bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 2963: The Foxp3 transcription factor expression in human gynecologic cancer cell lines
Authors: Ran Park Yu , Yong-Man Kim , Wha Lee Shin , Dae-Yeon Kim , Jong-Hyeok Kim , Joo-Hyun Nam , Young-Tak Kim
Published: February 2011

Objectives: The forkhead box protein 3 (Foxp3) transcription factor is considered as a master control gene for the function of regulatory T cells. However, recently some publications revealed that Foxp3 in cancer expressed higher than other tissues. A very recent publication describes the expression of Foxp3 in pancreatic carcinoma cells providing evidence that this could be an important tumor escape mechanism. As a result, some research considered that Foxp3 is associated with carcinogenesis, and cancer progression. To this end, This study was scheduled to investigate whether the expression of Foxp3 transcription factor can occur in gynecologic tumor types.

Materials and methods: Ten tumor cell lines of cervical, ovarian, breast cancer origins were selected. The cell lines of cervical cancer were SiHa, HeLa, and Caski. Ovarian cancers were OV-CAR-3, SK-OV-3, SNU-8, and SNU-251. MDA-MB-231, MCF-7,and T47-D were selected as breast cancer cell lines. They were maintained in specific medium (RPM1640, DMEM (Dulbecco's modified Eagle's medium)). The cell lines were cultured for a period of 2 weeks. Detection of Foxp3 mRNA was performed using both conventional quantitative real-time PCR, the RT2 PCR Primer Set for Foxp3 (SuperArray, USA, forward 5’ GGCATCGTGATGGACTCCG 3’ and reverse 5’ GCTGGAAGGTGGACAGCGA 3′). β-Actin was used as a reference gene. All experiments were repeated three times.

Results: The expression of Foxp3 mRNA was revealed in all tumor cell lines studied. This expression did not relate to the tissue of origin of each line. Relative expression values for tumor cells varied widely between 0.21 and 4.97 (1.71±0.09). Cervical cancer cell lines expressed highly Foxp3 mRNA in relative expression values for tumor cells. The highest expression level of Foxp3 in cervical cancer cell lines were with the SiHa cell lines. OV-CAR-3 cell lines expressed highly in ovarian cancer cell lines. In breast cancer cell lines, Foxp3 mRNA expression revealed the highest levels in T47-D cell lines.

Conclusion: Foxp3 mRNA was detected in all tumor cell lines, albeit in variable levels, not related to the origins of tissue. We offer evidence that Foxp3 mRNA expression, characterizes tumor cells of various tissue origins. The biological significance of these findings warrants further investigation in the context of tumor immune escape, and especially under the light of current anti-cancer efforts interfering with Foxp3 expression.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2963.
Abstract 2964: YB-1 expression in early hematopoiesis and leukemic cells
Authors: Bhullar Jasjeet , Sollars Vincent E.
Published: February 2011

Hematopoietic transcription factors play a critical role in directing the commitment and differentiation of hematopoietic stem cells (HSC) along a particular lineage. Y box protein (YB-1), a cold shock family protein is a transcription factor which is widely expressed throughout development and has been implicated as a cell survival factor that regulates transcription and translation. YB-1 is known to be involved in erythroid cell development by interacting with Globin Transcription Factor (GATA); this study aims to investigate YB-1 expression in normal hematopoietic differentiation and leukemia. EML-clone 1 cells, a murine hematopoietic stem cell line, was used as a model for looking at the expression of YB-1 during myeloid differentiation by western blotting and quantitative RT-PCR. Fluorescence activated cell sorting was conducted to isolate lineage——/IL-7R—/c-kit+/Sca1+ (LKS) hematopoietic stem, lineage——/IL-7R—/c-kit+/Sca1— myeloid progenitor cells and granulocytes from mouse bone marrow to assess the YB-1 expression in vivo. YB-1 protein levels were analyzed in a panel of myeloid leukemic cell lines by immunoblotting. YB-1 mRNA and protein levels were high in the EML cells but the expression goes down in RA/IL-3 treated EML-clone 1 cells (myeloid progenitors) and was even more dramatically down-regulated in GM-CSF treated EML cells during the course of myeloid differentiation. Interestingly, LKS (enriched fraction of hematopoietic stem cells) and myeloid progenitor cells showed high level of YB-1 expression as compared to the differentiated cells like granulocytes. Further, we observed that YB-1 protein was expressed in several myeloid leukemic cell lines blocked at different stages of myeloid development. Thus, our data suggest that YB-1 is down-regulated during myeloid differentiation and it might be involved in hematopoietic differentiation. Aberrant YB-1 expression could be a contributing factor in the development of leukemia thus making it an excellent molecular target for therapy in myeloproliferative disorders and leukemia.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2964.
Abstract 2965: Dissecting the molecular mechanism of TLX1-mediated T-cell acute lymphoblastic leukemia development using an in vitro immortalization model
Authors: Zweier-Renn Lynnsey A. , Hawley Teresa S. , Ramezani Ali , Riz Irene , Hawley Robert G.
Published: February 2011

