bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 3065: Loss of ARL11 function promotes growth of in situ neoplasia by activating the ras pathway
Authors: Lee Sooyong , Lee Sangkyou , Bondaruk Jolanta , Wang Hua , Zhang Shizhen , Bar-Eli Menashe , Black Peter , Dinney Colin , Grossman H. Barton , Knowles Margaret , Baggerley Keith , Czerniak Bogdan
Published: February 2011

Our previously reported whole-organ genome-wide mapping studies of bladder cancer provided evidence that a new class of genes, referred to as forerunner (FR) genes (ITM2B, P2RY5, GPR38 and ARL11), located near known tumor suppressors such as RB1, may drive early clonal expansion of neoplasia. (S Lee, et al. PNAS 104: 13732-13737, 2007; T Majewski et al. Lab Inv 88: 694-712, 2008) These studies suggested three major steps for the involvement of the RB1 locus in tumor development. In the first step, one allele of FR gene and RB1 is inactivated by large deletions. In the second step, homozygous inactivation of the FR genes is accomplished by hypermethylation or less frequently by missence mutations. Homozygous inactivation of FR genes is associated with the clonal expansion of in situ lesions referred to as low-grade intraurothelial neoplasia. In the final, third step, the contiguous tumor suppressor, such as RB1, is inactivated most commonly by a mutation. This step is associated with clonal evolution into a transformed phenotype with microscopic features of carcinoma in situ progressing to invasive cancer. Recently, we concentrated our efforts on the ARL11 candidate FR gene, which encodes ADP-ribosylation factor-like 11 protein, a ras-related member of the small GTPases, that functions as GDP/GTP nucleotide interswitch for signal transduction. We have shown that it has been silenced by hypermethylation in approximately 40% of urothelial carcinomas of the bladder and the silencing was associated with in situ expansion of intraurothelial neoplasia. Moreover, loss of ARL11 expression was almost mutually exclusive with the FGFR3 mutations (<5% of bladder tumors showed a co-existence of mutant FGFR3 and methylated ARL11). Functional studies conducted on immortalized normal urothelial cells grown in vitro showed that ARL11 reduced cell proliferation, which was mediated by the inhibition of the ras pathway. This effect was associated with the down-regulation of the active ras and ERK1/2 phosphorylation as well as with the up-regulation of negative cell cycle regulator proteins such as p27kip1 and parallel down-regulation of cyclins D1 and E. Conversely, the silencing of ARL11 conferred a tumor suppressor effect promoting cell proliferation via the activation of the ras signaling pathway. In summary, our studies show that recessive events in the RB1 locus associated with the loss of ARL11 function promote clonal expansion of intraurothelial precursor lesions by activating the ras pathway in early occult phases of human bladder carcinogenesis.

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 3065.
Abstract 3070: CHFR, a potential tumor suppressor, downregulates interleukin-8 via inhibition of NF-κB
Authors: Tokino Takashi , Kashima Lisa , Toyota Minoru , Sasaki Yasushi
Published: February 2011

The mitoic checkpoint gene CHFR is silenced in various human cancers, suggesting that CHFR is a tumor suppressor. Here, we reveal that CHFR functions as a negative regulator of the NF-kB pathway. Expression of CHFR inhibited NF-kB reporter activity, while knockdown of CHFR activated reporter activity. These activities are independent of its RING finger domain. Further we found that CHFR interacts with p65 and negatively regulates transcriptional activity of p65. Moreover, our data demonstrate that IL-8 is significantly downregulated by CHFR and that the migration of human endothelial cells is suppressed in culture medium conditioned from CHFR-expressing cancer cells. Using a xenograft model, we show that angiogenesis is suppressed by adenovirus-mediated transfer of CHFR. These results indicate that expression of CHFR markedly reduces expression of IL-8 via the inhibition of NF-kB. Because the NF-kB plays a critical role in the development and progression of cancer, our finding demonstrate the functional relationship between epigenetic alteration and inflammation/antiogenesis in human cancer cells, thereby revealing several potential target for therapeutic intervention.

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 3070.
Abstract 3075: MUC4 mucin as a potential tumor suppressor in colon cancer
Authors: Das Srustidhar , Ponnusamy Moorthy Palanimuthu , Johansson Sonny L. , Senapati Shantibhusan , Pandey Poomy , Roy Hemant K. , Batra Surinder K.
Published: February 2011

