Gene Summary

Gene:NEUROG1; neurogenin 1
Aliases: AKA, ngn1, Math4C, bHLHa6, NEUROD3
Databases:OMIM, HGNC, Ensembl, GeneCard, Gene
Source:NCBIAccessed: 01 September, 2019


What does this gene/protein do?
Show (18)

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.

  • Eye Cancer
  • Cancer Gene Expression Regulation
  • Chromosome 5
  • CpG Islands
  • DNA Sequence Analysis
  • Tissue Array Analysis
  • Basic Helix-Loop-Helix Transcription Factors
  • DNA Methylation
  • Gene Silencing
  • Proto-Oncogene Proteins p21(ras)
  • Promoter Regions
  • Nerve Tissue Proteins
  • Cohort Studies
  • Uveal Neoplasms
  • Neoplasm Proteins
  • Cancer DNA
  • Mutation
  • Colorectal Cancer
  • Long Interspersed Nucleotide Elements
  • Proto-Oncogene Proteins
  • Victoria
  • Biomarkers, Tumor
  • Tumor Suppressor Proteins
  • Genetic Predisposition
  • Retinoblastoma
  • Serpins
  • Polymerase Chain Reaction
  • Adenocarcinoma
  • BRAF
  • Epigenetics
  • Skin Cancer
  • Microsatellite Repeats
  • Immunohistochemistry
  • ras Proteins
  • beta Catenin
  • Microsatellite Instability
  • Loss of Heterozygosity
  • Staging
  • Phenotype
  • Risk Factors
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: NEUROG1 (cancer-related)

Singh V, Singh AP, Sharma I, et al.
Epigenetic deregulations of Wnt/β-catenin and transforming growth factor beta-Smad pathways in esophageal cancer: Outcome of DNA methylation.
J Cancer Res Ther. 2019 Jan-Mar; 15(1):192-203 [PubMed] Related Publications
Background: Promoter methylation of tumor suppressor genes (TSGs) is a well-reported portent in carcinogenesis; hence, it is worthy to investigate this in high-risk Northeast population of India. The study was designed to investigate methylation status of 94 TSGs in esophageal squamous cell carcinoma (ESCC). Further, the effect of OPCML promoter methylation on gene expression was analyzed by immunohistochemistry. Moreover, in silico protein-protein interactions were examined among 8 TSGs identified in the present study and 23 epigenetically regulated genes reported previously by our group in ESCC.
Materials and Methods: Methylation profiling was carried out by polymerase chain reaction array and OPCML protein expression was examined by tissue microarray-based immunohistochemistry.
Results: OPCML, NEUROG1, TERT, and WT1 genes were found hypermethylated and SCGB3A1, CDH1, THBS1, and VEGFA were hypomethylated in Grade 2 tumor. No significant change in OPCML expression was observed among control, Grade 1, and Grade 2 tumor. Conclusively, hypermethylation of the studied OPCML promoter in Grade 2 tumor produced no effect on expression. Unexpectedly, OPCML expression was downregulated in Grade 3 tumor in comparison to other groups signifying that downregulation of OPCML expression may lead to higher grade of tumor formation at the time of diagnosis of ESCC in patients. Significant interactions at protein level were found as VEGFA:PTK2, CTNNB1:CDH1, CTNNB1:VEGFA, CTNNB1:NEUROG1, CTNND2:CDH1, and CTNNB1:TERT. These interactions are pertinent to Wnt/β-catenin and TGF-β-Smad pathways.
Conclusions: Deranged OPCML expression may lead to high-grade ESCC as well as epigenetically regulated genes, that is, CDH1, CTNNB1, CTNND2, THBS1, PTK2, WT1, OPCML, TGFB1, and SMAD4 may alter the Wnt/β-catenin and TGF-β-Smad pathways in ESCC. Further study of these genes could be useful to understand the molecular pathology of ESCC with respect to epithelial-mesenchymal transition (EMT) mediated by Wnt/β-catenin and TGF-β signaling pathways.

Mäki-Nevala S, Valo S, Ristimäki A, et al.
DNA methylation changes and somatic mutations as tumorigenic events in Lynch syndrome-associated adenomas retaining mismatch repair protein expression.
EBioMedicine. 2019; 39:280-291 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: DNA mismatch repair (MMR) defects are a major factor in colorectal tumorigenesis in Lynch syndrome (LS) and 15% of sporadic cases. Some adenomas from carriers of inherited MMR gene mutations have intact MMR protein expression implying other mechanisms accelerating tumorigenesis. We determined roles of DNA methylation changes and somatic mutations in cancer-associated genes as tumorigenic events in LS-associated colorectal adenomas with intact MMR.
METHODS: We investigated 122 archival colorectal specimens of normal mucosae, adenomas and carcinomas from 57 LS patients. MMR-deficient (MMR-D, n = 49) and MMR-proficient (MMR-P, n = 18) adenomas were of particular interest and were interrogated by methylation-specific multiplex ligation-dependent probe amplification and Ion Torrent sequencing.
FINDINGS: Promoter methylation of CpG island methylator phenotype (CIMP)-associated marker genes and selected colorectal cancer (CRC)-associated tumor suppressor genes (TSGs) increased and LINE-1 methylation decreased from normal mucosa to MMR-P adenomas to MMR-D adenomas. Methylation differences were statistically significant when either adenoma group was compared with normal mucosa, but not between MMR-P and MMR-D adenomas. Significantly increased methylation was found in multiple CIMP marker genes (IGF2, NEUROG1, CRABP1, and CDKN2A) and TSGs (SFRP1 and SFRP2) in MMR-P adenomas already. Furthermore, certain CRC-associated somatic mutations, such as KRAS, were prevalent in MMR-P adenomas.
INTERPRETATION: We conclude that DNA methylation changes and somatic mutations of cancer-associated genes might serve as an alternative pathway accelerating LS-associated tumorigenesis in the presence of proficient MMR. FUND: Jane and Aatos Erkko Foundation, Academy of Finland, Cancer Foundation Finland, Sigrid Juselius Foundation, and HiLIFE.

