RAD23B

Gene Summary

Gene:RAD23B; RAD23 homolog B, nucleotide excision repair protein
Aliases: P58, HR23B, HHR23B
Location:9q31.2
Summary:The protein encoded by this gene is one of two human homologs of Saccharomyces cerevisiae Rad23, a protein involved in the nucleotide excision repair (NER). This protein was found to be a component of the protein complex that specifically complements the NER defect of xeroderma pigmentosum group C (XP-c) cell extracts in vitro. This protein was also shown to interact with, and elevate the nucleotide excision activity of 3-methyladenine-DNA glycosylase (MPG), which suggested a role in DNA damage recognition in base excision repair. This protein contains an N-terminal ubiquitin-like domain, which was reported to interact with 26S proteasome, and thus this protein may be involved in the ubiquitin mediated proteolytic pathway in cells. Alternative splicing results in multiple transcript variants encoding distinct isoforms. [provided by RefSeq, Sep 2011]
Databases:VEGA, OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:UV excision repair protein RAD23 homolog B
Source:NCBIAccessed: 15 March, 2017

Ontology:

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

Cancer Overview

Research Indicators

Publications Per Year (1992-2017)
Graph generated 15 March 2017 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.

  • Risk Factors
  • Young Adult
  • Up-Regulation
  • DNA-Binding Proteins
  • Survival Rate
  • Prostate Cancer
  • Endonucleases
  • Chromosome 9
  • HeLa Cells
  • DNA Helicases
  • Case-Control Studies
  • Cancer DNA
  • Bladder Cancer
  • DNA Repair Enzymes
  • Breast Cancer
  • Odds Ratio
  • Smoking
  • Genome-Wide Association Study
  • Pyrimidines
  • Genetic Predisposition
  • European Continental Ancestry Group
  • Nuclear Proteins
  • Xenograft Models
  • African Americans
  • Genetic Variation
  • DNA Repair
  • Tumor Suppressor Proteins
  • Saccharomyces cerevisiae Proteins
  • Transcription Factors
  • Lung Cancer
  • Liver Cancer
  • Apoptosis
  • Xeroderma Pigmentosum
  • Logistic Models
  • Single Nucleotide Polymorphism
  • Oligonucleotide Array Sequence Analysis
  • Cancer Gene Expression Regulation
  • United Kingdom
  • Xeroderma Pigmentosum Group D Protein
  • Genotype
  • MicroRNAs
  • Binding Sites
Tag cloud generated 15 March, 2017 using data from PubMed, MeSH and CancerIndex

Specific Cancers (5)

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: RAD23B (cancer-related)

Yokoi M, Hanaoka F
Two mammalian homologs of yeast Rad23, HR23A and HR23B, as multifunctional proteins.
Gene. 2017; 597:1-9 [PubMed] Related Publications
Mammalian cells express two homologs of yeast Rad23, the so-called homolog of Rad23 (HR23) proteins. The HR23 proteins were identified more than two decades ago as factors involved in initiation of global genome nucleotide excision repair (GG-NER) along with their interacting partner, xeroderma pigmentosum group C (XPC) protein. Because the HR23 genes encode proteins harboring ubiquitin-like (UBL) domains at their N-termini and two ubiquitin-associated (UBA) domains in their central- and C-terminal regions, the link between HR23 proteins and proteolytic degradation has been widely explored by several methods, including yeast two-hybrid screening and co-affinity purification. To date, various HR23 protein partners have been identified, and these proteins are involved not only in DNA repair, but also in ubiquitin-dependent protein degradation, transcriptional regulation, and cell cycle control. In addition, establishment of mouse strains lacking the HR23 genes and RNA silencing of these genes in human cells demonstrated their significance in animal development and cell growth. Through these studies, the functional differences between the two HR23 proteins have been gradually revealed. Furthermore, recent comprehensive proteomic analyses will help to elucidate the functional protein-protein networks involving the HR23 proteins.

Saunders EJ, Dadaev T, Leongamornlert DA, et al.
Gene and pathway level analyses of germline DNA-repair gene variants and prostate cancer susceptibility using the iCOGS-genotyping array.
Br J Cancer. 2016; 114(8):945-52 [PubMed] Related Publications
BACKGROUND: Germline mutations within DNA-repair genes are implicated in susceptibility to multiple forms of cancer. For prostate cancer (PrCa), rare mutations in BRCA2 and BRCA1 give rise to moderately elevated risk, whereas two of B100 common, low-penetrance PrCa susceptibility variants identified so far by genome-wide association studies implicate RAD51B and RAD23B.
METHODS: Genotype data from the iCOGS array were imputed to the 1000 genomes phase 3 reference panel for 21 780 PrCa cases and 21 727 controls from the Prostate Cancer Association Group to Investigate Cancer Associated Alterations in the Genome (PRACTICAL) consortium. We subsequently performed single variant, gene and pathway-level analyses using 81 303 SNPs within 20 Kb of a panel of 179 DNA-repair genes.
RESULTS: Single SNP analyses identified only the previously reported association with RAD51B. Gene-level analyses using the SKAT-C test from the SNP-set (Sequence) Kernel Association Test (SKAT) identified a significant association with PrCa for MSH5. Pathway-level analyses suggested a possible role for the translesion synthesis pathway in PrCa risk and Homologous recombination/Fanconi Anaemia pathway for PrCa aggressiveness, even though after adjustment for multiple testing these did not remain significant.
CONCLUSIONS: MSH5 is a novel candidate gene warranting additional follow-up as a prospective PrCa-risk locus. MSH5 has previously been reported as a pleiotropic susceptibility locus for lung, colorectal and serous ovarian cancers.

Chi Y, Huang S, Peng H, et al.
Critical role of CDK11(p58) in human breast cancer growth and angiogenesis.
BMC Cancer. 2015; 15:701 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: A capillary network is needed in cancer growth and metastasis. Induction of angiogenesis represents one of the major hallmarks of cancer. CDK11(p58), a Ser/Thr kinase that belongs to the Cell Division Cycle 2-like 1 (CDC2L1) subfamily is associated with cell cycle progression, tumorigenesis, sister chromatid cohesion and apoptotic signaling. However, its role in breast cancer proliferation and angiogenesis remains unclear.
METHODS: Tumorigenicity assays and blood vessel assessment in athymic mice were used to assess the function of CDK11(p58) in tumor proliferation and angiogenesis. CCK-8 assay was used to detect breast cancer cell growth. Immunohistochemistry was used to detect the expression of vascular endothelial growth factor (VEGF), CD31 and CD34 in CDK11 positive patient breast cancer tissues. Dual-Luciferase array was used to analyze the function of CDK11(p58) in the regulation of VEGF promoter activity. Western blot was used to detect related protein expression levels.
RESULTS: CDK11(p58) inhibited breast cancer growth and angiogenesis in breast cancer cells and in nude mice transplanted with tumors. Immunohistochemistry confirmed that CDK11(p58) was negatively associated with angiogenesis-related proteins such as VEGF, CD31 and CD34 in breast cancer patients. Real-time PCR and dual-luciferase assay showed CDK11(p58) inhibited the mRNA levels of VEGF and the promoter activity of VEGF. As CDK11(p58) is a Ser/Thr kinase, the kinase-dead mutant failed to inhibit VEGF mRNA and promoter activity. Western blot analysis showed the same pattern of related protein expression. The data suggested angiogenesis inhibition was dependent on CDK11(p58) kinase activity.
CONCLUSION: This study indicates that CDK11(p58) inhibits the growth and angiogenesis of breast cancer dependent on its kinase activity.

