bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 114: Study of the high-grade ovarian cancer precursors in the oviduct
Authors: Hwang In Young , Yuan Ju , Ning Gang , Tay Seok Wei , Yamamoto Yusuke , Menghi Francesca , Liu Edison , Crum Christopher P. , McKeon Frank , Xian Wa
Published: August 2012

The discovery that many high-grade ovarian cancers originate in the oviduct has generated a paradigm shift in the field of ovarian cancer. The description of new entities in the oviduct that signify early phases of ovarian carcinogenesis, including both serous tubal intraepithelial carcinomas and their precursors the p53 signatures, has provided a tangible sequence of events leading to malignancy that can be linked to DNA damage and p53 mutations. However, it has become clear that other pathway disturbances also play a critical role in the early development of ovarian cancer. We hypothesize that molecular alterations present in morphologically normal oviductal epithelium from ovarian cancer patients reflect the earliest events in ovarian carcinogenesis and may be markers of increased cancer risk as well as targets for risk reduction. Whole-genome transcriptome analysis of laser microdissected oviductal epithelium from histologically normal ovarian cancer patients and controls was performed. We identified a set of aberrantly expressed genes in the oviductal epithelium from women who developed high-grade ovarian cancer and demonstrated some of these genes are also abnormally expressed in the ovarian cancers due to the genomic alterations. We further examined the function of these genes using three-dimensional cell culture system and mouse models. Our work demonstrates the synergistic effects of defective p53 pathway and other newly found pathways in driving early steps of ovarian cancer development.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 114. doi:1538-7445.AM2012-114
Abstract 1141: Telomerase activity in relation to RET mutation status in medullary thyroid carcinoma
Authors: Wang Na , Zedenius Jan , Bäckdahl Martin , Larsson Catharina
Published: August 2012

Background: Medullary thyroid carcinoma (MTC) originates from parafollicular C cells of the thyroid gland, and are associated with activating constitutional or somatic mutations in the RET proto-oncogene. The common somatic mutation of codon 918 is associated with a less favorable clinical outcome. The catalytic component of telomerase, human telomerase reverse transcriptase (TERT) has been found to be reactivated in most human tumors. Objective: In this study, we aimed to investigate telomerase involvement in relation the RET mutational status in MTC. Design: Our study includes 43 cases of MTC from the Karolinska University Hospital. RET mutations were identified by sequencing of the hot spots in exons 10,_11-,_15-, and 16. Expression of the TERT gene, telomerase activity and telomere length were quantified. Result: Among the 43 cases, 18 carried a RET point mutation in exon15 or exon16 (Group I), 5/43 had a point mutation in exon 10 or 11 (Group II), and 20 were wild-type (Group III). Telomerase activity and TERT expression were closely associated. The TERT gene was expressed in 13/18 cases in Group I, in 0/5 in Group II and in 10/20 of Group III. The median telomerase activity was higher in Group I as compared to Groups II and III. Group I tumors showed the shortest relative telomere length. With regard to follow-up, cases with high telomerase activity and TERT gene expression in Group I had less favorable outcome. Conclusion: The findings suggest that TERT/telomerase activity may contribute to aggressive MTC in addition to, or as a consequence of, RET codon 918 mutations. The very low telomerase activity and TERT expression revealed in several of the MTC cases suggest the involvement of alternative mechanisms for telomere stabilization in the MTC entity.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1141. doi:1538-7445.AM2012-1141
Abstract 1143: EZH2 promotes oral squamous cell carcinoma initiation and progression through epigenetic silencing of FHL1
Authors: Cao Wei , Chen Wantao
Published: August 2012

Oral squamous cell carcinoma (OSCC) is widely represented as a heterogeneous tumor with more aggressive phenotypes, but the basis for these characteristics remains unknown. In the current study, we show that up-regulation of the Polycomb complex histone methytransferase EZH2 is critical to maintain the malignant phenotypes in OSCC and associated significantly with oral squamous cell carcinoma development in patients with oral leukoplakia (OLP), which represents oral precancerous lesion as well as the worse prognosis of patients with locally advanced OSCC. Patients with OLP (n=76) and OSCC (n=124) from two independent cohort were included in this study. Immunohistochemical analyses on EZH2 in the two cohort revealed that the higher EZH2 levels were strongly associated with dysplasia (P < 0.001) and OSCC development (P < 0.0001) in patients with OLP, as well as worse overall survival (P = 0.001) and disease free survival (P = 0.002) in patients with locally advanced OSCC. Furthermore, upon EZH2 silencing by small interfering RNA (siRNA)-mediated knockdown, the proliferation, anchorage-independent growth and invasion potential of OLP cell line and OSCC cell lines were remarkably suppressed. Available publicly H3K27 modifications based on CpG array and three public microarray datasets (GEO) analyses identified human four-and-half LIM protein 1(FHL1) as a novel candidate target of EZH2 in OSCC. Further depletion of EZH2 by RNA interference (RNAi), the expression of FHL1 was notably restored in OLP and OSCC cell lines. In addition, ablation of FHL1 by RNA interference promoted significantly proliferation and invasion potential of OSCC cells. Together, our findings indicate that aberrantly elevated EZH2 promotes aggressive phenotypes of OLP and OSCC cells and plays a critical role in initiation and progression of OSCC. meanwhile, FHL1 may be a novel target of EZH2 for transcriptional repression in OSCC initiation and progression. ACKNOWLEDGMENTS: This study was supported by the National Natural Science Foundation of China (Grant No. 30973343), Projects of the Shanghai Science and Technology Committee (Grant No. 08JC1414400 and 10XD1402500) and the Shanghai Leading Academic Discipline Project (S30206).