Cha Y, Kim SY, Yeo HY, et al.
Association of CHFR Promoter Methylation with Treatment Outcomes of Irinotecan-Based Chemotherapy in Metastatic Colorectal Cancer.
Neoplasia. 2019; 21(1):146-155 [PubMed] Free Access to Full Article Related Publications
Aberrant promoter methylation plays a vital role in colorectal carcinogenesis. However, its role in treatment responses is unclear, especially for metastatic disease. Here, we investigated the association between promoter methylation and treatment outcomes of irinotecan-based chemotherapy in 102 patients with metastatic colorectal cancer. Promoter methylation was examined by methylation-specific polymerase chain reaction for three loci (CHFR, WRN, and SULF2) associated with chemotherapy response and five CpG island methylator phenotype (CIMP)-specific markers (CACNA1G, IGF2, NEUROG1, RUNX3, and SOCS1). Association between CHFR methylation and in vitro sensitivity to irinotecan was also evaluated. Promoter methylation of CHFR, WRN, and SULF2 was identified in 16 (15.7%), 24 (23.5%), and 33 (32.4%) patients, respectively. CIMP status was positive in 22 (21.6%) patients. CHFR methylation was associated with a significantly longer time to progression (TTP) (median: 8.77 vs. 4.43 months, P = .019), with trends favoring higher overall survival (OS) (median: 22.83 vs. 20.17 months, P = .300) and response rates (31.3% vs. 17.4%, P = .300). For patients with unmethylated CHFR, TTP (median: 5.60 vs. 3.53, P = .020) and OS (median: 20.57 vs. 9.23, P = .006) were significantly different according to CIMP status. Colorectal cancer cell lines with CHFR methylation demonstrated increased sensitivity to irinotecan. Both CHFR overexpression and combination with 5-aza-2'-deoxycytidine reversed irinotecan sensitivity in CHFR-methylated cell lines, whereas CHFR knockdown in unmethylated cells restored sensitivity to irinotecan. These data suggest that CHFR methylation may be associated with favorable treatment outcomes of irinotecan-based chemotherapy in patients with metastatic colorectal cancer.

French CA
NUT Carcinoma: Clinicopathologic features, pathogenesis, and treatment.
Pathol Int. 2018; 68(11):583-595 [PubMed] Related Publications
NUT carcinoma (NC) is a rare, aggressive subtype of squamous cell carcinoma defined by rearrangement of the NUTM1 (aka NUT) gene. NC is driven by NUT-fusion oncoproteins resulting from chromosomal translocation, most commonly BRD4-NUT. This is a nearly uniformly lethal cancer affecting patients of all ages, but predominantly teens and young adults. The cell of origin is unknown, but NC most commonly arises within the thorax and head and neck. NC typically consists of sheets of monomorphic primitive round cells that can exhibit focal abrupt squamous differentiation. Diagnosis of NC is easy, and can be established by positive NUT nuclear immunohistochemical staining. Though characterization of the NUTM1-fusion gene is desirable by molecular analysis, it is not required for the diagnosis. The increasingly widespread availability of the NUT diagnostic test is leading to increasing diagnoses of this vastly underdiagnosed disease. The NUT midline carcinoma registry ( serves as a central repository that has provided the main source of clinical and outcomes data for NC. Currently there is no effective therapy for NC, however small molecules directly targeting the BRD4 portion of BRD4-NUT, termed BET bromodomain inhibitors, have shown activity.

Yu M, Heinzerling TJ, Grady WM
DNA Methylation Analysis Using Droplet Digital PCR.
Methods Mol Biol. 2018; 1768:363-383 [PubMed] Related Publications
Droplet digital (ddPCR) is a recent advance in PCR technology that enables the precise detection and absolute quantification of nucleic acid target sequences and that has a range of applications for both research and clinical diagnostic studies. Here, we discuss the parameters important in the design and performance of ddPCR for the detection and quantification of methylated DNA. We provide explicit instructions for conducting methylation specific ddPCR (aka MethyLight ddPCR). We also present an example that demonstrates the sensitivity and precision of the method for detecting methylated DNA in the promoter region of mir342/EVL, a potential DNA methylation biomarker for colon cancer risk. Common technical problems and troubleshooting for conducting successful MethyLight ddPCR assays are also discussed.

Schaefer IM, Dal Cin P, Landry LM, et al.
CIC-NUTM1 fusion: A case which expands the spectrum of NUT-rearranged epithelioid malignancies.
Genes Chromosomes Cancer. 2018; 57(9):446-451 [PubMed] Related Publications
NUT carcinoma (NC) shows very aggressive clinical behavior, occurs predominantly in the thorax and head and neck region of children and adults, and is defined by the presence of NUT (aka NUTM1) rearrangement, mostly BRD4-NUTM1 fusion resulting from t(15;19)(q13; p13.1). So-called "NUT variants" harbor alternate fusions between NUTM1 and BRD3, NSD3, ZNF532, or unknown partners. Rare cases of pediatric tumors with CIC-NUTM1 fusion were recently reported in somatic soft tissue, brain, and kidney. However, such cases have not been identified in adult patients and the presence of a fusion between CIC, characteristic of CIC-rearranged sarcoma, and NUTM1-a defining feature of NC-poses a diagnostic challenge. We herein report a case of malignant epithelioid neoplasm with myoepithelial features harboring CIC-NUTM1 fusion arising in soft tissue of the head in a 60-year-old man. Immunohistochemistry revealed strong expression of NUT, but only weak ETV4 staining and negativity for keratins, EMA, p40, CD99, and WT1. SMARCB1 expression was retained. Fluorescence in situ hybridization and targeted next-generation sequencing identified a CIC-NUTM1 fusion resulting from t(15;19)(q14;q13.2). In light of morphologic features that overlap with those of NC from typical anatomical sites we have seen previously, the tumor was best classified as falling within the NC spectrum rather than CIC-associated sarcoma. This case highlights the emerging diagnostic challenges generated by newly detected gene fusions of unknown clinical and biologic significance. Careful integration of cytogenetic, molecular, and immunohistochemical findings with morphologic appearances in the diagnostic workup of undifferentiated neoplasms is essential.

Agaimy A, Fonseca I, Martins C, et al.
NUT Carcinoma of the Salivary Glands: Clinicopathologic and Molecular Analysis of 3 Cases and a Survey of NUT Expression in Salivary Gland Carcinomas.
Am J Surg Pathol. 2018; 42(7):877-884 [PubMed] Free Access to Full Article Related Publications
NUT carcinoma (NC) represents a rare subset of highly aggressive poorly differentiated carcinomas characterized by rearrangement of the NUT (aka NUTM1, nuclear protein in testis) gene, most commonly fused to BRD4. Originally described as a mediastinal/thymic malignancy, NC has been reported at a variety of anatomic regions including the upper and lower aerodigestive tract. To date, only 7 NC cases of probable salivary gland origin have been reported. We herein describe 3 new cases (all affecting the parotid gland) in 2 women (39- and 55-y old) and 1 man (35-y old). Histologic examination showed poorly differentiated neoplasms composed of poorly cohesive small-sized to medium-sized cells with variable squamoid cell component that was focal and abrupt. Immunohistochemistry showed uniform expression of p63 and distinctive punctate expression of the NUT antigen in the tumor cell nuclei. Review of the reported salivary gland NC cases (total, 10) showed a male:female ratio of 1.5:1 and an age range of 12 to 55 years (median, 29 y). Site of the primary tumor was the parotid (7), sublingual (2), and submandibular (1) glands. All presented as rapidly growing masses treated by surgery followed by adjuvant radiotherapy/chemotherapy. Initial nodal status was positive in 8/10. At last follow-up (1 to 24 mo; median, 5 mo), 7/10 patients died of disease at a median of 5.5 months (1 to 24 mo) and only 2 were disease free at 7 and 14 months. Of 9 cases with genetic data, the fusion partner was BRD4 (n=7), non-BRD4/3 (n=1), or undetermined (n=1). None of 306 carcinomas spanning the spectrum of salivary carcinoma types screened by NUT immunohistochemistry was positive. This is the first small series on salivary NC highlighting the importance to include this rare disease in the differential diagnosis of poorly differentiated salivary gland carcinomas and in cases of presumable poorly differentiated carcinoma of unknown origin.

