bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 1470: 15-Deoxy-Δ12,14-prostaglandin J2 up-regulates expression of p53 and p21 through Nrf2-driven heme oxygenase-1 induction in human breast cancer (MCF-7) cells
Authors: Kim Do-Hee , Song Na-Young , Na Hye-Kyung , Kim Eun-Hee , Surh Young-Joon
Published: February 2011

Heme oxygenase-1 (HO-1) is a stress-responsive enzyme that has antioxidant and cytoprotective functions. 15-Deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2), an endogenous ligand of peroxisome proliferator-activated receptor γ (PPARγ), has been reported to induce HO-1 and other antioxidant enzymes in certain cell lines. In the present work, we investigated the effects of HO-1 on the expression of p53 and p21 induced by 15d-PGJ2 in human breast cancer (MCF-7) cells. Treatment of MCF-7 cells with 15d-PGJ2 (30 μM) led to time-dependent increases in the expression of p53 and p21 as well as HO-1. The up-regulation of p53 and p21 expression by 15d-PGJ2 was abrogated by pharmacological inhibition with zinc protophophyrin (10 μM) or si-RNA knock down of HO-1. Nrf2, a basic-leucine zipper transcription factor, plays a key role in regulating the up-regulation of many antioxidant enzymes including HO-1. In MCF-7 cells transfected with NRF2 si-RNA, 15d-PGJ2 failed to induce expression of p53, p21 and HO-1. In addition, HO-1 inducers, such as cobalt protoporphyrin (25 μM) and hemin (10 μM), upregulated the expression of p53 and p21 without eliciting any apparent cytotoxicity. HO-1 degrades heme to produce iron, biliverdin, and carbon monoxide. We hypothesize that iron, a by-product of HO-1-catalyzed reactions, could mediate 15d-PGJ2-induced expression p53 and p21. Up-regulation of p53 and p21 expression by 15d-PGJ2 was abrogated by the iron chelator desferrioxamine (25 μM) in MCF-7 cells. Iron released from heme by HO-1 activity is mostly in the ferrous (Fe2+) form. When MCF-7 cells were treated with the iron-specific chelator phenanathroline (10 μM), 15d-PGJ2-induced expression of p53 and p21 was attenuated. However, p53 induction by 15d-PGJ2 was not affected by GW9662, a PPARγ antagonist. In addition, levels of the iron-sequestering protein H-ferritin were induced by 15d-PGJ2 in MCF-7 cells. Addition of the antioxidant N-acetylcysteine lowered the 15d-PGJ2-mediated H-ferritin levels. Recently, it has been reported that p21 as a positive regulator of Nrf2 extends the prosurvival function of p53 through recruitment of stress-response genes. Up-regulation of p53 and p21 expression via Nrf2-driven HO-1 induction and subsequent release of iron together with elevated expression of H-ferritin may confer resistance to oxidative damage in MCF-7 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 1470.
Abstract 1476: Cell surface nucleolin acts as a specific receptor of Tipα, a carcinogenic factor released from H. pylori
Authors: Suganuma Masami , Watanabe Tatsuro , Tsuge Hideaki , Hirano Kazuo , Beppu Masatoshi , Yamaguchi Kensei , Takahashi Atsushi , Fujiki Hirota
Published: February 2011

TNF-α inducing protein (Tipα), a unique carcinogenic factor of H. pylori, has the potential to transform Bhas 42 (v-H-ras transfected BALB/3T3) cells. Tipα directly binds to gastric cancer cells and then induces expression of TNF-α gene, an endogenous tumor promoter, in gastric epithelial cells. H. pylori obtained from gastric cancer patients release significant amounts of Tipα into the culture medium compared with H. pylori of gastritis patients, indicating that Tipα plays important role in gastric cancer development. Recently, Tipα vaccination was reported to significantly reduce the colonization of H. pylori in mice associated with high levels of Tipα-specific antibody: All the results indicate that Tipα is a suitable molecular target for gastric cancer prevention. We recently demonstrated that nucleolin is a specific binding protein for Tipα in mouse gastric cancer cells MGT-40 using FLAG pull-down assay. Although nucleolin is known to a be non-ribosomal protein in nucleoli, we found that nucleolin is present on the cell surface of MGT-40 cells and various human gastric cancer cell lines, such as KATOIII and AGS, as determined by flow cytometry with anti-NUC295 antibody (recognizing cell surface nucleolin), and by cell fractionation. Pretreatment with anti-NUC295 antibody induced the enhancement of Tipα incorporation into the MGT-40 cells, but pretreatment with tunicamycin, an inhibitor of N-glycosylation decreased the amounts of cell surface nucleolin and inhibited internalization of Tipα, resulting in down-regulation of TNF-α gene expression. We here present evidence that cell surface localized nucleolin acts as a receptor of Tipα and shuttles Tipα from cell surface to cytosol and nuclei, and we discuss the significant roles of cell surface nucleolin in gastric cancer development by H. pylori infection.