MUC4 is a heterodimeric large transmembrane mucin expressed by several normal epithelial tissues like testis, lungs and colon and is aberrantly over expressed by most human adenocarcinomas. MUC4 has been strongly implicated to play the role of an oncogene in the progression and metastasis of pancreatic, breast and ovarian cancers. On the other hand, previous reports indicating the loss of MUC4 expression in the progression of colon cancer was starkly in contrast to the role it plays in other cancers. Based on the previous studies, we hypothesized that loss of MUC4 as the tumor progresses might act as a prognostic indicator and MUC4 might act as a potential tumor suppressor in the colon cancer. In the present study, our aim was to investigate the functional significance of MUC4 in colon cancer progression. We performed immunohistochemistry on a tissue microarray comparing the expression levels of MUC4 among normal colon, adenoma, adenocarcinoma and metastatic adenocarcinoma. MUC4 immunoreactivity was highest in the normal colon tissue and significantly higher than tubular adenoma, non-metastatic and metastatic adenocarcinoma (p<0.03) which confirmed the earlier findings. To evaluate the functional significance of MUC4, we stably over expressed MUC4 cDNA in HCT-15, a MUC4 non-expressing colon cancer cell line. Interestingly, the in vitro (growth kinetics, motility, invasion, colony forming) and in vivo (xenograft in nude mice) functional studies strongly support the role of MUC4 as a tumor suppressor in colon cancer. Further, mechanistic studies indicated that ectopic expression of MUC4 led to decreased activity of key intracellular signaling molecules like FAK, AKT and ERK. By regulating the levels of p-AKT, MUC4 expression led to growth arrest in S-phase which was mediated by the upregulation of cip/kip family of CDK inhibitors i.e. p21 and p27. Besides, overexpression of MUC4 led to a remarkable change from mesenchymal like (more triangular) phenotype to a more epithelioid (roundish) like phenotype confirmed by the phalloidin staining of the actin cytoskeleton. In conclusion, our results show for the first time the protective role MUC4 plays in colon 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 3075.
Abstract 3077: LARP7: Potential novel tumor suppressor gene in gastric cancer
Authors: Cheng Yulan , Jin Zhe , Montgomery Elizabeth , Agarwal Rachana , Yang Jian , Hamilton James , Selaru Florin , Olaru Alexandru , David Stefan , Abraham John M. , Stephen Meltzer J. , Mori Yuriko
Published: February 2011

Gastric cancer is one of the most deadly of all human tumors. However, little is known about events leading to this deadly disease. We previously reported that the RNA binding protein gene, La ribonucleoprotein domain family, member 7 (LARP7) was frequently subjected to genetic aberration in gastric cancers. LARP7 stabilizes the noncoding 7sk small nuclear RNA (7sk), and both LARP7 and 7sk compose 7sk snRNP that negatively regulates the positive transcription elongation factor b (P-TEFb). Hyperactive P-TEFb has been associated with hyper-proliferation and de-differentiation in various tissues. Therefore, the functional loss of LARP7 may contribute to gastric tumorigenesis. In the current study, we evaluated the involvement of LARP7 in human gastric cancer by assessing the LARP7 expression in normal and cancerous gastric tissues as well as by LARP7 knockdown in normal gastric epithelial cells. Methods: LARP7 expression was assessed by real-time quantitative RT-PCR in 30 normal and 25 cancerous gastric tissues. LARP7 knockdown was performed by the specific siRNA transient transfection in an immortalized normal human gastric epithelial cell line, HFE-145. Results: LARP7 mRNA expression was significantly decreased in gastric cancers compare to normal tissues (34.5% reduction, p<0.01). LARP7-targeting siRNA transfection in HFE-145 cells resulted in increased cell proliferation by 23% relative to the control siRNA transfection (p<0.05; measured by WST assay). We also observed a 28% decrease in 7sk quantity in LARP7-targeting siRNA transfectant relative to control siRNA transfectant (p<0.01). Conclusions: LARP7 downregulation is present in primary human gastric cancers and promotes 7sk downregulation as well as cell proliferation of normal gastric epithelial cells in vitro. Taken together, genetic aberrations that downregulate LARP7 may promote gastric tumorigenesis via p-TEFb deregulation. Further studies are warranted to explore the precise anti-tumor mechanisms of LARP7 and its potential role in the clinical care of 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 3077.
Abstract 3081: Loss of Shoca-2 expression in colorectal cancer correlates with metastasis as Shoca-2 represses EGF-regulated STAT3 activation via recruitment of PP1beta
Authors: Loeffler Sébastien , Kovac Michal , Zuklys Saulius , Keller Marcel , Hess Daniel , Piscuoglio Salvatore , Terraciano Luigi , Heinimann Karl , Holländer Georg
Published: February 2011

Objective: We sought to define in colorectal cancer (CRC) the function of Shoca-2 (a.k.a. SH2D4A), an until now uncharacterized SH2 domain-containing protein.

Methods: Tandem affinity purification, immunoprecipitation, site-specific mutagenesis, shRNA expression targeting and gene expression analysis were used to characterize binding partners of human Shoca-2 and identify the signaling pathway(s) where this adapter protein is involved. To assess Shoca-2 function on cell growth, colony formation assays and cell cycle analyses were carried out. CRC biopsies were analyzed by immunohistochemistry and molecular genetic methods for the presence of Shoca-2.

Results: Here we demonstrate that Shoca-2 forms a complex with EGFR and STAT3. In response to EGF signaling, a Shoca-2/STAT3 dimer dissociates from EGFR and recruits the serine/threonine phosphatase PP1beta to the complex. Consequently, STAT3 activity is repressed and the EGF signaling pathway ceases to be activated. A lack of Shoca-2 expression secondary to a genomic loss of the locus is frequently observed in metastatic colorectal cancer and correlates with an increase in phosphorylated STAT3 in these cells. Conversely, the ectopic expression of wild type Shoca-2 but not of a mutant form defective in its ability to bind to PP1beta suppresses STAT3-dependent tumor cell growth.

Conclusion: Our results identify Shoca-2 as a tumor suppressor that acts upon EGF stimulation as an adaptor protein to target STAT3 for dephosphorylation.