Prachayakul V, Kanchanapermpoon J, Thuwajit C, et al.
DNA Methylation Markers Improve the Sensitivity of Endoscopic Retrograde Cholangiopancreatography-Based Brushing Cytology in Extrahepatic Cholangiocarcinoma.
Technol Cancer Res Treat. 2017; 16(6):1252-1258 [PubMed] Free Access to Full Article Related Publications
Endoscopic retrograde cholangiopancreatography with brushed cytology is still the standard method for the diagnosis of extrahepatic cholangiocarcinoma in obstructive jaundice; however, the diagnostic yield is limited. To improve the diagnostic sensitivity, DNA methylation analysis is an attractive candidate, since this may constitute a stable marker in brushed specimens. Therefore, this study aims to evaluate the importance of such epigenetic markers in brushed biliary cells from patients with obstructive jaundice for the diagnosis of extrahepatic cholangiocarcinoma. The cells examined were those that were left over from brushed cytology done during routine endoscopic retrograde cholangiopancreatography of patients with extrahepatic cholangiocarcinoma. The methylation states of HOXA1, RASSF1A, P16, and NEUROG1 genes in extrahepatic cholangiocarcinoma were measured by quantitative methylation-specific polymerase chain reaction and compared between brushed biliary cells and normal gall bladder epithelial cells. The results showed that the sensitivity of the methylation index measurements of HOXA1 and NEUROG1 genes from brushed samples was markedly superior to that of standard cytology. In conclusion, measurement of the DNA methylation status of HOXA1 and NEUROG1 genes in leftover brushed biliary cells might serve as a useful supplement in the detection of malignant biliary obstruction by increasing the sensitivity of diagnosis by routine cytology.

Matsuno R, Gifford AJ, Fang J, et al.
Rare MYC-amplified Neuroblastoma With Large Cell Histology.
Pediatr Dev Pathol. 2018 Sep-Oct; 21(5):461-466 [PubMed] Related Publications
Background Although MYCN (aka N-myc) amplification is reported in ∼20% of neuroblastomas, MYC (aka C-myc) amplification appears to be a rare event in this disease. As of today, only 2 MYC-amplified neuroblastomas have been briefly mentioned in the literature. Methods We studied here the clinicopathological features of 3 MYC-amplified neuroblastomas. Results All 3 patients (2 females and 1 male) had stage 4 disease. One female is currently alive and well 52 months after the diagnosis, while the other female and male patients died of disease 24 and 20 months after the diagnosis, respectively. Further analysis on 2 tumors revealed unfavorable histology with MYC protein overexpression but with neither MYCN amplification nor MYCN protein overexpression. Both of these tumors exhibited "large cell neuroblastoma" histology with enlarged, uniquely open nuclei and nucleolar hypertrophy, along with "aberrant" desmin expression. Conclusions MYC-amplified neuroblastomas are extremely rare and seem to present with distinct clinicopathological features.

Hühns M, Krohn S, Murua Escobar H, Prall F
Genomic heterogeneity in primary colorectal carcinomas and their metastases: born bad or brought up a villain?
Hum Pathol. 2018; 74:54-63 [PubMed] Related Publications
Progression of solid cancers, colorectal carcinomas among them, from their primaries to metastatic lesions traditionally is thought to proceed by a stepwise acquisition of and selection for genomic aberrations. To test if patterns of genomic aberrations would be consistent with this model, we studied 10 colorectal carcinoma primary-metastasis pairs, 9 with 1 liver metastasis each and 1 with 2 metastases. Next-generation targeted sequencing (50-gene panel) with samples obtained from different regions of the primaries and their metastases demonstrated 1-11 gene mutations per lesion. But only in 2 tumors were there seen mutations in all samples from the metastasis and not any of the primaries (BRAF

Youngren-Ortiz SR, Chougule MB
The Daniel K. Inouye College of Pharmacy Scripts: Targeted Nanocarrier Based Systems for the Treatment of Lung Cancer.
Hawaii J Med Public Health. 2017; 76(11):318-325 [PubMed] Free Access to Full Article Related Publications
In Hawai'i, lung cancer is among the top cancers diagnosed and a leading cause of death. Despite current understanding and modern surgery, radiology, and chemotherapy techniques, the survival of those suffering from lung cancer remains low. Current anticancer drugs have poor tumor tissue selectivity and toxicity issues that contribute to their overall low efficacy, detrimental effects to normal tissues, and drug resistance. A potential way of mitigating cancer is through RNA interference (RNAi) by the delivery of small interfering RNA (siRNA) to target select proteins or genes involved in cancer progression, known as oncoproteins or oncogenes, respectively. However, the clinical utility of delivering unformulated siRNA has been hindered due to poor cell penetration, nonspecific effects, rapid degradation, and short half-life. As an alternate for conventional chemotherapy, nanoparticles (AKA nanocarriers) may be designed to localize within the tumor environment and increase targeted cell internalization, thus reducing systemic adverse effects and increasing efficacy. Nanoparticles play important roles in drug delivery and have been widely studied for cancer therapy and diagnostics, termed collectively as theranostics. Nanoparticles composed of natural and artificial polymers, proteins, lipids, metals, and carbon-based materials have been developed for the delivery of siRNA. Cancer targeting has been improved by nanoparticle surface modification or conjugation with biomolecules that are attracted to or stimulate therapeutic agent release within cancer tissues or cells. In this mini-review article, we present recent progress in nanocarrier-mediated siRNA delivery systems that include lipid, polymer, metallic and carbon-based nanoparticles for lung cancer therapy.