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 1476.
Abstract 1483: 15-Deoxy-D12,14-prostaglandin J2 upregulates 15-hydroxyprostaglandin dehydrogenase expression through activation of AP-1 signaling in human colon cancer cells
Authors: Park Jong-Min , Cho Kyung-Hwa , Myung Seung-Jae , Surh Young-Joon , Na Hye-Kyung
Published: February 2011

Abnormal up-regulation of cyclooxygenase-2 (COX-2) expression has been considered as a key oncogenic event in inflammation-associated human colon carcinogenesis. It was reported that 15-hydroxyprostaglandin dehydrogenase (15-PGDH), a physiological antagonist of COX-2 in its catabolism, is ubiquitously lost in human colon cancer, and hence considered as a tumor suppressor. However, the molecular mechanisms underlying regulation of 15-PGDH expression in colon carcinogenesis remain largely unresolved. In the present study, we found that 15-deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2), one of the terminal products of COX-mediated arachidonic acid metabolism, upregulates the expression of 15-PGDH in the human colon cancer HCT116 cells in a time and concentration-dependent manners. 15d-PGJ2 treatment (10 μM) significantly upregulated the expression of 15-PGDH and its mRNA transcript. 15-PGDH activity was also elevated by 15d-PGJ2 treatment. In a subsequent experiment, we performed cDNA microarray analysis with HCT116 cells exposed to 15d-PGJ2 (10 µM) for 3 h. We observed that C/EBP delta, FOS-like antigen 1, and c-Jun (AP-1) were the most highly induced genes upon treatment with 15d-PGJ2. Based on these findings, we determined whether 15d-PGJ2 could activate the DNA binding of AP-1, a representative transcription factor that preferentially binds to the promoter region of 15-PGDH. 15d-PGJ2 caused increased DNA binding activity of AP-1 in HCT116 cells. Moreover, siRNA knock down of c-Jun, a major subunit of AP-1, significantly reduced 15-PGDH expression as well as AP-1 DNA binding induced by 15d-PGJ2. To elucidate the upstream signaling pathways responsible for AP-1 activation and 15-PGDH expression induced by 15d-PGJ2, we examined the effect of this cyclopentenone prostaglandin on the activation of mitogen-activated protein kinases (MAPKs), such as ERK, p38 and JNK, and also Akt. We observed that a pharmacological inhibition of Akt/PKB with LY294002 abrogated the 15d-PGJ2-induced 15-PGDH expression and AP-1 DNA binding activity, while inhibitors of MAPKs failed to affect these events. Taken together, these finding suggest that 15d-PGJ2 upregulates the expression of 15-PGDH via Akt-mediated AP-1 activation.

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 1483.
Abstract 1486: Increased expression and phosphorylation of eukaryotic initiation factor 4E (eIF4E) and 4E-binding protein (4E-BP1) correlates with disease progression and high risk clinical/pathological features in melanoma
Authors: Chakravarti Nitin , Warneke Carla L. , Johnson Marcella M. , Davies Michael A. , Prieto Victor G.
Published: February 2011

Cutaneous melanoma is an increasingly important public health problem, as the incidence of this disease has increased 15-fold during the last four decades, more than any other malignancy. There is a great need for biomarkers that can be used both for both diagnosis and prognosis in melanoma. Identification of such biomarkers may provide insight into the pathogenesis of this disease, and also suggest rational therapeutic approaches. Protein translation has been shown to play a significant role in carcinogenesis in various organ systems. Several pathways upstream of protein translation are deregulated during melanoma development, including the RAS-RAF-MAPK and the PI3K-AKT kinase cascades. It is unknown whether dysregulated translational machinery contributes to the pathogenesis of melanoma. In order to test the hypothesis that dysregulation of protein translation plays a significant role in melanoma, we have performed immunohistochemical analysis to evaluate expression of phospho-4E-BP1 (p4E-BP1), phospho-eIF4E (peIF4E) and total eIF4E in benign nevi (n=49), primary melanomas (n=130), and melanoma metastases (n=47 cases) specimens obtained from the Department of Pathology of The University of Texas M. D. Anderson Cancer Center. A significant positive correlation was observed between the percentage of positively staining cells and staining intensity for p4E-BP1 (p<0.0001) and peIF4E (p<0.0008) with progression from benign nevi to primary tumors, and from primary tumors to metastases. Significantly higher levels of p4E-BP1 (p=0.0085) and total eIF4E (p=0.0173) proteins were observed in samples with vertical growth phase than in samples with radial growth phase only. Higher levels of p4E-BP1 were also observed in samples with ulceration (p=0.0167), which is a well-established marker of poor clinical outcomes in patients with local and regional melanoma. Thus, total and phosphorylated eIF4E and phosphorylated 4E-BP1 correlate with disease progression and high risk clinical and pathological features in melanoma. These findings provide new insight into the molecular pathogenesis of melanoma, and suggest that protein translation machinery may be an important therapeutic target in this disease.