Inappropriate activation of the TLX1 homeobox gene (previously known as HOX11) by chromosomal translocation is a recurrent event in human T-cell acute lymphoblastic leukemia (T-ALL). Enforced expression of TLX1 in murine hematopoietic stem/progenitor cells using a conventional retroviral vector yields immortalized hematopoietic progenitor cell lines. Recent clinical gene therapy trials have shown that retroviral vectors can cause insertional activation of proto-oncogenes which has resulted in the development of hematopoietic clonal dominance or T-ALL-like diseases. Our lab has developed an insulated self-inactivating retroviral vector, RMSinOFB, which has been safety-modified to virtually eliminate insertional genotoxicity during transgene delivery. To observe the effect of reducing retroviral genotoxicity during TLX1 gene transfer, we subcloned the TLX1 gene into the RMSinOFB vector for ectopic expression in murine hematopoietic stem/progenitor cells. Post transduction, TLX1-expressing bone marrow cells had a growth/survival advantage, and readily gave rise to immortalized cell lines. To determine whether insertional mutagenesis played a role in TLX1-mediated immortalization, we identified the integration sites in 15 TLX1-immortalized hematopoietic cell lines by LM-PCR. No common immortalizing genes, such as Evi1 or Prdm16, were identified among the cell lines which underlines the importance of TLX1 transcriptional properties for cell immortalization. Additionally, when tested by RT-PCR no differential vector-influenced expression was observed for candidate genes nearest the integration sites compared to the cell lines lacking such insertions. Furthermore, gene ontology analysis of genes within 100-kb windows of the integration sites did not reveal overrepresentation of a particular functional group. Although several laboratories recently reported the generation of hematopoietic progenitor cell lines due to insertional mutagenesis by retroviral vector backbones, these results confirm and extend our previous findings suggesting that constitutive TLX1 expression alone is sufficient to initiate the series of events culminating in hematopoietic progenitor cell immortalization. We are currently investigating whether non insertion site-related mutations, such as inactivation of the Cdkn2a tumor suppressor locus which collaborates with TLX1 during human T-cell leukemogenesis, may contribute to the process. Investigating the molecular mechanism of TLX1-mediated cellular immortalization in our in vitro model should provide a better understanding of the early stages of TLX1-associated T-ALL development.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2965.
Abstract 2968: Aberrant expression of polycystin-1 in renal cell tumors
Authors: Gogusev Jean , Chretien Yves , Droz Dominique
Published: February 2011

Polycystin-1 (PC1) is a cellular transmembrane protein encoded by the polycystic kidney disease gene (PKD1) prevalently expressed in developing/mature kidney and in autosomal polycystic kidney disease (ADPKD). Limited data are available concerning the PC1 involvement in renal tumorigenesis.

Polycystin-1 expression was evaluated by immunohistochemistry (IHC) in 8 clear cell renal cell carcinomas (RCCs), 7 tubulopapilary cell type tumors, 3 solid RCCs developed in patients with von Hippel-Lindau disease (VHL), one RCC developed in a patient on chronic haemodyalisis and one angyomyolipoma in a patient with Tuberous sclerosis (TS). In parallel, the BIZ cell line derived from a high grade clear cell RCC and the WUR cell line derived from a tubulopapillary type RCC, were used to measure the level of PC1 expression by both immunolabeling and immunoblotting analyses.

Five cases of clear cell type RCCs, and two tubulopapillary cell type RCCs consistently expressed PC1 with a percentage of labeled neoplastic cells ranging between 15% and 65%. Un the VHL disease-associated renal cell carcinoma, both the tumor cells and cystic tissues areas weakly expressed the PC1 protein. In TS-associated angiomyolipoma, the vascular component was PC1 positive, while the tumor cells were scarcely stained. High level of expression of PC1 was confirmed by both IHC and immunoblotting in WUR RCC cells (80% of labeled cells), while BIZ RCC cells exhibited a moderate PC1 staining (30% of labeled cells). Comparatively, in the normal kidney, consistent level of polycystin 1 was detected in distal tubules, collecting duct, glomerular podocytes and vascular smooth muscle cells. The strongest immunoreactivity against PC1 was observed in epithelial cells lining the cystic components in all ADPKD tissues.

In conclusion, the presented data indicate consistent level of expression of the polycystin-1 protein in a number renal cell carcinomas and suggest that PC1 expression is linked to the tumor cell type, being more frequent event in clear cell type RCC.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2968.
Abstract 2971: Genomic instability of breast stroma
Authors: Rummel Seth , Ellsworth Rachel E. , Kane Jennifer , Deyarmin Brenda , Hooke Jeffrey A. , Ellsworth Darrell L. , Shriver Craig D.
Published: February 2011

Background: Research in the past decade has demonstrated the importance of the tumor microenvironment in breast cancer development and progression. Allelic imbalance evaluation of tumor and stromal components suggests a limited number of alterations in the tumor may lead to cellular transformation while tumor behavior may be driven by molecular changes in the surrounding stroma. Recent studies evaluating copy number changes in frozen stromal tissue, however, found no chromosomal alterations and suggested that earlier studies represent artifacts from the use of archive tissues.