Chien J, Sicotte H, Fan JB, et al.
TP53 mutations, tetraploidy and homologous recombination repair defects in early stage high-grade serous ovarian cancer.
Nucleic Acids Res. 2015; 43(14):6945-58 [PubMed] Free Access to Full Article Related Publications
To determine early somatic changes in high-grade serous ovarian cancer (HGSOC), we performed whole genome sequencing on a rare collection of 16 low stage HGSOCs. The majority showed extensive structural alterations (one had an ultramutated profile), exhibited high levels of p53 immunoreactivity, and harboured a TP53 mutation, deletion or inactivation. BRCA1 and BRCA2 mutations were observed in two tumors, with nine showing evidence of a homologous recombination (HR) defect. Combined Analysis with The Cancer Genome Atlas (TCGA) indicated that low and late stage HGSOCs have similar mutation and copy number profiles. We also found evidence that deleterious TP53 mutations are the earliest events, followed by deletions or loss of heterozygosity (LOH) of chromosomes carrying TP53, BRCA1 or BRCA2. Inactivation of HR appears to be an early event, as 62.5% of tumours showed a LOH pattern suggestive of HR defects. Three tumours with the highest ploidy had little genome-wide LOH, yet one of these had a homozygous somatic frame-shift BRCA2 mutation, suggesting that some carcinomas begin as tetraploid then descend into diploidy accompanied by genome-wide LOH. Lastly, we found evidence that structural variants (SV) cluster in HGSOC, but are absent in one ultramutated tumor, providing insights into the pathogenesis of low stage HGSOC.

Takahashi H, Nishimura J, Kagawa Y, et al.
Significance of Polypyrimidine Tract-Binding Protein 1 Expression in Colorectal Cancer.
Mol Cancer Ther. 2015; 14(7):1705-16 [PubMed] Related Publications
Polypyrimidine tract-binding protein (PTBP1) is an RNA-binding protein with various molecular functions related to RNA metabolism and a major repressive regulator of alternative splicing, causing exon skipping in numerous alternatively spliced pre-mRNAs. Here, we have investigated the role of PTBP1 in colorectal cancer. PTBP1 expression levels were significantly overexpressed in cancerous tissues compared with corresponding normal mucosal tissues. We also observed that PTBP1 expression levels, c-MYC expression levels, and PKM2:PKM1 ratio were positively correlated in colorectal cancer specimens. Moreover, PTBP1 expression levels were positively correlated to poor prognosis and lymph node metastasis. In analyses of colorectal cancer cells using siRNA for PTBP1, we observed that PTBP1 affects cell invasion, which was partially correlated to CD44 splicing, and this correlation was also confirmed in clinical samples. PTBP1 expression also affected anchorage-independent growth in colorectal cancer cell lines. PTBP1 expression also affected cell proliferation. Using time-lapse imaging analysis, PTBP1 was implicated in prolonged G2-M phase in HCT116 cells. As for the mechanism of prolonged G2-M phase in HCT116 siPTBP1 cells, Western blotting revealed that PTBP1 expression level was correlated to CDK11(p58) expression level, which was reported to play an important role on progression to complete mitosis. These findings indicated that PTBP1 is a potential therapeutic target for colorectal cancer.

Hatano K, Kumar B, Zhang Y, et al.
A functional screen identifies miRNAs that inhibit DNA repair and sensitize prostate cancer cells to ionizing radiation.
Nucleic Acids Res. 2015; 43(8):4075-86 [PubMed] Free Access to Full Article Related Publications
MicroRNAs (miRNAs) have been implicated in DNA repair pathways through transcriptional responses to DNA damaging agents or through predicted miRNA regulation of DNA repair genes. We hypothesized that additional DNA damage regulating miRNAs could be identified by screening a library of 810 miRNA mimetics for the ability to alter cellular sensitivity to ionizing radiation (IR). A prostate cancer Metridia luciferase cell model was applied to examine the effects of individual miRNAs on IR sensitivity. A large percentage of miRNA mimetics were found to increase cellular sensitivity to IR, while a smaller percentage were protective. Two of the most potent IR sensitizing miRNAs, miR-890 and miR-744-3p, significantly delayed IR induced DNA damage repair. Both miRNAs inhibited the expression of multiple components of DNA damage response and DNA repair. miR-890 directly targeted MAD2L2, as well as WEE1 and XPC, where miR-744-3p directly targeted RAD23B. Knock-down of individual miR-890 targets by siRNA was not sufficient to ablate miR-890 radiosensitization, signifying that miR-890 functions by regulating multiple DNA repair genes. Intratumoral delivery of miR-890 mimetics prior to IR therapy significantly enhanced IR therapeutic efficacy. These results reveal novel miRNA regulation of DNA repair and identify miR-890 as a potent IR sensitizing agent.

Dasmahapatra G, Patel H, Friedberg J, et al.
In vitro and in vivo interactions between the HDAC6 inhibitor ricolinostat (ACY1215) and the irreversible proteasome inhibitor carfilzomib in non-Hodgkin lymphoma cells.
Mol Cancer Ther. 2014; 13(12):2886-97 [PubMed] Free Access to Full Article Related Publications
Interactions between the HDAC6 inhibitor ricolinostat (ACY1215) and the irreversible proteasome inhibitor carfilzomib were examined in non-Hodgkin lymphoma (NHL) models, including diffuse large B-cell lymphoma (DLBCL), mantle cell lymphoma (MCL), and double-hit lymphoma cells. Marked in vitro synergism was observed in multiple cell types associated with activation of cellular stress pathways (e.g., JNK1/2, ERK1/2, and p38) accompanied by increases in DNA damage (γH2A.X), G2-M arrest, and the pronounced induction of mitochondrial injury and apoptosis. Combination treatment with carfilzomib and ricolinostat increased reactive oxygen species (ROS), whereas the antioxidant TBAP attenuated DNA damage, JNK activation, and cell death. Similar interactions occurred in bortezomib-resistant and double-hit DLBCL, MCL, and primary DLBCL cells, but not in normal CD34(+) cells. However, ricolinostat did not potentiate inhibition of chymotryptic activity by carfilzomib. shRNA knockdown of JNK1 (but not MEK1/2), or pharmacologic inhibition of p38, significantly reduced carfilzomib-ricolinostat lethality, indicating a functional contribution of these stress pathways to apoptosis. Combined exposure to carfilzomib and ricolinostat also markedly downregulated the cargo-loading protein HR23B. Moreover, HR23B knockdown significantly increased carfilzomib- and ricolinostat-mediated lethality, suggesting a role for this event in cell death. Finally, combined in vivo treatment with carfilzomib and ricolinostat was well tolerated and significantly suppressed tumor growth and increased survival in an MCL xenograft model. Collectively, these findings indicate that carfilzomib and ricolinostat interact synergistically in NHL cells through multiple stress-related mechanisms, and suggest that this strategy warrants further consideration in NHL.

