Gene Summary

Gene:NAV1; neuron navigator 1
Summary:This gene belongs to the neuron navigator family and is expressed predominantly in the nervous system. The encoded protein contains coiled-coil domains and a conserved AAA domain characteristic for ATPases associated with a variety of cellular activities. This gene is similar to unc-53, a Caenorhabditis elegans gene involved in axon guidance. The exact function of this gene is not known, but it is thought to play a role in in neuronal development and regeneration. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Nov 2009]
Databases:OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:neuron navigator 1
Source:NCBIAccessed: 01 September, 2019


What does this gene/protein do?
Show (6)

Cancer Overview

Research Indicators

Publications Per Year (1994-2019)
Graph generated 01 September 2019 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

  • Cell Movement
  • Young Adult
  • Immunohistochemistry
  • Sodium Channel Blockers
  • Tetrodotoxin
  • Receptors, Progesterone
  • Muscle Proteins
  • Voltage-Gated Sodium Channel Blockers
  • Signal Transduction
  • NAV1.5 Voltage-Gated Sodium Channel
  • NAV1.1 Voltage-Gated Sodium Channel
  • Transcription Factors
  • Colorectal Cancer
  • Sodium Channels
  • Cancer Gene Expression Regulation
  • Cell Proliferation
  • Colonic Neoplasms
  • Voltage-Gated Sodium Channel beta-1 Subunit
  • Mutation
  • Transcription
  • Chromosome 1
  • Cervical Cancer
  • NAV1.7 Voltage-Gated Sodium Channel
  • Neoplasm Invasiveness
  • NAV1.6 Voltage-Gated Sodium Channel
  • Patch-Clamp Techniques
  • Neoplasm Metastasis
  • DNA Methylation
  • Messenger RNA
  • siRNA
  • Biomarkers, Tumor
  • Zinc Finger Protein GLI1
  • Prostate Cancer
  • Newborns
  • Twins
  • Tumor Suppressor Proteins
  • Nerve Tissue Proteins
  • Sodium-Hydrogen Exchangers
  • Breast Cancer
  • Western Blotting
Tag cloud generated 01 September, 2019 using data from PubMed, MeSH and CancerIndex

Specific Cancers (4)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: NAV1 (cancer-related)

Gumushan Aktas H, Akgun T
Naringenin inhibits prostate cancer metastasis by blocking voltage-gated sodium channels.
Biomed Pharmacother. 2018; 106:770-775 [PubMed] Related Publications
In this study, we investigated the potential effects of naringenin on the motility of MAT-LyLu cells, which overexpress voltage-gated sodium channels and whose metastatic behaviours are associated with these channels. We first determined the concentration of naringenin that did not show toxic effects or block cell growth. Then, the effects of naringenin on cell motility in the lateral and vertical directions were tested by wound healing assays and transwell invasion assays, respectively. Finally, to determine the suppressive effects of naringenin on cell movement in both directions, the expression of the SCN9A gene, which encodes Nav1.7 voltage-gated sodium channel, was determined by real-time quantitative polymerase chain reaction. The data revealed that high concentrations of naringenin (75 μM) inhibited cell proliferation, whereas low concentrations (5 and 10 μM) decreased the movement of MAT-LyLu cells. Moreover, 10 μM naringenin displayed inhibitory effects on cell movement by reducing the expression of the SCN9A gene at the mRNA level. In conclusion, naringenin was found to have direct or indirect blocking activity on voltage-gated sodium channels encoded by the SCN9A gene.

Liu J, Liu D, Liu JJ, et al.
Blocking the Nav1.5 channel using eicosapentaenoic acid reduces migration and proliferation of ovarian cancer cells.
Int J Oncol. 2018; 53(2):855-865 [PubMed] Related Publications
Activity of the voltage-gated Nav1.5 sodium channel has been reported to be involved in cell proliferation, cancer invasion and gene expression. In addition, eicosapentaenoic acid (EPA) has recently been suggested to inhibit ovarian cancer cell growth and suppress tumor metastasis. The present study aimed to explore the association between EPA, the Nav1.5 sodium channel and ovarian cancer cells. Using patch-clamp technique and RNA interference approaches, sodium currents were recorded in epithelial ovarian cancer cells, and it was confirmed that the Nav1.5 channel carried the sodium currents. Furthermore, EPA effectively inhibited sodium currents in a dose-dependent manner, shifted the steady-state inactivation curve of sodium currents to the hyperpolarizing direction and reduced sodium window currents. In addition, EPA induced a shift in the inactivation curve in a dose-dependent manner. Inhibition of the sodium channel, either by EPA or by Nav1.5 knockdown, attenuated ovarian cancer cell migration and proliferation. To the best of our knowledge, the present study is the first to conduct sodium current recording in ovarian cancer cells, and revealed that EPA may inhibit Nav1.5-mediated ovarian cancer cell migration and growth. These findings not only present a potential prognostic biomarker for ovarian cancer, but also provide a strategy towards the development of novel pharmacological treatments for patients with ovarian cancer.

Yapa KTDS, Deuis J, Peters AA, et al.
Assessment of the TRPM8 inhibitor AMTB in breast cancer cells and its identification as an inhibitor of voltage gated sodium channels.
Life Sci. 2018; 198:128-135 [PubMed] Related Publications
AIMS: To assess levels of the calcium permeable transient receptor potential cation channel, subfamily melastatin, member 8 (TRPM8) in breast cancer molecular subtypes and to assess the consequences of TRPM8 pharmacological inhibition with AMTB (an inhibitor of TRPM8) on breast cancer cell lines.
MATERIALS AND METHODS: Cell viability and migration of breast cancer cells was determined using MTS assays and wound healing assays, respectively. RNA-Seq analysis of breast tumours and qPCR in breast cancer cell lines were used to assess mRNA levels of ion channels. Membrane potential assays were employed to assess the effects of AMTB against specific voltage gated sodium channels (Na
KEY FINDINGS: TRPM8 levels were significantly higher in breast cancers of the basal molecular subtype. AMTB decreased viable cell number in MDA-MB-231 and SK-BR-3 breast cancer cell lines (30 and 100 μM), and also reduced the migration of MDA-MB-231 cells (30 μM). However, these effects were independent of TRPM8, as no TRPM8 mRNA was detected in MDA-MB-231 cells. AMTB was identified as an inhibitor of Na
SIGNIFICANCE: TRPM8 levels may be elevated in basal breast cancers, however, TRPM8 expression appears to be lost in many breast cancer cell lines. Some of the effects of AMTB attributed to TRPM8 may be due to effects on Na

