PATZ1

Gene Summary

Gene:PATZ1; POZ/BTB and AT hook containing zinc finger 1
Aliases: ZSG, MAZR, PATZ, RIAZ, ZBTB19, ZNF278, dJ400N23
Location:22q12.2
Summary:The protein encoded by this gene contains an A-T hook DNA binding motif which usually binds to other DNA binding structures to play an important role in chromatin modeling and transcription regulation. Its Poz domain is thought to function as a site for protein-protein interaction and is required for transcriptional repression, and the zinc-fingers comprise the DNA binding domain. Since the encoded protein has typical features of a transcription factor, it is postulated to be a repressor of gene expression. In small round cell sarcoma, this gene is fused to EWS by a small inversion of 22q, then the hybrid is thought to be translocated (t(1;22)(p36.1;q12). The rearrangement of chromosome 22 involves intron 8 of EWS and exon 1 of this gene creating a chimeric sequence containing the transactivation domain of EWS fused to zinc finger domain of this protein. This is a distinct example of an intra-chromosomal rearrangement of chromosome 22. Four alternatively spliced transcript variants are described for this gene. [provided by RefSeq, Jul 2008]
Databases:VEGA, OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:POZ-, AT hook-, and zinc finger-containing protein 1
Source:NCBIAccessed: 13 March, 2017

Cancer Overview

Research Indicators

Publications Per Year (1992-2017)
Graph generated 13 March 2017 using data from PubMed using criteria.

Literature Analysis

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Tag cloud generated 13 March, 2017 using data from PubMed, MeSH and CancerIndex

Specific Cancers (6)

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: PATZ1 (cancer-related)

Abdulrahman N, Jaballah M, Poomakkoth N, et al.
Inhibition of p90 ribosomal S6 kinase attenuates cell migration and proliferation of the human lung adenocarcinoma through phospho-GSK-3β and osteopontin.
Mol Cell Biochem. 2016; 418(1-2):21-9 [PubMed] Related Publications
p90 ribosomal S6 kinase (p90RSK) constitutes a family of serine/threonine kinases that have been shown to be involved in cell proliferation of various malignancies via direct or indirect effects on the cell-cycle machinery. We investigated the role of p90RSK in lung adenocarcinomas and whether the inhibition of p90RSK diminishes cancer progression. Moreover, we investigated the involvement of glycogen synthase kinase-3β (GSK-3β) and osteopontin (OPN) in the p90RSK-induced lung adenocarcinoma progression. p90RSK, OPN, and GSK-3β protein expressions were examined in the A549 human lung adenocarcinoma cell line in the presence and absence of BI-D1870 (BID), a p90RSK inhibitor. Gene expression of anti-apoptotic and pro-apoptotic markers namely Bcl2 and Bax, respectively, were studied by reverse transcription polymerase chain reaction. In addition, the A549 lung adenocarcinoma cell line was characterized for cell proliferation using the MTT assay and cell migration using the scratch migration assay. Our study revealed that total RSK1 protein expression is over expressed in the A549 human lung adenocarcinoma cell line, an effect which is significantly reduced upon pretreatment with BID (69.32 ± 12.41 % of control; P < 0.05). The inhibition of p90RSK also showed a significant suppression of cell proliferation (54.3 ± 6.73 % of control; P < 0.01) and cell migration (187.90 ± 16.10 % of control; P < 0.01). Treatment of the A549 cells with BID regressed the expression of Bcl2 mRNA (56.92 ± 6.07 % of control; P < 0.01). BID also regressed protein expression of OPN (79.57 ± 5.32 % of control; P < 0.05) and phospho-GSK-3β (73.04 ± 8.95 % of control; P < 0.05). The p90RSK has an essential role in promoting tumor growth and proliferation in non-small cell lung cancer (NSCLC). BID may serve as an alternative cancer treatment in NSCLC.

Reznik E, Miller ML, Şenbabaoğlu Y, et al.
Mitochondrial DNA copy number variation across human cancers.
Elife. 2016; 5 [PubMed] Free Access to Full Article Related Publications
Mutations, deletions, and changes in copy number of mitochondrial DNA (mtDNA), are observed throughout cancers. Here, we survey mtDNA copy number variation across 22 tumor types profiled by The Cancer Genome Atlas project. We observe a tendency for some cancers, especially of the bladder, breast, and kidney, to be depleted of mtDNA, relative to matched normal tissue. Analysis of genetic context reveals an association between incidence of several somatic alterations, including IDH1 mutations in gliomas, and mtDNA content. In some but not all cancer types, mtDNA content is correlated with the expression of respiratory genes, and anti-correlated to the expression of immune response and cell-cycle genes. In tandem with immunohistochemical evidence, we find that some tumors may compensate for mtDNA depletion to sustain levels of respiratory proteins. Our results highlight the extent of mtDNA copy number variation in tumors and point to related therapeutic opportunities.

Morris LG, Riaz N, Desrichard A, et al.
Pan-cancer analysis of intratumor heterogeneity as a prognostic determinant of survival.
Oncotarget. 2016; 7(9):10051-63 [PubMed] Free Access to Full Article Related Publications
As tumors accumulate genetic alterations, an evolutionary process occurs in which genetically distinct subclonal populations of cells co-exist, resulting in intratumor genetic heterogeneity (ITH). The clinical implications of ITH remain poorly defined. Data are limited with respect to whether ITH is an independent determinant of patient survival outcomes, across different cancer types. Here, we report the results of a pan-cancer analysis of over 3300 tumors, showing a varied landscape of ITH across 9 cancer types. While some gene mutations are subclonal, the majority of driver gene mutations are clonal events, present in nearly all cancer cells. Strikingly, high levels of ITH are associated with poorer survival across diverse types of cancer. The adverse impact of high ITH is independent of other clinical, pathologic and molecular factors. High ITH tends to be associated with lower levels of tumor-infiltrating immune cells, but this association is not able to explain the observed survival differences. Together, these data show that ITH is a prognostic marker in multiple cancers. These results illuminate the natural history of cancer evolution, indicating that tumor heterogeneity represents a significant obstacle to cancer control.