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 1486.
Abstract 149: DNA methylation biomarker discovery using the Methyl-Profiler PCR Array System
Authors: Shaffer Jonathan M. , Liu Chun-Xiang , Gu Xiujing , Liu GuoZhen , Xiang Yan , Lin Yuye , Han Rui , Quellhorst George J. , Boon Kathy
Published: February 2011

Histone modifications and DNA methylation are epigenetic events that can modulate gene expression patterns associated with normal development and disease pathology. Epigenetic alterations are clearly involved in breast cancer initiation and progression, as they silence tumor suppressor genes and activate proto-oncogenes. As a result, the profiling of gene promoter DNA methylation status can lead to the identification of novel biomarkers which can aid in the development and improvement of diagnostic, prognostic, and therapeutic treatments. The Methyl-Profiler PCR Array System proves to be quite useful for these purposes.

The Methyl-Profiler DNA Methylation technology method is designed for semi high-throughput gene/target-specific DNA methylation profiling. The method involves the selective digestion of sample DNA with methylation-specific restriction enzymes, followed by precise quantization of intact remaining target DNA by real-time PCR using assays specially designed and validated for high G/C content amplicons. Attesting to the power of this method, as little as one µg of genomic DNA can be used to profile the methylation status of up to 96 gene/target assays, and as low as five % hyper-methylated DNA copies can be reliably detected in a heterogeneous sample. In short, this technology yields quantitative data comparable to bisulfite sequencing, but without the need for bisulfite conversion.

Using the Methyl-Profiler assay, the methylation status of highly relevant methylation targets in breast cancer cell lines was profiled in an effort to discover novel DNA methylation biomarkers. Several putative markers were identified and compared with results as generated by Illumina® Infinium® Methylation Assay platform, demonstrating the viability of the Methyl-Profiler method in discovering DNA methylation biomarkers. In three short procedural steps, the Methyl-Profiler PCR System can efficiently and reproducible identify novel methylation-related targets that may prove to be valuable in developing breast cancer preventative and therapeutic strategies.

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 149.
Abstract 1491: CEA interacts with TGF-β receptor and inhibits TGF-β signaling in colorectal cancers
Authors: Cao Hong , Li Ying , Yao Wenguo , Jogunoori Wilma , Thenappan Arun , Mishra Lopa
Published: February 2011

Carcinoembryonic antigen (CEA) is a tumor marker for the clinical management of colorectal cancer (CRC). The elevated blood levels of CEA are associated with metastasis and poor prognosis in CRC. There is mounting evidence that CEA enhances the metastatic potential of cancer cells. CEA increases the ability of weakly metastatic CRC to colonize the liver and to develop spontaneous hematogeneous liver and lung metastases. CEA expression has also been related with resistance to cytotoxic chemotherapy and to anoikis, a form of apoptosis caused by detachment from cell matrix. Yet the mechanism of CEA mediated metastasis is only partially understood. The TGF-β (transforming growth factor beta) signaling pathway contributes to tumorigenesis by controlling several biological processes, including cell proliferation, differentiation, migration and apoptosis. It has been reported that TGF-β regulates CEA transcription and secretion, however, little is known about the effects of CEA on TGF-β signaling. Aims: Based on the above facts, we focused on the influence of CEA on the TGF-β signaling in both normal cells and colorectal cancer cells. Results: Our preliminary data showed that CEA directly interacted with TGF-β receptors. Overexpression of CEA blocked TGF-β induced SMAD3 phosphorylation, SMAD3 translocation to nuclear and the downregulation of c-myc transcription. Targeting CEA with anti-CEA antibody rescued TGF-β response in CRC cell lines with elevated CEA expression, thereby restoring the inhibitory effects of TGF-β on the proliferation of these cancer cells. Finally, in animal experiment, we found that CEA enhanced survival of colorectal cancer cell in both local colonization and liver metastasis. Conclusion: Since CEA is a well-characterized tumor-associated antigen that is frequently overexpressed in tumors, specific antibodies targeting CEA have been developed as a novel therapeutic approach for treatment of tumors expressing CEA on their surface. Based on our study, it may be helpful to combine CEA antibody and TGF-β to inhibit cancer cell proliferation and metastasis in some cases.

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 1491.
Abstract 1493: High-resolution comparative genomic hybridization of preneoplastic and invasive esophageal squamous cell carcinoma: Identification of the earliest preneoplastic changes
Authors: Killian Jonathan Keith , Roth Mark J. , Singh Parvati D. , Walker Robert , Zhu Jack , Suuriniemi Miia , Chen Yidong , Wang Guo-Qing , Hu Nan , Taylor Philip R. , Qiao You-Lin , Dawsey Sanford M. , Meltzer Paul S.
Published: February 2011

Background: Esophageal cancer causes > 400,000 deaths/year in the world. Clinically useful early detection methods must identify these cancers and their precursor lesions at more curable stages. We conducted comparative genomic hybridization analyses of preneoplastic and invasive esophageal squamous cell carcinoma to look for gene copy number patterns that might be useful as early detection markers. The current effort focuses on aberrations associated with mild squamous dysplasia, the earliest histologic form of squamous preneoplasia.

Methods: DNA was extracted from either biopsies or surgical resections from 122 esophageal tissues spanning a spectrum including normal mucosa, squamous preneoplasia, and invasive squamous cell carcinoma. High-resolution micro-array based comparative genomic hybridization (Agilent) was used to measure regions of chromosomal gain or loss with an emphasis on identifying changes associated with the transition from normal to mild dysplasia.