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 3081.
Abstract 3082: A paradoxical suppressive role for Src in urothelial carcinoma
Authors: Pollard Courtney , Thomas Shibu , Harding Michael A. , Theodorescu Dan
Published: February 2011

The most prevalent type of bladder cancer in western nations is urothelial carcinoma (UC). A significant number of patients with UC present with the muscle invasive form of the disease that is treated by radical cystectomy. Even with these treatments approximately 50% of these patients will develop metastases, resulting in essentially incurable disease. Thus, understanding the molecular basis of metastases in UC may prove useful in providing new therapeutic insights and targets. Src (v-Src sarcoma viral oncogene homolog) has been found to play pivotal oncogenic roles in a variety of in vitro and in vivo cancer models. Interestingly, when Src expression and activity was evaluated in a panel of bladder cancer cell lines and human bladder cancer tissue, it was shown that there was an inverse correlation between Src expression/activity and bladder tumor grade, suggesting that the Src oncogene might play a paradoxical suppressive role in UCs.

Herein, we show that that stable expression of constitutively active Src in a high grade bladder cancer cell line (UMUC3) corresponds to a decrease in in vitro monolayer growth (p = 0.05), Boyden Chamber migration (over a period of time where growth effects are inconsequential) (p < 0.01) and a reduction of experimental lung metastases in nude mice (p < 0.036). Supportive of this surprising finding that Src is a suppressor of various malignant phenotypes, we demonstrate that pharmacological inhibition of Src tyrosine kinase activity in the KU7 non invasive UC cells that have high Src expression and tyrosine kinase activity increases cellular proliferation and anchorage independent growth, compared to carrier treated controls. Interestingly, we show that stimulation of FGFR3, a tyrosine kinase receptor that has been associated with low grade and stage non- invasive bladder cancers with favorable prognoses, leads to induction of Src kinase activity in the KU7 cell line. Taken together, these data suggest direct evidence that Src acts paradoxically as a suppressor or aggressive urothelial cancer phenotypes and provide a possible explanation how FGFR3 activity may maintain a non aggressive tumor phenotype.

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 3082.
Abstract 3085: Overexpression of the NOTCH3 intracellular domain alters neuroendocrine phenotype in carcinoid tumor cells
Authors: Jaskula-Sztul Renata , Pisarnturakit Ponghtep , Kunnimalaiyaan Muthusamy , Chen Herbert
Published: February 2011

Introduction: There are four mammalian Notch receptors (Notch1-4), which exhibit unique and overlapping expression pattern and act as oncogenes or tumor suppressor genes depending on the cell and context type. We previously reported that Notch1 pathway is minimally active in neuroendocrine (NE) tumors. Furthermore, induction of the Notch1 signaling pathway by over- expression or by pharmacological treatment with valproic acid (VPA) and suberoyl bis-hydroxamic acid (SBHA) suppresses hormone secretion. However, the role of other Notch isoforms is not clear in carcinoid. In this study, we analyzed the presence of Notch isoforms and their regulatory role on chromogranin A (CgA), a clinically important NE marker, and achaete-scute complex-like1 (ASCL1), a known downstream target of Notch.

Methods: Expression of four Notch isoforms was quantified by real time RT-PCR from parental BON cells (GI carcinoid) and VPA treated BON cells. pcDNA3.3 TOPO plasmid containing constitutively expressed human active portion of Notch3, NICD3, was transiently transfected into BON cells and the cell lysates were tested for the presence of NOTCH3. The levels of NE markers such as CgA and ASCL1 were analyzed by Western blot.

Results: Gene expression analysis showed that the parental BON cells had very minimal levels of Notch1-3. Notch4 expression was not detected. In VPA treated cells, the levels of Notch1, 2 and 3 were increased significantly. Overall, the Notch3 expression level was higher than Notch1 and 2 in VPA treated cells. Importantly, there was a 60-fold induction of Notch3 expression in VPA treated cells compared to parental untreated cells. VPA treatment also resulted in a 15-fold and 20-fold increase for Notch1 and Notch2 respectively whereas Notch4 was not detected in these cells. The constitutive expression of NICD3 in BON cells resulted in a reduction in ASCL1 and CgA.

Conclusions: Carcinoid tumor cells have a paucity of all Notch isoforms, including Notch3. For the first time, we demonstrate that Notch3 regulates the NE phenotype, and may play an important role in regulating carcinoid tumor progression. These findings warrant further investigation on targeting Notch3 for carcinoid cancer therapy.

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 3085.
Abstract 3086: Gain of chromosome 13 is a cause of CDK8 overexpression associated with colorectal adenoma to carcinoma progression
Authors: Carvalho Beatriz , Postma Cindy , Mongera Sandra , van Diemen Pien , Ylstra Bauke , Meijer Gerrit A.
Published: February 2011

Introduction: Colorectal adenomas are common precursors of colorectal cancer (CRC). About only 5% of adenomas progress to cancer and this progression is mostly associated with overall onset/increase of chromosomal instability. Gain of 13q is often implicated in this progression of adenoma to carcinoma (1). Until recently however no genes were identified to be the drivers of this amplicon. Recently, Firestein and collaborators (2) showed that cyclin 8 (CDK8), at 13q12.13, functions as an oncogene in CRC.

The aim of this study was to evaluate CDK8 gene dosage effects in colorectal adenoma to carcinoma progression.