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1143. doi:1538-7445.AM2012-1143
Abstract 1145: Molecular markers of neoadjuvant chemotherapy and combined chemoradiotherapy response in patients with oropharynx squamous cell carcinoma
Authors: Hatakeyama Marcia , Reis-Rosa Luciana A. , Marchi Fábio A. , Spilborghs Graziela , Carvalho André L. , Nicolau Ulisses R. , Kowalski Luiz P. , Rogatto Silvia R.
Published: August 2012

The treatment currently considered standard for advanced oropharyngeal tumors involves concomitant chemo- and radiotherapy or surgery followed by adjuvant chemo- and radiotherapy. However, only 30 to 50% of patients with locally advanced disease survive more than three years, even with the advances in surgical techniques and the recognized benefits of therapy combined with radio- and chemotherapy. Treatment with induction TPF (docetaxel plus cisplatin and fluorouracil) chemotherapy followed by chemoradiotherapy was associated with a trend toward improved survival (Posner et al., 2007. N Engl J Med. 357:1705). The aim of this study was to investigate biological markers as potential predictors of response to chemotherapy and/or radiotherapy according to HPV infection in oropharyngeal carcinomas (OC). Thirty-two OC were evaluated by array CGH (4x180k, Agilent). A total of 35% of cases were HPV positives; HPV16 subtype was the most frequently detected (8/37), followed by subtype 18 (2/37). In general, HPV- cases showed a large number of copy number alterations (117 CNAs) in comparison with HPV+ samples. Losses on 7q22.1 and 14q12 were found exclusively in HPV+ tumors (p=0.044). Comparative analysis of genomic alterations among the patients which received combined chemoradiotherapy (22 cases) was done aiming to identify molecular markers that could predict the complete response (CR), partial response (PR) to treatment or progressive disease (PD). Tumors with CR showed a lower number of genomic alterations (90 CNAs versus 110 per cases in PR and PD). Losses at 1p21.3-p21.1 and gains on 10p13-p12.33 and 10p12.31-p12.1(p≤0.017) were exclusively found in patients with PD and PR. Overall survival (OS) analysis between HPV- and HPV+ cases demonstrated no significant differences (p>0.05). HPV- tumors showed more complexity and genomic instability than HPV+ tumors. Genomic losses or gains at different loci have been reported in HPV- compared to few or no alterations in HPV+ cases. In this study, it was detected specific chromosomal imbalances associated with therapy response and consequently, putative candidates to be validated in a large series of cases.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1145. doi:1538-7445.AM2012-1145
Abstract 1148: The relationship between the EMT status in primary lung adenocarcinomas and the DFS, and the results of the molecular analyses of lung adenocarcinoma with regard to the IGF1R and EMT status
Authors: Chikaishi Yasuhiro , Uramoto Hidetaka , Takenaka Masaru , Oka Soichi , Nakagawa Makoto , Shimokawa Hidehiko , So Tomoko , Hanagiri Takeshi , Tanaka Fumihiro
Published: August 2012

Background: Predicting the risk of distant micrometastasis of NSCLC after complete surgical resection is a significant problem to solve, and useful molecular markers that can predict recurrence have not yet been identified. The epithelial to mesenchymal transition (EMT) is an important contributor to the invasion and metastasis of epithelial-derived cancer. However, there is currently no data about the EMT status in primary NSCLC and its clinical usefulness to predict the recurrence and disease free survival (DFS). In addition, an association between insulin-like growth factor 1 (IGF1) and EMT-related molecules was reported, therefore, we also analyzed the association between the expression of IGF1R and EMT-related molecules. Methods: Tumor specimens were collected from 182 consecutive patients who underwent a complete resection for lung adenocarcinoma from 2003 to 2007 in our department. We analyzed the expression levels of EMT-related molecules (E-cadherin, gamma catenin and vimentin) in the primary lung adenocarcinoma by immunohistochemisty. We also analyzed the association between the expression of IGF1R and EMT-related molecules in the primary lung adenocarcinoma by immunohistochemisty. Results: The positive expression of E-cadherin, gamma catenin and vimentin was identified in 94 (51.4%), 82 (40.4%) and 32 (17.5%) patients, respectively. Their expression was not correlated with recurrence or disease-free survival (DFS) according to the survival analysis. Positive expression of IGF1R was detected in 43 (23.6%) patients, and its expression was significantly associated with the expression of E-cadherin and gamma-catenin, but not with vimentin.Conclusions: The EMT status in the primary tumor of NSCLC does not predict the recurrence and disease free survival. However, there was a significant association between the expression of IGF1R and several EMT-related proteins in patients with lung adenocarcinoma.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1148. doi:1538-7445.AM2012-1148
Abstract 1154: Genetic variation in NFκB signaling pathway genes in colorectal cancer susceptibility and survival
Authors: Ungerbäck Jonas , Belenki Dimitri , Fredrikson Mats , Elander Nils , Verma Deepti , Söderkvist Peter
Published: August 2012