Peng J, Ou Q, Wu X, et al.
Expression of voltage-gated sodium channel Nav1.5 in non-metastatic colon cancer and its associations with estrogen receptor (ER)-β expression and clinical outcomes.
Chin J Cancer. 2017; 36(1):89 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Voltage-gated sodium channel 1.5 (Nav1.5) potentially promotes the migratory and invasive behaviors of colon cancer cells. Hitherto, the prognostic significance of Nav1.5 expression remains undetermined. The present study aimed to explore the associations of Nav1.5 expression with clinical outcomes and estrogen receptor-β (ER-β) expression in non-metastatic colon cancer patients receiving radical resection.
METHODS: A total of 269 consecutive patients with pathologically confirmed stages I-III colon cancer who underwent radical resection were selected. Nav1.5 and ER-β expression was detected by using immunohistochemistry (IHC) on tissue microarray constructed from paraffin-embedded specimens. IHC score was determined according to the percentage and intensity of positively stained cells. Statistical analysis was performed with the X-tile method, k coefficient, Chi square test or Fisher's exact test, logistic regression, log-rank test, and Cox proportional hazards models.
RESULTS: We found that Nav1.5 was commonly expressed in tumor tissues with higher mean IHC score as compared with matched tumor-adjacent normal tissues (5.1 ± 3.5 vs. 3.5 ± 2.7, P < 0.001). The high expression of Nav1.5 in colon cancer tissues was associated with high preoperative carcinoembryonic antigen level [odds ratio (OR) = 2.980; 95% confidential interval (CI) 1.163-7.632; P = 0.023] and high ER-β expression (OR = 2.808; 95% CI 1.243-6.343; P = 0.013). Log-rank test results showed that high Nav1.5 expression contributed to a low 5-year disease-free survival (DFS) rate in colon cancer patients (77.2% vs. 92.1%, P = 0.048), especially in patients with high ER-β expression tumor (76.2% vs. 91.3%, P = 0.032). Analysis with Cox proportional hazards model demonstrated that high Nav1.5 expression [hazard ratio (HR) = 2.738; 95% CI 1.100-6.819; P = 0.030] and lymph node metastasis (HR = 2.633; 95% CI 1.632-4.248; P < 0.001) were prognostic factors for unfavorable DFS in colon cancer patients.
CONCLUSIONS: High expression of Nav1.5 was associated with high expression of ER-β and indicated unfavorable oncologic prognosis in patients with non-metastatic colon cancer.

Yamaci RF, Fraser SP, Battaloglu E, et al.
Neonatal Nav1.5 protein expression in normal adult human tissues and breast cancer.
Pathol Res Pract. 2017; 213(8):900-907 [PubMed] Related Publications
Expression of the neonatal splice variant of the voltage-gated sodium channel α-subunit (VGSC) subtype Nav1.5 (nNav1.5), encoded by the gene SCN5A, was shown earlier to be upregulated in human breast cancer (BCa), both in vitro and in vivo. Channel activity promoted BCa invasion of Matrigel

Wang S, He Z, Li D, et al.
Aberrant methylation of RUNX3 is present in Aflatoxin B
Toxicology. 2017; 385:1-9 [PubMed] Related Publications
Chronic exposure to aflatoxin B

Sereno M, Gutiérrez-Gutiérrez G, Rubio JM, et al.
Genetic polymorphisms of SCN9A are associated with oxaliplatin-induced neuropathy.
BMC Cancer. 2017; 17(1):63 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Oxaliplatin is a chemotherapy agent active against digestive tumors. Peripheral neuropathy is one of the most important dose-limiting toxicity of this drug. It occurs in around 60-80% of the patients, and 15% of them develop severe neuropathy. The pathophysiology of oxaliplatin neurotoxicity remains unclear. SCN9A is a gene codifying for a subtype sodium channel (type IX, subunit α) and mutations in this gene are involved in neuropathic perception. In this study we investigated whether SCN9A genetic variants were associated with risk of neurotoxicity in patients diagnosed of cancer on treatment with oxaliplatin.
METHODS: Blood samples from 94 patients diagnosed of digestive cancer that had received oxaliplatin in adjuvant or metastatic setting were obtained from three hospitals in Madrid. These patients were classified into two groups: "cases" developed oxaliplatin-induced grade 3-4 neuropathy (n = 48), and "controls" (n = 46) had no neuropathy or grade 1. The neuropathy was evaluated by an expert neurologist and included a clinical examination and classification according to validated neurological scales: National Cancer Institute Common Toxicity Criteria (NCI-CTC), Oxaliplatin-Specific Neurotoxicity Scale (OSNS) and Total Neuropathy score (TNS). Genotyping was performed for 3 SCN9A missense polymorphisms: rs6746030 (R1150W), rs74401238 (R1110Q) and rs41268673 (P610T), and associations between genotypes and neuropathy were evaluated.
RESULTS: We found that SCN9A rs6746030 was associated with protection for severe neuropathy (OR = 0.39, 95% CI = 0.16-0.96; p = 0.041). Multivariate analysis adjusting for diabetes provided similar results (p = 0.036). No significant differences in neuropathy risk were detected for rs74401238 and rs41268673.
CONCLUSION: SCN9A rs6746030 was associated with protection for severe oxaliplatin-induced peripheral neuropathy. The validation of this exploratory study is ongoing in an independent series.