Material and methods: Sixty seven colorectal tumours (34 adenomas and 28 carcinomas) were analysed by array CGH (5k BAC platform, including contig coverage of 13q) and by expression microarray (30k Compugen library). Integration of DNA copy number dosage and gene expression was performed using the Ace-it tool (3).

Results: In the tumours analysed we observed 13q copy number gain in 9% and 46% of adenomas and carcinomas, respectively. Integrating copy number and mRNA expression with the differential upregulation of genes between carcinomas and adenomas, provided us with a list of 43 genes. Within this list, CDK8 ranked 7th in significancy (p=0.003).

Conclusions: Copy number gain of 13q has a gene dosage effect on CDK8 mRNA expression, indicating a role of this gene in colorectal adenoma to carcinoma progression.

(1) Hermsen M, Postma C, Baak J, Weiss M, Rapallo A, Sciutto A, Roemen G, Arends JW, Williams R, Giaretti W, De Goeij A, Meijer G. Colorectal adenoma to carcinoma progression follows multiple pathways of chromosomal instability. Gastroenterology 2002 Oct;123(4):1109-19.

(2) Firestein R, Bass AJ, Kim SY, Dunn IF, Silver SJ, Guney I, Freed E, Ligon AH, Vena N, Ogino S, Chheda MG, Tamayo P, Finn S, Shrestha Y, Boehm JS, Jain S, Bojarski E, Mermel C, Barretina J, Chan JA, Baselga J, Tabernero J, Root DE, Fuchs CS, Loda M, Shivdasani RA, Meyerson M, Hahn WC. CDK8 is a colorectal cancer oncogene that regulates beta-catenin activity. Nature 2008 Sep 25;455(7212):547-51.

(3) van Wieringen WN, Belien JA, Vosse SJ, Achame EM, Ylstra B. ACE-it: a tool for genome-wide integration of gene dosage and RNA expression data. Bioinformatics. 2006 Aug 1;22(15):1919-20.

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 3086.
Abstract 3088: Mammalian sterile-20 like kinase 1(Mst1) upregulates cyclin D1 to promote hepatocellular carcinoma cell growth
Authors: Ng Yuen Keng , Lui Vivian Wai Yan , Cheng Alfred Sze Lok , Chen George Gong , Lai Paul Bo-san
Published: February 2011

Although hepatocellular carcinoma (HCC) is highly related to the chronic infection of hepatitis B or C viruses, the progression of the malignancies is caused by the increased proliferation of the HCC cells. The proliferation of tumor cells is usually resulted from dysregulations in cell cycle progression or apoptosis induction. Current evidence indicates that the cytoplasmic serine/threonine kinase Mammalian Sterile-20 like kinase 1 (Mst1) suppresses HCC development by inactivating the oncoprotein YAP65 in normal livers. Furthermore, upon DNA damage, the caspase cleavage of the full-length cytoplasmic Mst1 proteins is activated, which then leads to Mst1 nuclear translocation and apoptosis induction via transcriptional activation of the Forkhead tumor suppressor Foxo3a. Using an HCC cell line model, the Hep3B cells, we found that transient transfection of Mst1 did not induce apoptosis, but rather enhanced the cellular proliferation by 74% within 2 days after transfection. The growth-promoting activity of Mst1 in the HCC cells was confirmed as Hep3B cell growth was significantly reduced by transient expression of the Mst1 kinase dead mutant (26% reduction) or Mst1 specific shRNAs (62% reduction). The Mst1-induced cell proliferation was further evidenced by the presence of Ki67 nuclear staining in the transfected Hep3B cells while the cells expressing the kinase dead mutant of Mst1 did not have Ki67 nuclear staining. Moreover, Western blot analyses showed that phosphorylation of YAP65 was not dependent upon Mst1 overexpression, suggesting that the hippo pathway was not involved in the Mst1 induced cell proliferation. Interestingly, Western blotting showed that such a growth-promoting activity of Mst1 in Hep3B cells was associated with a sustained upregulation of Cyclin D1 expression, an important marker for proliferation, after Mst1 overexpression. Our findings suggest that an alteration of Mst1 function exists in HCC cells, which drives aberrant HCC proliferation via Cycin D1 upregulation.

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 3088.
Abstract 309: RSK2 mediates NF-κB activity through the phosphorylation of IκBα in the TNF-R1 pathway
Authors: Cho Yong Yeon , Peng Cong , Ma WeiYa , Bode Ann , Dong Zigang
Published: February 2011

The ribosomal S6 kinase 2 (RSK2) mediates proliferation, survival, and malignant transformation. Activation of nuclear factor kappa B (NF-κB) results in the transcription of anti-apoptotic genes and is mediated by I-kappaB kinases (IKKs). IKK(α/β) phosphorylates IκBα at Ser32/Ser36 in the presence of TNF-α to induce IκBα degradation and NF-κB activation. The purpose of this study was to determine the potential role of RSK2 in mediating TNF-α-induced signaling. Notably, we found that RSK2 is activated by TNF-α and directly phosphorylates IκBα at Ser32 leading to IκBα degradation to promote the activation and translocation of the NF-κB subunits, p65 and p50, to the nucleus. This resulted in increased NF-κB activity, which served as a mechanism for RSK2 blockage of TNF-α induction of apoptosis and enhanced cell survival. Thus a new kinase that directly phosphorylates IκBα to promote its degradation is identified in TNF-R1 pathway.