Guo H, Bassig BA, Lan Q, et al.
Polymorphisms in DNA repair genes, hair dye use, and the risk of non-Hodgkin lymphoma.
Cancer Causes Control. 2014; 25(10):1261-70 [PubMed] Free Access to Full Article Related Publications
PURPOSE: Genetic polymorphisms in DNA repair genes and hair dye use may both have a role in the development of non-Hodgkin lymphoma (NHL). We aimed to examine the interaction between variants in DNA repair genes and hair dye use with risk of NHL in a population-based case-control study of Connecticut women.
METHODS: We examined 24 single nucleotide polymorphisms in 16 DNA repair genes among 518 NHL cases and 597 controls and evaluated the associations between hair dye use and risk of overall NHL and common NHL subtypes, stratified by genotype, using unconditional logistic regression.
RESULTS: Women who used hair dye before 1980 had a significantly increased risk of NHL, particularly for the follicular lymphoma (FL) subtype, but not for diffuse large B-cell lymphoma. The following genotypes in combination with hair dye use before 1980 were associated with FL risk: BRCA2 rs144848 AC+CC [odds ratio (OR) (95% confidence interval (CI)) 3.28(1.27-8.50)], WRN rs1346044 TT [OR(95% CI) 2.70(1.30-5.65)], XRCC3 rs861539 CT+TT [OR(95% CI) 2.76(1.32-5.77)], XRCC4 rs1805377 GG [OR(95% CI) 2.07(1.10-3.90)] and rs1056503 TT [OR(95% CI) 2.17(1.16-4.07)], ERCC1 rs3212961 CC [OR(95% CI) 1.93(1.00-3.72)], RAD23B rs1805329 CC [OR(95% CI) 2.28(1.12-4.64)], and MGMT rs12917 CC, rs2308321 AA, and rs2308327 AA genotypes [OR(95% CI) 1.96(1.06-3.63), 2.02(1.09-3.75), and 2.23(1.16-4.29), respectively]. In addition, a significant interaction with risk of overall NHL was observed between WRN rs1346044 and hair dye use before 1980 (p(interaction) = 0.032).
CONCLUSIONS: Our results indicated that genetic variation in DNA repair genes modifies susceptibility to NHL in relation to hair dye use, particularly for the FL subtype and in women who began using hair dye before 1980. Further studies are needed to confirm these observations.

Chi Y, Huang S, Wang L, et al.
CDK11p58 inhibits ERα-positive breast cancer invasion by targeting integrin β3 via the repression of ERα signaling.
BMC Cancer. 2014; 14:577 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: CDK11(p58), a Ser/Thr kinase that belongs to the cell division cycle 2-like 1 (CDC2L1) subfamily, is associated with cell cycle progression, tumorigenesis and apoptotic signaling. CDK11(p58) is also involved in the regulation of steroid receptors, such as androgen and estrogen receptors. We previously found that CDK11(p58) was abnormally expressed in prostate cancer. However, its role in breast cancer remains unclear.
METHODS: CDK11(p58) expression was evaluated by immunohistochemical staining in a tissue array. A Transwell assay was used to detect invasion and metastasis in breast cancer cells. The TaqMan® Metastasis Gene Expression Assay was used to search for potential downstream factors in the CDK11(p58) signaling pathway. qRT-PCR was used to evaluate mRNA levels, and the dual luciferase array was used to analyze promoter activity. Western blotting was used to detect the protein level.
RESULTS: CDK11(p58) expression was negatively correlated with node status (P = 0.012), relapse status (P = 0.002) and metastasis status (P = 0.023). Kaplan-Meier survival curves indicated that the disease-free survival (DFS) was significantly poor in breast cancer patients with low CDK11 expression. Interestingly, using the breast cancer cell lines ZR-75-30 and MDA-MB-231, we found that CDK11(p58) was capable of repressing the migration and invasion of ERα-positive breast cancer cells, but not ERα-negative breast cancer cells, in a kinase-dependent manner. Gene expression assays demonstrated that integrin β3 mRNA was dramatically repressed by CDK11(p58), and luciferase results confirmed that the integrin β3 promoter was inhibited by CDK11(p58) through ERα repression. The expression of integrin β3 was highly related to ERα signaling; ERα overexpression stimulated integrin β3 expression, whereas siRNA-mediated knockdown of ERα attenuated integrin β3 expression.
CONCLUSIONS: These data indicate that CDK11(p58) is an anti-metastatic gene in ERα-positive breast cancer and that the regulation of integrin β3 by CDK11(p58) via the repression of ERα signaling may constitute part of a signaling pathway underlying breast cancer invasion.

Steck SE, Butler LM, Keku T, et al.
Nucleotide excision repair gene polymorphisms, meat intake and colon cancer risk.
Mutat Res. 2014; 762:24-31 [PubMed] Free Access to Full Article Related Publications
PURPOSE: Much of the DNA damage from colon cancer-related carcinogens, including heterocyclic amines (HCA) and polycyclic aromatic hydrocarbons (PAH) from red meat cooked at high temperature, are repaired by the nucleotide excision repair (NER) pathway. Thus, we examined whether NER non-synonymous single nucleotide polymorphisms (nsSNPs) modified the association between red meat intake and colon cancer risk.
METHODS: The study consists of 244 African-American and 311 white colon cancer cases and population-based controls (331 African Americans and 544 whites) recruited from 33 counties in North Carolina from 1996 to 2000. Information collected by food frequency questionnaire on meat intake and preparation methods were used to estimate HCA and benzo(a)pyrene (BaP, a PAH) intake. We tested 7 nsSNPs in 5 NER genes: XPC A499V and K939Q, XPD D312N and K751Q, XPF R415Q, XPG D1104H, and RAD23B A249V. Adjusted odds ratios (OR) and 95% confidence intervals (CI) were calculated using unconditional logistic regression.
RESULTS: Among African Americans, we observed a statistically significant positive association between colon cancer risk and XPC 499 AV+VV genotype (OR=1.7, 95% CI: 1.1, 2.7, AA as referent), and an inverse association with XPC 939 QQ (OR=0.3, 95%CI: 0.2, 0.8, KK as referent). These associations were not observed among whites. For both races combined, there was interaction between the XPC 939 genotype, well-done red meat intake and colon cancer risk (OR=1.5, 95% CI=1.0, 2.2 for high well-done red meat and KK genotype as compared to low well-done red meat and KK genotype, pinteraction=0.05).
CONCLUSIONS: Our data suggest that NER nsSNPs are associated with colon cancer risk and may modify the association between well-done red meat intake and colon cancer risk.