Results: Chromosomal number aberrations were identified that involve several chromosomes, occur early in the neoplastic process, and progress with disease severity. Specific chromosomal number aberrations associated with mild squamous dysplasia, the earliest form of squamous preneoplasia, were uniquely identified.

Conclusions: Comparative genomic hybridization identifies patterns of chromosomal number aberrations that may distinguish patients with and without high-grade squamous dysplasia or cancer. The current effort also identifies specific changes associated with mild squamous dysplasia, the earliest form of preneoplasia, and this may help elucidate mechanisms related to the initiation of 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 1493.
Abstract 1498: The combination of immunosuppression and carrier cells significantly enhances poxvirus delivery and the efficacy of its oncolytic virotherapy in the pre-immunized host
Authors: Guo Zongsheng , Thirunavukkarasu Prag , Parimi Vamsi , O'Malley Mark E. , Austin Frances , Sathaiah Magesh , Bartlett David L.
Published: February 2011

The pre-existing anti-poxvirus immunity in cancer patients presents a hurdle to successful poxvirus-mediated oncolytic virotherapy. To overcome this hurdle, we have explored strategies of immunosuppression (IS) or/and immune evasion (IE) for successful delivery of an oncolytic vaccinia virus to tumor models in mice pre-vaccinated with a poxvirus. These include transient IS using a cocktail of three immunosuppressive drugs (IS drugs) (tacrolimus, mycophenolate mofetil and methylprednisolone sodium succinate) that have been used in organ transplant, carrier cells as a means of IE, or the combined strategy. The three drug cocktail, which targeted multiple components of innate and adaptive immunity, displayed no enhancing effects on viral infection in tumor tissue in the pre-immunized host. Using B cell knockout mice, we confirmed that B cells and the neutralizing antibodies, the later of which were not targeted by the drug cocktail, played a significant role in preventing poxvirus infection. Cancer cells as carrier cells alone were not effective to deliver the virus to tumor. Instead, the application of both IS drugs and carrier cells worked synergistically to promote the delivery to, viral infection, replication and spread inside the tumor mass and thus enhanced the efficacy of oncolytic virotherapy in an ovarian carcinomatosis model. The administraton of these IS drugs led to facilitated development of tumor-associated macrophages (TAMs) into immunosuppressive M2 phenotype (IL-10hi/IL-12low) in the tumor microenvironment. These results revealed a novel mechanism for induction of the immunosuppressive tumor microenvironment by the IS drugs, and demonstrated in principle that it is feasible to treat pre-vaccinated cancer patients with an oncolytic poxvirus when combined with both IS and IE strategies.

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 1498.
Abstract 15: Targeting cancer stem cells and vasculature by a novel anti-delta-like 4 ligand (DLL4) antibody inhibits triple-negative breast cancer tumor growth and delays tumor recurrence
Authors: Yen Wan-Ching , Fischer Marcus , Lewicki John , Gurney Austin , Hoey Timothy
Published: February 2011

Triple negative breast cancer (TNBC, ER−, PR− Her2−) accounts for about 10% of all types of breast cancer and is known to particularly aggressive and refractory to current therapies. Chemotherapeutic agents, such as taxanes, are currently the only treatment option for this type of breast cancer, however, these treatments often result in high rates of local and systemic relapse. It has been suggested that cancer stem cells drive tumor growth and progression and are preferentially resistant to many current therapies. Delta-like 4 ligand (DLL4) is an important component of the Notch signaling pathway which is known to mediate stem cell self-renewal and vascular development. We hypothesized that targeting cancer stem cells and the tumor vasculature by interfering with the DLL4/Notch pathway will improve treatment outcome. We developed anti-DLL4 antibodies that recognize either the human or murine protein and have potent binding and antagonist activities. We used these antibodies to investigate the role of DLL4 in triple negative breast cancer and to probe the mechanism in tumor and stromal cells in xenograft models derived from primary breast tumors. These studies showed that anti-DLL4 was efficacious as a single agent and in combination with paclitaxel (Taxol) against TNBC xenograft tumors. Gene expression analysis showed that anti-DLL4 affected vascular-related genes in the stroma and Notch target genes in the tumor and stroma. Inclusion of anti-DLL4 delayed breast tumor recurrence and decreased the growth rate of recurrent tumors following termination of paclitaxel treatment. Flow cytometric analysis showed that ESA+/CD44+/CD24low expressing breast cancer stem cells, BrCSC, were enriched followed by paclitaxel treatment, whereas the combination of anti-DLL4 and paclitaxel reversed paclitaxel-induced increase in this cell population. Further analysis indicated that blocking DLL4 signaling in tumor cells by anti-human DLL4 delayed tumor recurrence and decreased ESA+/CD44+/CD24low expressing BrCSC fraction and tumorigenic potential, whereas blocking DLL4 in host stroma and endothelial cells by anti-mouse DLL4 interfered with angiogenesis. The combination of both antibodies produced an additive effect. Our findings provide a rationale for targeting cancer stem cells and tumor vasculature through inhibition of the DLL4/Notch signaling for TNBC treatment.