Yindom LM, Mendy M, Bodimeade C, et al.
KIR content genotypes associate with carriage of hepatitis B surface antigen, e antigen and HBV viral load in Gambians.
PLoS One. 2017; 12(11):e0188307 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Hepatocellular carcinoma (HCC) causes over 800,000 deaths worldwide annually, mainly in low income countries, and incidence is rising rapidly in the developed world with the spread of hepatitis B (HBV) and C (HCV) viruses. Natural Killer (NK) cells protect against viral infections and tumours by killing abnormal cells recognised by Killer-cell Immunoglobulin-like Receptors (KIR). Thus genes and haplotypes encoding these receptors may be important in determining both outcome of initial hepatitis infection and subsequent chronic liver disease and tumour formation. HBV is highly prevalent in The Gambia and the commonest cause of liver disease. The Gambia Liver Cancer Study was a matched case-control study conducted between September 1997 and January 2001 where cases with liver disease were identified in three tertiary referral hospitals and matched with out-patient controls with no clinical evidence of liver disease.
METHODS: We typed 15 KIR genes using the polymerase chain reaction with sequence specific primers (PCR-SSP) in 279 adult Gambians, 136 with liver disease (HCC or Cirrhosis) and 143 matched controls. We investigated effects of KIR genotypes and haplotypes on HBV infection and associations with cirrhosis and HCC.
RESULTS: Homozygosity for KIR group A gene-content haplotype was associated with HBsAg carriage (OR 3.7, 95% CI 1.4-10.0) whilst telomeric A genotype (t-AA) was associated with reduced risk of e antigenaemia (OR 0.2, 95% CI 0.0-0.6) and lower viral loads (mean log viral load 5.2 vs. 6.9, pc = 0.022). One novel telomeric B genotype (t-ABx2) containing KIR3DS1 (which is rare in West Africa) was also linked to e antigenaemia (OR 8.8, 95% CI 1.3-60.5). There were no associations with cirrhosis or HCC.
CONCLUSION: Certain KIR profiles may promote clearance of hepatitis B surface antigen whilst others predispose to e antigen carriage and high viral load. Larger studies are necessary to quantify the effects of individual KIR genes, haplotypes and KIR/HLA combinations on long-term viral carriage and risk of liver cancer. KIR status could potentially inform antiviral therapy and identify those at increased risk of complications for enhanced surveillance.

Groisberg R, Roszik J, Conley A, et al.
The Role of Next-Generation Sequencing in Sarcomas: Evolution From Light Microscope to Molecular Microscope.
Curr Oncol Rep. 2017; 19(12):78 [PubMed] Related Publications
PURPOSE OF REVIEW: Sarcomas are rare, heterogeneous group of soft tissue and bone tumors. Precise diagnosis of specific subtypes is challenging using conventional methods. Herein, we review the role of next-generation sequencing (NGS) technology that is used for rapid sequencing of DNA and RNA.
RECENT FINDINGS: Recent sarcoma specific studies recommend that molecular genetic testing should be added at diagnosis for appropriate clinical management in addition to diagnosis by expert pathologists. NGS has already been used to identify potentially actionable mutations, copy number alterations, and gene fusions. Rationally, choosing a drug based on an individual patient profile aka: "precision oncology" has been so far limited to few case reports in sarcomas. As we improve our ability to deliver personalized medicine using all modalities including conventional therapy, more patients may eventually benefit. As the cost and capacity of NGS outpace Moore's law, so does the probability of success.

Choi JP, Yang X, Foley M, et al.
Induction and Micro-CT Imaging of Cerebral Cavernous Malformations in Mouse Model.
J Vis Exp. 2017; (127) [PubMed] Article available free on PMC after 04/09/2019 Related Publications
Mutations in the CCM1 (aka KRIT1), CCM2, or CCM3 (aka PDCD10) gene cause cerebral cavernous malformation (CCM) in humans. Mouse models of CCM disease have been established by tamoxifen induced deletion of Ccm genes in postnatal animals. These mouse models provide invaluable tools to investigate molecular mechanism and therapeutic approaches for CCM disease. An accurate and quantitative method to assess lesion burden and progression is essential to harness the full value of these animal models. Here, we demonstrate the induction of CCM disease in a mouse model and the use of the contrast enhanced X-ray micro computed tomography (micro-CT) method to measure CCM lesion burden in mouse brains. At postnatal day 1 (P1), we used 4-hydroxytamoxifen (4HT) to activate Cre recombinase activity from the Cdh5-CreErt2 transgene to cleave the floxed allele of Ccm2. CCM lesions in mouse brains were analyzed at P8. For micro-CT, iodine based Lugol's solution was used to enhance contrast in brain tissue. We have optimized the scan parameters and utilized a voxel dimension of 9.5 µm, which lead to a minimum feature size of approximately 25 µm. This resolution is sufficient to measure CCM lesion volume and number globally and accurately, and provide high-quality 3-D mapping of CCM lesions in mouse brains. This method enhances the value of the established mouse models to study the molecular basis and potential therapies for CCM and other cerebrovascular diseases.

Frey AB
The Inhibitory Signaling Receptor Protocadherin-18 Regulates Tumor-Infiltrating CD8
Cancer Immunol Res. 2017; 5(10):920-928 [PubMed] Related Publications
Cancers are infiltrated with antitumor CD8

Henriksen SD, Madsen PH, Larsen AC, et al.
Promoter hypermethylation in plasma-derived cell-free DNA as a prognostic marker for pancreatic adenocarcinoma staging.
Int J Cancer. 2017; 141(12):2489-2497 [PubMed] Related Publications
Correct staging of pancreatic cancer is paramount, as treatment is stage specific. However, minimally invasive tools to facilitate staging are lacking. DNA promoter hypermethylation is a hallmark of cancer. The aim of this study is to evaluate promoter hypermethylation in cell-free DNA as a prognostic marker for stage classification of pancreatic adenocarcinoma. Consecutive patients with pancreatic adenocarcinoma were prospectively included. Plasma samples were obtained before diagnostic work-up and treatment. Patients were staged according to the TNM classification. Methylation-specific PCR of 28 genes was performed. Prognostic prediction models for staging of pancreatic adenocarcinoma were developed by multivariable logistic regression analysis using stepwise backwards elimination. Ninety-five patients with pancreatic adenocarcinoma were included. The mean number of hypermethylated genes was identical for stage I, II and III disease (7.09 (95% CI; 5.51-8.66), 7.00 (95% CI; 5.93-8.07) and 6.77 (95% CI; 5.08-8.46)), respectively, and highly significantly different from stage IV disease (10.24 (95% CI; 8.88-11.60)). The prediction model (SEPT9v2, SST, ALX4, CDKN2B, HIC1, MLH1, NEUROG1, and BNC1) enabled the differentiation of stage IV from stage I-III disease (AUC of 0.87 (cut point 0.55; sensitivity 74%, specificity 87%)). Model (MLH1, SEPT9v2, BNC1, ALX4, CDKN2B, NEUROG1, WNT5A, and TFPI2) enabled the differentiation of stage I-II from stage III-IV disease (AUC of 0.82 (cut point 0.66; sensitivity 73%, specificity 80%)). Cell-free DNA promoter hypermethylation has the potential to be blood-based prognostic markers for pancreatic adenocarcinoma, as panels of hypermethylated genes enables the differentiation according to cancer stage. However, further validation is required.