Do H, Wong NC, Murone C, et al.
A critical re-assessment of DNA repair gene promoter methylation in non-small cell lung carcinoma.
Sci Rep. 2014; 4:4186 [PubMed] Free Access to Full Article Related Publications
DNA repair genes that have been inactivated by promoter methylation offer potential therapeutic targets either by targeting the specific repair deficiency, or by synthetic lethal approaches. This study evaluated promoter methylation status for eight selected DNA repair genes (ATM, BRCA1, ERCC1, MGMT, MLH1, NEIL1, RAD23B and XPC) in 56 non-small cell lung cancer (NSCLC) tumours and 11 lung cell lines using the methylation-sensitive high resolution melting (MS-HRM) methodology. Frequent methylation in NEIL1 (42%) and infrequent methylation in ERCC1 (2%) and RAD23B (2%) are reported for the first time in NSCLC. MGMT methylation was detected in 13% of the NSCLCs. Contrary to previous studies, methylation was not detected in ATM, BRCA1, MLH1 and XPC. Data from The Cancer Genome Atlas (TCGA) was consistent with these findings. The study emphasises the importance of using appropriate methodology for accurate assessment of promoter methylation.

Kim Y, Kim J, Jang SW, Ko J
The role of sLZIP in cyclin D3-mediated negative regulation of androgen receptor transactivation and its involvement in prostate cancer.
Oncogene. 2015; 34(2):226-36 [PubMed] Related Publications
Androgen and the androgen receptor (AR) have important roles in prostate cancer (PCa) development, and androgen ablation has been the main therapeutic option for the treatment of PCa. However, the transition mechanism from androgen-dependent to -independent PCa after androgen depletion remains unclear. We investigated the distinct roles of small leucine zipper protein (sLZIP) in proliferation of androgen-dependent and -independent PCa cells. Cyclin D3 is known to interact with AR and attenuates the ligand-dependent function of AR in PCa cells. sLZIP regulates the transcription of cyclin D3 by binding directly to the AP-1 region in the cyclin D3 promoter. sLZIP represses AR transcriptional activity by interaction with AR that is phosphorylated by cyclin D3/cyclin-dependent kinase11(p58), leading to the suppression of androgen-dependent proliferation of PCa cells. The expression level of sLZIP is elevated in androgen-independent PCa cells and advanced human prostate tumors. Knockdown of endogenous sLZIP suppresses proliferation of androgen-independent PCa cells. LNCaP cells transformed to androgen-independent PCa cells exhibit increased expressions of sLZIP and cyclin D3. Tumor formation is inhibited in nude mouse xenografts from two androgen-independent PCa cells that are stably transfected with sh-sLZIP. Our findings indicate that sLZIP negatively regulates AR transactivation in androgen-dependent PCa cells and functions as a positive regulator in tumor progression of androgen-independent PCa. sLZIP contributes to the malignant phenotype of PCa and constitutes a novel therapeutic target for human PCa.

Santos LS, Gomes BC, Gouveia R, et al.
The role of CCNH Val270Ala (rs2230641) and other nucleotide excision repair polymorphisms in individual susceptibility to well-differentiated thyroid cancer.
Oncol Rep. 2013; 30(5):2458-66 [PubMed] Related Publications
Well-differentiated thyroid cancer (DTC) is the most common form of thyroid cancer (TC); however, with the exception of radiation exposure, its etiology remains largely unknown. Several single nucleotide polymorphisms (SNPs) have previously been implicated in DTC risk. Nucleotide excision repair (NER) polymorphisms, despite having been associated with cancer risk at other locations, have received little attention in the context of thyroid carcinogenesis. In order to evaluate the role of NER pathway SNPs in DTC susceptibility, we performed a case-control study in 106 Caucasian Portuguese DTC patients and 212 matched controls. rs2230641 (CCNH), rs2972388 (CDK7), rs1805329 (RAD23B), rs3212986 (ERCC1), rs1800067 (ERCC4), rs17655, rs2227869 (ERCC5), rs4253211 and rs2228529 (ERCC6) were genotyped using TaqMan® methodology, while conventional PCR-RFLP was employed for rs2228000 and rs2228001 (XPC). When considering all DTC cases, only rs2230641 (CCNH) was associated with DTC risk; a consistent increase in overall DTC risk was observed for both the heterozygous genotype (OR=1.89, 95% CI=1.14-3.14) and the variant allele carriers (OR=1.79, 95% CI=1.09-2.93). Histological stratification analysis confirmed an identical effect on follicular TC (OR=2.72, 95% CI=1.19-6.22, for heterozygous; OR=2.44, 95% CI=1.07‑5.55, for variant allele carriers). Considering papillary TC, the rs2228001 (XPC) variant genotype was associated with increased risk (OR=2.33, 95% CI=1.05-5.16), while a protective effect was observed for rs2227869 (ERCC5) (OR=0.26, 95% CI=0.08‑0.90, for heterozygous; OR=0.25, 95% CI=0.07-0.86, for variant allele carriers). No further significant results were observed. Our results suggest that NER polymorphisms such as rs2230641 (CCNH) and, possibly, rs2227869 (ERCC5) and rs2228001 (XPC), may influence DTC susceptibility. However, larger studies are required to confirm these results.

Pérez-Mayoral J, Pacheco-Torres AL, Morales L, et al.
Genetic polymorphisms in RAD23B and XPC modulate DNA repair capacity and breast cancer risk in Puerto Rican women.
Mol Carcinog. 2013; 52 Suppl 1:E127-38 [PubMed] Free Access to Full Article Related Publications
Studies have shown that DNA repair capacity (DRC) is significantly decreased in breast cancer patients, but the molecular causes of inter-individual variation in DRC are unknown. We hypothesized that genetic variation in the nucleotide excision repair pathway genes can modulate DRC and breast cancer risk in Puerto Rican women. A total of 228 breast cancer cases and 418 controls were recruited throughout Puerto Rico. For all study participants, eight single nucleotide polymorphisms (SNPs) in the genes XPC, XPD, and RAD23B were genotyped using a TaqMan PCR, and the DRC levels of UV induced-DNA damage was measured in peripheral lymphocytes using a host cell reactivation assay. After adjustment for confounders, RAD23B rs1805329 (Ala249Val) was found to be significantly associated with breast cancer risk under all models tested (P < 0.001). There was also a significant association between breast cancer risk and RAD23B rs10739234 (intronic) under the recessive model (P = 0.003, OR: 2.72, 95% CI: 1.40-5.30). In cases, there was a statistically significant difference in mean DRC per genotype for RAD23B rs1805329 (P < 0.001) and XPC rs2607775 (P = 0.002). When we modeled the combined effect of multiple SNPs that each independently affected DRC on cancer risk, we observed incremental augmentations in risk with increasing number of risk genotypes at those loci (P overall model <0.001). The increase in adverse genotypes was also correlated with a progressive decrease in DRC values. Our data indicate an additive effect of the NER SNPs on DRC and breast cancer risk in Puerto Rican women.