Ward AK, Mellor P, Smith SE, et al.
Epigenetic silencing of CREB3L1 by DNA methylation is associated with high-grade metastatic breast cancers with poor prognosis and is prevalent in triple negative breast cancers.
Breast Cancer Res. 2016; 18(1):12 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: CREB3L1 (cAMP-responsive element-binding protein 3-like protein 1), a member of the unfolded protein response, has recently been identified as a metastasis suppressor in both breast and bladder cancer.
METHODS: Quantitative real time PCR (qPCR) and immunoblotting were used to determine the impact of histone deacetylation and DNA methylation inhibitors on CREB3L1 expression in breast cancer cell lines. Breast cancer cell lines and tumor samples were analyzed similarly, and CREB3L1 gene methylation was determined using sodium bisulfite conversion and DNA sequencing. Immunohistochemistry was used to determine nuclear versus cytoplasmic CREB3L1 protein. Large breast cancer database analyses were carried out to examine relationships between CREB3L1 gene methylation and mRNA expression in addition to CREB3L1 mRNA expression and prognosis.
RESULTS: This study demonstrates that the low CREB3L1 expression previously seen in highly metastatic breast cancer cell lines is caused in part by epigenetic silencing. Treatment of several highly metastatic breast cancer cell lines that had low CREB3L1 expression with DNA methyltransferase and histone deacetylase inhibitors induced expression of CREB3L1, both mRNA and protein. In human breast tumors, CREB3L1 mRNA expression was upregulated in low and medium-grade tumors, most frequently of the luminal and HER2 amplified subtypes. In contrast, CREB3L1 expression was repressed in high-grade tumors, and its loss was most frequently associated with triple negative breast cancers (TNBCs). Importantly, bioinformatics analyses of tumor databases support these findings, with methylation of the CREB3L1 gene associated with TNBCs, and strongly negatively correlated with CREB3L1 mRNA expression. Decreased CREB3L1 mRNA expression was associated with increased tumor grade and reduced progression-free survival. An immunohistochemistry analysis revealed that low-grade breast tumors frequently had nuclear CREB3L1 protein, in contrast to the high-grade breast tumors in which CREB3L1 was cytoplasmic, suggesting that differential localization may also regulate CREB3L1 effectiveness in metastasis suppression.
CONCLUSIONS: Our data further strengthens the role for CREB3L1 as a metastasis suppressor in breast cancer and demonstrates that epigenetic silencing is a major regulator of the loss of CREB3L1 expression. We also highlight that CREB3L1 expression is frequently altered in many cancer types suggesting that it could have a broader role in cancer progression and metastasis.

Campa MJ, Moody MA, Zhang R, et al.
Interrogation of individual intratumoral B lymphocytes from lung cancer patients for molecular target discovery.
Cancer Immunol Immunother. 2016; 65(2):171-80 [PubMed] Related Publications
Intratumoral B lymphocytes are an integral part of the lung tumor microenvironment. Interrogation of the antibodies they express may improve our understanding of the host response to cancer and could be useful in elucidating novel molecular targets. We used two strategies to explore the repertoire of intratumoral B cell antibodies. First, we cloned VH and VL genes from single intratumoral B lymphocytes isolated from one lung tumor, expressed the genes as recombinant mAbs, and used the mAbs to identify the cognate tumor antigens. The Igs derived from intratumoral B cells demonstrated class switching, with a mean VH mutation frequency of 4%. Although there was no evidence for clonal expansion, these data are consistent with antigen-driven somatic hypermutation. Individual recombinant antibodies were polyreactive, although one clone demonstrated preferential immunoreactivity with tropomyosin 4 (TPM4). We found that higher levels of TPM4 antibodies were more common in cancer patients, but measurement of TPM4 antibody levels was not a sensitive test for detecting cancer. Second, in an effort to focus our recombinant antibody expression efforts on those B cells that displayed evidence of clonal expansion driven by antigen stimulation, we performed deep sequencing of the Ig genes of B cells collected from seven different tumors. Deep sequencing demonstrated somatic hypermutation but no dominant clones. These strategies may be useful for the study of B cell antibody expression, although identification of a dominant clone and unique therapeutic targets may require extensive investigation.

Goh G, Walradt T, Markarov V, et al.
Mutational landscape of MCPyV-positive and MCPyV-negative Merkel cell carcinomas with implications for immunotherapy.
Oncotarget. 2016; 7(3):3403-15 [PubMed] Free Access to Full Article Related Publications
Merkel cell carcinoma (MCC) is a rare but highly aggressive cutaneous neuroendocrine carcinoma, associated with the Merkel cell polyomavirus (MCPyV) in 80% of cases. To define the genetic basis of MCCs, we performed exome sequencing of 49 MCCs. We show that MCPyV-negative MCCs have a high mutation burden (median of 1121 somatic single nucleotide variants (SSNVs) per-exome with frequent mutations in RB1 and TP53 and additional damaging mutations in genes in the chromatin modification (ASXL1, MLL2, and MLL3), JNK (MAP3K1 and TRAF7), and DNA-damage pathways (ATM, MSH2, and BRCA1). In contrast, MCPyV-positive MCCs harbor few SSNVs (median of 12.5 SSNVs/tumor) with none in the genes listed above. In both subgroups, there are rare cancer-promoting mutations predicted to activate the PI3K pathway (HRAS, KRAS, PIK3CA, PTEN, and TSC1) and to inactivate the Notch pathway (Notch1 and Notch2). TP53 mutations appear to be clinically relevant in virus-negative MCCs as 37% of these tumors harbor potentially targetable gain-of-function mutations in TP53 at p.R248 and p.P278. Moreover, TP53 mutational status predicts death in early stage MCC (5-year survival in TP53 mutant vs wild-type stage I and II MCCs is 20% vs. 92%, respectively; P = 0.0036). Lastly, we identified the tumor neoantigens in MCPyV-negative and MCPyV-positive MCCs. We found that virus-negative MCCs harbor more tumor neoantigens than melanomas or non-small cell lung cancers (median of 173, 65, and 111 neoantigens/sample, respectively), two cancers for which immune checkpoint blockade can produce durable clinical responses. Collectively, these data support the use of immunotherapies for virus-negative MCCs.

Miana GA, Riaz M, Shahzad-ul-Hussan S, et al.
Prostratin: An Overview.
Mini Rev Med Chem. 2015; 15(13):1122-30 [PubMed] Related Publications
Terpenoid class of molecules possesses a diverse therapeutic properties and potentials owing to their specific structural features. Prostratin and its derivatives are exemplified in this context to exhibit a variety of biological activities. In this review we discuss in detail the role of prostratin as potential therapeutic and underlying molecular mechanisms by which it accomplishes these activities. Prostratin [13-O-acetyl-12-deoxyphorbol] is a phorbol ester that was first isolated from Strathmore weed Pimelea prostrate, a small endemic New Zealand shrub, and characterized by Hecker in 1976. Structurally, prostratin contains four rings designated as A, B, C and D. Ring A is trans linked to the 7-membered ring B while Ring C is a 6 membered and is cis linked to the cyclopentane ring D. Chemical synthesis of this compound initiated with acidic hydrolysis of phorbol, a tigliane diterpene isolated from croton oil. Prostratin-containing extracts have been used by the Samoan healers to treat individuals with certain medical conditions such as jaundice. Importantly, these treatments are not associated with any significant side effect. Prostratin inhibits HIV-1 infections by down regulating HIV-1 cellular receptors through the activation of protein kinase C (PKC) pathway and reduces the HIV-1 latency. Unlike other phorbol esters that induce carcinogenesis by activating PKC, prostratin does not induce tumors rather has shown tumor suppressing activity. Its ability to induce lytic gene expression supports a role for phorbol-ester regulated signaling pathways in Kaposi's sarcoma associated herpes-virus reactivation.