Methods: High-quality flash-frozen specimens were collected from breast quadrants from 14 patients undergoing mastectomy; patient characteristics ranged from prophylactic mastectomy to stage IV breast cancer. DNA was isolated (Gentra) from benign tissue sections and hybridized to GeneChip Human Mapping 250K arrays (Affymetrix). Genomic DNA from peripheral blood for each patient was genotyped to assess copy number variation (CNV) by paired analysis. CNVs were identified using Genome Console 3.0.2 (Affymetrix) with a minimum genomic size/fragment of 500 Kb and a minimum of 50 markers/segment.

Results: Copy number changes ranging in size from 586-5061 kb were detected in 50% (7/14) patients in at least one quadrant, with a single patient having copy number changes present in each quadrant. 21% of quadrants (12/57) showed detectable copy number changes affecting 1 - 18 chromosomal arms. Copy number changes were detected not only in stroma from diseased breasts, but in prophylactic mastectomies, as well. Copy number changes were observed in all quadrants irrespective of tumor location. While copy number alterations on chromosomes 1q21, 2p21, 12p13, 14q12 and 18q12 were shared between patients, no patient had the same patterns of CNVs across all quadrants.

Conclusions: Chromosomal alterations were detected in high-quality frozen breast stroma specimens utilizing genome-wide SNP array data, supporting earlier claims that breast stroma may be genetically unstable. Half of the patients in this study demonstrated copy number alterations in breast stroma distant from the tumor, suggesting that for a subgroup of breast cancer patients, widespread chromosomal instability may increase risk of recurrence.

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2971.
Abstract 2975: Two putative founder MSH6 mutations associated with inherited cancer susceptibility in Ashkenazi Jewish population
Authors: Schwenter Frank , Raskin Leon , Freytsis Marina , Bogomolniy Faina , Aronson Melyssa , Rennert Gad , Gallinger Steven , Levine Douglas A. , Tischkowitz Marc , Gruber Stephen B. , Foulkes William
Published: February 2011

Background

Inherited mutations in DNA mismatch-repair genes are the cause of several cancers associated with Lynch syndrome. The most common mutations affect MLH1 and MSH2 genes, while the MSH6 gene is less commonly involved. Furthermore, MSH6 mutations have been observed to result in an attenuated form of the syndrome. We report here case-control studies of two putative MSH6 founder mutations in the Ashkenazi Jewish (AJ) population.

Methods

Case-control studies were performed using DNA extracted from the blood of individuals of AJ descent presenting cancers compatible with Lynch syndrome and AJ individuals unaffected by cancer as controls. The DNA samples were screened for the presence of the two mutations in exon 9. The frequency of the mutations and the range of malignancies were analyzed.

Results

Among 2104 population-based AJ colorectal cancer cases (CRC), 8 carried a 4 bp duplication mutation, c.3984_3987dupl (0.38%), and 3 carried a 4 bp deletion mutation, c.3959_3962del (0.14%), in the exon 9 of the MSH6 gene. In comparison, 1 duplication (0.06%) and no deletions were observed in 1813 control individuals. The odds ratio for the c.3984_3987dupl and the c.3959_3962del in this population are OR = 8.64 (exact 95%CI 1.23-375, Fisher's exact test two-sided P = 0.04) and OR = NA, P = 0.25, respectively. Notably, the one control found to carry the duplication was, during the course of follow-up, diagnosed with both cecal and endometrial cancer. In a hospital-based series of 78 CRC, one individual carried the deletion, but no duplications were seen. Among 136 hospital-based AJ endometrial cancer cases, 2 carried the duplication, leading to an OR of 27.0 (95%CI: 1.39-1596, P = 0.014) when compared with the 1813 controls. In a series of 61 hospital-based AJ pancreas cancer cases, no duplication carriers were seen, but 1 individual carried the deletion (OR NA, P = 0.033). Notably, this individual developed 3 independent primary cancers - pancreas cancer, CRC and rhabdomyosarcoma. Testing for microsatellite instability and loss of MSH6 protein is in progress in these samples.

Conclusion

These rare, probable founder, MSH6 truncating mutations reported here are of great importance for the screening, genetic counseling and follow-up of Ashkenazi Jewish families presenting malignant tumors compatible with Lynch syndrome.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2975.
Abstract 2977: LSD1 is Required for Chromosome Segregation during Mitosis
Authors: Lv Shuang , Bu Wenjuan , Jiao Hong , Liu Bo , Zhu Lin , Zhao Hongchang , Liao Ji , Li Jing , Xu Xingzhi
Published: February 2011

Dynamic methylation/demethylation of histones and non-histone proteins occurs during the cell cycle. Lysine-specific demethylase 1 (LSD1) exhibits diverse transcriptional activities through catalyzing demethylation of mono- and di-methylated histone H3 on lysine 4 (H3K4) and lysine 9 (H3K9). We show here that inhibition of LSD1 expression by siRNA leads to abnormal chromosomal segregation in unperturbed mitosis and abnormal centrosome duplication, and is associated with decreased protein levels of MAD2 and BUBR1. LSD1 positively regulates the BUBR1 and MAD2 promoter activity and maintains local monomethylation status of H3K9, which is a repressive histone mark for gene transcription. Expression of exogenous BUBR1 and MAD2 in LSD1-depleted cells partially rescues the defect of chromosome segregation. Our results suggest that LSD1 plays a role in chromosomal segregation during mitosis partially through transcriptional regulation of BUBR1 and MAD2.