PURPOSE: Genetic alterations in inflammatory genes are associated with chronic inflammatory bowel disease, a well-known risk factor for colorectal cancer (CRC). The purpose of this study was to investigate the association between alterations in inflammatory NFκB signaling pathway genes and CRC susceptibility and survival. EXPERIMENTAL DESIGN: Using 344 CRC cases and 793 randomly selected healthy individuals from southeastern Sweden, we examined seven polymorphisms in NFκB, TNFAIP3, NLRP3, CARD8 and TLR4 genes. Chi-square tests and multiple logistic regression analysis were used to test for associations between the SNPs and CRC susceptibility, while log-rank tests and Cox proportional hazard regression were used to examine the association between the SNPs and CRC-specific survival. Loss of heterozygosity and mutational analyses of TNFAIP3 were carried out in 137 and 79 tumors, respectively. RESULTS: Adjusted for age, gender and polypoid/ulcerative CRC phenotype, a panel of heterozygous and mutant TNFAIP3 (rs6920220), mutant NF B −94 ATTG ins/del and heterozygous NLRP3 (Q705K) was associated with poorer survival in patients diagnosed with invasive CRC (aHR = 5.2 95% CI 2.5-10.9, P < 0.001). Continuous or partial LOH of 6q23.3, the location of the TNFAIP3 gene was detected in 17% of the colorectal tumors while mutations in TNFAIP3 were detected in two out of 79 colorectal tumors (2.5%). CONCLUSIONS: We propose TNFAIP3 as a novel tumor suppressor in CRC and also present evidence that a panel of the TNFAIP3 (rs6920220), NF B −94 ATTG ins/del and NLRP3 (Q705K) polymorphisms could be used as a prognostic marker to identify patients at high risk for rapid CRC progression and poor survival.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1154. doi:1538-7445.AM2012-1154
Abstract 1159: Differential expression of BP1 and associated gene networks in breast cancer of African American women and Caucasian American women
Authors: Nguyen Thuan H. , Berg Patricia E. , Ghimbovschi Svetlana , Grizzle William E.
Published: August 2012

Introduction: BP1 is a transcription factor of the homeobox gene family activated in 89% of the tumors of African American women (AAW) compared with 57% of the tumors of Caucasian American women (CAW). AAW with breast cancer have larger tumors and an almost 50% higher mortality rate than CAW. BP1 expression is also associated with larger and more aggressive tumors, suggesting BP1 may contribute to the aggressiveness of tumors of AAW. Importantly, BP1 appears to be involved in the epithelial to mesenchymal transition (EMT), based on (i) activation of Twist, a trigger of EMT, (ii) decreased expression of epithelial markers, and (iii) increased expression of mesenchymal markers in cells engineered to overexpress BP1; EMT can lead to metastasis. Here we set out to identify molecular pathways underlying the discrepancy of breast cancer aggressiveness in AAW and CAW with particular attention to BP1 regulated pathways. Results: Cell line analysis. We analyzed five cell lines derived from tumors of AAW and five derived from CAW for EMT markers, including E-CADHERIN (epithelial) and VIMENTIN (mesenchymal). Interestingly, in both types of cell lines, two were epithelial, one was mesenchymal, and two were not classifiable. Two of the AAW derived cell lines and three of the CAW derived cell lines were further studied using microarrays. Preliminary analysis revealed that MYC, CASPASE3, and PPARG are overly represented in the cell lines derived from AAW compared to their CAW derived counterparts; these cell lines also overexpress BP1. Further studies will be performed to determine other pathways that may be differentially expressed in the cell lines from AAW and to determine whether BP1 regulates those pathways. Clinical studies. Tumor tissues from AAW and CAW, matched for age and stage of breast cancer, will be immunostained to determine differential expression of BP1 and EMT markers, and genes identified by microarray analysis as being regulated by BP1. Localization studies of BP1 protein revealed that the nuclear membrane stained most intensely for BP1, with nucleus > cellular membrane > cytoplasm staining. Nuclear and cytoplasmic staining for BP1 tended to be less for CAW than AAW. Conclusions: Our data identify several molecular pathways that may be preferentially activated in breast cancer of AAW. Genes that are overexpressed in tumors of AAW compared with tumors of CAW would make good targets for therapy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1159. doi:1538-7445.AM2012-1159
Abstract 1166: PTEN loss and ERG over-expression as prognostic biomarkers in prostate cancer and identification of downstream biomarkers with potential therapeutic value
Authors: Williams Julia L. , Yoshimoto Maisa , Nuin Paulo , Greer Peter A. , Squire Jeremy A.
Published: August 2012