Chiappetta G, Valentino T, Vitiello M, et al.
PATZ1 acts as a tumor suppressor in thyroid cancer via targeting p53-dependent genes involved in EMT and cell migration.
Oncotarget. 2015; 6(7):5310-23 [PubMed] Free Access to Full Article Related Publications
PATZ1, a POZ-Zinc finger protein, is emerging as an important regulator of development and cancer, but its cancer-related function as oncogene or tumor-suppressor is still debated. Here, we investigated its possible role in thyroid carcinogenesis. We demonstrated PATZ1 is down-regulated in thyroid carcinomas compared to normal thyroid tissues, with an inverse correlation to the degree of cell differentiation. In fact, PATZ1 expression was significantly further down-regulated in poorly differentiated and anaplastic thyroid cancers compared to the papillary histotype, and it resulted increasingly delocalized from the nucleus to the cytoplasm proceeding from differentiated to undifferentiated thyroid carcinomas. Restoration of PATZ1 expression in three thyroid cancer-derived cell lines, all characterized by fully dedifferentiated cells, significantly inhibited their malignant behaviors, including in vitro proliferation, anchorage-independent growth, migration and invasion, as well as in vivo tumor growth. Consistent with recent studies showing a role for PATZ1 in the p53 pathway, we showed that ectopic expression of PATZ1 in thyroid cancer cells activates p53-dependent pathways opposing epithelial-mesenchymal transition and cell migration to prevent invasiveness. These results provide insights into a potential tumor-suppressor role of PATZ1 in thyroid cancer progression, and thus may have potential clinical relevance for the prognosis and therapy of thyroid cancer.

Naderi A
Coagulation factor VII is regulated by androgen receptor in breast cancer.
Exp Cell Res. 2015; 331(1):239-50 [PubMed] Free Access to Full Article Related Publications
Androgen receptor (AR) is widely expressed in breast cancer; however, there is limited information on the key molecular functions and gene targets of AR in this disease. In this study, gene expression data from a cohort of 52 breast cancer cell lines was analyzed to identify a network of AR co-expressed genes. A total of 300 genes, which were significantly enriched for cell cycle and metabolic functions, showed absolute correlation coefficients (|CC|) of more than 0.5 with AR expression across the dataset. In this network, a subset of 35 "AR-signature" genes were highly co-expressed with AR (|CC|>0.6) that included transcriptional regulators PATZ1, NFATC4, and SPDEF. Furthermore, gene encoding coagulation factor VII (F7) demonstrated the closest expression pattern with AR (CC=0.716) in the dataset and factor VII protein expression was significantly associated to that of AR in a cohort of 209 breast tumors. Moreover, functional studies demonstrated that AR activation results in the induction of factor VII expression at both transcript and protein levels and AR directly binds to a proximal region of F7 promoter in breast cancer cells. Importantly, AR activation in breast cancer cells induced endogenous factor VII activity to convert factor X to Xa in conjunction with tissue factor. In summary, F7 is a novel AR target gene and AR activation regulates the ectopic expression and activity of factor VII in breast cancer cells. These findings have functional implications in the pathobiology of thromboembolic events and regulation of factor VII/tissue factor signaling in breast cancer.

Riaz W, Zhang L, Horna P, Sokol L
Blastic plasmacytoid dendritic cell neoplasm: update on molecular biology, diagnosis, and therapy.
Cancer Control. 2014; 21(4):279-89 [PubMed] Related Publications
BACKGROUND: Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematological malignancy with an aggressive clinical course. Most patients with BPDCN have skin lesions and simultaneous involvement of the peripheral blood, bone marrow, and lymph nodes.
METHODS: A search of PubMed and Medline was conducted for English-written articles relating to BPDCN, CD4(+)CD56(+) hematodermic neoplasm, and blastic natural killer cell lymphoma. Data regarding diagnosis, prognosis, and treatment were analyzed.
RESULTS: BPDCN is derived from precursor plasmacytoid dendritic cells. The diagnosis of BPDCN is based on the characteristic cytology and immunophenotype of malignant cells coexpressing CD4, CD56, CD123, blood dendritic cell antigens 2 and 4, and CD2AP markers. Multiple chromosomal abnormalities and gene mutations previously reported in patients with myeloid and selected lymphoid neoplasms were identified in approximately 60% of patients with BPDCN. Prospectively controlled studies to guide treatment decisions are lacking. The overall response rate with aggressive acute lymphoblastic leukemia-type induction regimens was as high as 90%, but the durability of response was short. Median survival rates ranged between 12 and 16 months. Patients with relapsed disease may respond to L-asparaginase-containing regimens. Allogeneic hematopoietic stem cell transplantation, particularly when performed during the first remission, may produce durable remissions in selected adults.
CONCLUSIONS: BPDCN is a rare aggressive disease that typically affects elderly patients. The most commonly affected nonhematopoietic organ is the skin. Although BPDCN is initially sensitive to conventional chemotherapy regimens, this response is relatively short and long-term prognosis is poor. In the near future, novel targeted therapies may improve outcomes for patients with BPDCN.