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2977.
Abstract 2978: Nucleotide excision repair contributes to hexavalent chromium-induced double strand breaks and chromosomal damage
Authors: Savery Laura C. , O'Brien Travis J. , Holmes Amie L. , Wise John P. , Patierno Steven R.
Published: February 2011

Certain hexavalent chromium (Cr(VI)) compounds are known human lung carcinogens. Cr(VI) causes several types of DNA damage including bulky adducts and crosslinks. Cr(VI)-induced tumors exhibit chromosomal instability (CIN), however, very little is known about mechanisms of these effects and the role that DNA repair plays in this process. Nucleotide excision repair (NER) is known to be involved in the repair of bulky DNA damage. Unrepaired or misrepaired lesions can lead to chromosomal aberrations (CAs). We investigated the role of NER leading to CAs using Chinese hamster ovary (CHO) parental (AA8) and NER-deficient cells (UV-5). We found that UV-5 cells displayed attenuated Cr(VI)-induced chromosome damage. In general, DNA lesions need to be converted to DNA double strand breaks (DSBs) in order to give rise to CAs. Therefore, we used the neutral Comet assay to measure the induction and repair of DSBs after Cr(VI)-induced damage. We found that both parental and NER-deficient cell lines displayed low levels of DSBs immediately after Cr(VI) treatment. Interestingly, DSB formation peaked after a 24h recovery period, and NER-deficient cells exhibited lower overall levels of DSBs than repair-proficient cells. All damage in both cell lines was repaired by 48h following Cr(VI) exposure. Taken together, our results suggest that Cr(VI)-induced DSBs are not directly formed by Cr(VI) exposure. Instead, these lesions develop as a consequence of repair of, or replication past, Cr(VI)-induced lesions. Importantly, our data suggests that NER contributes to Cr(VI)-induced genomic instability.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2978.
Abstract 298: Mutant PIK3CA increases the expression of individual tubulin isoforms and promotes resistance to anti-mitotic chemotherapy drugs
Authors: Wallin Jeffrey J. , Guan Jane , Xiao Yang , O'Brien Tom , Belvin Marcia , Friedman Lori S.
Published: February 2011

Resistance to many anti-cancer agents has been attributed to increased PI3K/PTEN pathway signaling. Hence, inhibitors of the pathway have potential utility in combination with these therapies. To investigate chemotherapy drug sensitivities downstream of mutant PIK3CA in a controlled and patient-relevant context we utilized human non-tumorigenic MCF10A parental and isogenic knock-in cell lines that harbor a common activating PIK3CA kinase domain mutation (H1047R). We found the mutant cells to be least sensitive to anti-mitotic drugs, but the resistance could be overcome in combination with GDC-0941, a Class I PI3K inhibitor currently being evaluated in clinical trials. To understand the mechanism of resistance we analyzed microarray data for expression of known anti-mitotic resistance genes. We found that a subset of tubulin isoforms were increased with PI3K pathway signaling, but were reduced with GDC-0941 treatment. The changes in mRNA expression were confirmed at the protein level and were extended to additional cell lines. RNAi knockdown of TUBB2, the isoform we found to be most influenced by PI3K pathway signaling, increased the sensitivity of both parental and H1047R clones to anti-mitotic drugs, but did not influence GDC-0941 potency. Thus, reduced expression of the target increases the potency of the anti-mitotic drug. Overall, these findings suggest a mechanism of action for anti-mitotic drugs in combination with inhibitors of PI3K.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 298.
Abstract 2981: Regulation of Snail by DDX3 and ATM in response to DNA damage
Authors: Sun Mianen , Zhou Tong , Gillespie Yancey , Xu Bo , Jope Richard
Published: February 2011