O'Brien KM, Orlow I, Antonescu CR, et al.
Gastrointestinal stromal tumors, somatic mutations and candidate genetic risk variants.
PLoS One. 2013; 8(4):e62119 [PubMed] Free Access to Full Article Related Publications
Gastrointestinal stromal tumors (GISTs) are rare but treatable soft tissue sarcomas. Nearly all GISTs have somatic mutations in either the KIT or PDGFRA gene, but there are no known inherited genetic risk factors. We assessed the relationship between KIT/PDGFRA mutations and select deletions or single nucleotide polymorphisms (SNPs) in 279 participants from a clinical trial of adjuvant imatinib mesylate. Given previous evidence that certain susceptibility loci and carcinogens are associated with characteristic mutations, or "signatures" in other cancers, we hypothesized that the characteristic somatic mutations in the KIT and PDGFRA genes in GIST tumors may similarly be mutational signatures that are causally linked to specific mutagens or susceptibility loci. As previous epidemiologic studies suggest environmental risk factors such as dioxin and radiation exposure may be linked to sarcomas, we chose 208 variants in 39 candidate genes related to DNA repair and dioxin metabolism or response. We calculated adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for the association between each variant and 7 categories of tumor mutation using logistic regression. We also evaluated gene-level effects using the sequence kernel association test (SKAT). Although none of the association p-values were statistically significant after adjustment for multiple comparisons, SNPs in CYP1B1 were strongly associated with KIT exon 11 codon 557-8 deletions (OR = 1.9, 95% CI: 1.3-2.9 for rs2855658 and OR = 1.8, 95% CI: 1.2-2.7 for rs1056836) and wild type GISTs (OR = 2.7, 95% CI: 1.5-4.8 for rs1800440 and OR = 0.5, 95% CI: 0.3-0.9 for rs1056836). CYP1B1 was also associated with these mutations categories in the SKAT analysis (p = 0.002 and p = 0.003, respectively). Other potential risk variants included GSTM1, RAD23B and ERCC2. This preliminary analysis of inherited genetic risk factors for GIST offers some clues about the disease's genetic origins and provides a starting point for future candidate gene or gene-environment research.

Milde T, Lodrini M, Savelyeva L, et al.
HD-MB03 is a novel Group 3 medulloblastoma model demonstrating sensitivity to histone deacetylase inhibitor treatment.
J Neurooncol. 2012; 110(3):335-48 [PubMed] Related Publications
Medulloblastomas are the most common malignant brain tumors in childhood. Emerging evidence suggests that medulloblastoma comprises at least four distinct diseases (WNT, SHH, Group 3 and 4) with different biology, clinical presentation, and outcome, with especially poor prognosis in Group 3. The tight connection of biology and clinical behavior in patients emphasizes the need for subgroup-specific preclinical models in order to develop treatments tailored to each subgroup. Herein we report on the novel cell line HD-MB03, isolated from tumor material of a patient with metastasized Group 3 medulloblastoma, and preclinical testing of different histone deacetylase inhibitors (HDACis) in this model. HD-MB03 cells grow long term in vitro and form metastatic tumors in vivo upon orthotopic transplantation. HD-MB03 cells reflect the original Group 3 medulloblastoma at the histological and molecular level, showing large cell morphology, similar expression patterns for markers Ki67, p53, and glial fibrillary acidic protein (GFAP), a gene expression profile most closely matching Group 3 medulloblastomas, and persistence of typical molecular alterations, i.e., isochromosome 17q [i(17q)] and MYC amplification. Protein expression analysis of HDACs 2, 5, 8, and 9 as well as the predictive marker HR23B showed intermediate to strong expression, suggesting sensitivity to HDACis. Indeed, treatment with HDACis Helminthosporium carbonum (HC)-toxin, vorinostat, and panobinostat revealed high sensitivity to this novel drug class, as well as a radiation-sensitizing effect with significantly increased cell death upon concomitant treatment. In summary, our data indicate that HD-MB03 is a suitable preclinical model for Group 3 medulloblastoma, and HDACis could represent a therapeutic option for this subgroup.

Xu J, Mo Z, Ye D, et al.
Genome-wide association study in Chinese men identifies two new prostate cancer risk loci at 9q31.2 and 19q13.4.
Nat Genet. 2012; 44(11):1231-5 [PubMed] Free Access to Full Article Related Publications
Prostate cancer risk-associated variants have been reported in populations of European descent, African-Americans and Japanese using genome-wide association studies (GWAS). To systematically investigate prostate cancer risk-associated variants in Chinese men, we performed the first GWAS in Han Chinese. In addition to confirming several associations reported in other ancestry groups, this study identified two new risk-associated loci for prostate cancer on chromosomes 9q31.2 (rs817826, P = 5.45 × 10(-14)) and 19q13.4 (rs103294, P = 5.34 × 10(-16)) in 4,484 prostate cancer cases and 8,934 controls. The rs103294 marker at 19q13.4 is in strong linkage equilibrium with a 6.7-kb germline deletion that removes the first six of seven exons in LILRA3, a gene regulating inflammatory response, and was significantly associated with the mRNA expression of LILRA3 in T cells (P < 1 × 10(-4)). These findings may advance the understanding of genetic susceptibility to prostate cancer.

Ramos-Espinosa P, Rojas E, Valverde M
Differential DNA damage response to UV and hydrogen peroxide depending of differentiation stage in a neuroblastoma model.
Neurotoxicology. 2012; 33(5):1086-95 [PubMed] Related Publications
DNA is a frequent target of oxidative damage, and DNA damage removal is therefore a crucial process in prevention of or recovery from degenerative diseases. DNA repair is an essential system for maintaining the inherited nucleotide sequence of genomic DNA over time. Cells engage in efficient DNA repair mechanisms, the activity of which can vary depending on the type of lesion and the developmental stage. Base excision repair (BER) and nucleotide excision repair (NER) are the major repair pathways addressed in this study. BER is the principal mechanism for repair of DNA oxidative lesions, while NER is the mechanism for repair of a variety of helix-distorting lesions such as those caused by UV radiation. Recent studies suggest that NER plays a cooperative role in removal of oxidative lesions. Little is known about the roles of DNA damage sensors and repair factors in terminally differentiated, non-proliferating cells such as neurons, which are vulnerable to oxidative damage from reactive oxygen species generated by endogenous or exogenous agents. We used the human neuroblastoma MSN cell model to investigate whether terminally differentiated neuronal cells respond to lesions cause in the DNA helix, such as UV-induced CPD and the major DNA oxidative lesion 8OHdG, and thereby clarify the role of NER capacity. We observed differences in DNA damage removal depending on the challenge insult and the differentiation state. Differentiated MSN cells, compared with undifferentiated cells, showed greater sensitivity to UVC and decreased DNA damage over time. In contrast, undifferentiated cells displayed genotoxicity induced by oxidative insult and tended to accumulate DNA damage and 8OHdG lesions over time. Our findings suggest the participation of GG-NER, TC-NER and BER proteins in the removal of 8-OHG and CPDs indicating a dynamic role in overall response to damage.