Vijay Avin BR, Prabhu T, Ramesh CK, et al.
New role of lupeol in reticence of angiogenesis, the cellular parameter of neoplastic progression in tumorigenesis models through altered gene expression.
Biochem Biophys Res Commun. 2014; 448(2):139-44 [PubMed] Related Publications
There is a major unmet medical need for effective and well tolerated treatment options for cancer. The search now seeks to identify active biomolecules with multiple targets. Lupeol, an important dietary triterpenoid known as anticarcinogen by inducing apoptosis. But it is still more to reveal the potency of lupeol in the inhibition of neovascularization in cancer context. The study aimed to explore the efficacy of the lupeol in targeting angiogenesis. In this study, the inhibition of neovessel formation was assessed by preliminary antiangiogenesis assays like chorio allontoic membrane (CAM) and rat corneal micro pocket models. Further, validated for the micro vessel density (MVD) in histological sections of peritoneum, solid tumor and xenograft tumor by immunostaining with anti CD31 antibody. Antitumor potency was verified in ascites carcinoma, solid lymphoma and human nueroblastoma xenograft in CAM. Altered angiogenic gene expression by RT-PCR, ELISA and gelatin zymography. Lupeol significantly inhibits the neovessel formation in CAM and in the rat cornea. The similar effect was ascertained in mice and human xenograft tumor models with the regressed growth. Eventually reflecting on the differential transcription of angiogenic genes like MMP-2 & 9, HIF-1α, VEGFa and Flt-1 was noteworthy. It is now evident from our studies that, a new avenue of dietary triterpenoid lupeol by targeting angiogenesis, potentially inferring the multimode action in cancer prevention.

Riaz M, van Jaarsveld MT, Hollestelle A, et al.
miRNA expression profiling of 51 human breast cancer cell lines reveals subtype and driver mutation-specific miRNAs.
Breast Cancer Res. 2013; 15(2):R33 [PubMed] Free Access to Full Article Related Publications
INTRODUCTION: Breast cancer is a genetically and phenotypically complex disease. To understand the role of miRNAs in this molecular complexity, we performed miRNA expression analysis in a cohort of molecularly well-characterized human breast cancer cell lines to identify miRNAs associated with the most common molecular subtypes and the most frequent genetic aberrations.
METHODS: Using a microarray carrying LNA™ modified oligonucleotide capture probes), expression levels of 725 human miRNAs were measured in 51 breast cancer cell lines. Differential miRNA expression was explored by unsupervised cluster analysis and was then associated with the molecular subtypes and genetic aberrations commonly present in breast cancer.
RESULTS: Unsupervised cluster analysis using the most variably expressed miRNAs divided the 51 breast cancer cell lines into a major and a minor cluster predominantly mirroring the luminal and basal intrinsic subdivision of breast cancer cell lines. One hundred and thirteen miRNAs were differentially expressed between these two main clusters. Forty miRNAs were differentially expressed between basal-like and normal-like/claudin-low cell lines. Within the luminal-group, 39 miRNAs were associated with ERBB2 overexpression and 24 with E-cadherin gene mutations, which are frequent in this subtype of breast cancer cell lines. In contrast, 31 miRNAs were associated with E-cadherin promoter hypermethylation, which, contrary to E-cadherin mutation, is exclusively observed in breast cancer cell lines that are not of luminal origin. Thirty miRNAs were associated with p16INK4 status while only a few miRNAs were associated with BRCA1, PIK3CA/PTEN and TP53 mutation status. Twelve miRNAs were associated with DNA copy number variation of the respective locus.
CONCLUSION: Luminal-basal and epithelial-mesenchymal associated miRNAs determine the subdivision of miRNA transcriptome of breast cancer cell lines. Specific sets of miRNAs were associated with ERBB2 overexpression, p16INK4a or E-cadherin mutation or E-cadherin methylation status, which implies that these miRNAs may contribute to the driver role of these genetic aberrations. Additionally, miRNAs, which are located in a genomic region showing recurrent genetic aberrations, may themselves play a driver role in breast carcinogenesis or contribute to a driver gene in their vicinity. In short, our study provides detailed molecular miRNA portraits of breast cancer cell lines, which can be exploited for functional studies of clinically important miRNAs.

Wu C, Han L, Riaz H, et al.
The chemopreventive effect of β-cryptoxanthin from mandarin on human stomach cells (BGC-823).
Food Chem. 2013; 136(3-4):1122-9 [PubMed] Related Publications
β-Cryptoxanthin, a provitaminic carotenoid, present in many fruits and vegetables, has been associated with decreased risk of chronic diseases, including cancer. The influence of β-cryptoxanthin derived from mandarin on the proliferation of the stomach tumor cell line BGC-823 was tested using MTT and cell count assay at 72 h and dose-response (from 0.01 to 20 μM). β-Cryptoxanthin suppressed the cell migration by the scratch assay. Furthermore, β-cryptoxanthin induced an accumulation of cells in the G1/G0 phase of the cell cycle (as detected by flow cytometry), which was in accordance with an increased expression of p21 and down regulations of cyclin D1 and cyclin E, detected by Western blot analysis, and β-cryptoxanthin increased the mRNA levels of retinoic acid receptor β (RARβ) with the treatment at 10 μM for 24 h. Collectively, the above findings suggest that β-cryptoxanthin could be therapeutic in the treatment of stomach cancer cell in vitro.

Riaz M, Sieuwerts AM, Look MP, et al.
High TWIST1 mRNA expression is associated with poor prognosis in lymph node-negative and estrogen receptor-positive human breast cancer and is co-expressed with stromal as well as ECM related genes.
Breast Cancer Res. 2012; 14(5):R123 [PubMed] Free Access to Full Article Related Publications
INTRODUCTION: The TWIST homolog 1 (TWIST1) is a transcription factor that induces epithelial to mesenchymal transition (EMT), a key process in metastasis. The purpose of this study was to investigate whether TWIST1 expression predicts disease progression in a large breast cancer cohort with long-term clinical follow-up, and to reveal the biology related to TWIST1 mediated disease progression.
METHODS: TWIST1 mRNA expression level was analyzed by quantitative real-time reverse polymerase chain reaction (RT-PCR) in 1,427 primary breast cancers. In uni- and multivariate analysis using Cox regression, TWIST1 mRNA expression level was associated with metastasis-free survival (MFS), disease-free survival (DFS) and overall survival (OS). Separate analyses in lymph node-negative patients (LNN, n = 778) who did not receive adjuvant systemic therapy, before and after stratification into estrogen receptor (ER)-positive (n = 552) and ER-negative (n = 226) disease, were also performed. The association of TWIST1 mRNA with survival endpoints was assessed using Kaplan-Meier analysis. Using gene expression arrays, genes showing a significant Spearman rank correlation with TWIST1 were used to identify overrepresented Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG)-annotated biological pathways.
RESULTS: Increased mRNA expression level of TWIST1 analyzed as a continuous variable in both uni- and multivariate analysis was associated with shorter MFS in all patients (hazard ratio (HR): 1.17, 95% confidence interval, (95% CI):1.09 to 1.26; and HR: 1.17, 95% CI: 1.08 to 1.26; respectively), in LNN patients (HR: 1.22, 95% CI: 1.09 to 1.36; and HR: 1.21, 95% CI: 1.07 to 1.36; respectively) and in the ER-positive subgroup of LNN patients (HR: 1.34, 95% CI: 1.17 to 1.53; and HR: 1.32, 95% CI: 1.14 to 1.53; respectively). Similarly, high TWIST1 expression was associated with shorter DFS and OS in all patients and in the LNN/ER-positive subgroup. In contrast, no association of TWIST1 mRNA expression with MFS, DFS or OS was observed in ER-negative patients. Genes highly correlated with TWIST1 were significantly enriched for cell adhesion and ECM-related signaling pathways. Furthermore, TWIST1 mRNA was highly expressed in tumor stroma and positively related to tumor stromal content (P <0.001).
CONCLUSIONS: TWIST1 mRNA expression is an independent prognostic factor for poor prognosis in LNN/ER-positive breast cancer. The biological associations suggest an involvement of the tumor microenvironment in TWIST1's adverse role in breast cancer.