Epithelial-mesenchymal transition (EMT) is the initial step for cancer invasion and metastasis. The hallmark of EMT is the loss of expression of E-cadherin, a cell-cell adhesion protein, allowing cancer cells to gain mobility leaving the site of primary tumor to invade adjacent tissues. Snail, as a transcription repressor, binds to the E-boxes of E-cadherin and then inhibits E-cadherin expression. Thus, Snail is essential to trigger EMT during tumor progression and it has been implicated in the acquisition of invasive growth phenotype of tumors. There is a strong correlation of Snail over-expression with tumor invasion and metastasis. However, how Snail expression is regulated is not fully known. Here we report that Snail is regulated by DDX3, a DEAD box protein family member which contributes to cancer progression. Knock-down of DDX3 by shRNA reduces the basal level of Snail, and this is associated with reduced cell proliferation and migration. Snail protein and mRNA levels are increased in the presence of the HDAC inhibitors sodium butyrate or trichostatin A, and the increases are attenuated in cells with DDX3 knocked down. Treatment of cells with a DNA damaging agent camptothecin also enhances Snail protein levels in a DDX3 dependent manner. Therefore we conclude that DDX3 is required for the basal level and the increase in Snail induced by HDAC inhibitors or camptothecin, indicating that this action of DDX3 may contribute to its promotion of the progression of some cancers. This conclusion is supported by our clinical investigations that analysis of 31 glioblastoma patient samples has revealed a strong correlation between the levels of DDX3 and Snail. Snail is a phosphor-protein, and kinases responsible for phosphorylation include Pak1 and GSK3-β. We also find Pak-1 and GSK-3 independent Snail phosphorylation in response to DNA damage. Further we find that inhibition of the activity of the ATM kinase, a critical element in DNA damage responses, eliminated DNA damage-induced Snail stabilization. Taken together, these observations have highlighted a comprehensive signaling network regulating Snail in response to DNA damage and indicated a critical role of optimal DNA damage responses in tumor invasion and metastasis.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2981.
Abstract 2983: Che-1 promotes tumor cell survival by sustaining mutant p53 transcription and inhibiting DNA damage response activation
Authors: Bruno Tiziana , Santis Agata De , Bossi Gianluca , Agostino Silvia Di , Sorino Cristina , Nicola Francesca De , Iezzi Simona , Franchitto Annapaola , Benassi Barbara , Floridi Aristide , Bellacosa Alfonso , Passananti Claudio , Blandino Giovanni , Fanciulli Maurizio
Published: February 2011

Che-1 is a RNA polymerase II binding protein involved in the regulation of gene transcription, and in response to DNA damage promotes p53 transcription. In this study, we investigated whether Che-1 regulates mutant p53 expression. We found that Che-1 is required for sustaining mutant p53 expression in several cancer cell lines, and Che-1 depletion by siRNA induces apoptosis both in vitro and in vivo. Notably, loss of Che-1 activates DNA damage checkpoint response and induces transactivation of p73. Therefore, these findings suggest a new therapeutic approach that allowing simultaneous modulation of p73 and mutant p53 levels might be used to target the large fraction of human tumors harboring p53 mutations.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2983.
Abstract 2985: DNA-damage related histone marks can distinguish the anti-tumor effects of established and novel histone deacetylase inhibitors in ovarian cancer cells
Authors: Wilson Andrew J. , Holson Ed , Bhaskara Srividya , Carlise Jahred , Schreiber Stuart L. , Hiebert Scott W. , Khabele Dineo
Published: February 2011

The majority of epithelial ovarian carcinomas harbor molecular alterations in DNA-damage response genes. Epithelial ovarian cancers are surprisingly sensitive to DNA-damaging platinum-based (cisplatin or carboplatin) chemotherapy, suggesting that the dependencies of ovarian cancers on impaired DNA-damage response pathways can be harnessed for therapeutic purposes. Our group and others have shown that histone deacetylase (HDAC) inhibitors are promising anti-tumor agents, particularly when combined with DNA-damaging drugs in ovarian cancer cells. In this study, H2AX phosphorylation (pH2Ax), a known histone mark of DNA damage and other histone marks related to DNA damage and repair pathways, including the newly recognized acetylated lysine K56 on histone 3 (H3K56ac) were used to distinguish the biological effects of a unique and diverse panel of clinically utilized and novel HDAC inhibitors. Ovarian cancer cell lines with diverse molecular alterations, including mutations in p53, Brca1, Akt, Ras, and overexpression of MDR1, were utilized in these screens. The HDAC inhibitors that induced the highest levels of pH2Ax produced the greatest anti-tumor effects (growth inhibition and apoptosis). Furthermore, a screen of DNA-damage response histone marks led to the selection of novel HDAC inhibitors that exerted synergistic anti-tumor effects when combined with cisplatin and other DNA-damaging drugs. Taken together, our results support a role of HDAC inhibitors in the treatment of ovarian cancer and suggest that pH2Ax is a potential surrogate biomarker of the efficacy of HDAC inhibitor combination therapy with DNA-damaging agents.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2985.
Abstract 2988: A PP6-phosphatase complex is required for homology-directed repair of DNA double-strand breaks
Authors: Zhong Jianing , Liao Ji , Yao Lu , Liu Jinping , Stark Jeremy , Lees-Miller Susan , Xie Yuntao , Xu Xingzhi
Published: February 2011

DNA double-strand breaks (DSBs) are among the most lethal lesions associated with genome stability which, when destabilized, predisposes organs to cancers. DSBs are primarily fixed either with little fidelity by non-homologous end joining (NHEJ) repair or with high fidelity by homology-directed repair (HDR). The phosphorylated form of H2AX on serine 139 (g-H2AX) is a marker of DSBs. It is dephosphorylated by PP2A-like protein phosphatases (PP2A, PP4, and PP6). Here, we identify three novel PP6 subunits. Several PP6c (the catalytic subunit of PP6)-containing heterotrimeric complexes show phosphatase activities against g-H2AX in the in vitro phosphatase assays using bacterially-produced proteins, providing direct evidence that the PP6 holoenzyme is a PP6c-containing heterotrimeric complex. Furthermore, depletion of PP6c, PP6R2, or MyPT1 leads to defective HDR, and expression of phosphatase-inactive PP6c fails to rescue this defect. Chromatin immunoprecipitation assays demonstrated that PP6c is recruited to the region adjacent to the DSB sites. Expression of PP6R2, but not PP6c or MyPT1, is associated with improved overall survival in patients with breast cancer at five years (n=100, p=0.038). Taken together, our results suggest that the PP6-PP6R2-MyPT1 complex is required for HDR and PP6R2 is a potential therapeutic target.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2988.
Abstract 2989: Depletion of the Topoisomerase I binding proteins BTBD1 and BTBD2 alters the DNA damage response in tumor cells treated with camptothecin
Authors: Kurtis Christian , D'Arpa Peter , Cutler Mary L.
Published: February 2011