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 309.
Abstract 3091: Oncogenic roles of nuclear VCP in oral cancer development
Authors: Chiu I-Wen , Li Chien-Feng , Lai Chien-Chen , Lai Ming-Tsung , Chen Chih-Mei , Lin Ying-Ju , Wan Lei , Tseng Hsien-Chang , Hua Chun-Hung , Tsai Ming-Hsui , Hsu Wei-Yi , Tsai Fuu-Jen , Sheu jim Jinn-Chyuan
Published: February 2011

VCP is a member of AAA-ATPase family that includes putative ATP-binding proteins involved in nuclear envelope reconstruction, cell cycle regulation, Golgi reassembly, suppression of apoptosis, and DNA-damage response. Due to the novel functions, VCP overexpression was linked to cancer development and suggested as a prognostic tumor marker for poor clinical outcome. Our preliminary data of SNP array analysis on 33 fresh clinical OSCC samples identified an amplified region at chromosome 9p13.3 containing the VCP gene. This finding was further validated by FISH analysis on a larger scale using paraffin-embedded oral cancer tissues. Consistent with genomic copy alterations, the mRNA and protein expression levels of VCP were also found higher in OSCC tissues. Interestingly, the nuclear VCP staining correlates with VCP gene amplification and shorter overall survival, suggesting the novel functions of VCP in nucleus during OSCC development. In this study, we identified several nuclear binding partners for VCP in OSCC cells, and signaling networks controlled by VCP during OSCC development were discussed.

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 3091.
Abstract 3092: The roles of SRC-3 and its isoform SRC-3Δ4 during the progression of DCIS to invasive breast cancer
Authors: Long Weiwen , Medina Daniel , Tsai Sophia , Tsai Ming-Jer , O'Malley Bert
Published: February 2011

Accumulating evidence has shown that SRC-3 plays important roles in tumor metastasis. SRC-3 gene deletion suppresses both v-Ha-ras- and polyomavirus middle T (PyMT) transgene-induced breast tumor metastasis to the lung. SRC-3 overexpression is highly correlated with metastatic phenotype in human breast cancer. SRC-3 promotes cancer cell invasion by co-activating AP-1 and PEA-3-mediated matrix metalloproteinase (MMP) expression. We recently found that a SRC-3 isoform with the deletion of exon 4 (SRC-3Δ4) promotes breast cancer cell migration and mammary tumor metastasis by directly mediating EGF signal transduction from EGFR to c-Src and FAK. One of the key tasks in the field of breast cancer research is to identify what factors regulate the progression of ductal carcinoma in situ (DCIS) to invasive breast cancer. Given the importance of SRC-3 and SRC-3Δ4 in breast tumor metastasis, we hypothesize that SRC-3 and/or SRC-3Δ4 promote the progression of DCIS to invasive breast cancer. To test this hypothesis, we either stably overexpressed or stably knocked down SRC-3 or SRC-3Δ4 in two DCIS cell lines (DCIS.COM and SUM225) by lentiviral transduction. Stable knockdown of SRC-3 significantly decreased cell proliferation and cell invasion, whereas knockdown of SRC-3Δ4 only decreased cell invasion. Conversely, Overexpression of either SRC-3 or SRC-3Δ4 promote cell invasion, which is partly due to the increased Akt phosphorylation. We then injected the DCIS cells into the mammary ducts of athymic nude mice. The effect of SRC-3 and SRC-3Δ4 on the formation of DCIS and invasive lesions is under investigation. Furthermore, the underlying molecular mechanisms will be analyzed as well.

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 3092.
Abstract 3098: Myc preferentially transforms hematopoietic stem cells into Precursor B cell lymphoblastic leukemia/lymphoma
Authors: Sugihara Eiji , Shimizu Takatsune , Ishizawa Jo , Okada Seiji , Miwa Masanao , Saya Hideyuki
Published: February 2011

Overexpression of Myc oncogenes (c-Myc, N-Myc and L-Myc) is frequently found in a wide range of tumors. Although many reports have shown that Myc can directly induce tumors in mice models, the cell-of-origin of the Myc-induced tumor is still unclear. In this study, we attempted to determine the cell-of-origin in the Myc-induced hematopoietic tumor by using bone marrow transplantation model. Bone marrow (BM) cells were harvested from 5FU-treated mice (6 to 8-week-old C57BL/6 mice) and then infected with retroviral vectors to express one of Myc genes, N-Myc. The infected cells were intravenously transplanted into irradiated syngenic mice. As a result, all mice transplanted with N-Myc-transduced BM cells died around 2 months. Those mice showed enlarged lymph nodes, splenomegaly and invaded livers. Abnormally increased WBCs in those mice showed B220+CD19+CD43+/−IgM−, indicating that enhanced expression of N-Myc in BM cells caused Precursor B cell lymphoblastic leukemia/lymphoma (Pre-B LBL). To determine the cell-of-origin of this tumor, the N-Myc-transduced BM cells were fractionated into hematopoietic stem cells (HSCs), committed lymphoid progenitors (CLPs) or myeloid progenitors (MPs) by cell sorter, and those fractions were transplanted into irradiated recipients. Limiting dilution analysis revealed that mice transplanted with HSCs had Pre-B LBL at significant higher frequencies (1:184) than mice transplanted with CLPs (1:558) or MPs (1:9286). Furthermore, to determine whether more lineage-committed cells can be directly the cell of origin, we sorted immature-B cells transduced with N-Myc from non-treated BM cells and transplanted those cells into recipients. While we could not obtain any tumors from those transplanted mice, mice transplanted with immature-B (B220+CD19+IgD−IgM−) cells derived from p16Ink4a−/−p19Arf−/− mice had Pre-B LBL, suggesting that committed B cells could be the direct cell-of-origin in the absence of p16Ink4a and p19Arf genes which are known as tumor suppressor genes. Lastly, we confirmed that another Myc family gene c-Myc also could induce Pre-B LBL, showing similar histopathology and immunophenotype to the N-Myc-induced pre-B LBL. Collectively, our findings indicate that Myc genes can preferentially transform HSCs into Pre-B LBL and, that p16Ink4a and p19Arf genes can be crucial barriers to block Myc-induced oncogenic stress in more committed cells than HSCs.