Pero R, Palmieri D, Angrisano T, et al.
POZ-, AT-hook-, and zinc finger-containing protein (PATZ) interacts with human oncogene B cell lymphoma 6 (BCL6) and is required for its negative autoregulation.
J Biol Chem. 2012; 287(22):18308-17 [PubMed] Free Access to Full Article Related Publications
The PATZ1 gene encoding a POZ/AT-hook/Kruppel zinc finger (PATZ) transcription factor, is considered a cancer-related gene because of its loss or misexpression in human neoplasias. As for other POZ/domain and Kruppel zinc finger (POK) family members, the transcriptional activity of PATZ is due to the POZ-mediated oligomer formation, suggesting that it might be not a typical transactivator but an architectural transcription factor, thus functioning either as activator or as repressor depending on the presence of proteins able to interact with it. Therefore, to better elucidate PATZ function, we searched for its molecular partners. By yeast two-hybrid screenings, we found a specific interaction between PATZ and BCL6, a human oncogene that plays a key role in germinal center (GC) derived neoplasias. We demonstrate that PATZ and BCL6 interact in germinal center-derived B lymphoma cells, through the POZ domain of PATZ. Moreover, we show that PATZ is able to bind the BCL6 regulatory region, where BCL6 itself acts as a negative regulator, and to contribute to negatively modulate its activity. Consistently, disruption of one or both Patz1 alleles in mice causes focal expansion of thymus B cells, in which BCL6 is up-regulated. This phenotype was almost completely rescued by crossing Patz1(+/-) with Bcl6(+/-) mice, indicating a key role for Bcl6 expression in its development. Finally, a significant number of Patz1 knock-out mice (both heterozygous and homozygous) also develop BCL6-expressing lymphomas. Therefore, the disruption of one or both Patz1 alleles may favor lymphomagenesis by activating the BCL6 pathway.

Sankar S, Lessnick SL
Promiscuous partnerships in Ewing's sarcoma.
Cancer Genet. 2011; 204(7):351-65 [PubMed] Free Access to Full Article Related Publications
Ewing's sarcoma is a highly aggressive bone and soft tissue tumor of children and young adults. At the molecular genetic level Ewing's sarcoma is characterized by a balanced reciprocal translocation, t(11;22)(q24;q12), which encodes an oncogenic fusion protein and transcription factor EWS/FLI. This tumor-specific chimeric fusion retains the amino terminus of EWS, a member of the TET (TLS/EWS/TAF15) family of RNA-binding proteins, and the carboxy terminus of FLI, a member of the ETS family of transcription factors. In addition to EWS/FLI, variant translocation fusions belonging to the TET/ETS family have been identified in Ewing's sarcoma. These studies solidified the importance of TET/ETS fusions in the pathogenesis of Ewing's sarcoma and have since been used as diagnostic markers for the disease. EWS fusions with non-ETS transcription factor family members have been described in sarcomas that are clearly distinct from Ewing's sarcoma. However, in recent years there have been reports of rare fusions in "Ewing's-like tumors" that harbor the amino-terminus of EWS fused to the carboxy-terminal DNA or chromatin-interacting domains contributed by non-ETS proteins. This review aims to summarize the growing list of fusion oncogenes that characterize Ewing's sarcoma and Ewing's-like tumors and highlights important questions that need to be answered to further support the existing concept that Ewing's sarcoma is strictly a "TET/ETS" fusion-driven malignancy. Understanding the molecular mechanisms of action of the various different fusion oncogenes will provide better insights into the biology underlying this rare but important solid tumor.

Asim M, Hafeez BB, Siddiqui IA, et al.
Ligand-dependent corepressor acts as a novel androgen receptor corepressor, inhibits prostate cancer growth, and is functionally inactivated by the Src protein kinase.
J Biol Chem. 2011; 286(43):37108-17 [PubMed] Free Access to Full Article Related Publications
The activated androgen receptor (AR) promotes prostate cancer (PCa) growth. AR antagonists repress the AR by recruitment of corepressors. Not much is known about the inactivation of AR by corepressors in the presence of agonists (androgens). Here we show that the corepressor LCoR acts as an androgen-dependent corepressor that represses human PCa growth in vivo. In line with this, progressive decrease of ligand-dependent corepressor expression was observed in the PCa TRAMP mouse model with increasing age. LCoR interacts with AR and is recruited to chromatin in an androgen-induced manner. Unexpectedly, the LXXLL motif of LCoR is dispensable for interaction with the AR. Rather, the data indicate that LCoR interacts with the AR DNA binding domain on DNA. Interestingly, the interaction of LCoR with AR is inhibited by signaling pathways that are associated with androgen-independent PCa. Here we also show that the Src kinase inactivates the corepressive function of LCoR. Interfering with endogenous Src function by a dominant negative Src mutant, the growth inhibitory activity of LCoR is enhanced in vivo in a xenograft mouse model system. Thus, our studies indicate a role of LCoR as an AR corepressor and a tumor suppressor. Further, the decreased expression or inactivation of LCoR is as an important step toward PCa carcinogenesis in vivo.