The Topoisomerase I (Top1) binding proteins BTBD1 and BTBD2 belong to a family of structurally related proteins of diverse function. BTBD1 and BTBD2 are highly homologous (>80% identity) and are comprised of an N-terminal BTB/POZ domain, typically involved in protein-protein interactions, followed by a related BACK (BTB and C-terminal Kelch) domain. The carboxy-terminal half of these proteins have been shown to be the Top1 binding portion (Xu et al., 2002) and contain a PHR domain found in certain E3 ubiquitin ligases. Understanding the role of BTBD1 and 2 proteins, with an emphasis on the effects of their depletion by RNAi and concomitant treatment of cells with the Top1 specific camptothecin (CPT) family of chemotherapeutic agents, is the focus of this present study. Treatment of cells with CPT and related analogues results in Top1 mediated DNA damage that was assayed by detection of the phosphorylation of DNA damage response elements (DDRE), including ATM, ATR, Chk1 and H2A.X, by Western blot. We have observed a >5-fold activation of the basal levels of DDRE in cells in which BTBD1 and BTBD2 have been depleted by RNAi. Furthermore, the response to CPT in these cells is temporally accelerated compared to cells treated with a non-specific control siRNA and CPT. In addition, immunofluorescent studies have revealed that there is a clearing of Top1 from the nucleoli of BTBD1 and 2-depleted cells even in the absence of CPT treatment. Recently characterized members of the BTB family of proteins have been shown to be involved in the repair of DNA damage (Munoz et al., 2009). It appears that BTBD1 and 2 proteins are involved in the response to DNA damage induced by Top1 specific drugs and as such open a new area of study with potential for development of novel combination therapies.

Xu L, et al., BMC Genomics. 2002. 3(1).

Muñoz IM, et al., Mol Cell. 2009. 35:116-27.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2989.
Abstract 2990: Analysis of chromatin structure in the Myeloid-Lymphoid Leukemia gene translocation breakpoint cluster region
Authors: Horrell Jeremy C. , Aldrich Aileen M. , Super Heidi J. Gill
Published: February 2011

The Myeloid-Lymphoid Leukemia (MLL) gene fuses to >50 different loci as the result of reciprocal translocations associated with several subtypes of human acute leukemia. In every case, the fusion point in MLL is within the same 8 kilobase pair (kbp) region, called the MLL breakpoint cluster region (bcr). Despite this conserved breakpoint, no translocation mechanism has been definitively described. Recently, electrophoretic mobility shift assay (EMSA) was used to determine protein binding characteristics in the MLL bcr. Proteins were noted to bind at the extreme 5’ and 3’ boundaries of the MLL bcr, but not in an internal region near the 3’ end of the MLL bcr which includes the translocation breakpoint hot spot in infant and therapy-related acute myeloid leukemia patients. The limited mobility observed with the protein-DNA complexes indicate a large protein or multiple proteins may bind at the 5’ and 3’ ends of the MLL bcr. Binding occurred with nuclear proteins from hematopoetic cells, but not with nuclear proteins from fibroblast cells and was sequence-specific as shown by competitor assays. Analysis of the most 5’ region of the MLL bcr showed several discontinuous regions are important for protein binding. Our results suggest that specific protein-DNA interactions may define the limits of the MLL bcr, and that the previously described internal hotspot does not bind the same protein complex. Binding of proteins at the boundaries of the MLL bcr prompted a study of chromatin organization within the same regions of the MLL bcr. Our initial hypothesis was that the MLL bcr regions which bound the protein complex would be relatively nucleosome depleted. Using chromatin immunoprecipitation assay (ChIP), we consistently showed a lack of histone H3 at the extreme 5’ end of the MLL bcr in Hela cells, and in the B-cell leukemia cell line, REH, suggesting a nucleosome-depleted region. In repeated experiments the 3’ MLL boundary showed minimal histone H3 binding, suggesting this area is also relatively free of nucleosomes. The internal breakage hot spot showed prominent H3 binding consistent with the presence of nucleosomes. The chromatin study suggests that the MLL bcr boundary regions are more exposed, especially in the 5’ region. This further supports our EMSA findings, that the MLL bcr may be bordered by large DNA-protein complexes. The project described was supported by NIH Grant Number P20 RR016741 from the North Dakota INBRE Program of the National Center for Research Resource, and by a Minot State University institutional research grant.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2990.
Abstract 2994: Benzene induces leukemia-related chromosome loss in myeloid progenitor cells
Authors: Zhang Luoping , Lan Qing , Ji Zhiying , Li Guilan , Guo Weihong , Shen Min , Hubbard Alan , Vermeulen Roel , Rappaport Stephen , Rothman Nathaniel , Smith Martyn T.
Published: February 2011