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 3098.
Abstract 3102: Oncogenic PWWP-domain protein WHSC1L1 links the homeobox transcription factor IRX3 in breast cancer
Authors: Liu Gang , YANG Zeng-Quan , Ethier Stephen P.
Published: February 2011

Amplification of the 8p11-12 region has been found in about 10-15% of human breast cancer and may be associated with poor prognosis. Earlier, we used genomic analysis of copy number and gene expression to perform a detailed analysis of the 8p11-12 amplicon for identifying candidate oncogenes in breast cancer. We identified Wolf-Hirschhorn syndrome candidate 1-like 1 (WHSC1L1) as a candidate oncogene based on statistical analysis of copy number increase and over expression. The WHSC1L1 gene encodes a PWWP domain protein that regulates histone methylation marks, and regulates the transcription profile and the differentiated function of cells. To address the question of whether WHSC1L1 possesses transforming properties, we established lentiviral expression constructs containing the WHSC1L1 as well as other 20 candidate genes of 8p11-12 region. MCF10A cells were infected with these lentiviral vectors and assayed for alterations in growth rates, growth factor-independent proliferation, anchorage-independent growth and for three-dimensional morphogenesis assays in Matrigel culture. From these experiments, we found that the WHSC1L1 is the most potently transforming oncogene we tested from the 8p11-12 region. Furthermore, knockdown of this gene in WHSC1L1 amplified breast cancer cells resulted in profound loss of growth and survival potential in these cells. To identify genes that may be regulated in their expression by the WHSC1L1 when it is amplified and over expressed, we performed expression profiling of MCF10A cells, MCF-10AWHSC1L1 cells, and WHSC1L1 amplified SUM-44 breast cancer cells. Analysis of genes altered by over expression of WHSC1L1 in MCF10A-WHSC1L1 cells and in SUM-44 cells resulted in the identification of 184 WHSC1L1 candidate target genes. Among them was the iroquois homeobox 3 gene (IRX3), a member of the Iroquois homeobox transcription factor family. The regulation of IRX3 gene expression by WHSC1L1 was validated in SUM44 breast cancer cells using WHSC1L1 knock down. IRX3 mRNA was dramatically down-regulated in SUM-44 cells after WHSC1L1 shRNA infection. Intriguingly, in our array CGH study we found that SUM-44 cells also have a gene amplification of IRX3. Thus, our finding indicates that WHSC1L1 is the major driving oncogene in the 8p11-12 amplicon, and provides the first evidence that WHSC1L1 and IRX3 are genetically linked in subset of breast 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 3102.
Abstract 3103: Survivin expression is enhanced by the oncoprotein SF2/ASF in non-small cell lung cancer
Authors: Pajares Maria J. , Ezponda Teresa , Agorreta Jackeline , Echeveste Jose I. , Lopez-Picazo Jose M. , Torre Wenceslao , Pio Ruben , Montuenga Luis M.
Published: February 2011

Recent data have shown that the regulation of mRNA metabolism contributes to the genesis of a variety of diseases, including cancer. Modifications in the levels of mRNA processing proteins can elicit global changes in the profile of mRNA expression, affecting a number of cancer-associated genes. The splicing factor SF2/ASF has been described as an oncoprotein with roles both in the establishment and maintenance of a transformed phenotype. The mTOR pathway activation is required for SF2/ASF-mediated transformation, but the specific effectors involved in the SF2/ASF oncogenic potential are not well known. In the present work, we examined the role of SF2/ASF in human non-small cell lung cancer (NSCLC) and analyzed the molecular mechanisms involved in the SF2/ASF-oncogenic potential. First, we studied the expression of SF2/ASF in human NSCLC by Western blotting and immunocytochemistry. SF2/ASF was overexpressed in most lung cancer cell lines and primary tumors. We next downregulated SF2/ASF expression in NSCLC cells using siRNAs. Inhibition of SF2/ASF induced cell cycle arrest and apoptosis. We found that SF2/ASF inhibition caused a decrease in the main isoform of survivin, an anti-apoptotic protein upregulated in several types of cancer. SF2/ASF specifically bound survivin mRNA, increasing its stability and translation. The translation of survivin mRNA was induced through an mTORC1 pathway-dependent mechanism by the phosphorylation and inactivation of the translational repressor 4E-BP1. Moreover, we found a strong correlation between the expression of SF2/ASF and survivin in both human NSCLC lung cancer cell lines and primary tumors, supporting the concept that survivin expression levels are controlled by SF2/ASF. In conclusion, we show that SF2/ASF over-expression plays an important role in lung cancer cell survival and provide novel data on the molecular mechanisms of SF2/ASF-mediated oncogenic transformation.