Wang XQ, Aka JA, Li T, et al.
Inhibition of 17beta-hydroxysteroid dehydrogenase type 7 modulates breast cancer protein profile and enhances apoptosis by down-regulating GRP78.
J Steroid Biochem Mol Biol. 2017; 172:188-197 [PubMed] Related Publications
17beta-hydroxysteroid dehydrogenase type 7 (17β-HSD7) promotes breast cancer cell growth via dual-catalytic activity by modulating estradiol and DHT. Here, we clarified the expression pattern of 17β-HSD7 in postmenopausal luminal A type breast cancer with The Cancer Genome Atlas (TCGA) cohort. The impact of 17β-HSD7 inhibition on the proteome of MCF-7 cells was investigated and on cell apoptosis was revealed. MCF-7 cells were treated with an efficient inhibitor of 17β-HSD7 (INH7) or with vehicle, and a differential proteomics study was performed using two-dimensional (2D) gel electrophoresis followed by mass spectrometry and ingenuity pathway analysis (IPA). Cell apoptosis was analyzed by flow cytometry, followed by reverse transcription quantitative real-time PCR (RT-qPCR) and Western blot to investigate the expression of apoptosis-related genes. Our data showed 17β-HSD7 is amplified in primary and progressive breast cancer, inhibition of 17β-HSD7 in MCF-7 cells modulated 104 proteins primarily involved in cell death/survival, cell growth and DNA processing. The expression of 78kDa glucose-regulated protein (GRP78) and anti-apoptosis factor Bcl-2 were significantly suppressed via 17β-HSD7 inhibition with INH7, consequently induced MCF-7 cell apoptosis. However, INH7 treatment of T47D, another widely used epithelial ER+ breast cancer cell line, led to an up-regulation of GRP78 expression, resulting in a limited increase in apoptosis. These results suggest cell-specific effects of INH7 in the breast cancer, which is interesting for further study. An combinatory effect on apoptosis by INH7 and Letrozole (aromatase inhibitor) was further demonstrated in MCF-7. Down-regulation of GRP78 via 17β-HSD7 inhibition enhances cell apoptosis in response to Letrozole. This study highlights GRP78 as a key regulator related to 17β-HSD7 inhibition and effect. Taken together, results from the present study suggest a hypothesis that inhibition of 17β-HSD7 would be a complementary strategy to Letrozole by suppression of GRP78 in ER+ breast cancer. However, from a research perspective, further studies have to be carried out with more breast cancer cell lines as well as in vivo model to assess the efficacy of inhibitor combination.

Xu D, Aka JA, Wang R, Lin SX
17beta-hydroxysteroid dehydrogenase type 5 is negatively correlated to apoptosis inhibitor GRP78 and tumor-secreted protein PGK1, and modulates breast cancer cell viability and proliferation.
J Steroid Biochem Mol Biol. 2017; 171:270-280 [PubMed] Related Publications
17beta-hydroxysteroid dehydrogenase type 5 (17β-HSD5) is an important enzyme associated with sex steroid metabolism in hormone-dependent cancer. However, reports on its expression and its prognostic value in breast cancer are inconsistent. Here, we demonstrate the impact of 17β-HSD5 expression modulation on the proteome of estrogen receptor-positive (ER+) breast cancer cells. RNA interference technique (siRNA) was used to knock down 17β-HSD5 gene expression in the ER+ breast cancer cell line MCF-7 and the proteome of the 17β-HSD5-knockdown cells was compared to that of MCF-7 cells using two-dimensional (2-D) gel electrophoresis followed by mass spectrometry analysis. Ingenuity pathway analysis (IPA) was additionally used to assess functional enrichment analyses of the proteomic dataset, including protein network and canonical pathways. Our proteomic analysis revealed only four differentially expressed protein spots (fold change > 2, p<0.05) between the two cell lines. The four spots were up-regulated in 17β-HSD5-knockdown MCF-7 cells, and comprised 21 proteins involved in two networks and in functions that include apoptosis inhibition, regulation of cell growth and differentiation, signal transduction and tumor metastasis. Among the proteins are nucleoside diphosphate kinase A (NME1), 78kDa glucose-regulated protein (GRP78) and phosphoglycerate kinase 1 (PGK1). We also showed that expression of 17β-HSD5 and that of the apoptosis inhibitor GRP78 are strongly but negatively correlated. Consistent with their opposite regulation, GRP78 knockdown decreased MCF-7 cell viability whereas 17β-HSD5 knockdown or inhibition increased cell viability and proliferation. Besides, IPA analysis revealed that ubiquitination pathway is significantly affected by 17β-HSD5 knockdown. Furthermore, IPA predicted the proto-oncogene c-Myc as an upstream regulator linked to the tumor-secreted protein PGK1. The latter is over-expressed in invasive ductal breast carcinoma as compared with normal breast tissue and its expression increased following 17β-HSD5 knockdown. Our present results indicate a 17β-HSD5 role in down-regulating breast cancer development. We thus propose that 17β-HSD5 may not be a potent target for breast cancer treatment but its low expression could represent a poor prognosis factor.

Sexton-Oates A, Dodgshun A, Hovestadt V, et al.
Methylation profiling of paediatric pilocytic astrocytoma reveals variants specifically associated with tumour location and predictive of recurrence.
Mol Oncol. 2018; 12(8):1219-1232 [PubMed] Article available free on PMC after 04/09/2019 Related Publications
Childhood pilocytic astrocytomas (PA) are low-grade tumours with an excellent prognosis. However, a minority, particularly those in surgically inaccessible locations, have poorer long-term outcome. At present, it is unclear whether anatomical location in isolation, or in combination with underlying biological variation, determines clinical behaviour. Here, we have tested the utility of DNA methylation profiling to inform tumour biology and to predict behaviour in paediatric PA. Genome-wide DNA methylation profiles were generated for 117 paediatric PAs. Using a combination of analyses, we identified DNA methylation variants specific to tumour location and predictive of behaviour. Receiver-operating characteristic analysis was used to test the predictive utility of clinical and/or DNA methylation features to classify tumour behaviour at diagnosis. Unsupervised analysis distinguished three methylation clusters associated with tumour location (cortical, midline and infratentorial). Differential methylation of 5404 sites identified enrichment of genes involved in 'embryonic nervous system development'. Specific hypermethylation of NEUROG1 and NR2E1 was identified as a feature of cortical tumours. A highly accurate method to classify tumours according to behaviour, which combined three clinical features (age, location and extent of resection) and methylation level at a single site, was identified. Our findings show location-specific epigenetic profiles for PAs, potentially reflecting their cell type of origin. This may account for differences in clinical behaviour according to location independent of histopathology. We also defined an accurate method to predict tumour behaviour at diagnosis. This warrants further testing in similar patient cohorts.