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 15.
Abstract 1500: Modulation of recombinant vaccinia virus vector immunogenicity
Authors: Raafat Nermin , Mengus Chantal , Heberer Michael , Spagnoli Giulio C. , Zajac Paul
Published: February 2011

Recombinant poxviruses expressing tumor associated antigens (TAAs) are evaluated since 20 years as immunogenic vaccine vector in clinical trials. Possible limitation to recombinant viral vector is due to either prior systemic immunity to poxviruses or immunodominance of viral antigens which may reduce the induction of immune response against weaker tumor antigens. To address this issue, we developed a recombinant Vaccinia virus expressing HSV type I protein ICP47. This protein down-regulates MHC class-I antigen presentation by blocking the transporter associated with antigen processing (TAP), which translocates peptides, generated by proteasomal protein degradation, into the endoplasmic reticulum for loading onto MHC class I molecule.

Herpes simplex virus (HSV) US12 gene, coding for infected cell protein 47 (ICP47) was introduced into wild type vaccinia virus and into a r.VV expressing MART-1/Melan-A27–35 HLA-A201 endoplasmic reticulum (ER)-targeted epitope. Following infection with non-replicating recombinant virus, effect of ICP47 expression on cell surface MHC-class-I, MHC class-II and co-stimulatory molecules was characterized by antibody staining and FACS analysis. Human T-lymphocytes were stimulated in vitro with autologous CD14+ cells infected with r.VV-US12, r.VV-Mart-US12 or control virus. Responsiveness of specific CD8+ and CD4+ to viral proteins and recombinant epitopes were monitored by MHC-multimer staining and interferon gamma (IFNg) expression analysis.

Cells infected with HSV-US12-r.VV, demonstrated a decreased ability of presenting MHC class-I antigens to CD8+ T cells whereas MHC-class-II restricted presentation to CD4+ T cells remained unaffected. Co-expression of ER-Melan-A/Mart-126–35 appeared to partially compensate for the ICP47 related surface MHC class-I molecule down-regulation and preserve a strong capacity to induce CTL response against the TAA derived peptide.

Thus, viral vectors expressing ICP47 confirmed a diminished TAP-dependant processing of endogenous class-I restricted epitopes while the immunogenic potential of recombinant epitopes directly targeted to the ER was enhanced. Such reagents could become of high relevance especially in multiple-boost vaccine protocol required in cancer immunotherapy.

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 1500.
Abstract 1511: mda-7/IL-24 potently induces apoptosis in human leukemia cells through a process involving induction of ER stress
Authors: Rahmani Mohamed , Mayo Mandy , Dash Rupesh , Dent Paul , Fisher Paul B. , Grant Steven
Published: February 2011

mda-7/IL-24, a member of the IL-10 cytokine gene family, has been shown to induce cell death in various epithelial cancer cell types while exhibiting relatively little toxicity toward normal cells. Currently, the effects of mda7/IL-24 on myeloid leukemia cells (AML) have not been extensively characterized. In the present study, we report that treatment with recombinant GST-mda7/IL24 strikingly induces apoptosis in diverse myeloid leukemia cell lines including U937, MV4-11, EOL-1 (both FLT3 mutant), and MLL/ENL cells, which display certain leukemia stem cell-like properties. In addition, mda7/IL24 potently induces apoptosis in and suppresses the colony formation capacity (L-CFU) of primary blasts isolated from multiple patients with AML. In contrast, mda-7/IL-24 exerted only minimal effects on normal CD34+ progenitor cells. These effects were associated with profound mitochondrial injury manifested by cytochrome c and AIF release into the cytosol, caspase-3 activation, and PARP cleavage. The apoptotic effects of mda7/IL24 were associated with a potent induction of ER stress in leukemia cell lines as well as in primary AML blasts, manifested by accumulation of GADD153/CHOP, GADD34, GRP78, and IRE1α. Notably molecular studies with shRNA directed against IRE1α revealed that knockdown of IRE1α significantly enhanced mda7/IL24-mediated apoptosis in U937 cells, suggesting that induction of IRE1α plays a protective role against mda7/IL24 lethality. In addition treatment with mda7/IL24 resulted in down-regulation of the anti-apoptotic protein Mcl-1, and marked accumulation of the pro-apoptotic proteins Bim and Noxa. Notably, ectopic expression of Mcl-1 or knock-down of Bim or Noxa with shRNA markedly decreased mda7/IL24-mediated cell death in leukemia cells. Collectively, these findings indicate that mda7/IL24 strikingly induces apoptosis in human myeloid leukemia through a process that involves ER stress induction, Mcl-1 downregulation, and Bim and Noxa upregulation. They also suggest that mda7/IL24 warrants attention as a potential addition to the therapeutic armamentarium in leukemia and possibly other hematologic 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 1511.
Abstract 1512: The linamarase/linamarin/glucose oxidase cocktail cures human gliomas in rats
Authors: Izquierdo Marta L. , Gil Jon , Girald Willie
Published: February 2011