Riaz M, Berns EM, Sieuwerts AM, et al.
Correlation of breast cancer susceptibility loci with patient characteristics, metastasis-free survival, and mRNA expression of the nearest genes.
Breast Cancer Res Treat. 2012; 133(3):843-51 [PubMed] Related Publications
To understand the biology of low-risk breast cancer alleles, and to investigate whether these loci also contribute to disease progression that was once established, we examined the association of SNPs tagging the low-risk breast cancer loci in or near FGFR2, LSP1, MAP3K1, H19, TOX3, POU5F1P1, MYC, and 2q35, with clinical, pathological characteristics, prognosis, and mRNA expression of the nearest genes. Tumor DNA samples of 2,480 breast cancer patients were available. Out of this cohort, 1,290 patients with lymph-node negative disease who did not receive adjuvant systemic therapy, the SNP status was associated with metastasis-free survival (MFS). In 1,401 patients, the mRNA expression levels of FGFR2, LSP1, MAP3K1, H19, TOX3, POU5F1P1, and MYC were determined and correlated with SNP genotypes. The SNP rs2981582 in FGFR2 was significantly associated with positive ER and PgR status (P < 0.001 and P = 0.003, respectively). No other significant associations with patient or tumor characteristics were observed. Only rs2107425 near H19 was significantly associated with shorter MFS in uni- and multi-variate analysis (HR: 1.53, CI: 1.12-2.08, P = 0.006 and HR: 1.59, CI: 1.16-2.20, P = 0.004, respectively), with the more aggressive minor allele displaying a recessive trait. The minor allele of SNP rs3803662 located near the TOX3 gene was associated with lower mRNA expression of this gene. In conclusion, except for the association of rs13283662 with TOX3 gene expression indicating a tumor suppressor role of TOX3, our findings suggest that breast cancer low-risk loci generally do not affect expression of the nearest gene in breast tumor tissue. Also the prognosis of patients is largely not affected by low-risk breast cancer loci except for the SNP near H19. How, this SNP affects prognosis warrants further study as it does not operate through altering H19 mRNA expression.

Esposito F, Boscia F, Franco R, et al.
Down-regulation of oestrogen receptor-β associates with transcriptional co-regulator PATZ1 delocalization in human testicular seminomas.
J Pathol. 2011; 224(1):110-20 [PubMed] Related Publications
Oestrogen exposure has been linked to a risk for the development of testicular germ cell cancers. The effects of oestrogen are now known to be mediated by oestrogen receptor-α (ERα) and ERβ subtypes, but only ERβ has been found in human germ cells of normal testis. However, its expression was markedly diminished in seminomas, embryonal cell carcinomas and mixed germ cell tumours, but remains high in teratomas. PATZ1 is a recently discovered zinc finger protein that, due to the presence of the POZ domain, acts as a transcriptional repressor affecting the basal activity of different promoters. We have previously described that PATZ1 plays a crucial role in normal male gametogenesis and that its up-regulation and mislocalization could be associated with the development of testicular germ cell tumours. Here we show that ERβ interacts with PATZ1 in normal germ cells, while down-regulation of ERβ associates with transcriptional co-regulator PATZ1 delocalization in human testicular seminomas. In addition, we show that the translocation of PATZ1 from the cytoplasm into the nucleus is regulated by cAMP, which also induces increased expression and nuclear localization of ERβ, while this effect is counteracted by using the anti-oestrogen ICI 182-780.

Frenzel LP, Patz M, Pallasch CP, et al.
Novel X-linked inhibitor of apoptosis inhibiting compound as sensitizer for TRAIL-mediated apoptosis in chronic lymphocytic leukaemia with poor prognosis.
Br J Haematol. 2011; 152(2):191-200 [PubMed] Related Publications
Given that aggressive DNA damaging chemotherapy shows suboptimal efficacy in chronic lymphocytic leukaemia (CLL), alternative therapeutic approaches are needed. Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) is able to induce tumour-specific apoptosis. However, apoptosis might be inhibited by elevated levels of X-linked inhibitor of apoptosis (XIAP). Use of XIAP-inhibiting compounds might sensitize primary CLL cells towards TRAIL-mediated apoptosis. A novel small molecule, compound A (CA), an inhibitor of XIAP, was used in combination with TRAIL to induce apoptosis in primary CLL cells (n = 48). XIAP was significantly more highly expressed in primary CLL cells (n = 28) compared to healthy B cells (n = 16) (P = 0·02). Our data obtained by specific knock-down of XIAP by siRNA identified XIAP as the key factor conferring resistance to TRAIL in CLL. Combined treatment with CA/TRAIL significantly increased apoptosis compared to untreated (P = 8·5 × 10⁻¹⁰), solely CA (P = 4·1 × 10⁻¹²) or TRAIL treated (P = 4·8 × 10⁻¹⁰) CLL cells. CA rendered 40 of 48 (83·3%) primary CLL samples susceptible to TRAIL-mediated apoptosis. In particular, cells derived from patients with poor prognosis CLL (ZAP-70(+) , IGHV unmutated, 17p-) were highly responsive to this drug combination. Our highly-effective XIAP inhibitor CA, in concert with TRAIL, shows potential for the treatment of CLL cases with poor prognosis and therefore warrants further clinical investigation.

Patz M, Pallasch CP, Wendtner CM
Critical role of microRNAs in chronic lymphocytic leukemia: overexpression of the oncogene PLAG1 by deregulated miRNAs.
Leuk Lymphoma. 2010; 51(8):1379-81 [PubMed] Related Publications
MicroRNAs (miRNAs) are small, gene encoded RNAs which are able to influence gene expression in binding to the 3'UTR of mRNAs. Compared to healthy tissues, the global expression of miRNAs in cancerous tissue is frequently down-regulated. Likewise in chronic lymphocytic leukemia (CLL), down-regulation of several miRNAs has been reported. Analysis of miRNA promoters for epigenetic modifications revealed a stronger methylation of down-regulated miRNAs in CLL. To date, several target genes affected by deregulated miRNAs have been identified that have impact on CLL pathogenesis. The best-described consequence of miRNA deregulation is for miRNA-15/16 cluster deletion, which is frequently down-regulated in a subgroup of patients with CLL carrying 13q14 deletion. So far, models for miRNA deregulation have addressed just single miRNAs. For assessment of complete miRNA deregulation, further evaluation of the results from microarray studies is needed. Previously we identified the oncogene PLAG1, whose expression is affected by various miRNAs deregulated in CLL. The involvement of miRNAs in PLAG1 expression was shown to be relevant in pleomorphic adenomas of the salivary gland, too. As PLAG1 is highly overexpressed, and its target genes appear to be deregulated in CLL, e.g. BCL-2, PLAG1 is a putative new relevant oncogene involved in the pathogenesis of CLL.