Benzene, a common environmental pollutant, is an established cause of acute myeloid leukemia (AML) and other blood disorders, such as myelodysplastic syndromes (MDS). However, the precise mechanisms by which it produces leukemia and related disorders remain unclear. Previously, we reported that benzene exposure, at and below the current US occupational standard of 1 ppm, significantly reduced essentially all types of peripheral blood cell counts in shoe workers in China (Lan et al, 2004). This suggests a toxic effect of benzene on bone marrow since all peripheral blood cells arise from stem and early progenitor cells located in the bone marrow, which are also the target cells for leukemia induction. A portion of these stem and early progenitor cells circulate in the blood making it possible to measure their proliferation potential. We previously showed that colony formation from blood myeloid progenitor cells (including CFU-GM and CFU-GEMM) significantly declined with increasing benzene exposure and was more sensitive to the effects of benzene than was the number of mature blood cells (Lan et al, 2004). We have now investigated the effect of different levels of benzene exposure on the loss and gain of chromosomes 7 and 8, as these are the most common cytogenetic changes observed in AML and MDS and are thought to be causally related to the disease process. CFU-GM cells were cultured in methylcellulose colony-forming assays (StemCell Technologies) from a subset (n = 42) of the workers studied previously (18 workers exposed to <10 ppm, 10 exposed to >10 ppm benzene and 14 unexposed controls) for cytogenetic analysis by interphase FISH (fluorescence in situ hybridization) microscopically. Here, we report that benzene exposure above and below 10 ppm caused significant increases in the loss (monosomy) of chromosomes 7 and 8 in comparison to controls and that the trend with increasing exposure was significant (ptrend < 0.01). The gain (trisomy) of both chromosomes 7 and 8 was not significantly affected by benzene exposure in the 42 subjects studied here. In conclusion, interphase cytogenetic analysis of the loss of chromosomes 7 and 8 in myeloid progenitors is a potential biomarker for the effects of benzene exposure in humans. Further, our results support the idea that the loss of chromosome 7 in early myeloid progenitor cells is a probable mechanism contributing to benzene-induced AML and MDS. Supported by NIEHS-NIH grant RO1-ES06721 and Intramural Funds from NCI.

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2994.
Abstract 2998: MicroRNA expression signatures in human ovarian tumor progression
Authors: Zhao Jian-jun , Kong William , Lin Jianhong , Wey Jennifer , Yang Hua , coppola domenico , Lee Yi-Chun , Wenham Robert , Lancaster Johnathan , Sellers Thomas , Cheng Jin Q.
Published: February 2011

Differential expression of a number of miRNAs has previously been detected between normal ovaries and epithelial ovarian cancer (EOC). However, miRNA expression signatures have not been demonstrated between primary human ovarian surface epithelial (HOSE) cell, cystadenoma, low malignant potential (LMP) ovarian tumor and ovarian carcinoma as well as fallopian tube. Here, we performed miRNA profiling in normal primary OSE cells, normal fallopian tube and ovarian tumors, including 7 cystadnomas, 6 LMP and 49 ovarian carcinomas, as well as 15 ovarian cancer cell lines and 5 HIOSE cell lines. While deregulated dozen miRNAs were observed in different histological types of cysadenoma, LMP and ovarian carcinoma compared to primary OSE and fallopian tube, there are no significantly common changed miRNAs between serous adenoma and LMP, as well as between mucinous adenoma and LMP. However, 3 miRNAs were co-downregulated and 7 miRNAs were co-upregulated in serous LMP and carcinoma. When comparing mucinous LMP and carcinoma, only 3 miRNAs were co-deregulated. In addition, 3 and 6 miRNAs were co-deregulated in mucinous and serous adenoma and carcinoma, respectively. While miRNA expression patterns are distinct among four histological types of ovarian carcinoma examined, upregulation of miR-221/222 family was found to have significant poor prognosis value in serious carcinoma (p<0.05). These results support the notion that majority of ovarian carcinoma are derived neither from cystadenoma nor from LMP. Further cluster analysis suggests that the serious ovarian cancer may be derived from fallopian tube or/and OSE. Also our data suggest that commonly deregulated miRNAs between adenoma, LMP and carcinoma could serve as not only early markers but also initiation pathogenetic factors in this malignancy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2998.
Abstract 2999: Assessment of microRNA expression in two-dimensional histopathological fields of breast cancer
Authors: Rosenberg Alex M. , Zoon Christine K. , Clark Elizabeth S. , Armani Michael D. , Shapiro Benjamin , Smela Elisabeth , Hanson Jeffrey C. , Rodriguez-Canales Jaime , Emmert-Buck Michael R. , Tangrea Michael A.
Published: February 2011

