediation experiments were conducted to verify the effects of NBPF1 expression on cell invasion and apoptosis. Compared to the control, mRNA and protein expressions of NBPF1 were significantly decreased when cells were transfected with siNBPF1 (p < 0.05), which was contrary to the results of cells transfected with pcDNA3.1-NBPF1. Overexpression of NBPF1 significantly suppressed HeLa cell invasion but promoted cell apoptosis (p < 0.05). Overexpression of NBPF1 performed a significant inhibitory role on PI3K/mTOR signal pathway expression, while NBPF1 was silenced, showing contrary results. Our data suggested that NBPF1 overexpression may be a suppressor for cervical cancer via affecting cell invasion and apoptosis through regulating PI3K/mTOR signaling pathway. NBPF1 may be a potential therapeutic target for cervical cancer treatment.

Characterizing polymorphic inversions in human genomes by single-cell sequencing

Identifying genomic features that differ between individuals and cells can help uncover the functional variants that drive phenotypes and disease susceptibilities. For this, single-cell studies are paramount, as it becomes increasingly clear that the contribution of rare but functional cellular subpopulations is important for disease prognosis, management, and progression. Until now, studying these associations has been challenged by our inability to map structural rearrangements accurately and comprehensively. To overcome this, we coupled single-cell sequencing of DNA template strands (Strand-seq) with custom analysis software to rapidly discover, map, and genotype genomic rearrangements at high resolution. This allowed us to explore the distribution and frequency of inversions in a heterogeneous cell population, identify several polymorphic domains in complex regions of the genome, and locate rare alleles in the reference assembly. We then mapped the entire genomic complement of inversions within two unrelated individuals to characterize their distinct inversion profiles and built a nonredundant global reference of structural rearrangements in the human genome. The work described here provides a powerful new framework to study structural variation and genomic heterogeneity in single-cell samples, whether from individuals for population studies or tissue types for biomarker discovery.