Yang WL, Ravatn R, Kudoh K, et al.
Interaction of the regulatory subunit of the cAMP-dependent protein kinase with PATZ1 (ZNF278).
Biochem Biophys Res Commun. 2010; 391(3):1318-23 [PubMed] Free Access to Full Article Related Publications
The effects of cAMP in cell are predominantly mediated by the cAMP-dependent protein kinase (PKA), which is composed of two genetically distinct subunits, catalytic (C) and regulatory (R), forming a tetrameric holoenzyme R(2)C(2). The only known function for the R subunit is that of inhibiting the activity of the C subunit kinase. It has been shown that overexpression of RIalpha, but not the C subunit kinase, is associated with neoplastic transformation. In addition, it has also been demonstrated that mutation in the RIalpha, but not the C subunit is associated with increased resistance to the DNA-damaging anticancer drug cisplatin, thus suggesting that the RIalpha subunit of PKA may have functions independent of the kinase. We show here that the RIalpha subunit interacts with a BTB/POZ domain zinc-finger transcription factor, PATZ1 (ZNF278), and co-expression with RIalpha results in its sequestration in the cytoplasm. The cytoplasmic/nuclear translocation is inducible by cAMP. C-terminus deletion abolishes PATZ1 interaction with RIalpha and results in its localization in the nucleus. PATZ1 transactivates the cMyc promoter and the presence of cAMP and co-expression with RIalpha modulates its transactivation. Moreover, PATZ1 is aberrantly expressed in cancer. Taken together, our results showed a potentially novel mechanism of cAMP signaling mediated through the interaction of RIalpha with PATZ1 that is independent of the kinase activity of PKA, and the aberrant expression of PATZ1 in cancer point to its role in cell growth regulation.

Wasielewski M, Riaz M, Vermeulen J, et al.
Association of rare MSH6 variants with familial breast cancer.
Breast Cancer Res Treat. 2010; 123(2):315-20 [PubMed] Related Publications
Germline mutations in the mismatch repair genes MLH1, MSH2, MSH6, and PMS2 predispose to Lynch syndrome (also known as hereditary non-polyposis colorectal cancer). Recently, we have shown that the CHEK2 1100delC mutation also is associated with Lynch syndrome/Lynch syndrome-associated families albeit in a polygenic setting. Two of the ten CHEK2 1100delC positive Lynch syndrome families additionally carried a pathogenic MLH1 or MSH6 mutation, suggesting that mutations in mismatch repair genes may be involved in CHEK2 1100delC-associated cancer phenotypes. A phenotype of importance is hereditary breast and colorectal cancer (HBCC), with the CHEK2 1100delC mutation present in almost one-fifth of the families-again in a polygenic setting. In order to evaluate the involvement of MSH6 in polygenic CHEK2 cancer susceptibility, we, here, have analyzed the entire MSH6 coding sequence for genetic alterations in 68 HBCC breast cancer families. Rare MSH6 variants, with population frequencies below 1%, were identified in 11.8% of HBCC breast cancer families, whereas the same variants were identified in only 1.5% of population controls, suggesting that rare MSH6 variants are associated with HBCC breast cancer (P < or = 0.00001). However, screening of the entire MSH6 coding sequence in 68 non-HBCC breast cancer families showed a similar association (8.8 vs. approximately 1.4% in controls, P < or = 0.001), suggesting that rare MSH6 variants are not confined to HBCC breast cancer. Together, our data suggest that rare MSH6 variants may predispose to familial breast cancer. However, none of the rare MSH6 variants are obviously pathogenic, suggesting that a more subtle disease mechanism may operate in breast carcinogenesis.

Pallasch CP, Patz M, Park YJ, et al.
miRNA deregulation by epigenetic silencing disrupts suppression of the oncogene PLAG1 in chronic lymphocytic leukemia.
Blood. 2009; 114(15):3255-64 [PubMed] Free Access to Full Article Related Publications
MicroRNAs (miRNA) play a key role in cellular regulation and, if deregulated, in the development of neoplastic disorders including chronic lymphocytic leukemia (CLL). RNAs from primary cells of 50 treatment-naive CLL patients and peripheral B cells of 14 healthy donors were applied to miRNA expression profiling using bead chip technology. In CLL cells, a set of 7 up- and 19 down-regulated miRNAs was identified. Among the miRNAs down-regulated in CLL cells, 6 of 10 miRNA promoters examined showed gain of methylation compared with normal B-cell controls. Subsequent target prediction of deregulated miRNAs revealed a highly significant binding prediction at the 3' untranslated region of the pleomorphic adenoma gene 1 (PLAG1) oncogene. Luciferase reporter assays including site-directed mutagenesis of binding sites revealed a significant regulation of PLAG1 by miR-181a, miR-181b, miR-107, and miR-424. Although expression of PLAG1 mRNA was not affected, PLAG1 protein expression was shown to be significantly elevated in CLL cells compared with the levels in healthy donor B cells. In summary, we could demonstrate disruption of miRNA-mediated translational control, partly due to epigenetic transcriptional silencing of miRNAs, with subsequent overexpression of the oncogenic transcription factor PLAG1 as a putative novel mechanism of CLL pathogenesis.

Riaz M, Elstrodt F, Hollestelle A, et al.
Low-risk susceptibility alleles in 40 human breast cancer cell lines.
BMC Cancer. 2009; 9:236 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Low-risk breast cancer susceptibility alleles or SNPs confer only modest breast cancer risks ranging from just over 1.0 to 1.3 fold. Yet, they are common among most populations and therefore are involved in the development of essentially all breast cancers. The mechanism by which the low-risk SNPs confer breast cancer risks is currently unclear. The breast cancer association consortium BCAC has hypothesized that the low-risk SNPs modulate expression levels of nearby located genes.
METHODS: Genotypes of five low-risk SNPs were determined for 40 human breast cancer cell lines, by direct sequencing of PCR-amplified genomic templates. We have analyzed expression of the four genes that are located nearby the low-risk SNPs, by using real-time RT-PCR and Human Exon microarrays.
RESULTS: The SNP genotypes and additional phenotypic data on the breast cancer cell lines are presented. We did not detect any effect of the SNP genotypes on expression levels of the nearby-located genes MAP3K1, FGFR2, TNRC9 and LSP1.
CONCLUSION: The SNP genotypes provide a base line for functional studies in a well-characterized cohort of 40 human breast cancer cell lines. Our expression analyses suggest that a putative disease mechanism through gene expression modulation is not operative in breast cancer cell lines.