Genomic deletion of the PTEN tumor suppressor gene and formation of the TMPRSS2:ERG gene fusion are the two most recurrent genomic aberrations in prostate cancer. The lipid phosphatase activity of PTEN negatively regulates the PI3Kinase-AKT signaling pathway, which controls numerous downstream targets such as cell cycle checkpoints, DNA damage repair with maintenance of chromosomal stability and integrity. ERG is a member of the ETS transcription factor family, whose members are implicated in numerous cellular processes including membrane remodelling, angiogenesis, differentiation, proliferation, and tumourigenesis. Emerging evidence suggests that formation of the fusion gene may promote prostatic tumourigenesis, progression, and invasive disease by elevating motility and invasiveness. The simultaneous manifestation of both PTEN loss and TMPRSS2:ERG fusion is associated with poor prognosis. This study is addressing pathways downstream of PTEN and effectors of ERG over-expression to identify additional biomarkers of prognostic and therapeutic potential. In silico genomic copy number analyses demonstrated that patient samples harboring a genomic deletion of PTEN have a greater number of genomic aberrations, in keeping with the model that loss of PTEN leads to heightened genomic instability. Mining of publically available gene expression datasets have been performed to further examine signalling pathway aberrations specific to each rearrangement. PTEN loss and ERG over-expression are being modeled in the histologically normal prostate epithelial cell line RWPE-1 using shRNA knockdown or transgene directed ectopic over-expression, respectively. Biochemical, proliferation, migration and invasion assays will be performed to determine if knockdown of PTEN leads to the expected AKT activation and increased proliferation; whereas over-expression of ERG in RWPE-1 cells correlates with heightened motility and invasive potential. Gene expression microarray profiling will also be carried out for each derivative RWPE-1 cell line using the Agilent SurePrint G3 Human Exon microarrays. This cell model system will be used to validate transcriptional changes associated with PTEN loss and ERG over-expression in prostate cancer gene expression datasets and identify potential novel downstream therapeutic targets and predictive biomarkers.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1166. doi:1538-7445.AM2012-1166
Abstract 1168: Identification of CNA signatures in prostate cancer: Narrowing chromosome regions related with occurrence, prognosis and recurrence after treatment
Authors: Rodrigues Tatiane C. , Carvalho Felipe , Krepischi Ana C. V. , Verjovski-Almeida Sergio , Rosenberg Carla
Published: August 2012

Prostate cancer is the most common cancer in males and, despite its high incidence, only limited data are available on which genes or chromosome regions are specifically involved in its initiation and progression. We studied 72 prostate tumor samples by array-CGH, using a platform containing 60.000 oligonucleotides spread over the whole genome (60K Agilent Technologies). No chromosome alterations (CNA) were detected in 13 samples. The array-CGH profiles of the remaining samples showed losses at 8p and gains on 8q, often with narrow peaks of amplification, in ∼50% of the tumors. Additionally, losses at 6q, 13q and 16q were observed in ∼25% of the samples. Although these results are in general agreement with the location of alterations described earlier, the altered chromosome segments are often several megabases long. Mapping of minimum regions altered in several tumors, or pronounced copy number changes in smaller segments, permits a more precise definition of the relevant chromosome regions that are relevant for tumor development and progression. Current prognostic variables include prostatic specific antigen (PSA), the pathologically defined Gleason score (GS) and T-category (of the TNM staging). There is a great heterogeneity within the intermediate risk group and further genetic markers are needed to refine disease diagnosis and prognosis. So, we analyzed the copy number alteration signatures for the intermediate risk group, Gleason 7. In the comparison between samples related as GS 6 versus GS 7, we found that losses on 5q21.1 and gains on 7q11.21 are more frequent in GS 7. In other hand, losses on 22q13.33 are more frequent in GS 7 than in GS 8 and 9, while losses on 6q21 and 18q21 are correlated with GS 8 and 9. Additionally, we have medical follow-up of only 46 of the 72 samples. Fifteen of these patients had present recurrence after treatment. We analyzed this group versus the group with no recurrence. Losses at 2p21, 6q12, 7q36.3 and 16q13 are more frequent in the group of patients in which there is recurrence of the tumor. This suggests that these alterations could also be hallmarks for recurrence. Further studies with array-CGH of prostate tumors samples will ultimately lead to defining much smaller regions of overlap than at present, which in turn will indicate which specific individual genes and/or combinations of genes are the real “drivers” in prostate cancer or could act as hallmarks for prognosis and recurrence.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1168. doi:1538-7445.AM2012-1168
Abstract 1169: Non-canonical functions of Mdm2 isoforms in estrogen influenced breast cancer cells with wild-type or mutant p53
Authors: Bargonetti Jill , Okoro Danielle , Kundu Nandini , Brekman Angelika , Gao Chong , Rosso Melissa , Polotskaia Alla
Published: August 2012