Glioblastoma multiforme (GBM) is one of the dedliest forms of cancer, with an average survival time of approximately one year despite aggressive surgery, radiotherapy and chemotherapy. We will report a therapeutic procedure with potential clinical utility, by which the two main energy pathways of the tumor cells, oxidative phosphorylation and aerobic glycolysis, are simultaneously disrupted. First, the neoplastic cells must receive the plant linamarase gene (LI), which mediates the transformation of linamarin (LIN) into cyanide, glucose and acetone. Shortly after, we administer a systemic treatment with both linamarin and glucose oxidase (GOD) for 7 days. This creates a synergistic effect by which the neoplasm collapses in a few days. Autophagy is the cellular death mechanism involved in the eradication of the tumor. One hundred percent of the tumors disappear and neither relapse nor side effects are manifested. This therapeutic procedure also destroys the highly metastatic stem cell population from the human glioblastoma implants, thus preventing recurrence of the disease. This simple treatment is the first that can cure in a few days human brain tumors xenotransplanted into the brain of nude rats.

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 1512.
Abstract 1519: Tyrosine kinase inhibitors are potent reversal agents for MRP7 (ABCC10)-mediated multidrug resistance
Authors: Sodani Kamlesh , Kuang Ye-Hong , Shen Tong , Vispute Saurabh , Tiwari Amit K. , Lei Yu , Lee Jeferson , Chen Xiang , Ashby Charles R. , Chen Zhe-Sheng
Published: February 2011

ATP binding cassette (ABC) transporters play a crucial role in the development of multidrug resistance (MDR) leading to failure of the cancer chemotherapy. Previously, we and others have reported that lapatinib, erlotinib (EGFR tyrosine kinase inhibitors/TKIs) and nilotinb, imatinib (BCR-Abl TKIs) reverse ABCB1- and ABCG2-mediated MDR. MRP7/ABCC10, a member of MRP family, shares a structural homology with other ABC transporters such as P-gp/ABCB1. MRP7 is involved in effluxing several anticancer drugs resulting in poor chemotherapeutic outcome. In an effort to reverse MRP7-mediated MDR, we discovered that EGFR TKIs lapatinib, erlotinib, and BCR-Abl TKIs imatinib, nilotinib enhances the sensitivity of MRP7-transfected HEK293 (HEK-MRP7-2) cells to the established MRP7 substrates, such as paclitaxel, docetaxel, vincristine and vinorelbine in concentration-dependent manner. However, there was no significant effect of these TKIs on the sensitivity of control HEK293-pcDNA3.1 cells. In addition, these TKIs increased the intracellular accumulation of [3H]paclitaxel, inhibiting MRP7-mediated [3H]paclitaxel efflux from HEK-MRP7-2 cells. Moreover, Western blot analysis showed no significant change in the MRP7 expression level in the MRP7 overexpressing cell line on treatment with aforementioned TKIs. We conclude that both EGFR TKIs (lapatinib, erlotinib) and BCR-Abl TKIs (imatinib, nilotinib) reverse MRP7-mediated MDR through inhibition of the drug efflux function of MRP7, suggesting that TKI based combinational chemotherapy may be useful in cancer clinical practice.

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 1519.
Abstract 152: Methylated-DNA enrichment and PCR array technology: A qPCR-based method to rapidly screen for changes in promoter DNA methylation patterns
Authors: Shaffer Jonathan M. , Gu Xiujing , Boon Kathy
Published: February 2011

As the only known enzymatic modification of DNA in mammals, methylation of cytosines at CpG dinucleotides is recognized as a “third pathway” in Knudson's two-hit hypothesis for cancer which suggests that at least two DNA insults (hits) are required for cancer progression. This epigenetic event alters gene expression patterns associated with normal development and disease progression without changing the actual DNA sequence. In cancer, hypermethylation of tumor suppressor gene promoters abolishes their transcription, while hypomethylation of proto-oncogene promoters increases their transcription, effectively driving tumorigenesis in either case. Given the importance of this event for tumorgenesis, various techniques have been developed to identify DNA methylation based diagnostic biomarkers. Unfortunately, these methods often fall short in terms of throughput capacity, cost, or equipment requirements.

This work presents a novel combination of technologies to efficiently screen for changes in DNA methylation patterns within a panel of genes simultaneously. Using lung cancer as an experimental model, this study establishes that methylated DNA enrichment combined with real-time PCR (qPCR) technology offers great potential to identify putative biomarkers. This one-day assay is quite simple, and with very little hands-on time it can be easily adapted for high-throughput screening. A genomic DNA sample of interest is sheared, denatured, and incubated with a highly specific anti-5-methylcytosine antibody immobilized to a resin. The methylated DNA is then released, purified over a column, and applied to a pathway-focused qPCR array. The sensitivity of the method is very high; even one methylated CpG dinucleotide is enough to selectively enrich for a methylated target of interest, and the assay detection limit is well below 2.5% of a target in a mixed genomic DNA background. Importantly, data derived from this method has been validated with data derived from the Illumina® Infinium® Methylation Assay platform, further attesting to the potential for discovering methylation biomarkers with this system.