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 3103.
Abstract 3104: The role of Pim-3 kinase in NF-κB signaling and transformation of pancreatic cancer
Authors: Xu Dapeng , Bednarski Brian , Kim Hongjin , Baldwin Albert , Baines Antonio T.
Published: February 2011

Pancreatic ductal adenocarcinoma (PDAC) is the 4th most common cause of cancer deaths in the United States. Due to the aggressive nature of this cancer and the lack of biomarkers for early detection, the incidence and mortality rates for PDAC are nearly equivalent. A better understanding of the molecular mechanisms leading to the development of pancreatic cancer remains a major goal for defining appropriate treatment strategies. Past studies have shown that the proto-oncogene Pim-3 kinase is expressed in pancreatic cancer and is able to phosphorylate the pro-apoptotic protein Bad to block Bad-mediated apoptosis in human pancreatic cancer cell lines. With these and other observations implicating Pim kinases as oncogenes and inhibitors of apoptosis, the purpose of our study is to further characterize the functional significance of Pim-3 in PDAC growth as well as identify possible downstream targets. We hypothesize that inhibition of Pim-3 signaling will be an effective approach for antagonizing the aberrant growth of pancreatic cancer. Initially, we confirmed by immunohistochemistry that Pim-3 protein is aberrantly expressed in human pancreatic cancer and pancreatitis tissue and is constitutively expressed in a panel of human pancreatic cancer cell lines. Also, we found that suppression of Pim-3 by shRNAs significantly decreased cell growth and caused a reduction in invasion of pancreatic cancer cells in Matrix-gel. To our knowledge, this is the first time that any of the Pims have been associated with invasion in pancreatic cancer. Most recently, other members of the Pim kinase family have been shown to activate NF-κB in cancer. From our studies, we observed that suppression of Pim-3 upregulated IκBα and decreased phospho-NF-κB p65 (Ser536), suggesting an effect on NF-κB transcription activity. Our results indicate the importance of Pim-3 in various aspects of transformation of pancreatic cancer and how NF-κB may be a potential downstream target of Pim-3 signaling in PDAC. These findings will allow us to critically validate Pim kinases as novel biomarkers and therapeutic targets for pancreatic 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 3104.
Abstract 3107: Novel molecular mechanisms of MDM2-induced p21Waf1 degradation
Authors: Xu Hongxia , Zhang Zhuo , Li Mao , Zhang Ruiwen
Published: February 2011

The MDM2 oncogene is overexpressed in many human cancers, and the tumorigenicity of MDM2 has mainly been attributed to the auto-regulatory loop it forms with p53. However, there is increasing evidence that the tumorigenicity of MDM2 is also dependent upon its p53-independent activities. One of the p53-independent functions of MDM2 is its induction of the ubiquitin-independent proteasomal degradation of p21Waf1. The present study was designed to characterize the mechanism(s) by which MDM2 induces p21Waf1 degradation in the p53-independent setting. We determined the regions of MDM2 required for p21Waf1 degradation using pull-down assays and Western blotting, and then examined the mechanisms using limited proteolysis and fluorescence resonance energy transfer (FRET). We demonstrated that the MDM2-p21Waf1 interaction depends on MDM2's central domain, and that nuclear localization of both proteins is necessary for p21Waf1 degradation. Specifically, amino acids 226-250 of MDM2 are required for p21Waf1 binding and degradation, and amino acids 251-260 are necessary for p21Waf1 degradation. The latter region induces a conformation change in p21Waf1, increasing its binding to the C8 subunit of the proteasome, leading to its degradation. When MDM2 lacked either segment (aa 226-250 or aa 251-260), it lost its capacity to promote p21Waf1 degradation and cell cycle progression. In summary, our results demonstrate a novel mechanism by which MDM2 induces the ubiquitin-independent proteasomal degradation of an intact protein. This previously unknown chaperone-like function of MDM2 induces a conformational change in p21Waf1, leading to its increased binding to the C8 subunit of the proteasome to induce its subsequent degradation. It is possible that this mechanism may also be active for other substrates. Thus, the present study provides further evidence supporting the importance of the p53-independent activities of MDM2, confirming the significance of MDM2 as a target for cancer therapy. (Supported by NIH/NCI grants R01 CA 112029 and R01CA121211.)

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 3107.
Abstract 3109: Myc confers aggressive medulloblastoma phenotypes by regulating cell migration and adhesion genes
Authors: Picard Daniel J. , Zhou Limei , Hu Yaqi , Li Meihua , Shih David , Stearns Duncan , Cohn Susan , Hawkins Cynthia E. , Rutka James T. , Taylor Michal D. , Huang Annie
Published: February 2011