Estrogen receptor positive breast cancers often have high levels of Mdm2. We investigated if estrogen signaling in breast cancers occurred through an Mdm2 mediated pathway. We examined the effect of long-term 17β-estradiol (E2) treatment in ERα positive breast cancer cell lines that contain wild-type p53 (MCF-7) and mutant p53 (T-47D). These cell lines also contain the mdm2 SNP at position 309, which increases the expression of Mdm2 by Sp1 driven transcription. In both these cell lines, we observed that E2 treatment dramatically increased the amount of Mdm2 without decreasing the corresponding wild-type or mutant p53. Surprising the amount of p53 protein in both cell lines increased with E2 treatment. We engineered miR30-based inducible mdm2 knockdown cell lines of MCF-7 and T-47D to evaluate to impact of Mdm2 on their cancer cell phenotypes. The down-regulation of Mdm2 in MCF-7.shmdm2 and T-47D.shmdm2 inhibited cell proliferation in 2D culture and in 3D laminin-rich matri-gel. Knockdown of Mdm2 did not cause an increase in p53 protein. These data suggest a p53-independent signal transduction pathway for Mdm2-mediated activation of proliferation. Alternative spliced mdm2 transcripts have been observed in many cancers including breast, but no endogenous protein isoforms from the spliced isoforms have been described. We asked if the spliced variant Mdm2-C transcript (that lacks most of the N-terminal p53 binding domain) expressed endogenous protein in these breast cancer cell lines. We created an Mdm2-C specific antibody using a synthetic peptide to the splice junction of exons four and ten (C4-10) to detect the protein. We validated the C4-10 antibody using in vitro translated Mdm2 compared to Mdm2-C. High expression of Mdm2-C occurred in the G/G mdm2 SNP309 ER+ breast cancer cell line T-47D, but only a slight increase was detected in the presence of E2. Additionally, Mdm2-C was found in nucleolar and cytoplasmic foci before and after estrogen treatment, while the mutant p53 was predominantly nuclear. We report the first identification of endogenous tumor-associated Mdm2-C protein in breast cancer. We suggest that Mdm2 and its isoforms work through non-canonical pathways to transform estrogen influenced breast cancers through molecular pathways that remain to be elucidated. Acknowledgements: This work was supported by Breast Cancer Research Foundation to J.B. and NSF grant to JB MCB-0744316. D.O. was also partially supported by a CUNY Graduate Center Magnet Award. Special thanks to Gerard Evan for help with immunogen peptide design.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1169. doi:1538-7445.AM2012-1169
Abstract 117: The processed pseudogene POU5F1P1in 8q24 is expressed in tumor and shows oncogenicity
Authors: Fang Jun
Published: August 2012

Genome-wide association studies (GWAS) have identified a segment of approximately 1 Mb of 8q24 as a multi-cancer cancer susceptibility region. The region is flanked by two genes, FAM84B and MYC, the latter an established oncogene. Within this region of 8q24, there is a processed pseudogene, POU5F1P1. We have re-sequenced the exon regions of wild type POU5F1 on chromosome 6 and its six counterpart pseudogenes on chromosomes 1, 3, 8, 10 and 12, and identified sequence variants unique to POU5F1P1 for which we have developed and confirmed analysis of expression of the POU5F1P1 transcript on 8q24. The homolog between wild type POU5F1 and pseudogene POU5F1P1 is about 97%. By using TaqMan DNA copy number variation assays, we identified uncommon copy number variants across this region. However, the DNA copy number variation does not contribute to differences in expression of POU5F1P1. Expression of POU5F1P1 was confirmed in a subset of the NCI60 panel using quantitative TaqMan real-time PCR assays in cell lines of colon, ovarian and breast cancers. Both POU5F1 and POU5F1P1were further evaluated in 14 colon cancer cell lines of which two, DLD-1 and KM12, expressed POU5F1P1 but no wild type POU5F1. Using shRNA technology (two constructs for each target), we knocked down POU5F1P1 expression in DLD-1 and KM12, which lead to reduction in the growth rate and anchorage-independent growth of colon cancer cells. Our results suggest that the processed pseudogene, POU5F1P1 is expressed in cell lines and colon cancer tissues. Moreover, preliminary studies suggest that its function could be related to oncogenic activity, though further studies are needed to verify this observation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 117. doi:1538-7445.AM2012-117
Abstract 1172: Prodigiosin and its structural analogue rescue deficient p53 pathway signaling and anti-tumor effects via p73 upregulation in p53 mutant and null colorectal cancer cells
Authors: Hong Bo , Dicker David T. , Kopelovich Levy , El-Deiry Wafik S.
Published: August 2012