Clendenen N, Cannon AD, Porter S, et al.
Whole-exome sequencing of a family with local anesthetic resistance.
Minerva Anestesiol. 2016; 82(10):1089-1097 [PubMed] Related Publications
BACKGROUND: Local anesthetics (LA) work by blocking sodium conductance through voltage-gated sodium channels. Complete local anesthetic resistance is infrequent, and the cause is unknown. Genetic variation in sodium channels is a potential mechanism for local anesthetic resistance. A patient with a history of inadequate loss of sensation following LA administration underwent an ultrasound-guided brachial plexus nerve block with a complete failure of the block. We hypothesized that LA resistance is due to a variant form of voltage-gated sodium channel.
METHODS: Whole-Exome Sequencing. The patient and her immediate family provided consent for exome sequencing, and they were screened with a questionnaire to identify family members with a history of LA resistance. Exome sequencing results for four individuals were referenced to the 1000 Genomes Project and the NHLBI ESP to identify variants associated with local anesthetic resistance present in less than 1% of the general population and located in functional regions of the genome.
RESULTS: Exome sequencing of the four family members identified one genetic variant in the voltage-gated sodium channel shared by the three individuals with LA resistance but not present in the unaffected family member. Specifically, we noted the A572D mutation in the SCN5A gene encoding for Nav1.5.
CONCLUSIONS: We identified a genetic variant that is associated with LA resistance in the gene encoding for Nav1.5. We also demonstrate that Nav1.5 is present in human peripheral nerves to support the plausibility that an abnormal form of the Nav1.5 protein could be responsible for the observed local anesthetic resistance.

Xia J, Huang N, Huang H, et al.
Voltage-gated sodium channel Nav 1.7 promotes gastric cancer progression through MACC1-mediated upregulation of NHE1.
Int J Cancer. 2016; 139(11):2553-69 [PubMed] Related Publications
Voltage-gated sodium channels (VGSCs), which are aberrantly expressed in several human cancers, affect cancer cell behavior; however, their role in gastric cancer (GC) and the link between these channels and tumorigenic signaling remain unclear. The aims of this study were to determine the clinicopathological significance and role of the VGSC Nav 1.7 in GC progression and to investigate the associated mechanisms. Here, we report that the SCN9A gene encoding Nav 1.7 was the most abundantly expressed VGSC subtype in GC tissue samples and two GC cell lines (BGC-823 and MKN-28 cells). SCN9A expression levels were also frequently found to be elevated in GC samples compared to nonmalignant tissues by real-time PCR. In the 319 GC specimens evaluated by immunohistochemistry, Nav 1.7 expression was correlated with prognosis, and transporter Na(+) /H(+) exchanger-1 (NHE1) and oncoprotein metastasis-associated in colon cancer-1 (MACC1) expression. Nav 1.7 suppression resulted in reduced voltage-gated sodium currents, decreased NHE1 expression, increased extracellular pH and decreased intracellular pH, and ultimately, reduced invasion and proliferation rates of GC cells and growth of GC xenografts in nude mice. Nav 1.7 inhibition led to reduced MACC1 expression, while MACC1 inhibition resulted in reduced NHE1 expression in vitro and in vivo. Mechanistically, the suppression of Nav 1.7 decreased NF-κB p65 nuclear translocation via p38 activation, thus reducing MACC1 expression. Downregulation of MACC1 decreased c-Jun phosphorylation and subsequently reduced NHE1 expression, whereas the addition of hepatocyte growth factor (HGF), a c-Met physiological ligand, reversed the effect. These results indicate that Nav 1.7 promotes GC progression through MACC1-mediated upregulation of NHE1. Therefore, Nav 1.7 is a potential prognostic marker and/or therapeutic target for GC.

Hernandez-Muñoz I, Figuerola E, Sanchez-Molina S, et al.
RING1B contributes to Ewing sarcoma development by repressing the NaV1.6 sodium channel and the NF-κB pathway, independently of the fusion oncoprotein.
Oncotarget. 2016; 7(29):46283-46300 [PubMed] Free Access to Full Article Related Publications
Ewing sarcoma (ES) is an aggressive tumor defined by EWSR1 gene fusions that behave as an oncogene. Here we demonstrate that RING1B is highly expressed in primary ES tumors, and its expression is independent of the fusion oncogene. RING1B-depleted ES cells display an expression profile enriched in genes functionally involved in hematological development but RING1B depletion does not induce cellular differentiation. In ES cells, RING1B directly binds the SCN8A sodium channel promoter and its depletion results in enhanced Nav1.6 expression and function. The signaling pathway most significantly modulated by RING1B is NF-κB. RING1B depletion results in enhanced p105/p50 expression, which sensitizes ES cells to apoptosis by FGFR/SHP2/STAT3 blockade. Reduced NaV1.6 function protects ES cells from apoptotic cell death by maintaining low NF-κB levels. Our findings identify RING1B as a trait of the cell-of-origin and provide a potential targetable vulnerability.

Aydar E, Stratton D, Fraser SP, et al.
Sigma-1 receptors modulate neonatal Na
Eur Biophys J. 2016; 45(7):671-683 [PubMed] Related Publications
The main aim of this study was to investigate a possible functional connection between sigma-1 receptors and voltage-gated sodium channels (VGSCs) in human breast cancer cells. The hypothesis was that sigma-1 drugs could alter the metastatic properties of breast cancer cells via the VGSC. Evidence was found for expression of sigma-1 receptor and neonatal Na