Gao D, Bambang IF, Putti TC, et al.
ERp29 induces breast cancer cell growth arrest and survival through modulation of activation of p38 and upregulation of ER stress protein p58IPK.
Lab Invest. 2012; 92(2):200-13 [PubMed] Related Publications
Endoplasmic reticulum protein 29 (ERp29) is an ER luminal protein that has a role in protein unfolding and secretion, but its role in cancer is unclear. Recently, we reported that overexpression of ERp29 significantly inhibited cell proliferation and prevented tumorigenesis in highly proliferative MDA-MB-231 breast cancer cells. Here, we show that ERp29-induced cancer cell growth arrest is modulated by the interplay between the concomitant phosphorylation of p38 and upregulation of the inhibitor of the interferon-induced, double-stranded RNA-activated protein kinase, p58(IPK). In this cell model, ERp29 overexpression significantly downregulates modulators of cell proliferation, namely urokinase plasminogen activator receptor, β(1)-integrin and epidermal growth factor receptor. Furthermore, ERp29 significantly (P<0.001) increases phosphorylation of p38 (p-p38) and reduces matrix metalloproteinase-9 secretion. The role of ERp29 in upregulating cyclin-dependent kinase inhibitors (p15 and p21) and in downregulating cyclin D(2) is demonstrated in slowly proliferating ERp29-overexpressing MDA-MB-231 cells, whereas the opposite response was observed in ERp29-knockdown MCF-7 cells. Pharmacological inhibition of p-p38 downregulates p15 and p21 and inhibits eIF2α phosphorylation, indicating a role for p-p38 in this process. Furthermore, p58(IPK) expression was increased in ERp29-overexpressing MDA-MB-231 cells and highly decreased in ERp29-knockdown MCF-7 cells. This upregulation of p58(IPK) by ERp29 suppresses the activation of p-p38/p-PERK/p-eIF2α by repressing eIF2α phosphorylation. In fact, reduction of p58(IPK) expression by RNA interference stimulated eIF2α phosphorylation. The repression of eIF2α phosphorylation by p58(IPK) prevents ERp29-transfected cells from undergoing ER-dependent apoptosis driven by the activation of ATF4/CHOP/caspase-3. Hence, the interplay between p38 phosphorylation and p58(IPK) upregulation has key roles in modulating ERp29-induced cell-growth arrest and survival.

Tomoda T, Nouso K, Sakai A, et al.
Genetic risk of hepatocellular carcinoma in patients with hepatitis C virus: a case control study.
J Gastroenterol Hepatol. 2012; 27(4):797-804 [PubMed] Related Publications
BACKGROUND AND AIM: Chronic hepatitis C virus (HCV) infection is a well known risk factor for hepatocellular carcinoma (HCC). The aim of this study is to elucidate the genetic risk of development and recurrence of HCC in patients with HCV.
METHODS: A total of 468 patients with HCV, including 265 with HCC were enrolled. We genotyped 88 single nucleotide polymorphisms (SNPs) in 81 genes expected to influence hepatocarcinogenesis using the iPLEX assay. Risk of HCC was clarified by stratifying patients into risk groups based on the multiplied odds ratio (MOR) for SNPs associated with HCC, and the cumulative effects on the development and recurrence of HCC were analyzed.
RESULTS: Six SNPs associated with risk of HCC were identified (OR range: 0.29-1.76). These included novel SNPs for hepatocarcinogenesis with HCV CCND2 rs1049606, RAD23B rs1805329, CEP164 rs573455, and GRP78rs430397 in addition to the known SNPs MDM2 rs2279744 and ALDH2 rs671. MOR analysis revealed that the highest risk group exerted about a 19-fold higher relative OR compared with the lowest risk group (P = 1.08 × 10(-5)). Predicted 10-year HCC risk ranged from 1.7% to 96% depending on the risk group and the extent of fibrosis. Recurrence-free survival of radiofrequency ablation-treated HCC in the high risk group (n = 53) was lower than that of low risk group (n = 58, P = 0.038).
CONCLUSION: Single nucleotide polymorphisms of CCND2, RAD23B, GRP78, CEP164, MDM2, and ALDH2 genes were significantly associated with development and recurrence of HCC in Japanese patients with HCV.

Long Q, Johnson BA, Osunkoya AO, et al.
Protein-coding and microRNA biomarkers of recurrence of prostate cancer following radical prostatectomy.
Am J Pathol. 2011; 179(1):46-54 [PubMed] Free Access to Full Article Related Publications
An important challenge in prostate cancer research is to develop effective predictors of tumor recurrence following surgery to determine whether immediate adjuvant therapy is warranted. To identify biomarkers predictive of biochemical recurrence, we isolated the RNA from 70 formalin-fixed, paraffin-embedded radical prostatectomy specimens with known long-term outcomes to perform DASL expression profiling with a custom panel that we designed of 522 prostate cancer-relevant genes. We identified a panel of 10 protein-coding genes and two miRNA genes (RAD23B, FBP1, TNFRSF1A, CCNG2, NOTCH3, ETV1, BID, SIM2, LETMD1, ANXA1, miR-519d, and miR-647) that could be used to separate patients with and without biochemical recurrence (P < 0.001), as well as for the subset of 42 Gleason score 7 patients (P < 0.001). We performed an independent validation analysis on 40 samples and found that the biomarker panel was also significant at prediction of biochemical recurrence for all cases (P = 0.013) and for a subset of 19 Gleason score 7 cases (P = 0.010), both of which were adjusted for relevant clinical information including T-stage, prostate-specific antigen, and Gleason score. Importantly, these biomarkers could significantly predict clinical recurrence for Gleason score 7 patients. These biomarkers may increase the accuracy of prognostication following radical prostatectomy using formalin-fixed specimens.

Liu RY, Dong Z, Liu J, et al.
Role of eIF3a in regulating cisplatin sensitivity and in translational control of nucleotide excision repair of nasopharyngeal carcinoma.
Oncogene. 2011; 30(48):4814-23 [PubMed] Free Access to Full Article Related Publications
Translational control at the initiation step has been recognized as a major and important regulatory mechanism of gene expression. Eukaryotic initiation factor-3a (eIF3a), a putative subunit of the eIF3 complex, has recently been shown to have an important role in regulating the translation of a subset of mRNAs and is found to correlate with the prognosis of cancers. In this study, using nasopharyngeal carcinoma (NPC) cells as a model system, we tested the hypothesis that eIF3a negatively regulates the synthesis of nucleotide excision repair (NER) proteins, and, in turn, cellular response to treatments with DNA-damaging agents such as cisplatin (cis-dichlorodiammine platinum(II) (CDDP)). We found that a CDDP-sensitive sub-clone S16 isolated through limited dilution from an NPC cell line CNE-2 has increased eIF3a expression. Knocking down its expression in S16 cells increased cellular resistance to CDDP, NER activity and synthesis of the NER proteins XPA, XPC, RAD23B and RPA32. Altering eIF3a expression also changed the cellular response to CDDP and UV treatment in other NPC cell lines. Taken together, we conclude that eIF3a has an important role in the CDDP response and in NER activity of NPCs by suppressing the synthesis of NER proteins.