In conclusion, the combination of methylated-DNA enrichment and qPCR array technology has been extensively optimized to discriminate methylated-CpG dinucleotides with low background. With this method, researchers will be able to quickly determine whether changes in gene expression (upregulation or downregulation) are associated with promoter methylation changes. This combination of methylated-DNA enrichment with qPCR array technology offers great potential as a methylated CpG dinucleotide screening tool, without the high cost.

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 152.
Abstract 1525: RLIP76 transports sunitinib and sorafenib and mediates drug resistance in kidney cancer
Authors: Singhal Sharad S. , Sehrawat Archana , Sahu Mukesh , Singhal Preeti , Vatsyayan Rit , Lelsani Poorna C R , Yadav Sushma , Awasthi Sanjay
Published: February 2011

RLIP76 is a stress-responsive membrane protein implicated in the regulation of multiple cellular signaling pathways. It functions as the predominant glutathione-electrophile conjugate (GS-E) transporter in cells. We have shown that RLIP76 plays a crucial role in defending cancer cells from radiation and chemotherapeutic toxin-mediated apoptosis, and its inhibition by antibodies or depletion by siRNA or antisense causes apoptosis in a number of cancer cell types. Recently, we have demonstrated for the first time the striking anti-neoplastic effects with no evident toxicity in terms of either weight loss or metabolic effects for the antibody, antisense and siRNA in a renal cell xenografts model of Caki-2 cells (Singhal et al., Cancer Res., 2009, 69: 4244). Present studies were performed to determine if RLIP76 targeting is more broadly applicable in other kidney cancer cell lines, to compare the signaling effects of RLIP76 antisense with kinase inhibitors used in treatment of renal cell carcinoma, and to determine whether kinase inhibitors were substrates for transport by RLIP76. Results of these studies show that sorafenib as well as sunitinib are substrates for transport by RLIP76 thus are competitive inhibitors of GS-E transport. Furthermore, kinase inhibition in the ERK as well as PI3K pathways by RLIP76 depletion is more profound and consistent and is more widely apparent in a number of renal carcinoma cell lines. These studies support the validity of RLIP76 as a target in kidney cancer therapy, and the functional model in which RLIP76 provides protection from chemical and radiant stress through its transport activity. Results of these studies revealed for the first time that sorafenib as well as sunitinib, receptor tyrosine kinase inhibitors (RTKIs), are substrates for transport by RLIP76. These studies offer strong support for our overall hypothesis that RLIP76 is an overarching anti-apoptosis mechanism that, if inhibited, can be more broadly effective in the treatment of renal cell carcinoma. (Supported in part by NIH Grants CA 77495 and CA 104661 (to SA), Cancer Research Foundation of North Texas (to SSS & SY), Institute for Cancer Research and the Joe & Jessie Crump Fund for Medical Education (to SSS))

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 1525.
Abstract 1526: Epithelial mesenchymal transition (EMT) is associated with non-transporter resistance to taxanes in human ovarian cancer cell
Authors: Wang Cindy Y. , Duran George E. , Francisco E. Brian , Juric Dejan , Witten Daniela , Tibshrani Rob , Sikic Branimir I.
Published: February 2011

Taxanes are important drugs in the treatment of ovarian cancers, but their efficacy is limited by intrinsic and acquired drug resistance. Over-expression of the MDR1 gene and its product, P-glycoprotein, is a well-characterized resistance mechanism to taxanes, but non-MDR1 taxane resistance mechanisms are not well elucidated. To study the mechanisms of non-MDR1 multidrug resistance related to taxanes, we established multiple MDR1-negative and MDR1-positive taxane resistant variants from four ovarian cancer cell lines (A2780/1A9, ES-2, MES-OV and OVCAR-3) by continuous exposure of the cells to either paclitaxel or docetaxel with or without the P-glycoprotein inhibitor PSC-833 (Valspodar). We profiled gene expression and gene copy number alterations in these cell lines using cDNA microarrays, and identified a transcriptomic signature that predicts in vitro non-MDR1 resistance, a portion of which was imprinted by gene dosage changes. Functional network analyses for genes associated with the taxane resistance signature revealed two highly significant networks built around FN1 and CDKN1A which are associated with cell adhesion, cell-to-cell signaling and cell cycle regulation. We also identified epithelial-mesenchymal transition (EMT) marker genes which are significantly associated with non-MDR1 resistance. Migration potential in wound-scratch-assay was markedly enhanced in non-MDR1 resistant variants compared to parental cells. Our results suggest that ECM-interacting genes, EMT-like changes and cell cycle regulatory elements may play important roles in resistance to taxanes.