Lasorsa VA, Formicola D, Pignataro P, et al.
Exome and deep sequencing of clinically aggressive neuroblastoma reveal somatic mutations that affect key pathways involved in cancer progression.
Oncotarget. 2016; 7(16):21840-52 [PubMed] Free Access to Full Article Related Publications
The spectrum of somatic mutation of the most aggressive forms of neuroblastoma is not completely determined. We sought to identify potential cancer drivers in clinically aggressive neuroblastoma.Whole exome sequencing was conducted on 17 germline and tumor DNA samples from high-risk patients with adverse events within 36 months from diagnosis (HR-Event3) to identify somatic mutations and deep targeted sequencing of 134 genes selected from the initial screening in additional 48 germline and tumor pairs (62.5% HR-Event3 and high-risk patients), 17 HR-Event3 tumors and 17 human-derived neuroblastoma cell lines.We revealed 22 significantly mutated genes, many of which implicated in cancer progression. Fifteen genes (68.2%) were highly expressed in neuroblastoma supporting their involvement in the disease. CHD9, a cancer driver gene, was the most significantly altered (4.0% of cases) after ALK.Other genes (PTK2, NAV3, NAV1, FZD1 and ATRX), expressed in neuroblastoma and involved in cell invasion and migration were mutated at frequency ranged from 4% to 2%.Focal adhesion and regulation of actin cytoskeleton pathways, were frequently disrupted (14.1% of cases) thus suggesting potential novel therapeutic strategies to prevent disease progression.Notably BARD1, CHEK2 and AXIN2 were enriched in rare, potentially pathogenic, germline variants.In summary, whole exome and deep targeted sequencing identified novel cancer genes of clinically aggressive neuroblastoma. Our analyses show pathway-level implications of infrequently mutated genes in leading neuroblastoma progression.

Mohammed FH, Khajah MA, Yang M, et al.
Blockade of voltage-gated sodium channels inhibits invasion of endocrine-resistant breast cancer cells.
Int J Oncol. 2016; 48(1):73-83 [PubMed] Free Access to Full Article Related Publications
Voltage-gated Na+ channels (VGSCs) are membrane proteins which are normally expressed in excitable cells but have also been detected in cancer cells, where they are thought to be involved in malignancy progression. In this study we examined the ion current and expression profile of VGSC (Nav1.5) in estrogen receptor (ER)-positive (MCF-7) and silenced (pII) breast cancer cells and its possible influence on their proliferation, motility and invasion. VGSC currents were analysed by whole cell patch clamp recording. Nav1.5 expression and localization, in response to EGF stimulation, was examined by western blotting and immunofluorescence respectively. Cell invasion (under-agarose and Matrigel assays), motility (wound healing assay) and proliferation (MTT assay) were assessed in pII cells in response to VGSC blockers, phenytoin (PHT) and tetrodotoxin (TTX), or by siRNA knockdown of Nav1.5. The effect of PHT and TTX on modulating EGF-induced phosphorylation of Akt and ERK1/2 was determined by western blotting. Total matrix metalloproteinase (MMP) was determined using a fluorometric-based activity assay. The level of various human proteases was detected by using proteome profiler array kit. VGSC currents were detected in pII cells, but were absent in MCF-7. Nav1.5 showed cytoplasmic and perinuclear expression in both MCF-7 and pII cells, with enhanced expression upon EGF stimulation. Treatment of pII cells with PHT, TTX or siRNA significantly reduced invasion towards serum components and EGF, in part through reduction of P-ERK1/2 and proteases such as cathepsin E, kallikrein-10 and MMP-7, as well as total MMP activity. At high concentrations, PHT inhibited motility while TTX reduced cell proliferation. Pharmacological or genetic blockade of Nav1.5 may serve as a potential anti-metastatic therapy for breast cancer.

He YJ, Winham SJ, Hoskins JM, et al.
Carboplatin/taxane-induced gastrointestinal toxicity: a pharmacogenomics study on the SCOTROC1 trial.
Pharmacogenomics J. 2016; 16(3):243-8 [PubMed] Related Publications
Carboplatin/taxane combination is first-line therapy for ovarian cancer. However, patients can encounter treatment delays, impaired quality of life, even death because of chemotherapy-induced gastrointestinal (GI) toxicity. A candidate gene study was conducted to assess potential association of genetic variants with GI toxicity in 808 patients who received carboplatin/taxane in the Scottish Randomized Trial in Ovarian Cancer 1 (SCOTROC1). Patients were randomized into discovery and validation cohorts consisting of 404 patients each. Clinical covariates and genetic variants associated with grade III/IV GI toxicity in discovery cohort were evaluated in replication cohort. Chemotherapy-induced GI toxicity was significantly associated with seven single-nucleotide polymorphisms in the ATP7B, GSR, VEGFA and SCN10A genes. Patients with risk genotypes were at 1.53 to 18.01 higher odds to develop carboplatin/taxane-induced GI toxicity (P<0.01). Variants in the VEGF gene were marginally associated with survival time. Our data provide potential targets for modulation/inhibition of GI toxicity in ovarian cancer patients.

House CD, Wang BD, Ceniccola K, et al.
Voltage-gated Na+ Channel Activity Increases Colon Cancer Transcriptional Activity and Invasion Via Persistent MAPK Signaling.
Sci Rep. 2015; 5:11541 [PubMed] Free Access to Full Article Related Publications
Functional expression of voltage-gated Na(+) channels (VGSCs) has been demonstrated in multiple cancer cell types where channel activity induces invasive activity. The signaling mechanisms by which VGSCs promote oncogenesis remain poorly understood. We explored the signal transduction process critical to VGSC-mediated invasion on the basis of reports linking channel activity to gene expression changes in excitable cells. Coincidentally, many genes transcriptionally regulated by the SCN5A isoform in colon cancer have an over-representation of cis-acting sites for transcription factors phosphorylated by ERK1/2 MAPK. We hypothesized that VGSC activity promotes MAPK activation to induce transcriptional changes in invasion-related genes. Using pharmacological inhibitors/activators and siRNA-mediated gene knockdowns, we correlated channel activity with Rap1-dependent persistent MAPK activation in the SW620 human colon cancer cell line. We further demonstrated that VGSC activity induces downstream changes in invasion-related gene expression via a PKA/ERK/c-JUN/ELK-1/ETS-1 transcriptional pathway. This is the first study illustrating a molecular mechanism linking functional activity of VGSCs to transcriptional activation of invasion-related genes.