The tumor suppressor p53 gene is mutated in over 50% of human cancers, and this is associated with resistance to radiotherapy and chemotherapy as well as tumor progression. Therefore, p53 pathway functional reactivation in p53-deficient cancers is an attractive strategy for cancer therapy and may address an unmet need in the clinic for progressive therapy-refractory human tumors. We previously showed that Prodigiosin and its structure analogue can reactivate the p53 pathway in p53 mutant and null colorectal cancer cells (Hong et al. AACR 2011, abstract 607). Here, we examined the mechanism of p53 pathway reactivation by Prodigiosin and its structural analogue in colorectal cancer cells. p73, a p53 family protein, shares a high degree of sequence homology with p53 and regulates the expression of similar genes by binding to p53 responsive elements within gene promoters and performs similar functions to p53. However, unlike p53, p73 is not a target for mutational inactivation in human cancer. In the study, we hypothesized that Prodigiosin and its structural analogue induce p73 expression to activate the p53 pathway and further induce cellular apoptosis in p53-deficient cancer cells. We showed that Prodigiosin and its structural analogue induced p73 expression in p53 mutant SW480 and p53−/− HCT116 cells. We also showed that the induction of p53-responsive transcriptional activities by Prodigiosin and its structural analogue was reduced in SW480 cells with p73 stable knockdown, as compared with parental SW480 cells. Western blot analysis indicated that the induction of a p53 target protein DR5 by Prodigiosin and its structural analogue was decreased in SW480 cells with p73 stable knockdown, as compared with parental SW480 cells. The sub-G1 analysis demonstrated that Prodigiosin and its structural analogue induced less apoptosis in SW480 cells with p73 stable knockdown than parental SW480 cells. Together, these findings indicate that p73 upregulation is involved in the mechanism of p53 pathway activation and apoptotic induction by Prodigiosin and its structural analogue. The study suggests that p73 induction may be a useful alternative way to reactivate p53 pathway in p53 mutant and null cancer cells and provides important mechanistic insights into the activity of a potent p53 pathway function restoring small molecule that is a candidate therapeutic for human cancer. This work was supported by the NCI Developmental Therapeutics Program through NCI Contract N01-CN-43302.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1172. doi:1538-7445.AM2012-1172
Abstract 1173: AKT-mTOR pathway mediates mutant p53 gain-of-function by inhibiting autophagy
Authors: Guo Xiaolan , Zhao Liyan , Xiong Hua , Auringer Kyle , Wang Lei , Deng Yibin
Published: August 2012

Nearly half of human cancers harbor p53 mutations, which are predominantly through missense mutations that result in accumulation of mutant p53 proteins in cancer cells. Persistent evidence supports that the mutant p53 proteins not only lose tumor suppressor activity, but also acquire gain-of-function abilities to promote carcinogenesis, metastasis, tumor recurrence and chemoresistance. Indeed, knock-in mouse models bearing the mutant p53R172H (equivalent to human R175H mutation) at physiological level in vivo display gain-of-function phenotypes, such as enhanced cell transformation potentials and tumor metastasis. However, the molecular mechanism of mutated p53R172H conferring gain-of-function remains poorly understood. In this study, utilizing mouse embryonic fibroblasts (MEFs) and lung adenocarcinoma cells (93-1) derived from p53R172H knock-in mice, we observed that AKT was preferentially activated in p53R172H mutant cells over p53-deficient cells. This activation of AKT allows p53R172H mutant cells to bypass contact inhibition, grow in an anchorage-independent manner and form tumors after subcutaneous injection into SCID mice. In contrast, expression of dominant negative AKT or shRNA-mediated AKT knockdown in p53R172H mutant cells inhibited colony formation in soft-agar and suppressed tumor growth in mouse xenograft tumor model. To directly dissect the essential role of AKT in p53R172H mutant-initiated tumorigenesis in vivo, we bred AKT1 knockout mice to p53R172H mutant knock-in mice. Loss of AKT1 significantly reduced the incidence of tumor development and extended the life span from around 3 months in AKT1-proficient and p53R172H mutant mice (AKT1+/+; p53R172H/R172H) to about 12 months in AKT1-deficient and p53R172H mutant mice (AKT1−/−; p53R172H/R172H). To understand how the activated AKT conferred mutant p53 gain-of-function, we demonstrated that p53R172H mutant activated AKT-mTOR signaling pathway that led to an inhibition of autophagy both in vitro and in vivo. Furthermore, induction of autophagy in p53R172H mutant lung cancer cells through suppressing AKT-mTOR pathway pharmacologically by the dual kinase inhibitor NVP-BEZ235 treatment or genetically by RNAi-mediated knockdown of mTOR dramatically inhibited p53R172H mutant-induced colony formation in soft agar and tumor growth in SCID mice. Our results support that AKT plays a crucial role in mediating mutant p53 gain-of-function phenotypes in vivo through the inhibition of autophagy by the activated AKT-mTOR signaling pathway. These findings provide the proof-of-principle that targeting the AKT-mTOR-autophagy pathway might have promising therapeutic benefits for cancer patients carrying such p53 mutations.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1173. doi:1538-7445.AM2012-1173
Abstract 1174: ASPP2: Tumor suppression through the control of polarity and proliferation
Authors: Lu Xin
Published: August 2012