Luo Z, Li Y, Zuo M, et al.
Effect of NR5A2 inhibition on pancreatic cancer stem cell (CSC) properties and epithelial-mesenchymal transition (EMT) markers.
Mol Carcinog. 2017; 56(5):1438-1448 [PubMed] Article available free on PMC after 04/09/2019 Related Publications
NR5A2 (aka LRH-1) has been identified as a pancreatic cancer susceptibility gene with missing biological link. This study aims to demonstrate expression and potential role of NR5A2 in pancreatic cancer. NR5A2 expression was quantified in resected pancreatic ductal adenocarcinomas and the normal adjacent tissues of 134 patients by immunohistochemistry. The intensity and extent of NR5A2 staining was quantified and analyzed in association with overall survival (OS). The impact of NR5A2 knockdown on pancreatic cancer stem cell (CSC) properties and epithelial-mesenchymal transition (EMT) markers was examined in cancer cells using RT-PCR and Western Blot. NR5A2 was overexpressed in pancreatic tumors, the IHC-staining H score (mean ± SE) was 96.4 ± 8.3 in normal versus 137.9 ± 8.2 in tumor tissues (P < 0.0001). Patients with a higher NR5A2 expression had a median survival time 18.4 months compared to 23.7 months for those with low IHC H scores (P = 0.019). The hazard ratio of death (95% confidence interval) was 1.60 (1.07-2.41) after adjusting for disease stage and tumor grade (P = 0.023). NR5A2 was highly expressed in pancreatic cancer sphere forming cells. NR5A2-inhibition by siRNA was associated with reduced sphere formation and decreased levels of CSCs markers NANOG, OCT4, LIN28B, and NOTCH1. NR5A2 knockdown also resulted in reduced expression of FGB, MMP2, MMP3, MMMP9, SNAIL, and TWIST, increased expression of epithelial markers E-cadherin and β-catenin, and a lower expression of mesenchymal marker Vimentin. Taken together, our findings suggest that NR5A2 could play a role in CSC stemness and EMT in pancreatic cancer, which may contribute to the worse clinical outcome.

Bhatt S, Stender JD, Joshi S, et al.
OCT-4: a novel estrogen receptor-α collaborator that promotes tamoxifen resistance in breast cancer cells.
Oncogene. 2016; 35(44):5722-5734 [PubMed] Related Publications
Tamoxifen has shown great success in the treatment of breast cancer; however, long-term treatment can lead to acquired tamoxifen (TOT) resistance and relapse. TOT classically antagonizes estradiol (E2) -dependent breast cancer cell growth, but exerts partial agonist/antagonist behavior on gene expression. Although both E2 and TOT treatment of breast cancer cells results in recruitment of the estrogen receptor (ER) to common and distinct genomic sites, the mechanisms and proteins underlying TOT preferential recruitment of the ER remains poorly defined. To this end, we performed in silico motif-enrichment analyses within the ER-binding peaks in response to E2 or TOT, to identify factors that would specifically recruit ER to genomic binding sites in the presence of TOT as compared to E2. Intriguingly, we found Nkx3-1 and Oct-transcription factor homodimer motifs to be enriched in TOT preferential binding sites and confirmed the critical role of Oct-3/4 (aka Oct-4) in directing ER recruitment to TOT preferential genomic binding sites, by chromatin immunoprecipitation (ChIP) analyses. Further investigation revealed Oct-4 expression to be basally repressed by Nkx3-1 in MCF-7 cells and TOT treatment appeared to elevate Nkx3-1 degradation through a p38MAPK-dependent phosphorylation of the E3 ligase, Skp2 at serine-64 residue, as observed by quantitative mass-spectrometry analyses. Consistently, Oct-4 upon induction by phospho-Ser64-Skp2-mediated proteasomal degradation of Nkx3-1, participated in ER transcriptional complexes along with p38MAPK and Skp2 in a tamoxifen-dependent manner leading to TOT-dependent gene activation and cell proliferation of the TOT-resistant MCF-7-tam

Dunkel Y, Diao K, Aznar N, et al.
Prognostic impact of total and tyrosine phosphorylated GIV/Girdin in breast cancers.
FASEB J. 2016; 30(11):3702-3713 [PubMed] Article available free on PMC after 04/09/2019 Related Publications
Gα-interacting vesicle-associated protein (GIV, aka Girdin) is a guanine exchange factor (GEF) for the trimeric G protein Gαi and a bona fide metastasis-related gene that serves as a platform for amplification of tyrosine-based signals via G-protein intermediates. Here we present the first exploratory biomarker study conducted on a cohort of 187 patients with breast cancer to evaluate the prognostic role of total GIV (tGIV) and tyrosine phosphorylated GIV (pYGIV) across the various molecular subtypes. A Kaplan-Meier analysis of recurrence-free survival showed that the presence of tGIV, either cytoplasmic or nuclear, carried poor prognosis, but that nuclear tGIV had a greater prognostic impact (P = 0.007 in early and P = 0.0048 in late clinical stages). Activated pYGIV in the cytoplasm had the greatest prognostic impact in late clinical stages (P = 0.006). Furthermore, we found that the prognostic impacts of cytoplasmic pYGIV and nuclear tGIV were additive (hazard ratio 19.0548; P = 0.0002). Surprisingly, this additive effect of nuclear tGIV/cytoplasmic pYGIV was observed in human epidermal growth factor receptor 2-positive tumors (hazard ratio 16.918; P = 0.0005) but not in triple-negative breast cancers. In triple-negative breast cancers, tGIV and cytoplasmic pYGIV had no prognostic impact; however, membrane-association of pYGIV carried a poor prognosis (P = 0.026). Both tGIV and pYGIV showed no correlation with clinical stage, tumor size, pathologic type, lymph node involvement, and BRCA1/2 status. We conclude that immunocytochemical detection of pYGIV and tGIV can serve as an effective prognosticator. On the basis of the differential prognostic impact of tGIV/pYGIV within each molecular subtype, we propose a diagnostic algorithm. Further studies on larger cohorts are essential to rigorously assess the effectiveness and robustness of this algorithm in prognosticating outcome among patients with breast cancer.-Dunkel, Y., Diao, K., Aznar, N., Swanson, L., Liu, L., Zhu, W., Mi, X.-Y., Ghosh, P. Prognostic impact of total and tyrosine phosphorylated GIV/Girdin in breast cancers.