Igci YZ, Bozgeyik E, Borazan E, et al.
Expression profiling of SCN8A and NDUFC2 genes in colorectal carcinoma.
Exp Oncol. 2015; 37(1):77-80 [PubMed] Related Publications
AIM: The expression differences of SCN8A (which encodes type VIII alpha subunit of voltage gated sodium channel) and NDUFC2 (which encodes C2 subunit of Complex I enzyme in oxidative phosphorylation) genes were evaluated in paired colorectal cancer (CRC) tissues which was relied on our partial transcriptome analysis data in cancer cell lines.
MATERIALS AND METHODS: A total of 62 paired tissues of CRC patients (34 male, 28 female) were included in the study. The mRNA levels of SCN8A and NDUFC2 genes were determined by using real-time PCR (qRT-PCR and semiquantitative PCR).
RESULTS: SCN8A gene expression level was significantly lower in tumor tissues (p = 0.0128) and in the patients with the age below 45 years (p = 0.0049). There were also meaningful relationships between the gender, grade of CRC, tumor location, histopathological classification, and SCN8A expression. There was no NDUFC2 differential expression. However, the tumors taken from right colon had significantly lower NDUFC2 expression.
CONCLUSION: Although the voltage gated sodium channels (VGSCs) and Complex I (CI) were associated to a number of diseases including different types of cancers, the different subunits of CI and individual members of VGSCs seem to be cancer type-specific in varying proportions.

Xing D, Wang J, Ou S, et al.
Expression of neonatal Nav1.5 in human brain astrocytoma and its effect on proliferation, invasion and apoptosis of astrocytoma cells.
Oncol Rep. 2014; 31(6):2692-700 [PubMed] Related Publications
In the present study, we designed and conducted a series of assays to determine the expression of voltage-gated sodium channel (VGSC) neonatal isoform Nav1.5 (nNav1.5) in human brain astrocytoma and its effect on the proliferation, migration, invasion and apoptosis of astrocytoma U251 cells. The results showed that nNav1.5 mRNA and protein were expressed in both human brain astrocytoma and normal brain tissues, but their expression levels in astrocytoma were significantly higher (P<0.05). In astrocytomas, nNav1.5 mRNA and protein levels were also different (P<0.05) and were correlated with pathological grades. The immunofluorescence confocal microscopy observations demonstrated that nNav1.5 protein was expressed in the nucleus, cytoplasm and membrane of the astrocytoma cells. After transfection, the small interfering RNA (siRNA) targeted to nNav1.5 significantly reduced the expression levels of SCN5A/nNav1.5 mRNA and protein by 57.2% (P<0.05) and 66.6% (P<0.05), respectively. The MTT, wound healing, Matrigel invasion and flow cytometric assays confirmed that following siRNA downregulation of the expression of the SCN5A/nNav1.5 gene, the in vitro proliferation and in vitro invasiveness of the U251 cells were significantly reduced (P<0.05 for both comparisons), and the apoptosis rate was significantly increased (P<0.05). These results revealed that nNav1.5 expression in human brain astrocytoma was upregulated, and its expression was positively correlated with the degree of malignancy. Additionally, reduced nNav1.5 expression significantly suppressed the proliferation and invasiveness of astrocytoma cells, indicating a new target in the molecular diagnosis and therapy of astrocytoma.

Morrison CD, Liu P, Woloszynska-Read A, et al.
Whole-genome sequencing identifies genomic heterogeneity at a nucleotide and chromosomal level in bladder cancer.
Proc Natl Acad Sci U S A. 2014; 111(6):E672-81 [PubMed] Free Access to Full Article Related Publications
Using complete genome analysis, we sequenced five bladder tumors accrued from patients with muscle-invasive transitional cell carcinoma of the urinary bladder (TCC-UB) and identified a spectrum of genomic aberrations. In three tumors, complex genotype changes were noted. All three had tumor protein p53 mutations and a relatively large number of single-nucleotide variants (SNVs; average of 11.2 per megabase), structural variants (SVs; average of 46), or both. This group was best characterized by chromothripsis and the presence of subclonal populations of neoplastic cells or intratumoral mutational heterogeneity. Here, we provide evidence that the process of chromothripsis in TCC-UB is mediated by nonhomologous end-joining using kilobase, rather than megabase, fragments of DNA, which we refer to as "stitchers," to repair this process. We postulate that a potential unifying theme among tumors with the more complex genotype group is a defective replication-licensing complex. A second group (two bladder tumors) had no chromothripsis, and a simpler genotype, WT tumor protein p53, had relatively few SNVs (average of 5.9 per megabase) and only a single SV. There was no evidence of a subclonal population of neoplastic cells. In this group, we used a preclinical model of bladder carcinoma cell lines to study a unique SV (translocation and amplification) of the gene glutamate receptor ionotropic N-methyl D-aspertate as a potential new therapeutic target in bladder cancer.

Dulong C, Fang YJ, Gest C, et al.
The small GTPase RhoA regulates the expression and function of the sodium channel Nav1.5 in breast cancer cells.
Int J Oncol. 2014; 44(2):539-47 [PubMed] Related Publications
Voltage-gated Na+ channels (VGSCs) are highly expressed in several types of carcinomas including breast, prostate and lung cancers as well as in mesothelioma and cervical cancers. Although the VGSCs activity is considered crucial for the potentiation of cancer cell migration and invasion, the mechanisms responsible for their functional expression and regulation in cancer cells remain unclear. In the present study, the role of the small GTPase RhoA in the regulation of expression and function of the Nav1.5 channel in the breast cancer cell lines MDA-MB 231 and MCF-7 was investigated. RhoA silencing significantly reduced both Nav1.5 channel expression and sodium current indicating that RhoA exerts a stimulatory effect on the synthesis of an active form of Nav1.5 channel in cancer cells. The inhibition of Nav1.5 expression dramatically reduced both cell invasion and proliferation. In addition, a decrease of RhoA protein levels induced by Nav1.5 silencing was observed. Altogether, these findings revealed: i) the key role of the small GTPase RhoA in upregulation of Nav1.5 channel expression and tumor aggressiveness, and ii) the existence of a positive feedback of Nav1.5 channels on RhoA protein levels.