Hollestelle A, Nagel JH, Smid M, et al.
Distinct gene mutation profiles among luminal-type and basal-type breast cancer cell lines.
Breast Cancer Res Treat. 2010; 121(1):53-64 [PubMed] Related Publications
Breast cancer has for long been recognized as a highly diverse tumor group, but the underlying genetic basis has been elusive. Here, we report an extensive molecular characterization of a collection of 41 human breast cancer cell lines. Protein and gene expression analyses indicated that the collection of breast cancer cell lines has retained most, if not all, molecular characteristics that are typical for clinical breast cancers. Gene mutation analyses identified 146 oncogenic mutations among 27 well-known cancer genes, amounting to an average of 3.6 mutations per cell line. Mutations in genes from the p53, RB and PI3K tumor suppressor pathways were widespread among all breast cancer cell lines. Most important, we have identified two gene mutation profiles that are specifically associated with luminal-type and basal-type breast cancer cell lines. The luminal mutation profile involved E-cadherin and MAP2K4 gene mutations and amplifications of Cyclin D1, ERBB2 and HDM2, whereas the basal mutation profile involved BRCA1, RB1, RAS and BRAF gene mutations and deletions of p16 and p14ARF. These subtype-specific gene mutation profiles constitute a genetic basis for the heterogeneity observed among human breast cancers, providing clues for their underlying biology and providing guidance for targeted pharmacogenetic intervention in breast cancer patients.

Veldurthy A, Patz M, Hagist S, et al.
The kinase inhibitor dasatinib induces apoptosis in chronic lymphocytic leukemia cells in vitro with preference for a subgroup of patients with unmutated IgVH genes.
Blood. 2008; 112(4):1443-52 [PubMed] Related Publications
Src family kinases (SFKs) were described to be overexpressed in chronic lymphocytic leukemia (CLL). We wished to examine the effects of the Src and Abl kinase inhibitor dasatinib on the intracellular signaling and survival of CLL cells. Dasa-tinib showed a dose- and time-dependent reduction of global tyrosine phosphorylation and of activating phosphotyrosine levels of SFKs. Treatment with 100 nM dasatinib led to decreased levels of the activated, phosphorylated forms of Akt, Erk1/2, and p38, and induced PARP cleavage through caspase activity. In Mec1 and JVM-3 cell lines, dasatinib increased p53 protein levels and inhibited proliferation. In freshly isolated CLL cells, dasatinib reduced the expression of Mcl-1 and Bcl-x(L). Combination of 5 microM dasatinib and fludarabine increased the apoptosis induction of each by approximately 50%. In 15 primary CLL samples, cells with unmutated immunoglobulin variable heavy chain (IgV(H)) genes were more sensitive to dasatinib than those with mutated IgV(H) genes (P = .002). In summary, dasatinib shows potent inhibitory effects on the survival of CLL cells in vitro, most prominently in samples obtained from patients with unfavorable prognostic features.

Tian X, Sun D, Zhang Y, et al.
Zinc finger protein 278, a potential oncogene in human colorectal cancer.
Acta Biochim Biophys Sin (Shanghai). 2008; 40(4):289-96 [PubMed] Related Publications
Zinc finger protein 278 (ZNF278) is a novel Krueppel Cys2-His2-type zinc finger protein that is ubiquitously distributed in human tissues. Whether ZNF278 is related to the development of colorectal cancer is still unclear. The transcriptional level of ZNF278 was studied in colorectal cancer by real-time polymerase chain reaction. The results showed that ZNF278 expression was increased in 53% of colorectal cancer tissues compared to corresponding non-cancerous tissues. The transcriptional down-regulation of ZNF278 was detected in only three (6%) human colorectal cancer tissues compared to corresponding non-cancer tissues. No significant difference was detected in 19 (41%) pairs of samples. However, we failed to find a significant association between the up-regulation of ZNF278 transcription and age, sex, the degree of infiltration, or the tumor size of colorectal cancer. To study the function of ZNF278 in colorectal carcinogenesis, the colon cancer cell line SW1116 was stably transfected with a wild-type ZNF278 plasmid to construct an overexpression system, and was transiently transfected with the small interfering RNA of ZNF278 to construct a ZNF278 knockdown system. Cell proliferation was assessed with 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide dye and a cell counter. The results show that ZNF278 promotes cell growth, and its knockdown suppresses cell proliferation. ZNF278 could be a potential proto-oncogene in colorectal cancer.

Fedele M, Franco R, Salvatore G, et al.
PATZ1 gene has a critical role in the spermatogenesis and testicular tumours.
J Pathol. 2008; 215(1):39-47 [PubMed] Related Publications
PATZ1 is a recently discovered zinc finger protein that, due to the presence of the POZ domain, acts as a transcriptional repressor affecting the basal activity of different promoters. To gain insights into its biological role, we generated mice lacking the PATZ1 gene. Male PATZ1(-/-) mice were unfertile, suggesting a crucial role of this gene in spermatogenesis. Consistently, most of adult testes from these mice showed only few spermatocytes, associated with increased apoptosis, and complete absence of spermatids and spermatozoa, with the subsequent loss of tubular structure. The analysis of PATZ1 expression, by northern blot, western blot and immunohistochemistry, revealed its presence in Sertoli cells and, among the germ cells, exclusively in the spermatogonia. Since PATZ1 has been indicated as a potential tumour suppressor gene, we also looked at its expression in tumours deriving from testicular germ cells (TGCTs). Although expression of PATZ1 protein was increased in these tumours, it was delocalized in the cytoplasm, suggesting an impaired function. These results indicate that PATZ1 plays a crucial role in normal male gametogenesis and that its up-regulation and mis-localization could be associated to the development of TGCTs.

Auer RL, Riaz S, Cotter FE
The 13q and 11q B-cell chronic lymphocytic leukaemia-associated regions derive from a common ancestral region in the zebrafish.
Br J Haematol. 2007; 137(5):443-53 [PubMed] Related Publications
Loss of the long arm of chromosomes 11 and 13 is the most consistent cytogenetic abnormalities for patients with B-cell chronic lymphocytic leukaemia (B-CLL). They suggest the presence of as yet unidentified tumour suppressor genes within well-defined minimal-deleted regions (MinDRs). We have identified 38 orthologues of the human genes in MinDRs in zebrafish cDNA and syntenic regions for the human deletions in the zebrafish genome. One region on chromosome 9 in the zebrafish genome is of potential interest. Within chromosome 9, five genes and two microRNAs were identified with shared synteny to the MinDRs in B-CLL (two genes to human chromosome 11, three to human chromosome 13 and two chromosome 13 microRNAs). The critical region on zebrafish chromosome 9 maps to the MinDR for both human chromosomes, suggesting a common ancestry for B-CLL tumour suppressor genes. Target-selected mutagenesis to identify zebrafish mutants with knock-outs of genes in this region will allow analysis of their in vivo potential for lymphoproliferation and may define causative genes for B-CLL within human chromosomes 11q and 13q. Our study provides an explanation for involvement of both 11q and 13q in B-CLL and the potential to develop animal models for this common lymphoproliferative disorder.

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