Mechanisms by which Myc confers aggressive phenotypes and adverse outcomes in medulloblastoma remain largely unknown. In this study, we demonstrate using 2 medulloblastoma cell line models that high Myc expression increases cell migration/invasion and induces metastatic orthotopic tumors which recapitulate the aggressive histology of primary anaplastic medulloblastoma. Using ChIP-chip and expression analysis on Myc transformed medulloblastoma cell lines, we identified a subset of cell migration and adhesion genes as direct Myc repressed transcriptional targets. These include ING4, PVRL3, PPAP2B and Tsp-1/THBS1, a potent tumor suppressor not previously implicated in medulloblastoma. Tsp-1 expression in medulloblastoma cell lines and primary tumors were consistently and significantly diminished in the presence of high Myc (n=101, p=0.032). Using ChIP and reporter assays we confirmed Myc and Max co-localization to a basal Tsp-1 promoter and decreased Tsp-1 transcription in the presence of Myc. Our analyses also revealed that JPO2, a Myc interacting protein linked to metastatic medulloblastoma, directly binds the Tsp-1 promoter and augments Myc-mediated Tsp-1 repression. Interestingly, we observed that stable Tsp-1 expression significantly diminished soft agar growth and drastically decreased cell invasion/migration in high-Myc expressing medulloblastoma cell lines without effects on cellular proliferation. Our collective findings highlight a novel and important role for Tsp-1 in Myc- induced metastatic medulloblastoma phenotypes and suggest Tsp-1 agonists may represent attractive, therapeutics for primary metastatic medulloblastoma.

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 3109.
Abstract 3112: TIS21BTG2/PC3 enhances down-regulation of c-Myc expression during all-trans-retinoic acid-induced differentiation of acute promyelocytic leukemia cells
Authors: Imran Muhammad , Park Tae Jun , Lim In Kyoung
Published: February 2011

c-Myc is a transcription factor that promotes cell growth and proliferation. Deregulated c-myc can induce aberrant proliferation, loss of terminal differentiation and oncogenesis. On the other hand, the 12-O-tetradecanoyl phorbol-13-acetate inducible sequence 21 (TIS21), ortholog of human B-cell translocation gene-2 (BTG2) is an antiproliferative tumor suppressor gene, working as a pan-cell cycle regulator. In this study we have evaluated the effects of all-trans retinoic acid (ATRA) and TIS21BTG2/PC3 on the expression c-Myc in HL-60 promyelocytic leukemia cells, harboring amplified c-myc. We observed that ATRA induced granulocytic differentiation of HL-60 cells as monitored by the expressions of CD11b, CD14, CD38 and microscopic examination of the cells. ATRA treatment led to decrease in cells proliferation accompanied by down-regulation of cyclin D1, cyclin E and cyclin A while up-regulation of p21WAF1 and p27KIP1 and hence G1 phase arrest. Expression of c-Myc was significantly down-regulated during all-trans-retinoic acid induced differentiation, while BTG2TIS21/PC3 was up-regulated (∼2.5 folds). Employing adenovirus carrying TIS21 gene, we observed the slight down regulation of c-Myc expression; TIS21 however, enhanced ATRA-induced differentiation of HL-60 cells to granulocytes and significantly increased down-regulation of c-Myc expression at protein level but mRNA level didn't change. Proteosomal inhibition with MG132 didn't attenuate c-Myc protein levels indicating that ubiquitination/proteosome-mediated proteolysis is not involved in TIS21BTG2/PC3 mediated down-regulation of c-Myc. Inhibition of PI3K/Akt/mTOR pathway with LY294002 however, suggested the possible involvement of TIS21BTG2/PC at least in part through PI3K/Akt/mTOR pathway in regulating c-Myc expression. The present results suggest the modulating effect of TIS21BTG2/PC3 on c-Myc expression in a promyelocytic leukemia cells.

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 3112.
Abstract 3113: Loss of TLE1 tumor suppressor accelerates myeloid leukemia development in cooperation with N-Myc
Authors: Ramasamy Selvi , Chen Xi , Wang Jianfeng , Ding Daching , Sweetser David A.
Published: February 2011

Transducin-like enhancer of split-1 (TLE1) is a novel tumor suppressor gene that is deleted or methylated in subgroups of acute myeloid leukemia (AML) and other hematological malignancies. TLE1 belongs to a family of Gro/TLE proteins that function as corepressors that can bind and potentially inhibit numerous transcription factors known to be involved in development and carcinogenesis including myc, beta-catenin, NF-kB, and TGF-B. In Drosophila Groucho is recognized as a master regulatory gene in development. Our studies and those from other groups have shown that over-expression of TLE1 in leukemia cells slows cell cycle progression, colony formation and tumor growth in xenografts, while silencing results in increased cell proliferation. To further evaluate the role of TLE1 in development and oncogenesis we have knocked out TLE1 in mice. These mice are viable and do not spontaneously develop malignancies in the absence of additional cooperating oncogenes. In Drosophila the TLE homologue Groucho binds and represses Drosophila Myc expression of target genes. N-Myc is important for hematopoietic stem cell proliferation, survival and differentiation and is over-expressed in most AML samples. We postulated that TLE 1 might be an important regulator of N-Myc activity in leukemia and the loss of TLE may accelerate the leukemia development in cooperation with N-Myc. We demonstrate here that the loss of Tle1 cooperates with N-Myc to dramatically increase the serial replating and proliferation of hematopoietic progenitor cells from fetal livers. Mice transplanted with N-Myc transduced hematopoietic cells from the fetal liver of Tle1 knockout mice developed leukemia with a much shorter latency as compared with fetal liver cells from wild type mice. We are currently investigating the mechanisms of this cooperation. This is the first demonstration that Tle1 is a potent modulator of Myc induced tumorigenesis and may have implications in a broader spectrum of malignancies.

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 3113.