Bird EV, Christmas CR, Loescher AR, et al.
Correlation of Nav1.8 and Nav1.9 sodium channel expression with neuropathic pain in human subjects with lingual nerve neuromas.
Mol Pain. 2013; 9:52 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Voltage-gated sodium channels Nav1.8 and Nav1.9 are expressed preferentially in small diameter sensory neurons, and are thought to play a role in the generation of ectopic activity in neuronal cell bodies and/or their axons following peripheral nerve injury. The expression of Nav1.8 and Nav1.9 has been quantified in human lingual nerves that have been previously injured inadvertently during lower third molar removal, and any correlation between the expression of these ion channels and the presence or absence of dysaesthesia investigated.
RESULTS: Immunohistochemical processing and quantitative image analysis revealed that Nav1.8 and Nav1.9 were expressed in human lingual nerve neuromas from patients with or without symptoms of dysaesthesia. The level of Nav1.8 expression was significantly higher in patients reporting pain compared with no pain, and a significant positive correlation was observed between levels of Nav1.8 expression and VAS scores for the symptom of tingling. No significant differences were recorded in the level of expression of Nav1.9 between patients with or without pain.
CONCLUSIONS: These results demonstrate that Nav1.8 and Nav1.9 are present in human lingual nerve neuromas, with significant correlations between the level of expression of Nav1.8 and symptoms of pain. These data provide further evidence that changes in expression of Nav1.8 are important in the development and/or maintenance of nerve injury-induced pain, and suggest that Nav1.8 may be a potential therapeutic target.

Campbell TM, Main MJ, Fitzgerald EM
Functional expression of the voltage-gated Na⁺-channel Nav1.7 is necessary for EGF-mediated invasion in human non-small cell lung cancer cells.
J Cell Sci. 2013; 126(Pt 21):4939-49 [PubMed] Related Publications
Various ion channels are expressed in human cancers where they are intimately involved in proliferation, angiogenesis, invasion and metastasis. Expression of functional voltage-gated Na(+) channels (Nav) is implicated in the metastatic potential of breast, prostate, lung and colon cancer cells. However, the cellular mechanisms that regulate Nav expression in cancer remain largely unknown. Growth factors are attractive candidates; they not only play crucial roles in cancer progression but are also key regulators of ion channel expression and activity in non-cancerous cells. Here, we examine the role of epidermal growth factor receptor (EGFR) signalling and Nav in non-small cell lung carcinoma (NSCLC) cell lines. We show unequivocally, that functional expression of the α subunit Nav1.7 promotes invasion in H460 NSCLC cells. Inhibition of Nav1.7 activity (using tetrodotoxin) or expression (by using small interfering RNA), reduces H460 cell invasion by up to 50%. Crucially, non-invasive wild type A549 cells lack functional Nav, whereas exogenous overexpression of the Nav1.7 α subunit is sufficient to promote TTX-sensitive invasion of these cells. EGF/EGFR signalling enhances proliferation, migration and invasion of H460 cells but we find that, specifically, EGFR-mediated upregulation of Nav1.7 is necessary for invasive behaviour in these cells. Examination of Nav1.7 expression at mRNA, protein and functional levels further reveals that EGF/EGFR signalling via the ERK1/2 pathway controls transcriptional regulation of channel expression to promote cellular invasion. Immunohistochemistry of patient biopsies confirms the clinical relevance of Nav1.7 expression in NSCLC. Thus, Nav1.7 has significant potential as a new target for therapeutic intervention and/or as a diagnostic or prognostic marker in NSCLC.

Harris RA, Nagy-Szakal D, Kellermayer R
Human metastable epiallele candidates link to common disorders.
Epigenetics. 2013; 8(2):157-63 [PubMed] Free Access to Full Article Related Publications
Metastable epialleles (MEs) are mammalian genomic loci where epigenetic patterning occurs before gastrulation in a stochastic fashion leading to systematic interindividual variation within one species. Importantly, periconceptual nutritional influences may modulate the establishment of epigenetic changes, such as DNA methylation at MEs. Based on these characteristics, we exploited Infinium HumanMethylation450 BeadChip kits in a 2-tissue parallel screen on peripheral blood leukocyte and colonic mucosal DNA from 10 children without identifiable large intestinal disease. This approach led to the delineation of 1776 CpG sites meeting our criteria for MEs, which associated with 1013 genes. The list of ME candidates exhibited overlaps with recently identified human genes (including CYP2E1 and MGMT, where methylation has been associated with Parkinson disease and glioblastoma, respectively) in which perinatal DNA methylation levels where linked to maternal periconceptual nutrition. One hundred 18 (11.6%) of the ME candidates overlapped with genes where DNA methylation correlated (r > 0.871; p < 0.055) with expression in the colon mucosa of 5 independent control children. Genes involved in homophilic cell adhesion (including cadherin-associated genes) and developmental processes were significantly overrepresented in association with MEs. Additional filtering of gene expression-correlated MEs defined 35 genes, associated with 2 or more CpG sites within a 10 kb genomic region, fulfilling the ME criteria. DNA methylation changes at a number of these genes have been linked to various forms of human disease, including cancers, such as asthma and acute myeloid leukemia (ALOX12), gastric cancer (EBF3), breast cancer (NAV1), colon cancer and acute lymphoid leukemia (KCNK15), Wilms tumor (protocadherin gene cluster; PCDHAs) and colorectal cancer (TCERG1L), suggesting a potential etiologic role for MEs in tumorigenesis and underscoring the possible developmental origins of these malignancies. The presented compendium of ME candidates may accelerate our understanding of the epigenetic origins of common human disorders.