Ginn KF, Fangman B, Terai K, et al.
RalA is overactivated in medulloblastoma.
J Neurooncol. 2016; 130(1):99-110 [PubMed] Related Publications
Medulloblastoma (MDB) represents a major form of malignant brain tumors in the pediatric population. A vast spectrum of research on MDB has advanced our understanding of the underlying mechanism, however, a significant need still exists to develop novel therapeutics on the basis of gaining new knowledge about the characteristics of cell signaling networks involved. The Ras signaling pathway, one of the most important proto-oncogenic pathways involved in human cancers, has been shown to be involved in the development of neurological malignancies. We have studied an important effector down-stream of Ras, namely RalA (Ras-Like), for the first time and revealed overactivation of RalA in MDB. Affinity precipitation analysis of active RalA (RalA-GTP) in eight MDB cell lines (DAOY, RES256, RES262, UW228-1, UW426, UW473, D283 and D425) revealed that the majority contained elevated levels of active RalA (RalA-GTP) as compared with fetal cerebellar tissue as a normal control. Additionally, total RalA levels were shown to be elevated in 20 MDB patient samples as compared to normal brain tissue. The overall expression of RalA, however, was comparable in cancerous and normal samples. Other important effectors of RalA pathway including RalA binding protein-1 (RalBP1) and protein phosphatase A (PP2A) down-stream of Ral and Aurora kinase A (AKA) as an upstream RalA activator were also investigated in MDB. Considering the lack of specific inhibitors for RalA, we used gene specific silencing in order to inhibit RalA expression. Using a lentivirus expressing anti-RalA shRNA we successfully inhibited RalA expression in MDB and observed a significant reduction in proliferation and invasiveness. Similar results were observed using inhibitors of AKA and geranyl-geranyl transferase (non-specific inhibitors of RalA signaling) in terms of loss of in vivo tumorigenicity in heterotopic nude mouse model. Finally, once tested in cells expressing CD133 (a marker for MDB cancer stem cells), higher levels of RalA activation was observed. These data not only bring RalA to light as an important contributor to the malignant phenotype of MDB but introduces this pathway as a novel target in the treatment of this malignancy.

Aka JA, Calvo EL, Lin SX
Estradiol-independent modulation of breast cancer transcript profile by 17beta-hydroxysteroid dehydrogenase type 1.
Mol Cell Endocrinol. 2017; 439:175-186 [PubMed] Related Publications
17beta-hydroxysteroid dehydrogenase type 1 (17β-HSD1) is a steroidal enzyme which, in breast cancer cells, mainly synthesizes 17-beta-estradiol (E2), an estrogenic hormone that stimulates breast cancer cell growth. We previously showed that the enzyme increased breast cancer cell proliferation via a dual effect on E2 and 5α-dihydrotestosterone (DHT) levels and impacted gene expression and protein profile of breast cancer cells cultured in E2-contained medium. Here, we used RNA interference technique combined with microarray analyses to investigate the effect of 17β-HSD1 expression on breast cancer cell transcript profile in steroid-deprived condition. Our data revealed that knockdown of 17β-HSD1 gene, HSD17B1, modulates the transcript profile of the hormone-dependent breast cancer cell line T47D, with 105 genes regulated 1.5 fold or higher (p < 0.05) in estradiol-independent manner. Using Ingenuity Pathway Analysis (IPA), we additionally assessed functional enrichment analyses, including biological functions and canonical pathways, and found that, in concordance with the role of 17β-HSD1 in cancer cell growth, most regulated genes are cancer-related genes. Genes that primarily involved in the cell cycle progression, such as the cyclin A2 gene, CCNA2, are generally down-regulated whereas genes involved in apoptosis and cell death, including the pro-apoptotic gene XAF1, IFIH1 and FGF12, are on the contrary up-regulated by 17β-HSD1 knockdown, and 21% of the modulated genes belong to this latter functional category. This indicates that 17β-HSD1 may be involved in oncogenesis by favoring anti-apoptosis pathway in breast cancer cells and correborates with its previously shown role in increasing breast cancer cell proliferation. The gene regulation occurring in steroid-deprived conditions showed that 17β-HSD1 can modulate endogenous gene expression in steroid-independent manners. Besides, we tested the ability of estrogen to induce or repress endogenous genes of T47D by microarray analysis. Expression of a total of 130 genes were found to increase or decrease 1.5-fold or higher (p < 0.05) in response to E2 treatment (1 nM for 48 h), revealing a list of potential new estrogen-responsive genes and providing useful information for further studies of estrogen-dependent breast cancer mechanisms. In conclusion, in breast cancer cells, in addition to its implication in the E2-dependent gene transcription, the present study demonstrates that 17β-HSD1 also modulates gene expression via mechanisms independent of steroid actions. Those mechanisms that may include the ligand-independent gene transcription of estrogen receptor alpha (ERα), whose expression is positively correlated with that of the enzyme, and that may implicate 17β-HSD1 in anti-apoptosis pathways, have been discussed.

Rasmussen SL, Krarup HB, Sunesen KG, et al.
Hypermethylated DNA as a biomarker for colorectal cancer: a systematic review.
Colorectal Dis. 2016; 18(6):549-61 [PubMed] Related Publications
AIM: Improved methods for early detection of colorectal cancer (CRC) are essential for increasing survival. Hypermethylated DNA in blood or stool has been proposed as a biomarker for CRC. Biochemical methods have improved in recent years, and several hypermethylated genes that are sensitive and specific for CRC have been proposed. Articles describing the use of hypermethylated promoter regions in blood or stool as biomarkers for CRC were systematically reviewed.
METHOD: A systematic literature search was performed using the Medline, Web of Science and Embase databases. Studies were included if they analysed hypermethylated genes from stool or blood samples in correlation with CRC. Studies in languages other than English and those based on animal models or cell lines were excluded.
RESULTS: The literature search yielded 74 articles, including 43 addressing blood samples and 31 addressing stool samples. In blood samples, hypermethylated ALX4, FBN2, HLTF, P16, TMEFF1 and VIM were associated with poor prognosis, hypermethylated APC, NEUROG1, RASSF1A, RASSF2A, SDC2, SEPT9, TAC1 and THBD were detected in early stage CRC and hypermethylated P16 and TFPI2 were associated with CRC recurrence. In stool samples, hypermethylated BMP3, PHACTR3, SFRP2, SPG20, TFPI2 and TMEFF2 were associated with early stage CRC.
CONCLUSION: Hypermethylation of the promoters of specific genes measured in blood or stool samples could be used as a CRC biomarker and provide prognostic information. The majority of studies, however, include only a few patients with poorly defined control groups. Further studies are therefore needed before hypermethylated DNA can be widely applied as a clinical biomarker for CRC detection and prognosis.

Yu H, Hageman Blair R
Pac Symp Biocomput. 2016; 21:69-80 [PubMed] Related Publications
Understanding community structure in networks has received considerable attention in recent years. Detecting and leveraging community structure holds promise for understanding and potentially intervening with the spread of influence. Network features of this type have important implications in a number of research areas, including, marketing, social networks, and biology. However, an overwhelming majority of traditional approaches to community detection cannot readily incorporate information of node attributes. Integrating structural and attribute information is a major challenge. We propose a exible iterative method; inverse regularized Markov Clustering (irMCL), to network clustering via the manipulation of the transition probability matrix (aka stochastic flow) corresponding to a graph. Similar to traditional Markov Clustering, irMCL iterates between "expand" and "inflate" operations, which aim to strengthen the intra-cluster flow, while weakening the inter-cluster flow. Attribute information is directly incorporated into the iterative method through a sigmoid (logistic function) that naturally dampens attribute influence that is contradictory to the stochastic flow through the network. We demonstrate advantages and the exibility of our approach using simulations and real data. We highlight an application that integrates breast cancer gene expression data set and a functional network defined via KEGG pathways reveal significant modules for survival.