Cell polarity and proliferation are processes that play key roles in development. Loss of cell polarity and increased cellular proliferation are hallmarks of human cancer. The identification of molecules that are involved in the control of these processes is, therefore, important for our better understanding of tumor development and progression. p53 was recently found to be important in controlling the mammary epithelial stem cell pool. We have recently shown that ASPP2, a regulator of p53 and binding partner of many other proteins including YAP, is an important player in the regulation of cell polarity due to its ability to bind and regulate Par-3. Interestingly, ASPP2 is also able to directly regulate cell proliferation by affecting the activity of cyclin D1, by inhibiting the nuclear localisation of SUMO-modified cyclin D1. As ASPP2 is a haploinsufficient tumor suppressor, these findings identify ASPP2 as a unique regulator of cell polarity: able to influence cell polarity on the one hand and the cell cycle machinery on the other. ASPP2's interactions with p53, YAP and others, along with its potential role in controlling cell migration and EMT will be discussed. References Samuels-Lev Y, O'Connor DJ, Bergamaschi et al. ASPP proteins specifically stimulate the apoptotic function of p53. Mol Cell. 2001 Oct;8(4):781-94. Vives V, Su J, Zhong S, Ratnayaka I, Slee E, Goldin R, Lu X. ASPP2 is a haploinsufficient tumor suppressor that cooperates with p53 to suppress tumor growth. Genes Dev. 2006 May 15;20(10):1262-7. Sottocornola R, Royer C, Vives V et al. ASPP2 binds Par-3 and controls the polarity and proliferation of neural progenitors during CNS development. Dev Cell. 2010 Jul 20;19(1):126-37. Epub 2010 Jul 8. Wang XD, Lapi E, Sullivan A, Ratnayaka I, Goldin R, Hay R, Lu X. SUMO-modified nuclear cyclin D1 bypasses Ras-induced senescence. Cell Death Differ. 2011 Feb;18(2):304-14. Epub 2010 Aug 27.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1174. doi:1538-7445.AM2012-1174
Abstract 1175: The tumor-associated p53 R172H mutation does not display gain-of-function properties in hepatocellular carcinoma
Authors: Ahronian Leanne G. , Lewis Brian C.
Published: August 2012

Hepatocellular carcinoma is a highly deadly malignancy, accounting for approximately 600,000 deaths worldwide every year. A common genetic change in HCC, present in 30% of cases, is mutation of the p53 tumor suppressor gene. p53R175H (corresponding to R172H in mice) is a hotspot for mutation that demonstrates “prometastatic” gain-of-function in pancreatic cancer. Since the frequency of p53 mutation increases with tumor grade in HCC, we hypothesized that p53R172H is a gain-of-function mutation in HCC that contributes to an increase in metastasis and a decrease in tumor-free survival. To study the role of p53 mutation in HCC, we used the RCAS-TVA mouse model. Albumin-TVA, p53LSL-R172H/fl, Albumin-cre mice were crossed to Albumin-TVA, p53fl/fl, Albumin-cre mice to generate litters in which half of the progeny are p53fl/fl and half are p53R172H/fl. Injection of these litters with DF1 chicken fibroblasts producing RCAS viruses encoding the mouse polyoma virus middle T antigen (PyMT), resulted in specific infection and expression of PyMT in the liver. We found that p53R172H/fl mice did not have increased tumor incidence, nor did they display increased rates of metastasis, relative to p53fl/fl mice, suggesting that mutant p53 does not display gain-of-function properties during HCC development in vivo. Interestingly, while shRNA-mediated knockdown of p53 in R172H expressing HCC cell lines resulted in decreased cell migration, suggestive of gain-of-function properties, analysis of a panel of HCC cell lines from p53 null and R172H expressing tumors found no differences in anchorage-independent growth and cell migration between the two groups. Thus, although p53R172H expressing HCC cells depend on this mutant for their transformation, p53 mutant cells and tumors do not have enhanced properties relative to p53 null HCC cells and tumors. These data suggest that important pathway(s) impacted by mutant p53 are inhibited by alternate mechanisms in p53 null cells resulting in equivalent phenotypes. Interestingly, cell lines derived from HCCs with conditional p53 deletion exhibit decreased levels of a p63 isoform compared to cells from p53R172H mice. Since p53 mutants have been previously shown to bind and inhibit p63, reduced p63 expression in p53 deficient HCC cells may explain this observation. Elucidation of the role of p63 in regulating HCC migration and metastasis is currently underway.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1175. doi:1538-7445.AM2012-1175
Abstract 1179: 15-PGDH inhibits cholangiocarcinogenesis through the induction of TAp63
Authors: Lu Dongdong , Han Chang , Wu Tong
Published: August 2012

NAD+-linked 15-hydroxyprostaglandin dehydrogenase (15-PGDH) is responsible for the catabolism of prostaglandins in a variety of cell types such as inflammation an dtumorigenesis. In this study we showed that forced overexpression of 15-PGDH in human cholangiocarcinoma cells (CCLP1) suppressed tumor cell growth, invasion and clonogenic formation capacity. In contrast, 15-PGDH knockdown in CCLP1 cells enhanced tumor cell growth, invasion and clonogenic formation. Flow cytometry analysis revealed that 15-PGDH overexpression induced cell cycle arrest at G1/S checkpoint. When implanted into SCID mice, 15-PGDH overexpressed CCLP1 cells formed smaller xenograft tumors, whereas 15-PGDH-depleted cells formed larger xenograft tumors when compared with each of the corresponding controls (p<0.01). In addition, intratumoral injection of an adenoviral vector expressing 15-PGDH (pAd-15-PGDH) significantly inhibited the growth of cholangiocarcinoima in SCID mice. Western blot analysis showed that 15-PGDH induced the expression of TAp63, a key tumor suppressive gene. Furthermore, 15-PGDH induced the phosphorylation of Smad2/3 and enhanced the interaction between p53 and pSmad2/3 in CCLP1 cells; the pSmad2/3 and p53 binding complex appeared to play a key role for the induction of TAp63 expression. Taken together, our data suggest that 15-PGDH inhibits cholangiocarcinoma growth and this effect is at least in part through pSmad2/3 and p53-mediated induction of TAp63.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1179. doi:1538-7445.AM2012-1179
Abstract 1180: Modulation of p73 isoform expression regulates aggressive behavior in NHL cell line model with 1p36 chromosomal disruption
Authors: Hassan Hesham M. , Varney Michelle L. , Joshi Shantaram S. , Singh Rakesh K. , Dave Bhavana J.
Published: August 2012