Altarescu G, Beeri R, Eldar-Geva T, et al.
PGD for germline mosaicism.
Reprod Biomed Online. 2012; 25(4):390-5 [PubMed] Related Publications
The aim of this study was to develop and perform a preimplantation genetic diagnosis (PGD) assay discriminating between wild-type and mutant alleles in two families with germline mosaicism. Family 1 had two children affected with severe myoclonic epilepsy (SCNA1A del exons 1-22). Family 2 had two children with tuberous sclerosis (TSC2 C1327T) and two healthy children. Neither mutation was detected in genomic DNA derived from the parents in either family. Informative microsatellite markers flanking SCNA1A and TSC2 along with the identified mutations were used to construct haplotypes. For tuberous sclerosis, single spermatozoa were analysed using a multiplex assay that included six informative markers and the TSC2 mutation. In family 1, deletion in the maternal allele was detected in the affected child. In family 2, both affected children and one healthy child shared the same paternal allele. To confirm mutant paternal transmission, single spermatozoa were analysed for the mutation along with six markers. Of 44 single spermatozoa, four showed the mutant T allele, allowing linkage between the mutation and the genetic markers. Both families delivered healthy children following IVF/PGD. In conclusion, germline mosaicism complicates allele assignment when constructing haplotypes for PGD. Sperm analysis is a useful tool for verifying allelic linkage.

Mohseny AB, Cai Y, Kuijjer M, et al.
The activities of Smad and Gli mediated signalling pathways in high-grade conventional osteosarcoma.
Eur J Cancer. 2012; 48(18):3429-38 [PubMed] Related Publications
High-grade conventional osteosarcoma is a malignant tumour predominantly affecting adolescents and, despite multimodal intensive therapy, lethal for one third of the patients. Although there is currently detailed knowledge of normal skeletal development, this has not been integrated into research on the genesis of osteosarcoma. Recently we showed that the canonical Wnt pathway is not active in osteosarcoma and that its reactivation is disadvantageous to osteosarcoma cells. Since Wnt is regulating normal skeletogenesis together with other pathways, here we report on the activities of the bone morphogenic protein (BMP), the transforming growth factor beta (TGFβ) and the hedgehog (Hh) pathways in osteosarcoma. Human osteosarcoma samples (n=210), benign bone tumours of osteoblastic lineage called osteoblastoma (n=25) and osteosarcoma cell lines (n=19) were examined. For pathway activity luciferase transcriptional reporter assays and gene and protein expression analyses were performed. Immunohistochemical analysis of phosphorylated Smad1 and Smad2, the intracellular effectors of BMP and TGFβ, respectively, showed nuclear expression of both proteins in 70% of the osteosarcoma samples at levels comparable to osteoblastoma. Interestingly cases with lower expression showed significantly worse disease free survival. This may imply that drugs restoring impaired signalling pathways in osteosarcoma might change the tumour's aggressive clinical course, however targeted pathway modulation in vitro did not affect cell proliferation.

Shiferaw K, Lobrinus AJ, Grabherr S, et al.
One case, 3 rare simultaneous findings: intramyocardial bronchogenic cyst, P.H558R variant of SCN5A gene, and granular cell tumor of the esophagus.
Am J Forensic Med Pathol. 2012; 33(4):335-8 [PubMed] Related Publications
We describe the sudden death of a 42-year-old white man. The decedent was a healthy young man with a short clinical history of chest pain, fatigue, dizziness, and pyrosis. Two weeks before his death, he underwent medical evaluation for the aforementioned symptoms. Electrocardiogram, chest x-ray, and serum troponin were all within normal limits. Gastroesophageal reflux disease was suspected, and the decedent was treated with omeprazole. Medicolegal autopsy disclosed an incidental intramyocardial bronchogenic cyst and p.H558R variant of the SCN5A gene. The cyst was located between the epicardium and myocardium of the posterior face of the left superior ventricular wall, adjacent to the base of the heart. An incidental granular cell tumor of the esophagus was also identified, which was likely unrelated to death.

Kim HG, Kim HT, Leach NT, et al.
Translocations disrupting PHF21A in the Potocki-Shaffer-syndrome region are associated with intellectual disability and craniofacial anomalies.
Am J Hum Genet. 2012; 91(1):56-72 [PubMed] Free Access to Full Article Related Publications
Potocki-Shaffer syndrome (PSS) is a contiguous gene disorder due to the interstitial deletion of band p11.2 of chromosome 11 and is characterized by multiple exostoses, parietal foramina, intellectual disability (ID), and craniofacial anomalies (CFAs). Despite the identification of individual genes responsible for multiple exostoses and parietal foramina in PSS, the identity of the gene(s) associated with the ID and CFA phenotypes has remained elusive. Through characterization of independent subjects with balanced translocations and supportive comparative deletion mapping of PSS subjects, we have uncovered evidence that the ID and CFA phenotypes are both caused by haploinsufficiency of a single gene, PHF21A, at 11p11.2. PHF21A encodes a plant homeodomain finger protein whose murine and zebrafish orthologs are both expressed in a manner consistent with a function in neurofacial and craniofacial development, and suppression of the latter led to both craniofacial abnormalities and neuronal apoptosis. Along with lysine-specific demethylase 1 (LSD1), PHF21A, also known as BHC80, is a component of the BRAF-histone deacetylase complex that represses target-gene transcription. In lymphoblastoid cell lines from two translocation subjects in whom PHF21A was directly disrupted by the respective breakpoints, we observed derepression of the neuronal gene SCN3A and reduced LSD1 occupancy at the SCN3A promoter, supporting a direct functional consequence of PHF21A haploinsufficiency on transcriptional regulation. Our finding that disruption of PHF21A by translocations in the PSS region is associated with ID adds to the growing list of ID-associated genes that emphasize the critical role of transcriptional regulation and chromatin remodeling in normal brain development and cognitive function.