Fuss JO, Tainer JA
XPB and XPD helicases in TFIIH orchestrate DNA duplex opening and damage verification to coordinate repair with transcription and cell cycle via CAK kinase.
DNA Repair (Amst). 2011; 10(7):697-713 [PubMed] Free Access to Full Article Related Publications
Helicases must unwind DNA at the right place and time to maintain genomic integrity or gene expression. Biologically critical XPB and XPD helicases are key members of the human TFIIH complex; they anchor CAK kinase (cyclinH, MAT1, CDK7) to TFIIH and open DNA for transcription and for repair of duplex distorting damage by nucleotide excision repair (NER). NER is initiated by arrested RNA polymerase or damage recognition by XPC-RAD23B with or without DDB1/DDB2. XP helicases, named for their role in the extreme sun-mediated skin cancer predisposition xeroderma pigmentosum (XP), are then recruited to asymmetrically unwind dsDNA flanking the damage. XPB and XPD genetic defects can also cause premature aging with profound neurological defects without increased cancers: Cockayne syndrome (CS) and trichothiodystrophy (TTD). XP helicase patient phenotypes cannot be predicted from the mutation position along the linear gene sequence and adjacent mutations can cause different diseases. Here we consider the structural biology of DNA damage recognition by XPC-RAD23B, DDB1/DDB2, RNAPII, and ATL, and of helix unwinding by the XPB and XPD helicases plus the bacterial repair helicases UvrB and UvrD in complex with DNA. We then propose unified models for TFIIH assembly and roles in NER. Collective crystal structures with NMR and electron microscopy results reveal functional motifs, domains, and architectural elements that contribute to biological activities: damaged DNA binding, translocation, unwinding, and ATP driven changes plus TFIIH assembly and signaling. Coupled with mapping of patient mutations, these combined structural analyses provide a framework for integrating and unifying the rich biochemical and cellular information that has accumulated over forty years of study. This integration resolves puzzles regarding XP helicase functions and suggests that XP helicase positions and activities within TFIIH detect and verify damage, select the damaged strand for incision, and coordinate repair with transcription and cell cycle through CAK signaling.

Fletcher O, Johnson N, Orr N, et al.
Novel breast cancer susceptibility locus at 9q31.2: results of a genome-wide association study.
J Natl Cancer Inst. 2011; 103(5):425-35 [PubMed] Related Publications
BACKGROUND: Genome-wide association studies have identified several common genetic variants associated with breast cancer risk. It is likely, however, that a substantial proportion of such loci have not yet been discovered.
METHODS: We compared 296,114 tagging single-nucleotide polymorphisms in 1694 breast cancer case subjects (92% with two primary cancers or at least two affected first-degree relatives) and 2365 control subjects, with validation in three independent series totaling 11,880 case subjects and 12,487 control subjects. Odds ratios (ORs) and associated 95% confidence intervals (CIs) in each stage and all stages combined were calculated using unconditional logistic regression. Heterogeneity was evaluated with Cochran Q and I(2) statistics. All statistical tests were two-sided.
RESULTS: We identified a novel risk locus for breast cancer at 9q31.2 (rs865686: OR = 0.89, 95% CI = 0.85 to 0.92, P = 1.75 × 10(-10)). This single-nucleotide polymorphism maps to a gene desert, the nearest genes being Kruppel-like factor 4 (KLF4, 636 kb centromeric), RAD23 homolog B (RAD23B, 794 kb centromeric), and actin-like 7A (ACTL7A, 736 kb telomeric). We also identified two variants (rs3734805 and rs9383938) mapping to 6q25.1 estrogen receptor 1 (ESR1), which were associated with breast cancer in subjects of northern European ancestry (rs3734805: OR = 1.19, 95% CI = 1.11 to 1.27, P = 1.35 × 10(-7); rs9383938: OR = 1.18, 95% CI = 1.11 to 1.26, P = 1.41 × 10(-7)). A variant mapping to 10q26.13, approximately 300 kb telomeric to the established risk locus within the second intron of FGFR2, was also associated with breast cancer risk, although not at genome-wide statistical significance (rs10510102: OR = 1.12, 95% CI = 1.07 to 1.17, P = 1.58 × 10(-6)).
CONCLUSIONS: These findings provide further evidence on the role of genetic variation in the etiology of breast cancer. Fine mapping will be needed to identify causal variants and to determine their functional effects.

Butkiewicz D, Rusin M, Sikora B, et al.
An association between DNA repair gene polymorphisms and survival in patients with resected non-small cell lung cancer.
Mol Biol Rep. 2011; 38(8):5231-41 [PubMed] Related Publications
DNA repair genetic polymorphisms have been studied extensively in relation to lung cancer susceptibility, but much less is known about their role in clinical outcome modulation. In this report, we examined effect of the XPA -4G>A, XPD Asp312Asn, Leu751Gln, hHR23B Ala249Val, XPG Asp1104His, XRCC1 Arg399Gln, XRCC2 -4234G>C and XRCC3 Thr241Met polymorphisms on overall survival in 162 patients with resected non-small cell lung cancer (NSCLC). The XRCC3 Met/Met genotype was significantly associated with increased risk of death among all patients and men in uni- and multivariate analyses. The risk was higher for adenocarcinoma patients possessing the XRCC3 Met/Met or XRCC1 Gln/Gln genotypes, although their frequency was small. The XRCC1 399Gln allele was also associated with poor prognosis in stage II-IIIA and among older individuals. Men homozygous for the XPD 312 Asn/Asn had significantly better survival with the risk of death being at borderline significance in uni- and multivariate models. Younger cases and ever smokers smoking less than median pack-years showed significantly increased risk of death associated with the XPA -4A allele. A presence of one or two XRCC2 -4234C alleles had a protective effect in males and ever smokers with lower cumulative smoking dose, although the CC genotype was rarely observed. When number of combined risk alleles was considered, we found that carriers of >4 adverse alleles were at significantly increased risk of death in uni- and multivariate models. Therefore, our results indicate that selected genetic polymorphisms in DNA repair genes may influence overall survival in resected NSCLC.

Guillem VM, Cervantes F, Martínez J, et al.
XPC genetic polymorphisms correlate with the response to imatinib treatment in patients with chronic phase chronic myeloid leukemia.
Am J Hematol. 2010; 85(7):482-6 [PubMed] Related Publications
Chronic myeloid leukemia (CML) is driven by the BCR-ABL protein, which promotes the proliferation and viability of the leukemic cells. Moreover, BCR-ABL induces genomic instability that can contribute to the emergence of resistant clones to the ABL kinase inhibitors. It is currently unknown whether the inherited individual capability to repair DNA damage could affect the treatment results. To address this, a comprehensive analysis of single nucleotide polymorphisms (SNPs) on the nucleotide excision repair (NER) genes (ERCC2-ERCC8, RPA1-RPA3, LIG1, RAD23B, XPA, XPC) was performed in 92 chronic phase CML patients treated with imatinib upfront. ERCC5 and XPC SNPs correlated with the response to imatinib. Haplotype analysis of XPC showed that the wild-type haplotype (499C-939A) was associated with a better response to imatinib. Moreover, the 5-year failure free survival for CA carriers was significantly better than that of the non-CA carriers (98% vs. 73%; P = 0.02). In the multivariate logistic model with genetic data and clinical covariates, the hemoglobin (Hb) level and the XPC haplotype were independently associated with the treatment response, with patients having a Hb < or =11 g/dl (Odds ratio [OR] = 5.0, 95% confidence interval [CI] = 1.5-16.1) or a non-CA XPC haplotype (OR = 4.1, 95% CI = 1.6-10.6) being at higher risk of suboptimal response/treatment failure. Our findings suggest that genetic polymorphisms in the NER pathway may influence the results to imatinib treatment in CML.