Abnormalities of chromosome 1p36 locus are frequently detected in non Hodgkin lymphoma (NHL) and are associated with aggressive clinical behavior. TP73, a gene at 1p36 locus, is a member of the p53 tumor suppressor gene family, and regulates many important cellular pathways. TP73 gene function is controlled by a balance between two isoforms with opposing functions, the full length TAp73 protein (pro-apoptotic) and the NH2-terminally truncated ΔNp73 protein (anti-apoptotic through antagonizing both TAp73 and p53). Our previous work on diagnostic specimens of NHL cases had shown a differential ΔNp73 up-regulation and increase in ΔNp73:TAp73 expression ratio among NHL cases with 1p36 chromosomal disruption as compared to NHL cases without 1p36 disruption, which correlates with decreased apoptosis, increased cellular proliferation and increased angiogenesis. We hypothesized that modulated expression of the p73 isoforms will alter the aggressive behavior of a NHL cell line containing 1p36 disruption. We used a NHL cell line (Granta-519) that has 1p36 disruption as a model. Granta-519 cells express higher levels of ΔNp73 isoform similar to what was observed in NHL cases with 1p36 abnormality. Next, we stably transfected Granta-519 with a TAp73 mammalian expression vector to modulate the ΔNp73:TAp73 ratio. Cell cycle analysis showed an increase in the percentage of G1 cells and decrease in the percentage of S and G2 cells in TAp73-trasnfected Granta-519 cells as compared to control vector-transfected cells. Serum deprivation significantly inhibited the growth of Granta-519-TAp73- cells as compared to control vector-transfected cells. Moreover, reconstitution of TAp73 expression in Granta-519 cells significantly enhanced their response to Doxorubicin. Together, these results provide an insight on modulation of ΔNp73:TAp73 as a novel therapeutic target in NHL with 1p36 abnormalities.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1180. doi:1538-7445.AM2012-1180
Abstract 1184: The circadian factor Period2 modulates p53 function in unstressed cells
Authors: Finkielstein Carla V. , Gotoh Tetsuya , Vila-Caballer Marian , Santos Carlo , Liu Jingjing , Yang Jianhua
Published: August 2012

Circadian rhythms are mechanisms that measure time on a scale of about 24 h and that adjusts our body to external environmental signals. Core circadian clock genes are defined as genes whose protein products are necessary components for the generation and regulation of circadian rhythms. Circadian proteins also regulate genes involved in either cell division or death; and a perturbation of the balance among these processes leads to cancer development and progression. A key aspect of cancer research is identifying new regulatory pathways involved in proliferation and differentiation of cell. Disruption of circadian rhythm has recently emerged as a new potential risk factor in the development of cancer, pointing to the core gene period 2 (per2) as a tumor suppressor. However, it remains unclear how the circadian network regulates tumor suppression, nor which, if any, of its components is either the ultimate effector that influences the fate of the cell. Initial experiments were devoted to identify new interacting partners for Per2 using a two-hybrid system. Interestingly, among the positive clones analyzed was the tumor suppressor protein p53. This result was validated by immunoprecipitation of recombinant and endogenous Per2/p53 complexes from unstressed cells. Pull-down assays using tagged-expressed proteins fragments and labeled proteins were later used to map the interacting regions between Per2 and p53. Our results show Per2 binds to the C-terminus of p53 in a region that includes the DNA binding and tetramerization domains and that includes the ubiquitination sites. Thus, we hypothesized that binding of Per2 to p53 might act by blocking Mdm2-mediated ubiquitination of p53 target residues in the C-terminus and therefore altering its stability. We next examined the formation of the Mdm2/p53/Per2 complex by immunoprecipitation. Our data show anti-p53 antibody is able to co-immunoprecipitate Per2 and Mdm2. Moreover, in vitro and in vivo ubiquitination assays show that binding of Per2 to p53 prevented ubiquitination of p53 by Mdm2 without altering their binding. Immunofluorescence studies using H1299 cells (p53-) confirmed Per2 role in p53 stabilization and for localization. Overall our results suggest that Per2 modulates the stability of p53 in unstressed cells, and might be responsible for the oscillatory levels of p53 observed in a 24 h cycle.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1184. doi:1538-7445.AM2012-1184