Hernandez-Plata E, Ortiz CS, Marquina-Castillo B, et al.
Overexpression of NaV 1.6 channels is associated with the invasion capacity of human cervical cancer.
Int J Cancer. 2012; 130(9):2013-23 [PubMed] Related Publications
Functional activity of voltage-gated sodium channels (VGSC) has been associated to the invasion and metastasis behaviors of prostate, breast and some other types of cancer. We previously reported the functional expression of VGSC in primary cultures and biopsies derived from cervical cancer (CaC). Here, we investigate the relative expression levels of VGSC subunits and its possible role in CaC. Quantitative real-time PCR revealed that mRNA levels of Na(V) 1.6 α-subunit in CaC samples were ∼40-fold higher than in noncancerous cervical (NCC) biopsies. A Na(V) 1.7 α-subunit variant also showed increased mRNA levels in CaC (∼20-fold). All four Na(V) β subunits were also detected in CaC samples, being Na(V) β1 the most abundant. Proteins of Na(V) 1.6 and Na(V) 1.7 α-subunits were immunolocalized in both NCC and CaC biopsies and in CaC primary cultures as well; however, although in NCC sections proteins were mainly relegated to the plasma membrane, in CaC biopsies and primary cultures the respective signal was stronger and widely distributed in both cytoplasm and plasma membrane. Functional activity of Na(V) 1.6 channels in the plasma membrane of CaC cells was confirmed by whole-cell patch-clamp experiments using Cn2, a Na(V) 1.6-specific toxin, which blocked ∼30% of the total sodium current. Blocking of sodium channels VGSC with tetrodotoxin and Cn2 did not affect proliferation neither migration, but reduced by ∼20% the invasiveness of CaC primary culture cells in vitro assays. We conclude that Na(V) 1.6 is upregulated in CaC and could serve as a novel molecular marker for the metastatic behavior of this carcinoma.

Martín Del Valle F, Díaz Negrillo A, Ares Mateos G, et al.
Panayiotopoulos syndrome: probable genetic origin, but not in SCN1A.
Eur J Paediatr Neurol. 2011; 15(2):155-7 [PubMed] Related Publications
Panayiotopoulos syndrome is encompassed in the classification of the ILAE in idiopathic focal epilepsies. Mutations in the SCN1A gene have been associated with the development of this syndrome. We present two cases of Panayiotopoulos syndrome in two monozygotic twins, who underwent a molecular analysis of SCN1A, but no alteration was found. These cases suggest a genetic origin, and SCN1A appears to be associated with the outcome but not with the development of this syndrome.

Li L, Lee KM, Han W, et al.
Estrogen and progesterone receptor status affect genome-wide DNA methylation profile in breast cancer.
Hum Mol Genet. 2010; 19(21):4273-7 [PubMed] Related Publications
DNA methylation is the main epigenetic modification that occurs at the early stages of carcinogenesis. We performed a genome-wide DNA methylation profiling to evaluate whether the DNA methylation state is different in the estrogen receptor (ER) and progesterone receptor (PR) status of breast cancer. Twelve ER+/PR+ and 12 ER-/PR- breast cancer tissues were selected from the biorepository of the Seoul Breast Cancer Study for Infinium Methylation Assay. The difference of the DNA methylation state of 27 578 methylation sites in 14 000 genes between two groups was evaluated by Student's t-test. False discovery rate (FDR) was estimated to evaluate the probability of false positive associations. Of the 27 578 sites, 148 sites (0.54%) were significantly different between ER+/PR+ and ER-/PR- breast cancers (P < 0.001); 93 hypermethylated and 55 hypomethylated. Five genes, FAM124B (P = 7.26 × 10(-7)), MANEAL (P = 3.38 × 10(-7)), ST6GALNAC1 (P = 2.85 × 10(-6)), NAV1 (P = 5.94 × 10(-6)) and PER1 (P = 6.45 × 10(-6)) remained significant after correction for multiple tests (FDR < 0.05). In a subsequent replication study for five genes, four of the five genes were validated; FAM124B and ST6GALNAC1 were significantly hypermethylated, and NAV1 and PER1 were significantly hypomethylated in ER+/PR+ breast cancers (P < 0.05). In the first genome-wide DNA methylation profiling according to the receptor status of breast cancer, we found that ER/PR status affects the DNA methylation state of FAM124B, ST6GALNAC1, NAV1 and PER1 in breast cancer.

House CD, Vaske CJ, Schwartz AM, et al.
Voltage-gated Na+ channel SCN5A is a key regulator of a gene transcriptional network that controls colon cancer invasion.
Cancer Res. 2010; 70(17):6957-67 [PubMed] Free Access to Full Article Related Publications
Voltage-gated Na(+) channels (VGSC) have been implicated in the metastatic potential of human breast, prostate, and lung cancer cells. Specifically, the SCN5A gene encoding the VGSC isotype Na(v)1.5 has been defined as a key driver of human cancer cell invasion. In this study, we examined the expression and function of VGSCs in a panel of colon cancer cell lines by electrophysiologic recordings. Na(+) channel activity and invasive potential were inhibited pharmacologically by tetrodotoxin or genetically by small interfering RNAs (siRNA) specifically targeting SCN5A. Clinical relevance was established by immunohistochemistry of patient biopsies, with strong Na(v)1.5 protein staining found in colon cancer specimens but little to no staining in matched-paired normal colon tissues. We explored the mechanism of VGSC-mediated invasive potential on the basis of reported links between VGSC activity and gene expression in excitable cells. Probabilistic modeling of loss-of-function screens and microarray data established an unequivocal role of VGSC SCN5A as a high level regulator of a colon cancer invasion network, involving genes that encompass Wnt signaling, cell migration, ectoderm development, response to biotic stimulus, steroid metabolic process, and cell cycle control. siRNA-mediated knockdown of predicted downstream network components caused a loss of invasive behavior, demonstrating network connectivity and its function in driving colon cancer invasion.

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