Minagawa K, Katayama Y, Nishikawa S, et al.
Inhibition of G(1) to S phase progression by a novel zinc finger protein P58(TFL) at P-bodies.
Mol Cancer Res. 2009; 7(6):880-9 [PubMed] Related Publications
We recently reported the translocation of the immunoglobulin (Ig) light chain kappa locus gene with a possible tumor suppressor gene, TFL, in transformed follicular lymphoma. However, the functional significance in cell transformation remains to be elucidated. Here, we first identified two gene products, P58(TFL) and P36(TFL), derived by alternative splicing. The expression was prominent in normal human lymphocytes but defective in some leukemia/lymphoma cell lines. Overexpression of either protein in a mouse pro-B cell line, Ba/F3, and a human leukemia cell line, Jurkat, inhibited G(1) to S phase progression through suppression of retinoblastoma protein (Rb) phosphorylation. The dominant gene product, P58(TFL), colocalized with mRNA-processing body markers, eukaryotic translation initiation factor 2C and DCP1 decapping-enzyme homolog A, but not with a stress granule maker, T-cell intracellular antigen 1, in the cytoplasm. Taken together with the unique CCCH-type zinc finger motif, the present study suggests that P58(TFL) could play an important role in the regulation of cell growth through posttranscriptional modification of cell cycle regulators, at least partially, upstream of Rb.

Abbasi R, Ramroth H, Becher H, et al.
Laryngeal cancer risk associated with smoking and alcohol consumption is modified by genetic polymorphisms in ERCC5, ERCC6 and RAD23B but not by polymorphisms in five other nucleotide excision repair genes.
Int J Cancer. 2009; 125(6):1431-9 [PubMed] Related Publications
Laryngeal cancer is known to be associated with smoking and high alcohol consumption. Nucleotide excision repair (NER) plays a key role in repairing DNA damage induced by these exposures and might affect laryngeal cancer susceptibility. In a population-based case-control study including 248 cases and 647 controls, the association of laryngeal cancer with 14 single nucleotide polymorphisms (SNPs) in 8 NER genes (XPC, XPA, ERCC1, ERCC2, ERCC4, ERCC5, ERCC6 and RAD23B) was analyzed with respect to smoking and alcohol exposure. For genotyping, sequence specific hybridization probes were used. Data were evaluated by conditional logistic regression analysis, stratified for age and gender, and adjusted for smoking, alcohol consumption and education. Pro-carriers of ERCC6 Arg1230Pro showed a decreased risk for laryngeal cancer (OR = 0.53, 95% CI 0.34-0.85), strongest in heavy smokers and high alcohol consumers. ERCC5 Asp1104His was associated with risk in heavy smokers (OR = 1.70, 95% CI 1.1-2.5). Val-carriers of RAD23B Ala249Val had an increased cancer risk in heavy smokers (OR = 1.6, 95% CI 1.1-2.5) and high alcohol consumers (OR = 2.0, 95% CI 1.1-3.4). The combined effect of smoking and alcohol intake affected risk, at high exposure level, for ERCC6 1230Pro carriers (OR = 0.47, 95% CI 0.22-0.98) and RAD23B 249Val carriers (OR = 2.6, 95% CI 1.3-4.9). When tested for gene-gene interaction, presence of 3 risk alleles in the XPC-RAD23B complex increased the risk 2.1-fold. SNPs in the other genes did not show a significant association with laryngeal cancer risk. We conclude that common genetic variations in NER genes can significantly modify laryngeal cancer risk.

Pan J, Lin J, Izzo JG, et al.
Genetic susceptibility to esophageal cancer: the role of the nucleotide excision repair pathway.
Carcinogenesis. 2009; 30(5):785-92 [PubMed] Free Access to Full Article Related Publications
In this case-control study with 387 White esophageal patients and 462 White controls matched to cases by age and sex, we evaluated the associations between 13 potential functional polymorphisms in eight major nucleotide excision repair (NER) genes and esophageal cancer risk. In individual single nucleotide polymorphism analysis, after adjustment for multiple comparisons, the heterozygous GT genotype of the ERCC1 3' untranslated region (UTR) was associated with an increased risk, whereas the homozygous variant genotype TT was associated with 60% reduction in risk with an odds ratio (OR) of 0.40 (95% confidence interval [CI] = 0.19-0.86). The heterozygous AG genotype of XPA 5' UTR was at 2.11-fold increased risk (95% CI = 1.33-3.35) and the risk reached 3.10-fold (95% CI = 1.94-4.95) for the homozygous variant GG genotype. These associations were also significant when restricted the analyses in patients with esophageal adenocarcinoma. Further, the CT genotype of the RAD23B Ala249Val was associated with increased esophageal cancer risk (OR = 1.44; 95% CI = 1.05-1.97), whereas the poly-AT-/+ genotype of the XPC intron 9 conferred a decreased risk (OR = 0.71, 95% CI = 0.51-0.97). In joint analysis, individuals carrying 1 (OR = 2.64, 95% CI = 1.57-4.52) and > or = 2 (OR = 2.74, 95% CI = 1.58-4.75) unfavorable genotypes exhibited significantly increased risk for esophageal cancer risk with significant dose-response trend (P for trend = 0.006). The pathway-based risk was more evident in ever smokers, overweight/obese individuals, men and ever drinkers. Our results support the hypothesis that increasing numbers of unfavorable genotypes in the NER predispose susceptible individuals to increased risk of esophageal cancer. These findings warrant further replications in different populations.

Crosby ME, Kulshreshtha R, Ivan M, Glazer PM
MicroRNA regulation of DNA repair gene expression in hypoxic stress.
Cancer Res. 2009; 69(3):1221-9 [PubMed] Free Access to Full Article Related Publications
Genetic instability is a hallmark of cancer; the hypoxic tumor microenvironment has been implicated as a cause of this phenomenon. MicroRNAs (miR) are small nonprotein coding RNAs that can regulate various cellular pathways. We report here that two miRs, miR-210 and miR-373, are up-regulated in a hypoxia-inducible factor-1alpha-dependent manner in hypoxic cells. Bioinformatics analyses suggested that these miRs could regulate factors implicated in DNA repair pathways. Forced expression of miR-210 was found to suppress the levels of RAD52, which is a key factor in homology-dependent repair (HDR); the forced expression of miR-373 led to a reduction in the nucleotide excision repair (NER) protein, RAD23B, as well as in RAD52. Consistent with these results, both RAD52 and RAD23B were found to be down-regulated in hypoxia, but in both cases, the hypoxia-induced down-regulation could be partially reversed by antisense inhibition of miR-210 and miR-373. Importantly, luciferase reporter assays indicated that miR-210 is capable of interacting with the 3' untranslated region (UTR) of RAD52 and that miR-373 can act on the 3' UTR of RAD23B. These results indicate that hypoxia-inducible miR-210 and miR-373 play roles in modulating the expression levels of key proteins involved in the HDR and NER pathways, providing new mechanistic insight into the effect of hypoxia on DNA repair and genetic instability in cancer.

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