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 1526.
Abstract 153: DNA methylation alters DNA and chromatin structure leading to genetic instability in mammals
Authors: Wang Guliang , Vásquez Karen M.
Published: February 2011

Chromosomal breakpoints and translocation hotspots in human cancers are often found near sites of aberrant DNA methylation. DNA hypomethylation can lead to illegitimate recombination events and can stimulate V(D)J recombination in the immunoglobulin genes. However, this co-localization of chromosomal breakage cannot be explained by previously proposed mechanisms of CpG hypermethylation-induced genetic instability, e.g., deamination-induced point mutation, or epigenetic gene silencing, because these events should not lead directly to DNA double-strand breaks. In this study, we determined the effect of cytosine methylation on the stability of CpG-rich sequences in mammalian cells and on chromosomes in mice, without altering the global genome-wide DNA methylation status. We found that methylation of specific CpG repeats induced higher frequencies of deletions and rearrangements within and surrounding the methylated repeats than that found with unmethylated CpG repeats. In addition, we found that those mutations induced by the methylated CpG repeats had a broader size distribution than that found with unmethylated CpG repeats. In an effort to elucidate the mechanism of hypermethylation-induced genetic instability, we discovered that unusual structural features of the methylated CpG sequences precluded local nucleosome assembly, leading to an increase in mutations. Thus, we propose a novel process of DNA methylation-induced genetic instability in mammals in which methylation of CpG-rich sequences can alter both DNA and chromatin structures, leading to DNA double-strand breaks.

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 153.
Abstract 1534: Bioassay-guided identification of novel P-glycoprotein inhibitors from traditional Chinese medicines
Authors: Ravula Ranadheer , Wang Jeffrey , Huang Ying
Published: February 2011

Multi-drug resistance (MDR) is an obstacle for therapeutic success of anticancer agents. Overexpression of P-glycoprotein (P-gp), encoded by ABCB1 gene, plays a key role in conferring MDR via active efflux of anticancer drugs from cells. Previous efforts with several generations of P-gp inhibitors had not been successful in modulating clinical MDR. Recently, an increasing number of cancer patients are using complementary and alternative medicines, in particular, traditional Chinese medicines (TCMs), in combination with conventional anticancer agents. The purpose of this study is to examine the effects of TCM extracts on modulating P-gp function. We initiated our study from four single herbal products (Glycyrrhiza uralensis, Hibiscus syriacus, Tripterygium wilfordii, and Cephalotaxus sinensis) and one formula of herbal mixture (Si-Wu-Tang), using a bio-assay guided fractionation method. Crude extracts were firstly prepared with ethanol. The most active extracts identified were further extracted with hexane, chloroform, acetone and ethanol sequentially to obtain fractions of increasing polarity. The MDR modulating effects of the crude extracts and individual fractions were evaluated based on their capability to enhance daunorubicin (DNR) accumulation in P-gp over-expressing human leukemia cell line K562/DOX. The intracellular fluorescence intensity in the presence or absence of test drugs or known P-gp inhibitor cyclosporine A (10 µM) was measured by flow cytometer. The crude extracts were also tested for cytotoxicity against K562/DOX cells by the MTS cell proliferation assay. This study revealed that among the five TCMs, the crude extracts of Tripterygium wilfordii demonstrated a dose-dependent effect on increasing the DNR accumulation, indicating the presence of novel P-gp inhibitor(s). Upon further separation, the chloroform fractions of this herb showed the highest P-gp inhibitory activity. However, known compounds present in this herb, celastrol, triptolide and myristic acid did not show effects on DNR accumulation. Most of the plant extracts tested were able to inhibit the growth of K562/DOX cells with Cephalotaxus sinensis being the most effective, consistent with literature reports that this herb contains highly cytotoxic compound homoharringtonine and congeners. The potency of P-gp inhibition for the five TCMs was not correlated with their cytotoxicity. In conclusion, our results demonstrated that the chloroform fractions of Tripterygium wilfordii contain unknown components for P-gp inhibition. Our current efforts are focused on isolation and identification of active compounds from it.

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 1534.
Abstract 1537: Dual-specificity phosphatase-2 negatively controls chemoresistance in cancer cells
Authors: Shih-Chieh Lin , Shaw-Jenq Tsai
Published: February 2011

The limitation of clinical cancer therapy is due to a lot of mechanisms including influence of uptake, metabolism and export of drug from a single cell that contribute to drug resistance at the cellular level. In addition, tumor microenvironment also plays an important role in promoting drug resistance. For example, hypoxia has been reported to induce drug resistance by modulating expression of numerous genes. It has been shown that targeting individual hypoxia-regulated gene decreases drug resistance. However, it is an inefficient and infeasible way to target individual drug resistance-related genes one by one. Here we show that extracellular signal-regulated kinase 1/2 (ERK1/2), a survival pathway, is activated by hypoxia and blocking ERK1/2 pathway attenuates hypoxia-induced drug resistance. Furthermore, we also find that dual-specificity phosphatase-2 (DUSP2), a nuclear phosphatase that controls activity of ERK1/2, is inhibited by hypoxia through transcriptional repression. Inhibition of DUSP2 results in prolonged activation of ERK and increasing cell survival. Overexpression of DUSP2 causes cell apoptosis under normoxia and decreases hypoxia-induced drug resistance while stable knockdown DUSP2 increases drug resistance under normoxia. Moreover, re-expression of DUSP2 under hypoxia blocks tumor growth and enhances drug sensitivity in xenografted mice. Taken together, we identified an important role of DUSP2 involving hypoxia-mediated drug resistance and targeting DUSP2 might provide more specific and efficient way for 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 1537.