Shearer RF, Iconomou M, Watts CK, Saunders DN
Functional Roles of the E3 Ubiquitin Ligase UBR5 in Cancer.
Mol Cancer Res. 2015; 13(12):1523-32 [PubMed] Related Publications
The Ubiquitin-Proteasome System (UPS) is an important regulator of cell signaling and proteostasis, which are essential to a variety of cellular processes. The UPS is disrupted in many diseases including cancer, and targeting the UPS for cancer therapy is gaining wide interest. E3 ubiquitin ligases occupy a key position in the hierarchical UPS enzymatic cascade, largely responsible for determining substrate specificity and ubiquitin (Ub) chain topology. The E3 ligase UBR5 (aka EDD1) is emerging as a key regulator of the UPS in cancer and development. UBR5 expression is deregulated in many cancer types and UBR5 is frequently mutated in mantle cell lymphoma. UBR5 is highly conserved in metazoans, has unique structural features, and has been implicated in regulation of DNA damage response, metabolism, transcription, and apoptosis. Hence, UBR5 is a key regulator of cell signaling relevant to broad areas of cancer biology. However, the mechanism by which UBR5 may contribute to tumor initiation and progression remains poorly defined. This review synthesizes emerging insights from genetics, biochemistry, and cell biology to inform our understanding of UBR5 in cancer. These molecular insights indicate a role for UBR5 in integrating/coordinating various cellular signaling pathways. Finally, we discuss outstanding questions in UBR5 biology and highlight the need to systematically characterize substrates, and address limitations in current animal models, to better define the role of UBR5 in cancer.

Zynda ER, Matveev V, Makhanov M, et al.
Protein kinase A type II-α regulatory subunit regulates the response of prostate cancer cells to taxane treatment.
Cell Cycle. 2014; 13(20):3292-301 [PubMed] Article available free on PMC after 04/09/2019 Related Publications
In the last decade taxane-based therapy has emerged as a standard of care for hormone-refractory prostate cancer. Nevertheless, a significant fraction of tumors show no appreciable response to the treatment, while the others develop resistance and recur. Despite years of intense research, the mechanisms of taxane resistance in prostate cancer and other malignancies are poorly understood and remain a topic of intense investigation. We have used improved mutagenesis via random insertion of a strong promoter to search for events, which enable survival of prostate cancer cells after Taxol exposure. High-throughput mapping of the integration sites pointed to the PRKAR2A gene, which codes for a type II-α regulatory subunit of protein kinase A, as a candidate modulator of drug response. Both full-length and N-terminally truncated forms of the PRKAR2A gene product markedly increased survival of prostate cancer cells lines treated with Taxol and Taxotere. Suppression of protein kinase A enzymatic activity is the likely mechanism of action of the overexpressed proteins. Accordingly, protein kinase A inhibitor PKI (6-22) amide reduced toxicity of Taxol to prostate cancer cells. Our findings support the role of protein kinase A and its constituent proteins in cell response to chemotherapy.

Bianco S, Jangal M, Garneau D, Gévry N
LRH-1 controls proliferation in breast tumor cells by regulating CDKN1A gene expression.
Oncogene. 2015; 34(34):4509-18 [PubMed] Related Publications
Liver receptor homolog-1 (LRH-1, NR5A2) is an orphan nuclear receptor that has an essential role in cancer progression, notably in breast cancer. Although its role in promoting cancer cell proliferation and migration is well documented, the molecular basis is not completely established. Here, we report that LRH-1 inhibition affects two- and three-dimensional cell proliferation of different types of breast cancer cells, including estrogen receptor α (ERα)-positive and triple-negative cells. This phenotype is accompanied by the upregulation of the cyclin-dependent kinase inhibitor CDKN1A (aka p21(CIP1/WAF1)) in a p53-independent manner. Chromatin immunoprecipitation analysis shows that LRH-1 cooperates with FOXA1 and binds directly to CDKN1A promoter and a distal regulatory region found at -62 kb from its transcriptional start sites, allowing repression of CDKN1A transcription. LRH-1 or FOXA1 depletion induces CDKN1A upregulation by removing histone deacetylase 2 from the promoter and distal regulatory elements and permitting histone acetylation in these regions. Analysis of breast cancer samples reveals that a high LRH-1 level is inversely correlated with CDKN1A expression in breast cancer patients and is associated with poor prognosis. This study reveals a novel mechanism of control of cell proliferation by LRH-1 regulating CDKN1A transcription in breast cancer cells, independent of ERα and p53 status. Targeting LRH-1 may provide an attractive prospect for treatment of tumors that are resistant to hormonal and targeted therapy.

Hu Y, Petit SA, Ficarro SB, et al.
PARP1-driven poly-ADP-ribosylation regulates BRCA1 function in homologous recombination-mediated DNA repair.
Cancer Discov. 2014; 4(12):1430-47 [PubMed] Article available free on PMC after 04/09/2019 Related Publications
UNLABELLED: BRCA1 promotes homologous recombination-mediated DNA repair (HRR). However, HRR must be tightly regulated to prevent illegitimate recombination. We previously found that BRCA1 HRR function is regulated by the RAP80 complex, but the mechanism was unclear. We have now observed that PARP1 interacts with and poly-ADP-ribosylates (aka PARsylates) BRCA1. PARsylation is directed at the BRCA1 DNA binding domain and downmodulates its function. Moreover, RAP80 contains a poly-ADP-ribose-interacting domain that binds PARsylated BRCA1 and helps to maintain the stability of PARP1-BRCA1-RAP80 complexes. BRCA1 PARsylation is a key step in BRCA1 HRR control. When BRCA1 PARsylation is defective, it gives rise to excessive HRR and manifestations of genome instability. BRCA1 PARsylation and/or RAP80 expression is defective in a subset of sporadic breast cancer cell lines and patient-derived tumor xenograft models. These observations are consistent with the possibility that such defects, when chronic, contribute to tumor development in BRCA1+/+ individuals.
SIGNIFICANCE: We propose a model that describes how BRCA1 functions to both support and restrict HRR. BRCA1 PARsylation is a key event in this process, failure of which triggers hyper-recombination and chromosome instability. Thus, hyperfunctioning BRCA1 can elicit genomic abnormalities similar to those observed in the absence of certain BRCA1 functions.

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