Breast cancer is the second most common type of cancer among women with an expected ∼192,000 newly diagnosed cases in the United States this year alone. Early detection methods are becoming increasingly important for guiding treatment options and decisions. Currently, standard molecular diagnostic tests of breast cancer characterize patient cases by estrogen receptor (ER), progesterone receptor (PR) and Her2neu status. The recently discovered biomolecule, microRNA (miRNA), is being assessed as a novel diagnostic tool; however, since miRNA is a regulatory molecule it is likely that expression is cell-type and location specific, thus studies that don't specifically study malignant and normal cells may mask miRNA patterns within tissue. The goal of our study was to evaluate miRNA expression within sub-regions of formalin-fixed paraffin-embedded breast cancer tissue. Utilizing a combination of laser-based and manual microdissection techniques, we evaluated the expression of several breast cancer associated miRNA via TaqMan chemistry. We dissected selected areas of tumor and normal cells, as well as a grid-like pattern over entire tissue sections to separately evaluate each histopathological region. The data suggest there is heterogeneity of miRNA expression within the tumor and the surrounding normal tissue. In order study this phenomenon in more detail, we are now adapting a new two-dimensional amplification (2D-PCR) device to measure miRNA levels across tissue specimens with fine resolution. This approach to examining miRNA profiles in tissue sections may lead to novel findings with diagnostic or prognostic implications for breast cancer patients.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2999.
Abstract 30: ERG oncoprotein expression in prostate cancer: Potential for ERG-based stratification
Authors: Tan Shih-Han , Furusato Bungo , Young Denise , Dobi Albert , Sun Chen , Mohamed Ahmed , Thangapazham Rajesh , Chen Yongmei , McMaster Gary , Sreenath Taduru , Petrovics Gyorgy , McLeod David G. , Srivastava Shiv , Sesterhenn Isabell A.
Published: February 2011

Introduction: Prevalent gene fusions involving regulatory sequences of the androgen receptor (AR) regulated prostate associated genes (predominantly TMPRSS2) and protein coding sequences of nuclear transcription factors in the ETS gene family (primarily ERG), result in frequent overexpression of ERG in prostate tumors. Emerging studies suggest oncogenic functions of ERG in prostate cancer (CaP). Despite numerous reports of gene fusions and mRNA expression, ERG oncoprotein in CaP still remains to be defined. Using an anti-ERG monoclonal antibody (ERG-MAb) developed by our group, a global view of ERG oncoprotein expression has been established in the context of multi-focal CaP.

Experimental procedures: Specificity of the ERG MAb was established using wt ERG and TMPRRSS2-ERG encoded proteins expressed in HEK 293 cells and ERG si RNA treated VCaP cells harboring TMPRRSS2-ERG fusion. ERG expression in formalin fixed paraffin embedded (FFPE), whole mount-prostate specimens was optimized by immuno-histochemistry assay. TMPRSS2-ERG fusion status in representative specimens was analyzed by b-DNA assay or fluorescent in situ hybridization (FISH).

Results: Through exhaustive evaluations of 132 whole-mount prostates (227 tumor foci and over 200,000 benign glands), we demonstrate 99.9 % specificity of an anti-ERG monoclonal antibody. Specimens from over 60% patients had one or more ERG positive tumor focus. Over 80% concordance was noted between the presence of ERG protein and the common TMPRSS2-ERG fusion (A type) transcript in representative specimens from 35 pateints.

Conclusions: Unequivocal association of focally ERG positive PIN lesions with ERG positive carcinoma (80 out of 80 specimens) and vice versa (52 out of 52 specimens) strongly affirms biological role of ERG in clonal progression of prostate tumors. Taken together, the homogeneous and strong ERG expression in individual tumors establishes the potential for ERG based stratification of prostate cancers.

Funding sources: NIH Grants RO1 DK065977 and Center for Prostate Disease Research Program HU001-04-C-1502

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 30.
Abstract 300: Regulation of androgen receptor transactivity and mTOR-S6 kinase pathway by Rheb in prostate cancer cell proliferation
Authors: Kobayashi Takashi , Inoue Takahiro , Shimizu Yosuke , Terada Naoki , Yamasaki Toshinari , Nakamura Eijiro , Toda Yoshinobu , Nishiyama Hiroyuki , Kamoto Toshiyuki , Ogawa Osamu
Published: February 2011

Ras homolog-enriched in brain (Rheb), a small GTP-binding protein, is associated with prostate carcinogenesis through activating mammalian target of rapamycin (mTOR) signaling pathway. This study aimed to elucidate whether Rheb promotes proliferation of prostate cancer cells and can act as a potent therapeutic target in prostate cancer. Rheb mRNA and protein expression was higher in more aggressive, androgen-independent prostate cancer cell lines PC3, DU145 and C4-2, compared with the less aggressive LNCaP. Rheb expression was higher in human prostate cancer tissues than in benign prostatic epithelia. Forced expression of Rheb in LNCaP cells accelerated proliferation without enhancing androgen receptor transactivity. Attenuation of Rheb expression or treatment with the mTOR inhibitor rapamycin decreased proliferation of PC3 and DU145 cells, with a decrease in the activated form of p70S6 kinase, one of the main targets of mTOR. Rheb potentiates proliferation of prostate cancer cells and inhibition of Rheb or mTOR can lead to suppressed proliferation of aggressive prostate cancer cell lines in vitro. Rheb and the mTOR pathway are therefore probable targets for suppressing prostate cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 300.